本研究針對高功率伺服器在強制對流環境下之散熱需求，提出系統性的鰭片構型優化策略。有別於傳統不可壓縮流假設，本數值模擬採用全域可壓縮流求解器以保留流體受熱加速之真實物理效應，並導入 BCM（Building–Cube Method）之笛卡爾網格系統，結合沉浸式邊界法（Immersed Boundary Method, IBM）精確解析複雜固體邊界。為全面評估不同工況，研究設定入口流速為 1 m/s（靜音節能模式）、4 m/s（常規運行模式）與8 m/s（極限運轉模式），並系統性分析直線、波浪（Wave Fins）、交錯鰭片（Offset Strip Fins, OSF）及三角翼渦流產生器（Delta Winglet Pairs, VG）等多元結構之熱傳性能。
研究結果顯示，散熱效能的提升並非單純取決於表面積的增加，而是高度仰賴流場微觀機制與運行雷諾數的匹配。在 1 m/s 的低速工況下，流場受黏滯力主導，複雜構型易引發流動停滯與無效壓降，此時維持流道暢通的寬間距直線鰭片展現出最佳的能效比（η = 1.06）。當流速提升至 4 m/s 時，慣性力促使流動機制產生顯著變化：交錯鰭片透過持續促使熱邊界層重新發展，展現出高達 34.2的平均紐塞數與230 W 的總熱傳量，但其高達 63 Pa 的壓降使其能效比顯著下降至 0.76；相反地，三角翼渦流產生器在高速下成功誘發強烈的三維縱向渦流，在維持與基準模型相近之極低壓降（24 Pa）的前提下，將總熱傳量提升至 129 W，使其能效比達到 1.10。最後，在 8 m/s 的極端工況下，本研究證實了大振幅波浪鰭片因嚴重的流動分離導致流體動力學機制失效，壓降呈非線性大幅上升；反觀交錯鰭片仍維持優異之散熱能力，且壓降損失處於可接受範圍。總結而言，針對伺服器散熱設計，若以極限熱傳能力為首要目標，交錯鰭片為較佳選擇；若追求系統整體能效最佳化，則三角翼渦流產生器為具有工業應用價值之設計方案。

This study provides an in-depth investigation into the design and optimization of heat dissipation fins for high-power servers under forced convection. Unlike traditional incompressible flow assumptions, this study employs a fully compressible flow solver to preserve the physical effects of flow acceleration due to thermal expansion. The simulation utilizes the Building–Cube Method (BCM) with an orthogonal grid structure, combined with the Immersed Boundary Method (IBM) to accurately resolve complex solid boundaries. To comprehensively evaluate thermal-hydraulic performance, inlet velocities of 1 m/s (low-noise/energy-saving mode), 4 m/s (normal operational mode), and 8 m/s (extreme operational mode) were simulated across various fin geometries, including straight fins, wavy fins, offset strip fins (OSF), and delta winglet pairs (VG).
The results reveal that heat transfer enhancement depends not merely on increased surface area, but heavily on the coupling between micro-flow mechanisms and the operating Reynolds number. Under the low-speed condition of 1 m/s, viscous forces dominate, and complex geometries tend to cause flow stagnation and ineffective pressure drops. Consequently, straight fins with a wider pitch exhibit the best energy efficiency ratio (1.06) by maintaining unobstructed flow channels. Conversely, at 4 m/s, inertial forces trigger significant changes in the flow mechanism. The OSF achieves a high average Nusselt number of 34.2 and a total heat transfer rate exceeding 230 W by continuously restarting the thermal boundary layer; however, its substantial pressure drop of 63 Pa significantly reduces its energy efficiency ratio to 0.76. In contrast, the VG successfully induces strong three-dimensional longitudinal vortices at this higher flow speed, effectively mitigating thermal dead zones while maintaining a low pressure drop (24 Pa) comparable to the baseline model and raising the total heat transfer to 129 W. Consequently, the VG achieves the highest energy efficiency ratio of 1.10 among all configurations, representing the optimal balance between heat transfer enhancement and pumping-power penalty. Finally, under the extreme condition of 8 m/s, this study demonstrates that large-amplitude wavy fins suffer significant flow-induced performance degradation due to severe flow separation, leading to an non-linear increase in pressure drop and a substantially reduced energy efficiency ratio. In contrast, the OSF not only maintains its high heat dissipation capability but also exhibits an acceptable pressure drop penalty. This study concludes that for server cooling designs, OSF represents the most effective solution for extreme heat dissipation, whereas VG represents a promising design solution for maximizing system energy efficiency.

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