螺旋离心泵叶轮区域漩涡空化的计算与分析

Evaluation and analysis of vortex cavitation in impeller region of screw centrifugal pumps

在一定工况下,螺旋离心泵内部由经过轮缘间隙的二次流所导致的漩涡涡核低压处会发生漩涡空化,由于螺旋离心泵流道宽阔,该漩涡空化可以得到充分发展.为了研究水力机械内部的漩涡空化特征,应用CFD软件对一台螺旋离心泵的空化特性进行数值模拟计算,分析螺旋离心泵内部发生漩涡空化时的流动规律,捕捉到了该泵内部漩涡空化的分布规律,发现漩涡空化的发生及发展受叶顶间隙压差和叶轮内部压力分布两个因素的共同影响.

Under certain operational condition,the vortex cavitation may take place at the low-pressure region of vortex nucleus in screw centrifugal pumps due to secondary flow in the gap at the impeller rim.This vortex cavitation will sufficiently develop because the flow passage in screw centrifugal pump is wide.In order to investigate the vortex cavitation characteristics inside the hydraulic machinery,numerical simulation and computation of cavitation characteristics of a screw centrifugal pump were performed by using the software CFD,the flow pattern inside the pump due to vortex cavitation was analyzed,and the distribution pattern of vortex cavitation inside the pump was caught.It was found that the generation and development of the vortex cavitation would be affected by both the pressure difference at the blade-top gap and the pressure distribution inside the impeller.