叶片打孔对离心风机噪声的影响分析

对离心风机叶片进行打孔处理,分析叶片打孔位置对风机噪声的影响。首先在稳态流场的计算结果上加载宽频噪声模型,得到不同工况下离心风机蜗壳和叶片上噪声分布情况,然后在瞬态分析的基础上加载FW-H噪声模块,利用LES/FW-H匹配技术分析叶片打孔对离心风机的气动噪声特性及声压级的影响。研究结果表明:离心风机结构表面声压主要集中在集流器、蜗舌和叶轮处,随着转速的增加,最大声压级也相应升高,趋势为先加快后减缓;离心风机气动噪声的频率主要集中在低中频段,且降低速度较快,在高频段则趋于平稳。与风机原模型相比,叶轮前端和中间打孔能够有效地降低噪声,噪声分别下降了4 dB和1 dB,后端打孔则会导致噪声升高。

Analysis of the Effect of Blade Punching on the Centrifugal Fan Noise

The centrifugal fan blades are perforated, and the impact of the blade perforation position on the fan noise is analyzed.Firstly, a broadband noise model is loaded on the steady-state flow field calculation results to obtain the noise distribution on the volute and blade of centrifugal fan under different conditions.Then load the FW-H noise module on the basis of transient analysis, and use LES/FW-H matching technology to analyze the effect of blade perforation on the aerodynamic noise characteristics and sound pressure level of the centrifugal fan.The results show that the surface sound pressure of the centrifugal fan structure is mainly concentrated at the collector, volute tongue and impeller. As the speed increases, the maximum sound pressure level rises accordingly, and the trend is to speed up and then slow down. The aerodynamic noise frequency of centrifugal fans is mainly concentrated in the low and mid frequency bands, the reduction speed is relatively fast, and it tends to be stable in the high frequency band.Compared with the original fan model, the noise can be effectively reduced by 4 dB and 1 dB by drilling in the front and middle of the impeller, and the noise will be increased by drilling at the back end.