大型轴流泵装置模型试验的压力脉动

为了研究轴流泵内部压力脉动在不同叶片安放角度和扬程下的变化规律及特性，结合南水北调某新建泵站，采用物理模型试验方法，在叶轮进口、叶轮出口和出水流道壁面上布置了3个压力脉动测点，通过改变模型泵的扬程进行试验，采集了转轮模型叶片安放角为±4°及0°的压力脉动信号，并进行了幅值和频谱分析．结果表明，叶轮进口处比叶轮出口处压力脉动大；随着叶片安放角度的增大，3个测点的压力脉动均有所增加，但在叶轮进口和叶轮出口，增加幅度不大。在小扬程工况下，压力脉动的频率值仍以叶片通过频率为主；在高扬程工况下，低于1倍叶片通过频率的低频脉动会随着流量的减小，幅值越来越大，并占据主导地位．

Pressure pulsation of model test in large-size axial-flow pump

In order to study the rules and characteristics of pressure fluctuation under different blade an- gle and head in an axial-flow pump, the method of physical model test was used to study a new pumping station in South-to-North water diversion. Three measuring points were arranged in impeller inlet, outlet and outlet conduit. By changing head of model pump, the pressure pulsation signals were collected for blade angle of ＋ 4° and 0°. The amplitude distribution and frequency was analysed. The test results show that pressure pulsation of impeller inlet responses more strongly than that of impeller outlet. The pulsation of the three measuring points are increased with blade angle increasing, but the changes are small both in impeller inlet and outlet. In condition of small head, the frequency of blades are dominant. In the condition of large water head, the pulsation whose frequency is smaller than blades frequency is dominant and its amplitude increase with the flow decreaseing.