Verification of Cavitation Damage Prevention of Mixed Flow Pump Impeller by Trailing Edge Shape Modification

Among mixed flow pumps used in various applications, movable-blade type mixed flow pumps have advantages, that is, maximizing the pump efficiency and the suction performance by adjusting the blade angle appropriate to the operating discharge flow rate. However, we have experienced the severe cavitation erosion in the impeller of this type of pump. In the present study, we firstly conducted the numerical flow simulation of CFD of the entire pump to examine if it can predict the occurrence of cavitation and the erosion location as well as pump performance. The results were compared with those of pump performance tests and visualization. In addition, on the basis of the pressure distribution obtained by numerical simulation of the impeller alone, we investigated the cause of erosion and the measures to avoid the erosion. Finally, it was reported that the new impeller reflecting the findings was confirmed to be successful; the erosion was avoided as expected.