Study of thermofluid phenomena in phase change materials using simultaneous visualization of temperature, velocity, and heat transfer coefficient

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K14658
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 19020:Thermal engineering-related
• Research Institution: Hirosaki University
• Principal Investigator: Okabe Takahiro 弘前大学, 理工学研究科, 准教授 (70772713)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 相変化材料 / 赤外線サーモグラフィ / 2色レーザー誘起蛍光法 / 粒子画像流速測定法 / レイリーベナール対流 / 可視化計測

Outline of Final Research Achievements

In this study, we investigated a natural convection on melting process of phase change materials using a simultaneous visualization of temperature, velocity, and heat transfer coefficient. We clarified that the heat transfer mechanism varies continuously based on melting stages of the phase change material, and it is considerably affected by the variations in the Stefan number and inclination angle. In addition, we obtained the scaling law of the Nusselt number and the Rayleigh number for each condition and found to be different values of the Nusselt number depending on the tested conditions.These variations were attributed to the changes in the number of ascending and descending plumes, solid-liquid interface, convection structure, and supply of cold fluid at each melting stage. Our experimental results can be used to enhance the understanding of the relevant phenomena and validate numerical simulations related to the melting of phase change materials.

Free Research Field

熱工学

Academic Significance and Societal Importance of the Research Achievements

相変化材料の融解過程で生じるレイリーベナール対流の熱流動現象の理解は，近年注目を集める潜熱蓄熱システムの最適な熱設計に必要不可欠である．本研究で開発した温度・速度・加熱面熱伝達率の時空間同時計測手法は，既存技術では難しかった複雑な当該熱流動現象の詳細な評価を可能とし，最適熱設計に有用な多くの新たな学術的知見を提供した．さらに，本研究で得た同時可視化データは相変化材料の融解に関連する数値シミュレーションコードのベンチマークに有用である．