Effects of impeller trimming methods on performances of centrifugal pump

Impeller trimming can improve the hydrodynamic performances of the centrifugal pump and expand the application range of the pumps. However, most researches focus on single-impeller cutting method; the literature slightly lacks a comparison of the different impeller trimming methods, which is very important in deciding on an impeller trimming method. In this paper, by taking the centrifugal pump as the research object, the accuracy of computational fluid dynamics (CFD) was verified by comparing experimental results and those of the numerical simulation. On the basis of impeller straight trimming, miscut, and triangle trimming methods, a new unconventional parabolic impeller trimming method was put forward. In different trimming sizes and operating conditions, performance curves of four impeller trimming methods were compared to get several different trimming models. By researching the flow field of centrifugal pump, the change reasons of centrifugal pump's performance curves were further revealed. The turbulent kinetic energy distribution and pressure distribution of the four trimming methods at best efficiency points (BEPs) were compared. The results showed that impeller trimming can improve pressure distribution of the impeller outlet, decrease shaft power, and increase energy saving.