立式轴流泵装置叶片区压力脉动数值分析

Numerical Analysis of Pressure Fluctuation of the Blade Region in Vertical Axial-?ow Pumping System

压力脉动是影响轴流泵装置安全稳定运行的重要因素之一,为明确轴流泵装置叶片区压力脉动的变化规律,基于CFD软件对立式轴流泵装置全流道进行三维非定常数值计算,获得了轴流泵装置叶轮和导叶体区域的压力脉动时域数据,分析了最优工况时各监测点压力脉动特性,以及3个特征监测点的压力脉动随流量的变化规律。结果表明:最优工况时,叶轮进口压力脉动幅值从轮缘到轮毂逐渐减小;叶轮出口压力脉动幅值从轮缘到轮毂先减小后增大;导叶体出口处的压力脉动幅值从轮缘到轮毂先增大后减小。叶轮进口轮缘处压力脉动幅值随流量增大而减小;叶轮出口轮缘处压力脉动幅值随流量增大先减小后增大;导叶体出口轮缘处压力脉动幅值随流量增大而减小。小流量工况时各监测点的压力脉动主频幅值均大于最优工况和大流量工况。计算结果为分析轴流泵安全稳定运行提供了参考。

The pressure fluctuation is one of the important factors affecting the safe and stable operation of axial-flow pumping system,in order to understand the change rules of pressure fluctuation of the blade region in axial flow pumping system,a threedimensional unsteady numerical simulation was carried out using CFD on the whole flow passage of the vertical axial-flow pumping system. The pressure fluctuation time-domain data of impeller and guide vanes of the axial-flow pumping system were obtained,the pressure pulsation characteristics of each monitoring point during the optimal operating conditions were analyzed,and change rules of pressure fluctuation with flow rate at three characteristic monitoring points were analyzed. The results show that under the optimal operating conditions,the pressure fluctuation amplitude at the inlet of the impeller gradually decreased from the rim to the hub;the pressure fluctuation amplitude at the outlet of the impeller first decreased and then increased from the rim to the hub;the pressure fluctuation amplitude at the outlet of the guide vane first increased and then decreased from the rim to the hub. The pressure fluctuation amplitude at the inlet of the impeller rim decreased with the increase of flow rate;the pressure fluctuation amplitude at the outlet of the impeller rim decreased first and then increased with the increase of flow rate;and the pressure fluctuation amplitude at the outlet of the guide vane rim decreased with the increase of flow rate. The main frequency amplitude of pressure fluctuation at all monitoring points under low flow condition was greater than the ones under optimal operating conditions and high flow condition. The calculation results provide a reference for further analysis of the safe and stable operation of axial flow pump.