本研究針對共軛熱傳(Conjugate Heat Transfer, CHT)於鰭片散熱系統中的角色進行系統性探討，並分析其在自然對流與強制對流條件下對熱場與流場行為的影響。考量現行工程模擬中常省略固體與流體間熱交互之真實耦合機制，可能導致熱傳分析精度不足，本文採用RANS(Reynolds-Averaged Navier–Stokes)紊流模型結合CHT模擬方法，建立兩組具代表性之三維幾何模型：一為自然對流條件下的環狀鰭片結構，另一則為輻射狀鰭片與風扇耦合之強制對流散熱模組。模擬中考慮不同熱導性之材料，並分別比較有無CHT設定下之熱場分布、流場特徵與熱傳指標，如表面熱通量、Nusselt數、最大速度等。結果顯示，CHT對於鰭片末端溫度分布、局部浮力生成與對流強度具有顯著影響，特別是在自然對流下，忽略CHT會低估鰭片有效熱傳區域。於強制對流條件中，不同材料導熱性對整體熱傳效能之貢獻則相對受限於對流側瓶頸。本研究驗證了RANS模型於CHT問題中之可行性，亦指出其應用於各材料之散熱模組設計時所可能產生的偏差與限制，提供後續熱流模擬與熱管理設計之參考依據。

This study systematically investigates the thermal performance of radial fin structures under natural and forced convection conditions through refined numerical simulations. A conjugate heat transfer (CHT) modeling approach is adopted to accurately capture the bidirectional heat exchange between the solid fins and the surrounding fluid domain. Unlike conventional methods that simplify the fluid-solid interface using fixed heat transfer coefficients, the CHT method solves the energy equations in both domains simultaneously, ensuring physical continuity in both temperature and heat flux across the interface.
To evaluate the influence of material properties and airflow conditions, the study compares the performance of copper, aluminum, and polymer composite fins. CHT modeling results were validated against theoretical benchmarks (RMSE < 3%) and experimental data, leading to the selection of the SST k-ω turbulence model for its superior accuracy in near-wall flow and shear-dominated regions. The results demonstrate that incorporating the CHT approach significantly improves temperature gradient predictions (e.g., reducing heat flux error by 47.9% for AISI-304 fins) and reveals material-dependent limitations—polymer composites exhibited 52.6% lower v_max in natural convection when CHT was neglected.
These findings underscore the critical role of CHT modeling in thermal design, particularly for natural convection scenarios, and offer practical insights for optimizing fin-type cooling modules in electronic and energy systems.

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