本文針對輕薄型電腦的散熱需求，設計了整體尺寸為38 mm×38 mm×10 mm之小型雙吸入式離心風扇，其特點在於混合了前傾式及後傾式葉片的葉輪設計，具有高風量及高揚程的優點。對於風扇模型的網格產生方式，在定義了風扇外形及葉片的幾何參數後，利用Fortran程式語言撰寫模型網格程式，直接產生所需的網格資料檔，讓CAE軟體讀取並分析。而經由數值軟體的流場可視化功能，探討整體風扇及細部區域的流場現象，做為設計改良之參考或比較。

文中採用有效且準確的有限體積法，將得到的數值解經由能量的觀點，建立風扇性能曲線，而以設計之基本個案為基礎，比較參數變化對性能曲線之影響。並對葉輪結構作應力及振動分析，提供設計時之安全係數及自然頻率，預防結構破壞。全文的設計分析步驟可提供研究者及設計者一個完整且有系統的風扇開發流程。

In this study, the cooling desire of a slim computer is considered. The innovated double-entry centrifugal fan（38 mm×38 mm×10 mm）focuses on the impeller combined forward and backward curved vanes. When the geometric parameters of casing and impeller are defined, this study use FORTRAN program language to generate model mesh data files which can be read by CAE sofeware. The main goal of this study is to investigate, via a CAE analysis, the globe and local flow response of the designed centrifugal fan during operation. And by the flow visualization utility, the discussion can be compared and referred in fan design processes.

The fan characteristic curves are generated by energy aspect using the numerical solutions. Thereafter, a parametric study on fan geometry is executed to enhance the cooling fan’s performance. Furthermore, a detailed discussion is given to identify those important parameters, which have great effect on fan performance. This study also analyses the structural and modal responses of the impeller to offer the safety factor and the natural frequencies. In order to fulfill above objectives, existing finite volume code: STAR-CD and finite element code: ANSYS are implemented to investigate the flow-field and structural behaviors of the designed centrifugal fan. Numerical analysis results show that the innovated fan proposed here demonstrates a superior performance over the traditional design.

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