Study on cavitation characteristics of a waterjet pump under off-design conditions

Abstract Water jet pump is widely used in power field, and ordinary axial impeller is the key component of energy conversion. Because of the existence of tip clearance, the tip leakage flow through the clearance is inevitably accompanied by energy loss. Taking the axial-flow water jet pump as the research object, the condition is that the pump runs under the condition of deviating from the design condition. Considering the influence of vortex and cavitation, the improved numerical model is used to simulate the internal flow field. SST-CC turbulence model considering rotation correction and modified Zwart cavitation model based on vortex identification correction are selected. The cavitation performance and Vortex characteristics under off-design conditions are analyzed. The results show that flow loss is mainly reflected in turbulence dissipation and wall dissipation, which the turbulence dissipation and wall dissipation of impeller section account for the largest proportion. Because the cavitation area of water jet pump is mainly concentrated in the impeller, the turbulent dissipation is mainly related to the characteristics of turbulence kinetic energy and turbulent vortex. The research results can provide an effective basis for the analysis and design of axial-flow water jet pump.