2022 Fiscal Year Final Research Report
Sophisticated modeling for quenching of a hot surface with a multi-time scale transient heat transfer model
Project/Area Number |
20K04314
|
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 | Saga University |
Principal Investigator |
|
Project Period (FY) |
2020-04-01 – 2023-03-31
|
Keywords | 非定常遷移沸騰伝熱 / 高温面のぬれ / ウエッティングフロント / 衝突噴流冷却 / 非定常熱伝導 |
Outline of Final Research Achievements |
A technique has been proposed to determine the boundaries of coexisting multiple heat transfer modes, single-phase forced convection, nucleate boiling, and transition boiling on a hot surface during subcooled impinging jet quenching. Existing heat transfer correlations for single-phase forced convection and nucleate boiling are found to apply to non-uniform and unsteady surface temperature surfaces. From the highspeed visual observation, the transition boiling is characterized by advancing and receding wetting front in sync with the period of the disturbance wave. The time-averaged heat transfer rate in transition boiling was evaluated with the analytical solution of transient heat conduction in solid-liquid contact. Coupling analysis of axisymmetric unsteady heat conduction of a hot surface with the coexisting heat transfer modes provides a better understanding of the behavior of the stable wetting during quenching.
|
Free Research Field |
熱工学
|
Academic Significance and Societal Importance of the Research Achievements |
遷移沸騰領域の伝熱過程は,不安定な固液接触に伴う固体側の非定常熱伝導と連成した非定常性の強い伝熱過程であり,一義的に熱伝達率あるいは熱流束を与えるのが困難であった.本研究では,高温面衝突噴流冷却時の安定なぬれ面の先端部のWetting Front(WF)と呼ばれる三相境界線の前進と後退が噴流界面の不安定波長周期に支配されるという観測結果に基づいた遷移沸騰熱流束の評価法を提案した.遷移沸騰領域の伝熱モデルを組み込んだ高温面の非定常熱伝導計算は,実験でのWFの時間挙動を非常によく再現できることを示した.本研究成果は,今後材料製造プロセスの冷却温度制御の精度向上への寄与が期待される.
|