本文係以數值模擬進行水平風道內底部加熱的多孔性方柱之暫態流場與熱傳研究，具有多孔性介質區域內的統御方程式將採用暫態的Darcy-Brinkman-Forchheimer模式及能量方程式進行求解。此數值模擬是使用半隱性投射有限元素法，研究的參數包含孔隙率、達西數、雷諾數、格拉氏數及多孔性方柱高度與風道高度比，而這些參數對於流場及熱傳的效應已經被詳細探討。結果顯示達西數增加時，平均局部紐賽數將會增加。雷諾數增加時，平均局部紐賽數也會增加，特別是搭配高達西數時，其增加的幅度會更顯著；相比較下孔隙率對於熱傳的影響很小。而多孔性方柱高度與風道高度比增加時，熱傳效果也會增加。由局部紐賽數計算結果得知，B/H=0.1的時候浮力效應比B/H=0.3與B/H=0.5明顯。

A numerical study is made of the unsteady flow and convection heat transfer for a square porous cylinder with the heated cylinder bottom in a horizontal channel. The governing equations with the unsteady Darcy-Brinkman- Forcheimer model and energy equation for the region of square porous cylinder were solved. A semi-implicit projection finite element method in this work is used. The parameters studies include porosity, Darcy number, Reynolds number, Grashof number, and channel-to-cylinder height ratio and how they affect flow field and heat transfer performance have been explored in detail. The results indicate that the average local Nusselt number is augmented as the Darcy number increases. The average local Nusselt number increases as Reynolds number increases; in particular, the increase is more obvious at a higher Darcy number. In contrast, the porosity has slight influence on heat transfer. The heat transfer is augmented as the Darcy number and channel-to-cylinder height ratio increase. The buoyancy effect on the local Nusselt number is more clear for B/H = 0.1 than for B/H = 0.3 and B/H = 0.5.

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