本研究針對自然對流下，圓柱熱源周圍佈置平板矩形鰭片之散熱效能進行深入探討，使用三維逆向計算流體力學方法結合最小平方法及多點實驗溫度數據來預測整體系統與單一鰭片之熱傳特性。為因應小型電子設備在受限空間中之自然對流散熱挑戰，透過CFD數值模擬與實驗數據比較，分析不同幾何變因對熱傳效益的影響。
本文採用RANS法流動模型與逆向方法，對零方程式模型、Standard k -ε流動模型與RNG k -ε模型的測試發現，零方程式模型不論是在上開口邊界或是煙囪式邊界，皆具有較小的均方根誤差值，分別為0.79K與1.46K，且鰭片平均熱對流係數預測值也最接近參考數據，因此零方程式模型為最適用本文的模型。
研究中考量兩種開口邊界（上開口與煙囪式），配合不同鰭片數量與鰭片高度，共24組變因進行模擬。結果顯示，鰭片熱傳效率受鰭片高度與鰭片數量顯著影響，最高與最低鰭片效率差異超過41%；系統總熱阻在鰭片高度增加時有明顯下降趨勢，最大值為最小值的近三倍。此外，根據模擬結果與實驗數據比對結果，進一步提出修正型經驗公式，以提升自然對流鰭片式散熱設計之預測準確性與實用性。最後，本文總結各項變因之影響並提出未來研究之建議與展望。

This study investigates the heat dissipation performance of flat rectangular fins arranged around a cylindrical heat source under natural convection. A three-dimensional inverse computational fluid dynamics (CFD) method, combined with the least squares method (LSM) and multi-point experimental temperature data, is used to predict the heat transfer characteristics of both the overall system and individual fins. To address cooling challenges in compact electronic devices, CFD simulations and experimental results are compared to evaluate the effects of fin height, fin number, and two boundary conditions (top-open and chimney-type), resulting in 24 cases. The results show that the zero-equation model yields the smallest root mean square errors (0.79 K and 1.46 K) and predicts fin average heat convection coefficients closest to reference data, making it the most suitable model. Increasing fin height significantly reduces total thermal resistance—by up to a factor of three between the maximum and minimum values—while fin efficiency differences exceed 41%. A revised empirical correlation is proposed to enhance prediction accuracy and practical applicability in natural convection finned heat sink design.

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