Designing method of fish-friendly axial flow pump based on fish survival rate prediction

The invention provides a designing method of a fish-friendly axial flow pump based on fish survival rate prediction. A relation between a pump design parameter and the fish passing survival rate is predicted by adopting a mathematical model, and thus a fish-friendly design of an axial flow pump is guided. The mathematical model is mainly composed of the blade leading edge impact probability and the impact death rate; the impact probability is a ratio of the time that fishes pass through the cross section of passage of the blade leading edge and the time needed by an impeller rotating around a blade pitch; the impact death rate is relevant to the impact velocity, the fish length and the thickness of the blade leading edge; and the impact velocity adoptsa velocity component of a vertical leading edge. The fish-friendly axial flow pump design comprises the following steps: lowering the blade leading edge impact probability by adopting two blade impellers, lowering the impact death rate by adopting the blade leading edge with linear sweepforward protraction, and ensuring good hydraulic performance by virtue of airfoil parameter design. According to the designing method, a fish survival rate prediction model is high in goodness of fit to an experiment value, and the fish-friendly axial flow pump designed by guidance can greatly lower the fish death rate.