离心风机旋转失速状态下的噪声特性预估

Acoustic characteristics prediction of a stall centrifugal fan

基于Navier-Stokes方程和节流阀函数,对G4-73型离心通风机的吸力面旋转失速现象进行了三维非稳态数值模拟。结果表明:设计工况和失速先兆发生时叶轮中间截面的声功率级分布和相对速度场云图的具有相似性,呈接近中心对称分布;完全失速状态下,高噪区主要分布在部分叶轮流道,其分布和传播特性与失速团的分布位置、周向传播特性完全相同;旋转失速导致叶轮内噪声水平提高,叶轮内最大声功率级提高2～3 dB。预估叶轮内声场的分布特性,有助于达到预测风机声学性能的目的。

Based on the Navier-Stokes equation and the throttle valve function, 3D unsteady numerical simulation is carried out about the suction surface rotating stall of a G4-73 type centrifugal fan. The results show that it is similar that the distribution situation of acoustic power level and relative velocity of the middle of impeller section when design con- ditions or the stall inception occurs, which is close to the center of symmetric distribution. When it is complete stall conditions, high noise areas are mainly distributed in parts of impeller passages. Its distribution, propagation character- istics and circumferential spread properties almost the same as the stall cell, rotating stall causes the rise of impeller in- terior noise level, the maximum acoustic power level is increased by 2 - 3 dB. Prediction of acoustic characteristics in impeller contributed to the research of acoustic performance of centrifugal fans.