电站离心风机旋转失速的三维数值模拟

Tridimensional Numerical Simulation on Rotation Stall of Centrifugal Blower in Power Plant

基于标准k-ε湍流模型,对电站锅炉常用的G4-73No.8D型离心风机的旋转失速现象进行数值模拟。使用用户自定义函数(user-defined function,UDF)编制程序,在定常计算结果收敛的基础上在风机出口截面引入节流阀模型进行非定常计算,模拟离心风机内的旋转失速流动。计算结果表明,随着阀门开度的减小,风机逐渐进入失速区域,在靠近前盖板附近区域首先出现了逆流;随着流量的进一步减小,逆流从叶轮前盘位置逐渐扩散发展到后盘位置,直至充满整个流道。进入旋转失速状态后叶片表面压力的脉动最终会导致风机叶片的疲劳损坏,危害风机的安全经济运行。

. On the basis of standard k-ε overflow model, the paper numerically simulates on rotation stall of G4-73No. 8D cen- trifugal blower in power plant）. User-defined function （UDF） is used for programming and the throttle model located at the outlets of the fan is used for unsteady calculation which is based on the steady calculation that has been converged for the purpose of simulating rotation stall flow of centrifugal blower. The calculation shows that there appears back flow near the front cover and the fan gradually enters the stall area with the decreasing of the throttle opening; with the decreasing of the flow, back flow gradually spreads from the front cover to the rear cover until it fills the entire channel. With the fan runs into the rotating stall, the pressure fluctuations will eventually lead to blade fatigue and endanger the safe and economic operation of the fan.