离心风机旋转失速状态下的流体动力学特征

基于节流阀函数及Navier-Stokes方程,对电厂常用的G4-73型后向式离心风机的旋转失速现象进行了非定常数值模拟。结果表明,失速先兆呈现明显的模态波形,存在一个传播速度为62.9%wr的失速团。风机失速频率为14.15 Hz,与实验结果一致。分析旋转失速发生前后4个典型时刻的流场动力学特征,并研究失速团的周向传播规律,相对坐标系下失速团沿着与叶轮相反的旋转方向传播。失速区全压波动曲线的规律研究揭示了失速团的相对位置及传播速度是影响风机全压波动及其频率的根本原因。研究结果对旋转失速故障的预估及主动控制具有重要意义。

Dynamic Characteristics of Rotating Stall for Centrifugal Fans

The phenomenon of rotating stall for G4-73 backward-inclined centrifugal fan was numerically simulated using Navier-Stokes equations and the throttle valve function to calculate the characteristics of unsteady flow field.The results show that stall inception presents a significantly modal waveform,and propagation velocity of the stall cell is 62.9%wr.Stall frequency of the fan is 14.15 Hz that has a well agreement with experimental results.The characteristics at four typical moments before and after the appearance of rotating stall were analyzed.Circumference propagation law of the stall cell,and its rotating direction,which was opposite with the impeller in the relative coordinate system,were studied.The law of the full pressure fluctuation curve in the stall region reveals that full pressure fluctuation and its frequency are determined by the relative position and propagation velocity of the stall cell.The results have important significance in prediction and active control of rotating stall.