离心泵蜗壳内压力脉动特性数值分析

Numerical analysis of pressure fluctuation in the volute of centrifugal pump

为揭示离心泵蜗壳流道内的压力脉动变化规律,采用雷诺时均方法(RANS),对3种工况下的离心泵内部三维非定常湍流流场进行数值计算,分析同一蜗壳断面不同位置以及沿蜗壳周向不同点的压力脉动特性。结果表明:蜗壳流道内具有非常明显的压力脉动,在各种工况下压力脉动的主频均是叶片通过频率;同一蜗壳断面上的压力脉动从蜗壳底部到蜗壳背面先减小后增大,蜗壳底部监测点的高频脉动成分较多;沿蜗壳周向,随着圆周角的增大,压力脉动减弱,隔舌附近压力脉动幅度最大,且高频脉动成分明显增加。

In order to reveal the variation laws of the pressure fluctuation in the volute of a centrifugal pump, the three- dimensional unsteady flow fields in the centrifugal pump under three different conditions are numerically solved by means of the Reynolds-averaged Navier-Stokes method. The pressure fluctuations at different points of the same section of the volute and different points along the circumferential direction of the volute are analyzed. The results show that the pressure fluctuations in the volute are obvious. The dominant frequencies under three conditions are found to be the ones that the blades pass. The pressure fluctuations at the same section decrease first and then increase from the bottom to the rear of the volute, and high-frequency fluctuations at the monitoring points on the bottom of the volute are evident. Along the circumferential direction, with the increase of circular angles, the pressure fluctuations decrease. The amplitude of pressure fluctuations is the largest near the tongue where high-frequency fluctuations dramatically increase.