使用伺服器之企業、機關與實驗室與日漸增，散熱問題的處理在伺服器系統的設計範圍裡佔有舉足輕重的地位。機架式架構之伺服器屬於扁平而狹長的空間，在眾多電子元件稠密的分佈在受限的空間中，欲克服高系統阻抗(System impedance)而能順利將熱源帶出，高風量、高靜壓的多級軸流式風扇(Mutil-stage Axial Fan)是必須的。本研究以此使用於伺服器系統散熱上之多級軸流扇為標的風扇，並使用計算流體動力學(Computational Fluid Dynamics, CFD)之商用軟體STAR-CD，利用傳統模擬方法與自行研發的一套新式模擬方法來模擬此一風扇之性能曲線。藉由兩種模擬方法所計算出的風扇流場，探討風扇內部葉片間及出入口流場在軸向與徑向平面的特性。新式模擬方法的計算結果與AMCA 210標準程序實驗結果相較，模擬得到之靜壓與流量誤差皆在3%以內，而傳統模擬方法之最大誤差則高達53%。使用新式模擬方法於此複雜幾何之多級軸流扇上，可以準確預測其性能曲線，證明此方法之可行性。

This study uses the STAR-CD, a commercial code of Computational Fluid Dynamics, to calculate and analyze the flow field characteristics and performance curve of a mutil-stage axial fan which has complicated geometry. A new computational approach as distinct from the conventional simulation method, which is widely adopted by investigators, is developed. The new simulation method uses the “added impedance” method to improve the prediction of the pressure, flow rate, and velocity distribution. The deviation of the calculated fan performance curve by using the new simulation method from the experimental results can attain a level less than 3%, which is a drastic improvement over that obtained by using the conventional method. The highest inaccuracy of the conventional method is even exceed 53%. It proved the new simulation method can be reliably applied to the mutil-stage axial fan which has complicated geomerty.

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