进口非均匀来流对离心泵失速特性的影响

Effect of non-uniform Inflow on stall characteristics in centrifugal pumps

离心泵在实际运行中,往往会出现进口流动不均匀的现象。该文为探究进口不均匀流速分布对离心泵叶轮内失速特性的影响,在50%设计流量工况下,采用CFD方法对离心泵进口周向和径向两种非均匀来流条件下的失速特性进行数值模拟,并将结果与均匀来流情况下进行对比。结果显示:在均匀入流条件下失速类型为"固定失速",失速团数目为3个;而进口非均匀流速分布对失速类型有显著的影响,在两种非均匀进流的影响下,叶轮内的失速类型均转变为"旋转失速",且压力脉动显著增强。在径向非均匀来流的作用下,叶轮受到的径向力会显著增大,且径向力方向会随着失速团的运动发展而不断变化,而周向非均匀来流对径向力的影响有限。

During operation of a centrifugal pump,there is usually a non-uniform inflow in the pump inlet.In order to study the effect of non-uniform inflow distribution on stall characteristics in centrifugal pumps,two kinds of non-uniform flow in circumference and radial direction are examined under the working condition of 50%design flow rate by CFD method in this paper.The results are compared with those in uniform inflow condition as well.A"stationary stall"phenomenon appears,with 3 stall cells in the impeller.However,under the influence of two kinds of non-uniform inflow,the stall types inside the impeller converted into"rotating stall",with the pressure fluctuation reinforced significantly.In the cases of are radial non-uniform inflow,the impeller will be subjected to significant radial forces,and the direction of radial forces will change with the motion of stall cells.However,the effect from non-uniform flow in circumference direction on impeller radial force is limited.