Inter-stage flow characteristics analysis of a multistage centrifugal pump with symmetrical impeller arrangement

Low-specific-speed multistage pumps are widely used in the chemical, electric power, and other fields. The symmetrical impeller arrangement structure brings stability advantages for multistage centrifugal pumps, but its inadequate structural design causes high hydraulic losses. Therefore, this paper takes the vertical multistage centrifugal pump with a symmetrical impeller arrangement structure as the research object. Through unsteady numerical simulation and test verification, the effects of the inlet flow condition on the intra-stage flow characteristic differences are analyzed, indicating the optimization direction for the structural design of multistage centrifugal pumps. This research shows the influence mechanism of the matching difference between the blade profile and the inlet flow pattern caused by the variation of the inlet flow angle on the inter-stage flow characteristics difference. This research shows that the direct cause of the asymmetric flow phenomenon is the flow structure difference caused by the uneven pre-rotation at the inlet. Our results enhance the understanding of internal flow mechanisms in multistage pumps and provide a clear direction and theoretical basis for the structural optimization of multistage centrifugal pumps.