Double-Diffusive Natural Convection from a Vertical Cone in a Porous Medium Saturated with a Nanofluid

充滿奈米流體之多孔介質在垂直圓錐表面之雙擴散自然對流

鄭慶陽(Ching-Yang Cheng)

《中國機械工程學刊》 34卷5期 (2013/10) Pp. 401-409

摘要

本文研究充滿奈米流體的多孔介質在垂直圓錐表面之雙擴散自然對流，而此多孔介質承受均勻壁溫、均勻壁濃度與均勻壁奈米粒子容積分率。先導出相似方程式，再以三次樣線配置法求解。繪出不同重要參數值時之溫度曲線與奈米粒子容積分率曲線。並研究重要參數對局部紐塞爾數之影響。結果顯示，增大熱泳參數或布朗參數會降低局部紐塞爾數。而且增加奈米流體浮力比或奈米流體路易士數會減少局部紐塞爾數。而增加雙擴散浮力比或減少一般路易士數則會增大局部紐塞爾數。

並列摘要

This work studies the double-diffusive natural convection over a vertical cone embedded in a porous medium saturated by a nanofluid with constant wall temperature and concentration as well as constant wall nanoparticle volume fraction. Similarity equations are derived and then solved by the cubic spline collocation method. The temperature profile and the nanoparticle volume fraction profile are plotted for various values of important parameters. The effects of important parameters on the local Nusselt number have been studied. Results show that an increase in the thermophoresis parameter or the Brownian parameter tends to decrease the local Nusselt number. Moreover, the local Nusselt number decreases as the nanofluid buoyancy ratio or the nanofluid Lewis number is increased. Furthermore, an increase in the double-diffusive buoyancy ratio or a decrease in the regular Lewis number tends to increase the local Nusselt number.

並列關鍵字

natural convection ； double diffusion ； vertical cone ； nanofluid ； porous medium