螺旋离心泵内不稳定漩涡空化对出口压力的影响

Influence of Unsteady Vortex Cavitation on Pump Outlet Pressure in A Screw Centrifugal Pump

为了深入研究水力机械内部的不稳定漩涡空化对出口压力的影响进行,应用CFD软件对一台螺旋离心泵进行了数值模拟计算,发现在一定工况下,螺旋离心泵内部由经过轮缘间隙的二次流所导致的漩涡涡核低压处会发生漩涡空化,并且该漩涡空化有一个初生-发展-分离的过程,并且发生该过程时螺旋离心泵扬程出现大幅下降,出口压力也有相应的不规则波动。

In order to study the influence of unsteady vortex cavitation on outlet pressure in hydraulic machinery,a numericalanalysis of unsteady vortex cavitation in screw centrifugal pump was presented using the computer fluid dynamic software CFD.It isfound that under a certain operation condition,the pressure at the core of vortex formed by tip leakage secondary flow is lower thanthe ambient pressure due to the centrifugal force on the vertical flow which results in vortex cavitation if the core pressure becomeslower than the vapor pressure in screw centrifugal pump.The process of inception、development and collapse of vortex cavitationwere obtained by the results as well.It is found that as the vortex cavitation occurs,the outlet pressure reduces considerably,andthe outlet pressure fluctuates irregularly.