To investigate into the influence of blade length on internal flow and performance of a low specific speed centrifugal pump, an impeller with 8 full-length blades is designed by updating a refere-nce impeller which has 4 full-length blades plus 4 splitters. The flow field in the pumps is calculated based on the time-averaged Navier-Stokes equation and the Spalart-Allmaras turbulence model, then the internal flow characteristics are obtained. At the same time, the pump performance is tested to validate the performance predicted. It is found that the circumferential velocity is greater than the radial velocity in the volute, and the latter increases slowly with increasing circumferential angle. At the design point, both the head and the efficiency of the impeller with 8 full-length blades are higher than those of the impeller with 4 full-length blades and 4 splitters. The numerical results show that the low pressure area at the inlet of the impeller with 8 full-length blades is larger than that of the impeller with splatters. There exist vortexes in the flow passages of both impellers, and the area covered by the vortexes in the impeller with 8 full-length blades is larger than that in the impeller with splitters. Experimental results have verified the correctness of the numerical computation.
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