Influence of hub-cutting impellers on energy loss in a high-speed centrifugal pump

Purpose Cutting the hub of the impeller is tried to reduce energy losses caused by unstable flow at the impeller outlet for the high-speed centrifugal pump. Different cutting angles have been investigated to look for the influence of the law on the internal flow and energy loss. Design/methodology/approach Four cutting schemes of 0°, 15°, 30° and 45° for the impeller hub are proposed and studied in this paper. The flow fields in high-speed centrifugal pumps with different impellers are analyzed by using the SST k-ω turbulence model, and the energy losses are evaluated by the entropy generation method. The accuracy of numerical simulation is verified by experiments. Findings The pressure drop near the impeller outlet, which is close to the inlet of the volute, has been significantly reduced after the modification, and the impeller now has a more uniform flow velocity and a higher Euler head. In addition, implementing hub cutting impellers in centrifugal pumps reduces energy loss. Under various flow conditions, the total entropy production of the pump with the modified impeller is lower than that of the prototype pump, indicating that the energy loss can be effectively inhibited. Research limitations/implications The results show that cutting the impeller hub can effectively improve the performance and restrain the energy loss for high-speed centrifugal pump. Originality/value It provides some reference for the modification and design of high-speed centrifugal pumps.