叶片数及分流叶片对离心泵流场和空化性能的影响

The Effect of Different Blade Numbers and Splitter Blades on Centrifugal Pump Flow and Cavitation Performance

对一低比转数离心泵模型,在叶片数分别为3个长叶片,3长3短(3/3)分流叶片,6个长叶片的三组叶轮方案下,对离心泵内部三维定常湍流空化流场进行数值模拟,计算不同叶轮方案下的外特性曲线和空化特性预测曲线。结果表明:在空化充分发展的工况下,叶片数少的叶轮方案扬程对NPSH降低较敏感;随着叶片数的降低,叶轮进口低压区面积减小,叶片的载荷增大。采用分流叶片,不仅减轻了叶轮进口处因叶片太多带来的排挤严重现象,而且提高了泵的扬程,离心泵空化性能也得到改善。随着叶片数的增加,叶片表面载荷逐渐减小,对于带分流叶片的叶轮,长叶片载荷在径向位置大约为分流叶片进口直径处下降曲线变陡。模拟结果能较好地反映不同叶轮方案下叶片数对离心泵内空化发生的影响,为空化特性的研究奠定了一定的理论基础。

Numerical simulations of the three-dimensional turbulent cavitation flow for a low specific speed centrifugal pump model whose blade numbers are 3long blades,3/3splitter blades and 6long blades are conducted.External characteristic curves and head performance of cavitation are included.The results show that the less blades the impeller had,the faster head declined with NPSH reducing in fully developed cavitation.With the reduction of the blade number,the impeller inlet low-pressure area decreases,and increases the blade load.Using the splitter blade,severe crowding phenomenon in impeller inlet is reduced and cavitation performance is improved.With the increase in blade number,the blade surface load decreases,The simulation results reflect the impact of cavitation in different impeller blades on a centrifugal pump better,It has laid a theoretical foundation for the study of cavitation characteristics.