| Project/Area Number |
18K03973
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 19020:Thermal engineering-related
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| Research Institution | The University of Electro-Communications |
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Principal Investigator |
Okawa Tomio 電気通信大学, 大学院情報理工学研究科, 教授 (20314362)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2018: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | クエンチ / リウェット / 熱伝達率分布 / IRカメラ / 無次元相関式 / クエンチング / クエンチ速度 / クエンチ温度 / 機構論的相関式 / 高温面冷却 / 濡れ開始温度 / 相関式 / 液膜進展速度 / 沸騰熱伝達 |
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| Outline of Final Research Achievements |
Spatial distribution of the heat transfer coefficient (HTC) in the vicinity of the wetting front is of crucial importance in predicting the wetting velocity during liquid film cooling of a high-temperature solid surface. However, mainly due to the lack of experimental data, no sufficiently reliable model has been developed so far for the HTC distribution in this fundamental thermal-hydraulic situation. In the present work, experiments using a high-speed infra-red camera were carried out to measure the transient of wall temperature distribution during wetting of a high-temperature vertical wall with a falling liquid film. Based on the HTC distributions calculated from the measured temperature data, dimensionless correlations were developed for the HTC distribution near the wetting front. It was confirmed that the propagation velocities of the wetting front (wetting velocity) calculated using the proposed correlations agree with the experimental data accumulated in this work well.
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| Academic Significance and Societal Importance of the Research Achievements |
高温固体の沸騰冷却（クエンチ）は、日本刀の焼き入れや鉄鋼材料の熱処理で見られる身近かつ重要な熱流動現象である。特に、原子力発電所で冷却材喪失事故が生じた場合、高温となった炉心に冷却水を注入して、燃料棒を再び濡らす（リウェット）させる必要がある。このため、クエンチあるいはリウェット時に、液体によって濡らされた領域が進展する速度（クエンチ速度）を予測することは、日本刀や鉄鋼材料の品質及び原子力発電所の安全性に関係する重要な技術である。本研究では、クエンチ速度予測の根幹となる熱伝達率分布データを世界で初めて計測することに成功し、熱伝達率分布データに基づく熱伝達率分布相関式を世界で初めて開発した。
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