空化对多级液力透平叶片压力脉动影响的数值模拟

The Influence of Cavitation on Pressure Pulsation of Multistage Centrifugal Pump as Turbine Based on Numerical Simulation

为研究空化对多级离心泵作液力透平叶片压力脉动的影响,通过非定常数值计算多级液力透平整机,研究最优工况下末级叶轮中空泡形态变化,分析不同空化程度下末级叶轮叶片上压力脉动变化规律。结果表明:不同空化系数下多级离心泵作液力透平在末级叶轮内产生翼型空化和漩涡空化产生的不稳定流动,导致叶片各监测点的主频幅值都在下降,并且叶片尾缘附近(监测点S4,P3)下降趋势更为严重。

In order to study the effect of cavitation on the pressure pulsation of the blade of the multistage centrifugal pump as turbine,the unsteady numerical calculation of the multistage centrifugal pump as turbine was carried out to study the shape change of the hollow bubble of the final impeller under the optimal working condition,and the pressure pulsation on the blade of the final impeller under different cavitation degrees was analyzed.The results show that the unsteady flow caused by airfoil cavitation and vortex cavitation occurs in the final impeller under different cavitation coefficients,which results in the decrease of the main frequency amplitude at each monitoring point of the blade,and the decrease trend is more serious near the trailing edge of the blade(monitoring points S4 and P3).