Natural Convective Heat Transfer in Rectangular Enclosures with a Cold Source

具冷源之矩形封閉空間自然對流熱傳遞

蔡瑞益(R. Tsai) ； 陳冠宇(K. Y. Chen) ； 梁龍驥(L. J. Liang)

《中原學報》 29卷1期 (2001/03) Pp. 63-68

https://doi.org/10.6358/JCYU.200103.0063

摘要

本文研究具冷源之二維矩形封閉空間内自然對流熱傳遞現象，其流場和溫度場之動量與能量方程式以PHOENICS CFD套裝軟體之Κ-ε紊流模型結合壁函數計算；另冷源側之邊界值條件以較低溫度設定，另外三面高溫側則設定總熱傳遞系數為常數，所得的結果包括不同長寬比之速度分佈與溫度分佈，及紐雪爾數與修正雷萊數之關係式。其關係式為（平均值）Nu=0.141Ra^0.212(AR)^0.362(hW/k(下标 f))^0.343其中1×10^9≤Ra≤1×10^11，1.0≤AR≤2.0，與1W/m^2K≤h≤10W/m^2K。

關鍵字

自然對流 ； 紐雪爾常數 ； 修正的雷萊數

並列摘要

A study of natural convective heat transfer in a two-dimensional rectangular enclosure with a cold source is reported. PHOENICS CFD software package is used to solve the conservation of momentum equation and energy equation by using Κ-ε turbulence model associated with wall functions. The cold source side is taken as the low temperature, whereas the overall heat transfer coefficient to be constant is taken as the high temperature boundary condition at the other three sides. The results include the distributions of flow velocity and temperature in the enclosure under different aspect ratios, and a correlation of the relationship of mean Nusselt number and modified Rayleigh number. When 1×10^9≤Ra≤1×l0^11,1.0≤AR≤2.0 and 1W/m^2K≤h≤10W/m^2K, the relation is (average)Nu=0.141Ra^0.212(AR)^0.362(hW/k(subscript f))^0.343.

並列關鍵字

natural convection ； Nusselt number ； modified ； Rayleigh number