Study on Inlet Flow Field Structure and End-Wall Effect of Axial Flow Pump Impeller under Design Condition

The existing experimental technology cannot accurately and quantitatively measure the flow field structure and the wall boundary layer displacement effect in the axial flow pump. Based on SST k-ω turbulence model, a three-dimensional unsteady numerical simulation of the whole flow field of an axial flow pump was presented at the designed operating point to overcome the weakness of traditional measurement methods in measuring the flow field of the axial flow pump. The flow field structure of the axial flow pump inlet was studied quantitatively and the result was compared with the theoretical design value. It was found that there is an obvious impeller rotation effect and end-wall effect in the flow field of the axial flow pump inlet. The distribution law of the impeller inlet flow field and the crowding coefficient caused by the wall boundary layer were obtained. The pump inlet measurement point in the experiment and calculation domain inlet in the simulation should be kept at a distance of more than 0.5 D_s away from the impeller inlet to eliminate the influence of the impeller rotation effect. Through contrastive analysis, it was found that there is an obvious difference between the calculated value and the design value of the flow field structure due to the end-wall effect. The crowding coefficient should be taken into account when designing an axial flow pump. This study has certain reference significance for further understanding the flow field structure at the inlet of the axial flow pump impeller and improving the design theory of the axial flow pump.