本文以實驗溫度及逆算法搭配CFD軟體得出在四加熱管於空腔中，於自然對流時的熱傳及流場特性，及其管間距 d 與排列角度 θ 對上述特性之影響。流場經管式熱交換器時會產生複雜流動，為了有效了解不透明之空腔內流動模型，使用實驗量測溫度結合逆算法及CFD商用軟體進行熱傳現象之數值模擬，求得溫度場、流場及發熱量Q與實驗數據比較，探討不同紊流模型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紊流模型輔以增強型壁面處理較為符合實驗結果與趨勢；隨著間距增大會使空腔之最高溫下降，且管與管之間牽引作用降低，而不同管間距及排列角度會導致管式加熱器聚熱現象有明顯的差異此外，善用模擬軟體之後處理將溫度場與速度場可視化，能讓我們更便利、準確地分析空腔內之熱傳現象。

This study compares three-dimensional(3D) computational fluid dynamics (CFD) numerical simulation along with inverse method to experimental temperature data. In order to investigate the natural convection heat transfer and flow characteristics of four tubed heat exchangers in a closed cavity. The effect of two parameters including tube spacing and rotation angle of arrangement is examined. The 3D CFD inverse method are applied to predict the heat transfer characteristics. Temperature obtained by CFD at all points are in good agreement with the experimental results, then the temperature contour, streamline and heat transfer characteristics are determined. For the purpose of obtaining more accurate and reliable numerical results, the selection of flow models and mesh system must match temperature data. It is found that enhanced RNG k-ε turbulence model will be an appropriate flow model for all set of experiment. Comparison between 2D and 3D contours shows that under a 3D application, previous 2D studies may not be suitable. With the increase of tube spacing, heat dissipation will slow down the air velocity. When considering the rotation angle of arrangement, the traction effect induces the heat flow direction. To optimize the performance based on various uses, both parameters should be considered together.

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