- 學位論文
逆向工程用於冷凍食品展示櫃室外機風扇性能提升之研究
Performance Enhancement of Outdoor Unit Fan in Refrigerating Showcases Using Reverse Engineering
摘要
商業冷凍往往耗電量很大，且在冷藏展示櫃作動時其冷凝器有惱人的噪音，故開發省電且低噪音之風扇是趨勢。又傳統是以正向工程(Foeward Engineering)進行產品開發，既費時又花費高。因此本研究即針對冷凝器之風扇，發展出結合電腦輔助流場分析與實驗測試之整合技術，配合逆向工程，協助業者提升產品開發之速度，並生產出省電及低噪音之冷凝器風扇。研究所採用方法首先是依業者所提供之原型葉片，進行逆向工程後取得原型葉片之電腦CAD圖檔，接著選取合適之翼形斷面，取代原始葉片在不同半徑之薄片形斷面。待取得翼型扇葉的CAD檔案後，利用FLUENT模擬分析原型與翼形風扇之內部流場特性及性能曲線，接著將CAD圖檔由CNC車床車削後得到之翼形葉片進行性能實驗量測。經模擬值與實驗測量結果比對，確認所建立之模擬模式準確且可被接受，進ㄧ步的修改翼形葉片。在找出最佳翼形之斷面形狀後，則使用快速成型進行量產，使用於展示櫃之冷凝器上。 使用逆向工程技術取代原本需加工原型進行實驗的方式，降低重覆實驗所造成的高成本問題。模擬之研究結果發現葉片由原型葉片改為682翼形後風扇整體性能提升約4%；實驗方面，622翼形葉片與原型葉片比較，噪音降低1.3dB(A)左右。
並列摘要
Because both power consumption and noise of refrigerating-showcase condenser are large, the development of fan with energy saving and low noise is the future trend. In addition, the traditional forward engineering for product development is a time-consuming and cost-spending method. Therefore, the purpose of this study is to develop an integrating reverse engineering technique for an airfoil condenser fan, which combines the computational fluid dynamics (CFD) analysis and experimental measurement, and to help the industry to enhance the speed of product manufacture and production of energy saving and low noise fan. The research method adopted in this study is as follows. First, a reverse engineering is utilized to create a CAD drawing file of origin flat-type fan hardware. Second, an adaptive airfoil cross section replacing the flat-type one at different radii is used to build a new airfoil fan CAD file without changing the original fan size. Third, the CFD software FLUENT is employed to simulate the airflow passing through both airfoil-type and flat-type fan systems. The predicting performance curves of fans obtained from the CFD simulation results are analyzed and compared. Four, then an airfoil-section fan is manufactured according to the resultant airfoil-section profile and then is experimentally investigated. In comparing the simulation results with the experimental data, changing the aerofoil shape step-by-step until the differences between predicted and experimental results are accepted. Finally, a CNC mill following the eventual CAD drawing file is applied to build a stainless steel mold for mass produce. It was found that to create a high performance airfoil fan with same size as the original non-airfoil one by integrating reversed engineering technology is feasible. The results show that the sound pressure level (SPL) on type 622 blade-cutting based fan is lower than the original one about 1.2 dB (A), in practical, and the values of characteristic curve(P-Q curve) for type 682 blade-cutting based fan is larger than the original one about 5%.