本文以有限差分法、最小平方法之逆算法搭配實驗溫度量測值來估算俱有縱向鰭片之垂直式圓柱熱沉在不同鰭片條件下，置放於上開口與上下開口之煙囪式外殼內之熱傳係數，由於鰭片之熱傳係數並非均勻分佈，故進行逆運算前，須將鰭片分割為多個小區域，而後把熱電偶安裝於各小區域上以量測不同條件下之量測位置溫度。並以商用軟體FLUENT搭配各種流動模式及適當格點數目模擬求取各量測點之溫度、熱傳係數，探討鰭片間之空氣溫度與流場速度分佈情形。比較各種流動模式所求得之數值結果，以探討其差異性，尋求與實驗溫度量測相近之結果。結果顯示，流動模式及網格點數目對數值結果之影響不容忽視。邊界條件方面，若將鰭片置於煙囪式邊界之盒子內，會因煙囪效應而增加自然對流效果。而圓柱熱沉的總散熱量會隨著鰭片數量的增加而提升，但鰭片上的平均熱傳係數卻因此而下降。此外鰭片長度亦對散熱有很大的影響，長度越長總散熱量越高、平均熱傳係數越低，並有逐漸趨緩的現象。為了驗證所得結果之可靠性及可用性，所求得熱傳係數之逆算結果與其他相關文獻之經驗式相比較，並與以改良修正，以獲得更加精準的經驗公式。

In this study, inverse method and FLUENT are applied to determine the heat transfer and fluid flow characteristics of vertical cylinder heat sinks with longitudinal fins in the cabinet with two kinds of boundary conditions, upward-opening & chimney. Inverse method indicating finite difference method, and least square method is a simple but prompt way to predict the heat performance. In order to using inverse method, the temperature on the fin should be measured, so thermocouples are installed on the fin, which is apart into several small regions, and measure the temperature of these places Inverting the measured data to predict the average heat transfer coefficient, heat transfer rate, and also conjugate with FLUENT to choose the correct simulation setting, including flow model, and grid setting. Through the simulation, the correct temperature field, and flow field could be visible. The results show that the heat transfer coefficient decrease as the number of fins, or the height of fins increase. Besides, heat transfer performance improved significantly as the boundary condition of cabinet from upward-opening to chimney. This change makes more fluid participate in heat dissipation to exchange heat more efficiently. Finally, in order to verify the reliability of predicted results of this paper, the present study also compared with the empirical correlations of other relevant literature. Moreover, the empirical correlation is revised to become more accurate and wide-ranged.

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