含沙空化对轴流泵内涡量分布的影响

考虑空化与泥沙磨损的联合作用,采用SST k-ω湍流模型和ZGB空化模型,数值模拟研究不同空化程度下,轴流泵内涡量的变化过程。结果表明:涡量主要分布在叶片背面后部、出口边处以及叶片头部,工作面处涡量较小。相比清水而言,输送介质中含沙对叶轮和导叶内涡量的影响较大;随着粒径的增大,叶轮和导叶表面涡量随之增大,然而涡量的增大幅度不明显。低含沙量和小颗粒泥沙可以改善导叶内漩涡分布,减小漩涡强度。随着空化压力的降低,泵内涡量迅速增大,说明,粒径对泵内涡量的影响不大,含沙量和空化是引起涡量增大的主要原因。

Effect of Cavitation on Vorticity Distribution in Axial-flow Pump under Sand Conditions

Considering the combined effect of cavitation and sediment wear,the SST k-εturbulence model and ZGB cavitation model are used to numerically study the vorticity change process in an axial-flow pump to different cavitation degrees.The results show that the vorticity is mainly distributed at the rear of the blade back,the exit edge and the blade head,and the vorticity at the working surface is small.Sediment in the transmission medium,compared with water,has a more significant effect on the vorticity in the impeller and the guide vane.Low sediment concentration and small particles of sediment can improve the vortex distribution and reduce the vortex intensity in the guide vanes.The vorticity increases as the particle size grows,although not obviously.As the cavitation pressure decreases,the vorticity in the pump goes up rapidly.It shows that the particle size has little effect on the vorticity in an axial-flow pump.Sediment concentration and cavitation are the main causes of the increase in vorticity.