立式自吸泵环形喷射孔比面积对其性能的影响

为了研究环形引流喷射对立式自吸泵性能的影响,以350WFB-1200-50型立式自吸泵为研究对象,采用RNG k-ε湍流模型和Zwart空化模型对不同环形喷射孔比面积下的立式自吸泵进行全流场数值计算.结果表明:环形引流喷射可明显提升叶轮进口压力,能有效改善泵的空化性能;引流流量会使叶轮进口处速度增大,导致泵的必需空化余量NPSHR增大,使泵的空化性能有所恶化;两者的共同作用下,泵的空化性能呈先变好后变差的趋势;随着环形喷射孔比面积k的增大,压水室出口处的泄漏量增大,导致泵的容积损失增大;泄漏流使压水室出口处产生较多旋涡,且射流对叶轮进口流线产生排挤,对主流造成较大影响,使泵的扬程和效率呈下降趋势;当环形喷射孔比面积k=0.25时,泵的汽蚀余量最小,相比于原模型,泵汽蚀余量减小了23%,扬程下降了2.1%,效率下降了2.5%.研究结果可为立式自吸泵优化设计提供一定参考.

Effect of annular jetting hole specific area on performance of vertical self-priming pump

To study the influence of annular drainage injection jet on performance of vertical self-priming pump, the vertical self-priming pump 350WFB-1200-50 was used as the research object, and the full flow field of vertical self-priming pump under different annular jetting hole specific areas was calculated using RNG k-ε turbulence model and the Zwart cavitation model. The research results show that the impeller inlet pressure and the cavitation performance of pump can be significantly improved by annular drainage injection jet. However, the NPSHR is increased resulted from an increase of impeller inlet speed which cased by the drainage flow, then the cavitation performance of pump deteriorated. Finally, the cavitation performance of pump increases first and then worse under the combined action of the two. As the specific area k of annular jetting hole increases, the volume loss of pump is increased resulted from an increase of leakage at the outlet of volute more vortexes at the outlet of volute and the impeller inlet streamline is crowded resulted from the jetting flow, which has a great influence on the mainstream, then the head and efficiency of pump declined. The vertical self-primimg pump net positive suction head reaches the minimum when the specific area k of annular jetting hole is 0.25, compared with the original model, the vertical self-primimg pump net positive suction head is reduced by 23%, the head is reduced by 2.1% and the efficiency is reduced by 2.5%. The research results can provide some reference for the optimization design of vertical self-priming pump.