葉片構型與背板粗糙度對橫流扇性能與噪音影響之研究

The Effect of Blade Type and Roughness of Rear Wall on the Performance and the Acoustic Noise of the Cross Flow Fan

陳益祥(Yi-Hsiang Chen)

指導教授 ： 施陽正

國立臺北科技大學/機電學院/冷凍空調工程系所/碩士(2005年)

摘要

為改善橫流扇的噪音特性，本研究利用計算流體力學軟體FLUENT 6.1針對(1)葉片排列型式 (2)葉片弦長 (3)葉片角度 (4)背板粗糙度等四個主要課題，經由所模擬出之聲壓位準分析其所產生之氣動噪音，並藉由觀測橫流扇內部流場的變化來探討對其性能之影響，電腦模擬時以出入口風門全開並固定風扇轉速，計算其出口風量與偏心渦元的特性。經由模擬結果顯示(1)不等節距葉片排列方式可以有效降低等節距葉片排列方式所產生的葉片頻率單音特性，對於抑制廣頻噪音亦有所幫助。(2)在葉片弦長10.3~12.09mm範圍內，增加葉片弦長會導致風扇整體性能降低，對於降低葉片噪音亦沒有顯著幫助。(3)在葉片角度80o~100o範圍內，降低葉片角度會導致其偏心渦元強度與風量降低，而風扇所產生之噪音卻隨著角度增加而逐漸增加。(4)改變背板粗糙度對於風扇性能與噪音分析並無顯著的影響。

關鍵字

橫流扇 ； 計算流體力學 ； 聲壓位準 ； 偏心渦元 ； 葉片頻率單音

並列摘要

In order to improve the noise characteristics in the flow field of the cross flow fan (CFF), the present study adopted the CFD software-FLUENT to simulate the internal flow field of CFF and the sound pressure level by changing the blade type and wall roughness. Under the same of the rotational speed, the effects of different blade type and roughness on the fan performance and the characteristics of eccentric vortex were investigated. From the numerical results, it is found that: (1) the blade frequency tone for the fan can be significantly reduced by using the random pitch rotor instead of regular pitch rotor; (2) the fan performance decreases with the increase in the blade chord; (3) both blade frequency tone and volume flow rate decrease with the decrease in the blade angle; (4) changing the roughness has no apparent influence on the fan performance and the acoustic noise.

並列關鍵字

cross flow fan ； Computational Fluid Dynamics ； sound pressure level ； eccentric vortex ； blade passing tone

參考文獻

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