Abstract In order to study effects of blade leading edge position on centrifugal pump performance and internal flow field characteristics, five impellers with different blade leading edge positions were designed based on the original impeller of a centrifugal pump, and three-dimensional steady flow fields in the entire flow passage of the pumps with these impellers were carried out based on the SST k-ω and Zwart cavitation models under water single-phase as well as water-sand two-phase flow conditions. The results demonstrate that the suction performance of the centrifugal pump can be improved when the blade leading edge position is moved towards the impeller eye. The reason for this is that for a low specific-speed centrifugal pump its blade leading edge position being moved towards the impeller eye can improve flow conditions, such as flow uniformization, fluid velocity decrease and pressure rise in the impeller inlet. When the edge position is altered in a certain range, the head and efficiency of the pump are affected little. However, if the edge position is extended too much to the impeller eye, the head will be declined considerably because the blades are subject to the impaired capacity of doing work. At the same flow rate, the increase of sand content can degrade the head and efficiency of the pump but also augment the number of cavitation nuclei, thus make the suction performance poor.
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