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系統識別號 U0026-0812200911374303
論文名稱(中文) 表面粗糙效應對軸流式冷卻風扇性能之影響
論文名稱(英文) The Study of Surface Roughness Effects on Axial Cooling Fan Performance
校院名稱 成功大學
系所名稱(中) 航空太空工程學系專班
系所名稱(英) Department of Aeronautics & Astronautics (on the job class)
學年度 93
學期 2
出版年 94
研究生(中文) 劉志弘
研究生(英文) Chih-Hong Liu
電子信箱 lau8210kimo@yahoo.com.tw
學號 P4792103
學位類別 碩士
語文別 中文
論文頁數 88頁
口試委員 指導教授-蕭飛賓
口試委員-江志煌
口試委員-潘永堅
中文關鍵字 邊界層控制  風扇性能  散熱風扇 
英文關鍵字 cooling fan  fan performance  boundary layer control 
學科別分類
中文摘要   目前邊界層控制(Boundary layer control)不只在研究領域上有充足的參考資料,在實際上也已經有許多應用。例如渦流產生器(vortex generator)可改善飛機飛行性能、運動衣的粗造表面或微小突起物可減少運動選手空氣阻力等。本論文主要是探討具有粗糙度之扇葉表面的軸流散熱風扇特性,藉由氣流通過粗糙度表面後所產生的動能以延遲氣流分離,進而達到性能改善之目的。研究以實驗方法為主,以獲得粗糙度型式、尺寸與配置方法與風扇性能之相對關係。

  研究中所探討的風扇性能包含了靜壓、流量、需求功率、風扇效率以及聲壓。實驗證明具有適當比例以及尺寸的粗糙度扇葉面能夠有效提昇風扇靜壓-流量關係以及風扇效率,最多達到11%以上,並能抑制風切頻率所對應之聲壓。就風扇靜壓-流量關係以及風扇效率而言,圓凸狀的效用高於圓凹狀,且單排圓凸狀粗糙度最佳,但其位置必須位於50%葉片弦長之前。圓凹狀粗糙度則在抑制風切頻率聲壓上的效用較高。以4000 rpm運轉之風扇使用粗糙度所獲得的改善較為明顯;轉速較低時,效用並不明顯。
英文摘要   There have been many studies and actual applications of boundary layer control methods in fluid and aerodynamic related problems. For example, the vortex generator can improve aircraft performance and the rough surface or small dots can reduce the drag force of athletes. This experimental study is intended to investigate the influences regarding the shape, size, and locations of the fan’s surface roughness on the fan performance of cooling fan for a Personal Computers (PC). The surface roughness of the fan is expected to increase the mixing of momentum near the boundary layer so as to delay or even suppress the occurrence of boundary layer separation; hence, the performance of a cooling fan can be improved.

  In this study, the parameters to be investigated of fan performance include the static pressure (P) rise, flow rate (Q), required power, and noise. Experimental results indicate that the surface roughness with suitable shape and location is effective to increase the fan’s P-Q curve and fan efficiency, specifically the maximum improvement is as much as 11%; and the sound pressure level at the blade passage frequency can be reduced effectively. With respect to the roughness shape on the fan studied, the convex dot shape of the roughness is more effective than that of the concave one regarding the P-Q curves and the fan efficiency. In the addition, the arrangement of one row of convex dots performs better that of the concave one, which is even better to reduce the noise intensity at the blade passage frequency. However, the location of the row of dots must be located before 50%-chord location. Results also confirm that the introduction of surface roughness has very significant effect on fan performance improvement at the speed of 4000 rpm, but with less performance at lower speeds in the present study.
論文目次 中文摘要........................................................i
英文摘要........................................................iii
致謝................................................................v
目錄................................................................vi
表目錄............................................................ix
圖目錄............................................................x
符號說明........................................................xv

第一章 前言....................................................1
1.1 風扇簡介...................................................3
1.1-1 風扇種類................................................3
1.1-2 風扇性能................................................3
1.1-3 風扇設計原理........................................7
1.1-4 系統阻抗................................................8
1.2 邊界層理論與控制方法...........................9
1.2-1 空氣特性................................................9
1.2-2 邊界層概論...........................................10
1.2-3 邊界層與阻力之關係...........................11
1.2-4 邊界層控制方法...................................12
1.2-5 其它增進性能之方法...........................14
1.3 研究動機與目的......................................15
1.5-1 研究動機...............................................15
1.5-2 目的.......................................................16

第二章 實驗規劃與步驟...............................17
2.1 實驗設備..................................................17
2.1-1 風洞.......................................................17
2.1-2 聲音量測設備.......................................18
2.1-3 半無響室...............................................18
2.2 模型設計與規劃......................................20
2.2-1 單列式Roughness扇葉..........................21
2.2-2 多列式Roughness扇葉..........................22
2.3 實驗步驟...................................................22

第三章 結果與討論........................................24
3.1 凸狀粗糙型式之扇葉...............................24
3.1-1 A-Roughness性能表現...........................24
3.1-2 UA-Roughness性能表現........................25
3.1-3 SA-Roughness性能表現.........................26
3.2 凹狀粗糙型式之扇葉...............................27
3.2-1 B-Roughness性能表現...........................27
3.2-2 UB-Roughness性能表現........................27
3.2-3 SB-Roughness性能表現.........................28
3.3 Roughness形狀對風扇性能之影響..........28
3.4 粗糙度尺寸對風扇性能之影響...............30
3.5 Roughness設置點對風扇性能之影響......31
3.6 單列式與多列式Roughness的綜合比......32

第四章 結論與建議........................................34
4.1 結論...........................................................34
4.2 建議...........................................................36

參考文獻.........................................................37
自述
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