本文主要針對在平板熱交換器中，多孔散熱片對壓力降和熱傳特性的影響作數值模擬，並與S. Y. Kim(2000)之實驗結果作比較。統御方程式乃是以控制體積法（Control Volume Approach）為基礎，配合有限差分法（Finite Difference Method）及冪次法則（Power Law Scheme）來離散成差分方程式；動量方程式的速度及壓力則以SIMPLE（Semi－Implicit Method for Pressure－Linked Equation）法來解出。至於格點設計方面，則採用正交，不等間距交錯式格點系統。
本文研究的參數為層流與紊流雷諾數（Re＝270~2050，5090~30540），多孔散熱片之孔隙率（ ＝0.89、0.92、0.94、0.96），孔密度（PPI＝10、20、40），工作流體為空氣。流場數值計算的結果顯示速度向量值的大小和方向會受到非達西效應的影響；而摩擦因子在低滲透率的多孔散熱片中是非常小的，乃是由於相對的表面積很大。可由所得到的數值導出多孔散熱片的摩擦因子關係式。
在熱傳效應方面，空氣流經多孔散熱片時，會隨著雷諾數的增加帶走更多的熱量。因熱對流效應增強，在紊流流場中無因次的紐賽數（Nusselt number）值會比層流流場高。多孔散熱片中的修正型j因子－j*會隨孔密度增加或孔隙率下降而下降，可由所得到的數值導出多孔散熱片的修正型j因子－j*的關係式。另外亦可發現多孔散熱片在孔密度PPI=40和 ＝0.89時置於平板熱交換器中會有較好的熱效益。

This study presents the numerical simulation of the impact of porous fin on the pressure drop and heat transfer characteristics in plate-fin heat exchangers compared the experimental data of S. Y. Kim(2000). The governing equations are solved by a Control-Volume-based finite-difference method with power-law scheme to describe the structure. The velocity and pressure terms of momentum equations are solved by SIMPLE（Semi－Implicit Method for Pressure－Linked Equation）method. An orthogonal non－uniform staggered grids are used for the establishment of mesh grids.
The parameters studied include the Reynolds number of laminar and turbulent flow （Re =270~2050，5090~30540）, the porosity of the porous fin（ ＝0.89、0.92、0.94、0.96）, and the pore density（PPI=10、20、40）, whereas the working medium is air. The numerical calculations of flow field indicate that non－Darcy effect has a significant effect on the prediction of the velocity vectors, and the friction factor is much lower for low permeable porous fins due to relatively larger surface area.
As to the heat transfer effect, air takes away more heat when it passes through the porous fins with increasing Reynolds number. Due to the enhancement of heat convection, the Nu of the turbulent flow is much higher than that of laminar flow. The modified j factor－j* of the porous fins decreases as the pore density increases or the porosity decreases. According to the numerical predictions, the correlation of modified j factor－j* for porous fins is provided as well as the friction factor. It is also found that the porous fins with low permeability and low porosity are preferable on thermal performance of plate－porous fin heat exchangers.

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