本文以實驗溫度及逆算法搭配三維CFD軟體得出穿孔環狀鰭管式熱交換器在矩形流道中，處於混合對流時的熱傳以及流場特性，並探討入口風速、穿孔位置及鰭片間距對上述特性之影響。空氣流經環狀鰭管式熱交換器時所產生之複雜流動行為，使得鰭片上的熱傳係數並非均勻分布，因此將鰭片劃分為多個子區域，使用實驗量測溫度結合有限差分法及最小平方法的逆算法預測鰭片之熱傳係數。本文亦利用CFD商用軟體進行數值模擬，求得溫度場、流場及熱傳係數後與實驗數據及逆算法結果比較，探討不同紊流模式及網格劃分之適用及可信度。結果顯示於模擬中選用RNG k-ε紊流模式較為符合實驗及逆算法結果與趨勢；隨著風速加快、間距增大會使熱傳係數提升；此外，於低速尾流區穿孔之鰭片與未穿孔環形鰭片相比，熱傳係數最高可增加達18.56%，而於高速區穿孔之鰭片熱傳係數則普遍略低於未穿孔環形鰭片，不同鰭片的流場特性亦將在本文之中探討。

This study uses experimental temperature data and inverse method along with three-dimensional computational fluid dynamics (CFD) software to investigate the heat transfer and fluid characteristics of perforated annular finned tube heat exchanger under mixed convection in a rectangular tunnel. This study examines the effects of parameters such as air inlet velocity, locations of perforation and fin spacing on the characteristics. Because of the complex air flow passing by the heat exchanger, the heat transfer coefficient on the fin is not uniform. Therefore the inverse method, using experimental temperature data combined with finite difference method and least-squares scheme is applied. This study also uses CFD software to calculate the heat coefficients, temperature and flow fields and compares them with experimental data and inverse results, in order to obtain the reliability among several flow models and different mesh systems. The results show that RNG k-ε is more suitable for this study, and increasing the air inlet velocity and fin spacing will enhance the heat ransfer. In Comparison with non-perforated fin, the one with perforation in the low-velocity wake region has higher heat transfer coefficients up to 18.56%, and heat transfer coefficients of fin with perforation in the high-velocity region are generally lower than non-perforated one. The fluid charateristics of different types of fins are also discussed.

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