Clarificaion of the relation between wetting front propagation velocity and pool boiling CHF

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03895
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 19020:Thermal engineering-related
• Research Institution: The University of Electro-Communications
• Principal Investigator: Koizumi Yasuo 電気通信大学, 大学院情報理工学研究科, 研究支援推進員 (20215156)
• Co-Investigator(Kenkyū-buntansha): 大川 富雄 電気通信大学, 大学院情報理工学研究科, 教授 (20314362)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: プール沸騰 / 限界熱流束 / CHF / 濡れ進展速度

Outline of Final Research Achievements

Pool boiling experiments were conducted using water as the test fluid to elucidate the relationship between the wetting propagation speed of the heat transfer surface and pool boiling CHF. Two types of surfaces were prepared to investigate the effect of surface properties: polished surface and oxide surface. The experimental results showed that the wetting propagation speed was 0.10 m/s for the polished surface and 0.12 m/s for the oxidized surface, indicating that the formation of the oxide film significantly changed the wetting propagation speed noticeably. From this, it was expected that CHF would improve on the oxidized surface, but the measured CHF was 806 kW/m2 for the polished surface and 791 kW/m2 for the oxidized surface. Therefore, it will be important in the future to study the relationship between wetting growth rate and CHF with more significant changes in both the parameters.

Free Research Field

熱工学

Academic Significance and Societal Importance of the Research Achievements

プール沸騰の限界熱流束(CHF)は、高発熱電子機器の冷却やエネルギー関連プラントの安全確保で工業的にきわめて重要な技術である。近年、加熱壁の表面に微細加工を施したり被膜を形成したりすると、CHFが有意に変化することが報告されているが、CHFに変化を生じるメカニズムは十分に明らかにされていない。本研究では、CHF変化の直接的な原因となりうる濡れ進展速度の実験計測に成功するとともに、これが酸化被膜の形成により有意に変化することを示した。したがって、本研究の成果は、プール沸騰CHF向上効果のメカニズム解明、及び高CHF伝熱面開発の効率化に寄与するものと言える。