The effects of blade number on inne

The effects of blade number on inner flow and characteristics of centrifugal pump were researched by using the methods of numerical simulation and experimental verification. The main research conclusions are below. (1) With the increase of the blade number, the limitation between blade and flow stream gets more obvious, the phenomenon of “jet and wake” in impeller did become unobvious，which is prominent in the flow channel against tongue of volute. It can be concluded that the increase of blade number is helpful to reduce the mixture loss of “jet” and “wake” in centrifugal pump. (2) The uniformity distributions of vapour in impeller channel became obvious with the increase of blade number. The clog phenomenon became obvious in flow passage of impeller with the more blade number. When the head of centrifugal pumps decreases 3%, the cavitation characteristics decrease evidently. (3) With the increase of blade number, the head of centrifugal pump grows all the time, the change regulations of efficiency and NPSHR are complex, but there is an optimum value for the best efficiency and cavitation characteristics, the optimum blade number of the model pump in this paper for efficiency is 7, 5 blades secondly and for cavitation characteristic is 5, 4 blades secondly, sothe model pump with the 5 blades has the best general characteristics. (4) With the increase of blade number, the area of low pressure region at the suction of blade inlet grows continuously, and the uniformity of static pressure distribution at screw section become worse and worse, while at diffusion section become better and better.