在室內空調系統中，架設於通風管道中的管道風扇其主要功能為，將空調機所送出之新鮮空氣順利吹送至各個管道末端的場所。為了使空氣在管道中能克服更大的阻抗，本研究設計管道風扇出口導流葉片，試圖將流出葉輪之流體由迴旋流動導為直接流出風機，以達到提升風機性能的目的。首先選用一方形風機外殼之管道風扇，以數值模擬軟體STAR-CD分析其最大效率點之流場，並建立一馬達罩來消除馬達周圍之巨大渦流及逆流現象，除了滿足流體能切入導流葉片前緣之基本設計需求，並大幅提升風機性能使最大效率點靜壓增加8.6%。接著根據加裝馬達罩之風機流場，分別設計出8片及12片導流葉片，但風機性能並未因此導流葉片而有所提升，乃因導流葉片助長流場中之渦流發展，其負面影響大於對其他流體導流所造成的正面影響。最後藉由修改特定導流葉片的寬度，來減緩風機內側渦流的發展，使最大效率點的靜壓較僅加裝馬達罩之風機增加2%，而較原型風機則增加10.8%，最大靜壓卻較原型風機降低3.4%，表示針對最大流量點所設計之導流葉片，不一定能在其他工作範圍有較佳之表現，且由氣流噪音源之數值結果可知，若要改善流場消除低速渦流，有可能會因較強的紊流擾動而增大噪音。

The major function of the in-line fan inside a duct is to offer the sufficient static pressure for transporting the fresh air from air conditioner to duct outlet. This research intends to design the guide vanes at the fan discharge to remove the air spin and convert some of the energy losses into additional static pressure; thus, the in-line fan can overcome the system resistance more smoothly inside ducts. First of all, an in-line fan with a square housing is chosen to execute and analyze the numerical flowfield simulation at its maximum-efficiency point. Then, an extra motor housing is proposed to eliminate the vortex and reversed flow around the motor based on the flow patterns observed from the CFD results. This modification not only enhances the static pressure by 8.6% at its peak efficiency, but also creates a stable incoming flow at the leading edge of the guide vane. Thereafter, two guide-vane configurations, 8-blade and 12-blade, are constructed according to the flow patterns around the motor housing. Nevertheless, the numerical result shows that fan performance is not improved owing to the stronger vortex development caused by the guide vanes at the housing corner. Hence, width modification on the guide vanes is applied to diminish the vortex strength and thus generate an extra 2% pressure increase at the peak efficiency point. In summary, the best guide-vane design considered in this study results in a 3.5% increase on the maximum flow rate and a 10.8% pressure enhancement at its operation point compared to those of the original in-line fan.

[1] 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/ ，2003年。
[2] Smarthome Pro, http://www.smarthomepro.com/3011.html .
[3] ThomasNet, http://news.thomasnet.com/fullstory/483922 .
[4] Wave Plumbing, http://www.waveplumbing.com/store/ .
[5] Allproducts, http://www.allproducts.com/machine/jouning .
[6] Wu, C. H., “A General Theory of Three-Dimensional Flow in Subsonic and Supersonic Turbomachines of Axial, Radial, and Mixed-Flow Types”, Trans. ASME, Vol. 74, pp. 1363-1380, 1952.
[7] 孟德化，“軸流式風扇葉片設計”，成功大學航太所論文，1995年。
[8] Chen, H. and Williams, M. H., “Panel Method for Counter Rotating Propfans,” Journal of Propulsion and Power, Vol. 7, No. 4, July-Aug., 1991.
[9] 江易儒，“導管風扇之流場分析”，成功大學航太所碩士論文﹐1996年6月。
[10] 張裕慶，“軸流風扇之數值模擬”，國立台灣工業技術學院機械工程技術研究所碩士論文，1997年7月。
[11] McFarland, E. R., “Solution of Plane Cascade Flow Using Improved Surface Singularity Methods”, Journal of Engineering for Power, Vol. 104, pp. 668-674, 1982.
[12] 林顯群、黃家烈、簡宏斌、沈銘秋，“軸流風扇之數值模擬與實驗分析”，1999中華民國「航太學會/燃燒學會/民航學會」航太聯合會議，桃園，pp. 107-117，中華民國八十八年。
[13] 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，pp. 621-628，中華民國八十九年。
[14] 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。
[15] Zhang, H. Y., Pinjala, D., Navas, O. K., Iyer, M. K., Chan, P. K., Liu, X. P., Hayashi, H., and Han, J. B., “Development of Thermal Solutions for High Performance Laptop Computers”, 2002 IEEE Inter. Society Conference on Thermal Phenomena, pp. 433-440, 2002.
[16] 孫鈞瑋，“前傾式離心風機數值與實驗之整合研究”，國立台灣科技大學機械工程技術研究所碩士論文，2004年。
[17] 李延青、鄭名山、李隆正，“後傾離心風機數值模式建立”，第二十二屆中國機械工程學會論文集，中壢，2005年。
[18] 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研究所碩士論文，2006年。
[19] 林顯群、陳來富、周雅文、蔡明倫、周志成，“In-Line Fan流場模擬分析”，中國機械工程學會第二十三屆全國學術研討會論文集，永康，2006年。
[20] Kim, T. H., Takao, M., Setoguchi, T., Kaneko, K., and Inoue, M., “Performance Comparison of Turbines for Wave Power Conversion”, International Journal of Thermal Science, Vol. 40, pp. 681-689, 2001.
[21] Suzuki, M. and Arakawa, C., “Guide Vane Effect of Wells Turbine for Wave Power Generator”, International Journal of Offshore Polar Eng, Vol. 10, pp. 153-159, 2000.
[22] Takao, M., Satoguchi, T., Kim, T.H., Kaneko, K., and Inoue, M., “Performance of the Wells Turbine with 3-D Guide Vanes”, Proc. of the 10th International Offshore and Polar Engineering Conference, pp. 381-386, 2000.
[23] Govardhan, M. and Dhanasekaran, T. S., “Effect of Guide Vanes on the Performance of a Self-Rectifying Air Turbine with Constant and Variable Chord Rotors”, Renewable Energy, Vol. 26, Issue 2, pp. 201-219, June 2002.
[24] Christopher, E. Hughes, “Aerodynamic Performance of Scale-Model Turbofan Outlet Guide Vans Designed for Low Noise”, AIAA-2002-0374.
[25] 林顯群、林益輝、賴豐泉，“吹風機性能及噪音之改善研究”，2002年。
[26] 吳兌倩，“流線型鰭片散熱座數值與實驗之整合研究”，國立台灣科技大學機械工程研究所碩士論文，2004年。
[27] Hüebner, G., “Noise Generated by Centrifugal Fans”, Siemens- Zeitschrift, Vol. 8, pp. 145-155, 1959.
[28] Schlichting, H., “Application of the Boundary Layer Theory to Flow
Problems of Turbo Machines”, Siemens-Zeitschrift, Vol. 33, No. 7, pp. 74-82, 1959.
[29] Neise, W., “Noise Reduction in Centrifugal Fans：A Literature Survey”, Journal of Sound and Vibration, Vol. 45, No. 3, pp. 375-403, 1976.
[30] Neise, W., “Review of Noise Reduction Methods for Centrifugal Fans”, Journal of Engineering for Industry, Vol. 104, pp. 151-161, 1982.
[31] 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.
[32] 洪宗揚，“前傾式離心風機之減噪研究”，國立台灣工業技術學院機械工程技術研究所碩士論文，1996年。
[33] 呂水煙，“前傾式離心風機之減噪研究”，國立台灣工業技術學院機械工程技術研究所碩士論文，1997年。
[34] 歐陽百峻，“新式筆記型電腦冷卻風扇之實驗研究”，國立台灣科技大學機械工程技術研究所碩士論文，2000年6月。
[35] STAR-CD, Version 3.15, Methodology, 2001.
[36] ANSI/AMCA Standard 210-99 (ANSI/ASHRAE 51-1999), “Laboratory Method of Testing Fans for Aerodynamic Performance Rating”, Air Movement and Control Association, Inc., 1999.
[37] 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 and Mass Transfer, Vol. 15, pp. 1787-1806, 1972.
[38] Lilley, G. M., “On the Noise from Jet,” Noise Mechanisms, AGARD-CP-131, pp. 13.1-13.12, 1974.
[39] Goldstein, M. E., “Aeroacoustics”. McGraw-Hill, New York, 1976.
[40] Yakhot, V., Orszag, S. A., Thangam, S., Gatski, T. B., and Speziale, C. G., “Development of Turbulence Models for Shear Flows by a Double Expansion Technique”, Phys. Fluids, Vol. A4, No. 7, pp. 1510-1520, 1992.
[41] Kraichnan, R., “Diffusion by a Random Velocity Field”, Phys. Fluids, Vol. 13, No. 1, pp. 22-31, 1973.
[42] Karweit, M., Blanc-Benon, Ph., Juve, D., and Comte-Bellot, G., “Simulation of the Propagation of an Acoustic Wave through a Turbulent Velocity Field: A Study of Phase Variance”, Journal of the Acoustical Society of America, Vol. 89, No. 1, pp. 52-62, 1991.