Abstract:  Aiming at the problem that the selected head of the seawater circulating pump of a nuclear power plant was higher than the upper limit of the actual required head, a transformation method based on the multiparameter combined variant design of the impeller was proposed with 80% of the head of the rated working condition of the original model as the variant target. On the basis of the original model, 80% of the rated working point head of the original model was used as the variant target. Firstly, the outer diameter of the impeller, the installation angle of the blade outlet, the blade wrapping angle and the impeller outlet width were selected as the research factors, and the variant parameters were analyzed by orthogonal experimental design based on computational fluid dynamics (CFD) numerical simulation. Then, the relationship between each parameter and the performance of the seawater circulating pump was summarized, the variant scheme design was carried out, and the difference between the single-factor variant design and the multi-factor coupling variant design was compared, and the combined variant scheme of the main parameters was obtained. Finally, by adapting to other variant parameters, the variant combination was further optimized. The flow field characteristics of reducing the lift and improving the efficiency were analyzed, and the influence law of multiparameter combination on the performance of seawater circulating pump impeller was obtained.The results show that the head of the deformed seawater circulating pump is reduced by 18.57% and the efficiency is increased by 0.63%, which is respectively 7.52% and 3.27% higher than that when the head is reduced by only changing the outer diameter of the impeller and only changing the blade outlet angle.
Key words:  circulating pump; outer diameter of impeller; blade outlet angle; computational fluid dynamics (CFD); orthogonal test;numerical simulation; lift and efficiency of pump