Tomio OKAWA

Department of Mechanical and Intelligent Systems EngineeringProfessor
Cluster III (Fundamental Science and Engineering)Professor
Researcher Information

Degree

  • Master of Engineering, Tokyo Institute of Technology
  • Doctor of Engineering, Tokyo Institute of Technology

Research Keyword

  • thermal-hydraulics
  • Energy and Environment
  • boiling heat transfer
  • 気液二相流
  • Nuclear Engineering

Field Of Study

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Thermal engineering
  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Fluid engineering
  • Energy, Nuclear engineering

Career

  • Oct. 2011 - Present
    The University of Electro-Communications, 教授
  • Oct. 2011 - Mar. 2013
    Osaka University, 招聘教授
  • Apr. 2007 - Sep. 2011
    Osaka University, Associate Professor
  • Jun. 2002 - Mar. 2007
    Osaka University, Associate Professor
  • Mar. 1999 - May 2002
    Osaka University, Lecturer
  • Jan. 1997 - Feb. 1999
    Central Research Institute of Electric Power Industry, 主任研究員
  • Aug. 1992 - Dec. 1996
    Central Research Institute of Electric Power Industry, 担当研究員
  • Apr. 1990 - Jul. 1992
    Central Research Institute of Electric Power Industry, Researcher

Educational Background

  • Apr. 1988 - Mar. 1990
    Tokyo Institute of Technology, Graduate School of Science and Engineering, Department of Nuclear Engineering
  • Apr. 1984 - Mar. 1988
    Tokyo Institute of Technology, School of Science, 応用物理学科, Japan
  • Apr. 1981 - Mar. 1984
    千葉県立船橋高等学校

Member History

  • Apr. 2025 - Present
    委員長, 日本機械学会動力エネルギーシステム部門部門賞委員会, Society
  • Dec. 2024 - Present
    代表会員, 日本機械学会, Society
  • 2023 - Present
    国際企画委員, 日本機械学会動力システム部門, Society
  • 2022 - Present
    委員, 日本原子力学会標準委員会システム安全専門部会炉心燃料分科会
  • 2022 - Present
    第30回原子力工学国際会議組織委員長, 日本機械学会, Society
  • 2021 - Present
    専門委員, 独立行政法人大学改革支援・学位授与機構 学位審査会
  • 2020 - Present
    委員長, 日本ボイラ協会ボイラー構造委員会
  • 2020 - Present
    委員, 日本原子力研究開発機構炉心安全・熱流動分科会
  • 2020 - Present
    委員, 日本原子力研究開発機構安全研究専門委員会
  • 2020 - Present
    部門賞委員, 日本機械学会動力システム部門, Society
  • 2019 - Present
    運営委員, 日本機械学会動力システム部門, Society
  • Apr. 2024 - Mar. 2025
    部門長, 日本機械学会動力・エネルギーシステム部門, Society
  • Aug. 2022 - Jul. 2024
    編集委員長, 日本混相流学会
  • Apr. 2023 - Mar. 2024
    部会長, 日本原子力学会熱流動部会, Society
  • Apr. 2023 - Mar. 2024
    副部門長, 日本機械学会動力エネルギーシステム部門, Society
  • Apr. 2023 - Mar. 2024
    総務委員長, 日本機械学会動力エネルギーシステム部門, Society
  • 2022 - 2023
    副部会長, 日本原子力学会熱流動部会
  • 2022 - 2023
    理事・情報部会長, 日本混相流学会
  • 2022 - 2023
    計算力学技術者資格認定委員会1級混相流WG主査, 日本機械学会, Society
  • 2019 - 2023
    国際企画委員長, 日本機械学会動力システム部門, Society
  • 2021 - 2022
    第12回原子炉熱流動と安全に関する日韓シンポジウム組織委員長, 日本原子力学会
  • 2018 - 2022
    委員長, 日本原子力学会原子炉における機構論的限界熱流束評価技術研究専門委員会, Society
  • 2019 - 2020
    フェロー賞選考委員, 日本機械学会
  • 2020
    熱水力安全評価基盤技術高度化戦略マップ検討ワーキンググループ委員, 日本原子力学会熱流動部会
  • 2004
    広報委員長, 日本原子力学会熱流動部会, Society, 日本原子力学会熱流動部会広報委員会
  • 1997 - 1999
    編集委員, 日本混相流学会, Society, 日本混相流学会
Research Activity Information

Award

  • Nov. 2024
    日本機械学会動力エネルギーシステム部門
    JSME Series in Thermal and Nuclear Power Generation出版を通じての技術継承活動
    貢献表彰
  • Mar. 2024
    日本原子力学会
    フェロー賞（指導学生による受賞：名手海人）
  • Mar. 2024
    日本原子力学会熱流動部会
    優秀講演賞賞（指導学生による受賞）辻村玲摩
  • Sep. 2023
    日本原子力学会熱流動部会
    優秀講演賞賞（日本原子力学会2023年春の年会）（指導学生による受賞）Raka Firman Baskara Permana
  • Mar. 2023
    日本原子力学会
    フェロー賞（指導学生による受賞） 柳田大智
  • Mar. 2022
    日本原子力学会
    フェロー賞（指導学生による受賞）田渕純平
  • Mar. 2022
    日本原子力学会
    フェロー賞（指導学生による受賞）辻村玲摩
  • Mar. 2022
    日本原子力学会
    Experimental Study on Onset Condition of Boiling Entrainment from Falling Liquid Film with Gas Sheared Flow
    「学生ポスターセッション博士学生優秀賞」（指導学生による受賞）Raka Firman Baskara Permana
  • Mar. 2022
    日本原子力学会
    熱流動部会奨励賞（指導学生による受賞）梅原裕太郎
  • Mar. 2022
    日本原子力学会熱流動部会
    核沸騰による流下液膜からの液滴飛散開始条件に関する実験的検討
    優秀講演賞賞（日本原子力学会2021年度秋の大会）（指導学生による受賞）田渕純平
  • 1996
    日本機械学会動力エネルギーシステム部門優秀講演論文賞
    Japan
  • 1996
    日本混相流学会論文賞
    Japan

Paper

  • Development of the AI-assisted Thermal Hydraulic Analysis Method for Condensing Bubbles in Vertical Subcooled Flow Boiling
    Wen Zhou; Shuichiro Miwa; Ryoma Tsujimura; Thanh-Binh Nguyen; Tomio Okawa; Koji Okamoto
    International Journal of Multiphase Flow, Elsevier BV, 105246-105246, Apr. 2025, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Boiling Heat Transfer Coefficient of Hybrid Nanofluids with and without Surfactant
    Muhamad Zuhairi Sulaiman; Stephen Wong Teck Ching; Heng Zeng Hui; Azim Arshad; Tomio Okawa
    Journal of Advanced Research in Micro and Nano Engineering, Akademia Baru Publishing, 27, 1, 31-41, 05 Dec. 2024, Peer-reviwed, Experiments were carried out to investigate the effect of surfactants on the boiling heat transfer coefficient of hybrid water-based nanofluids. In the present work, both Al2O3-SiO2 and Al2O3-TiO2 hybrid nanofluids were prepared with a 75:25 composition ratio and concentration of 0.01 v/v%, mixed with SDS surfactant of 40 ppm and prepared using ultrasonic process. It was found that Al2O3-SiO2 and Al2O3-TiO2 hybrid nanofluid enhance BHTC performance compared with distilled water, however, its performance will deteriorate gradually after 5 minutes of the experiment. Additional SDS in both Al2O3-SiO2-SDS/Water and Al2O3-TiO2-SDS/Water hybrid nanofluid will increase its BHTC performances up to 112.27% and 127.03% respectively compared with distilled water. Al2O3-SDS has better BHTC performance compared with Al2O3-SiO2 and Al2O3-TiO2 hybrid nanofluid which is 327.15% compared with distilled water.
    Scientific journal, English
    URL
    DOI URL
  • Experimental validation of positive relationship between the heat fluxes at departure from nucleate boiling and large bubble formation
    Thanh-Binh Nguyen; Ryoma Tsujimura; Tomio Okawa
    Last, International Journal of Heat and Mass Transfer, Elsevier BV, 234, 126107-126107, Dec. 2024, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Interaction between thermal-hydraulic phenomena and structural integrity of plant components
    Tomio Okawa
    Lead, Proceedings of 14th Asia-Pacific Conference on Fracture and Strength (APCFS 2024), 25 Nov. 2024, Invited
    International conference proceedings, English
  • Visualization and Phenomenological Modeling of Subcooled Flow Boiling
    Tomio Okawa
    Lead, Proceedings of Advances in Thermal Hydraulics (ATH 2024), 19 Nov. 2024, Invited
    International conference proceedings, English
    共同研究・競争的資金等URL
  • Introduction of the Activities of THD of AESJ
    Tomio Okawa
    Lead, Proceedings of Advances in Thermal Hydraulics (ATH 2024), 18 Nov. 2024, Invited
    International conference proceedings, English
  • An Experimental Study of Rapid Cooling of High-Temperature Bodies by Nanofluids
    Som Onn Ouch; Tomio Okawa
    Last, Proceedings of 13th Korea-Japan Nuclear Thermal Hydraulics and Safety Symposium (NTHAS 13), 11 Nov. 2024, Peer-reviwed
    International conference proceedings, English
    共同研究・競争的資金等URL
  • Experimental Verification of the Effect of Nanomaterials on the OSV Occurrence Time
    Yue Wang; Thanh-Binh Nguyen; Yudai Tsutsui; Tomio Okawa
    Last, Proceedings of 13th Korea-Japan Nuclear Thermal Hydraulics and Safety Symposium (NTHAS 13), 11 Nov. 2024, Peer-reviwed
    International conference proceedings, English
  • Development of Boiling Entrainment Rate Model from a Falling Liquid Film on a Heated Surface
    Raka Firman; Baskara Permana; Kaito Nade; Tomio Okawa; Yuki Narushima; Hajime Furuichi; Kenichi Katono
    Corresponding, Proceedings of 13th Korea-Japan Nuclear Thermal Hydraulics and Safety Symposium (NTHAS 13), 11 Nov. 2024, Peer-reviwed
    International conference proceedings
    共同研究・競争的資金等URL
  • Onset of Splashing During Single Drop Impact onto a Stationary Liquid Film
    Tomio Okawa
    Lead, Proceedings of 2nd International Conference on Catalysis, Chemical Engineering, Nov. 2024
    International conference proceedings, English
  • Numerical study on the effects of tube inclination angle and heat conductive cover plate on freeze plug performance in molten salt reactors
    Muhammad Ilham; Indarta Kuncoro Aji; Tomio Okawa
    Last, Nuclear Engineering and Design, Elsevier BV, 428, 113528-113528, Nov. 2024, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Experimentation and Modeling of Subcooled Flow Boiling from the Perspective of Large Bubble Formation
    Tomio Okawa; Thanh-Binh Nguyen; Ryoma Tsujimura
    Lead, Proceedings of 14th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation, and Safety (NUTHOS-14), 198-209, 27 Aug. 2024, Peer-reviwed
    International conference proceedings, English
    共同研究・競争的資金等URL
  • The Eff ect of Liquid and Wall Properties Toward the Increase of Wetting Velocity in the Case of Using Multiple Plates in the Top-Refl ood Vertical Surfaces
    Akbari; Tomio Okawa
    Last, Proceedings of 31st International Conference on Nuclear Engineering, 06 Aug. 2024, Peer-reviwed
    International conference proceedings, English
  • The Robust Development of a Thermal Hydraulic Analysis Method for Condensation Bubbles in Subcooled Flow Boiling Using AI Based Object Detection and Tracking Technique
    Wen Zhou; Shuichiro Miwa; Koji Okamoto; Tomio Okawa; Ryoma Tsujimura; Thanh-Binh Nguyen
    Proceedings of 31st International Conference on Nuclear Engineering, Aug. 2024, Peer-reviwed
    International conference proceedings, English
    共同研究・競争的資金等URL
  • Interference effect of nearby nucleation sites on bubble release frequency in subcooled flow boiling
    Ryoma Tsujimura; Tomio Okawa
    Last, Applied Thermal Engineering, Elsevier BV, 247, 123078-123078, Jun. 2024, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Bubble feature extraction in subcooled flow boiling using AI-based object detection and tracking techniques
    Wen Zhou; Shuichiro Miwa; Ryom Tsujimura; Thanh-Binh Nguyen; Tomio Okawa; Koji Okamoto
    International Journal of Heat and Mass Transfer, 222, 125188, 01 May 2024, Peer-reviwed
    Scientific journal, English
    共同研究・競争的資金等URL
  • Experiments on the onset of boiling entrainment from a falling liquid film with gas sheared flow
    Raka Firman Baskara Permana; Junpei Tabuchi; Yuki Narushima; Hajime Furuichi; Tomio Okawa; Kenichi Katono
    Corresponding, International Journal of Heat and Mass Transfer, 220, 125006, Mar. 2024, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Experimental validation of the mechanism and condition for the onset of significant void in subcooled flow boiling
    Thanh Binh Nguyen; Tomio Okawa
    Last, International Journal of Heat and Mass Transfer, 219, 124881, Feb. 2024, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Effects of nozzle orifice shape on jet breakup and splashing during liquid jet impact onto a horizontal plate
    Guofu Sun; Yi Zhan; Tomio Okawa; Mitsuhiro Aoyagi; Akihiro Uchibori; Yasushi Okano
    Corresponding, Experimental Thermal and Fluid Science, 151, 111095, 01 Feb. 2024, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Semi-mechanistic prediction of DNB heat flux based on global bubble coalescence concept
    Thanh-Binh Nguyen; Tomio Okawa
    Last, International Journal of Thermal Sciences, Elsevier BV, 195, 108646-108646, Jan. 2024, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Applications of nano particle sol for capillary-driven heat pipe
    Yifan Liu; Menglei Wang; Yutaro Umehara; Tomio Okawa; Daisuke Shimizu
    Proceedings of 33rd International Symposium on Transport Phenomena (ISTP-33), No. 150, Sep. 2023, Peer-reviwed
    International conference proceedings, English
  • A study on boiling entrainment from a liquid film on a heated surface
    Raka Firman B; Tomio Okawa; Yuki Narushima; Hajime Furuichi; Kenichi Katono
    Proceeding of 20th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Aug. 2023, Peer-reviwed
    International conference proceedings, English
  • A Simple Analytical Model to Predict the Freeze Plug Opening Time in Molten Salt Reactors
    Muhammad Ilham; Tomio Okawa
    Last, Journal of Nuclear Engineering and Radiation Science, ASME International, 9, 4, 1-11, 30 Jun. 2023, Peer-reviwed
    Scientific journal, English
    URL
    DOI URL
  • Experiments on thermal performance of heat pipes using nanoparticle layer as the wick
    Menglei Wang; Yifan Liu; Tomio Okawa
    Last, Applied Thermal Engineering, 228, 120518, 25 Jun. 2023, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Phenomenological modeling of quenching during falling liquid film cooling of high-temperature wall
    Yutaro Umehara; Tomio Okawa
    Last, Applied Thermal Engineering, 225, 120210, 05 May 2023, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Experimental study on the breakup of liquid jet discharged from a nozzle with sudden contraction
    Guofu Sun; Tomio Okawa; Mitsuhiro Aoyagi; Akihiro Uchibori; Yasushi Okano
    Proceedigns of 30th International Conference on Nuclear Engineering, ICONE30-1177, May 2023, Peer-reviwed
    International conference proceedings, English
  • Role of bubble coalescence in causing OSV in subcooled flow boiling
    Binh Thanh Nguyen; Ryoma Tsujimura; Tomio Okawa
    Last, Proceedigns of 30th International Conference on Nuclear Engineering, ICONE30-1054, May 2023, Peer-reviwed
    International conference proceedings, English
  • Early and late splashes during drop impact onto a quiescent liquid film
    Tomio Okawa; Katsuyuki Kawai; Kohei Kubo
    Lead, Proceedigns of 11th International Conference on Multiphase Flow, #772, Apr. 2023
    International conference proceedings, English
  • Numerical investigation on the effects of fundamental design parameters on freeze plug performance in molten salt reactors
    Muhammad Ilham; Indarta Kuncoro Aji; Tomio Okawa
    Last, Nuclear Engineering and Design, 403, 112144, Mar. 2023, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Validation of a Phenomenological Quenching Velocity Model in Extended Experimental Conditions
    Hiroyuki Umebayashi; Yutaro Umehara; Tomio Okawa
    Last, 12th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety, N12E1098, 02 Nov. 2022, False
    International conference proceedings, English
  • Improving Freeze Plug Performance in Molten Salt Reactors by Changing the Tube Inclination
    Muhammad Ilham; Tomio Okawa
    Last, 12th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety, N12E1082, 02 Nov. 2022, False
    International conference proceedings, English
  • Critical Heat Flux and Large Bubble Formation in Subcooled Flow Boiling
    Nguyen Thanh Binh, Ryoma Tsujimura, Tomio Okawa
    Last, 12th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety, N12E1113, 01 Nov. 2022, False
    International conference proceedings, English
  • Experiment on boiling entrainment from a falling liquid film
    T. Okawa, J. Tabuchi, R. Firman, Y. Narushima, H. Furuichi, and K. Katono
    Lead, 1st European-American-Japanese Two-Phase Flow Group Meeting, 25 Oct. 2022, Invited, True
    International conference proceedings, English
  • Quenching Heat Transfer Characteristics of Copper Rod in Saturated and Various Subcooled Condition
    H. Zeol; M. Z. Sulaiman; H. Z. Hui; H. Ismail; T. Okawa
    Last, Lecture Notes in Mechanical Engineering, 361-377, 09 Aug. 2022, Peer-reviwed
    International conference proceedings
    DOI URL
  • EXPERIMENT STUDY ON THE EFFECT OF NOZZLE SHAPE ON LIQUID JET BREAKUP
    Guofu Sun, Yi Zhan, Tomio Okawa, Mitsuhiro Aoyagi, Akihiro Uchibori, Yasushi Okano
    Proceedings of 29th International Conference on Nuclear Engineering, 7-B, ICONE29-93074-V07BT07A032, 08 Aug. 2022, Peer-reviwed, True
    International conference proceedings, English
    DOI URL
  • NUMERICAL ANALYSIS OF SIMPLE HEAT EQUATION TO PREDICT THE OPENING TIME OF THE FREEZE PLUG IN MOLTEN SALT REACTORS
    Muhammad Ilham; Tomio Okawa
    Last, Proceedings of 29th International Conference on Nuclear Engineering, 4, ICONE29-92284-V004T04A026, 08 Aug. 2022, Peer-reviwed, True
    International conference proceedings, English
    DOI URL
  • Experimental Study on Measurement of Boiling Entrainment Rate From Falling Liquid Film With Gas Sheared Flow
    B. P. Raka Firman; Junpei Tabuchi; Tomio Okawa; Yuki Narushima; Hajime Furuichi; Kenichi Katono
    Proceedings of 29th International Conference on Nuclear Engineering, 15, ICONE29-90420-V015T16A022, 08 Aug. 2022, Peer-reviwed, True
    International conference proceedings, English
    DOI URL
  • POSSIBLE ROLE OF BUBBLE COALESCENCE IN CAUSING OSV AND DNB IN SUBCOOLED FLOW BOILING
    Tomio Okawa; Nguyen Thanh Binh
    Lead, Japan-U.S. Seminar on Two-Phase Flow Dynamics, Keynote Lecture, 11 May 2022, Invited, True
    International conference proceedings, English
  • Developing a semi-mechanistic correlation for the onset of significant void in subcooled flow boiling
    Tomio Okawa
    Lead, International Communications in Heat and Mass Transfer, Elsevier, 134, 106047, May 2022, Peer-reviwed, True
    Scientific journal, English
    DOI URL
  • Spatial distribution of heat transfer coefficient in the vicinity of wetting front during falling liquid film cooling of a vertical hot wall
    Yutaro Umehara; Keisuke Yamagata; Tomio Okawa
    Last, International Journal of Heat and Mass Transfer, Elsevier, 185, 122422, 01 Apr. 2022, Peer-reviwed, True
    Scientific journal, English
    DOI URL
  • Heat Transfer Characteristics of Metallic Body during Quenching in Saturated Nanofluids
    H. Ismail; M. Z. Sulaiman; T. Okawa
    International Journal of Automotive and Mechanical Engineering, 19, 1, 9403-9411, 24 Mar. 2022, Peer-reviwed, True
    Scientific journal, English
    DOI URL
  • Effect of wall material on boiling heat transfer of nanofluid
    Tomio OKAWA, Koki NAKANO, Ren NING, Yutaro UMEHARA and Yasuo KOIZUMI
    Lead, 32nd International Symposium on Transport Phenomena, No.23, 20 Mar. 2022, Peer-reviwed, True
    International conference proceedings, English
  • VISUALIZATION STUDY FOR THE MECHANISMS TO CAUSE OSV AND DNB IN SUBCCOLED FLOW BOILING
    Tomio Okawa, Yuya Endo, and Ryoma Tsujimura
    Lead, 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19), Paper No. 36360, 09 Mar. 2022, Peer-reviwed, True
    International conference proceedings, English
  • EXPERIMENTS FOR THE MECHANISMS DETERMINING CHF AND HTC VALUES IN NANOFLUID POOL BOILING
    Ren Ning, Koki Nakano, Yutaro Umehara, Yasuo Koizumi, and Tomio Okawa
    19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19), Paper No. 36362, 09 Mar. 2022, Peer-reviwed, True
    International conference proceedings, English
  • PHENOMENOLOGICAL INTERPRETATION OF HEAT TRANSFER COEFFICIENT DISTRIBUTION NEAR THE REWETTING FRONT
    Yutaro Umehara; Tomio Okawa
    Last, 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19), Paper No. 34055, 09 Mar. 2022, Peer-reviwed, True
    International conference proceedings, English
  • EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF SPLASHING DURING SINGLE DROP IMPACT ONTO A LIQUID FILM
    Tomio Okawa, Katsuyuki Kawai, Kohei Kubo, Susumu Yamashita and Hiroyuki Yoshida
    Lead, 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19), Paper No. 34082, 08 Mar. 2022, Peer-reviwed, True
    International conference proceedings, English
  • Experimental observation of droplet entrainment by nucleate boiling in liquid film
    Yuki Narushima, Kenichi Katono, Junpei Tabuchi; Tomio Okawa
    Last, 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19), Paper No.34130, 07 Mar. 2022, Peer-reviwed, True
    International conference proceedings, English
  • Fundamental characteristics of secondary drops produced by early splash during single-drop impingement onto a thick liquid film
    Tomio Okawa; Katsuyuki Kawai; Kohei Kubo; Sota Kitabayashi
    Lead, Experimental Thermal and Fluid Science, Elsevier, 131, 110533, 01 Feb. 2022, Peer-reviwed, True
    Scientific journal, English
    DOI URL
  • Variations of nanoparticle layer properties during nucleate pool boiling
    Tomio Okawa; Koki Nakano; Yutaro Umehara
    Lead, Journal of Physics: Conference Series, Journal of Physics: Conference Series, 2116, 1, 012002, 08 Dec. 2021, Peer-reviwed, False
    International conference proceedings, English
    DOI URL
  • On the mechanism of onset of significant void in subcooled flow boiling
    Tomio Okawa
    International Journal of Heat and Mass Transfer, 181, Dec. 2021, Peer-reviwed, True
    Scientific journal, English
    DOI URL
  • Effect of Nanoparticle Layer Coating on Heat Transfer Performance of Heat Pipe
    Menglei Wang; Tomio Okawa
    Heat Transfer Engineering, 42, 19-20, 1748-1754, 13 Nov. 2021, Peer-reviwed, Invited, False
    Scientific journal, English
    DOI URL
  • A mechanistic modeling of OSV in subcooled flow boiling
    Tomio Okawa
    Proceedings of 2nd Asian Conference on Thermal Sciences, Paper No. 50221, 07 Oct. 2021, Peer-reviwed, False
    International conference proceedings, English
  • Improvements of thermal resistance and CHF by nanoparticle coating in heat pipes
    Menglei Wang, Tomio Okawa
    Proceedings of 2nd Asian Conference on Thermal Sciences, Paper No. 50611, 07 Oct. 2021, Peer-reviwed, False
    International conference proceedings, English
  • Microscopic heat transfer characteristics during cooling of high temperature surface by a falling liquid film
    Yutaro Umehara; Tomio Okawa
    International Conference on Nuclear Engineering, Proceedings, ICONE, 2, 04 Aug. 2021, Peer-reviwed, False
    International conference proceedings, English
    DOI URL
  • Numerical investigation of safety system parameters in molten salt reactor: Wall effect on freeze valve opening time
    Muhammad Ilham; Indarta Kuncoro Aji; Tomio Okawa
    International Conference on Nuclear Engineering, Proceedings, ICONE, 1, 04 Aug. 2021, Peer-reviwed, False
    International conference proceedings, English
    DOI URL
  • Droplet generation during spray impact onto a downward-facing solid surface
    Yi Zhan; Guofu Sun; Tomio Okawa; Mitsuhiro Aoyagi; Takashi Takata
    Experimental Thermal and Fluid Science, Elsevier, 126, 110402, 01 Aug. 2021, Peer-reviwed, True
    Scientific journal, English
    DOI URL
  • Role of nanoparticle layer in determining minimum heat flux temperature during quenching of high-temperature body
    Yutaro UMEHARA, Tomio OKAWA
    Mechanical Engineering Journal, JAPAN SOC MECHANICAL ENGINEERS, 20, 00527, 18 Mar. 2021, Peer-reviwed, False
    Scientific journal, English
  • Experimental Investigation of the Deformation of Gas-Liquid Two-Phase Jet
    Guofu Sun, Yi Zhan, Takuji Kobayashi, Tomio Okawa, Motoki Irikura
    Japanese Journal of Multiphase Flow, 35, 1, 77-84, 15 Mar. 2021, Peer-reviwed, False
    Scientific journal, Japanese
  • Experiments on splashing thresholds during single-drop impact onto a quiescent liquid film
    Tomio Okawa; Kohei Kubo; Katsuyuki Kawai; Sota Kitabayashi
    Experimental Thermal and Fluid Science, 121, 01 Feb. 2021, Invited, True
    Scientific journal, English
    DOI URL
  • Experimental observation of nucleate boiling entrainment in a liquid film
    Junpei Tabuchi; Yuki Narushima; Kenichi Katono; Tomio Okawa
    International Conference on Nuclear Engineering, Proceedings, ICONE, 4, 2021
    International conference proceedings
    DOI URL
  • Fundamentals for power engineering
    Tomio Okawa; Hitoshi Asano; Kei Ito; Shoji Mori; Hisashi Umekawa; Ryosuke Matsumoto; Cheol Ho Pyeon; Daisuke Ito
    Fundamentals of Thermal and Nuclear Power Generation, 77-226, 01 Jan. 2021
    In book
    DOI URL
  • Experimental study on secondary droplets produced during liquid jet impingement onto a horizon solid surface
    Yi Zhan, Yusuke Kuwata, Tomio Okawa, Mitsuhiro Aoyagi, Takashi Takata
    Experimental Thermal and Fluid Science, Elsevier, 120, 110249, 01 Jan. 2021, Peer-reviwed, True
    Scientific journal, English
    DOI URL
  • Study on melting process of solid salt contained in metal vessel
    Tomio Okawa, Tatsuya Tokushima, Indarta Kuncoro Aji, and Mahammad Ilham
    Advances in Thermal Hydraulics (ATH '20), 308-319, 20 Oct. 2020, Peer-reviwed, True
    International conference proceedings, English
  • Special section: Selected papers from ICONE-27
    Jovica Riznic; Tomio Okawa; Asif Arastu; Leon Cizelj; Shripad Revankar; Richard Schultz
    Journal of Nuclear Engineering and Radiation Science, 6, 4, 01 Oct. 2020
    Scientific journal
    DOI URL
  • Two-phase flow regimes of refrigerant R134a in an oscillating horizontal rectangular minichannel conduit
    Koji Enoki, Masaharu Ono, Tomio Okawa, Atsushi Akisawa, Budi Kristiawan, Agung Tri Wijayanta
    International Journal of Refrigeration, Elsevier, 118, 261-268, 01 Oct. 2020, Peer-reviwed, True
    Scientific journal, English
    DOI URL
  • Photographic Study on the Onset of Significant Void in Water Subcooled Flow Boiling at Low Pressure
    Tomio Okawa, Yuya Endo, Hongji Li, and Hideki Takahashi
    3rd International E-Conference on Advances in Engineering Technology and Management (ICETM 2020), ICETM-20-116, 27 Sep. 2020, Peer-reviwed, False
    International conference proceedings, English
  • Water flow boiling heat transfer in vertical minichannel
    Koji Enoki, Masaharu Ono, Tomio Okawa, Budi Kristiawan, Agung Tri Wijayanta
    Experimental Thermal and Fluid Science, Elsevier, 117, 110147, 01 Sep. 2020, Peer-reviwed, True
    Scientific journal, English
    DOI URL
  • Prediction of Extremely High Minimum Heat Flux Point During Quenching in Nanofluid
    Yutaro Umehara, Tomio Okawa
    ASME Nuclear Engineering Conference powered by ICONE, Paper No: ICONE2020-16032, 03 Aug. 2020, Peer-reviwed, True
    International conference proceedings, English
  • Measurement of heat transfer coefficient profile during quenching of a vertical hot wall with a falling liquid film
    Tomio Okawa, Keisuke Yamagata, Yutaro Umehara
    Nuclear Engineering and Design, Elsevier, 363, 110629, 01 Jul. 2020, Peer-reviwed, Invited, True
    Scientific journal, English
    DOI URL
  • Quasi steady state of nucleate boiling heat transfer in low concentration of single and hybrid Al2O3-SiO2 water-based nanofluids
    M. A.H. Aizzat; M. Z. Sulaiman; T. Okawa
    IOP Conference Series: Materials Science and Engineering, 788, 1, 05 Jun. 2020
    International conference proceedings
    DOI URL
  • Effects of surface tension and viscosity on liquid jet breakup
    Yi Zhan, Yusuke Kuwata, Kiyotaka Maruyama, Tomio Okawa, Koji Enoki, Mitsuhiro Aoyagi, Takashi Takata
    Experimental Thermal and Fluid Science, Elsevier, 112, 109953, 01 Apr. 2020, Peer-reviwed, True
    Scientific journal, English
    DOI URL
  • 気水分離器における液滴キャリーオーバーに関する研究（気液二相噴流の分裂開始長さに関する実験的検討）
    詹翼、孫国富、大川富雄、入倉基樹
    混相流, 日本混相流学会, 34, 1, 75-81, 15 Mar. 2020, Peer-reviwed, Invited, False
    Scientific journal, Japanese
  • 焼結製法による高気孔率金属繊維多孔質伝熱面におけるサブクール沸騰熱伝達による高熱流束除熱
    KUMATORI Kousuke; OTOMO Yusuke; SANTIAGO-GALICIA Edgar; OKAWA Tomio; ORITO Kenji; TAKITA Kenji; SAIWAI Toshihiko; ENOKI Koji
    JAPANESE JOURNAL OF MULTIPHASE FLOW, THE JAPANESE SOCIETY FOR MULTIPHASE FLOW, 34, 1, 64-74, 15 Mar. 2020, Peer-reviwed, False, Nowadays high performance cooling equipment are required for high heat dissipation electric devices. In this research, the experiments were carried out with high porosity sintered fiber on the surface under the forced convection subcooled boiling heat transfer. The experimental parameter of the porous is the filling height relative to the channel height, and the porosity of porous material was 86 %. According to the experiments, all of porous surfaces, almost 2 times higher performance on boiling heat transfer compared with the bare surface under the same wall superheat ⊿Tsat (K) conditions. However, the high height porous condition, the CHF tend to low compared with lower height porous condition and bare surface. In addition, the relations between the bubble behavior and the heat transfer were analyzed from experimental results and the videos acquired by high speed camera.
    Scientific journal, Japanese
    URL
    URL 2
    DOI URL
  • Measurement of Capillary Wicking Height for the Packed Bed of Nanoparticles
    Tomio Okawa and Yutaro Umehara
    International Conference on Engineering & Technology (ICET-20), 53-56, 28 Feb. 2020, Peer-reviwed, False
    International conference proceedings, English
  • Greetings from JSME and the report on ICone27
    Tomio Okawa
    Journal of Nuclear Engineering and Radiation Science, 6, 1, 2020
    Scientific journal
    DOI URL
  • An experimental and numerical study of wall effect on freeze valve performance in a molten salt reactor
    Indarta Kuncoro Aji, Tatsuya Tatsuya, Motoyasu Kinoshita, Tomio Okawa
    Journal of Nuclear Engineering and Radiation Science, ASME, 6, 2, 21105, 2020, Peer-reviwed, True
    Scientific journal, English
    DOI URL
  • Convection effect of the freeze valve melting process on molten salt reactor
    Indarta Kuncoro Aji; Tatsuya Tokushima; Koji Enoki; Motoyasu Kinoshita; Tomio Okawa
    International Conference on Nuclear Engineering, Proceedings, ICONE, 2019-May, 18 May 2019
    International conference proceedings
  • Experimental study on splash ratio and size of secondary droplets during liquid jet collision onto a solid surface
    Yi Zhan; Yusuke Kuwata; Kiyotaka Maruyama; Koji Enoki; Tomio Okawa; Mitsuhiro Aoyagi; Takashi Takata
    International Conference on Nuclear Engineering, Proceedings, ICONE, 2019-May, 18 May 2019
    International conference proceedings
  • An experimental study of the freeze valve opening time with considering wall effect
    Tatsuya Tokushima; Indarta Kuncoro Aji; Koji Enoki; Motoyasu Kinoshita; Tomio Okawa
    International Conference on Nuclear Engineering, Proceedings, ICONE, 2019-May, 18 May 2019
    International conference proceedings
  • Temperature distribution measurement during quenching of high-temperature wall with a falling liquid film
    Tomio Okawa; Keisuke Yamagata; Koji Enoki
    18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019, 300-306, 2019
    International conference proceedings
  • Experiments on Lift-off Bubble Size Distribution in Subcooled Flow Boiling
    OKAWA Tomio; KAIHO Kazuhiro; LI Hongji; OHORI Koki; SAKAMOTO Shintaro; ENOKI Koji
    The Proceedings of the National Symposium on Power and Energy Systems, The Japan Society of Mechanical Engineers, 2019.24, A215, 2019, Bubble size is an important fundamental parameter in subcooled flow boiling. In this study, bubble behavior in subcooled flow boiling was visualized to confirm that mean bubble size is considerably different between different nucleation sites. Empirical correlations were developed using the present experimental data for the distribution of mean bubble size and the distribution of the size of bubbles produced in each site. Observation of the nucleation sites using a microscope revealed that tower-shaped structure is present at the nucleation sites where small bubbles are produced whilst no such structure was found at the sites where large bubbles are produced. This result suggest that bubble size is dependent significantly on the nucleation site geometry.
    Japanese
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    DOI URL
  • Evaluation of the Performance of Nanofluid as Quenching Coolant
    Umehara Yutaro; Okawa Tomio; Enoki Koji
    Tetsu-to-Hagane, The Iron and Steel Institute of Japan, 105, 11, 1050-1058, 2019, Nanofluid is a liquid in which nanometer-sized particles are dispersed in base liquid. It is known that the critical heat flux and the wall superheat at the minimum heat flux in pool boiling are improved in nanofluids. In this research, performance of silica-water nanofluid as quenching coolant is explored experimentally since the above-mentioned parameters play important roles in this application. First, we investigated the immersion cooling of high-temperature test piece in the nanofluid; here, the test piece was cylindrical in shape and made of Inconel 718 or SUS304. It was confirmed that the test piece is cooled faster in the nanofluid than in distilled water. It was also found that non-uniformity of temperature in the test piece during quenching is mitigated in the nanofluid. This indicates that the silica nanofluid is considered a promising coolant to avoid the occurrence of hardening crack during quenching. Finally, Vickers hardness test was done for the Inconel 718 test piece. It was shown that the hardness tends to increase with an increase in the cooling rate even under the high cooling rate of about 1000 K/min although the difference of hardness was not noticeable between the experiments using the distilled water and the silica nanofluid as the quenching coolant.
    Japanese
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    URL 2
    DOI URL
    DOI 2 URL
  • Droplet generation during liquid jet impingement onto a horizontal plate
    Yi Zhan; Naoki Oya; Koji Enoki; Tomio Okawa; Mitsuhiro Aoyagi; Takashi Takata
    Experimental Thermal and Fluid Science, 98, 86-94, Nov. 2018
    Scientific journal
    DOI URL
  • Droplet generation during liquid jet impingement onto a horizontal plate
    Yi Zhan; Naoki Oya; Koji Enoki; Tomio Okawa; Mitsuhiro Aoyagi; Takashi Takata
    EXPERIMENTAL THERMAL AND FLUID SCIENCE, 98, 86-94, Nov. 2018
    Scientific journal, English
    DOI URL
  • Heat transfer coefficient of nucleate boiling in low concentration level of single and hybrid Al2O3-SiO2 water-based nanofluids
    M A H Aizzat; Muhamad Zuhairi Sulaiman; Koji Enoki; Tomio Okawa
    AIP Conference Proceedings, Materials Science and Engineering, 469, 1, 012109, Oct. 2018, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Nanoparticle layer detachment and its influence on the heat transfer characteristics in saturated pool boiling of nanofluids
    Yosuke Watanabe; Koji Enoki; Tomio Okawa
    International Journal of Heat and Mass Transfer, Elsevier BV, 125, 171-178, Oct. 2018
    DOI URL
    DOI 2 URL
  • Nanoparticle layer detachment and its influence on the heat transfer characteristics in saturated pool boiling of nanofluids
    Yosuke Watanabe; Koji Enoki; Tomio Okawa
    International Journal of Heat and Mass Transfer, 125, 171-178, Oct. 2018
    Scientific journal
    DOI URL
  • Nanoparticle layer detachment and its influence on the heat transfer characteristics in saturated pool boiling of nanofluids
    Yosuke Watanabe; Koji Enoki; Tomio Okawa
    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 125, 171-178, Oct. 2018
    Scientific journal, English
    DOI URL
  • Observation and modelling of bubble dynamics in isolated bubble regime in subcooled flow boiling
    Tomio Okawa; Kazuhiro Kaiho; Shintaro Sakamoto; Koji Enoki
    Nuclear Engineering and Design, 335, 400-408, 15 Aug. 2018
    Scientific journal
    DOI URL
  • Observation and modelling of bubble dynamics in isolated bubble regime in subcooled flow boiling
    Tomio Okawa; Kazuhiro Kaiho; Shintaro Sakamoto; Koji Enoki
    NUCLEAR ENGINEERING AND DESIGN, 335, 400-408, Aug. 2018
    Scientific journal, English
    DOI URL
  • An experimental study on freeze valve performance in a molten salt reactor
    Indarta Kuncoro Aji; Motoyasu Kinoshita; Tokushima Tatsuya; Tomio Okawa
    International Conference on Nuclear Engineering, Proceedings, ICONE, American Society of Mechanical Engineers (ASME), 9, 2018
    International conference proceedings, English
    DOI URL
  • Modeling of bubble behavior in low void fraction subcooled flow boiling
    Shintaro Sakamoto; Koji Enoki; Hiroki Ohori; Tomio Okawa
    International Conference on Nuclear Engineering, Proceedings, ICONE, 9, 2018
    International conference proceedings
    DOI URL
  • MODELING OF BUBBLE BEHAVIOR IN LOW VOID FRACTION SUBCOOLED FLOW BOILING
    Shintaro Sakamoto; Hiroki Ohori; Koji Enoki; Tomio Okawa
    PROCEEDINGS OF THE 26TH INTERNATIONAL CONFERENCE ON NUCLEAR ENGINEERING, 2018, VOL 9, 2018
    International conference proceedings, English
  • Direct Measurement of Heat Transfer Coefficient Distribution around the Rewetting Front during High Temperature Surface Liquid Cooling
    Yamagata Keisuke; Enoki Koji; Okawa Tomio
    The Proceedings of the Thermal Engineering Conference, The Japan Society of Mechanical Engineers, 2018, 0039, 2018, In order to elucidate the rewetting phenomenon in detail, it is important to know the distribution of the heat transfer coefficient in the vicinity of the rewetting front. However, the distribution of the heat transfer coefficient is not yet known in detail, and there are few data that directly measured its distribution. In this study, the temperature distribution of the wall surface temperature when the liquid film flows down was measured using a high-speed infrared camera, and the distribution of heat transfer coefficient was directly measured from the temperature data. We tried to experimentally determine the dominant factors influencing the heat transfer coefficient by changing experiment parameters.
    Japanese
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    DOI URL
  • Effect of Various Parameters on Boiling Heat Transfer of Nanofluids
    Watanabe Yosuke; Enoki Koji; Okawa Tomio
    The Proceedings of the Thermal Engineering Conference, The Japan Society of Mechanical Engineers, 2018, 0037, 2018, In nucleate boiling of nanofluids, heat transfer coefficient and CHF change due to nanoparticle layer formation on the heated surface. It is considered that the nanoparticle layer causes the changes of wettability and roughness of the heated surface. In this study, influences of the total mass of nanoparticle layer and properties of the heated surface were experimentally investigated parametrically changing the nanoparticle concentration and the heat flux during nanoparticle layer formation. The heated surface material was copper and the material of nanoparticles was titanium-dioxide, alumina, and silica. The influencing parameter for the total mass of the nanoparticle layer was elucidated experimentally.
    Japanese
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    DOI URL
  • Study on Thermal Performance of Nanofluid in Heat Pipe
    Menglei Wang; Enoki Koji; Okawa Tomio
    The Proceedings of the Thermal Engineering Conference, The Japan Society of Mechanical Engineers, 2018, 0029, 2018, In this research, silicon dioxide/DI water nanofluid was used as the working fluid in a cylindrical heat pipe to experimentally investigate its effect to enhance the heat transfer performance. In the experiment, the one end of the heat pipe was heated using a nichrome wire heater and the other end was cooled using a fan. In addition, effects of pre-coating of the screen mesh and the inside wall of the heat pipe with nanoparticles on heat transfer performance were explored. The experimental results showed that in comparison with the normal heat pipe BBW (bare tube / bare mesh / pure water), the thermal resistance of BNW (bare tube / nanoparticle-coated mesh / pure water) is reduced by 2-8% for the input power of 3-9W. When the power was increased to 9-25W, however, the thermal resistances of NXW (nanoparticle-coated tube / no mesh / pure water) and NBW (nanoparticle-coated tube / bare mesh / pure water) decreased 13-32%. This corresponded to the heat transfer enhancement of 15-40%.
    Japanese
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    DOI URL
  • Elucidation of Flow Distribution of Two-phase Flow in the Parallel Mini-channel Evaporator
    ONO Masahaharu; ENOKI Koji; KANJA Keisuke; NAKAMURA Taichi; OKAWA Tomio; NISHIDA Kosaku; KATO Masashi
    Transactions of the Japan Society of Refrigerating and Air Conditioning Engineers, Japan Society of Refrigerating and Air Conditioning Engineers, 34, 4, 413, 31 Dec. 2017, In this study, the experiments were performed to observe vertically upward vapor-liquid two-phase flow of HFE-7000 in the parallel microchannel whose hydraulic diameter was 0.93 mm per a path by using a high-speed camera. The experiments were conducted by heating the microchannel portion for use as evaporator. The saturation temperature was 30 °C. In order to investigate the influence of the inlet qualities of the test section on the flow pattern, the experiments were conducted to keep exit quality at xout = 0.9 and mass flow rate W = 0.0022 kg･s-1, set inlet qualities at xin = 0, 0.2 0.7. From the results of the observation, it was clear that the cause of drift flow was unevenness of the vapor and liquid distribution in the inlet header. Moreover, back flow which is thought to degrade the heat exchanger performance was observed as well, and it was found that the cause was rapid expansion of the vapor plug. Therefore, when the inlet header part was made a modified shape narrowing the flow path area as it goes away from the test section inlet part, drift flow and back flow were suppressed. Furthermore, in order to investigate the influence on the heat exchanging performance by drift flow and back flow, the downstream side of the test section was photographed and measured using an IR camera. In the case of a vapor-liquid mal-distribution in the inlet header section, temperature rise accompanying dryout had been constantly occurring on the downstream side in the flow path near the test section inlet. However, in the case of the modified inlet header shape, it was found that the mal-distribution of the heat distribution on the downstream side due to the drift was reduced.
    Japanese
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    DOI URL
  • Measurement of the maximum bubble size distribution in water subcooled flow boiling at low pressure
    Kazuhiro Kaiho; Tomio Okawa; Koji Enoki
    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 108, 2365-2380, May 2017, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Quench characteristics of high temperature objects in nanofluids
    UMEHARA Yutaro; ENOKI Koji; OKAWA Tomio; OGATA Takashi
    The Proceedings of Conference of Kanto Branch, The Japan Society of Mechanical Engineers, 2017.23, 406, 2017
    Japanese
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    DOI URL
  • Experiments on the splashing limit during drop impact onto a thin liquid film
    Sota Kitabayashi; Koji Enoki; Tomio Okawa
    International Conference on Nuclear Engineering, Proceedings, ICONE, 9, 2017
    International conference proceedings
    DOI URL
  • Splash during liquid jet impingement onto a horizontal plate
    Yi Zhan; Naoki Oya; Koji Enoki; Tomio Okawa; Shuji Ohno; Mitsuhiro Aoyagi; Takashi Takata
    International Conference on Nuclear Engineering, Proceedings, ICONE, 9, 2017
    International conference proceedings
    DOI URL
  • Characteristics of bubbles produced at nucleation sites in subcooled flow boiling
    Tomio Okawa; Kazuhiro Kaiho; Shintaro Sakamoto; Koji Enoki
    17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2017, 2017-September, 2017
    International conference proceedings
  • Peeling of nanoparticle layer on a heated surface and its influence on pool boiling CHF
    Tomio Okawa; Yosuke Watanabe; Koji Enoki
    17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2017, 2017-September, 2017
    International conference proceedings
  • The Characteristics of Vapor-liquid Two-phase Flow in Mini-Channels
    NAKAMURA Taichi; ONO Masaharu; ENOKI Koji; OKAWA Tomio; KATO Masashi; NISHIDA Kousaku
    The Proceedings of Conference of Kanto Branch, The Japan Society of Mechanical Engineers, 2017.23, 413, 2017
    Japanese
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    DOI URL
  • Bubble lift-off conditions on numerical analysis of subcooled flow boiling
    SAKAMOTO Shintaro; KAIHO Kazuhiro; ENOKI Koji; OKAWA Tomio
    The Proceedings of Conference of Kanto Branch, The Japan Society of Mechanical Engineers, 2017.23, 501, 2017
    Japanese
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    DOI URL
  • EXPERIMENTS ON THE SPLASHING LIMIT DURING DROP IMPACT ONTO A THIN LIQUID FILM
    Sota Kitabayashi; Koji Enoki; Tomio Okawa
    PROCEEDINGS OF THE 25TH INTERNATIONAL CONFERENCE ON NUCLEAR ENGINEERING, 2017, VOL 9, 2017
    International conference proceedings, English
  • SPLASH DURING LIQUID JET IMPINGEMENT ONTO A HORIZONTAL PLATE
    Yi Zhan; Naoki Oya; Koji Enoki; Tomio Okawa; Shuji Ohno; Mitsuhiro Aoyagi; Takashi Takata
    PROCEEDINGS OF THE 25TH INTERNATIONAL CONFERENCE ON NUCLEAR ENGINEERING, 2017, VOL 9, 2017
    International conference proceedings, English
  • Relationship with heat flux and noise and pressure fluctuation in porous-micro-channel
    HIRATA Ryo; OHASHI Junki; ENOKI Koji; OKAWA Tomio
    The Proceedings of Conference of Kanto Branch, The Japan Society of Mechanical Engineers, 2017.23, 410, 2017
    Japanese
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    DOI URL
  • The detachment of nanoparticle layer on boiling heat-transfer of nanofluids
    WATANABE Yosuke; ENOKI Koji; OKAWA Tomio
    The Proceedings of Conference of Kanto Branch, The Japan Society of Mechanical Engineers, 2017.23, 405, 2017
    Japanese
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    DOI URL
  • A study on secondary droplet production during drop impingement onto a thin liquid film
    KITABAYASHI Sota; ENOKI Koji; OKAWA Tomio
    The Proceedings of Conference of Kanto Branch, The Japan Society of Mechanical Engineers, 2017.23, 302, 2017
    Japanese
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    DOI URL
  • Systematic measurements of heat transfer characteristics in saturated pool boiling of water-based nanofluids
    Muhamad Zuhairi Sulaiman; Daisuke Matsuo; Koji Enoki; Tomio Okawa
    International Journal of Heat and Mass Transfer, Elsevier BV, 102, 264-276, Nov. 2016
    URL
    DOI URL
  • Systematic measurements of heat transfer characteristics in saturated pool boiling of water-based nanofluids
    Muhamad Zuhairi Sulaiman; Daisuke Matsuo; Koji Enoki; Tomio Okawa
    International Journal of Heat and Mass Transfer, 102, 264-276, 01 Nov. 2016
    Scientific journal
    DOI URL
  • Systematic measurements of heat transfer characteristics in saturated pool boiling of water-based nanofluids
    Muhamad Zuhairi Sulaiman; Daisuke Matsuo; Koji Enoki; Tomio Okawa
    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 102, 264-276, Nov. 2016
    Scientific journal, English
    DOI URL
  • Accurate estimation of vaporization rate in subcooled flow boiling based on the results of visualization experiment
    Kazuhiro Kaiho; Koji Enoki; Tomio Okawa
    International Conference on Nuclear Engineering, Proceedings, ICONE, 5, 2016
    International conference proceedings
    DOI URL
  • Experimental study on splashing during liquid jet impingement onto a liquid film
    Zhan Yi; Naoki Oya; Koji Enoki; Tomio Okawa; Shuji Ohno; Mitsuhiro Aoyagi
    International Conference on Nuclear Engineering, Proceedings, ICONE, 5, 2016
    International conference proceedings
    DOI URL
  • Vapor - liquid Two - phase Flow Patterns and the Effects of Oscillation of a Refrigerant Flowing in Small Horizontal Rectangular Tube
    OHNO Masaharu; ENOKI Koji; NAGAYAMA Kunihiro; AKISAWA Atsushi; Okawa Tomio; MIYATA Kazushi; MORI Hideo
    The Proceedings of the National Symposium on Power and Energy Systems, The Japan Society of Mechanical Engineers, 2016.21, A212, 2016, In this study, we performed to observe horizontal vapor-liquid two phase flow of refrigerant R 134a in the rectangular glass channel which hydraulic diameter is 0.84 mm. The test glass tube was added the oscillation to the gravity direction for slug and stratified flow under low mass flux and heat flux. When the channel was oscillated of certain frequency and amplitude, the liquid of the corner part of rectangular channel waved up and down. In slug flow, dry surface of central was supplied the liquid by the oscillation and was formed the thin liquid. In stratified flow, dry surface of top was supplied the liquid and flow pattern changed to annular from stratified flow. The oscillation influences were investigated in a quantitative way.
    Japanese
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  • Effects of bubble lift-off conditions on numerical analysis of subcooled flow boiling
    Sakamoto Shintaro; Kaiho Kazuhiro; Enoki Koji; Okawa Tomio
    The Proceedings of the Thermal Engineering Conference, The Japan Society of Mechanical Engineers, 2016, C221, 2016, Numerical simulation of subcooled flow boiling in a vertical rectangular duct was carried out using a one-way bubble tracking method; this method treats each bubble as an individual particle. Although a bubble behavior after lifting off the heated surface depends on the bubble size and velocity at lift-off, these lift-off conditions are not taken into consideration in existing subcooled flow boiling models. In the present simulation, the distributions of lift-off velocity and bubble size were considered. It was demonstrated that the calculated void fraction in subcooled flow boiling is influenced significantly by the lift-off conditions.
    Japanese
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  • High-Heat-Flux Heat Removal Using A Porous-Micro-Channel
    OHASHI Junki; TSUKAMOTO Akihiro; ENOKI Koji; OKAWA Tomio
    The Proceedings of the National Symposium on Power and Energy Systems, The Japan Society of Mechanical Engineers, 2016.21, A223, 2016, Experiments were carried out to investigate the characteristics of high-heat-flux heat removal using a porous-micro-channel (a small rectangular channel filled with a porous-metal plate). The working fluid was water and the main experimental parameters were the inlet liquid subcooling, mass flux, and channel size. It was shown that nucleate boiling heat transfer is enhanced in the porous-micro-channel in comparison with the normal rectangular channel. Another important finding was that as in the normal channel, the micro-bubble emission boiling (MEB) occurs in the porous-micro-channel if the mass flux and liquid subcooling are high enough. In addition, the flow oscillation and noise production that often accompany with the MEB in the normal channel were mitigated significantly in the porous-micro-channel. This indicates that the porous-micro-channel enables the stable and high-heat-flux heat removal by the MEB.
    Japanese
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  • ACCURATE ESTIMATION OF VAPORIZATION RATE IN SUBCOOLED FLOW BOILING BASED ON THE RESULTS OF VISUALIZATION EXPERIMENT
    Kazuhiro Kaiho; Koji Enoki; Tomio Okawa
    PROCEEDINGS OF THE 24TH INTERNATIONAL CONFERENCE ON NUCLEAR ENGINEERING, 2016, VOL 5, 2016
    International conference proceedings, English
  • Measurements of pressure fluctuation and sound production in flow boiling in a porous-micro-channel
    Ohashi Junki; Hirata Ryo; Enoki Koji; Okawa Tomio
    The Proceedings of the Thermal Engineering Conference, The Japan Society of Mechanical Engineers, 2016, I112, 2016, Experiments were carried out to investigate the characteristics of high-heat-flux heat removal using a porousmicro-channel under the condition of high liquid subcooling and high mass flux. The working fluid was water and the main experimental parameters were insertion of porous plate and channel size. It was shown that fluctuation of heating surface temperature and flow oscillation are mitigated if the porous plate is placed in the flow channel. Another finding was that the sound production in the flow channel under the high heat flux condition is also mitigated in the porous-micro-channel. These results indicate that the porous-micro-channel is advantageous for the high-heat-flux heat removal from high-power-density devices.
    Japanese
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  • An experimental study on the secondary droplets production during the drop impingement onto a thin liquid film
    Kitabayashi Sota; Enoki Koji; Okawa Tomio
    The Proceedings of the Thermal Engineering Conference, The Japan Society of Mechanical Engineers, 2016, C135, 2016, The secondary droplets production during the drop impingement onto a liquid film has been studied extensively by many researchers. It is known that the two types of splashing mechanisms are present: the prompt splash and the late splash. In the prompt splash, small droplets are scattered with high velocity immediately after the impact. Whilst, in the late splash, larger droplets of lower velocity are produced after the development of liquid crown. In the present experiments, the empirical correlations of splashing limit for pure water are proposed separately for the prompt and late splashes. Since the splashing limit was dependent on the impact velocity and liquid film thickness, the two dimensionless numbers (the Weber number and the dimensionless film thickness) were used in the correlations.
    Japanese
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  • An experimental study on the secondary droplets production during the drop impingement onto a liquid film
    ENOKI Koji; Matsuse Kohei; Okawa Tomio
    The Proceedings of the National Symposium on Power and Energy Systems, The Japan Society of Mechanical Engineers, 2016.21, A213, 2016, Experiments were performed to explore the conditions for the onset of secondary droplet formation during single drop impact onto a liquid film(splashing). It was found that there were two types of splashing: the prompt splash and the late splash. In the prompt splash, small droplets were scattered with high velocity immediately after the impact. Whilst, in the late splash, larger droplets of lower velocity were produced after the development of liquid crown. The condition for the onset of splashing was expressed using the two dimensionless numbers: the Weber number, the Ohnesorge number. The correlations were given separately for the prompt and late splashes. Moreover new correlations were developed about prediction of the secondary droplet diameter and velocity.
    Japanese
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  • NUMERICAL SIMULATION OF SUBCOOLED FLOW BOILING USING A BUBBLE TRACKING METHOD
    Tomio Okawa; Naoki Miyano; Kazuhiro Kaiho; Koji Enoki
    PROCEEDINGS OF THE 24TH INTERNATIONAL CONFERENCE ON NUCLEAR ENGINEERING, 2016, VOL 3, 2016, Peer-reviwed
    International conference proceedings, English
  • Influence of surface wettability on bubble behavior and void evolution in subcooled flow boiling
    Rouhollah Ahmadi; Tomio Okawa
    INTERNATIONAL JOURNAL OF THERMAL SCIENCES, 97, 114-125, Nov. 2015, Peer-reviwed
    Scientific journal, English
    DOI URL
  • B213 Visualization Analysis of the Boiling Characteristics during the Water Subcooled Flow Boiling in Low Pressure
    Kaiho Kazuhiro; Tuchie Kenta; Miyano Naoki; Enoki Koji; Okawa Tomio
    The Proceedings of the Thermal Engineering Conference, The Japan Society of Mechanical Engineers, 2015, _B213-1_-_B213-2_, 2015, In the subcooled flow boiling, bubble size is important in calculating the vaporization rate accurately. On the surface, a number of bubbles that are different size are generated. If the bubble size is assumed to be uniform, a serious error may be caused in the numerical simulation. In this study, considering bubble size distribution, the bubble size are predicted by the gamma distribution. It was demonstrated that the gamma distribution satisfactorily describes the bubble distribution data. Furthermore, correlations were developed for the dimensionless bubble size and shape parameter to enable accurate prediction of them in the subcooled flow boiling.
    Japanese
    URL
    DOI URL
  • Visualization study on the mechanisms of net vapor generation in water subcooled flow boiling under moderate pressure conditions
    Rouhollah Ahmadi; Tatsuya Ueno; Tomio Okawa
    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 70, 137-151, Mar. 2014, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Experimental identification of the phenomenon triggering the net vapor generation in upward subcooled flow boiling of water at low pressure
    Rouhollah Ahmadi; Tatsuya Ueno; Tomio Okawa
    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 55, 21-22, 6067-6076, Oct. 2012, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Boiling time effect on CHF enhancement in pool boiling of nanofluids
    Tomio Okawa; Masahiro Takamura; Takahito Kamiya
    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 55, 9-10, 2719-2725, Apr. 2012, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Boiling heat transfer and critical heat flux enhancement of upward- and downward-facing heater in nanofluids
    Muhamad Zuhairi Sulaiman; Masahiro Takamura; Kazuki Nakahashi; Tomio Okawa
    International Conference on Nuclear Engineering, Proceedings, ICONE, American Society of Mechanical Engineers (ASME), 5, 1, 451-458, 2012, Peer-reviwed
    International conference proceedings, English
    DOI URL
  • Influence of a flow obstacle on boiling two-phase flow
    Takeyuki Ami; Hisashi Umekawa; Mamoru Ozawa; Tomio Okawa
    Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 78, 788, 894-904, 2012, Peer-reviwed
    Scientific journal, Japanese
    DOI URL
  • Onset of nucleate boiling in mini and microchannels: A brief review
    Tomio Okawa
    Frontiers in Heat and Mass Transfer, 3, 1, 2012, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Boiling heat transfer during single nanofluid drop impacts onto a hot wall
    Tomio Okawa; Kenta Nagano; Takahiro Hirano
    Experimental Thermal and Fluid Science, 36, 78-85, Jan. 2012, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Bubble dynamics at boiling incipience in subcooled upward flow boiling
    Rouhollah Ahmadi; Tatsuya Ueno; Tomio Okawa
    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 55, 1-3, 488-497, Jan. 2012, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Rate of droplet deposition in steam-water annular flow and effect of a flow obstacle
    Tomio Okawa; Toshihiro Murakami; Rei Takei
    NUCLEAR ENGINEERING AND DESIGN, 241, 11, 4497-4503, Nov. 2011, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Dependence of bubble behavior in subcooled boiling on surface wettability
    Takahiro Harada; Hiroshi Nagakura; Tomio Okawa
    NUCLEAR ENGINEERING AND DESIGN, 240, 12, 3949-3955, Dec. 2010, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Numerical verification of a simplified model for vapor bubble lift-off from a hydrophilic heated flat-wall
    Tomio Okawa; Kosuke Hayashi; Akio Tomiyama
    NUCLEAR ENGINEERING AND DESIGN, 240, 12, 3942-3948, Dec. 2010, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Photographic Study on Bubble Motion in Subcooled Pool Boiling
    Tomio Okawa; Takahiro Harada; Yuta Kotsusa
    JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME, 132, 10, Oct. 2010, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Numerical Study of Particle Concentration Effect on Deposition Characteristics in Turbulent Pipe Flows
    Yasushi Yamamoto; Tomio Okawa
    JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 47, 10, 945-952, Oct. 2010, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Liquid film behavior in annular two-phase flow under flow oscillation conditions
    Tomio Okawa; Taisuke Goto; Yosuke Yamagoe
    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 53, 5-6, 962-971, Feb. 2010, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Experimental studies on pool boiling characteristics of titanium dioxide-water nano-fluids
    Tomio Okawa; Takahito Kamiya
    International Conference on Nuclear Engineering, Proceedings, ICONE, 4, 1085-1089, 2010, Peer-reviwed
    International conference proceedings, English
    DOI URL
  • Liquid film dryout in a boiling channel under flow oscillation conditions
    Tomio Okawa; Taisuke Goto; Jun Minamitani; Yosuke Yamagoe
    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 52, 15-16, 3665-3675, Jul. 2009, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Effects of Particle Relaxation Time and Continuous-Phase Reynolds Number on Particle Deposition in Vertical Turbulent Pipe Flows
    Yasushi Yamamoto; Tomio Okawa
    JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 46, 4, 382-391, Apr. 2009, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Analytical Study on Boiling Transition under Flow-Power Oscillating Condition for Hyper ABWR(Light Water Reactor・Advanced Reactor,Power and Energy System Symposium)
    NOZAKI Kenichiro; OKAWA Tomio; HOTTA Akitoshi
    Transactions of the Japan Society of Mechanical Engineers Series B, The Japan Society of Mechanical Engineers, 75, 751, 400-402, 2009, In the envisioned high-power density core plant, the degradation of stability is concerned that is attributed to the shortening of rod heat conduction time constant upon the dense fuel grid and the increment of pressure drop caused by the wall friction. To confirm the influence of such degradation on the fuel soundness, the bundle geometry critical power test was held under flow-power oscillation condition which envisages the unstable phenomenon occurring under in the flow transient event. This paper describes the analysis results of the cited test with sub-channel code NASCA, and the discussion of the mechanism of boiling transition under flow-power oscillating condition.
    Japanese
    URL
    DOI URL
  • Variation of critical heat flux by flow oscillation in a small vertical channel
    Toshihiro Murakami; Rei Takei; Tomio Okawa
    International Conference on Nuclear Engineering, Proceedings, ICONE, 4, 303-309, 2009, Peer-reviwed
    International conference proceedings, English
    DOI URL
  • EXPERIMENTAL STUDY ON LIQUID FILM DRYOUT UNDER OSCILLATORY FLOW CONDITIONS
    Yosuke Yamagoe; Taisuke Goto; Tomio Okawa
    ICONE17, VOL 4, 463-470, 2009, Peer-reviwed
    International conference proceedings, English
  • Effect of impingement angle on the outcome of single water drop impact onto a plane water surface
    Tomio Okawa; Takuya Shiraishi; Toshiaki Mori
    Experiments in Fluids, 44, 2, 331-339, Feb. 2008, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Measurement of the deposition rate of droplets in a vertical tube containing a flow obstacle
    Tomio Okawa; Akio Kotani; Naoya Shimada; Isao Kataoka
    NUCLEAR TECHNOLOGY, 158, 2, 304-313, May 2007, Peer-reviwed
    Scientific journal, English
  • Simultaneous measurement of void fraction and fundamental bubble parameters in subcooled flow boiling
    Tomio Okawa; Hayato Kubota; Tatsuhiro Ishida
    NUCLEAR ENGINEERING AND DESIGN, 237, 10, 1016-1024, May 2007, Peer-reviwed
    Scientific journal, English
    DOI URL
  • On the deposition rate of droplets in annular flow around a flow obstacle
    Tomio Okawa; Takayuki Fujita; Jun Minamitani; Isao Kataoka
    Multiphase Science and Technology, 19, 4, 305-321, 2007, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Single water drop impingement onto a falling water film
    Tomio Okawa; Takuya Shiraishi; Takeshi Tada; Isao Kataoka
    FEDSM 2007: PROCEEDINGS OF THE 5TH JOINT ASME/JSME FLUIDS ENGINEERING SUMMER CONFERENCE, VOL 2, PTS A AND B, 317-322, 2007, Peer-reviwed
    International conference proceedings, English
  • Production of secondary drops during the single water drop impact onto a plane water surface
    Tomio Okawa; Takuya Shiraishi; Toshiaki Mori
    Experiments in Fluids, 41, 6, 965-974, Dec. 2006, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Numerical simulation of two-dimensional bubbles initially flattened along a flat plate
    T Okawa; Kataoka, I; M Mori
    NUMERICAL HEAT TRANSFER PART A-APPLICATIONS, 49, 4, 393-409, Sep. 2006, Peer-reviwed
    Scientific journal, English
    DOI URL
  • An experimental study on the mass transfer rate of droplets in annular two-phase flow
    T Okawa; N Shimada; A Kotani; Kataoka, I
    JSME INTERNATIONAL JOURNAL SERIES B-FLUIDS AND THERMAL ENGINEERING, 49, 2, 271-278, May 2006, Peer-reviwed
    Scientific journal, English
  • A STUDY ON SECONDARY DROPS PRODUCED BY DROPLET COLLISION WITH A LIQUID FILM
    Tomio Okawa; Toshiaki Mori; Takuya Shiraishi; Isao Kataoka
    PROCEEDINGS OF THE ASME FLUIDS ENGINEERING DIVISION SUMMER CONFERENCE, VOL 2, 73-77, 2006, Peer-reviwed
    International conference proceedings, English
  • Correlations for the mass transfer rate of droplets in vertical upward annular flow
    T Okawa; Kataoka, I
    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 48, 23-24, 4766-4778, Nov. 2005, Peer-reviwed
    Scientific journal, English
    DOI URL
  • On the rise paths of single vapor bubbles after the departure from nucleation sites in subcooled upflow boiling
    T Okawa; T Ishida; Kataoka, I; M Mori
    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 48, 21-22, 4446-4459, Oct. 2005, Peer-reviwed
    Scientific journal, English
    DOI URL
  • Bubble rise characteristics after the departure from a nucleation site in vertical upflow boiling of subcooled water
    T Okawa; T Ishida; Kataoka, I; M Mori
    NUCLEAR ENGINEERING AND DESIGN, 235, 10-12, 1149-1161, May 2005, Peer-reviwed
    Scientific journal, English
    DOI URL
  • 3519 A Visual Study of Forced-Convective Subcooled Flow Boiling
    OKAWA Tomio; ISHIDA Tatsuhiro; KATAOKA Isao; MORI Michitsugu
    The proceedings of the JSME annual meeting, The Japan Society of Mechanical Engineers, 2005, 195-196, 2005, Vapor bubbles in water subcooled flow boiling were observed visually to investigate the bubble rise characteristics after the departure from a nucleation site and the mechanism of the increase of void fraction with wall heat flux. Three typical bubble rise paths were observed in the present experimental setup: some bubbles slid upward the vertical wall for long distance, while other bubbles were detached from the wall after sliding for several millimeters and then migrated toward the bulk liquid; after the migration, some of the detached bubbles were collapsed in subcooled liquid but others remained close to the wall and were reattached eventually to the wall. It was suggested that the variation in bubble shape from flattened to more rounded was of primary importance for the occurrence of bubble detachment. The dependence of void fraction on heat flux was influenced significantly by the mass flux: the void fraction increased smoothly with heat flux at low mass flux while the increase of void fraction with heat flux was almost negligible near the onset of nucleate boiling (ONB) at high mass flux. It was considered that the difference in bubble size caused the difference in the dependence of void fraction on heat flux.
    Japanese
    DOI URL
  • Flow regimes of upward gas - Liquid two-phase flow in a vertical pipe with an axisymmetic sudden expansion
    Koichi Kondo; Kenji Yoshida; Tadayoshi Matsumoto; Tomio Okawa; Isao Kataoka
    Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, Japan Society of Mechanical Engineers, 71, 711, 2679-2685, 2005, Peer-reviwed
    Scientific journal, Japanese
    DOI URL
  • Void fraction distribution of upward bubbly flow in a vertical pipe with sudden expansion
    Koichi Kondo; Kenji Yoshida; Tadayoshi Matsumoto; Tomio Okawa; Isao Kataoka
    Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, Japan Society of Mechanical Engineers, 71, 703, 796-803, 2005, Peer-reviwed
    Scientific journal, Japanese
    DOI URL
  • Prediction of critical heat flux in annular flow using a film flow model
    T Okawa; A Kotani; Kataoka, I; M Naito
    JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 40, 6, 388-396, Jun. 2003, Peer-reviwed
    Scientific journal, English
  • Behavior of a Vapor Bubble after the Detachment from a Nucleation Site in a Vertical Heated Tube
    OKAWA Tomio; TORIMOTO Kazuhiro; NISHIURA Masanori; KATAOKA Isao; MORI Michitsugu
    The proceedings of the JSME annual meeting, The Japan Society of Mechanical Engineers, 2003, 265-266, 2003, The motion of a vapor bubble after the detachment from a nucleation site in a vertical heated tube was visually observed using two high speed video cameras. It was revealed from video images that the bubble rise path after the detachment is significantly affected by the two parameters : liquid flowrate and bubble size. Almost all the bubbles slid along the vertical wall at low liquid flowrate while intermediate sized bubbles lifted-off the wall in the horizontal direction at higher liquid flowrate. The two parameters would hence have important role for the heat transfer rate, condensation rate and the critical heat flux in flow boiling. A simple Lagrangian simulation was also carried out to describe qualitatively the effects of the two parameters.
    Japanese
    DOI URL
  • Experimental Observation of Single Bubbles Rising in High Temperature Liquids
    OKAWA Tomio; KANAI Naotetsu; KATAOKA Isao; MORI Michitsugu
    The proceedings of the JSME annual meeting, The Japan Society of Mechanical Engineers, 2003, 269-270, 2003, The motion of single bubbles in high temperature water were experimentally observed to elucidate the effect of Morton number on its rise characteristics. In the present experiments, the rise velocity was not significantly affected by the fluid temperature within the range of bubble size of 1-3mm. This would be because the rise velocity is governed by surface tension rather than viscosity in this condition. It was revealed that the rise velocity of vapor bubble is affected by the heat flux to generate bubbles. This would imply that the condition at the detachment from heater surface has the effect on bubble rise characteristics. Also, the m3ethod to estimate the size of bubble exhibiting rise path oscillation from video image was proposed.
    Japanese
    DOI URL
  • Experimental observation of single bubble rise characteristics in various situations
    Tomio Okawa; Tomoe Tanaka; Kazuhiro Torimoto; Masanori Nishiura; Isao Kataoka
    American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FED, 257, 1 B, 861-866, 2002, Peer-reviwed
    International conference proceedings, English
    DOI URL
  • Mechanistic prediction of dryout heat flux in annular two-phase flow
    Tomio Okawa; Saeyun Kim; Isao Kataoka; Masanori Naitoh
    International Conference on Nuclear Engineering, Proceedings, ICONE, 3, 429-435, 2002, Peer-reviwed
    International conference proceedings, English
    DOI URL

MISC

  • ヒートパイプの作動液としてのナノ流体の利用
    大川富雄
    Lead, Jan. 2025, 伝熱, 64, 266, 32-37, Japanese, Invited, Introduction scientific journal
  • Flow Boiling CHF: Liquid Film Dryout and DNB
    Tomio Okawa
    Lead, 18 Aug. 2024, Lecture Note of Summer Seminar on Heat Transfer in Tianjin University, English, Invited, Lecture materials
  • 技術ロードマップから見る2030年の社会 第6回 動力エネルギーシステム分野/エンジンシステム分野
    中田俊彦; 氣駕尚志; 大川富雄; 浅野等; 今村宰; 塚本達郎; 内田登; 北村高明; 北村高明
    2023, 日本機械学会誌, 126, 1255, 0021-4728, 202302289752426057
  • Dr. Romney B. Duffey on His 80th Birthday
    Igor Pioro; Richard R. Schultz; Hideki Kamide; Sama Bilbao y Leon; Nils Diaz; Alexander V. Bychkov; Leon Cizelj; Francesco D’Auria; Yanping Huang; Yasuo Koizumi; Tomio Okawa; Robert Walker; Robert Youngblood; Enrico Zio
    01 Jul. 2022, Journal of Nuclear Engineering and Radiation Science, 8, 030201, 1-4, Invited, Others, 2332-8983, 2332-8975, 85133889436
    DOI URL
  • Synchronized images during falling liquid film cooling
    Yutaro Umehara; Tomio Okawa
    Last, Mar. 2022, 混相流, 36, 1, Japanese, Invited, Others, False
  • 原子炉における機構論的限界熱流束評価技術の 確立に向けて Part 1：軽水炉燃料における現在の限界熱流束予測手法 と課題
    大川富雄、淀忠勝、成島勇気、高野賢治
    Lead, 日本原子力学会, Dec. 2021, 日本原子力学会誌, 63, 12, 1-5, Japanese, Invited, Introduction scientific journal, False
  • 原子炉における機構論的限界熱流束評価技術の確立に向けて Part 2：機構論的限界熱流束予測評価手法確立に向けた研究とその課題 と課題
    大川富雄, 森昌司, 劉維, 小瀬裕男, 吉田啓之, 小野綾子
    Lead, 日本原子力学会, Dec. 2021, 日本原子力学会誌, 63, 12, 1-5, Japanese, Invited, Introduction scientific journal, False
  • Nanoparticle coating in heat pipe design for miniaturised cooling
    Tomio Okawa, Menglei Wang
    Lead, Research Outreach, 02 Jul. 2021, Research Outreach, 123, 22-25, English, Invited, Introduction commerce magazine, True, 2517-7028
  • Fundamentals of Thermal and Nuclear Power Generation
    Yasuo Koizumi; Tomio Okawa; Shoji Mori
    01 Jan. 2021, Fundamentals of Thermal and Nuclear Power Generation, 1-301, Others, 85126373605
    DOI URL
  • 繊維状金属焼結管に関する伝熱および圧力損失の実験的解明—Method for improving air-side heat transfer using metal sintered body
    渡邊 廉; 榎木 光治; 大友 優甫; 小林 拓都; 大川 富雄; 秋澤 淳; 上田 祐樹
    [東京] : 日本冷凍空調学会, 2019, 日本冷凍空調学会年次大会講演論文集 Proceedings of the JSRAE Annual Conference, Japanese, 2188-5397, 40022801664
    URL
  • Heat transfer improvement in heat exchanger for thermoacoustic engine by sintered porous pipes
    OTOMO Yusuke; ENOKI Koji; KOBAYASHI Takuto; UEDA Yuki; AKISAWA Atsushi; KAWASAKI Jumpei; OKAWA Tomio
    Recently thermoacoustic engine is being used to recover latent and sensible heat. However, the heat exchanger which is loaded by thermoacoustic engine has low performance because of large thermal resistance of the gas side. The purpose of this study is improving heat exchanger equipped with sintered fiber metal porous materials into the pipes in order to enhance the heat flux. Porous materials have the characteristic of mixing the fluid in contact and expanding heat transfer area. In addition, these heat pipes have a less contact thermal resistance because of the sintered porous materials into tube wall. Conducted experiments to measure heat exchange for each pipes show that porous pipes have between 1.5 times and 2 times better heat exchange performance than conventional ones under the condition Reynolds number Re = 4500. Furthermore, heat exchanger using sintered fiber metal porous materials increase until 10 times the heat transfer rate in comparison with the conventional heat exchangers., The Japan Society of Mechanical Engineers, 2019, The Proceedings of the National Symposium on Power and Energy Systems, 2019.24, E111, Japanese, 2424-2950, 130007773973
    URL
    DOI URL
  • サブクール沸騰熱伝達におけるポーラス伝熱面を用いた伝熱面拡大と流体の攪拌の影響—The effects of enhancement porous surface area and roily coolant in forced convection subcooled boiling heat transfer
    大箸 淳記; Edgar SANTIAGO-GALICIA; 熊取 弘祐; 榎木 光治; 大川 富雄
    [東京] : 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, Japanese, 2188-5397, 40021357557, BB18860123
    URL
  • ミニチャンネル内垂直上昇流における水の沸騰熱伝達特性に関する研究—Boiling Heat Transfer of Water Flowing Vertically Upward in a Circular Mini-channel
    中村 太一; 大野 正晴; MD. AMIRUL ISLAM; 榎木 光治; 大川 富雄; 小澤 守
    [東京] : 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, Japanese, 2188-5397, 40021297053, BB18860123
    URL
  • 20314 A study on void development in subcooled flow boiling
    KAJIHARA Tomoyuki; MIYANO Naoki; OKAWA Tomio; KUDO Yoshiro
    Subcooled flow boiling plays an important role in boiling water reactors because it influences the heat transfer performance from fuel rods, two-phase flow stability, and neutron moderation characteristics. In this work, flow visualization of water subcooled flow boiling in a vertical heated channel was carried out to investigate the mechanisms of void fraction development. It was observed that with an increase in the wall heat flux, new nucleation sites were activated and larger bubbles were produced at low frequency. It was considered that these large bubbles significantly contributed to the void fraction development., The Japan Society of Mechanical Engineers, 14 Mar. 2014, 日本機械学会関東支部総会講演会講演論文集, 2014, 20, "20314-1"-"20314-2", Japanese, 110009949384, AA11902161
  • S083031 Visualization Study to Investigate the NVG Mechanisms in Subcooled Flow Boiling
    AHMADI Rouhollah; UENO Tatsuya; OKAWA Tomio
    Measurement of void fraction and observation of bubble dynamics were carried out to investigate the mechanisms causing the net vapor generation (NVG) in subcooled upward flow boiling. The working fluid was distilled water and the heated surface of rather low contact angle was used in the present experiment Since no bubbles could stay at their nucleation sites even at the onset of nucleate boiling (ONB), departure of bubbles from the nucleation sites was not the cause of NVG in the present experimental setup. Following the departure from the nucleation sites, bubbles were lifted off the heated surface to be propelled into the subcooled bulk liquid at low pressures whilst they slid along the vertical heated surface at elevated pressures. As a result, the bubble life time at ONB was considerably shorter in the experiments conducted under low pressures. The distinct difference of bubble dynamics suggested that the mechanisms of NVG are dependent on the system pressure. At low pressures, some bubbles could be reattached to the surface after the lift-off at sufficiently low liquid subcooling Since the bubble life time was markedly elongated, the reattachment of bubbles to the vertical heated surface was considered to trigger the NVG. It was also found that the bubble reattachment usually took place following the coalescence of bubbles produced successively at the same nucleation site. The stochastic bubble motion induced by coalescence was hence considered to be a key phenomenon causing NVG. The NVG mechanism at high pressures is investigated in future studies., The Japan Society of Mechanical Engineers, 09 Sep. 2012, Mechanical Engineering Congress, Japan, 2012, "S083031-1"-"S083031-5", Japanese, 110009993565, AA12588255
  • ICONE19-43556 Bubble behavior in subcooled flow boiling in a vertical rectangular channel
    Ahmadi Rouhollah; Ueno Tatsuya; Okawa Tomio
    In this study bubble behavior in subcooled flow boiling in an upward rectangular channel was discussed. Filtrated and deionized tap water was used as a working fluid. Heated surface is produced by cupper with high wetability or low contact angle (18°). Subcooled flow boiling is beginning with onset of nucleate boiling (ONB) which surface temperature is higher than saturation temperature while liquid temperature is less than saturation temperature. At various pressure, mass fluxes and inlet temperatures ONB heat flux is detected within observation incipient nucleate bubbles through high speed video camera. Comparing with available ONB correlations, it is revealed that surface wettability is a significant parameter. Among ΔT_ correlation only Basu et al. (2002)'s correlation has a good consistency with experimental data, and other correlations are most underpredicted. Nucleation rate of bubbles after ONB remain in very small amount until a specific condition nominated onset of significant void (OSV) or incipient point of net vapor generation (IPNVG) that void fraction drastically increased. Levy (1967) was the first to postulate bubble departure mechanism for OSV and many researchers believed this assumption and analytically and empirically proposed OSV correlation. However, in all the experimental conditions even at incipient bubble nucleation, bubbles are observed depart or lift-off from activated nucleation site on the heated surface. Bubble nucleation behavior as whether bubble Lift-off from hot surface or sliding along it are investigated. It is performed for low void fraction condition. It is concluded that lifting-off condition occurred when bubble size and subcooling temperature is high and sliding phenomena in the opposite condition happened. Bubble size dramatically drop down after atmospheric pressure. This categorization is useful for developing new OSV mechanism regarded to actual situation., The Japan Society of Mechanical Engineers, 01 Aug. 2011, Proceedings of the ... International Conference on Nuclear Engineering. Book of abstracts : ICONE, 2011, 19, "ICONE1943556-1"-"ICONE1943556-7", English, 110009956960, AA1190311X
  • B110 Analytical Study on Boiling Transition under Flow-Power Oscillating Condition for Hyper ABWR
    Nozaki Kenichiro; Okawa Tomio; Hotta Akitoshi; Ikeda Hideaki
    In the envisioned high-power density core plant, the degradation of stability is concerned that is attributed to the shortening of rod heat conduction time constant upon the dense fuel grid and the increment of pressure drop caused by the wall friction. To confirm the influence of such degradation on the fuel soundness, the bundle geometry critical power test was held under flow-power oscillation condition which envisages the unstable phenomenon occurring under in the flow transient event. This paper describes the analysis results of the cited test with sub-channel code NASCA, and the discussion of the mechanism of boiling transition under flow-power oscillating condition., The Japan Society of Mechanical Engineers, 18 Jun. 2008, National Symposium on Power and Energy Systems, 2008, 13, 85-88, Japanese, 110007703804, AA11901431
  • 909 Experiments on the Deposition Rate of Droplets in a Flow Channel Containing an Obstacle
    Fujita Takayuki; Minamitani Jun; Okawa Tomio; Kataoka Isao
    The Japan Society of Mechanical Engineers, 17 Mar. 2006, 関西支部講演会講演論文集, 2006, 81, "9-8", Japanese, 110006669298, AN00360659
  • OS8-06 An experimental study on the mass transfer rate of droplets in annular two-phase flow
    OKAWA Tomio; KOTANI Akio; SHIMADA Naoya; KATAOKA Isao
    The deposition rate of droplets in annular two-phase flow in a small vertical tube was measured using the double film extraction method. Based on the present experimental data and available ones, new phenomenological models for the deposition rate and entrainment rate were developed. It was also shown experimentally that the deposition rate is markedly increased if a small flow obstacle is placed in the test section tube. An empirical correlation to account the influence of flow obstacle on deposition rate was proposed., The Japan Society of Mechanical Engineers, 28 Jun. 2005, National Symposium on Power and Energy Systems, 2005, 10, 135-138, Japanese, 110006187878, AA11901431
  • An experimental study on bubble rise path after the departure from a nucleation site in vertical upflow boiling
    T Okawa; T Ishida; Kataoka, I; M Mori
    Mar. 2005, EXPERIMENTAL THERMAL AND FLUID SCIENCE, 29, 3, 287-294, English, 0894-1777, 1879-2286, WOS:000226571600005
    DOI URL
  • Experiments for liquid phase mass transfer rate in annular regime for a small vertical tube
    T Okawa; A Kotani; Kataoka, I
    Jan. 2005, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 48, 3-4, 585-598, English, 0017-9310, WOS:000226625300011
    DOI URL
  • Applicability of One-Dimensional Two-Fluid Model to Air-Water Bubbly Flow in a Vertical Pipe with Sudden Expansion
    KONDO Koichi; YOSHIDA Kenji; OKAWA Tomio; KATAOKA Isao
    日本原子力学会, 25 Dec. 2004, Transactions of the Atomic Energy Society of Japan, 3, 4, 323-330, Japanese, 1347-2879, 10013705001, AA11643165
    URL
  • Effects of a flow obstacle on the deposition rate of droplets in annular two-phase flow
    T Okawa; A Kotani; N Shimada; Kataoka, I
    Sep. 2004, JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 41, 9, 871-879, English, 0022-3131, WOS:000225245100001
    DOI URL
  • Prediction of the critical heat flux in annular regime in various vertical channels
    T Okawa; A Kotani; Kataoka, I; M Naitoh
    Apr. 2004, NUCLEAR ENGINEERING AND DESIGN, 229, 2-3, 223-236, English, 0029-5493, WOS:000221080400010
    DOI URL
  • 610 Liquid Velocity and Turbulent Intensity Distributions of Bubbly Flow in a Vertical Pipe with Sudden Expansion
    KONDO Koichi; YOSHIDA Kenji; OKAWA Tomio; KATAOKA Isao
    Experimental study was made on the multi-dimensional behavior of upward gas-liquid two-phase flow through a vertical pipe with an axisymmetric sudden expansion, which is one of the typical multi-dimensional channel geometries. In this study, the liquid velocity and turbulent intensity along the flow direction at the below and above of the sudden expansion were measured by using a hot-film anemometer for various flow conditions. The development of the liquid velocity and the turbulent intensity along the flow direction of the downstream of the sudden expansion showed quite complicated behaviors depending upon flow rates of gas and liquid phases and bubble size. These results would become significant data for the development of multi-dimensional analysis in two-phase flow., The Japan Society of Mechanical Engineers, 17 Mar. 2004, 関西支部講演会講演論文集, 2004, 79, "6-19"-"6-20", Japanese, 110004301348, AN00360659
  • Experiments for equilibrium entrainment fraction in a small vertical tube
    2004, Proceedings of 5th International Conference on Multiphase Flow, Yokohama, Japan
  • Bubble rise characteristics after the departure from a nucleation site in water saturated and subcooled flow boiling
    2004, Proceedings of Third International Symposium on Two-Phase Flow Modelling and Experimentation, Pisa, Italy
  • Prediction of void fraction distribution for turbulent bubble flow in a vertical pipe with sudden expansion
    2004, Proceedings of Third International Symposium on Two-Phase Flow Modelling and Experimentation, Pisa, Italy
  • Correlation for the deposition rate of droplets in vertical upward annular two-phase flow
    2004, Proceedings of 6th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operation and Safety, Nara, Japan
  • Experiments for deposition rate of droplets in a small diameter tube
    2004, Proceedings of Sixth International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operation and Safety, Nara, Japan
  • 混相流ハンドブック
    2004, 朝倉書店
  • Experiments for equilibrium entrainment fraction in a small vertical tube
    2004, Proceedings of 5th International Conference on Multiphase Flow, Yokohama, Japan
  • Prediction of void fraction distribution for turbulent bubble flow in a vertical pipe with sudden expansion
    2004, Proceedings of Third International Symposium on Two-Phase Flow Modelling and Experimentation, Pisa, Italy
  • Bubble rise characteristics after the departure from a nucleation site in water saturated and subcooled flow boiling
    2004, Proceedings of Third International Symposium on Two-Phase Flow Modelling and Experimentation, Pisa, Italy
  • Correlation for the deposition rate of droplets in vertical upward annular two-phase flow
    2004, Proceedings of 6th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operation and Safety, Nara, Japan
  • Experiments for deposition rate of droplets in a small diameter tube
    2004, Proceedings of Sixth International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operation and Safety, Nara, Japan
  • Handbook of Multiphase Flow
    2004, Asakura Pub.
  • Numerical Simulation of Liquid Film Falling down an Inclined Flat Plate
    Okawa Tomio; Kataoka Isao
    The Japan Society of Mechanical Engineers, 18 Sep. 2003, Fluids engineering conference ..., 2003, 158-158, Japanese, 1348-2882, 110002509974, AA11284390
  • Temperature effect on single bubble rise characteristics in stagnant distilled water
    T Okawa; T Tanaka; Kataoka, I; M Mori
    Feb. 2003, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 46, 5, 903-913, English, 0017-9310, WOS:000180522900013
    DOI URL
  • Studies on the modification characteristics of gas-phase turbulence in annular flow
    TANAKA Hidenobu; YOSHIDA Kenji; MATSUMOTO Tadayoshi; OKAWA Tomio; KATAOKA Isao; MATSUURA Keizo
    Experimental and numerical studies were made to investigate the effects of liquid film to gas-phase turbulence modification on annular flow. By using the hot-wire anemometer, time averaged axial velocity profile, turbulence fluctuation profile, energy spectrum, and auto-correlation coefficient of gas-phase axial velocity component are measured. By using the point-electrode prove, the time-averaged liquid film thickness is also measured. Considering the effect of wavy interface of liquid film, numerical simulations for gas-phase turbulence structures in annular flow are carried out. Liquid film is assumed and modeled to be the surface roughness of the wall moving with the velocity of liquid film., The Japan Society of Mechanical Engineers, 2003, 関西支部講演会講演論文集, 2003, 78, "14-33"-"14-34", Japanese, 110002493995, AN00360659
  • Bubble characteristics of steam-water two-phase flow in a large-diameter pipe
    K Yoneda; A Yasuo; T Okawa
    Aug. 2002, EXPERIMENTAL THERMAL AND FLUID SCIENCE, 26, 6-7, 669-676, English, 0894-1777, WOS:000178284700010
    DOI URL
  • Bubble characteristics of steam-water two-phase flow in a large-diameter pipe
    K Yoneda; A Yasuo; T Okawa
    Aug. 2002, EXPERIMENTAL THERMAL AND FLUID SCIENCE, 26, 6-7, 669-676, English, 0894-1777, WOS:000178284700010
    DOI URL
  • Numerical simulation of lateral phase distribution in turbulent upward bubbly two-phase flows
    T Okawa; Kataoka, I; M Mori
    Apr. 2002, NUCLEAR ENGINEERING AND DESIGN, 213, 2-3, 183-197, English, 0029-5493, WOS:000175213500008
    DOI URL
  • Flow Regime of Vertical Upward Two-Phase Flow through Round Tube with Sudden Expansion
    KONDO Koichi; HASHIMOTO Tomoyuki; YOSHIDA Kenji; MATSUMOTO Tadayoshi; OKAWA Tomio; KATAOKA Isao
    Experimental studies were made on the multi-dimensional behavior of upward gas-liquid two-phase flow through the vertical round tube with an axisymmetric sudden expansion, which is one of the typical multi-dimensional channel geometry. The aims of this study are to clarify the multi-dimensional behavior of bubbly or slug flow affected by sudden expansion channel geometry, and to accumulate the experimental data for two-phase flow analysis, which is applicable to predict with appropriate accuracy the multi-dimensional its behavior. As the first step in this study, direct observation using high-speed video camera was performed and revealed the multi-dimensional dynamic flow behavior affected by the sudden expansion part. Characteristic phenomena were observed such as bubble break-up, deformation due to the strong share of liquid flow, or liquid micro jet penetration through the gas-slug, and so on. The void fraction profiles in sudden expansion were also measured using a pointed-electrode resistivity probe. From these results, the flow regime map at the below or above of the sudden expansion part were classified., The Japan Society of Mechanical Engineers, 2002, 関西支部講演会講演論文集, 2002, 77, "11-17"-"11-18", Japanese, 110002493065, AN00360659
  • Prediction of dryout heat flux using film flow model
    2002, Thermal Science and Engineering, Vol. 10, No. 4, pp. 33-34
  • Critical power analysis with mechanistic models for nuclear fuel bundles, (I) Models and verifications for boiling water reactor application
    M Naitoh; T Ikeda; K Nishida; T Okawa; Kataoka, I
    Jan. 2002, JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 39, 1, 40-52, English, 0022-3131, WOS:000174437800006
  • New entrainment rate correlation in annular two-phase flow applicable to wide range of flow condition
    T Okawa; T Kitahara; K Yoshida; T Matsumoto; Kataoka, I
    Jan. 2002, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 45, 1, 87-98, English, 0017-9310, WOS:000172076200009
    DOI URL
  • Photosynthetic productivity of conical helical tubular photobioreactors incorporating Chlorella sp under various culture medium flow conditions
    M Morita; Y Watanabe; T Okawa; H Saiki
    Jul. 2001, BIOTECHNOLOGY AND BIOENGINEERING, 74, 2, 136-144, English, 0006-3592, WOS:000169296600006
    DOI URL
  • 614 A study on forced convective transient gas-liquid two-phase flow
    TSUJITA Yoshihiro; NAKAZUMI Minoru; OKAWA Tomio; MATSUMOTO Tadayoshi; KATAOKA Isao
    This paper shows the experimental and analytical study of forced convective transient airwater two-phase flow. In experiment, the flow rates of water and air were independently at the entrance, the transient bubbly two-phase flow was realized in vertical channel. Then, measurement the transient variation of pressure, differential pressure and void fraction at measuring position. Concerning the measure of void fraction , use the character of air which is not conductive. Moreover , supply the data for the analysis., The Japan Society of Mechanical Engineers, 16 Mar. 2001, 関西支部講演会講演論文集, 2001, 76, "6-25"-"6-26", Japanese, 110002492115, AN00360659
  • 615 Study On Transient Gas and Liquid Two-Phase Natural Circulation
    NISHIMORI Yutaka; AOYAMA Shigeki; OKAWA Tomio; MATSUMOTO Tadayoshi; KATAOKA Isao
    This paper is an investigation of the transient two-phase natural circulation. Laboratory equipment was composed of single-phase flow section and two-phase flow section. Single-phase flow section was 4.5m in length. Two-phase flow section was vertical and 2m in length. Flow is vertically upward. The inner diameter of the pipe was 20mm. The measurement was carried out on transient variation of the pressure, the void fraction and the flow rate of water induced by the supplied air flow. Comparisons are made between the data and the calculations based on basic equation of two-phase flow., The Japan Society of Mechanical Engineers, 16 Mar. 2001, 関西支部講演会講演論文集, 2001, 76, "6-27"-"6-28", Japanese, 110002492117, AN00360659
  • Numerical Simulation of Single Bubbles Located in Turbulent Flow in Vertical Pipes Using Bubble Tracking Method
    OKAWA Tomio; ARAKI Koji; YOSHIDA Kenji; MATSUMOTO Tadayoshi; KATAOKA Isao; MORI Michitsugu
    日本混相流学会, 2001, Japanese journal of multiphase flow, Vol. 15, No. 2, pp. 165-174, 2, 165-174, English, 0914-2843, 10010263636, AN10088286
    URL
    DOI URL
  • Numerical implementation of interfacial drag force for one-dimensional, two-way bubble tracking method
    T Okawa; Y Suzuki; Kataoka, I; M Aritomi; M Mori
    Apr. 2000, JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 37, 4, 387-396, English, 0022-3131, 1881-1248, WOS:000087390500008
    DOI URL
  • Numerical implementation of interfacial drag force for one-dimensional, two-way bubble tracking method
    T Okawa; Y Suzuki; Kataoka, I; M Aritomi; M Mori
    Apr. 2000, JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 37, 4, 387-396, English, 0022-3131, 1881-1248, 10004752848, WOS:000087390500008
    DOI URL
  • 901 Analysis of Flow Characteristics in Annular Dispersed Flow by a Multi-Fluid Model
    KITAHARA Tsuyoshi; YOSHIDA Kenji; OKAWA Tomio; MATSUMOTO Tadayoshi; KATAOKA Isao
    Prediction of dryout in annular-dispersed flows in the boiling heat transfer is particularly important. A three-fluid model is often used for analyses of the annular-dispersed flows ; its applicability to the prediction of the flows in round tubes has been well validated. However its applicability to the annular-dispersed flows in more complicated channels is uncertain. In the present study, the computer program based on a multi-fluid model is developed for predicting the flow properties of annular-dispersed flow accurately in complicated channels and applied it to the annular-dispersed flow in annuli., The Japan Society of Mechanical Engineers, 16 Mar. 2000, 関西支部講演会講演論文集, 2000, 75, "9-1"-"9-2", Japanese, 110002491711, AN00360659
  • 902 Analysis of Turbulent Structure and Void Fraction Distribution in Boiling Two-Phase Flow with Various Cross Section Tube
    MUTA Masayoshi; KIM Saeyun; YOSHIDA Kenji; OKAWA Tomio; MATSUMOTO Tadayoshi; KATAOKA Isao
    Analyses were carried out on turbulence structure and void fraction distribution in boiling two-phase flow for various channel geometries. Basic conservation equations of mass, mometum and energy and turbulence in boiling two-phase flow were solved couppled with basic equation of void fraction distribution. Turbulence source terms of two phase flow were considered and fully two-way coupling model between gas and liquid chases used. The results show that bubble number density and void fraction distributions in boiling two-phase flow in rectangular channel has sharp wall peak in the central region of the channel whereas it has flattened distribution near wall region which reasonably agree with experimental observation. It is indicated that multi-dimensional turbulence structure is quite important in predicting void fraction distribution in boiling two-phase flow., The Japan Society of Mechanical Engineers, 16 Mar. 2000, 関西支部講演会講演論文集, 2000, 75, "9-3"-"9-4", Japanese, 110002491713, AN00360659
  • 626 Development of Numerical Simulation Method of Dispersed Two-Phase Flow Using a Euler-Lagrange Model
    ARAKI Koji; HASHIMOTO Katsuteru; OKAWA Tomio; YOSHIDA Kenji; MATSUMOTO Tadayoshi; KATAOKA Isao
    A bubble tracking method is one of the most promising candidates for partly replacing the two-fluid model, which has been widely used in two-phase flow engineering analysis. In the present study, we confirmed the usefulness of this method by calculating the motion of the bubbles rising in the turbulent flow in the vertical rectangular duct, taking into account the lateral lift force, wall force acting on the bubbles, and reasonable agreement is found with the available experimental data., The Japan Society of Mechanical Engineers, 16 Mar. 2000, 関西支部講演会講演論文集, 2000, 75, "6-51"-"6-52", Japanese, 110002491591, AN00360659
  • Mathematical well-posedness of a two-fluid equations for bubbly two-phase flows
    Tomio Okawa; Isao Kataoka
    Japan Society of Mechanical Engineers, 2000, Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 66, 646, 1281-1287, Japanese, 0387-5016, 110002393130, 71449125032
    DOI URL
  • Mathematical well-posedness of a two-fluid equations for bubbly two-phase flows
    Tomio Okawa; Isao Kataoka
    Japan Society of Mechanical Engineers, 2000, Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 66, 646, 1281-1287, Japanese, 0387-5016, 71449125032
    DOI URL
  • New interfacial drag force model including effect of bubble wake, (II) - Model validation using experimental data of steam-water bubbly flow in large-diameter pipes
    T Okawa; K Yoneda; Zhou, SR; H Tabata
    Nov. 1999, JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 36, 11, 1030-1040, English, 0022-3131, 1881-1248, WOS:000084632400007
    DOI URL
  • New interfacial drag force model including effect of bubble wake, (II) - Model validation using experimental data of steam-water bubbly flow in large-diameter pipes
    T Okawa; K Yoneda; Zhou, SR; H Tabata
    Nov. 1999, JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 36, 11, 1030-1040, English, 0022-3131, 1881-1248, 10002841537, WOS:000084632400007
    DOI URL
  • Numerical Simulation of Turbulence Generation due to Boiling Bubble
    KATAOKA Isao; UCHIDA Kyosuke; MATSUMOTO Tadayoshi; OHKAWA Tomio
    29 Jul. 1999, 年会一般講演, 18, 253-254, Japanese, 1342-8004, 10007478438, AA11169596
  • Effects of Source Terms and Virtual Mass Force on Mathematical Nature of a Two-Fluid Model(2nd Report, Examination of Mathematical Nature)
    OKAWA Tomio; TOMIYAMA Akio
    As is by now well known, partial differential equations based on a one dimensional, one-pressure two fluid model are mathematically ill-posed as an initial-value problem. Up to the present, however, eigenvalue analysis of the two fluid model has been conducted only for a simplified two-fluid model without any source terms, since a necessary condition of well-posedhess can be derived from differential terms only. Consequently, effects of source terms have not been systematically investigated. In the previous report, we proposed the method to examine mathematical nature of the complete two-fluid model including source terms ; the effects of gravity were evaluated using this method. As a result, it was confirmed the two fluid model can be mathematically ill-posed due to source terms. In the present study, the effects of interfacial drag force and wall friction force were examined using the same method. The effects of virtual mass force were also evaluated, since its influence has not been clarified in spite of the fact that it can affect the numerical stability., The Japan Society of Mechanical Engineers, 1999, Transactions of the Japan Society of Mechanical Engineers. Series B., 65, 629, 86-91, Japanese, 0387-5016, 110002395183, AN00187441
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    DOI URL
  • Effects of source terms and vertual mass force on mathematical nature of a two-fluid model(2nd report, Evaluation of mathematical nature)
    Tomio OKAWA; Akio TOMIYAMA
    1999, Transactions of the Japan Society of Mechanical Engineers(Ser. B), 65, 629, 86-91, 0387-5016
    DOI URL
  • New interfacial drag force model including effect of bubble wake, (I) - Model development for steam-water bubbly flow in large-diameter pipes
    T Okawa; K Yoneda; Y Yoshioka
    Dec. 1998, JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 35, 12, 895-904, English, 0022-3131, 1881-1248, 10002080550, WOS:000078458400007
    DOI URL
  • New interfacial drag force model including effect of bubble wake, (I) model development for steam-water bubbly flow in large-diameter pipes
    Tomio Okawa; Kimitoshi Yoneda; Yuzuru Yoshioka
    1998, Journal of Nuclear Science and Technology, 35, 12, 895-904, English, 0022-3131, 0032255042
    DOI URL
  • Effects of Source Terms and Virtual Mass Force on Mathematical Nature of a Two-Fluid Model (1st Report, Effects of Gravity)
    OKAWA Tomio; TOMIYAMA Akio
    According to mathematical theorems on initial-value problem, real-valued characteristic roots are necessary for a system of partial differential equations. However, a one-dimensional, one-pressure two-fluid model has complex-valued characteristic root, so that it is called mathematically ill-posed. Up to the present, eigenvalue analysis of a two-fluid model has been conducted only for a simplified two-fluid model without any source terms. Although these simplified analyses can yield a necessary condition for well-posedness, they cannot give a sufficient condition. A necessary and sufficient condition can be obtained if and only if the eigenvalues of a complete two-fluid model with source terms are evaluated. Furthermore, numerical stability of the two-fluid model is also affected by source terms. The examination of source terms is, hence, indispensable to clarify the mathematical and numerical nature of a two-fluid model. In this report, the method to examine the mathematical nature of a complete two-fluid model with source terms is presented. Based on this method, it is revealed that the degree of ill-posedness of the two-fluid model is greatly affected by gravity., The Japan Society of Mechanical Engineers, 1998, Transactions of the Japan Society of Mechanical Engineers. Series B., 64, 624, 2472-2477, Japanese, 0387-5016, 110002397175, AN00187441
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    DOI URL
  • Numerical Simulation of CAES Champagne Effect (2nd Report, Preliminary Calculation for Plant Design)
    OKAWA Tomio; TANAKA Nobukazu; YAMAMOTO Ryosuke; MATSUI Goichi; MONJI Hideaki
    Evaluation of champagne effect is indispensable for successful commercialization of a compressed air energy storage (CAES) system which is one of the most promising candidates of energy storage system. In the present study, we examined optimum design of the CAES system through numerical calculations of the champagne effect based on a two-fluid model. As a result, the following conclusions were obtained. (1) Charging rate of air into a lower reservoir should be gradually changed during startup and shutdown periods to avoid pressure oscillation in the lower reservoir. (2) If the water level in the lower reservoir is too low when the charging is finished, the inertial force makes the water level enter into the U-bend, which also induces the pressure oscillation in the lower reservoir. (3) If appropriate procedures are adopted during the startup and shutdown period of air charging system, the water level in the lower reservoir does not enter into the U-bend. The construction cost can hence be reduced by shortening the U-bend., The Japan Society of Mechanical Engineers, 1998, Transactions of the Japan Society of Mechanical Engineers. Series B., 64, 628, 3964-3969, Japanese, 0387-5016, 110002397383, AN00187441
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    DOI URL
  • Numerical Simulation of CAES Champagne Effect (Ist Report, Development of Computer program
    OKAWA Tomio; TANAKA Nubukazu; YAMAMOTO Ryosuke; MATSUI Goichi; MONJI Hideaki
    Fluctuations of electric power demands in Japan are so heavy that development of electric sources for peak load generation is an important problem. Compressed air energy storage (CAES) system is one of the most promising candidates of energy storage system, and considered to follow pumping-up electric power plants. The CAES system stores compressed air in an underground reservoir using low-cost power from base load plants during off-peak periods. The stored air is used for gas-turbine power generation during peak periods. For successful design of the CAES system, accurate prediction of CAES champagne effect is required to avoid a loss of the stored air caused by blowout. In the present study, a computer program based on a one-dimensional two-fluid model including a simple gas release model was developed for prediction of the CAES champagne effect. This program was applied to simulation of experimental results of a high-solubility carbon dioxide/water laboratory model of the CAES system. The computer program developed was found to show good agreement with the experimental results if the mass transfer coefficient, that determines the gas release rate, was set to 0.4 mm/s., The Japan Society of Mechanical Engineers, 1998, Transactions of the Japan Society of Mechanical Engineers. Series B., 64, 621, 1398-1404, Japanese, 0387-5016, 110002396944, AN00187441
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    DOI URL
  • Effects of source terms and virtual mass force on mathematical nature of a two-fluid model(1st report, Effect of gravity)
    Tomio OKAWA; Akio TOMIYAMA
    1998, Transactions of the Japan Society of Mecanical Engineers(Ser. B), 64, 624, 2472-2477, 0387-5016
    DOI URL
  • Numerical simulation of CAES champagne effect(2nd report, Preliminary calculation for plant design)
    Tomio OKAWA; Nobukazu TANAKA; Ryosuke YAMAMOTO; Goichi MATSUI; Hideaki MONJI
    1998, Transactions of the Japan Society of Mechanecal Engineers(Ser. B), 64, 628, 3964-3969, 0387-5016
    DOI URL
  • Numerical simulation of CAES champagne effect(1st report, Development of computer program)
    Tomio OKAWA; Nubukazu TANAKA; Ryosuke YAMAMOTO; Goichi MATSUI; Hideaki MONJI
    1998, Transactions of the Japan Society of Mechanical Engineers(Ser. B), 64, 621, 1398-1404, 0387-5016
    DOI URL
  • Numerical Analysis of Performance of Air-lift pump Combined with the Ocean CAES system
    YAMAMOTO Ryosuke; TANAKA Nobukazu; OHKAWA Tomio
    Jul. 1996, 年会一般講演, 15, 447-448, Japanese, 1342-8004, 10002906103, AA11169596
  • 二流体モデルに対する高次風上差分法の適用性(第3報:数値解の精度に関する検討)
    1994, 混相流, 8, 4, 291-300
  • 二流体モデルに対する高次風上差分法の適用性(第2報:二流体モデル方程式に基づく考察)
    1994, 混相流, 8, 2, 126-134
  • Applicability of high-order upwind schemes to two-fluid(1st report, Examination on the accuracy of numerical solutions)
    OHKAWA T.
    1994, Japanese Journal of Multiphase Flow, 8, 4, 291-300, 10004114591, AN10088286
  • Applicability of high-order upwind schemes to two-fluid model(1st report, Examination based on the two-fluid model)
    OHKAWA T.
    1994, Japanese Journal of Multiphase Flow, 8, 2, 126-134, 10004114590, AN10088286
  • 非圧縮性多次元二流体モデルの数値解法(構成方程式の評価に適する解法)
    冨山明男; 片岡勲; 大川富男; 平野雅司
    1993, 機械学会論文集B編, 59, 566, 3003-3008, 0387-5016, 110002402717
    DOI URL
  • 二流体モデルに対する高次風上差分法の適用性(第1報:線形モデル方程式に基づく考察)
    1993, 混相流, 7, 3, 241-249
  • Numerical solution method for incompressible multidimensional two-fluid model(A method suitable for the evaluation of constitutive equations)
    TOMIYAMA A.
    1993, Transactions of the Japan Society of Mechanical Engineers(Ser. B), 59, 566, 3003-3008, 0387-5016, 10004114597
    DOI URL
  • Applicability of high-order upwind schemes to two-fluid model(1st report, Examination Based on a linear model equation for the two-fluid model)
    1993, Japanese Journal of Multiphase Flow, 7, 3, 241-249
  • 二相流数値解析における質量保存式の選択が数値解に及ぼす影響
    1992, 混相流, 6, 4, 395-405
  • Effect of mass ewuations for two-phase flow analyses on numerical solutions
    1992, Japanese Journal of Multiphase Flow, 6, 4, 395-405
  • Numerical experiment on interaction of solitons describing recurrence of initial state
    R. Takahashi; T. Ohkawa
    Springer-Verlag, Jul. 1989, Computational Mechanics, 5, 4, 273-281, English, 0178-7675, 34249975921
    DOI URL
  • Numerical experiment on interaction of solitons describing recurrence of initial state
    R. Takahashi; T. Ohkawa
    Springer-Verlag, Jul. 1989, Computational Mechanics, 5, 4, 273-281, English, 0178-7675, 80005115744, 34249975921
    DOI URL

Books and other publications

  • Thermal and Nuclear Power Generation
    English, Others, Elsevier, 2020
  • 新しい気液二相流数値解析
    コロナ社, 2002
  • Applicability of high-order upwind difference methods to the two-fluid model
    Advances in Multiphase Flow, Elsevier, 1995
  • Applicability of high-order upwind difference methods to the two-fluid model
    Advances in Multiphase Flow(A. Serizawa, T. Fukano, J. Bataille, Eds. ), Elsever, 1995

Lectures, oral presentations, etc.

  • Development of Mechanistic Prediction Method of DNB Heat Flux Based on Two-Phase Flow CFD (6) Experiment of subcooled flow boiling
    Yue Wang; Yudai Tsutsui; Tomio Okawa
    Oral presentation, English, 日本原子力学会2025年春の年会
    14 Mar. 2025
    12 Mar. 2025- 14 Mar. 2025
    共同研究・競争的資金等URL
  • 流下液膜内核沸騰に起因する液滴飛散開始条件に関する実験的検討
    名手 海人; ラカ フィルマン; 成島 勇気; 大川 富雄; 上遠野 健一
    Oral presentation, Japanese, 日本原子力学会2025年春の年会
    14 Mar. 2025
    12 Mar. 2025- 14 Mar. 2025
    共同研究・競争的資金等URL
  • 二相流CFDに基づく機構論的DNB予測手法の開発 (9) 二相流CFDによるサブクール流動沸騰時のボイド率分布解析
    小瀬 裕男; 大川 富雄
    Oral presentation, Japanese, 日本原子力学会2025年春の年会
    14 Mar. 2025
    12 Mar. 2025- 14 Mar. 2025
    共同研究・競争的資金等URL
  • 二相流CFDに基づく機構論的DNB予測手法の開発 (8) 強制対流沸騰下における大気泡形成予測解析
    小野 綾子; 大川 富雄
    Oral presentation, Japanese, 日本原子力学会2025年春の年会
    14 Mar. 2025
    12 Mar. 2025- 14 Mar. 2025
    共同研究・競争的資金等URL
  • 二相流CFDに基づく機構論的DNB予測手法の開発 (5) 2024年度の主要成果の概要
    大川 富雄
    Oral presentation, 日本原子力学会2025年春の年会
    14 Mar. 2025
    12 Mar. 2025- 14 Mar. 2025
    共同研究・競争的資金等URL
  • Measurement of the liquid sublayer thickness during onset of DNB
    Thanh-Binh Nguyen; Akira Satou; Yasuteru Sibamoto; Tomio Okawa
    Oral presentation, English, 日本原子力学会2025年春の年会
    13 Mar. 2025
    12 Mar. 2025- 14 Mar. 2025
  • An Experimental Study of Rapid Cooling of High-Temperature Bodies Coated with Nanoparticle Layers
    SOM ONN OUCH; TOMIO OKAWA
    Oral presentation, English, 日本原子力学会2025年春の年会
    13 Mar. 2025
    12 Mar. 2025- 14 Mar. 2025
  • 気液二相流を用いた高効率冷却手法の開発
    泉川 誠人; 大川 富雄; 小泉 安郎; 西中 一貴; 古屋 歩
    Oral presentation, Japanese, 日本機械学会関東学生会第64回学生員卒業研究発表講演会
    03 Mar. 2025
    03 Mar. 2025- 03 Mar. 2025
    共同研究・競争的資金等URL
  • 強制対流サブクール沸騰のOSV発生に対する旋回流の影響
    筒井 雄大; 王 越; 大川 富雄
    Oral presentation, Japanese, 日本機械学会関東学生会第64回学生員卒業研究発表講演会
    03 Mar. 2025
    03 Mar. 2025- 03 Mar. 2025
  • ナノ流体が飽和プール沸騰の限界熱流束へ及ぼす影響
    道願陸斗; 柳田大智; 小泉安郎; 大川富雄
    Oral presentation, Japanese, 日本機械学会関東学生会第64回学生員卒業研究発表講演会
    2025
    03 Mar. 2025- 03 Mar. 2025
  • ナノ粒子層付きの焼結金属をウィックとするヒートパイプの伝熱 性能に関する研究
    王 萌蕾; 守 裕也; 大川 富雄
    Oral presentation, Japanese, 日本機械学会熱工学コンファレンス2024
    06 Oct. 2024
    05 Oct. 2024- 06 Oct. 2024
  • 液膜底層ドライアウトモデルに基づくDNB モデルの実験検証
    大川 富雄; グエン タン・ビン
    Oral presentation, Japanese, 日本機械学会熱工学コンファレンス2024
    05 Oct. 2024
    05 Oct. 2024- 06 Oct. 2024
  • 流下液膜内核沸騰による液滴飛散率予測手法の開発
    名手 海人; ラカ フィルマン; 成島 勇気; 大川 富雄; 上遠野 健一
    Oral presentation, Japanese, 日本原子力学会2024年秋の大会
    12 Sep. 2024
    11 Sep. 2024- 13 Sep. 2024
  • 強制対流サブクール沸騰中における薄液膜厚さの計測
    大川 富雄; Nguyen Thanh-Binh
    Oral presentation, Japanese, 日本原子力学会2024年秋の大会
    12 Sep. 2024
    11 Sep. 2024- 13 Sep. 2024
  • 高温固体面のクエンチ特性に及ぼす冷却液温度及び固体壁熱物性の影響
    梅林 宏行; 大川 富雄
    Oral presentation, Japanese, 日本原子力学会2024年秋の大会
    12 Sep. 2024
    11 Sep. 2024- 13 Sep. 2024
  • 液体ナトリウム噴流の分裂特性に関する数値シミュレーション
    孫 国富; 山下 晋; 大川 富雄; 吉田 啓之
    Oral presentation, Japanese, 日本原子力学会2024年秋の大会
    11 Sep. 2024
    11 Sep. 2024- 13 Sep. 2024
  • 液滴・液膜衝突現象におけるクラウンの生成と重力に関する数値解析
    白方 嵩晃; 大川 富雄; 山下 晋
    Oral presentation, Japanese, 日本機械学会2024年度年次大会
    09 Sep. 2024
    08 Sep. 2024- 11 Sep. 2024
  • Experimentation and Modeling of Subcooled Flow Boiling from the Perspective of Large Bubble Formation
    Tomio Okawa; Thanh-Binh Nguyen; Ryoma Tsujimura
    Oral presentation, English, 14th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety, Peer-reviewed
    27 Aug. 2024
    25 Aug. 2024- 28 Aug. 2024
  • Flow boiling CHF (the liquid film dryout and the departure from nucleate boiling)
    Tomio Okawa
    Public discourse, English, Tianjin University: Summer Lecture on Heat Transfer, Invited
    18 Aug. 2024
    16 Aug. 2024- 18 Aug. 2024
  • The Effect of Liquid and Wall Properties Toward the Increase of Wetting Velocity in the Case of Using Multiple Plates in the Top-Reflood Vertical Surfaces
    Akbari; Hiroyuki Umebayashi; Tomio Okawa
    Oral presentation, English, 31st International Conference on Nuclear Engineering, Peer-reviewed
    06 Aug. 2024
    04 Aug. 2024- 08 Aug. 2024
  • The Robust Development of a Thermal Hydraulic Analysis Method for Condensation Bubbles in Subcooled Flow Boiling Using AI Based Object Detection and Tracking Technique
    Wen Zhou; Shuichiro Miwa; Koji Okamoto; Tomio Okawa; Ryoma Tsujimura; Thanh-Binh Nguyen
    Oral presentation, English, 31st International Conference on Nuclear Engineering, Peer-reviewed
    05 Aug. 2024
    04 Aug. 2024- 08 Aug. 2024
  • 液膜内核沸騰における液滴飛散率の評価
    名手 海人; Raka Firman; 大川 富雄; 成島 勇気; 古市 肇; 上遠野 健一
    Oral presentation, Japanese, 第28回動力・エネルギー技術シンポジウム
    18 Jun. 2024
    17 Jun. 2024- 18 Jun. 2024
  • 4 複数のプレートを使用した場合の濡れ速度の増加に対する液体と壁の特性の影響
    Akbari Akbari; 梅林宏行; 大川富雄
    Oral presentation, English, 第28回動力・エネルギー技術シンポジウム
    18 Jun. 2024
    17 Jun. 2024- 18 Jun. 2024
    共同研究・競争的資金等URL
  • 飽和プール沸騰の限界熱流束に及ぼす加熱壁内熱伝導の影響
    柳田大智; 大川富雄; 小泉安郎
    Oral presentation, Japanese, 第28回動力・エネルギー技術シンポジウム
    17 Jun. 2024
    17 Jun. 2024- 18 Jun. 2024
  • 強制対流サブクール沸騰中の気泡⽣成頻度に及ぼす発泡核間⼲渉の影響
    大川富雄; 辻村玲摩
    Oral presentation, Japanese, 第61回日本伝熱シンポジウム
    29 May 2024
    29 May 2024- 31 May 2024
    共同研究・競争的資金等URL
  • Development an IVR System with Honeycomb Cooling Technology that combines CHF Improvement and Rapid Cooling of High-Temperature Bodies (3) Elucidation of Rapid Cooling Mechanism of High-Temperature Bodies by Nanofluids
    Som Onn Ouch; Tomio Okawa
    Oral presentation, English, 日本原子力学会2024年春の年会
    27 Mar. 2024
    26 Mar. 2024- 28 Mar. 2024
    共同研究・競争的資金等URL
  • Modeling and experimental validation for the relation between large bubble formation and departure from nucleate boiling
    Binh Thanh Nguyen; Ryoma Tsujimura; Tomio Okawa
    Oral presentation, English, 日本原子力学会2024年春の年会
    26 Mar. 2024
    26 Mar. 2024- 28 Mar. 2024
    共同研究・競争的資金等URL
  • 二相流CFDに基づく機構論的DNB予測手法の開発 (4)二相流CFDによるボイド率分布解析
    小瀬裕男; 大川富雄
    Oral presentation, Japanese, 日本原子力学会2024年春の年会
    26 Mar. 2024
    26 Mar. 2024- 28 Mar. 2024
    共同研究・競争的資金等URL
  • 二相流CFDに基づく機構論的DNB予測手法の開発 (3)強制対流沸騰下における大気泡生成モデルの構築
    小野綾子; 大川富雄; 吉田啓之
    Oral presentation, Japanese, 日本原子力学会2024年春の年会
    26 Mar. 2024
    26 Mar. 2024- 28 Mar. 2024
    共同研究・競争的資金等URL
  • 二相流CFDに基づく機構論的DNB予測手法の開発 (1)全体概要と流動沸騰実験
    大川富雄; Nguyen Thanh-Binh; 辻村玲摩
    Oral presentation, Japanese, 日本原子力学会2024年春の年会
    26 Mar. 2024
    26 Mar. 2024- 28 Mar. 2024
    共同研究・競争的資金等URL
  • 急収縮ノズルから流出する液噴流の流動特性に関する研究
    孫国富; 大川富雄; 青柳光裕; 内堀昭寛; 岡野 靖
    Oral presentation, Japanese, 日本原子力学会2024年春の年会
    26 Mar. 2024
    26 Mar. 2024- 28 Mar. 2024
  • 液膜内核沸騰における液滴飛散割合の評価
    名手海人; Raka Firman; 大川富雄; 成島勇気; 古市肇; 上遠野健一
    Oral presentation, Japanese, 日本機械学会関東学生会第63回学生員卒業研究発表講演会
    13 Mar. 2024
    13 Mar. 2024- 13 Mar. 2024
  • 液滴・液膜衝突時に生じる二次液滴の性質
    桒原悠人; 大川富雄; 白方嵩晃
    Oral presentation, Japanese, 日本機械学会関東学生会第63回学生員卒業研究発表講演会
    13 Mar. 2024
    13 Mar. 2024- 13 Mar. 2024
  • 鉛直矩形管における気相混入による二相流熱伝達促進
    古屋歩; 木村優佑; 小泉安郎; 大川富雄; 西中一貴
    Oral presentation, Japanese, 日本機械学会関東学生会第63回学生員卒業研究発表講演会
    13 Mar. 2024
    13 Mar. 2024- 13 Mar. 2024
  • 二相流CFDに基づく機構論的DNB予測手法の開発
    大川富雄
    Poster presentation, Japanese, NEXIP交流会, Invited
    26 Dec. 2023
  • 強制対流サブクール沸騰中におけるOSV及びDNBメカニズムの新解釈
    大川 富雄
    Invited oral presentation, 第26.0回相変化界面研究会, Invited
    21 Dec. 2023
  • New interpretations of the OSV and DNB phenomena in subcooled flow boiling
    Tomio Okawa; Thanh Binh Nguyen; Ryoma Tsujimura
    Invited oral presentation, English, Beiyang Power Forum, Tianjin University, Invited
    27 Nov. 2023
  • ナノ粒子層をウィックとするヒートパイプの伝熱性能に及ぼす充填率と作動流体の影響
    王萌蕾; 劉依凡; 大川富雄
    Oral presentation, Japanese, 日本機械学会 熱工学コンファレンス2023
    14 Oct. 2023
  • 部門設立30周年記念出版 Vol.1 動力エネルギー工学の基礎
    大川富雄
    Oral presentation, Japanese, 第27回動力・エネルギー技術シンポジウム
    21 Sep. 2023
  • A study of tube inclination and jacket plate effect on freeze plug performance in molten salt reactors
    Ilham Muhammad; Tomio Okawa
    Oral presentation, English, 日本原子力学会2023年秋の大会
    07 Sep. 2023
  • サブクールフローボイリングにおけるOsvの発生に及ぼす気泡の合体の役割
    グエン タイン ビン; 大川富雄; 辻村玲摩
    Oral presentation, English, 日本原子力学会2023年秋の大会
    07 Sep. 2023
  • Integration of AI Technology and Thermal Hydraulics for the Development of a Data-Driven Methodology for Plant Safety Assessment (3) Robust condensation bubble feature extraction in subcooled flow boiling using object detection and tracking technique
    Wen Zhou; Shuichiro Miwa; Tomio Okawa
    Oral presentation, English, 日本原子力学会2023年秋の大会
    07 Sep. 2023
  • 人工知能技術と熱流動の融合によるデータ駆動型プラント安全評価手法の開発 (2) 強制対流サブクール沸騰における発泡核間干渉とAI画像解析の応用
    辻村玲摩; グエンビン; 大川富雄; 周文; 三輪修一郎
    Oral presentation, Japanese, 日本原子力学会2023年秋の大会
    07 Sep. 2023
  • 急収縮ノズルから流出する液噴流の流動様式と分裂挙動に関する研究
    孫国富; 大川富雄; 青柳光裕; 内堀昭寛; 岡野靖
    Oral presentation, Japanese, 日本原子力学会2023年秋の大会
    06 Sep. 2023
  • Study on the effect of air flowrate and subcooled degree on boiling entrainment rate from a liquid film flowing downwards on a vertically heated surface
    Raka Firman; Baskara Permana; Tomio Okawa; Nade Kaito; Yuki Narushima; Kenichi Katono; Hajime Furuichi
    Oral presentation, English, 日本原子力学会2023年秋の大会
    06 Sep. 2023
  • Comparison of quench speeds of 1 and 2 cooling surfaces using metal plates
    アクバリ; 大川富雄
    Oral presentation, English, 日本機械学会2023年度年次大会
    04 Sep. 2023
  • グローバル気泡合体機構モデルに基づく大型気 泡の形成と有意なボイドの発生との相関性
    グエン タイン ビン; 大川富雄; 辻村玲摩
    Oral presentation, English, 日本機械学会2023年度年次大会
    04 Sep. 2023
  • ナノ粒子層によるヒートパイプの伝熱性能の改善
    王萌蕾; 劉依凡; 大川富雄
    Oral presentation, Japanese, 日本機械学会2023年度年次大会
    04 Sep. 2023
  • 液滴・液膜衝突時の二次液滴生成特性
    大川富雄; 白方嵩晃; 桑原悠人
    Oral presentation, Japanese, 混相流シンポジウム2023
    26 Aug. 2023
  • G221 ナノ粒子層をウィックとするヒートパイプの伝熱性能に及ぼす充填率の影響
    王萌蕾; 劉依凡; 大川富雄
    Oral presentation, Japanese, 第60回日本伝熱シンポジウム
    26 May 2023
  • Measurement of Boiling Entrainment Rate from a Liquid Film Flowing Downwards on a Vertical Heated Surface
    Raka Firman; Baskara Permana; Tomio Okawa; Yuki Narushima; Hajime Furuichi; Kenichi Katono
    Oral presentation, English, 日本原子力学会春の年会
    14 Mar. 2023
  • プール沸騰の限界熱流束に及ぼす伝熱面内熱拡散の影響
    柳田 大智; 大川 富雄; 小泉 安郎
    Oral presentation, Japanese, 日本原子力学会春の年会
    14 Mar. 2023
  • 長円形ノズルから流出する液噴流の分裂と液滴スプラッシュに関する研究
    孫 国富; 詹 翼; 大川 富雄; 青柳 光裕; 内堀 昭寛; 岡野 靖
    Oral presentation, 日本原子力学会春の年会
    14 Mar. 2023
  • Experiment on boiling entrainment from a falling liquid film
    T. Okawa, J. Tabuchi, R. Firman, Y. Narushima, H. Furuichi, and K. Katono
    Invited oral presentation, English, 1st European-American-Japanese Two-Phase Flow Group Meeting, Invited, International conference
    25 Oct. 2022
  • ナノ流体によるヒートパイプの伝熱性能の改善
    王萌蕾, 大川富雄
    Oral presentation, Japanese, 熱工学コンファレンス
    08 Oct. 2022
  • 強制対流サブクール沸騰における発泡核間の干渉が気泡の発泡頻度に与える影響
    辻村玲摩, 大川富雄, グエン・ビン
    Oral presentation, Japanese, 熱工学コンファレンス
    08 Oct. 2022
  • Measurement of Bubbly Layer Void Fraction at the Point of Onset of Significant Void in Subcooled Flow Boiling
    Binh Thanh Nguyen, Tomio OKAWA, Ryoma TSUJIMURA
    Oral presentation, English, 日本原子力学会「2022年秋の大会」
    08 Sep. 2022
  • 長円形ノズルから流出する液噴流の分裂挙動に関する研究
    孫国富、詹翼、大川富雄、青柳光裕、内堀昭寛、岡野靖
    Oral presentation, Japanese, 日本原子力学会「2022年秋の大会」
    08 Sep. 2022
  • プール沸騰CHFに及ぼす伝熱面材質の影響
    大川富雄, 中濃昂輝, 小泉安郎, 柳田大智, Feng Yan
    Oral presentation, Japanese, 第26回動力・エネルギー技術シンポジウム
    14 Jul. 2022
  • シリカゾルにおけるヒートパイプへの応用及び伝熱性能の影響
    劉依凡, Wang Menglei, 梅原裕太郎, 大川富雄, 清水大輔
    Oral presentation, Japanese, 第26回動力・エネルギー技術シンポジウム
    14 Jul. 2022
  • ナノ流体によるナノ粒子層をウィックとするヒートパイプの伝熱 性能の改善
    王萌蕾、大川富雄
    Oral presentation, Japanese, 第59回日本伝熱シンポジウム
    20 May 2022
  • A New Mechanistic Model for Prediction of the Departure from Nucleate Boiling Heat Flux
    Thanh Binh NGUYEN, Tomio OKAWA
    Oral presentation, English, 第59回日本伝熱シンポジウム
    18 May 2022
  • POSSIBLE ROLE OF BUBBLE COALESCENCE IN CAUSING OSV AND DNB IN SUBCOOLED FLOW BOILING
    Tomio Okawa and Nguyen Thanh Binh
    Keynote oral presentation, English, Japan-U.S. Seminar on Two-Phase Flow Dynamics, Invited, International conference
    11 May 2022
  • ON SPLASHING DURING DROP IMPACT ONTO A QUIESCENT LIQUID FILM
    Tomio Okawa
    Keynote oral presentation, English, 32nd International Symposium on Transport Phenomena, Invited, International conference
    21 Mar. 2022
  • 現象論的クエンチモデルの開発及び適用性の検討
    梅原裕太郎, 大川富雄
    Oral presentation, Japanese, 日本原子力学会「2022年春の年会」
    17 Mar. 2022
  • Experimental Study on Onset Condition of Boiling Entrainment from Falling Liquid Film with Gas Sheared Flow
    Raka Firman, Junpei Tabuchi, Tomio Okawa, Yuki Narushima, Hajime Furuichi, Kenichi Katono
    Oral presentation, English, 日本原子力学会「2022年春の年会」
    17 Mar. 2022

Courses

  • インフォパワード・エネルギー概論
    2024 - Present
  • Physics Ⅱ
    2021 - Present
  • 熱工学基礎
    2021 - Present
  • 熱力学応用
    2021 - Present
  • 熱力学
    2021 - Present

Affiliated academic society

  • 日本伝熱学会
  • 日本原子力学会
  • 日本機械学会
  • 日本混相流学会

Works

  • 広範囲の燃料格子仕様に適用する汎用沸騰遷移解析手法に関する技術開発
    2004
  • 気液界面相互作用モデルに関する研究
    2001
  • A study on analytical models for phase interface
    2001
  • オイラー・ラグランジェモデルを用いた分散性気液二相流数値解析に関する研究
    2000
  • A study on numerical simulation of dispersed two-phase flow using Euler-Lagrange model
    2000

Research Themes

  • 超高温体の急冷機能を付与したハニカム冷却技術による新型原子炉のIVR開発
    文部科学省, 原子力システム研究開発事業, 九州大学; 電気通信大学, Coinvestigator
    Sep. 2023 - Mar. 2026
  • 二相流CFDに基づく機構論的DNB予測手法の開発
    文部科学省, 原子力システム研究開発事業, 電気通信大学; 九州大学; 日本原子力研究開発機構; 大和システムエンジニア, Principal investigator
    Sep. 2023 - Mar. 2026
  • ナノ粒子層と旋回流を併用する超高熱流束除熱技術の開発 補助事業
    公益財団法人JKA, Principal investigator, 2023M-387
    Apr. 2023 - Mar. 2025
  • 高温壁の液膜冷却時におけるクエンチ速度予測モデルの高度化
    中部電力株式会社, Principal investigator
    Apr. 2023 - Mar. 2025
  • Development of mechanistic CHF model in subcooled flow boiling
    大川 富雄
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), 強制対流サブクール沸騰における限界熱流束(CHF)の機構論的予測では、小気泡の合体により形成される大気泡と加熱壁の間に薄液膜が形成され、これが消失すると壁温の急上昇を開始すると仮定する。これをLiquid Sublayer Dryoutモデル（以下LSDモデルと称する）と呼び、広範囲の実験条件で得られたCHFデータをよく予測することが知られている。ここで、LSDモデルに基づくCHFの予測では、大気泡の長さLB、大気泡の上昇速度UB、薄液膜の厚さdの三つを適切に与える必要があるが、これらの物理量に関する実験情報は現状では皆無に近い。このため、既存のLSDモデルでは、まず開発者が適当と考える方法でLB,UB,dを評価した上でCHFを計算し、CHFの計算結果を実験データと比較することでモデルの妥当性を検証している。この場合、CHFの計算値が実験データと一致していても、LB,UB,dの各々を正確に評価できている保証はない。この意味で、既存のLSDモデルは経験則の範疇を出ていない。したがって、通常の経験的相関式と同様に、モデル開発に用いた実験データベースの条件範囲外では、大幅な予測精度の低下を覚悟する必要がある。そこで本研究では、透明伝熱面、IRカメラ、高速度カメラ、レーザー変位計を用いた強制対流サブクール沸騰実験装置を構築するとともに実験データの収集作業を実施し、CHF状態に移行するときの熱流動状態がLSDモデルの想定と整合することを確認した。また、基本的な実験条件において、LSDモデルの根幹となる三つの物理量、すなわちLB,UB,dが計測可能であることを実証した。, 22K03940
    Apr. 2022 - Mar. 2025
  • 液噴流・液膜衝突時の液滴生成に関する研究
    日本原子力研究開発機構, 日本原子力研究開発機構, Principal investigator
    Apr. 2023 - Mar. 2024
  • Clarificaion of the relation between wetting front propagation velocity and pool boiling CHF
    小泉 安郎; 大川 富雄
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), Coinvestigator, 核沸騰による除熱は、きわめて高い熱伝達率を示す高効率の冷却手法であり、その応用が様々な分野で期待されている。ただし、限界熱流束（CHF）を超過すると、沸騰様式が膜沸騰に移行して、熱伝達率が大きく低下する。このため、より高いCHF値を示す高性能伝熱面の開発が、世界各所で精力的に行われている。本研究では、伝熱面の表面性状によってCHF値が大きく変化する主要因と考えられる因子として、各種伝熱面の濡れ進展速度を計測し、別途計測するプール沸騰CHFとの関係を調べる。得られた結果より、濡れ進展速度を主要変数とするCHF相関式を開発することを目的としている。本研究により、伝熱実験をせずとも、各種伝熱面のCHFを予測することが可能となるため、CHF向上化方策の方向性が明確となり、より高いCHFを示す高性能伝熱面の開発を、効率的に行うことが可能となると期待できる。本研究の初年度である令和3年度には、様々な伝熱面に対して、濡れ進展速度とCHFの計測を可能とするため、板状の伝熱面を設置可能な試験容器を製作するとともに、その下部に高強度のレーザー光を照射することで、沸騰開始から限界熱流束に至るまでの範囲で、沸騰曲線を得るための準備を整えた。また、通常の伝熱面を用いてプール沸騰実験を実施することにより、広く知られている核沸騰熱伝達相関式とよく一致する結果が得られることを確認した。これより、本実験装置により、十分に高精度の実験を実施可能であることを確認した。, 21K03895
    Apr. 2021 - Mar. 2024
  • Development of data-driven plant safety evaluation method by fusion of artificial intelligence technology and thermal hydraulics
    三輪修一郎
    文部科学省（東京大学からの再委託）, 原子力システム研究開発事業, 東京大学、日本原子力研究開発機構、株式会社原子力エンジニアリング, Coinvestigator
    2021 - 2023

Industrial Property Rights

  • ヒートパイプ製造方法
    Patent right, 大川 富雄, 王 萌蕾, 特願2019-085579, Date applied: 26 Jan. 2019, 国立大学法人電気通信大学, 特許第7284988号, Date registered: 24 May 2023
  • シリンジポンプ装置
    Patent right, 榎木光治, 宮田一司, 秋澤淳, 大川富雄, 特願2017-072214, Date applied: Mar. 2017, 特開2018-173038, Date announced: Nov. 2018, 特許第6899132号, Date registered: 16 Jun. 2021
  • フリーズバルブ、原子炉、および太陽熱発電装置
    Patent right, 大川富雄, インダルタ・クンコロ・アジ, 木下幹康, 吉岡律夫, 特願2019-092316, Date applied: 2019
  • ボイラ
    Patent right, 大川富雄, 榎木光治, 特願2016-242453, Date applied: Dec. 2012, 特開2018-96631, Date announced: Jun. 2018
  • 冷却剤
    Patent right, 大川 富雄, 梅原 裕太郎, 榎木 光治, 特願2018-044725, Date applied: Mar. 2018
  • 冷却剤、冷却装置および冷却方法
    Patent right, 大川 富雄, 梅原 裕太郎, 榎木 光治, 特願2017-046260, Date applied: Mar. 2017
  • 気液二相流シミュレーションの計算方法、プログラム、および装置
    Patent right, 大川富雄, 杉中隆史, 湊明彦, 特願2012-149590, Date applied: Jul. 2012, 特開2014-013424, Date announced: 23 Jan. 2014
  • 逆熱対流混相流体
    Patent right, 片岡勲、他5名, 特願2000-69510, Date applied: 2000, 特開2001-262133, Date announced: 2001