本文採用逆向計算流體力學方法，結合實驗量測數據與最小平方法，預測密閉空腔內兩個矩形熱箱之自然對流熱傳特性，其中一熱箱上方配置相變化材料，另一個熱箱則未配置相變化材料。研究中比較層流模型、零方程式模型、標準k-ε模型與RNG k-ε模型所得之均方根誤差、最大速度及流場分布，以選定不同時間階段較適用之流動模型，並根據模擬結果修正自然對流經驗公式。最後，分析石蠟於不同時間下之吸熱率，以及相變化材料對溫度分布之影響。
結果顯示，本研究由加熱初期至穩態階段分別適用不同流動模型：60s時以層流模型之預測結果較佳；120s到8000s期間以零方程式模型較為適用；自10000s起則以RNG k-ε模型之整體預測結果較佳。由模擬結果可知，石蠟吸熱率於6000s時達1.31W；兩熱箱之最大溫差則出現在8000s，實驗與模擬結果分別為3.32K與4.26K。整體而言，相變化材料可有效延緩熱箱升溫，顯示其有助於提升系統之暫態熱管理效能。

This study employs an inverse CFD method combined with experimental measurements and least-squares analysis to predict the heat transfer characteristics of a two-heater system consisting of a PCM-equipped hot box and a reference hot box.Different flow models are evaluated by comparing the RMSE and flow field distributions, and the most suitable model is selected for each stage of the transient process. The heat absorption rate of the paraffin wax and the temperature difference between the two hot boxes are also investigated.
The results show that different flow models are more suitable for different stages of the heating process. The laminar model provides the best predictions during the initial stage, the zero-equation model performs best during the intermediate stage, and the RNG k-ε model was selected for the later stage based on the combined evaluation of RMSE, maximum velocity, and flow-field characteristics. The maximum heat absorption rate of the paraffin wax is 1.31W at 6000s. In addition, the maximum temperature difference between the two hot boxes occurs at 8000 s, reaching 3.32 K and 4.26 K in the experiment and simulation, respectively. Overall, the incorporation of PCM effectively delays the temperature rise of the PCM-equipped hot box and improves transient thermal management performance.

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