線型式離心風機數值與實驗整合研究

An Integrated Numerical and Experimental Study of In-Line Centrifugal Fan

張全和(Chuan-Ho Chang)

指導教授 ： 黃博全

國立臺北科技大學/機電學院/冷凍空調工程系所/碩士(2010年)

摘要

線型離心風機是由離心葉輪及簡單形狀外殼所構成的風機。它有
著氣流方向直進直出的特性，此比傳統的離心式風機更有具優勢，操
作在相同出口風壓力下，其噪音值也比軸流風機小很多。由於少了傳
統離心風機的渦殼，所以風機整體體積縮小了不少，對於空間上的配
置可以更靈活方便。
本研究探討線型式離心式風機之產品性能，透過數值模擬技術－
計算流體力學來完成此工作。採用風機廠商提供之風機藍圖，一方面
進行實體製造，另一方面進行風機流場數值模擬，二者實驗數值與模
擬數值比對，確立所建立之風機性能數值模式準確可被接受後，再進
一步利用數值模擬軟體 CFDRC 進行風機各項運作方式的性能分析。研究過程針對以下四個幾何參數變化(1)入口錐位置(2)出口角度(3)導葉與葉輪間隙大小(4)出風口方位和數目流場模擬分析，探討其對線型式離心風機內部流場分佈的影響，期找出提昇風機效率的方法。
由實驗與模擬之研究結果顯示(1)修改入口錐深入葉輪的長度，當
長度剛好切齊風輪時其位置為最佳，降低了經由間隙回流至葉輪入口的洩漏氣流，可讓空氣均勻進入內部葉輪，維持風機之性能；(2)葉輪上葉片出口角度在接近 38 度時，減少出口氣流撞擊機殼壁面，可提升風機性能約 13%；(3)箱體適當的加入整流裝置，可以有效把撞擊機殼壁面的渦流再降低，風機性能可提升約 3~5%；(4)不同的出風方向會影響風機效率，採用右出風或左出風方向，風機效率比直線出風多出約 13%；當同時使用左、右二個出風方向時，效率可提升約至 16%，而同時使用左、右及直
線出風方向時，效率可提升約至19%。

關鍵字

線型式離心風機 ； 計算流體力學 ； 性能分析

並列摘要

The In-line centrifugal fan (IlCF) consists of traditional centrifugal impeller and
simple box casing. It not only has the better operating performance than the traditional
centrifugal fan due to the same flow direction for the inlet and outlet airflows, but also
has lower noise than the axial flow operating under same exit pressure. Due to the lack
of volute casing, the IlCF has the smaller bulk volume, which leads to more convenient
flexible installation under the limit of space.
The purpose of this study is to explore the operation performance of IlCF through
the numerical simulating technique-CFD (Computational Fluid Dynamics).The research
method in this study is first to build a IlCF hardware and then to simulate numerically
the flow field inside the IlCF according to the IlCF sample provided by fan
manufacturer. When the numerical results are in agreement with experimental data, this
numerical mode will be applied to simulate the operation performance of IlCF different
through commercial software CFDRC. The effect of variation in (1) the distances
iv
between inlet cone and impeller, (2) blade exit angle within the impeller, (3) the gap
between guide vanes and impeller, and (4) outflow directions on the flow field
distribution inside the IlCF are investigated.
The results show that (1) when the outlet of inlet cone is just located at the inlet
position of impeller, the airflow will flow into impeller uniformly due to the decrease in
the mount of airflow permeating into the impeller inlet, (2) when the blade exit angle
approaches 38 degree, the efficiency of IlCF performance can be enhanced up to 13%
due to the decrease of the energy loss caused by outflow impacting on the casing, (3)
The IlCF efficiency can be enhanced over 3~5% through the arrangement of guide vane
placed at the outlet of impeller, and (4) Compared to In-line case with one outlet, the
efficiency of IlCF will increase (a) 13% by using right or left outlet, (b) 16% by using
both right and left outlets at the same time, and (c) 19% by using right, front, and left outlet simultaneously.

並列關鍵字

In-line centrifugal fan ； CFD ； Performance analysis

參考文獻

[8] 李延青、陳來富、周雅文、胡銘道、翁凌家，“線型離心風機之開發研究”，

[9] 李延青，“線型離心風機加裝靜置導葉片之分析與設計”， 冷凍空調&能源科技期刊，58期， 2009， pp.46-52。

[17] Vasudeva, K. , Yagnesh, N. , “CFD Analysis on the Effect of Radial Gap on Impeller -Diffuser Flow Interaction as well as on the Flow Characteristics of A Centrifugal Fan”,International Journal of Rotating Machinery, Article ID 293508, 2009 , 8 pages.

[20] Su, S. P., Chen, S. H., Lee, L. C., and Hwang, T. Y., “The Use of CFD in Turbomachinery Applications,” Trans. AASRC, Vol. 32, No. 1, 2000, pp. 1-20.

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