振动及空化是影响离心泵性能的重要因素。为了进一步优化流道，提高离心泵的性能，在保证离心泵其他参数不变的情况下，设计了3种不同叶片数叶轮。对3种离心泵进行全流道三维非定常湍流数值模拟，分析叶片数对离心泵性能的影响。结果显示：不同叶片数离心泵在两个监测点的压力脉动主频都是相对应的叶片通过频率，次频为叶片通过频率的倍频。叶片数的变化对隔舌处的压力脉动变化影响较大。随着叶片数的增加，离心泵的扬程逐渐增大，离心泵的效率变化比较复杂，当叶片数为5时，离心泵的效率最高。随着进口压力的不断降低，离心泵叶轮所受扭矩发生变化，在临界空化余量附近，泵扭矩发生。

Vibration and cavitation are important factors that affect the performance of centrifugal pump.In order to further optimize the flow passage of centrifugal pump and improve the performance,three kinds of impeller with different blade numbers are designed while rest geometric parameters of pump remain unchanged. Numerical simulation of three-dimensional unsteady turbulent flow in the whole flow passage of centrifugal pump with different number blades is carried out,to analyze the impact of blade number on the performance of low specific speed centrifugal pump.The results show that the pressure fluctuation occurs mainly at the blade frequency and its harmonics. The change in blade number has a great influence on the pressure fluctuation in the volute. With the increase in blade number,the head of the centrifugal pump gradually increases,while the efficiency change of centrifugal pump is more complicated,with highest efficiency at blade number Z=5. As the inlet pressure decreases,the torque of the impeller changes. In the vicinity of the critical cavitation,torque drops down steeply.

TK730.2

国家自然科学基金资助项目（51379179）；西华大学研究生创新基金项目（ycjj2016096）