Transient Natural convection heat transfer of micropolar fluids between inner sphere and outer vertical cylinder

微極流體在內球體與外垂直圓柱體間之暫態自然對流熱傳遞

Wen Ruey Chen(陳玟瑞)

《冷凍空調&能源科技》 108期 (2018/03) Pp. 53-59

摘要

The effect of micropoar parameter in a complex annulus filled with micropolar fluids have been investigated numerically to determine heat transfer characteristics and flow structure micromotions between the inner sphere and outer vertical cylinder with specified isothermal boundary conditions. Computations were carried out systematically for the several different parameters of geometric ratio, Rayleigh number and material parameters of micropolar fluid to determine the average Nusselt number and the skin friction coefficient on the flow and the thermal fields. The material parameters are dimensionless spin gradient viscosityλ, dimensionless micro-inertia density B and dimensionless vortex viscosity F. The governing equations, in terms of vorticity, stream function, angular momentum and temperature are expressed in a spherical polar coordinate system. Results were presented some physical phenomenon in a complex annulus. Comparisons are attempted between the Newtonian fluid and micropolar fluid.

關鍵字

micropolar fluids ； complex annulus ； isothermal boundary conditions

並列摘要

數值模擬解出複合環型填充微極流體之微極參數效應，並完成探討等溫邊界條件介於內球與外垂直圓柱間之熱傳特性和微流埸運動結構。針對有系統化的幾個不同參數為幾何比、萊利數及微極流體材料參數下已完模擬計算解出在熱流埸的平均紐賽數、表面摩擦係數。材料參數分別為無因次化旋梯黏滯度，λ、微貫性密度，B和渦旋黏滯度，F等。控制方程式分別為渦旋、流線函數、角動量和能量方程式在球極座標系統表示之。其結果在複合環型參數下獲得一些物理現象。其結果與牛頓流體比較。

並列關鍵字

微極流體 ； 複合環型 ； 等溫邊界條件