近年來土地開發、科技進步帶來的副作用對環境造成嚴重負擔，使許多區域的空氣品質不佳，由世界衛生組織(WHO)發表的空氣汙染報告中，指出細懸浮微粒(PM2.5)濃度超標且空氣污染的情形日益嚴重，使民眾開始關注空氣清淨機、口罩等過濾空氣的商品。現代人因工作及生活型態，需長時間待在室內環境，為了改善室內空氣品質，本文參考市售車用空氣清淨機設計多種參數來進行改良，並就其設計及參數變化對氣動性能之影響進行討論；先依據CFD模擬結果針對流量缺失處提出改良方案，而後將影響風扇整體性能甚巨參數做最佳化的設計；其考量之風扇參數主要有導葉數、葉片形狀、葉片數量、舌部間隙、出口斜角、葉輪高度及葉輪內外徑。
　　首先利用擺放適當的導葉數來提升風機性能，但其效果有限，而後藉由流場可視化將風扇整體流場損失進行有系統性的參數規劃來做進一步地探討與改善，經以上參數分析討論後，得到一組良好的風扇參數以應用於空氣清淨機內。最後為驗證此最佳化風扇設計之數值模擬的準確性，將其模型利用加工技術實體化，並進行相關性能實驗與噪音量測，所獲得之測試結果與數值模擬相互比對後，顯示模擬值與實驗值的性能十分相近，因此可得知數值模擬有其一定的準確度。此外在相同尺寸轉速的條件下，所設計出的風扇流量優於原始11.2%且噪音值降低2dBA，並且在轉速2,500rpm時其流量預估可達90CARD；另外透過將葉輪直徑與高度增加為原先的8%及37%後，可使此尺寸較大的風扇噪音值不變且流量提升56%，由此可知所設計的風扇已達下一代產品所期望的120CARD流量。因此綜合上述之研究成果顯示，本文所設計的應用於車內空氣清淨機之前傾式離心扇，其風扇設計流程以及參數討論可提供後續相關研究為重要的設計參考之一。

　　In recent years, the land development and technological progress make significant impact on environment and let air quality become poor. However, WHO's air pollution report pointed out that the particulate matter concentration surpassed the standard several times and air pollution spread throughout the world were leading people to pay attention on air cleaners, masks and other air filter products. Unfortunately, owing to work and life type, many people need stay in an indoor environment all the times. In order to improve the indoor air quality, this study refers to the commercial air cleaner designed for vehicles to propose several improved designs with the aids of a comprehensive parametric study on the geometry of air cleaner. The corresponding impacts of aerodynamic performance caused by key parameters are checked using the numerical technology. The design parameters considered here include outlet angle and number of the guiding vane, shape and number of the blade, geometry and clearance of the cutoff, inner/outer diameter and height of the impeller.
First of all, flow field at the discharge is analyzed and modified by an appropriate arrangement on the guiding vane to attain a performance enhancement with the smaller flow impact. Later, with the aids of CFD tool, the detailed flow visualization and systematic parametric study are executed to identify the performance influence induced by each design parameter. Thereafter, an optimizing rotor incorporated with a proper casing is designed with an adequate parameter setting, which is obtained after the aforementioned procedure. Finally, in order to verify the credibility of CFD simulation, the prototype of optimized design is manufactured by CNC machine to carry out the corresponding experimental performance verifications. In addition, to ensure a reliable outcome, the fan’s performance and noise tests are executed in AMCA and semi-anechoic chambers by following AMCA-210-07 and CNS-8753 codes, respectively.
By comparing the experimental and numerical results, a remarkable agreement between these performance curves is observed to validate the reliability of numerical simulation. Besides, under the same size and rotating speed, the aerodynamic performance of optimized design is superior to the reference fan by 11.2% rise on flow rate with a 2-dBA noise reduction, which is capable to meet with the demand of 90 CADR (clean air delivery rate) when operating at 2,500 rpm. Moreover, with 8% and 37% increase on rotor’s diameter and height, an enlarged fan is proposed based on this optimized design to generate a similar noise level and a 56% increase on its maximum flow rate, which can meet with the 120-CADR demand of the next-generation air cleaner. In summary, this study successfully establishes a reliable and systematic scheme to design the small air cleaner or the related products. Besides, the corresponding performance influences caused by important design parameters are analyzed and summed up for servings as the design guide for the forward-curved centrifugal fan applied on the air cleaner used in vehicle.

[1] 台灣癌症基金會，＂台灣人小看肺癌的5大事實」首度揭密！＂，http://www.canceraway.org.tw/。
[2] 行政院環保署，＂辦公大樓上班族之健康危害～病態建築物症候群＂，http://www.epa.gov.tw/。
[3] ANSI/AMCA Standard 210-07 (ANSI/ASHRAE 51-2007), “Laboratory Method of Testing Fans for Aerodynamic Performance Rating,” Air Movement and Control Association, Inc., 2007.
[4] CNS 8753, “Determination of Sound Power Level of Noises for Fan, Blower, and Compressors,” Chinese National Standard, 1982.
[5] ISO 3745, “Acoustics – Determination of Sound Power Levels of Noise Sources Using Sound Pressure – Precision Methods for Anechoic and Hemi-Anechoic Rooms”, 2003.
[6] 蘇聖拭、陳世雄，“軸流泵葉輪與導葉之設計分析，”中國機械工程學會第十三屆學術研討會論文集，298-306頁，1996 年。
[7] Howard, J.H.G. and Lennemann, E. “Measured and Predicted Secondary Flows in a Centrifugal Impeller,” ASME, Journal of Engineering for Power, Vol. 93,, pp. 126 – 132, Jan. 1971.
[8] McDonald, G.B., Lennemann, E., and Howard, J.H.G., “Measured and Predicted Flow near the Exit of a Radial-Flow Impeller,” ASME, Journal of Engineering for Power, Vol. 93, pp. 441 – 446, Oct. 1971.

[9] Abramian, M., and Howard, J.H.G., “Experimental Investigation of the Steady and Unsteady Relative Flow in a Model Centrifugal Impeller Passage,” ASME, Journal of Turbomachinery, Vol. 116, pp. 269 – 279, Apr. 1994.
[10] Howard, J.H.G., and Kittmer, C.W., “Measured Passage Velocities in a Radial Impeller with Shrouded and Unshrouded Configurations,” ASME, Journal of Engineering for Power, Vol. 97, pp. 207 – 213, Apr. 1975.
[11] Raj, D. and Swim, W. B., “Measurements of the Mean Flow Velocity and Velocity Fluctuations at the Exit of an F-C Centrifugal Fan Rotor,” Journal of Engineering for Power, Vol. 103, pp. 393-399, 1981.
[12] Wright T., “Centrifugal Fan Performance With Inlet Clearance＂, ASME Journal of Engineering for Gas Turbines and Power, Vol.106, pp. 906-912, 1984.
[13] Elholm, T., Ayder, E., and Van den Braembussche, R., “Experimental Study of the Swirling Flow in the Volute of a Centrifugal Pump,” ASME, Journal of Turbomachinery, Vol. 114, pp. 366 – 372, Apr. 1992.
[14] Lin, S. C., “A Novel F-C Centrifugal Fan Design for Improved Performance,” Department of Mechanical Engineering, Technical Report, Tennessee Technological University, 1982.

[15] 吳慶財，“前傾式離心扇之實驗設計”，國立台灣工業技術學院機械工程技術研究所碩士論文，1993年。
[16] Rice, M.S, Handbook of Airfoil Sections for Light Aircraft, 1997.
[17] www.airfoils.com,Airfoils , Incorporated, 2000
[18] 黃家烈，“筆記型電腦冷卻風扇之研究”， 國立台灣科技大學機械工程技術研究所博士論文，2001 年。
[19] 孫鈞瑋，“前傾式離心風機數值與實驗之整合研究” 碩士論文，國 立台灣科技大學機械工程研究所，2003。
[20] Arnone, A.,“ Viscous Analysis of Three-Dimensional Rotor Flows Using a Multigrid Method”, NASA TM-106266, 1993.
[21] Su, M. M., Gu, C. A., and Miao, Y. M., “Numerical Study of Viscous Flow Field in Mixed-Flow Fan,” Journal of Xi’an Jiaotong University, Vol. 30, No. 10, pp. 55-63, 1996.
[22] Patankar, S. V. and Spalding, D. B., “A Calculation Procedure for Heat Mass and Momentum Transfer in Three-Dimensional Parabolic Flows,” International Journal of Heat Mass Transfer, Vol. 15, pp. 1787-1806, 1972.
[23] 林顯群、黃家烈、簡宏斌，“軸流風扇之數值模擬與實驗分析”，中華民國「航太學會/燃燒學會/民航學會」航太聯合會議，桃園，107-117頁，中華民國八十八年。

[24] 林顯群、黃家烈、許豐麟，“進風口面積在新式筆記型電腦冷卻扇之研究”，中華民國機械工程學會第十七屆全國學術研討會論文集，高雄，中華民國八十九年。
[25] 游裕傑，“離心式電腦風扇的設計與分析”，國立成功大學機械工程學系碩士論文集，2002 年。
[26] 周志成，“新型離心式風扇數值與實驗整合研究”，國立台灣科技大學機械工程技術研究所碩士論文，134-149頁，中華民國95年。
[27] Lin, S. C. and Tsai, M. L. An Integrated Performance Analysis for a Backward-Inclined Centrifugal Fan. Computers & Fluids, Vol. 56, p. 24-38, 2012.
[28] 洪敏翔、黃正弘，離心式風扇最佳幾何形狀之設計，碩士論文，國立成功學系統與船舶機電工程學系研究所，2011。
[29] 尤清，“無扇葉風扇之數值與實驗整合研究”，國立台灣科技大學機械工程技術研究所碩士論文，126-165頁，中華民國103年。
[30] 高驅科技官網 www.GaoDrive.com
[31] 武漢新瑞科電氣技術有限公司 http://newrock_wh.dzsc.com/
[32] 張瑞釗、許忠福、施良磷、張起領，“渦輪葉片參數設計法，”中山科學研究院，第一研究所研究報告，1986 年。
[33] 蘇聖斌、陳世雄，“軸流泵葉輪與導葉之設計分析”，中國機械工程學會第十三屆學術研討會論文集，pp. 298-306，1996 年。
[34] Bleier, Frank P., “Fan Handbook: Selection, Application, and Design”, McGraw Hill, 1997.
[35] Morinushi, K., “The Influence of Geometric Parameters on F. C. Centrifugal Fan Noise,” Journal of Vibration, Acoustics, Stress and Reliability in Design, Vol. 109, pp. 227-234, 1987.
[36] Eck, I. B., “Fans: Design and Operation of Centrifugal, Axial-Flow
and Cross-Flow Fans”, Pergamon Press, New York, 1973.
[37] Neise, W., “Noise Reduction in Centrifugal Fans: a Literature Survey,” Journal of Sound and Viberation, Vol. 45, No. 3, pp. 375-403, 1976.
[38] Kondo, L. and Aoki, Y., “Noise Reduction in Turbo Fans for Air Conditioners,” Technical Review-Mitsubishi Heavy Industries, Vol. 26, No. 3, pp. 173-179, 1989.
[39] 邱至聖，翼型後傾式離心風機之設計參數分析與風輪製作省力化之研發，國立台北科技大學自動化科技研究所碩士學位論文，2013。
[40] Patankar, S. V. and Spalding, D. B., “A Calculation Procedure for Heat Mass and Momentum Transfer in Three-Dimensional Parabolic Flows,” International Journal of Heat Mass Transfer, Vol. 15, pp. 1787-1806, 1972.
[41] Launder, B. E. and Spalding, D. B., “Lectures in Mathematical Models of Turbulence,” Academic Press, London, England, 1972.
[42] Van, Dooremaal and Raithby, G. D., “Enhancement of the SIMPLE Method for Predicting Incompressible Fluid Flows”, 1983.
[43] 鄭育政，具襟翼之翼形應用於風扇設計的可能性研究碩士論文，國立台灣科技大學機械工程研究所，2012。
[44] 林顯群、徐志佾，“風機濾網機組之流場模擬分析”，潔淨科技季刊，38期，2017年，6月。