立式管道离心泵多工况压力脉动试验

为研究不同工况下立式管道离心泵内部压力脉动特性,文中采用动态压力传感器在模型泵进口弯管处、蜗壳隔舌附近、蜗壳扩散管处分别设置压力监测点,对0.6Q_d,1.0Q_d和1.4Q_d这3种流量下的压力脉动进行了测试,得到了压力脉动时域图、频域图和时频域图.试验结果表明:蜗壳隔舌附近的压力脉动信号波动最大.随着流量的增加,各监测点的压力脉动幅值先减小后增加.小流量和设计流量下,进口弯管处的压力脉动主频为2倍轴频,大流量下主频为轴频,幅值表现出强烈的波动特性.蜗壳隔舌附近的压力脉动主频均为叶频,幅值随流量增加而增大,在小流量和设计流量下高频处表现出较宽频段的波动性.蜗壳扩散管处的压力脉动在小流量和设计流量下主频为叶频,大流量下主频为轴频,轴频的幅值随流量增大而减小.

Experiment of pressure pulsation of vertical inline centrifugal pump under different working conditions

In order to research the pressure pulsation characteristics of vertical inline centrifugal pump under different conditions, the test was conducted by applying a dynamic frequency pressure sensor system under 4 different operating conditions, and the monitoring points of pressure were located on the inlet pipe and the volute. Both frequency and time-frequency characteristics were investigated in the experiment. The results show that the pressure pulsation at each monitoring point has a certain periodi-city. The amplitude of pulsation is the highest near the volute tongue. As the flow rate increases, the amplitude of each monitoring point first decreases and then increases. Except under 1.4Q_d condition, the dominant frequency of pressure pulsation at the inlet pipe is 2 times the shaft frequency, and the amplitude exhibits strong fluctuation characteristics. The dominant frequency of pressure pulsation at the volute tongue is of blade passing frequency, and its amplitude increases as the flow rate increases. It shows wide frequency volatility at high frequency under 0.6Q_d and 1.0Q_d. The dominant frequency of the pressure pulsation at the volute diffuser is of blade passing frequency under 0.6Q_d and 1.0Q_d, and the main frequency under overload conditions is of shaft frequency. The amplitude of shaft frequency decreases as the flow rate increases.