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MURAKAWA HidekiGraduate School of Engineering / Department of Mechanical EngineeringAssociate Professor
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■ Award- Sep. 2024 日本混相流学会, 2023年度 日本混相流学会 論文賞, 超音波トモグラフィ法を用いたガリウム合金中を上昇する気泡鎖の断面分布に及ぼす水平磁場の影響解明
- Aug. 2015 日本混相流学会, 2014年度日本混相流学会賞 奨励賞, 超音波パルスドップラ法の高度化と混相流計測への応用Japan society
- Oct. 2007 日本機械学会 動力エネルギーシステム部門, 日本機械学会 動力エネルギーシステム部門優秀講演表彰, 第12回動力・エネルギー技術シンポジウム
- Oct. 2005 日本機械学会, 日本機械学会第83期流体工学部門講演会優秀講演表彰, 第83期流体工学部門講演会
- Corresponding, Nov. 2023, Proc. of 12th International Symposium on Measurement Techniques for Multiphase Flow (ISMTMF 2023), #A16, EnglishDevelopment of an evaluation method for bubbles behavior in a liquid metal using ultrasonic computed tomography,[Refereed]International conference proceedings
- Oct. 2023, Proc. of 14th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering (ISUD2023), 75 - 78, EnglishMeasurements of bubble rising velocity using ultrasonic tomography[Refereed]International conference proceedings
- Corresponding, Oct. 2023, Proc. 14th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering (ISUD2023), 71 - 74, EnglishEffect of transverse magnetic field on rising bubble behavior in gallium eutectic alloy[Refereed]International conference proceedings
- Elsevier BV, Oct. 2023, International Journal of Multiphase Flow, 170, 104649, English[Refereed]Scientific journal
- Jul. 2023, Proc. of ASME ‐ JSME ‐ KSME Fluids Engineering Division (AJKFED 2023), #4-04-2-01, EnglishDevelopment of Measurement Method of Bubble Behavior using High-speed Ultrasonic TomographyInternational conference proceedings
- Corresponding, Apr. 2023, Proc. of the 11th International Conference on Multiphase Flow (ICMF 2023), #608, EnglishBoiling heat transfer characteristics of magnetic nanofluids under magnetic fieldInternational conference proceedings
- Apr. 2023, Proc. of the 11th International Conference on Multiphase Flow (ICMF 2023), #751, EnglishFlow behaviors and void fraction distribution in mini-channel cross-flow vaporizerInternational conference proceedings
- Corresponding, Apr. 2023, Proc. of the 11th International Conference on Multiphase Flow (ICMF2023), #362, EnglishVisualization of continuously rising bubbles in gallium alloyInternational conference proceedings
- Elsevier BV, Feb. 2023, Applied Thermal Engineering, 220, 119697 - 119697Scientific journal
- Lead, Japan Society of Mechanical Engineers, Aug. 2022, Mechanical Engineering Journal, 9(4) (4), 22 - 00069, English[Refereed]Scientific journal
- Elsevier BV, Mar. 2022, Applied Thermal Engineering, 204, 117963 - 117963[Refereed]Scientific journal
- Oct. 2021, Proc. of International Conference on Power Engineering-2021, ICOPE-2021-0156Study on the effect of tube gap on nucleate boiling heat transfer coefficient in horizontal tube bundle[Refereed]International conference proceedings
- Corresponding, Oct. 2021, Proc. of International Conference on Power Engineering-2021, ICOPE-2021-0219Effects of water accumulation in the proton exchange membrane and the gas diffusion layer on the power generation performance of PEFC[Refereed]International conference proceedings
- Corresponding, Oct. 2021, Proc. of International Conference on Power Engineering-2021, ICOPE-2021-0285Effect of bubble motion on local heat transfer around a tube across horizontal in-line and staggered tube bundles in bubbly and intermittent flows[Refereed]International conference proceedings
- Sep. 2021, Measurement, 182, 109654[Refereed]Scientific journal
- Elsevier BV, Aug. 2021, Flow Measurement and Instrumentation, 80, 101997 - 101997[Refereed]Scientific journal
- Elsevier BV, Jul. 2021, Applied Thermal Engineering, 194, 117096 - 117096[Refereed]Scientific journal
- Jun. 2021, Proc. of 13th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, 72 - 75Measurements of continuously released bubbles motion in liquid metal using ultrasonic techniques[Refereed]International conference proceedings
- Boiling two-phase flows in cross-flow type mini-channel evaporator were visualized by neutron radiography. Refrigerant vertically upward flow of HFC134a [CH2FCF3] in 21 parallel channels with the hydraulic diameter of 1.47 mm was heated by the heating medium of fluorocarbon FC3283. Void fraction distributions of evaporating two-phase flows were measured by neutron radiography. The effect of the inlet orifices for each refrigerant channel to prevent flow instability was evaluated. The refrigerant was supplied to the test section as subcooled liquid with the mass flux of 50 to 100 kg/(m2s). The heating medium was supplied with the mass flux of 460 and 920 kg/(m2s) and at the inlet temperature of 47.1 to 67.2 °C. As the result, it is shown that void fraction close to the inlet of heating medium was relatively higher. Flow instability of boiling flows and the effect of the inlet orifices were not observed.Materials Research Forum LLC, Feb. 2020, Materials Research Proceedings, 15, 274 - 280[Refereed]Scientific journal
- Materials Research Forum LLC, Feb. 2020, Materials Research Proceedings, 15, 268 - 273[Refereed]Scientific journal
- 2020, Experimental Thermal and Fluid Science, 112, 109957, English[Refereed]Scientific journal
- Japan Society of Mechanical Engineers, 2020, Mechanical Engineering Journal, 7(4) (4), 20 - 00131[Refereed]Scientific journal
- Nov. 2019, Proc. of The 30th International Symposium on Transport Phenomena (ISTP30), #ISTP024Effect of Partially Inserted Boiling Heat Transfer Enhanced Tube on Nucleate Boiling Heat Transfer in Horizontal Tube Bank[Refereed]International conference proceedings
- Oct. 2019, Proc. of International Conference on Power Engineering-2019, 767 - 772Boiling heat transfer characteristics in horizontal in-line tube bundle with partially inserted heat transfer enhanced tube by thermal spray coating[Refereed]International conference proceedings
- Effects of water distribution on the electrical characteristics of polymer electrolyte fuel cell© ICOPE 2019 - 7th International Conference on Power Engineering, Proceedings. All rights reserved. Water management in a polymer electrolyte fuel cell (PEFC) is a key topic for PEFC operation. It is well known that the water accumulation in the gas diffusion layer (GDL) increases the polarization resistance, whereas the increases of the water content, λ, in the proton exchange membrane (PEM) decreases the proton conductivity. In this study, neutron radiography and the electrochemical impedance spectroscopy (EIS) were employed simultaneously for evaluating the relation between the water contents and the polarization losses in a PEFC. Water accumulation started in the GDL, and a large amount of water existed in the GDL under the lands. The water-accumulation area extended to the GDL under the channels during the PEFC operation. Water accumulation in the channel disturbed the air supply resulting in the rapid increase of the polarization resistance. Ion conductivity of the membrane increased in proportion to the water content. However, the effect of the water contents on the ion conductivity was less at low λ than a correlation proposed by Springer et al. for λ > 1.Oct. 2019, Proc. of International Conference on Power Engineering-2019, 1081 - 1084[Refereed]International conference proceedings
- Aug. 2019, Proc. of The 25th IIR International Congress of Refrigeration, #1095Void fraction characteristics of adiabatic one-component vertically upward two-phase flows in circular and non-circular small diameter tubes[Refereed]International conference proceedings
- Jan. 2019, KURNS-EKR (Web), (3) (3), 55‐59 (WEB ONLY), Japanese中性子イメージングの高度化
- Sep. 2018, 11th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, EnglishDevelopment of a hybrid ultrasonic flow meter with the use of pulsed Doppler and time-of-flight[Refereed]International conference proceedings
- This study investigated the local characteristics of void-fraction distribution and heat transfer around tubes in two-phase flows under adiabatic conditions using vertical duct test sections with inner dimensions of 90 × 90 mm . Two kinds of test sections, in-line and staggered tube bundles, each containing five columns and eight rows, were employed for the measurements. The tube diameter of each was 15 mm, and the pitch-to-diameter ratio was 1.5 for both bundles. The working fluids were air and water, and the experiments were performed under atmospheric pressure in a temperature range of 20–25 °C. Superficial liquid velocity, J , and gas velocity, J , ranged from 0.1 to 0.3 m/s and 0.03 to 1.19 m/s, respectively. Two-dimensional void-fraction distributions were obtained using X-ray radiography and the local heat-transfer coefficients were measured using a platinum wire electrode placed on a tube that could be rotated. In the experiments, the time-averaged void fraction increased at the maximum and vertical minimum gaps for the in-line tube bundle, whereas the void fraction increased upstream of the tubes for the staggered tube bundle. In the bubbly flow condition, enhancement of the heat transfer by bubbles motion clearly occurred between ±90 and 180° for the in-line tube bundle, and increased all over the pipe for the staggered tube bundle. The increase in the local heat transfer coefficients by bubbles motion was more apparent for the in-line tube bundle. The average heat transfer coefficient in the staggered tube bundle was higher than that in the in-line tube bundle in the bubbly flow regime, whereas the results were opposite in the intermittent flow regime. 2 L GLead, Elsevier BV, Aug. 2018, Nuclear Engineering and Design, 334, 66 - 74[Refereed]Scientific journal
- In transit-time ultrasonic flow meters (TOF), the flow rate is derived from the transit time of an ultrasonic pulse between two ultrasonic transducers. To convert the transit time into flow rate, a profile factor (PF) is required. Because the PF strongly depends on the velocity profile, a precise calibration of the PF is essential to the accuracy of the TOF. Hence, a field calibration, referred to as on-site calibration, is desirable. In this study, a hybrid ultrasonic flow meter that helps calibrate the TOF using ultrasonic Doppler velocimetry (UDV) is proposed for on-site calibration by integrating the velocity profiles over the cross-sectional area of a pipe. Thus, a new system of hybrid ultrasonic flow meter was developed. The maximum flow rate measured using a conventional UDV is significantly lower than that measured using the TOF. Therefore, a system was developed to measure higher velocities and flow rates. The system is novel in that the transit time and velocity profile can be simultaneously measured using a de-aliasing method. To evaluate the influence of the velocity profile on the PF, experiments were conducted under a wide range of flow-rate conditions, which otherwise cannot be implemented using the conventional UDV. To evaluate the influence of the velocity profile in the pipe, an obstacle plate was placed at 8D upstream the test section. Radially arranged measuring lines were employed. The experimental results show that increasing the number of measuring lines did not improve the accuracy of the TOF. On the other hand, the flow rate could be accurately obtained using the proposed UDV by measuring the velocity profile even under distorted flow conditions. Furthermore, the calibration of the PF based on the flow rate obtained using the proposed UDV was found to be feasible.Elsevier Inc., Jun. 2018, Experimental Thermal and Fluid Science, 94, 49 - 58, English[Refereed]Scientific journal
- Apr. 2018, 9th European-Japanese Two-Phase Flow Group Meeting, EnglishTwo-phase flow and heat transfer characteristics in horizontal tube bundles[Refereed]International conference proceedings
- Mar. 2018, 10th International Conference on Boiling and Condensation Heat Transfer, EnglishPool boiling heat transfer around a horizontal low thermal conductivity tube under isothermal wall condition[Refereed]International conference proceedings
- Japan Society of Mechanical Engineers, 2018, The Proceedings of the National Symposium on Power and Energy Systems, 2018.23(0) (0), D212 - D212Scientific journal
- Dec. 2017, 10th International Symposium on Measurement Techniques for Multiphase Flow, EnglishDevelopment of an ultrasonic technique for measuring liquid-metal two-phase flow[Refereed]International conference proceedings
- Oct. 2017, The Ninth JSME-KSME Thermal and Fluids Engineering Conference, EnglishPool Boiling Heat Transfer around a Horizontal Low Thermal Conductivity Tube with Thermal Spray Coating with Isothermal Heating[Refereed]International conference proceedings
- Oct. 2017, The Ninth JSME-KSME Thermal and Fluids Engineering Conference, EnglishDevelopment of an ultrasonic technique for measuring phase velocities in liquid-metal two-phase flow[Refereed]International conference proceedings
- Jun. 2017, The 2nd Int. Conf. of Interfacial Phenomena and Heat Transfer, EnglishVoid Fraction Characteristics of Gas-Liquid Two-Phase Flows in Small Diameter Square Tube[Refereed]International conference proceedings
- Japan Society of Mechanical Engineers, 2017, The Proceedings of the National Symposium on Power and Energy Systems, 2017.22(0) (0), F114 - F114Scientific journal
- TWO-PHASE FLOW BEHAVIOR AND HEAT TRANSFER CHARACTERISTICS IN KETTLE REBOILEREffects of the tube array, such as in-line and staggered, on void-fraction distribution and heat transfer coefficient around a tube were experimentally investigated. The test section was vertical duct with inner size of 90 x 90 mm(2). Diameter of the tubes was 15 mm, and the pitch-to-diameter ratio was 1.5 for both tube bundles. Working fluids were air and water. Experiments were carried out at superficial gas velocity defined at minimum area section, J(G), of 0.10 to 0.89 m/s, superficial liquid velocity, J(L), of 0.1 to 0.3 m/s, under the atmospheric condition. Measurements of void-fraction distribution were carried out using X-ray radiography. In addition, heat transfer coefficient around a tube was measured and the heat transfer coefficients in association with the flow regime and the void fraction distribution were evaluated. Time-average void-fraction was higher around upstream of a tube than that of downstream at bubbly flow condition for both bundles. Under intermittent flow condition, time-average void fraction at the maximum gap were higher than that around the other points in both tube bundles. For in-line tube bundle, enhancement of the heat transfer clearly appeared between +/- 90 to 180 degrees. For staggered tube bundle, the heat transfer increased all over the pipe.AMER SOC MECHANICAL ENGINEERS, 2017, PROCEEDINGS OF THE ASME POWER CONFERENCE JOINT WITH ICOPE-17, 2017, VOL 1, English[Refereed]International conference proceedings
- Nov. 2016, Proc. of 4th International Forum on Heat Transfer, EnglishVoid fraction characteristics of gas-liquid two-phase floes in small diameter square tube[Refereed]International conference proceedings
- Sep. 2016, Proc. of 10th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, EnglishInfluence of velocity distribution on accuracy of transit-time ultrasonic flow meter[Refereed]International conference proceedings
- Sep. 2016, Proc. of 10th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, EnglishEvaluation of measurement accuracy of a dealiasing method for use with ultrasonic pulsed Doppler[Refereed]International conference proceedings
- Sep. 2016, Proc. of 10th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, EnglishDevelopment of a Budget Multiwave UVP System for Two-phase Flow Measurement and Some Applications[Refereed]International conference proceedings
- In the article, the application of the electrical spike, instead of the tone-burst, to the ultrasonic pulsed-Doppler velocity profiling the first time is presented. To generate ultrasound, the ultrasonic sensor is excited by the spike. For the Doppler method, the spike excitation was not used previously. It has been used with wideband signal processing methods. In our study, first, the fluid-velocity profile measurement using spike excitation has been carried out for single-phase pipe flow. The received data have been validated by the logarithmic law of the wall, for turbulent flow regime. The flow rate calculated by using the mean velocity profile well coincides with the flow-meter data. Furthermore, the spike signal and the Doppler method are used in the multiwave ultrasonic velocity profile (UVP) method, for the bubbly flow measurement. The experiments show that, if the spike signal is slowly damped, the generated ultrasonic wave is similar to the tone-burst that is required for the Doppler method, but in this case, usually the pulse length is smaller and depends on the damping and sensor characteristics. The autocorrelation technique is used for echo signal processing. The derived UVP systems inherit the advantages from both the spike excitation and Doppler method.SPRINGER, Aug. 2016, EXPERIMENTAL TECHNIQUES, 40(4) (4), 1235 - 1248, English[Refereed]Scientific journal
- The condensation rate of vapor bubbles, defined by v(c) = -dR/dt where R is the spherical-equivalent bubble radius, t is time, is an important parameter to determine the interfacial-condensation heat and mass transfer in subcooled boiling. Previous measurements of the condensation rate were mainly based on the optical visualization. In the paper, the development of a new method that uses two ultrasonic frequencies for the measurement of the condensation rate in subcooled boiling is presented. The ultrasonic velocity profile (UVP) method is used for the velocity measurement. Two simultaneous UVP measurements by the two frequencies are exploited. The principle of the new condensation-rate-measurement method is established. In the method, the UVP data of the bubble surface velocity are used. In subcooled boiling, the bubble-surface velocity is affected by the condensation. The UVP measurement must capture correctly the condensation effect on the bubble-surface velocity. In order to confirm the applicability of the UVP method to the measurement of the surface velocity in this case, the growth rate of air bubbles from a nozzle submerged in water is measured and compared with the result of optical visualization and digital image processing. Such growth process is analogous to that of vapor bubbles in a boiling process, and it is the inverse of the condensation process. Evaluation of the new condensation-rate-measurement method is carried out by the measurements of adiabatic air-water-bubbly column and subcooled pool boiling in vertical round tube. (C) 2016 Elsevier Ltd. All rights reserved.PERGAMON-ELSEVIER SCIENCE LTD, Aug. 2016, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 99, 159 - 169, English[Refereed]Scientific journal
- May 2016, Proc. of 9th International Conference on Multiphase Flow, #433, EnglishEvaluation of void fraction around a tube in two-phase flow across horizontal tube bundle[Refereed]International conference proceedings
- The ultrasonic pulsed Doppler method (UDM) can obtain a velocity profile along the path of an ultrasonic beam. However, the UDM measurement volume is relatively large and it is known that the measurement volume affects the measurement accuracy. In this study, the effect of the measurement volume on velocity and flow rate measurements is analytically and experimentally evaluated. The velocities measured using UDM are considered to be ensemble-averaged values over the measurement volume in order to analyze the velocity error due to the measurement volume, while the flow rates are calculated from the integration of the velocity profile across the pipe. The analytical results show that the channel width, i.e. the spatial resolution along the ultrasonic beam axis, rather than the ultrasonic beam diameter, strongly influences the flow rate measurement. To improve the accuracy of the flow rate, a novel method using a multi-wave ultrasonic transducer consisting of two piezo-electric elements with different basic frequencies is proposed to minimize the size of the measurement volume in the near-wall region of a pipe flow. The velocity profiles in the near-wall region are measured using an 8 MHz sensor with a small diameter, while those far from the transducer are measured using a hollow 2 MHz sensor in the multi-wave transducer. The applicability of the multi-wave transducer was experimentally investigated using the water flow-rate calibration facility at the National Institute of Advanced Industrial Science and Technology (AIST). As a result, the errors in the flow rate were found to be below -1%, while the multi-wave method is shown to be particularly effective for measuring higher flow rates in a large-diameter pipe.IOP PUBLISHING LTD, Feb. 2016, MEASUREMENT SCIENCE AND TECHNOLOGY, 27(2) (2), English[Refereed]Scientific journal
- Taylor-Couette vortex flow with a low-aspect-ratio has characteristics such as the different vortex structure, because of a boundary layer of the top and bottom wall and the acceleration of the inner cylinder. In a case of large aspect ratio of Taylor Couette flow, the mechanism of the vortex like a chaotic flow has been shown by Fenstermacher and Takeda. The purpose of this study is to understand the flow mechanism with Taylor Couette system of the low-aspect-ratio using an ultrasound measurement and a numerical simulation. In this report, we mainly analyzed the process of transition to turbulent flow by using a spectra analysis in a radial and an axial direction.The Japan Society of Mechanical Engineers, 2016, The Proceedings of the Fluids engineering conference, 2016, 0508, Japanese
- Ultrasonic Velocity Profiler; UVP method is applied to various fluid flows including the multiphase flow. Most UVP measurements were carried out using the commercial measurement devices. However, a flexibility of measurements is restricted due to that fact. This article discusses development of UVP measurement system. The system consists of a pulser/receiver, an ultrasonic transducer, an analog-to-digital converter and a PC. Selection guide of hardware is provided. Velocity estimation is performed with full-digital signal processing, which eliminates complicated adjustment of analog circuits as it used to be. Typical signal processing principle and its efficient implementation are discussed. Bubbly flow measurement using this system is presented as an example of application.The Japan Society of Mechanical Engineers, 2016, The Proceedings of the Fluids engineering conference, 2016, 0507, Japanese
- A new method for high flow rate measurement using ultrasonic multi-wave pulsed Doppler method with staggered triggerUltrasonic pulsed Doppler method is a powerful tool to measure velocity distribution in a flow field. However, the method has the maximum measurable velocity. In addition, the measurement volume of this method is relatively large and it is known that the measurement volume affects measured velocities in near-wall region. To measure higher velocity, feedback method which is a dealiasing method and a multi-wave ultrasonic transducer were introduced. Using the transducer, velocities in the near-wall region were measured by 8 MHz ultrasonic with small sensor diameter, velocities far from the transducer were measured by 2 MHz ultrasonic with large sensor diameter. Thus, measurement volume was minimized in the near-wall region. Experiments were carried out at flow rate calibration facility at AIST, and the effects of the measurement volume and the number of pulse repetitions for obtaining an instantaneous velocity profile, N_The Japan Society of Mechanical Engineers, Nov. 2015, Proc. International Conference on Power Engineering-15 (ICOPE-15), 2015(12) (12), #ICOPE - 15-1040, English
, was discussed. As a result, reduction of the measurement volume improved measurement accuracy in the near-wall region by using the multi-wave transducer, and the measurement accuracy of flow rate was improved. Increasing the N_ was found to be effective for improving the measurement accuracy even though the total echo signals are the same for calculating the average velocity distribution. [Refereed]International conference proceedings - Sep. 2015, 9th International Symposium on Measurement Techniques for Multiphase Flow (9thISMTMF), 197 - 198, EnglishVisualization of water transport phenomenon in an operating PEFC in the through-plane direction[Refereed]International conference proceedings
- Sep. 2015, 9th International Symposium on Measurement Techniques for Multiphase Flow (9thISMTMF), 93 - 94, EnglishMeasurement of void fraction distribution in two-phase flow across a horizontal tube bundle by using X-ray radiography and needle contact probes[Refereed]International conference proceedings
- Sep. 2015, 9th International Symposium on Measurement Techniques for Multiphase Flow (9thISMTMF), 175 - 176, EnglishMeasurement of the condensation rate in subcooled flow boiling by spike-excitation generated multiwave ultrasound[Refereed]International conference proceedings
- The ultrasonic pulsed Doppler method (UDM) is a powerful tool for measuring velocity profiles in a pipe. However, the maximum detectable velocity is limited by the Nyquist sampling theorem. Furthermore, the maximum detectable velocity (also called Nyquist velocity), v(max), and the maximum measurable length are related and cannot be increased at the same time. If the velocity is greater than vmax, velocity aliasing occurs. Hence, the higher velocity that occurs with a larger pipe diameter, i.e. under higher flow rate conditions, cannot be measured with the conventional UDM. To overcome these limitations, dual-pulse repetition frequency (dual PRF) and feedback methods were employed in this study to measure velocity profiles in a pipe. The velocity distributions obtained with the feedback method were found to be more accurate than those obtained with the dual PRF method. However, misdetection of the Nyquist folding number using the feedback method was found to increase with the flow velocity. A feedback method with a moving average is proposed to improve the measurement accuracy. The method can accurately measure the velocity distributions at a velocity five times greater than the maximum velocity that can be measured with the conventional UDM. The measurement volume was found to be among the important parameters that must be considered in assessing the traceability of the reflector during the pulse emission interval. Hence, a larger measurement volume is required to measure higher velocities using the dual PRF method. Integrating velocity distributions measured using the feedback method with a moving average makes it possible to accurately determine flow rates six times greater than those that can be determined using the conventional pulsed Doppler method.IOP PUBLISHING LTD, Aug. 2015, MEASUREMENT SCIENCE AND TECHNOLOGY, 26(8) (8), English[Refereed]Scientific journal
- Jul. 2015, Journal of Flow Control, Measurement & Visualization, 3(3) (3), 122 - 133, English[Refereed]Scientific journal
- The principle and preliminary evaluation of a multiwave ultrasonic method for the measurement of the condensation rate in subcooled flow boilingThe condensation rate of vapor bubbles, defined by vc=-dR/dt where R is the bubble radius (assuming that bubbles have a spherical shape) and t is time, is an important parameter to determine the heat/mass transfer in the subcooled flow boiling. Accurate measurement of vc is required to improve the numerical simulation of the flow. In this study, using multiwave ultrasound, a novel method has been developed for the measurement of vc. The velocity of the top and bottom interfaces of bubbles are measured by using two measurement lines. One line has an upward direction. The other has a downward direction. From the velocity difference between the two measurement lines, vc can be calculated. By comparison with the result of the optical visualization method, the accuracy of the measured data of vc is confirmed. Using ultrasound, measurements can be carried out for opaque fluid, non-transparent flow boundaries and extreme conditions of industrial flows (e.g. high pressure, high temperature etc.). The proposed method can be highly useful to provide validation data to improve existing correlations used in numerical simulation. Consequently, the accuracy of the numerical simulation result can be improved. That is immensely important in the thermal-hydraulic analysis in nuclear engineering.May 2015, Proc. of the 23rd International Conference on Nuclear Engineering (ICONE23), 2015-January, #ICONE23 - 1868, English[Refereed]International conference proceedings
- Apr. 2015, Proc. of the 9th International Conference on Boiling Condensation Heat Transfer, EnglishDevelopment of a multiwave ultrasonic measurement method for the vapor bubble condensation rate[Refereed]International conference proceedings
- Apr. 2015, Proc. of 9th International Symposium on Fluid Flow Measurement (ISFFM), EnglishDevelopment of a Dealiasing Method in Ultrasonic Pulsed Doppler Method for Flowrate Measurement[Refereed]International conference proceedings
- 神戸大学大学院工学研究科, 2015, 神戸大学大学院工学研究科・システム情報学研究科紀要, 7, 22 - 25, Japanese
- Two measurement methods which are multiwave ultrasonic pulsed Doppler (multiwave UVP) method and wire mesh tomography (WMT) have been applied to the measurement of bubbly two-phase flow. Velocity profiles of bubbles and liquid have been measured using multiwave UVP. Simultaneously, cross-sectional void fraction distribution has been measured using WMT. As the result, a combination method has been set up. The measured parameters are indispensable in order to obtain detailed structures of two-phase flow. Multiwave UVP method exploits two basic ultrasonic frequencies which are 2 MHz and 8 MHz. Simultaneous measurement of velocity profiles of bubbles (using 2 MHz frequency) and those of liquid (using 8 MHz frequency), at the same position, is enabled. A multiwave ultrasonic transducer (multiwave TDX) which is able to emit and receive the two ultrasonic frequencies along the measurement line at the same time has been applied. The signal processing is based on the pulsed Doppler method. Using the combination method, first, instantaneous velocity profiles and void fraction distribution have been measured simultaneously for air-water counter-current bubbly flow in a vertical pipe. Flow structure has been clarified. Effect of initial condition on void fraction distribution has been confirmed. Next, measurements have been carried out for subcooled boiling bubbly flow in a vertical pipe. For measurement of subcooled boiling flow, a high temperature wire mesh sensor (WMS) has been developed. A method for separation of velocity profiles of bubbles with different sizes and velocities has been suggested. (C) 2015 The Authors. Published by Elsevier Ltd.ELSEVIER SCIENCE BV, 2015, FOURTH INTERNATIONAL SYMPOSIUM ON INNOVATIVE NUCLEAR ENERGY SYSTEMS (INES-4), 71, 337 - 351, English[Refereed]International conference proceedings
- A polymer electrolyte fuel cell (PEFC) generates electricity from an electrochemical reaction. However, water accumulation in the gas diffusion layer (GDL) reduces the cell performance. Therefore, the membrane must be kept at the appropriate humidity level for proton conduction. Hence, water management in a PEFC is essential for operation, and it is important to understand the liquid water transport phenomenon in a PEFC. In this study, to clarify the water accumulation phenomenon in the GDL under PEFC operating conditions, neutron radiography was used to visualize and measure the water distribution in the through-plane direction of a small fuel cell. The experimentally and numerically determined 2D water distributions in the through-plane direction of the membrane in the PEFC were compared. The experimental results showed that water accumulation in the GDL under the land was greater than that under the channel during early PEFC operation. Water evacuation from the GDL to the channel occurred mainly around the land corners. The water saturation distributions predicted numerically were similar to the experimental results. The water accumulation rate of the experimental results was lower than that of the numerical results at the beginning of PEFC operation. This was more apparent at a lower current density of 158 mA/cm2. The mole fraction of the vapor in the GDL under the land was higher than that under the channel, and it influenced the water accumulation in the GDL significantly.Begell House Inc., 2015, Multiphase Science and Technology, 27(2-4) (2-4), 117 - 132, English[Refereed]Scientific journal
- The ultrasonic pulsed Doppler method can be applied to obtain instantaneous velocity distribution along the ultrasonic beam path. This technique has many advantages, and it has been applied for measuring flow rate. However, the method has limitation about the measurable velocity and length. In order to overcome the limitation, a dealiasing method using staggered trigger pulse was applied for measuring velocity profile in a pipe. Furthermore, a multi-wave ultrasonic transducer was proposed for the measurement for improving the velocity measurement accuracy in the near-wall region. The applicability was examined for measuring velocity profile in a pipe with inner diameter of 200 mm. The velocity distributions were accurately obtained over the pipe by combining the velocity distributions at the basic frequency of 8 MHz for the near-wall region and 2 MHz for the region far from the transducer. As a result, it was confirmed that the flow rate measurement was improved by using the multi-wave method.American Society of Mechanical Engineers, 2015, ASME/JSME/KSME 2015 Joint Fluids Engineering Conference, AJKFluids 2015, 2A, #2015 - 10137, English[Refereed]International conference proceedings
- In order to clarify the water-accumulation phenomena in an operating polymer electrolyte fuel cell (PEFC), the water distribution in a small fuel cell was measured in the through-plane direction by using neutron radiography. The fuel cell had nine parallel channels for classifying the water-accumulation process in the gas diffusion layer (GDL) under the lands and channels. The experimental results were compared with numerical results. The water accumulation in the GDL under the lands was larger than that under the channels during the period of early PEFC operation. The difference of the water accumulation in the GDL under the land and channel was related to the water vapor. Because of the land, the vapor fraction in the GDL under the land was also higher than that under the channel. As a result, condensation was easy to occur in the GDL under the land. (C) 2015 The Authors. Published by Elsevier B.V.ELSEVIER SCIENCE BV, 2015, PROCEEDINGS OF THE 10TH WORLD CONFERENCE ON NEUTRON RADIOGRAPHY (WCNR-10), 69, 607 - 611, English[Refereed]International conference proceedings
- Visualization of water distribution in an operating PEFC in the through-plane directionA polymer electrolyte fuel cell (PEFC) generates electricity by the electrochemical reaction. It is well known that the water accumulation in the gas diffusion layer (GDL) reduces the cell performances. Hence, it is important to clarify the liquid water transport phenomenon in the PEFC. In this study, visualization of water transport phenomenon in an operating PEFC was carried out by using neutron radiography at Kyoto University Research Reactor (KUR). The two-dimensional water distributions in the through-plane of the membrane in the PEFC were compared between the experimental and the numerical results. The experimental results showed that more water accumulation was occurred in the GDL under the rib than that under the channel, and the analytical results could predict almost the same distributions in the GDL. It was found that the analytical results of water distributions were strongly influenced with the phase-change speed. Mole fraction of the vapor in the GDL under the rib was higher than that under the channel and it influenced the water accumulation in the GDL significantly.2015, ICOPE 2015 - International Conference on Power Engineering, #ICOPE - 15-1040, English[Refereed]International conference proceedings
- The ultrasonic pulsed Doppler technique known as the ultrasonic velocity profile (UVP) method has been widely used in many engineering fields. The analysis algorithms of the UVP, the number of pulse repetitions (N-pulse), noise and reflector conditions, etc. all affect the measurement accuracy. N-pulse is related to the temporal resolution, thus to improve this resolution it must be set as low as possible. However, it is known that the measurement accuracy of the instantaneous velocity becomes worse with decreasing values of N-pulse. In this study, UVP analysis algorithms including the fast Fourier transform (FFT), autocorrelation, and the wavelet transform (WT) were compared via simulations and experiments using varying values of Npulse and the signal-to-noise ratio (SNR). We show that there is an appropriate N-pulse for each algorithm that depends on the SNR; specifically, the value of N-pulse increases with decreasing SNR. The difference between the algorithms for the velocity data was small under low noise conditions. However, a FFT with a Gaussian interpolation produced the best result under noisy conditions. In contrast the WT was relatively unaffected by noise. Therefore, a WT is the preferred choice for measuring velocity distributions if high sampling measurement is not required. (C) 2014 Elsevier Ltd. All rights reserved.ELSEVIER SCI LTD, Dec. 2014, FLOW MEASUREMENT AND INSTRUMENTATION, 40, 9 - 18, English[Refereed]Scientific journal
- Aug. 2014, Proc. of the 9th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, 117 - 120, EnglishImprovement in Measurement Volume in Near-wall Region Using Ultrasonic Multi-wave Pulsed Doppler Method for Flowrate Measurement[Refereed]International conference proceedings
- Aug. 2014, Proc. of the 9th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, 113 - 116, EnglishHigher Flowrate Measurement using Ultrasonic Pulsed Doppler Method with Staggered Trigger[Refereed]International conference proceedings
- Jun. 2014, Proc. of the 16th International Symposium on Flow Visualization, Paper No. 1270, EnglishVisualization of Instantaneous Velocity profiles of Bubbles and Liquid in Gas‐Liquid Bubbly Flow using Multiwave Ultraound and Damping Effect[Refereed]International conference proceedings
- 2014, Peoc. of the 15th International Heat Transfer Conference, Paper No. IHTC15 - 9176, English[Refereed]International conference proceedings
- Sep. 2013, Journal of Japan Society of Experimental Mechanics, 13(3) (3), 277 - 284, EnglishDevelopment of Multiwave Method Using Ultrasonic Pulse Doppler Method for Measuring Two-phase Flow[Refereed]Scientific journal
- May 2013, Proc. of 8th Int. Conf. on Multiphase Flow (ICMF 2013), EnglishMeasurement of water distribution and analysis of gas-velocity distribution in an operating PEFC[Refereed]International conference proceedings
- Variable Conductance Heat Pipes (VCHP) are used as a cooling device which can passively keep the evaporating temperature by enclosing non-condensable gas (NCG) with refrigerant. The VCHP has often a bend section between evaporating and condensing area, since the condensation section should be placed vertically above the evaporation section. It is known that the bend may disturb a liquid flow to the evaporation section. The effect of the VCHP orientation, filling ratio of the refrigerant, amount of the charged NCG have been examined. A thin plate was inserted to more the effects of the bend. In this study, the refrigerant behaviors in the VCHP with the bend were diagnosed based on flow visualization by neutron radiography. It was observed that liquid plugs formed at the bend and suppressed the condensed liquid supply to the evaporating section without the thin plate. It was also shown that the thin plate inserted in the bend was effective to avoid the liquid plug formation.日本伝熱学会, Apr. 2013, 日本伝熱学会論文集, 21(2) (2), 59 - 66, Japanese[Refereed]Scientific journal
- 2013, Vietnam Journal of Mechanics, 35(3) (3), 239 - 256, EnglishMeasurements of single-phase and two-phase flow in a vertical pipe using ultrasonic pulse Doppler method and ultrasonic time-domain cross-correlation method[Refereed]Scientific journal
- Ultrasonic pulse Doppler method has been widely used in many engineering field referred to as UVP (ultrasonic velocity profiler). Analysis algorithm in the UVP, number of pulse repetition (Npulse), noise and reflector conditions, etc. may affect on the measurement accuracy. The Npulse is related to the temporal resolution, and must be set as low as possible in order to improve the temporal resolution. However, it is known that accuracy of instantaneous velocity becomes worse with decreasing of the Npulse. In this study, effect of analysis algorithm in the UVP on velocity data was investigated with changing of the Npulse and SNR by simulation and experiments. As a result, it is shown that there is an appropriate N pulse in each algorithm depending on the SNR. An algorithm which decides the Doppler frequency from maximum value in the power spectrum, FFT-max, was relatively hard to be affected by noise. Difference of velocity standard deviation was small between lower and higher noise conditions when FFT-max with Npulse over the appropriate value was used for the calculation. Hence, FFT-max was the best analysis algorithm for measuring flow field compared with the autocorrelation. ©2013 The Japan Society of Mechanical Engineers.Japan Society of Mechanical Engineers, 2013, Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 79(799) (799), 356 - 367, Japanese[Refereed]Scientific journal
- Water distributions of a polymer electrolyte fuel cell (PEFC) with 9-parallel channels during operation were visualized using a neutron radiography facility at 84 port in KUR (Kyoto University Research Reactor). An imaging system with a neutron image intensifier (I.I.) was employed for reducing the exposure time, and the water distributions in the in-plane and through-plane directions in the PEW. were alternately obtained every 20 sec. The accumulation processes from the GDL to the channels were confirmed. Water accumulated in the GDL at the cathode and evacuation into the channels started around 5 min Water tended to accumulate at the edge of the ribs, and accumulated as water drops in the channels. The size of the water drops grew up to 1 mm which was the same size as the channel width and height, and the cell voltage was decreased because the liquid drops disturbed the air supply. (C) 2013 The Authors. Published by Elsevier B.A..ELSEVIER SCIENCE BV, 2013, 7TH INTERNATIONAL TOPICAL MEETING ON NEUTRON RADIOGRAPHY (ITMNR-7), 43, 277 - 281, English[Refereed]International conference proceedings
- Hydrogen gas and air are supplied to a polymer electrolyte fuel cell (PEFC). The air and the hydrogen form water and condensation may occur in the cathode side. The generated water may affect the fuel cell performance because of blocking the oxygen from reaching cathode reaction area. An imaging system with a neutron image intensifier (NII) was used for visualizing the water behaviour in the PEFC. The water distributions in the proton exchange membrane (PEM) and the gas diffusion layers (GDL) were measured by the imaging system. Visualization experiments were performed during the PEFC operation in order to clarify the water distributions in the experiments with different utilization. The generated water was discharged into the channel after the amount of water thickness in the GDL increased to a certain value of about 600 mu m in thickness in the through-plane direction. The discharged water formed water drops in the channel. The effects of the water drops in the channel on the fuel cell performance could be observed clearly. It was shown that the cell voltage increased when the water was evacuated. (C) 2013 The Authors. Published by Elsevier B.V.ELSEVIER SCIENCE BV, 2013, 7TH INTERNATIONAL TOPICAL MEETING ON NEUTRON RADIOGRAPHY (ITMNR-7), 43, 288 - 293, English[Refereed]International conference proceedings
- Sep. 2012, Proc. of 8th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, 105 - 108, EnglishEffects of analysis algorithms and number of repetition pulses on velocity data by using ultrasonic Doppler method[Refereed]International conference proceedings
- Jun. 2012, Proc. of 7th Int. Topical Meeting on Neutron Radiography (ITMNR-7), 58, EnglishVisualization of water behavior in in-plane and through-plane directions of a PEFC using a color image intensifier[Refereed]International conference proceedings
- Jun. 2012, Proc. of 7th Int. Topical Meeting on Neutron Radiography (ITMNR-7), 39, EnglishMeasurements of water distributions in the through-plane direction of a PEFC using a neutron color image intensifier[Refereed]International conference proceedings
- Mar. 2012, 実験力学, 13(1) (1), 3 - 12, Japanese超音波流速分布計測法と気液二相流計測への応用[Refereed]Scientific journal
- We have many demands to understand flow phenomena in many industrial applications. Detecting the gas-liquid interface is important when measuring velocities in two-phase flow or in an open channel. We want to obtain velocity distributions two dimensionally, also. To extend the applicability, many techniques utilizing the ultrasonic Doppler velocity profiler (UVP) have been recently developed. This chapter shows these extended techniques. Liquid and gas velocity distributions are obtained simultaneously using a multi-wave transducer are described in Sect. 7.1. Techniques detecting a gas-liquid interface depending on fluid interface relative to the ultrasonic wavelength are presented in Sect. 7.2. The UVP is utilized for measuring void fraction distributions in Sect. 7.3. Section 7.4 shows a technique measuring two-dimensional velocity components. A new approach for improving temporal resolution using the ultrasonic correlation method is presented in Sect. 7.5.2012, Fluid Mechanics and its Applications, 101, 227 - 262, English[Refereed]Scientific journal
- Because of the advantages of the ultrasonic velocity Doppler profiler (UVP), namely in spatiotemporal velocity field measurements and in its applicability for opaque liquids, UVP has a wide field of application in science and industry. The following chapter introduces carefully selected examples of applications covering relatively basic areas of application. The focus of the contents in this chapter is categorized into (1) studies of flow instability and transition (Sect. 5.1), (2) measurements and investigations of liquid metal flows (Sect. 5.2), (3) developments of new rheometry (Sect. 5.3), (4) determinations of rheological properties (Sect. 5.4), (5) studies of magnetic fluids (Sect. 5.5) and (6) gas-liquid two-phase flow (Sect. 5.6), (7) measurements of flowrate in turbidity flows (Sect. 5.7), and (8) -determinations of flows in a deforming tube for biomedical applications (Sect. 5.8). The measurement and post-processing techniques used in this chapter are described in detail in Chaps. 4 and 7, and, detailed explanations of these aspects are omitted in this chapter.2012, Fluid Mechanics and its Applications, 101, 107 - 200Scientific journal
- The ultrasonic velocity profiler (UVP) mainly employs the ultrasonic Doppler method to obtain a one-dimensional velocity profile. The measurement position is a function of time-of-flight of the ultrasonic pulses, and the velocity is obtained from the Doppler shift frequency. The principle and the method to detect the Doppler shift frequency are described in Sect. 3.1. When we use UVP for measuring velocity profiles in real situation, selections of the ultrasonic basic frequency, transducer setting, and ultrasonic reflectors are important, as shown in Sect. 3.2. Attention to be paid for measuring velocity is described in Sect. 3.3. Velocity aliasing appears if the velocity is over the maximum velocity defined by the Nyquist sampling theorem. We have to set a transducer carefully to avoid multiple reflections from surroundings. Temperature directly affects the measurement accuracy because measurement positions and velocities are functions of sound speed, and we also have to pay attention to the effects of solid boundary and measurement volume.2012, Fluid Mechanics and its Applications, 101, 43 - 69, English[Refereed]Scientific journal
- THREE-DIMENSIONAL VISUALIZATION OF WATER BEHAVIOR IN POLYMER ELECTROLYTE FUEL CELL BY USING NEUTRON RADIOGRAPHYVisualization of dynamic three-dimensional water behavior in a PEFC stack was carried out by neutron CT using a neutron image intensifier for clarifying water effects on performances of a Polymer Electrolyte Fuel Cell (PEFC) stack. Neutron radiography system at JRR-3 in Japan Atomic Energy Agency was used. An operating stack with three cells based on Japan Automobile Research Institute standard was visualized. A consecutive CT reconstruction method by rotating the fuel stack continuously was developed by using a neutron image intensifier and a C-MOS high speed video camera. The dynamic water behavior in channels in the operating PEFC stack was clearly visualized 15 sec in interval by the developed dynamic neutron CT system. From the CT reconstructed images, evaluation of water amount in each cell was carried out. It was shown that the water distribution in each cell was correlated well with power generation characteristics in each cell.AMER SOC MECHANICAL ENGINEERS, 2012, PROCEEDINGS OF THE ASME POWER CONFERENCE - 2011, VOL 2, #POWER2011-55381, 427 - +, English[Refereed]International conference proceedings
- Visualization of dynamic three-dimensional water behavior in a polymer electrolyte fuel cell (PEFC) stack was carried out by neutron CT using a neutron image intensifier. The neutron radiography system at JRR-3 in Japan Atomic Energy Agency was used. An operating stack with three cells based on Japan Automobile Research Institute standard was visualized. A consecutive CT reconstruction method by rotating the fuel stack continuously was developed using a neutron image intensifier and a C-MOS high speed video camera. The dynamic water behavior in channels in the operating PEFC stack was clearly visualized in 15 s intervals by the present dynamic neutron a system. (C) 2011 Elsevier B.V. All rights reserved.ELSEVIER SCIENCE BV, Sep. 2011, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 651(1) (1), 277 - 281, English[Refereed]Scientific journal
- A capillary tube is often used as a throttle for a refrigerating cycle. Subcooled refrigerant usually flows from a condenser into the capillary tube. Then, the refrigerant is decompressed along the capillary tube. When the static pressure falls below the saturation pressure for the liquid temperature, spontaneous boiling occurs. A vapor-liquid two-phase mixture is discharged from the tube. In designing a capillary tube, it is necessary to calculate the flow rate for given boundary conditions on pressure and temperature at the inlet and exit. Since total pressure loss is dominated by frictional and acceleration losses during two-phase flow, it is first necessary to specify the boiling inception point. However, there will be a delay in boiling inception during decompressed flow. This study aimed to clarify the boiling inception point and two-phase flow characteristics of refrigerant in a capillary tube. Refrigerant flows in a coiled copper capillary tube were visualized by neutron radiography. The one-dimensional distribution of volumetric average void fraction was measured from radiographs through image processing. From the void fraction distribution, the boiling inception point was determined. Moreover, a simplified CT method was successfully applied to a radiograph for cross-sectional measurements. The experimental results show the flow pattern transition from intermittent flow to annular flow that occurred at a void fraction of about 0.45. (C) 2011 Elsevier B.V. All rights reserved.ELSEVIER SCIENCE BV, Sep. 2011, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 651(1) (1), 258 - 263, English[Refereed]Scientific journal
- Fuel gas (hydrogen gas) and oxidant gas (air) are supplied to a polymer electrolyte fuel cell (PEFC). Protons pass through the electrolyte membrane, and combine with oxygen to form water in the cathode reaction site. The generated water must be supplied appropriately to the membrane for proton conduction. On the other hand, the generated water may affect the fuel cell performances because of the blocking of oxygen from reaching the cathode reaction site. Therefore, water management in the PEFC is important, and water distribution during the operation in the through-plane direction has been of wide concern. In order to obtain the water distributions in a membrane electrode assembly (MEA) and a gas diffusion layer (GDL), a borescope system was newly employed using neutron radiography. The system could obtain the water distribution in the MEA and the GDL, and pixel size of 6.5 mu m was achieved. Furthermore, the system was applied for a tilted converter system. The pixel of 1.0 mu m at an angle of 81 degrees was achieved, and improvement of the spatial resolution was confirmed. (C) 2010 Elsevier B.V. All rights reserved.ELSEVIER SCIENCE BV, Sep. 2011, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 651(1) (1), 286 - 289, English[Refereed]Scientific journal
- Fuel gas (hydrogen gas) and oxidant gas (air) are supplied to a polymer electrolyte fuel cell (PEFC). Condensation may occur in the cathode side, since the air might be super-saturated by the fuel cell reactions. If condensed water exists in a gas diffusion layer (GDL) or the gas channels, it may affect the fuel cell performances because it blocks the oxygen from reaching the cathode reaction site. Thus, water management in the PEFC is important. In order to clarify water effects on performances of a PEFC, visualization and quantitative measurements of water distributions in a PEFC were carried out by means of neutron radiography. Two-dimensional water distributions were obtained, and water ejection was confirmed. It was found that the water easily accumulated in the GDL under the rib rather than under the channel at beginning of the operation. Furthermore, a network analysis of gas-velocity distribution is applied for the experimental results. It analyzes the gas-velocity distributions depending on the flow resistance, which is the pressure drop. Applying the measured data of water thickness, gas-velocity distributions were obtained in the channel and the GDL. From the calculation, air supply in the GDL dramatically decreased with increasing of water accumulation. (C) 2010 Elsevier B.V. All rights reserved.ELSEVIER SCIENCE BV, Sep. 2011, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 651(1) (1), 290 - 296, English[Refereed]Scientific journal
- Neutron radiography is one of the useful tools for visualizing water behavior in operating fuel cells. In order to observe the detailed information about the water distribution in membrane electrode assembly (MEA) and gas diffusion layer (GDL) in fuel cells, a high performance neutron imaging system is required. A neutron color image intensifier (NCII) is a high spatial resolution and high sensitivity neutron image detector. We have developed an imaging system using an NCII for visualizing the behavior of water in fuel cells. The pixel size of the imaging system is around 4.7 mu m in the small view field. By using this system, water distribution of a small sized fuel cell was observed continuously every 20 s at the Thermal Neutron Radiography Facility (TNRF). In the results, the water area appears from the GDL and MEA regions, and expanded to the cathode side channel with time. However, the voltage was gradually reduced with time, and steeply dropped. It is considered that the reduction and the drop of voltage were caused by a blockage of gas flow due to accumulation of water in the GDL and the gas flow channel in the cathode side. (C) 2011 Elsevier B.V. All rights reserved.ELSEVIER SCIENCE BV, Sep. 2011, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 651(1) (1), 268 - 272, English[Refereed]Scientific journal
- A Variable Conductance Heat Pipe (VCHP) is used as a cooling device for electrical equipments. The condensation area is passively controlled by the non-condensable gas volume in the VCHP depending on the heat load. The VCHP has often a bent pipe between the evaporation and condensation area. The heat pipe performance depends much on the bent pipe shape and configuration because a liquid plug is formed in the bent pipe and disturbs the refrigerant circulation. However, the mechanism has not been clarified well. The neutron radiography system at the JRR-3 in Japan Atomic Energy Agency (JAEA) was used to visualize the refrigerant behavior in the VCHP. Effects of the thin plate inserted in the pipe, refrigerant filling ratios and heat pipe configuration were examined on the heat pipe performance. The liquid plug was formed at the bend and caused to decrease the performance. It was confirmed that the thin plate insert was effective to disturb the liquid plug formation. (C) 2011 Elsevier B.V. All rights reserved.ELSEVIER SCIENCE BV, Sep. 2011, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 651(1) (1), 264 - 267, English[Refereed]Scientific journal
- Aug. 2011, Proc. of Int. Conf. on Advanced Technology in Experimental Mechanics 2011 (ATEM’11), pp.288, EnglishQuantitative Measurements of Water Distribution in a PEFC by using Neutron Radiography and Analysis of Gas-velocity Distributions[Refereed]Scientific journal
- An ultrasonic velocity profile (UVP) method can measure instantaneous one-dimensional velocity profile along the measuring line. It is non-intrusive technique, and it can be easily applied for existing facilities. The UVP method utilizes the ultrasonic Doppler frequency reflected on tracer particles for obtaining the velocity. For analyzing the Doppler frequency, there are some algorithms such as Fast Fourier Transform (FFT), auto-correlation, and so on. However, the influence of the algorithms on measuring velocity profile has not been investigated. In this study, difference of the algorithms for velocity measurements was investigated using a developed system. It consists of an ultrasonic pulser-receiver which transmits and receives ultrasonic waves, a high-speed digitizer which records wave data, and a PC which analyzes and calculates velocity. FFT and auto-correlation method were used for the calculation. In case of the FFT, there are 2 methods to calculate the Doppler frequency. One is a method to calculate the frequency of maximum value in the power spectral density (PSD), and the other is a method to calculate the average value of the frequency in the PSD. Velocity distributions were compared to a laser Doppler velocimeter (LDV), and the appropriate algorithms were chosen depending on the flow conditions. From the results, it was clarified that the auto-correlation method could reduce the number of ultrasonic repetition for the measurement. Copyright © 2011 by ASME.2011, ASME-JSME-KSME 2011 Joint Fluids Engineering Conference, AJK 2011, 1(D) (D), 2773 - 2780, English[Refereed]International conference proceedings
- A dynamic CT system was developed for visualization of consecutive three-dimensional water behavior in a PEFC stack for neutron radiography. The system is composed of a neutron image intensifier and a C-MOS high speed video camera. An operating stack with three cells based on the Japan Automobile Research Institute standard was visualized using the neutron radiography system at a research reactor JRR-3 in Japan Atomic Energy Agency. The dynamic water behavior in channels in the operating PEFC stack was clearly visualized every 15 seconds by using the system. The water amount in each cell was evaluated by the CT reconstructed images. It was shown that a cell voltage decreased gradually when the water increased and increased rapidly when the water was evacuated. It was estimated that the power generation stopped when the channel of a cell was partly filled with the water because the air supply was blocked to a cell in the stack. © 2011 The Japan Society of Mechanical Engineers.2011, Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 77(784) (784), 2255 - 2262, Japanese[Refereed]Scientific journal
- Jun. 2010, Proc. of 7th International Conference on Multiphase Flow, #2.6.1, EnglishMeasurement of Water Thickness by using Neutron Radiography and Simulation of Gas-Velocity Distribution in a PEFC[Refereed]Scientific journal
- Apr. 2010, Proc. of 7th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, pp.71-74, EnglishIdentification of liquid-gas interface based on ultrasonic reflected signal for two-phase flow velocity measurement[Refereed]Scientific journal
- 2010, KURRI Progress Report, 113 - 113, EnglishStudies on Boiling Two-phase Flow by Neutron Radiography
- Water behavior in an operating polymer electrolyte fuel cell (PEFC) was visualized by using neutron radiography, and the cell voltage and the pressure drop between the inlet and outlet of air were simultaneously measured. The PEFC is compliant with Japan Automobile Research Institute (JARI) standard PEFCs. An electrode area of 50×50 mm2 was visualized, and the cell temperature was kept at 80°C. The effects of channel geometry, i.e., single- and triple-serpentine, relative humidity of air, and current density, were investigated. From the experiments, it can be confirmed that fluctuation of area-average water thickness in a triple-serpentine channel is larger than that in a single-serpentine channel, and water in the channel is likely to accumulate at corners of the channel in the single- serpentine channel. Furthermore, movement of condensed water is strongly related to cell voltage and pressure drop. For a few minutes after the operation, the average thickness of water at the rib is thicker than that at the channel. Furthermore, a network modeling to predict the gas-velocity distributions was proposed. Based on the water depth in the channel and the gas diffusion layer, gas-velocity distributions were obtained. The pressure drops in single-phase flow were in good agreement with the experimental results under low gas-flow rate. The model could predict the pressure drop based on the water thickness in the PEFC. © 2010 by Begell House, Inc.2010, Multiphase Science and Technology, 22(1) (1), 57 - 78, English[Refereed]Scientific journal
- Velocity profile measurements in bubbly flows have been performed by using the ultrasonic velocity profile technique, which can measure velocity distributions along a measuring line. To obtain the liquid and gas velocity distributions simultaneously, a new technique for separating liquid and gas velocity data is developed. The technique employs a unique ultrasonic transducer (TDX) referred to as a multi-wave transducer. The multi-wave TDX consists of two kinds of ultrasonic piezoelectric elements that are concentrically set and have different resonant frequencies. The central element of 3mm diameter has a basic frequency of 8MHz for liquid-phase measurements, and the outer element has a basic frequency of 2MHz for bubble-phase measurements in two-phase bubbly flows. The multi-wave TDX can emit the two ultrasonic frequencies independently. First, the multi-wave TDX is used together with an ultrasonic velocity profiler (UVP) based on the ultrasonic pulse repetition method. The effects due to volume, liquid velocity, and bubble rising velocity measurements are obtained by the UVP in two-phase bubbly flows. However, the velocity distribution of bubbles measured by the UVP includes errors induced by tracer particles suspended in the liquid. The ultrasonic velocity profile technique requires tracer particles as ultrasonic reflectors. Then to improve the accuracy of the bubble rising velocity distribution, the ultrasound time domain correlation (UTDC) method is applied. Comparing the intensities of echo signals from 2MHz and 8MHz ultrasounds, bubble and liquid velocity distributions were obtained. The velocity distributions measured by the UTDC are in good agreement with those measured by the UVP. This technique can be utilized for many industrial applications.TAYLOR & FRANCIS INC, 2010, CHEMICAL ENGINEERING COMMUNICATIONS, 197(2) (2), 114 - 133, English[Refereed]Scientific journal
- A self-vibration heat pipe having a meandering capillary tube can operate on top and horizontal heat mode without gravity effects. However, the behaviors of the working fluid in the pipe have not been well studied. In this study, the working fluid in the self-vibration heat pipe was visualized by neutron radiography system in Japan Atomic Energy Agency. The liquid columns formed in the cooling area were visualized at 200 frames/s in the meandering channel. Image processing methods to show the vibration of the liquid column were developed. It was shown that the liquid columns were vibrated around the cooling area and supplied to the heating area. The heat was transported from the heating area to the cooling area. The maximum effective thermal conductivity of the plates were about 20 times of aluminum. The flow pattern was evaluated at the volumetric ratio of liquid phase in the heat pipe. The periods of the vibration were predicted fairly well by a mass-spring model.Japan Society of Mechanical Engineers, 2010, Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 76(766) (766), 975 - 982, Japanese[Refereed]Scientific journal
- Neutron radiography is suitable for the visualization of liquid behavior in a metallic machine. Observation of oil behavior in a small 4-cycle engine on operating was carried out by using the neutron radiography facility at JRR-3 in JAEA. The engine was not fired but operated by an electrical motor. Movies were taken by a neutron image intensifier with a color CCD camera of 8-bit resolution, 30 frames/s and 640 x 480 pixels developed by Toshiba Corp. The engine was placed on a turn table and was rotated, so the movie could be taken from any angle. Numbers of revolution of the engine were changed from 260 to 1200 rpm. Visualized images of the mechanism and the oil behavior in the engine were obtained. (C) 2009 Elsevier B.V. All rights reserved.ELSEVIER SCIENCE BV, Jun. 2009, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 605(1-2) (1-2), 204 - 207, English[Refereed]Scientific journal
- A polymer electrolyte fuel cell (PEFC) consists of a membrane electrode assembly (MEA), gas diffusion layers (GDL), hydrogen and oxygen supply channels. At the anode, protons and electrons are generated, while at the cathode the protons and electrons combine to form water. The condensed water may affect the fuel cell performance. In order to clarify the effect of water distribution on the PEFC performance, three-dimensional water distribution in the PEFC was visualized by using a neutron radiography facility at JRR-3 in JAEA. For observing the detailed water distribution, a small sized PEFC was designed. Size of the gas channel is 1 mm width and 0.5 mm depth. Thickness of the MEA and the GDL are about 50 and 200 mu m. The electrode area is 0.35 x 3.5 cm(2). The PEFC was set on an automatic rotating stage, and a picture was taken every 2.25 degrees by using a cooled CCD camera with grey scale of 16 bit. The exposure time was set at 15 s. Using the 80 pictures which correspond to 180 degrees, a computed tomography (CT) was carried out. In order to observe water distribution with high spatial resolution, the LiF scintillator with a thickness of 50 mu m was used. From the water distributions parallel and perpendicular to the MEA, existence of water around O-ring can be confirmed. However, the detailed distribution in the PEFC is difficult to obtain from the two-dimensional pictures. On the other hand, CT pictures make possible to obtain the three-dimensional water distribution. In this study, the spatial resolution of 76.5 mu m was achieved, and existence of water in the PEFC could be confirmed. (C) 2009 Elsevier B.V. All rights reserved.ELSEVIER SCIENCE BV, Jun. 2009, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 605(1-2) (1-2), 131 - 133, English[Refereed]Scientific journal
- Heat generation density of electric elements increases close to the limit of forced air-cooling. New cooling technology is required and a self-vibration heat pipe is proposed for the electric elements cooling. The self-vibration heat pipe, which has a meandering capillary channel, can operate for vertical and horizontal heat removal without gravity effects. However, the behaviors of the working fluid in the pipe have not been well studied. The purpose of this study is to clarify the working fluid phenomena in the heat pipe. The working fluid in the pipe was visualized by neutron radiography system at JRR-3 in Japan Atomic Energy Agency. The liquid columns in the meandering channel of the heat pipe were recorded by a highspeed camera. The obtained images were segmented and the meandering capillary channel was uncoiled by image processing methods to show the temporal vibration of the liquid columns in the stretched channel. Periods of the column oscillation were about 0.5-1.5 s. The oscillation of the columns was analyzed by a mass-spring model. The periods of the oscillation were obtained and compared with the experiment results. It was shown that the analytical values agreed fairly with the experimental ones. (C) 2009 Elsevier B.V. All rights reserved.ELSEVIER SCIENCE BV, Jun. 2009, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 605(1-2) (1-2), 200 - 203, English[Refereed]Scientific journal
- In order to clarify the effects of water on performances of a Polymer Electrolyte Fuel Cell (PEFC), measurements of water distribution in a Japan Automobile Research Institute (JARI) standard PEFC Were carried out by means of neutron radiography. Furthermore, the cell voltage and the pressure drop between inlet and outlet of the air were simultaneously measured. The effects of channel geometry, i.e. single-serpentine and three-serpentine, and relative humidity of air were investigated. The experimental conditions were current density of 200 mA/cm(2), hydrogen utilization of 9.5% and oxygen utilization of 40%. The membrane electrode assembly (MEA) area was 5 x 5 cm(2). The pictures were taken every 15 s with an exposure time of 12 s. The spatial resolution was 108 mu m. From the measurements, the relation between cell voltage, pressure drop and movement of the water plug in the channel was confirmed. The PEFC performances were recovered as the water plug evacuated. Condensed water in the channel decreased with the relative humidity of air. However, it may affect the MEA permanence. Therefore, the most appropriate operating conditions should be decided for taking into account both the cell performances and the permanencies. (C) 2009 Elsevier B.V. All rights reserved.ELSEVIER SCIENCE BV, Jun. 2009, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 605(1-2) (1-2), 127 - 130, English[Refereed]Scientific journal
- Visualization and Measurement of Water Behavior in PEFC by using Neutron RadiographyIn this study, water behavior in an operating PEFC was visualized by using neutron radiography, and the cell voltage and the pressure drop between inlet and outlet of air were simultaneously measured. The PEFC is compliant with JARI (Japan Automobile Research Institute) standard PEFC. Electrode area with 50x50 mm(2) was visualized, and the cell temperature was kept at 80 degrees C. The effect of geometry, i.e. single-serpentine and three-serpentine, relative humidity of air and current density were investigated. From the experiments, it can be confirmed that fluctuation of area-average water thickness in three-serpentine channel is larger than that in single-serpentine channel and water in the channel is likely to accumulate at corners of the channel in single-serpentine channel. Furthermore, movement of condensed water is strongly related with the cell voltage and the pressure drop.JAPAN SOC MECHANICAL ENGINEERS, 2009, PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON POWER ENGINEERING 2009 (ICOPE-09), VOL 2, 2, pp.225-230, 225 - 230, English[Refereed]International conference proceedings
- The Japan Society of Fluid Mechanics, Aug. 2008, ながれ, Vol.27、No.4、pp.283-294(4) (4), 283 - 294, JapaneseScientific journal
- Jun. 2008, Proceedings of 2008 International Congress on Advances in Nuclear Power Plants, Paper No. 8012, EnglishMultidimensional Analysis of Developing Two-phase Flows in an ESBWR Chimney with and without Riser Channels[Refereed]International conference proceedings
- For the purpose of accurate flow measurement, an automatic three-dimensional (3D) sound field measurement system has been developed, and an experimental study has been conducted on ultrasonic properties. By using this system, ultrasonic sound pressure distributions and radiation angles in water have been measured. According to Snell's law, the ultrasonic transmission properties can be obtained on the basis of incidence angle, acoustic impedance, basic frequency of ultrasound, and material and thickness of the metallic plate. However, this law cannot be applied to certain cases where an ultrasonic incident wave passes through a metallic plate and turns into a longitudinal wave, a shear wave and a Lamb wave. Consequently, the ultrasonic propagation paths have been investigated experimentally at various angles of incidence. From the experiments, it was confirmed that the ultrasonic beam paths change with incidence angles. Hence, the most suitable incidence angle has been determined from the result of measurements. Velocity measurements using an ultrasonic velocity profiler were made at various incidence angles. The accuracy of measuring flow rates changed with the incidence angles. The optimal incidence angle determined from 3D field measurements was found to yield the most accurate flow rates. (c) 2007 Elsevier Ltd. All rights reserved.ELSEVIER SCI LTD, Jun. 2008, FLOW MEASUREMENT AND INSTRUMENTATION, 19(3-4) (3-4), 223 - 232, English[Refereed]Scientific journal
- This paper proposes a measurement technique for two-phase bubbly and slug flows using ultrasound. In order to obtain both liquid and gas velocity distributions simultaneously, a new technique for separating liquid and gas velocity data is developed. The technique employs a unique ultrasonic transducer referred to as multi-wave transducer (TDX). The multi-wave TDX consists of two kinds of ultrasonic piezoelectric elements which have different resonant frequencies. The central element of 3 mm diameter has a basic frequency of 8 MHz and the outer element has a basic frequency of 2 MHz. The multi-wave TDX can emit the two ultrasonic frequencies independently. In our previous investigations, both elements were connected with two ultrasonic velocity profile (UVP) monitors to measure liquid and bubble velocity distributions. However, the technique was limited to the measurement of bubbly flows at low void-fraction. Furthermore, it was impossible to synchronize the instantaneous velocities of liquid and bubbles because of the facility limitation. In order to overcome these disadvantages, cross-correlation method is employed for the measurements in this study. In order to apply the technique to flow measurements, ultrasound pressure fields are measured. As a result, it is found that the TDX must be set 20 mm away from the test section. The technique is applied to measuring bubbly and slug flows. By the combination of 2 and 8 MHz ultrasonic echo signals, the echo signals are distinguished between reflected from particles and bubbles. Compared with the results of obtaining with the multi-wave method and a high-speed camera, it is confirmed that the technique can separate the information of liquid and gas phases at a sampling rate of 1000 Hz. (c) 2007 Elsevier Ltd. All rights reserved.ELSEVIER SCI LTD, Jun. 2008, FLOW MEASUREMENT AND INSTRUMENTATION, 19(3-4) (3-4), 205 - 213, English[Refereed]Scientific journal
- Application of ultrasonic time-domain correlation method to two phase flow measurementsHere, the authors focus on two-phase flow measurement using ultrasound. Previously, we developed a way to measure bubbly flow using UVP. By this method, we are able to separate liquid information from bubbles information to some degrees. However, when the bubble number density is low a problem occurs, because the effect of liquid information is strong under that condition. From this fact, we applied the ultrasound time domain correlation method (UTDC) to two-phase flow measurement. This method is our original technique to measure the velocity distribution. It is based on the cross-correlation between two consecutive echoes of ultrasonic pulses. With this method, we can separate liquid information from bubble information even when the bubble number density is low, because reflected signals depend on the size of reflectors and the frequency of ultrasound. In this study, the authors applied the UTDC methods to rectangular channel using a multi-wave ultrasonic transducer (TDX). The multi-wave TDX has two kinds of basic frequencies. One is 2MHz for the velocity of rising bubbles and the other is 8MHz for the liquid velocity. So, it enables us to measure the velocity of the liquid and that of bubbles at the same point and time.Sep. 2007, Proceedings of 5th World Congress on Industrial Process Tomography, CD-ROM#MFI19, 810 - 815, English[Refereed]International conference proceedings
- Velocity profile measurements of two-phase flow in rectangular channel using ultrasonic time-domain correlation methodVelocity measurement using ultrasound has attracted much attention in engineering fields and medical science field. Especially, Ultrasonic velocity profile monitor (UVP) has been in the spotlight in engineering fields, because of its many diagnostic advantages. The major advantage is that UVP can obtain instantaneous velocity distributions on beam line by measuring Doppler shift frequencies of echo signals. And UVP is applicable to existing pipes, because it is non-contact measurement technique. In recent years, various studies about UVP have been done, and UVP has already been put to practical use in engineering plants. The authors especially focused on two-phase flow measurement using ultrasound. Previously, we developed a way to measure bubbly flow using UVP. By this method, we are able to separate liquid information from bubbles information to some degrees. However, when the bubble number density is low, a problem occurs. Because the effect of liquid information is strong under that condition. From this fact, we applied the ultrasound time domain correlation method (UTDC) to two-phase flow measurement. This method is our original technique to measure the velocity distribution. It is based on the cross-correlation between two consecutive echoes of ultrasonic pulses. With this method, we can separate liquid information from bubble information even when the bubble number density is low, because reflected signals depend on the size of reflectors and frequency of ultrasound. In this study, the authors applied the UTDC to two-phase flow measurements in rectangular channel using a multi-wave ultrasonic transducer (TDX). The multi-wave TDX has two kinds of basic frequencies. One is 2MHz for the velocity of rising bubbles and the other is 8MHz for the liquid velocity. So it enables us to measure the velocity of the liquid and that of bubbles at the same point and time. The 2MHz ultrasonic element of TDX has 10mm diameter and the 8MHz ultrasonic element has 3mm diameter.AMER SOC MECHANICAL ENGINEERS, 2007, FEDSM 2007: PROCEEDINGS OF THE 5TH JOINT AMSE/JSME FLUIDS ENGINEERING SUMMER CONFERENCE VOL 1, PTS A AND B, CD-ROM#FEDSM2007-37072, 707 - 714, English[Refereed]International conference proceedings
- Lead, The Visualization Society of Japan, Oct. 2006, The Visualization Society of Japan, 26(103) (103), 10 - 17, Japanese
- Measurement of two-phase flow using multi-wave ultrasonic (Measurement of bubble rising velocity using correlation method)In this paper, two types of ultrasonic measurement techniques are attempted to obtain liquid and gas velocity distributions in bubbly flow. The first attempt is that the both of liquid and gas velocity distributions are obtained using an ultrasonic basic frequency and its echo signals. In order to separate the signals reflected on liquid-gas interfaces and particles, thresholding based on the ultrasonic echo intensity is applied. However, it is difficult to extract completely the echo signals reflected on the tracer particles. In order to overcome the difficulty, a multi-wave ultranonic transducer (TDX) is applied. The TDX consisted of two piezoelectric elements that have different basic frequency. The liquid velocity distribution is obtained using an ultrasonic velocity profiles (UVP) monitor at 8 MHz ultrasonic frequency, and the rising velocity of bubbles is measured using cross-correlation method at 2 MHz ultrasonic frequency. Using the technique, both of the liquid and gas velocity distributions are obtained accurately using the TDX.The Japan Society of Mechanical Engineers, Oct. 2006, Transactions of the Japan Society of Mechanical Engineers Series B, Vol.72, No.722, pp.135-142(722) (722), 2465 - 2472, Japanese[Refereed]Scientific journal
- Sep. 2006, Proceedings of 5th International Symposium on ultrasonic Doppler method for fluid mechanics and fluid engineering, pp.23-26, EnglishApplication of ultrasonic multi-wave method for multi-phase flow[Refereed]International conference proceedings
- This paper proposes a new measurement technique for multi-phase flow using correlation and multi-wave method. The authors developed a unique ultrasonic transducer named as multi-wave TDX. The TDX consists of a special ultrasonic element having two basic ultrasonic frequencies. The central 3 mm diameter area has a basic frequency of 8 MHz and the outer area has a basic frequency of 2 MHz. The TDX can emit the two ultrasonic frequencies independently. Using the two ultrasonic wave lengths, signals of two basic frequencies can be obtained at the same time. Comparing with the each echo signal, the signal combination can be classified into 3 groups. Hence, applying ultrasonic correlation method (UTDC) and the signal comparison method for multi-wave method, bubble rising velocity and liquid velocity distribution can be obtained simultaneously.THE JAPANESE SOCIETY FOR MULTIPHASE FLOW, Apr. 2006, Progress in Multiphase Flow Research, Vol.1, pp.17-23, 17 - 23, Japanese[Refereed]Scientific journal
- Oct. 2005, Proceedings of The 11th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, CD-ROM#379, EnglishDevelopment of two-phase flow measurement technique using multi-wave ultrasonic transducer[Refereed]International conference proceedings
- In this paper, a new technique for multi-phase flow measurement is proposed. This technique is based upon an ultrasonic Doppler method (UDM). Using different sizes of ultrasonic transducers (TDXs) for the UDM measurement, the measured data apparently differ. With a change in the measurement volume, the velocity PDF significantly changes. Applying this method for multi-phase flow, several types of particles whose sizes are considerably different can be obtained for each velocity distributions. To obtain each velocity at the same time and at the same position, a new Multi-wave TDX is developed. Using the Multi-wave TDX, this method was utilized for the measurement of bubbly flow in vertical pipe. To confirm the accuracy of each velocity distribution, the velocity PDFs were calculated. The results clarified that this method has high applicability. (C) 2005 Elsevier Inc. All rights reserved.ELSEVIER SCIENCE INC, Aug. 2005, EXPERIMENTAL THERMAL AND FLUID SCIENCE, 29(7) (7), 843 - 850, English[Refereed]Scientific journal
- Dec. 2004, Proceedings of the Japan-US Seminar on Two-Phase Flow Dynamics, Vol.1, No. 12, pp.89-84, EnglishBubbly flow measurement using multi-wave method[Refereed]International conference proceedings
- Sep. 2004, Proceedings of 4th International Symposium on ultrasonic Doppler method for fluid mechanics and fluid engineering, pp.111-114, EnglishApplication of Multi-wave TDX for multi-phase flow measurement[Refereed]International conference proceedings
- May 2004, Proceedings of 5th International Conference on Multiphase Flow, CD-ROM#407, EnglishBubbly flow measurement for each bubble size using ultrasonic Doppler method and wire mesh tomography[Refereed]International conference proceedings
- May 2004, Proceedings of 15th International Symposium on Transport Phenomena, pp.1-6, EnglishAdvanced measurement techniques for two-phase flow[Refereed]International conference proceedings
- Measurement of liquid turbulent structure in bubbly flow at low void fraction using ultrasonic Doppler methodMicroscopic structure in bubbly flows has been a topic of interest in the study of fluid dynamics. In the present paper, the ultrasonic Doppler method was applied to the measurement of bubbly. The experiments were carried out for an air-water dispersed bubbly flow in a 20 mm x 100 mm vertical rectangular channel having a void fraction smaller than 3%. Two ultrasonic transducers were installed on the outer surface of the test section with a contact angle of 45degrees off the vertical axis, one facing upward and the other facing downward. By applying statistical methods to the two directional velocity profiles, Reynolds stress profiles were calculated. Furthermore, to clarify the wake effect induced by the leading bubbles, the velocity profiles were divided into two types of data. The first one is for all of the liquid data and the other is the data which did not include the wake effect. For Re-m greater than or equal to 1,593, it was observed that the bubbles suppressed the liquid turbulence. Furthermore, comparing with the Reynolds stress profiles in bubbly flow, it was found that Reynolds stress profiles varied with the amount of bubbles present in the flow and the effect of wake causes turbulence in the liquid.ATOMIC ENERGY SOC JAPAN, Sep. 2003, JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 40(9) (9), 644 - 654, English[Refereed]Scientific journal
- Aug. 2003, Proceedings of 7 th Triennial International Symposium on Fluid Control, Measurement and Visualization, CD-ROM#214, EnglishThe novel velocity profile measuring method in bubbly flows using ultrasound pulses[Refereed]International conference proceedings
- Jun. 2003, Proceedings of 4th ASME/JSME Joint Fluids Engineering Conference, CD-ROM FEDSM2003-45384, EnglishMeasurement of bubbly flow in a vertical pipe using Ultrasonic Doppler Method[Refereed]International conference proceedings
- In this paper, combination measurement of ultrasonic Doppler method (UDM) and wire mesh tomography (WMT) techniques for two-phase bubbly flow measurement are proposed. The UDM can measure instantaneous velocity profiles along its measuring line. By applying statistical methods, the UDM can obtain liquid parameters in bubbly flow. The WMT is based on local conductivity measurement and can measure the two-dimensional void fraction distribution and bubble diameter. Using both techniques at the same conditions, the effects of the seeding particles in the liquid as reflector of ultrasonic are investigated. Furthermore, the void fraction is measured by taking the bubble diameter as the parameter. The measurement results clarified that bubble size plays very important roles for two-phase structures and the effectiveness of these techniques are shown.The Japan Society of Mechanical Engineers, 2003, The proceedings of the JSME annual meeting, 2003, 271 - 272, Japanese
- Sep. 2002, Proceedings of 3rd International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, pp.97-102, EnglishMeasurement of Reynolds Stress in Bubbly Flow using Ultrasonic Doppler Method[Refereed]International conference proceedings
- Microstructure of the flow field around a bubble in counter-current bubbly flowExperimental study was made on the flow structure around a bubble in air-water bubbly flow. In order to measure velocity profiles around a bubble, an Ultrasonic Velocity Profile monitor was employed, which can obtain an instantaneous velocity profile along its measuring line across a channel. The experiments were carried out in a 100 x 10 mm(2) rectangular channel for the air-water counter-current bubbly flow whose void fraction smaller than 7%. The bubble Reynolds number was ranged between 700 and 1000. Most bubbles had ellipsoidal shapes and rose up with wobbling motions. Our experimental results plotted in the form of non-dimensional velocity profiles show that the velocity field around a bubble has a structure similar to the turbulent boundary layer on a solid wall. On the other hand, an earlier analytical study by Moore [J. Fluid Mech. 16 (1963) 161] used an assumption of a spherical bubble rising in liquid irrotationally, and the solution was derived that the flow around a bubble being composed of a thin boundary layer and its outer main stream in potential flow. In this paper, the relation between these two types of boundary layer structures is discussed. (C) 2002 Elsevier Science Inc. All rights reserved.ELSEVIER SCIENCE INC, Jun. 2002, EXPERIMENTAL THERMAL AND FLUID SCIENCE, 26(2-4) (2-4), 221 - 227, English[Refereed]Scientific journal
- May 2001, Proceedings of 4th International Conference on Multiphase Flow, CD-ROM#788, EnglishLiquid Phase Flow Structure Around Bubble in Bubbly Co-current Flow[Refereed]International conference proceedings
- Sep. 2024, 混相流シンポジウム2024ガリウム合金中を上昇する気泡鎖の揺動に及ぼす水平磁場の影響Summary national conference
- May 2024, 第61回日本伝熱シンポジウム高温作動時の固体高分子形燃料電池内液水挙動の可視化評価Summary national conference
- Lead, Mar. 2024, 日本鉄鋼協会 第187回春季講演大会, #35, Japanese超音波トモグラフィ法による水平磁場印加時のガリウム合金中を上昇する気泡挙動の評価Summary national conference
- Corresponding, Oct. 2023, 日本機械学会熱工学コンファレンス 2023, #I115, Japanese磁性ナノ流体の沸騰に伴う伝熱面でのナノ粒子堆積に及ぼす磁場の影響Summary national conference
- Sep. 2023, 第27回動力・エネルギー技術シンポジウム, #B125, Japaneseクランプオン式超音波流量計の受信波形に基づく湿り蒸気流の流動様式評価と指示値補正法の検討Summary national conference
- Lead, Aug. 2023, 第51回可視化情報シンポジウム, #OS5-4, Japanese超音波トモグラフィによる気泡の三次元挙動の可視化Summary national conference
- Aug. 2023, 混相流シンポジウム2023, #OS1009, Japanese水平管群内沸騰熱伝達特性に及ぼす管ピッチの影響に関する研究Summary national conference
- Lead, Aug. 2023, 混相流シンポジウム2023, #OS1401, Japaneseガリウム合金中を上昇する気泡挙動に及ぼす水平磁場の影響Summary national conference
- Mar. 2023, 日本機械学会関西支部第98期定時総会講演会, #20402, Japanese固体粒子もしくは微細気泡が分散する液体の円管内熱流動特性に関する研究Summary national conference
- Lead, Mar. 2023, 混相流, 37(1) (1), 21 - 28高速超音波トモグラフィ法を用いた水平磁場印加時のガリウム合金中を上昇する連続気泡の流動評価[Invited]Introduction scientific journal
- Lead, Nov. 2022, 第100期流体工学部門講演会, # OS13-02, Japanese多目的超音波パルサレシーバを用いた流体計測と適用性評価Summary national conference
- Sep. 2022, 2022年度日本冷凍空調学会 年次大会, #D221, Japanese中性子ラジオグラフィによるミニチャネル直交型蒸発器内冷媒二相流の可視化とボイド率計測 不均一熱流束の影響Summary national conference
- Corresponding, Aug. 2022, 第50回 可視化情報シンポジウム, #090, Japaneseガリウム合金中を上昇する連続気泡の可視化Summary national conference
- Lead, Jul. 2022, 第26回動力・エネルギー技術シンポジウム, #B113, Japanese水平管内湿り蒸気流を対象としたクランプオン式超音波流量計の受信波形に基づく流動様式判別Summary national conference
- Jul. 2022, 第26回動力・エネルギー技術シンポジウム, #B231, Japaneseバイナリサイクル発電蒸発器の伝熱促進に関する研究Summary national conference
- May 2022, 第59回日本伝熱シンポジウム, #BPA-1439, Japanese中性子ラジオグラフィによる流れの可視化に基づく自励振動ヒートパイプの熱輸送特性評価Summary national conference
- Lead, May 2022, 計測技術, 50(6) (6), 10 - 15クランプオン式超音波流量計を用いた湿り蒸気流量の計測[Invited]Introduction commerce magazine
- Mar. 2022, 日本機械学会関西支部 第97期定時総会講演会, #30404, Japanese磁場印加時の磁性ナノ流体における沸騰伝熱特性に関する研究Summary national conference
- 2020, 日本機械学会流体工学部門講演会講演論文集(CD-ROM), 98thEffect of Bubble flow on Heat Transfer Characteristics in Gas-Liquid Two-Phase Flow in a Horizontal Tube Bundle
- 2020, 日本機械学会流体工学部門講演会講演論文集(CD-ROM), 98thStudy on Measurement Error for Wet Steam Flow Rate using Clamp-on Ultrasonic Flowmeter
- 2020, 日本機械学会流体工学部門講演会講演論文集(CD-ROM), 98thDevelopment of a Clamp-on Ultrasonic Flowmeter using Tomography Method
- 2020, 日本機械学会流体工学部門講演会講演論文集(CD-ROM), 98thVoid Fraction Measurement of Refrigerant Two-phase Flow in Cross-flow Mini-Channel Evaporator
- 2020, 日本機械学会流体工学部門講演会講演論文集(CD-ROM), 98thClarification of Water Transport and the Electrochemical Characteristics in Polymer Electrolyte Fuel Cell
- 2018, 日本伝熱シンポジウム講演論文集(CD-ROM), 55th固体高分子形燃料電池の膜厚方向水分布と電気特性の同時計測
- 日本冷凍空調学会, 2017, 日本冷凍空調学会年次大会講演論文集 Proceedings of the JSRAE Annual Conference, A324 - 1-5, JapanesePool Boiling Heat Transfer Characteristics around a Horizontal Low Thermal Conductivity Tube : Hysteresis effect and heat transfer enhancement by thermal spray coating under hot water heating condition
- 可視化情報学会, Jul. 2016, 可視化情報, 36(142) (142), 26 - 30, JapaneseVelocity Extension Method for Use with UVP and Application for Flow Rate Measurement[Invited]Introduction scientific journal
- The Japan Society of Mechanical Engineers, 11 Mar. 2016, 関西支部講演会講演論文集, 2016(91) (91), 405 - 405, JapaneseP031 Study on Water Spraying Characteristics from a Nozzle used in Condenser of Geothermal Power Plant
- The Japan Society of Mechanical Engineers, 11 Mar. 2016, 関西支部講演会講演論文集, 2016(91) (91), 344 - 344, JapaneseM810 Study of wall-shear stress during bubble passage in gas-liquid two-phase flow in a horizontal duct
- 日本冷凍空調学会, 2016, 日本冷凍空調学会年次大会講演論文集 Proceedings of the JSRAE Annual Conference, A113 - 1-5, Japanese正方形細管内一成分系垂直上昇気液二相流のボイド率特性
- 2016, KURRI-EKR (Web), (1) (1)X線ラジオグラフィによる水平バンドル内気液二相流のボイド率分布計測
- 2016, 混相流シンポジウム講演論文集(CD-ROM), 2016水平管群を横切る気液二相流の管群配列によるボイド率分布への影響
- 2016, 日本機械学会流体工学部門講演会講演論文集(CD-ROM), 94th水平バンドル内気液二相流の正方および千鳥配列の違いによる流動への影響
- 日本非破壊検査協会, Jan. 2016, 非破壊検査, 65(1) (1), 25 - 32, JapaneseVisualization of Mass Transfer Phenomena in Energy Equipment by using Neutron Radiography (Application to Polymer Electrolyte Fuel Cell and Refrigerating Equipment)[Invited]Introduction scientific journal
- 0405 Spectrum Analysis of Oscillatory Field in Chaotic Taylor-Couette Flow at Low Aspect RatioA Taylor-Couette Vortex Flow has a mild mixing effect even in high rotating speed with the inner cylinder. This effect is expected to be applied new bio-reactor system where the micro cells are damaged by strong share flows. Furthermore, in the case of small aspect ratio, this vortex has characteristics such as the different vortex structure, because of the Ekman effect in the top and bottom boundary layers and the acceleration of the inner cylinder. However, this vortex flow mechanism like a chaotic flow has not been investigated much. The purpose of this study is to understand the flow mechanism from a numerical analysis. In this report we mainly analyzed the process of transition to turbulent flow by direct numerical simulation.The Japan Society of Mechanical Engineers, 07 Nov. 2015, Fluids engineering conference ..., 2015, "0405 - 1"-"0405-4", Japanese
- 0402 Effect of velocity extension on the velocity accuracy using ultrasonic pulsed Doppler methodUltrasonic pulsed Doppler method (UDM) can obtain velocity profile along the ultrasonic beam path. However, the UDM has the limitation of the detectable velocity based on the measurement volume size. This problem was apparent when higher velocity were measured by using a velocity extension method. In order to investigate the accuracy of the velocity extension method, velocity distributions in a rotating cylinder were measured with changing of the measurement volume, and the relation between the maximum velocity required for the reflector to remain in the same measurement volume during the pulse interval, ν_The Japan Society of Mechanical Engineers, 07 Nov. 2015, Fluids engineering conference ..., 2015, "0402 - 1"-"0402-2", Japanese
, and the measured velocity was investigated. It was found that if measured velocities were higher than the ν_ , the velocity accuracy dramatically decreased. Further, the tendency was more apparent with going away from the transducer. - 1701 Evaluation of local void fraction in two-phase flow around tubes in horizontal bundleMeasurements of void fraction distribution around tubes across horizontal tube bundle in liquid-gas two-phase flow were carried out using X-ray radiography system. Under bubbly flow condition, it was observed that bubbles mainly passed through the vertical tube gaps and accumulated on the upstream side of the tubes. Also it was observed that void fraction was lower around the wall side tubes than that the center tubes. Measurements results of the void fraction were underestimated comparing to the previous studies. Because void fraction near the wall is lower than that in the center-region. Thus, cross-sectional averaged void fraction decreased comparing to the void fraction which was averaged except for the near-wall region.The Japan Society of Mechanical Engineers, 07 Nov. 2015, Fluids engineering conference ..., 2015, "1701 - 1"-"1701-2", Japanese
- H222 A study of heat transfer characteristics of oscillating heat pipeThis study experimentally investigated the heat transfer characteristics of oscillating heat pipe (OHP). The OHP was made of copper flat plate, and its flow pattern can be visualization. This OHP had 20 parallel channels. In this study the working fluid was ethanol. The installed condition of the experimental apparatus were performed at horizontal and vertical. As a result, the oscillation frequency of the liquid column increased with the heat input increase, and the effective thermal conductivity is increased. The liquid supply to the heating area a vertical condition was sufficient by gravity. Therefore the maximum effective thermal conductivity of the vertical condition and the horizontal condition was about 15 times and 12.5 times that of copper.The Japan Society of Mechanical Engineers, 23 Oct. 2015, Procee[d]ings of Thermal Engineering Conference, 2015, "H222 - 1"-"H222-2", Japanese
- J0420401 Measurement of condensation rate in subcooled flow boiling by multiwave ultrasoundThe condensation rate of vapour bubbles is an important parameter to determine the condensation heat/mass transfer in subcooled boiling. It is defined by v_c=dR/dt where R is the bubble radius and t is time. In the definition, bubbles are assumed to have a spherical shape. Accurate measurement of v_c is required to understand the flow physics. Together with that, the measured data is needed for numerical prediction of the flow behaviors. A novel method has been developed in this study to measure v_c by using multiwave ultrasound. In the method, the velocity of the top and bottom interfaces of condensing moving bubbles are measured by using two ultrasonic frequencies (namely multiwave ultrasound). Thus v_c can be calculated based on the velocity difference between the two measurement lines. The accuracy of the measured data of v_c has been well confirmed by comparison with the result of the optical visualization and analysis of the subcooled boiling in a vertical pipe (at atmospheric pressure). The data of ohen can be exploited for the analysis of the interfacial heat transfer coefficient in subcooled flow boiling. Such measurements and analyses can be applied to the high temperature/pressure flow conditions in industrial and engineering practice.The Japan Society of Mechanical Engineers, 13 Sep. 2015, Mechanical Engineering Congress, Japan, 2015, "J0420401 - 1"-"J0420401-5", Japanese
- F112 Development of multi-wave ultrasonic pulsed Doppler method for higher flow rate measurementAs ultrasonic pulsed Doppler has many advantages, it has been widely used for measuring velocity profiles. By integrating the obtained velocity profile all over the pipe, flow rate can be derived. The authors have developed feedback method which is a dealiasing method for high flow rate measurement and reported that measurement accuracy was improved by applying a multi-wave ultrasonic transducer. In this paper, effect of the size of measurement volume was investigated analytically and experimentally. In the analysis, measured velocities were considered to be ensemble average over the measurement volume. Analytical results showed the effect of channel-width was more significant than that of the sensor diameter. Furthermore, results of experiments were in good agreement with the analysis.The Japan Society of Mechanical Engineers, 07 Jun. 2015, National Symposium on Power and Energy Systems, 2015(20) (20), 141 - 142, Japanese
- 2015, 日本機械学会流体工学部門講演会講演論文集(CD-ROM), 93rd水平バンドル内気液二相流の管周り局所ボイド率評価
- GS05 UVP measurement for mixing in Taylor vortex reactor with a small aspect ratioTaylor vortex flow with a small aspect ratio has characteristics such as the different vortex structure, because of the Ekman effect in the top and bottom boundary layers and the acceleration of the inner cylinder. This feature is expected to develop a new typed mixing bioreactor system, but this vortex flow mechanism like a chaotic flow has not been investigated much. Furthermore, the multiphase flow such as the solid-liquid flow is important to be analyzed with a measurement system. An ultrasound measurement method is a useful device for observation of the flows. In this report we mainly analyzed the vortex structure in higher Reynolds number with using the ultrasound measurement system, and compare the result with Direct Numerical Simulation.The Japan Society of Mechanical Engineers, 25 Oct. 2014, Fluids engineering conference ..., 2014, "GS05 - 1"-"GS05-2", Japanese
- 0204 Measurement of void fraction distribution in the channel in two-phase flow across a horizontal tube bundleMeasurements of void-fraction distributions around a tube across horizontal tube bundle in liquid-gas two-phase flow were carried out using a void probe technique. Horizontal tube bundle was set in a vertical rectangular channel with 90 × 90 mm^2, and the tube layout was in-line. Outer diameter of the tube was 15 mm, and the pitch to the diameter ratio was 1.5. Void-fraction distributions were compared between 1^
, 4^ and 7^ rows in the 2^ column, and between 1^ and 2^ column in 4^ row. Furthermore, void-fraction distributions at 4^ row in the 2^ column were measured by the void-probes with different length. Void-fraction distributions at 4^ and 7^ rows were almost the same with each other, and it was confirmed that the inlet effect could be neglected at 4^ row. Void-fraction distributions at the 1^ column facing on the wall surface was different from at the 2^ column, and it were strongly influenced by the wall surface.The Japan Society of Mechanical Engineers, 25 Oct. 2014, Fluids engineering conference ..., 2014, "0204 - 1"-"0204-2", Japanese GS03 Development of high flow-rate measurement using ultrasonic velocity profile methodUltrasonic pulsed Doppler method (UDM) can obtain velocity profile on the ultrasonic beam path. By integrating the velocity profile over the pipe, flow-rate can be derived with high accuracy. In order to measure higher velocity by using feedback method, the larger measurement volume is required. With increasing of the measurement volume, it has been reported that the measurement accuracy near-wall region becomes low. In order to improve the measurement accuracy, multi-wave ultrasonic method which employs two ultrasonic sensors with basic frequency of 2 & 8 MHz is proposed. The velocity distribution was accurately obtained over the pipe by combining velocity distributions at 8 MHz for the near-wall region and 2 MHz for the region far from the transducer. Furthermore, the accuracy of the flow-rate was also improved with the proposed method.The Japan Society of Mechanical Engineers, 25 Oct. 2014, Fluids engineering conference ..., 2014, "GS03 - 1"-"GS03-2", JapaneseC211 Evaluation of Droplet Shape and Pressure Drop in the Gas Channel in a Polymer Electrolyte Fuel CellIn order to evaluate the local pressure drop in the gas channel of a polymer electrolyte fuel cell (PEFC), liquid droplet were modeled as two shapes by using neutron radiography. Based on the models, local pressure drop caused by a droplet were evaluated by CFD as a function of the water saturation, and it was applied to a network model calculating gas velocity distributions in the PEFC. Two dimensional water distributions measured by neutron radiography were applied to the network model, and the pressure drop between inlet and outlet of the gas channel were good agreement with the experimental results.The Japan Society of Mechanical Engineers, 25 Jun. 2014, National Symposium on Power and Energy Systems, 2014(19) (19), 277 - 278, Japanese日本工業出版㈱, May 2014, 超音波TECHNO, 26(3) (3), 90 - 94, Japanese超音波パルスドップラ法におけるパルスの繰り返し回数による速度分布計測への影響[Invited]Introduction commerce magazine可視化情報学会, 2014, 可視化情報学会誌 = ournal of the Visualization Society of Japan, 34(1) (1), 85 - 88, JapaneseEffect of Measurement Volume near Wall Region on the Velocity Accuracy in Ultrasonic Pulsed Doppler Method可視化情報学会, 2014, 可視化情報学会誌 = ournal of the Visualization Society of Japan, 34(1) (1), 81 - 84, JapaneseApplication of the Extension Method of the Velocity Limitation in the Ultrasonic Pulsed Doppler Method to High Flow-rate Measurement0206 Measurement of void fraction distribution around tube in two-phase flow across a horizontal tube bundleMeasurements of local void-fraction around tube in liquid-gas two-phase flow were carried out using a void probe technique. Horizontal tube bundle was set in a vertical rectangular channel with 90 X 90 mm^2, and the tube layout was in-line. Outer diameter of the tube was 15 mm, and the pitch to the diameter ratio was 1.5. Void fraction distributions were compared between 1^, 4^ and 7^ rows at the center column. Furthermore, the differences of the void fractions were compared around between the center and wall side. Void fraction distributions at inlet of the tube bundle strongly affected on the void fraction distributions in the bundle. Void fraction deviation increased with gas-flow rate. The flow regime changed from bubbly to churn-turbulent flow with increasing of the gas-flow rate, and it increased bubbles' horizontal movement in the bundle. Therefore, the void fraction at 0° and 180° increased with gas-flow rate. As a result, the void fraction distributions around a tube became flat in churn-turbulent flow regime.The Japan Society of Mechanical Engineers, 09 Nov. 2013, Fluids engineering conference ..., 2013, "0206 - 01"-"0206-02", Japanese 0209 Study of a Taylor Vortex Flow with a Small Aspect Ratio By using Ultrasound Velocity ProfilerTaylor vortex flow with a small aspect ratio has characteristics such as the different vortex structure, because of the Ekman effect in the top and bottom boundary layers and the acceleration of the inner cylinder. This feature is expected to develop a new typed mixing bioreactor system, but this vortex flow mechanism like a chaotic flow has not been investigated much. Furthermore, the multiphase flow such as the solid-liquid flow is important to be analyzed with a measurement system. A ultrasound measurement method is the one of useful device for observation of such kind flows. In this report we mainly analyzed the vortex structure in higher Reynolds number by using the ultrasound measurement system.The Japan Society of Mechanical Engineers, 09 Nov. 2013, Fluids engineering conference ..., 2013, "0209 - 01"-"0209-02", Japanese日本工業出版, Oct. 2013, 超音波TECHNO, 25(5) (5), 93 - 98, Japaneseフェイズドアレイ超音波流速分布計測法[Invited]Introduction commerce magazineJ041011 Measurements of bubbly counter-current two-phase flow in a vertical pipe using ultrasoundTwo ultrasound based methods for simultaneous characterizations of instantaneous velocity profiles of two-phase (liquid and gas) flow have been explored. Measurements of velocity profiles of both liquid phase and gas phase have been carried out for bubbly counter-current flow in a vertical pipe of 5cm pipe diameter (liquid flowing downwards and gas upwards). Two ultrasonic basic frequencies, 2MHz and 8MHz, are used independently and simultaneously along the sound path for measurement of bubble and liquid velocities respectively. The measurement methods are therefore referred to as the ultrasonic multiwave method. For signal processing, one method uses the ultrasonic Doppler method (UDM) and the other uses the ultrasonic time domain cross-correlation (UTDC) one. Based on the measured results, assessment of each method, when they are applied to this particular case of two-phase flow, is clarified.The Japan Society of Mechanical Engineers, 08 Sep. 2013, Mechanical Engineering Congress, Japan, 2013, "J041011 - 1"-"J041011-5", EnglishA102 Modeling of Liquid Drop in the Gas Channel and Analysis of Gas-velocity Distribution in a PEFCA network model has been proposed in order to predict the gas velocity distributions in a PEFC It analyzes the gas-velocity distributions depending on the local pressure drop which is affected by the gas-flow rate and the water accumulation Liquid drop form was observed in a PEFC by using neutron radiography, and classified into two models The one is small liquid drop accumulated near the rib corner, and the other is larger drop which is generated to be combined with small drops Numerical simulations were carried out for obtaining the local pressure drop caused by a liquid drop, and correlation equations were obtained for the pressure loss coefficientThe Japan Society of Mechanical Engineers, 19 Jun. 2013, National Symposium on Power and Energy Systems, 2013(18) (18), 5 - 6, Japanese0503 Measurement of wall-shear stress and liquid-film thickness during a bubble passage in a horizontal ductIn order to clarify the effect of bubble passage to wall-shear stress in air-liquid two-phase flow in a horizontal duct, instantaneous wall-shear stress and liquid-film thickness by using conductance probe were simultaneously measured. With increasing of gas flow-rate, time-series of liquid-film thickness and wall-shear stress changed around bubble's nose, and reduction ratio of the wall-shear stress slightly decreased. The time-average wall-shear stress was affected by the bubble's wake and liquid holdup which were obtained by pictures. Time-average wall-shear stress became lower than that of the single-phase flow when the liquid holdup around top-wall surface was lower than 60%.The Japan Society of Mechanical Engineers, 16 Nov. 2012, Fluids engineering conference ..., 2012, 211 - 212, JapaneseF051004 Measurement of Velocity Profile using UltrasonicAn ultrasonic velocity profile (UVP) method can measure instantaneous one-dimensional velocity profile along the measuring line. It is non-intrusive technique, and it can be easily applied for existing facilities from outside of the test section. Furthermore, the UVP can be used for measuring opaque fluids. The technique was originally developed for use in medical field. Takeda utilized the UVP for measuring in engineering fields in 1986, and it has been widely used for the measurement of the fluid. Now it has been used for many applications such as Taylor-couette flow, liquid metal, multi-phase flow, rheology measurement, flow-rate measurement, and so on.The Japan Society of Mechanical Engineers, 09 Sep. 2012, Mechanical Engineering Congress, Japan, 2012, "F051004 - 1"-"F051004-3", JapaneseD202 Measurements of Water Distributions in In-plane Direction of a PEFC by using Neutron Radiography and Analysis of Gas-velocity Distributions in the Channel and the GDLVisualization and measurement of water distributions in a polymer electrolyte fuel cell (PEFC) were carried out by means of neutron radiography for clarifying water effects on the performances. The two-dimensional water distributions were applied for a network model. It analyzes the gas-velocity distributions depending on the local pressure drop which is affected by the gas-flow rate and the water accumulation. Formation of the accumulated water in the channel was assumed based on measurement results of water distributions in through-plane direction. Furthermore, it was estimated that maximum water accumulation in the gas diffusion layer (GDL) and mechanism of water discharge from the GDL to the channel. From the analysis results, change of gas-velocity distributions depending on the water accumulation in the PEFC could be obtained.The Japan Society of Mechanical Engineers, 20 Jun. 2012, National Symposium on Power and Energy Systems, 2012(17) (17), 341 - 344, Japanese可視化情報学会, 2012, 可視化情報学会誌 = ournal of the Visualization Society of Japan, 32(1) (1), 245 - 248, JapaneseStudy on Signal Processing of Ultrasonic Doppler Method using Wavelet AnalysisG207 Measurement of water distribution by using neutron radiography and network analysis of gas-velocity distributions in a PEFCFuel gas (hydrogen gas) and oxidant gas (air) are supplied to a Polymer Electrolyte Fuel Cell (PEFC). Condensation may occur in the cathode side, since air is super-saturated by the fuel cell reactions. If condensed water exists in a gas diffusion layer (GDL) or the gas channels, it may affect the fuel cell performances because of blocking the oxygen from reaching the cathode reaction site. In order to clarify water effects on performances of a PEFC, visualization and quantitative measurements of water distributions in a PEFC were carried out by means of neutron radiography. A network analysis of gas-velocity distribution was applied for the experimental results. It analyzes the gas-velocity distribution depending on the flow resistance which is the pressure drop. Applying the measured data of water thickness, pressure drop in the gas channel and the GDL can be obtained.The Japan Society of Mechanical Engineers, 22 Jun. 2011, National Symposium on Power and Energy Systems, 2011(16) (16), 457 - 460, JapaneseG206 Three-Dimensional Visualization and Measurement of Water Distributions in PEFC by Dynamic CT Method on Neutron RadiographyVisualization of dynamic three-dimensional water behavior in a PEFC stack was carried out by neutron CT for clarifying water effects on performances of a Polymer Electrolyte Fuel Cell (PEFC) stack. Neutron radiography system at JRR-3 in Japan Atomic Energy Agency was used. An operating stack with three cells based on Japan Automobile Research Institute standard was visualized. A consecutive CT reconstruction method by rotating the fuel stack continuously was developed by using a neutron image intensifier and a C-MOS high speed video camera. The dynamic water behavior in channels in the operating PEFC stack was clearly visualized 15 sec in interval by the developed dynamic neutron CT system. From the CT reconstructed images, evaluation of water amount in each cell was carried out. It was shown that the water distribution in each cell was correlated well with power generation characteristics in each cell.The Japan Society of Mechanical Engineers, 22 Jun. 2011, National Symposium on Power and Energy Systems, 2011(16) (16), 453 - 456, JapaneseThe Basic Study of Phased Ultrasonic Array VelocimetryUVP (Ultrasound Velocity Profile monitor) employing pulsed ultrasound has been widely used for measuring velocity profiles. However, the UVP can obtain only one-dimensional velocity profiles. To obtain two-dimensional velocity profiles, a measuring system using phased array technique was developed. In this study, a suitable transducer was designed, and evaluated its performance from intensities of sound fields. A signal processing system for measuring the velocity profiles was developed, and applied for a Taylor-Couette flow. As a result, a two dimensional velocity profile was obtained, and the vortices could be confirmed.The Institute of Electronics, Information and Communication Engineers, 21 Apr. 2011, IEICE technical report, 111(21) (21), 29 - 34, JapaneseThe Japan Society of Mechanical Engineers, 19 Mar. 2011, 関西支部講演会講演論文集, 2011(86) (86), "13 - 34", Japanese1328 Study on Freezing Phenomenna of Water in a Porous Layer Used as Gas Diifusion Layer in PEFC15 Mar. 2011, 混相流 = Japanese journal of multiphase flow, 25(1) (1), 3 - 3, JapaneseResources and Multiphase Flow : For efficient use of limited resources of our earthD202 Visualization of Water Distribution in PEFC by using Neutron Dynamic CTFuel gas (hydrogen gas) and oxidant gas (air) are supplied to a Polymer Electrolyte Fuel Cell (PEFC) in saturated moist condition to keep a membrane wet. Condensation may occur in the cathode side, since the air is super-saturated by the fuel cell reaction. If the condensed water stay in an electrode, Gas Diffusion Layer (GDL) or gas channels, it may affect on the fuel cell performance. In this study, dynamic CT technology which performed 1 CT per 1 sec was developed, and visualization of three-dimensional water distributions in an operating PEFC was measured by using neutron dynamic CT. As a result, it was confirmed that the developed system can measure three-dimensional water distribution in the PEFC and, condensed water had a significant influence on the fuel cell performances.The Japan Society of Mechanical Engineers, 20 Jun. 2010, National Symposium on Power and Energy Systems, 2010(15) (15), 381 - 384, Japanese日本非破壊検査協会, 01 Mar. 2010, 非破壊検査 : journal of N.D.I, 59(3) (3), 106 - 109, JapaneseDevelopment of Neutron Dynamic CT System日本混相流学会, 15 Dec. 2009, Japanese journal of multiphase flow, 23(4) (4), 447 - 450, JapaneseMultiphase Thermo-Fluid Dynamics of Dept. of Mechanical Eng. in Kobe UniversityD141 Measurement of Distribution of Water of Thickness Direction in PEFC by Neutron RadiographyThis paper presents a new measurement technique of neutron radiography for fuel cell researches. Water condenses in MEA, GDL and channel in cathode side of PEFC (Polymer Electrolyte Fuel Cell) while PEFC generates electricity. It is expected the condensed water may decrease power generation capability. Visualization of the condensed water behavior is important to study the fuel cell and neutron radiography is effective for the visualization. A borescope system was introduced into neutron radiography to visualize water of thickness in the MEA and the GDL. Borescope system enables neutron radiography to take a picture pixel size of which is 6.5μm and to measure water of thickness in the MEA and the GDL with the exposure time of 50 seconds.The Japan Society of Mechanical Engineers, 06 Nov. 2009, Procee[d]ings of Thermal Engineering Conference, 2009, 111 - 112, JapaneseThe Japan Society of Mechanical Engineers, 16 Mar. 2009, 関西支部講演会講演論文集, 2009(84) (84), "11 - 24", Japanese1124 A study of thermal hydraulics in the target for acceleratorOS9-5 Trial Measurement on Two-phase Flow using a Multi-wave Ultrasonic Velocity Profile Method : 3rd Report: Measurement of Slug Flow and Visualization using High-speed CameraA new measurement technique referred to as multi-wave ultrasonic method was applied to measuring slug flow. The technique was developed for measuring two-phase flow using two different ultrasonic frequencies. The technique employs a multi-wave ultrasonic transducer (TDX) which includes two different ultrasonic elements. With emitting two kinds of ultrasonic at the same time, two kinds of ultrasonic echo signals can be obtained. The echo intensity reflected from liquid-gas interface is higher than that from micro particles seeded in water. Comparing with the each signal, echo signals from liquid-gas interface and micro-particles can be divided. Applying an ultrasonic time-domain cross-correlation method for the signals, velocity distributions of the both phases can be obtained at the same time and the position. Comparing the velocity data with the obtained images by using high-speed camera, it was confirmed that the multi-wave method can measure the both liquid and gas velocity distributions at the slug flow.The Japan Society of Mechanical Engineers, 13 Jun. 2007, National Symposium on Power and Energy Systems, 2007(12) (12), 109 - 110, JapaneseThe Japan Society of Mechanical Engineers, 28 Oct. 2005, Fluids engineering conference ..., 2005, 164 - 164, Japanese1108 Development of a measurement technique for multi-phase flow using a multi-wave ultrasonic methodOS9-09 Trial Measurement on Two-phase Flow using a Multi-wave Ultrasonic Velocity Profile Method : 2nd Report: Ultrasound Time Domain Correlation method for Bubble Rising VelocityThis paper proposes a new measurement technique for multi-phase flow. To measure two kinds of phases at the same place and the time. Multi-wave TDX was newly developed. This TDX includes the two different ultrasonic elements. Applying the effects of measuring volume, the liquid velocity and me bubbles' rising velocity are obtained using the UDM in two-phase bubbly flow. Furthermore, applying ultrasound correlation method (UTDC) for the Multi-wave TDX, the bubbles' rising velocity can be obtained at more accurately. With emitting two kinds of ultrasonic at the same time, two different signals can be obtained. Comparing with the each signal, the bubbles' velocity information can be eliminated from the other signal. Using the UTDC and the signal comparison method, the velocity distribution can be obtained at the same time and the position. This method does not need the velocity difference between two objects, such as the bubbles and the liquid. Hence, this method can be applied for other multi-phase flow.The Japan Society of Mechanical Engineers, 28 Jun. 2005, National Symposium on Power and Energy Systems, 2005(10) (10), 255 - 256, JapaneseTrial measurement on two-phase now using a multi-wave ultrasonic velocity profile methodA new technique for multi-phase flow measurement based on the ultrasonic Doppler method(UVP method) is proposed. Using different sizes(frequency) of ultrasonic sensor for the UVP measurement, the measured, data apparently differ. With a change in the measurement volume, the velocity PDF significantly changes. Applying this method for multi-phase flow, several kinds of particles which sizes are greatly different can be measured for each velocity distributions. To measure each velocity at the same time and position, the Multi-wave TDX is newly developed. Using the Multi-wave TDX, this method is utilized for the measurement of bubbly flow in vertical pipe. To confirm the accuracy of each velocity measurement, the velocity PDFs are calculated. The results clarified that this method has high applicability.The Japan Society of Mechanical Engineers, 22 Jun. 2004, National Symposium on Power and Energy Systems, 2004(9) (9), 101 - 102, Japanese2001, 日本混相流学会年会講演会2001超音波流速分布計測計を用いた気液二相流計測における測定体積の影響
■ Books And Other Publications- Contributor, 3.5超音波流速計，6.2.1 流量，6.2.2体積率，6.3.1体積率, 日本機械学会, Apr. 2022, Japanese, ISBN: 9784888983266流体計測法
- Joint work, S&T出版, Aug. 2015, Japanese, ISBN: 9784907002473PEFCの内部現象・反応機構と評価・解析技術，（分担執筆：第5章 第2節「中性子ラジオグラフィによる発電時のPEFC内水輸送現象の可視化と計測」Scholarly book
- Joint work, コロナ社, May 2013, Japanese, ISBN: 9784339046236エネルギー変換論入門Textbook
- Joint work, Springer, Sep. 2012, English, ISBN: 9784431540250Ultrasonic Doppler velocity profiler for fluid flowScholarly book
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- 日本機械学会関西支部 関西学生会2021年度学生員卒業研究発表講演会, Mar. 2022水平管群沸騰熱伝達における核沸騰伝熱促進効果への管ピッチの影響に関する研究
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- 日本機械学会関西支部 関西学生会2021年度学生員卒業研究発表講演会, Mar. 2022トモグラフィ法を用いたクランプオン式超音波流量計に関する研究
- 日本機械学会関西支部 関西学生会2021年度学生員卒業研究発表講演会, Mar. 2022中性子ラジオグラフィによるミニチャネル直交型蒸発器内冷媒二相流の可視化とボイド率計測（不均一熱流束の影響）
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- 日本機械学会 第99期流体工学部門講演会, Nov. 2021トモグラフィー法を用いたクランプオン型超音波流量計の開発Oral presentation
- 日本混相流学会 混相流シンポジウム2021, Aug. 2021超音波トモグラフィを用いたガリウム合金中を上昇する連続気泡の流動評価Oral presentation
- 第25回動力・エネルギー技術シンポジウム, Jul. 2021ミニチャネル直交型蒸発器における冷媒相分布に関する研究 （ボイド率計測結果に基づく偏流評価）
- 日本機械学会 第98期流体工学部門講演会, Nov. 2020高速超音波トモグラフィ手法を用いた気泡流の三次元ボイド分布計測
- 日本機械学会 第98期流体工学部門講演会, Nov. 2020トモグラフィ法を用いたクランプオン式超音波流量計の開発
- 日本機械学会 第98期流体工学部門講演会, Nov. 2020クランプオン式超音波流量計による湿り蒸気流量計測における計測誤差の検討
- 日本機械学会 第98期流体工学部門講演会, Nov. 2020ミニチャネル直交型蒸発器内冷媒二相流のボイド率分布計測
- 日本機械学会 第98期流体工学部門講演会, Nov. 2020水平管群内気液二相流の熱伝達特性に及ぼす気泡流動の影響
- 日本機械学会 第98期流体工学部門講演会, Oct. 2020固体高分子形燃料電池内の水分布の可視化と電気化学特性に関する研究
- 第48回可視化情報シンポジウム, Sep. 2020超音波トモグラフィによる液体金属中の気泡流動の可視化
- 2020年度日本冷凍空調学会年次大会, Sep. 2020半円断面ミニチャネル内の熱流動特性に関する研究
- 日本機械学会関西学生会 2019年度学生員卒業研究発表講演会, Mar. 2020ミニチャネル直交型蒸発器内冷媒二相流の流動特性に関する研究Oral presentation
- 日本機械学会関西学生会 2019年度学生員卒業研究発表講演会, Mar. 2020超音波による気泡流動の評価手法に関する研究Oral presentation
- 日本機械学会関 西学生会 2019年度学生員卒業研究発表講演会, Mar. 2020固体高分子形燃料電池内の水分布と電気特性に関する研究Oral presentation
- 日本機械学会関西学生会 2019年度学生員卒業研究発表講演会, Mar. 2020溶射伝熱管によるプール沸騰伝熱促進に関する研究Oral presentation
- 日本機械学会関西学生会 2019年度学生員卒業研究発表講演会, Mar. 2020沸騰伝熱促進管を挿入した水平管群の沸騰伝熱特性に関する研究Oral presentation
- 日本機械学会関 西学生会 2019年度学生員卒業研究発表講演会, Mar. 2020自励振動ヒートパイプの始動特性に関する研究Oral presentation
- 日本機械学会関 西学生会 2019年度学生員卒業研究発表講演会, Mar. 2020ナノ流体の沸騰伝熱促進に関する研究Oral presentation
- 11th International Symposium on Measurement Techniques for Multiphase Flows, Nov. 2019Development of an ultrasonic tomography for measuring void distribution in liquid-metal bubble columnOral presentation
- 日本機械学会第97 期流体工学部門講演会, Nov. 2019クランプオン式超音波流量計による蒸気流量計側のための超音波透過波形の評価Poster presentation
- 2019年度日本冷凍空調学会年次大会, Sep. 2019ミニチャネル直交型蒸発器内の冷媒流れの可視化とボイド率計測，穴あきもしくはオフセットリブによる流動分配改善効果Oral presentation
- 2019年度日本冷凍空調学会年次大会, Sep. 2019水平管群沸騰熱伝達に及ぼす管配列の影響に関する研究Oral presentation
- 日本混相流学会 混相流シンポジウム2019, Aug. 2019, JapaneseDevelopment of Ultrasonic Tomography for Measuring Instantaneous Void Distribution in Bubbly FlowOral presentation
- 第47回可視化情報シンポジウム, Jul. 2019超音波トモグラフィによる気泡流のボイド分布計測法の開発
- 第24回動力・エネルギー技術シンポジウム, Jun. 2019水平管群内空気－水二相流の熱流動特性に及ぼすピッチ直径比の影響に関する研究Oral presentation
- 日本機械学会動力・エネルギー技術シンポジウム講演論文集(CD-ROM), Jun. 2019, JapaneseEvaluation Method of Transmitted Signal for Clamp‐on Ultrasonic Flowmeter in Measuring Wet Steam FlowOral presentation
- 日本機械学会 関西支部第94期定時総会講演会, Mar. 2019, Japanese, 日本機械学会 関西支部, 草津, Domestic conference並列垂直管内沸騰二相流の流動特性に関する研究Oral presentation
- 日本機械学会 関西学生会平成30年度学生員卒業研究発表講演会, Mar. 2019, Japanese, 日本機械学会 関西学生会, 草津, Domestic conference反射法を用いた超音波トモグラフィによる気泡流のボイド分布計測Oral presentation
- 日本機械学会 関西学生会平成30年度学生員卒業研究発表講演会, Mar. 2019, Japanese, 日本機械学会 関西学生会, 草津, Domestic conference水平管群周り空気 －水気液二相流の熱流動特性に及ぼすピッチ直径比の影響に関する研究Oral presentation
- 日本機械学会 関西学生会平成30年度学生員卒業研究発表講演会, Mar. 2019, Japanese, 日本機械学会 関西学生会, 草津, Domestic conference水平管群の沸騰伝熱特性に関する研究Oral presentation
- 日本機械学会 関西学生会平成30年度学生員卒業研究発表講演会, Mar. 2019, Japanese, 日本機械学会 関西学生会, 草津, Domestic conferenceクランプオン式超音波流量計による蒸気流量計測の検討Oral presentation
- 日本機械学会 関西学生会平成30年度学生員卒業研究発表講演会, Mar. 2019, Japanese, 日本機械学会 関西学生会, 草津, Domestic conferencePEFC内部の水輸送現象が発電性能に与える影響の解明Oral presentation
- 第96期流体工学部門講演会, Nov. 2018, Japanese, 日本機械学会流体工学部門, 室蘭, Domestic conference反射法を用いた超音波トモグラフィによる気液二相流のボイド分布計測法の開発Poster presentation
- 第96期流体工学部門講演会, Nov. 2018, Japanese, 日本機械学会流体工学部門, 室蘭, Domestic conferenceクランプオン式超音波流量計による蒸気流量計測の検討Poster presentation
- 2018年度日本冷凍空調学会年次大会, Sep. 2018, Japanese, 日本冷凍空調学会, 郡山, Domestic conference水平狭隘流路内サブクール沸騰熱伝達における溶射被膜の効果に関す研究Oral presentation
- 2018年度日本冷凍空調学会年次大会, Sep. 2018, Japanese, 日本冷凍空調学会, 郡山, Domestic conference水平管群内沸騰熱伝達に関する研究Oral presentation
- 2018年度日本冷凍空調学会年次大会, Sep. 2018, Japanese, 日本冷凍空調学会, 郡山, Domestic conferenceミニチャンネル直交型蒸発器内の冷媒流れの可視化とボイド率計測Oral presentation
- 11th World Conference on Neutron Radiography, Sep. 2018, English, International Society for Neutron Radiography, Sydney, Australia, International conferenceVisualization and measurement of boiling flow behaviors in parallel mini-channel heat exchanger by neutron radiographyPoster presentation
- 11th World Conference on Neutron Radiography, Sep. 2018, English, International Society for Neutron Radiography, Sydney, Australia, International conferenceSimultaneous measurements of water distribution and electrochemical characteristics in polymer electrolyte fuel cellPoster presentation
- 混相流シンポジウム2018, Aug. 2018, Japanese, 日本混相流学会, 仙台, Domestic conference自励振動型ヒートパイプの設置姿勢による熱輸送特性への影響Oral presentation
- 混相流シンポジウム2018, Aug. 2018, Japanese, 日本混相流学会, 仙台, Domestic conference広角超音波センサを用いた気液二相流のボイド分布計測法の検討Oral presentation
- 第23回動力・エネルギー技術シンポジウム, Jun. 2018, Japanese, 日本機械学会動力・エネルギー部門, 宇部, Domestic conference水平管群の沸騰熱流動に関する研究Oral presentation
- 第23回動力・エネルギー技術シンポジウム, Jun. 2018, Japanese, 日本機械学会動力・エネルギー部門, 宇部, Domestic conferenceクランプオン式超音波流量計による湿り蒸気流量計測の検討Oral presentation
- 第23回動力・エネルギー技術シンポジウム, Jun. 2018, Japanese, 日本機械学会動力・エネルギー部門, 宇部, Domestic conferenceT 字合流部に生じる熱疲労発生メカニズムの検討Oral presentation
- 第55回日本伝熱シンポジウム, May 2018, Japanese, 日本伝熱学会, 札幌, Domestic conference固体高分子形燃料電池内の膜厚方向水分布と電気特性の同時計測Oral presentation
- 関西学生会2017年度学生員卒業研究発表講演会, Mar. 2018, Japanese, 日本機械学会関西支部, 寝屋川, Domestic conference低沸点冷媒の膜沸騰遷移条件に関する研究Oral presentation
- 関西学生会2017年度学生員卒業研究発表講演会, Mar. 2018, Japanese, 日本機械学会関西支部, 寝屋川, Domestic conference水平管群を横切る気液二相流の管周りボイド率と伝熱特性に関する研究Oral presentation
- 関西学生会2017年度学生員卒業研究発表講演会, Mar. 2018, Japanese, 日本機械学会関西支部, 寝屋川, Domestic conference水平管群の沸騰熱流動に関する研究Oral presentation
- 関西学生会2017年度学生員卒業研究発表講演会, Mar. 2018, Japanese, 日本機械学会関西支部, 寝屋川, Domestic conference自励振動ヒートパイプの設置姿勢による熱輸送特性への影響に関する研究Oral presentation
- 関西学生会2017年度学生員卒業研究発表講演会, Mar. 2018, Japanese, 日本機械学会関西支部, 寝屋川, Domestic conference固体高分子形燃料電池発電時の水分量と電気特性の評価Oral presentation
- 関西学生会2017年度学生員卒業研究発表講演会, Mar. 2018, Japanese, 日本機械学会関西支部, 寝屋川, Domestic conferenceミニチャネル直交型蒸発器内の冷媒流れの可視化Oral presentation
- 関西学生会2017年度学生員卒業研究発表講演会, Mar. 2018, Japanese, 日本機械学会関西支部, 寝屋川, Domestic conferenceクランプオン式超音波流量計による蒸気流量計測に関する研究Oral presentation
- 関西学生会2017年度学生員卒業研究発表講演会, Mar. 2018, Japanese, 日本機械学会関西支部, 寝屋川, Domestic conferenceT字配管合流部における噴流の揺動現象に関する研究Oral presentation
- 可視化情報全国講演会 (室蘭2017), Nov. 2017, Japanese, 可視化情報学会, 室蘭, Domestic conference有限長固定端を持つTaylor-Couette流れの壁面近傍における低周波数ブロードバンド成分の影響Oral presentation
- 可視化情報全国講演会 (室蘭2017), Nov. 2017, Japanese, 可視化情報学会, 室蘭, Domestic conference超音波を用いた気液二相流におけるボイド率分布計測法の検討Oral presentation
- 可視化情報全国講演会 (室蘭2017), Nov. 2017, Japanese, 可視化情報学会, 室蘭, Domestic conference超音波を用いたT字合流部における噴流の可視化Oral presentation
- 平成29年度非破壊検査・可視化・分析技術研究会, Nov. 2017, Japanese, 中性子産業利用推進協議会, 東京, Domestic conference中性子ラジオグラフィによるエネルギー機器の診断[Invited]Invited oral presentation
- 2017年度 日本冷凍空調学会 年次大会, Sep. 2017, Japanese, 日本冷凍空調学会, 町田, Domestic conference低熱伝導水平円管周りのプール沸騰熱伝達特性－温水加熱での加熱履歴の影響と溶射被膜による伝熱促進－Oral presentation
- 混相流シンポジウム2017, Aug. 2017, Japanese, 日本混相流学会, 調布, Domestic conference超音波による液体金属気液二相流の気液速度分布計測手法の開発Oral presentation
- 混相流シンポジウム2017, Aug. 2017, Japanese, 日本混相流学会, 調布, Domestic conference自励振動型ヒートパイプの熱輸送特性に及ぼす流路形状の影響Oral presentation
- 第45回可視化情報シンポジウム, Jul. 2017, Japanese, 可視化情報学会, 東京, Domestic conference速度拡張法を用いた超音波パルスドップラ法の不確かさ低減手法の検討Oral presentation
- 第22回動力・エネルギー技術シンポジウム, Jun. 2017, Japanese, 日本機械学会, 豊橋, Domestic conferenceプラント配管のT字合流部の流動特性に関する研究Oral presentation
- 第22回動力・エネルギー技術シンポジウム, Jun. 2017, Japanese, 日本機械学会, 豊橋, Domestic conferenceガス拡散層の相対透過率による固体高分子形燃料電池内水輸送への影響Oral presentation
- 日本機械学会関西学生会平成28年度学生員卒業研究発表講演会, Mar. 2017, Japanese, 日本機械学会関西支部, 吹田, Domestic conference溶射皮膜を有する水平円管における等温壁加熱でのプール沸騰熱伝達特性に関する研究Oral presentation
- 日本機械学会関西学生会平成28年度学生員卒業研究発表講演会, Mar. 2017, Japanese, 日本機械学会関西支部, 吹田, Domestic conference超音波によるボイド率分布計測法の検討Oral presentation
- 日本機械学会関西学生会平成28年度学生員卒業研究発表講演会, Mar. 2017, Japanese, 日本機械学会関西支部, 吹田, Domestic conference水平および垂直管内一成分系二相流の流動挙動に関する研究Oral presentation
- 日本機械学会関西学生会平成28年度学生員卒業研究発表講演会, Mar. 2017, Japanese, 日本機械学会関西支部, 吹田, Domestic conference高温伝熱管のサブクール水によるリウェット現象に関する研究Oral presentation
- 日本機械学会関西支部第92期定時総会講演会, Mar. 2017, Japanese, 日本機械学会関西支部, 吹田, Domestic conference高温金属管での急冷過程におけるリウェット速度に関する研究Oral presentation
- 日本機械学会関西学生会平成28年度学生員卒業研究発表講演会, Mar. 2017, Japanese, 日本機械学会関西支部, 吹田, Domestic conference固体高分子形燃料電池の流路液滴による膜厚方向物質輸送への影響Oral presentation
- 日本機械学会関西学生会平成28年度学生員卒業研究発表講演会, Mar. 2017, Japanese, 日本機械学会関西支部, 吹田, Domestic conference一成分系垂直上昇気液二相流のボイド率特性に及ぼす流路断面形状の影響に関する研究Oral presentation
- 第94期日本機械学会流体工学部門講演会, Nov. 2016, Japanese, 日本機械学会, 宇部, Domestic conference水平バンドル内気液二相流の正方および千鳥配列違いによる流動への影響Oral presentation
- 2016年度日本冷凍空調学会年次大会, Sep. 2016, Japanese, 日本冷凍空調学会, 神戸, Domestic conference正方形細管内一成分系垂直上昇気液二相流のボイド率特性Oral presentation
- 2016年度日本冷凍空調学会年次大会, Sep. 2016, Japanese, 日本冷凍空調学会, 神戸, Domestic conference水平管群内気液二相流管周りの熱流動特性に関する研究Oral presentation
- 日本混相流学会混相流シンポジウム2016, Aug. 2016, Japanese, 日本混相流学会, 京都, Domestic conference水平管群を横切る気液二相流の管群配列によるボイド率分布への影響Oral presentation
- 日本混相流学会混相流シンポジウム2016, Aug. 2016, Japanese, 日本混相流学会, 京都, Domestic conference自励振動型ヒートパイプの内部流動と熱輸送特性に関する研究Oral presentation
- 第44回可視化情報シンポジウム, Jul. 2016, Japanese, 可視化情報学会, 東京, Domestic conference低アスペクト比Taylor-Couette流れの固定端近傍におけるカオス流動の周波数解析Oral presentation
- 第44回可視化情報シンポジウム, Jul. 2016, Japanese, 可視化情報学会, 東京, Domestic conference超音波パルスドップラ法における速度限界拡張手法の信頼性評価Oral presentation
- 第44回可視化情報シンポジウム, Jul. 2016, Japanese, 可視化情報学会, 東京, Domestic conference超音波パルスドップラ法におけるパルス繰り返し数によるドップラ信号強度への影響Oral presentation
- 第21回動力・エネルギー技術シンポジウム, Jun. 2016, Japanese, 日本機械学会, 横浜, Domestic conference伝播時間差式超音波流量計の精度に及ぼす速度分布の影響Oral presentation
- 第53回日本伝熱シンポジウム, Jun. 2016, Japanese, 日本伝熱学会, 大阪, Domestic conference自励振動型ヒートパイプの流路形状による熱輸送特性への影響Oral presentation
- 第53回日本伝熱シンポジウム, Jun. 2016, Japanese, 日本伝熱学会, 大阪, Domestic conference固体高分子形燃料電池における膜厚方向の水分布に関する研究Oral presentation
- 日本機械学会関西支部 第91期定時総会講演会, Mar. 2016, Japanese, 日本機械学会関西支部, 大阪, Domestic conference地熱発電所用復水器における水噴霧特性に関する研究Poster presentation
- 日本機械学会関西学生会平成27年度学生員卒業研究発表講演会, Mar. 2016, Japanese, 日本機械学会関西支部, 大阪, Domestic conference水平管群を横切る気液二相流に関する研究Oral presentation
- 日本機械学会関西支部 第91期定時総会講演会, Mar. 2016, Japanese, 日本機械学会関西支部, 大阪, Domestic conference水平ダクト内気液二相流における気泡通過時の壁面せん断応力変化に関する研究Oral presentation
- 日本機械学会関西学生会平成27年度学生員卒業研究発表講演会, Mar. 2016, Japanese, 日本機械学会関西支部, 大阪, Domestic conference固体高分子形燃料電池内の水輸送現象に関する研究Oral presentation
- 第93期日本機械学会流体工学部門講演会, Nov. 2015, Japanese, 日本機械学会, 東京, Domestic conference低アスペクト比Taylor渦流れのカオス流動における振動場の解析Oral presentation
- 第93期日本機械学会流体工学部門講演会, Nov. 2015, Japanese, 日本機械学会, 東京, Domestic conference超音波パルスドップラ法の計測速度限界拡張による測定精度への影響評価Oral presentation
- 第93期日本機械学会流体工学部門講演会, Nov. 2015, Japanese, 日本機械学会, 東京, Domestic conference水平バンドル内気液二相流の管周り局所ボイド率評価Oral presentation
- 熱工学コンファレンス2015, Oct. 2015, Japanese, 日本機械学会, 大阪, Domestic conference自励振動型ヒートパイプの熱輸送特性に関する研究Oral presentation
- 7th European-Japanese Two-Phase Flow Group Meeting, Oct. 2015, English, Zermatt, Switzerland, International conferenceStudy on Water Transport Phenomena in Polymer Electrolyte Membrane Fuel Cell in the Through-Plane DirectionOral presentation
- 日本機械学会2015年度年次大会, Sep. 2015, Japanese, 日本機械学会, 札幌, Domestic conference多波長超音波によるサブクール沸騰中の凝縮速度計測Oral presentation
- 第52回日本伝熱シンポジウム, Jun. 2015, Japanese, 日本伝熱学会, 福岡, Domestic conference固体高分子形燃料電池における膜厚方向の水輸送現象Oral presentation
- 第20回動力・エネルギー技術シンポジウム, Jun. 2015, Japanese, 日本機械学会, 仙台, Domestic conferenceマルチウェイブ超音波パルスドップラ法による高流量計測手法の開発Oral presentation
- 日本機械学会関西学生会学生員卒業研究発表講演会, Mar. 2015, Japanese, 日本機械学会関西支部, 京都, Domestic conference超音波パルスドップラ法における計測速度限界の拡張に関する研究Oral presentation
- 日本機械学会関西学生会学生員卒業研究発表講演会, Mar. 2015, Japanese, 日本機械学会関西支部, 京都, Domestic conference水平管群を横切る気液二相流のボイド率分布計測Oral presentation
- 日本機械学会関西学生会学生員卒業研究発表講演会, Mar. 2015, Japanese, 日本機械学会関西支部, 京都, Domestic conference自励振動ヒートパイプの流動特性に関する研究Oral presentation
- 日本機械学会関西学生会学生員卒業研究発表講演会, Mar. 2015, Japanese, 日本機械学会関西支部, 京都, Domestic conference固体高分子型燃料電池内における水輸送に関する研究Oral presentation
- 第55回電池討論会, Nov. 2014, Japanese, 京都, Domestic conference中性子ラジオグラフィを用いたMPLによるPEFC内水輸送現象への影響評価Oral presentation
- 第92期日本機械学会流体工学部門講演会, Oct. 2014, Japanese, 日本機械学会, 富山, Domestic conference低アスペクト比Taylor渦による撹拌混合のための超音波流速分布計測法についてOral presentation
- 第92期日本機械学会流体工学部門講演会, Oct. 2014, Japanese, 日本機械学会, 富山, Domestic conference超音波流速分布計測法を用いた高流量計測手法の開発Oral presentation
- 第92期日本機械学会流体工学部門講演会, Oct. 2014, Japanese, 日本機械学会, 富山, Domestic conference水平管群を横切る気液二相流の流路内ボイド率分布計測Oral presentation
- 10th World Conference on Neutron Radiography, Oct. 2014, English, Grindelwald, Switzerland, International conferenceVisualization of Water Accumulation Process in Polymer Electrolyte Fuel Cell using Neutron RadiographyPoster presentation
- 混相流シンポジウム2014, Jul. 2014, Japanese, 日本混相流学会, 札幌, Domestic conference沸騰気泡流に対する多波長UVPを用いた計測Oral presentation
- 第42回可視化情報シンポジウム, Jul. 2014, Japanese, 可視化情報学会, 東京, Domestic conference超音波速度計測によるアスペクト比の小さいTaylor渦流れの流動解析Oral presentation
- 第42回可視化情報シンポジウム, Jul. 2014, Japanese, 可視化情報学会, 東京, Domestic conference超音波パルスドップラ法の速度限界の拡張と高流量計測への適用Oral presentation
- 第42回可視化情報シンポジウム, Jul. 2014, Japanese, 可視化情報学会, 東京, Domestic conference超音波パルスドップラ法における壁面近傍での測定体積による計測速度への影響Oral presentation
- 混相流シンポジウム2014, Jul. 2014, Japanese, 日本混相流学会, 札幌, Domestic conference固体高分子形燃料電池における流路内に滞留する液滴形状と圧力損失Oral presentation
- 第19回動力・エネルギー技術シンポジウム, Jun. 2014, Japanese, 日本機械学会, 福井, Domestic conference固体高分子形燃料電池における流路内の液滴形状と圧力損失評価Oral presentation
- 第51回日本伝熱シンポジウム, May 2014, Japanese, 日本伝熱学会, 浜松, Domestic conference固体高分子形燃料電池における電池内膜厚方向水分布の可視化と計測Oral presentation
- 第51回日本伝熱シンポジウム, May 2014, English, 日本伝熱学会, 浜松, Domestic conferenceMeasurement of subcooled boiling bubbly flow using multiwave ultrasound and damping effectOral presentation
- 日本機械学会関西学生会学生員卒業研究発表講演会, Mar. 2014, Japanese, 日本機械学会関西支部, 堺, Domestic conference水平ダクトにおける気泡通過と壁面せん断応力変化に関する研究Oral presentation
- 日本機械学会関西学生会学生員卒業研究発表講演会, Mar. 2014, Japanese, 日本機械学会関西支部, 堺, Domestic conference固体子分子形燃料電池における流路内液滴挙動と圧力損失評価Oral presentation
- 日本機械学会関西学生会学生員卒業研究発表講演会, Mar. 2014, Japanese, 日本機械学会関西支部, 堺, Domestic conference固体高分子形燃料電池における膜厚方向水輸送現象に関する研究Oral presentation
- 日本機械学会関西学生会学生員卒業研究発表講演会, Mar. 2014, Japanese, 日本機械学会関西支部, 堺, Domestic conferenceパルスドップラ法を用いた超音波流量計の信号処理アルゴリズムに関する研究Oral presentation
- 第91期日本機械学会流体工学部門講演会, Nov. 2013, Japanese, 日本機械学会, 福岡, Domestic conference超音波速度計測によるアスペクト比の小さいTaylor渦流れの流動解析Oral presentation
- 第91期日本機械学会流体工学部門講演会, Nov. 2013, Japanese, 日本機械学会, 福岡, Domestic conference水平管群を横切る気液二相流の管周りボイド率分布計測Oral presentation
- The 12th International Symposium on Fluid Control, Measurement and Visualization, Nov. 2013, English, 奈良市, International conferenceMeasurements of instantaneous velocity profiles of single-phase and two-phase bubbly flow in a vertical pipe using ultrasoundOral presentation
- The Fourth International Symposium on Innovative Nuclear Energy Systems (INES-4), Nov. 2013, English, 東京, International conferenceMEASUREMENT OF BUBBLY TWO-PHASE PIPE FLOW USING MULTIWAVE ULTRASONIC PULSED DOPPLER METHOD AND WIRE MESH TOMOGRAPHYOral presentation
- 第54回電池討論会, Oct. 2013, Japanese, 大阪, Domestic conference固体高分子形燃料電池内におけるGDL内膜厚方向水輸送現象に関する研究Oral presentation
- 日本機械学会2013年度年次大会, Sep. 2013, Japanese, 日本機械学会, 岡山, Domestic conference垂直配管内の二相対向気泡流における超音波計測Oral presentation
- 混相流シンポジウム2013, Aug. 2013, Japanese, 日本混相流学会, 長野, Domestic conference固体高分子形燃料電池の流路内水形状の検討とガス流動解析Oral presentation
- The 10th National Conference on Nuclear Science and Technology, Aug. 2013, English, Vũng Tàu, Vietnum, International conferenceSTUDY OF SINGLE-PHASE AND BUBBLY TWO-PHASE FLOWS IN A VERITICAL PIPE USING ULTRASOUND AND IMAGE PROCESSINGOral presentation
- 第41回可視化情報シンポジウム, Jul. 2013, Japanese, 可視化情報学会, 東京, Domestic conference超音波速度計測によるアスペクト比の小さいTaylor渦流れの流動解析Oral presentation
- 第41回可視化情報シンポジウム, Jul. 2013, Japanese, 可視化情報学会, 東京, Domestic conference超音波パルスドップラ法における速度限界の拡張に関する研究Oral presentation
- 第41回可視化情報シンポジウム, Jul. 2013, Japanese, 可視化情報学会, 東京, Domestic conferenceフェイズドアレイセンサ超音波流速分布計測法による流れ場の可視化Oral presentation
- 第18回動力・エネルギー技術シンポジウム, Jun. 2013, Japanese, 日本機械学会, 千葉, Domestic conference固体高分子形燃料電池の流路内液滴形状の検討とガス流動解析Oral presentation
- 第50回日本伝熱シンポジウム, May 2013, Japanese, 日本伝熱学会, 仙台, Domestic conference固体高分子形燃料電池内におけるMPLによる水輸送現象への影響Oral presentation
- 日本機械学会関西学生会 学生員卒業研究発表会, Mar. 2013, Japanese, 日本機械学会, 大阪市, Domestic conference水平管群を横切る気液二相流の流動計測Oral presentation
- 日本機械学会関西学生会 学生員卒業研究発表会, Mar. 2013, Japanese, 日本機械学会, 大阪市, Domestic conference固体高分子形燃料電池内におけるMPLの有無による膜厚方向水輸送現象への影響評価Oral presentation
- 日本機械学会関西学生会 学生員卒業研究発表会, Mar. 2013, Japanese, 日本機械学会, 大阪市, Domestic conference固体高分子形燃料電池の流路内水形状を考慮したガス流動解析の高度化Oral presentation
- 第53回電池討論会, Nov. 2012, Japanese, 電気化学会, 福岡市, Domestic conference中性子ラジオグラフィを用いたPEFC発電時の膜厚方向水輸送現象の可視化Oral presentation
- 日本機械学会 流体工学部門講演会, Nov. 2012, Japanese, 日本機械学会, 京都市, Domestic conference水平ダクトにおける気泡通過時の壁面せん断応力と液膜厚さ計測Oral presentation
- 日本機械学会2012年度年次大会, Sep. 2012, Japanese, 日本機械学会, 富山市, Domestic conference超音波を用いた流体計測[Invited]Invited oral presentation
- 可視化情報学会 第40回可視化情報シンポジウム, Jul. 2012, English, 可視化情報学会, 東京都, Domestic conferenceマルチウェイブ超音波流速分布計測法を用いた気液二相テイラー渦流れの可視化計測Oral presentation
- 可視化情報学会 第40回可視化情報シンポジウム, Jul. 2012, Japanese, 可視化情報学会, 東京都, Domestic conferenceウェーブレット解析を用いた超音波ドップラ法の信号処理の検討Oral presentation
- 日本機械学会 第17回動力・エネルギー技術シンポジウム, Jun. 2012, Japanese, 日本機械学会, 福岡市, Domestic conference中性子ラジオグラフィを用いたPEFC内における面方向水分布計測と流路‐GDLにおけるガス流動解析Oral presentation
- 日本伝熱学会 第49回日本伝熱シンポジウム, May 2012, Japanese, 日本伝熱学会, 富山市, Domestic conference中性子ラジオグラフィを用いた固体高分子形燃料電池におけるGDL・流路内の滞留水挙動の可視化Oral presentation
- 日本伝熱学会 第49回日本伝熱シンポジウム, May 2012, Japanese, 日本伝熱学会, 富山市, Domestic conference中性子ラジオグラフィによる可変コンダクタンスヒートパイプ（VCHP）の可視化Oral presentation
- 日本機械学会 関西学生会学生員卒業研究発表講演会, Mar. 2012, Japanese, 日本機械学会関西支部, 吹田市, Domestic conferenceStudy on Algorithms of Ultrasonic Doppler Method and Measurements of Fluid FlowOral presentation
- 日本機械学会 関西学生会学生員卒業研究発表講演会, Mar. 2012, Japanese, 日本機械学会関西支部, 吹田市, Domestic conferenceMeasurement of Water Distribution in a Small PEFC by Neutron RadiographyOral presentation
- 日本機械学会 関西学生会学生員卒業研究発表講演会, Mar. 2012, Japanese, 日本機械学会関西支部, 吹田市, Domestic conferenceStudy on Temperature Fluctuation Phenomena and Flow Phenomena in Pressurizer Spray Pipe of Pressurized Water ReactorOral presentation
- 電気化学会 第52回電池討論会, Oct. 2011, Japanese, 電気化学会, 東京都, Domestic conferenceMeasurements of Water Distribution in Through-plane direction of a PEFC by using High Spatial-Resolution System on Neutron RadiographyOral presentation
- 日本混相流学会 年会講演会2011, Aug. 2011, Japanese, 日本混相流学会, 京都市, Domestic conferenceMeasurement of void fraction in subcooled boiling by neutron radiographyOral presentation
- Proc. of Int. Conf. on Advanced Technology in Experimental Mechanics 2011 (ATEM’11), Aug. 2011, English, 日本機械学会, 神戸市, International conferenceQuantitative Measurements of Water Distribution in a PEFC by using Neutron Radiography and Analysis of Gas-velocity DistributionsOral presentation
- 日本機械学会 第16回動力・エネルギー技術シンポジウム, Jun. 2011, Japanese, 日本機械学会, 吹田市, Domestic conferenceThree-Dimensional Visualization and Measurement of Water Distributions in PEFC by Dynamic CT Method on Neutron RadiographyOral presentation
- 日本機械学会 第16回動力・エネルギー技術シンポジウム, Jun. 2011, Japanese, 日本機械学会, 吹田市, Domestic conferenceMeasurement of water distribution by using neutron radiography and network analysis of gas-velocity distributions in a PEFCOral presentation
- 日本機械学会関西学生会学生員卒業研究発表講演会, Mar. 2011, Japanese, 日本機械学会関西支部, 京都市, Domestic conference中性子ラジオグラフィを用いたPEFC内における水分布の可視化・計測Oral presentation
- 日本機械学会関西学生会学生員卒業研究発表講演会, Mar. 2011, Japanese, 日本機械学会関西支部, 京都市, Domestic conference中性子ラジオグラフィによる固体高分子型燃料電池内水分布計測Oral presentation
- 日本機械学会関西支部第86期定時総会講演会, Mar. 2011, Japanese, 日本機械学会関西支部, 京都市, Domestic conferenceStudy on Freezing Phenomena of Water in a Porous Layer Used as Gas Diffusion Layer in PEFCOral presentation
- 日本機械学会関西学生会学生員卒業研究発表講演会, Mar. 2011, Japanese, 日本機械学会関西支部, 京都市, Domestic conference水平ダクト内気液二相流における壁面せん断応力と流動に関する研究Oral presentation
- 日本機械学会関西学生会学生員卒業研究発表講演会, Mar. 2011, Japanese, 日本機械学会関西支部, 京都市, Domestic conference界面活性剤溶液の摩擦損失低減効果と熱伝達特性Oral presentation
- 第51回電池討論会, Oct. 2010, Japanese, 電気化学会, 名古屋市, Domestic conference中性子ラジオグラフィを用いたダイナミックCT計測による固体高分子形燃料電池内水挙動の三次元可視化Oral presentation
- 第51回電池討論会, Oct. 2010, Japanese, 電気化学会, 名古屋市, Domestic conference中性子ラジオグラフィを用いたPEFC内の水分布計測と気流分布解析Oral presentation
- 日本混相流学会 年会講演会2010, Jul. 2010, Japanese, 日本混相流学会, 浜松市, Domestic conferenceFlow Measurement of Air-Liquid Two-Phase Flow in Horizontal Duct by using Ultrasonic Velocity Profile MethodOral presentation
- 日本混相流学会 年会講演会2010, Jul. 2010, Japanese, 日本混相流学会, 浜松市, Domestic conferenceIdentification Method of Liquid-Gas Interface for Measuring Two-Phase Flow by using Ultrasonic Velocity Profile MethodOral presentation
- 日本混相流学会 年会講演会2010, Jul. 2010, Japanese, 日本混相流学会, 浜松市, Domestic conferenceA Thermal-Hydraulic Design of a Small Accelerator Target for a Compact Neutron SourceOral presentation
- 日本機械学会 第15回動力・エネルギー技術シンポジウム, Jun. 2010, Japanese, 日本機械学会, 東京都, Domestic conference中性子ラジオグラフィを用いたダイナミックCT技術によるPEFC内水分布の可視化Oral presentation
- 第17回燃料電池シンポジウム, May 2010, Japanese, 燃料電池開発情報センター, 東京都, Domestic conference中性子ラジオグラフィを用いたPEFC内水分布の計測と気流分布解析Oral presentation
- 日本機械学会関西学生会学生員卒業研究発表会, Mar. 2010, Japanese, 日本機械学会, 神戸市, Domestic conferenceDevelopment of a measurement technique for two-phase flow using an ultrasonic methodOral presentation
- 日本機械学会関西学生会学生員卒業研究発表会, Mar. 2010, Japanese, 日本機械学会, 神戸市, Domestic conferenceThree-Dimensional Visualization of Water Behavior in PEFC by Neutron RadiographyOral presentation
- 日本機械学会関西学生会学生員卒業研究発表会, Mar. 2010, Japanese, 日本機械学会, 神戸市, Domestic conferenceMeasurement of Distribution of Water of Thickness Direction in PEFC by Neutron RadiographyOral presentation
- 日本機械学会関西学生会学生員卒業研究発表会, Mar. 2010, Japanese, 日本機械学会, 神戸市, Domestic conferenceA thermal design of compact producing target for accelerator,Oral presentation
- 日本機械学会関西学生会学生員卒業研究発表会, Mar. 2010, Japanese, 日本機械学会, 神戸市, Domestic conferenceStudy on Drag Reducing Surfactant SolutionOral presentation
- 日本機械学会熱工学コンファレンス2009, Nov. 2009, Japanese, 日本機械学会, 宇部市, Domestic conferenceMeasurement of Distribution of Water of Thickness Direction in PEFC by Neutron RadiographyOral presentation
- 日本機械学会熱工学コンファレンス2009, Nov. 2009, Japanese, 日本機械学会, 宇部市, Domestic conferenceStudy on the Heat Transfer Characteristics for Drag Reduction Surfactant SolutionOral presentation
- 日本混相流学会年会講演会 2009, Aug. 2009, Japanese, 日本混相流学会, 熊本市, Domestic conferenceStudy on drag reduction effectsOral presentation
- 日本混相流学会年会講演会 2009, Aug. 2009, Japanese, 日本混相流学会, 熊本市, Domestic conferenceStudy on Temperature Fluctuation Phenomena in a Branch Pipe of Nuclear ReactorOral presentation
- 日本混相流学会年会講演会 2009, Aug. 2009, Japanese, 日本混相流学会, 熊本市, Domestic conferenceStudy on temperature fluctuation phenomena in pressurizer bent pipe of pressurized water reactorOral presentation
- ヒートパイプ協会 総会講演会, Jul. 2009, Japanese, ヒートパイプ協会, 東京, Domestic conferenceVisualization and Measuremnt of Refrigerant Behavior in Heat PipesInvited oral presentation
- 日本伝熱学会 第46回日本伝熱シンポジウム, Jun. 2009, Japanese, 日本伝熱学会, 京都市, Domestic conferenceDevelopment of a Method for Stable Behavior of a Variable Conductance Heat Pipe - 1st report; Visualization of refrigerant behavior by neutron radiographyOral presentation
- 日本伝熱学会 第46回日本伝熱シンポジウム, Jun. 2009, Japanese, 日本伝熱学会, 京都市, Domestic conferenceDevelopment of a Method for Stable Behavior of a Variable Conductance Heat Pipe - 1st report; Evaluation of effect of gas-liquid separatorOral presentation
- 日本機械学会関西学生会学生員卒業研究発表会, Mar. 2009, Japanese, 日本機械学会関西支部, 東大阪市, Domestic conference中性子ラジオグラフィによる高空間分解能定量計測技術の開発Oral presentation
- 日本機械学会関西学生会学生員卒業研究発表会, Mar. 2009, Japanese, 日本機械学会関西支部, 東大阪市, Domestic conference中性子ラジオグラフィによるダイナミックCT計測技術の開発Oral presentation
- 日本機械学会関西学生会学生員卒業研究発表会, Mar. 2009, Japanese, 日本機械学会関西支部, 東大阪市, Domestic conference水平ダクト内二相流の流動計測に関する研究Oral presentation
- 日本機械学会関西学生会学生員卒業研究発表会, Mar. 2009, Japanese, 日本機械学会関西支部, 東大阪市, Domestic conference加速器ターゲットにおける沸騰熱伝達および圧力損失特性Oral presentation
- 日本機械学会関西支部第84期定時総会講演会, Mar. 2009, Japanese, 日本機械学会関西支部, 東大阪市, Domestic conferenceA study of thermal hydraulics in the target for acceleratorOral presentation
- The 6th Int. Topical Meeting on Neutron Radiography, Sep. 2008, English, Int. Society for Neutron Radiography, Kobe, International conferenceVisualization of Oil Behavior in a Small 4-cycle Engine by Electrical MotoringPoster presentation
- The 6th Int. Topical Meeting on Neutron Radiography, Sep. 2008, English, Int. Society for Neutron Radiography, Kobe, International conferenceThree-Dimensional Observation of Water Distribution in PEFC by Neutron CTPoster presentation
- The Second Int. Forum on Heat Transfer, Sep. 2008, English, Heat Transfer Society of Japan, Tokyo, International conferenceMultidimensional Analysis of Developing Two-phase Flows using Multidfield Simulation in Natural Circulation BWR ChimneyPoster presentation
- The 6th Int. Topical Meeting on Neutron Radiography, Sep. 2008, English, Int. Society for Neutron Radiography, Kobe, International conferenceFlow Visualization of Refrigerant in a Self-Vibration Heat Pipe by Neutron RadiographyPoster presentation
- The 6th Int. Topical Meeting on Neutron Radiography, Sep. 2008, English, Int. Society for Neutron Radiography, Kobe, International conferenceEvaluation of Water Distribution Effect on Performances of JARI Standard PEFC by using Neutron RadiographyOral presentation
- 第45回アイソトープ・放射線研究発表会, Jul. 2008, Japanese, 日本アイソトープ協会, 東京, Domestic conferenceVisualization and Measurement of Water Distribution in JARI Standard PEFC by using Neutron RadiographyOral presentation
- 第45回日本伝熱シンポジウム, May 2008, Japanese, 日本伝熱学会, つくば市, Domestic conferenceVisualization of a self-vibration heat pipe by neutron radiographyOral presentation
- 第45回日本伝熱シンポジウム, May 2008, Japanese, 日本伝熱学会, つくば市, Domestic conferenceCorrelation between Change in Cell Voltage and Pressure Drop, and Water Distribution in PEFC(In-situ visualization and measurement by neutron radiography)Oral presentation
- 日本機械学会関西学生会学生員卒業研究発表会, Mar. 2008, Japanese, 日本機械学会, 吹田市, Domestic conferenceVisualization and measurement of water distribution in PEFC by Neutron RadiographyOral presentation
- 日本機械学会関西学生会学生員卒業研究発表会, Mar. 2008, Japanese, 日本機械学会, 吹田市, Domestic conferenceVisualization and measurement of water distribution in PEFC by Neutron RadiographyOral presentation
- 日本機械学会関西学生会学生員卒業研究発表会, Mar. 2008, Japanese, 日本機械学会, 吹田市, Domestic conferenceStudy on thermal hydraulics phenomena in a pulsating heat pipeOral presentation
- 日本機械学会関西学生会学生員卒業研究発表会, Mar. 2008, Japanese, 日本機械学会, 吹田市, Domestic conferenceStudy on drag reduction by micro bubbleOral presentation
- 日本機械学会関西支部秋季技術フォーラム, Oct. 2007, Japanese, 日本機械学会, 京田辺市, Domestic conference多流体モデルを用いたESBWRライザー部の多次元二相流動解析Oral presentation
- The 12th National Symposium of Power and Energy Systems, Jun. 2007, Japanese, Tokyo, Domestic conferenceTrial measurement on two-phase flow using a multi-wave ultrasonic velocity profile method (3rd report: Measurement of Slug Flow and Visualization using High-speed Camera)Oral presentation
- Japan Society of Multiphase Flow Annual Meeting 2007, Jun. 2007, Japanese, Sapporo, Domestic conferenceMeasurement of bubbly flow in rectangular channel using multi-wave ultrasonic methodOral presentation
- Japan Society of Multiphase Flow Annual Meeting 2006, Aug. 2006, Japanese, Kanazawa, Domestic conferenceApplication of multiple measurement system using ultrasound, electrical conduction and image processing for two-phase flow measurementOral presentation
- The Japan Society of Mechanical Engineers Fluids Engineering Conference 2005, Oct. 2005, Japanese, Kanazawa, Domestic conferenceDevelopment of a measurement technique for multi-phase flow using a multi-wave ultrasonic methodOral presentation
- Japan Society of Multiphase Flow (JSMF) Annual Meeting 2005, Aug. 2005, Japanese, Tokyo, Domestic conferenceDevelopment of simultaneous measurement system for bubbly flow using multi-wave TDXOral presentation
- The 10th National Symposium of Power and Energy Systems, Jun. 2005, Japanese, Nagasaki, Domestic conferenceTrial measurement on two-phase flow using a multi-wave ultrasonic velocity profile method (2nd Report, ultrasound time domain correlation method for bubble rising velocity)Oral presentation
- 日本機械学会2004年度年次大会講演論文集, Sep. 2004ワイヤーメッシュ・トモグラフィ法を用いた鉛直円管における気泡流の発達に関する研究Oral presentation
- 日本混相流学会年会講演会2004講演論文集, Aug. 2004二重円筒型気泡発生装置の性能評価Oral presentation
- 第9回動力・エネルギー技術シンポジウム講演論文集, Jun. 2004マルチウェイブ超音波流速分布計測法を用いた気液二相流動計測の試みOral presentation
- 日本混相流学会年会講演会2003, Jul. 2003超音波とワイヤーメッシュトモグラフィー法を用いた鉛直矩形管における気泡流計測Oral presentation
- 日本混相流学会年会講演会2002, Jul. 2002超音波流速分布計を用いた気液二相流におけるレイノルズ応力の計測Oral presentation
- 日本混相流学会年会講演会2001, Jul. 2001超音波流速分布計測計を用いた気液二相流計測における測定体積の影響Oral presentation
- 日本原子力学会 2001年春の大会, Mar. 2001超音波流速分布計測法(UVP)を用いた気泡流の計測(上昇気泡流計測手法の高度化)Oral presentation
■ Research Themes- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Kobe University, Apr. 2021 - Mar. 2024Modeling of liquid metal two-phase flow under influence of magnetic field using high-speed ultrasonic tomography申請者が開発した超音波トモグラフィ法を用いて、ガリウム合金中を上昇する連続気泡を対象に、気泡径、気泡間隔および水平磁場印加時の気泡挙動を実験的に評価することを目的に、研究を実施した。 本年度は試験体系を検討し、連続鋳造で使用されている磁場制御条件も参考に、水平磁場を400mT以上印加するものとした。さらに試験部として、内径50mmの円筒容器とすることで、直径250mm以上の領域において均一な水平磁場を印加可能な電磁石を選定した。液体金属中を上昇する連続気泡にって生じる後流渦の影響を評価するためには、同一の気泡径において異なる気泡離脱周期を実現する気泡発生部が必要となる。そこで、スピーカーを用いた音圧変動を利用することで気泡離脱周期を可変とする気泡注入部を製作し、ガリウム合金への適用性についてX線ラジオグラフィおよび超音波トモグラフィ法で評価した。それにより気泡生成周波数が5Hzまでの条件において、等価径が均一な連続気泡を生成可能であることを確認した。さらに円筒容器において、単一および連続して気泡を上昇させ、断面ボイド分布の連続CT計測を行った。容器底部から20mmの位置を入口条件とし、計測位置140mmの位置において、20mmの位置からのボイド分布の変化を評価することで、気泡離脱周期の違いが及ぼす気泡分散への影響について評価した。更に容器底部に設置した超音波センサを用いて、ドップラ法による速度計測を行った。その結果、磁場強度が弱い条件では、磁場強度を増加させるにつれて気泡上昇速度が増加し、磁場強度を更に増加させると気泡上昇速度が低下することを示した。トモグラフィ計測による結果でも、磁場強度を増加するにつれて、連続する気泡がほぼ同じ計測断面を通過することが示され、気泡通過間隔も一定となることを実験的に示した。
- 科学研究費補助金／基盤研究(B), Apr. 2017 - Mar. 2020, Principal investigatorCompetitive research funding
- 日本学術振興会, 学術研究助成基金助成金／国際共同研究加速基金(国際共同研究強化), 国際共同研究加速基金(国際共同研究強化), 神戸大学, 2018 - 2020, Principal investigator本研究では、広角超音波センサを8個使用し、50mm程度の配管において瞬時ボイド分布を計測可能とした。構築した超音波トモグラフィ計測システムでは、各センサの超音波送受信を高速に切り替えることで、気液界面によって生じる超音波の反射信号を取得する。全センサにおいて計測された反射信号を用いてボイド分布再構成法を構築し、一断面の計測に要する時間分解能として1ミリ秒を達成した。これを500フレーム毎秒で連続CT計測を行うことで、気泡の形状やボイド分布の計測を実現した。液体金属中を上昇する連続気泡にって生じる後流渦の影響を評価するために、同一の気泡径において異なる気泡離脱周期を実現する気泡発生部が必要となる。そこで、スピーカーを用いた音圧変動によって気泡離脱周期を可変とする気泡注入部を製作し、ガリウム合金への適用性について、超音波トモグラフィおよびX線ラジオグラフィを用いることで評価した。さらに内径50mmの円筒容器において、単一および連続して気泡を上昇させ、断面ボイド分布の連続CT計測を行った。CT計測を容器底部から20mmおよび140mmの位置において実施することで、気泡離脱周期の違いが及ぼす気泡分散への影響について評価した。更に容器上部に設置した超音波センサを用いて、ドップラ法による速度計測を行った。 体積等価気泡径が約9mmのガリウム合金中を上昇する連続気泡中において、気泡離脱周期を1～5Hzに変化させところ、3Hz以下の条件では、連続する気泡がほぼ同一の断面を通過したのに対し、周期を短くすることで、計測断面において各気泡の通過位置のバラつきが大きくなることを示した。すなわち、気泡離脱周期を大きくすることで、異なる軌跡において気泡が上昇したと考えられる。Competitive research funding
- 学術研究助成基金助成金／基盤研究(C), Apr. 2016 - Mar. 2019Competitive research funding
- 学術研究助成基金助成金／基盤研究(C), Apr. 2014 - Mar. 2017, Principal investigatorCompetitive research funding
- 科学研究費補助金／基盤研究(B), 2013 - 2015Competitive research funding
- 科学研究費補助金／若手研究(B), Apr. 2012 - Mar. 2014, Principal investigatorCompetitive research funding
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Tokyo Institute of Technology, Apr. 2010 - Mar. 2013A phased array Ultrasonic inspection flow rate measurement system was developed. This measurement system employs phased array technique to reduce noise from multiple reflections which occurs in a wedge. However, phased array technique has several difficulties one of them is about grating lobes. Thus, the array sensor was designed to reduce the grating lobes using numerical analysis. Performance of the manufactured array sensor was evaluated by experimental measurements of sound pressure distribution emitted from the array sensor, and optimal parameters to control the array sensor were obtained. Hardware with a 8-channel pulser/receiver and a PC with A/D converter, and software of the ultrasonic velocity profile measurement system with a phased array sensor were also developed. The software is based on ultrasonic Doppler method with autocorrelation method.Competitive research funding
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (B), Kobe University, 2009 - 2010, Principal investigatorA system of ultrasonic velocity profiler was developed by using an ultrasonic pulser/receiver, a high-speed digitizer and a PC. Velocity distributions in single-phase flow could be measured accurately by using the system. It was shown that the identification of liquid-gas interface was possible based on the phase change of the reflected signal on the interface. The system could be synchronized with a high-speed camera, and it was shown that the liquid velocity distributions around a bubble could be measured by using the developed system.Competitive research funding
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Kobe University, 2008 - 2010Studies were carried out on optimized design of accelerator target for a small size neutron source. Following results were obtained : Neutron yield by using a Lithium target was higher than that using a Beryllium target. The liquid Lithium target was considered since solid Lithium was not suitable for the target due to gas production. The liquid Lithium layer thicker than 70μm was required for a 2.5MeV proton beam. A role-up method by a disk was proposed and the layer around 300μm could be formed.Competitive research funding
- 日本学術振興会, 科学研究費補助金／若手研究(スタートアップ), 若手研究(スタートアップ), 神戸大学, 2008 - 2009, Principal investigator超音波パルサレシーバを新たに導入し,高速デジタイザを用いた混相流動解析システムの一部を構築した.パルサレシーバによって送受信された超音波信号は流体中の微粒子または気泡によって反射し,高速デジタイザによってサンプリングされる.一定数の波形をオンボードメモリに蓄積後PCに転送され,波形解析することで測定線上の瞬時速度分布を取得可能とした.取得した波形および算出速度はオンタイムにPC上で確認可能とし,更に取得データの精度向上のためフィルタ処理などのアルゴリズムを導入可能としている.速度解析アルゴリズムには相関法,およびドップラ法を選択的に用いるシステムとした.相関法では,二つの超音波パルスによって瞬時速度が得られるため1ミリ秒オーダの高時間分可能を有する.一方ドップラ法では,連続した32〜128の超音波パルスからドップラ周波数を算出するため,比較的ノイズに強いといった特徴を有する.これらを適切に選択することで流れ場特性に応じて速度算出アルゴリズムを選択可能としている.更に,速度が急峻に変化する乱流場での精度向上を目指し,ドップラ解析手法に従来のFFTに加えウェーブレット解析の導入を検討し,乱流場での精度向上を目指している.これらシステムの有効性評価のため,幅50mm,高さ25mm,長さ3000mmのアクリル製水平矩形流路を製作した.流路入口には直径1mmの気泡注入口3個を上部に設置し,上部噴出し気泡による気液二相流を発生可能としている.本試験装置では開発したシステムと比較計測を行うため,既存のレーザドップラ流速計による液相速度分布計測,ならびにハイスピードカメラによる気泡流動挙動計測が可能であり,次年度に計測を行う予定である.Competitive research funding
- 2008, Principal investigator先進的原子炉に関する国際会議Competitive research funding
- 日本学術振興会, 特別研究員奨励費, 特別研究員奨励費, 神戸大学, 2007 - 2007, Principal investigatorCompetitive research funding
- 日本学術振興会, 特別研究員奨励費／科学研究費補助金, 特別研究員奨励費, 東京工業大学, Apr. 2005 - Mar. 2006, Principal investigator二相流動を正確に予測する上で,気泡速度分布計測および気泡周りの液相速度分布計測は重要であるが,その実験の困難さから更なる実験的解明が要求されている.そこで著者らによって昨年度までに開発した同軸二波長超音波センサ(マルチウェイブ・トランスデューサ)を用い,マルチウェイブで気泡・液相速度分布を同時計測するマルチウェイブ超音波法の開発を行った.超音波の反射強度は媒質である水と反射体との反射係数に依存する.従来用いていた超音波流速分布計測計(UVP)では,装置の制約によって気泡・液相の同時速度分布取得は不可能であった.そこで液相のトレーサ粒子と気液界面における反射強度の差異に注目し,異なる超音波基本周波数による反射信号を用いたデータ処理を独自開発することによって,気泡・液相の同時速度分布計測を可能とした.従来のUVP法ではドップラ信号による速度算出を行うため,最低32回の超音波送受信が必要である.それに対して本手法で用いだ相関法は,最低2回の超音波送受信によって速度算出が可能であることから,高時間分解能での計測が可能であることが特徴である.そこで開発した本手法を鉛直円管内気泡流に適用することによって,気液の速度分布計測が可能であることを示した.更にハイスピードカメラによる画像取得とマルチウェイブ超音波法を同期させることによってスラグ流周りの液相速度分布計測を可能とした.また,これらの実験データを米国Rensselaer Polytechnic Instituteにて開発された多流体三次元解析コード(NPHASE)に適用し,SBWR内ライザ部における二相流動解析を実現させた.Competitive research funding
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