加装防涡圈的离心风机蜗壳内空气动力学特征和降噪研究

以G4-73No.8D型离心式风机为研究对象,采用CFD(computationalfluiddynamics)技术对风机蜗壳内的空气动力学特征进行了三维数值模拟,分析了旋涡的产生和演化过程以及旋涡噪声产生的机理,并在此基础上加装圆筒形和圆锥筒形2种防涡圈。加装防涡圈后的模拟结果显示,风机蜗壳内空气动力学特性得到明显改善,大尺度旋涡得以有效破碎。加装防涡圈后的噪声和频谱实验表明,风机的A声级和频谱噪声均有所下降,2种防涡圈对降低风机旋涡噪声是有效的;而且,在大尺度旋涡破碎和噪声降低方面,圆锥筒形均优于圆筒形防涡圈。

Investigation on Flow Dynamics and Decreasing Vortex Noise Inside Volute of Centrifugal Fan

The characteristics of three-dimension flow dynamics inside volute of G4-73No.8D centrifugal fan was modeled numerically with computational fluid dynamics(CFD)technique in present paper.The generation and evolution of vortex and its noise were investigated,and the cylinder-shape and cone-cylinder-shape anti-vortex rings were added separately.Numerical results with anti-vortex rings show that the large-scale vortexes are broken effectively and the flow fields inside fan are more uniform.Experimental results indicate A-sound level and spectrum noise are fallen off for refitted fan,and the anti-vortex rings have play important roles on decreasing vortex noise.The cone-cylinder-shape anti-vortex ring is more effective than cylinder-shape one based on breaking large-scale vortex and decreasing vortex noise.