超低扬程贯流泵模型试验的压力脉动研究

Research on the Pressure Pulsation of Model Tests of Super Low Head Tubular Pump

为了研究在不同扬程和不同叶片安放角下超低扬程贯流泵内压力脉动的变化规律,结合某泵站,采用物理模型试验的方法,在模型泵转轮进口和导叶出口处安放两个压力脉动测点,通过时域和频域分析,对超低扬程贯流泵内的压力脉动进行研究。结果表明:超低扬程贯流泵内的最大压力脉动发生在转轮与导叶之间;转轮进口处,低于设计扬程时的压力脉动变化比高扬程时大;导叶出口处,高于设计扬程时的压力脉动变化比低扬程时大;由空化现象可以看出,叶片安放角对贯流泵内的压力脉动有很大的影响作用;转轮进口和导叶出口处的压力脉动均以BPF为主;在高扬程工况下,以1~2倍固有频率的低频压力脉动幅值随扬程增加而增大,低扬程工况下未发现这种现象。

To study the pressure pulsation in the super low head tubular pump of different heads and different blade angles, by using a new pumping station and the method of physical model experimeut, the impeller inlet and the guide vane outlet arrangement of two pressure measuring points, the pressure pulsation in super low head tubular pump is studied through time domain analysis and frequency domain analysis. The resuhs show that the super low head tubular pump＇s maximum pressure pulsation oeeurs between the impeller and the guide vane. At the inlet of the impeller, the pressure pulsation is stronger than larger head whe,1 the head is smaller. At the guide vane outlet, the pressure pulsation is stronger than smaller head when the head is larger. It can be seen from the cavitation phenomenon that the blade setting angle has a great influence on the pressure pulsation. The main frequencies of pressure pulsation at impeller inlet and guide vane outlet are both blade passing frequeucy （BPF）. Under the couditiou of a large head, the low-frequency pressure pulsation with a frequency of between 1 and 2 times of rotation frequency is significantly larger, this phenomenon seldom occur under the low head conditions.