Abstract: In order to study the influence of obstacles placed at different positions on the cavitation suppression effect of a centrifugal pump, a low specific speed centrifugal pump with a specific speed of 32 was used as the research model. A method was proposed to place obstacles on the back of the blade on the basis of obstacles placed in the middle of the blade working face. Based on the modified SST k-ω turbulence model and Zwart-Gerber-Belamri cavitation model, the study on the cavitation suppression effect and mechanism of the obstacle structure on the blade face and back simultaneously were conducted. The results show that the best cavitation suppression effect is achieved when the obstacle is placed at 35% of the radius of the impeller on the back of the blade. The head and efficiency of the prototype pump and the optimal scheme are compared and analyzed. In the design condition, the head decreases by 1.32%, the efficiency decreases by 1.45%, and the breaking point head increases by 21.57%. The volume of cavitation in the impeller was significantly reduced after the obstacles were placed, and the reduction in the severe stage of cavitation was as high as 42.20%. At the initial and developmental stages of cavitation, the main frequency amplitude of pressure in the inlet and impeller passage is reduced, causing a small disturbance at the outlet position. The placement of obstacles not only improves the cavitation performance of the centrifugal pump but also helps to reduce turbulent kinetic energy loss, making the internal flow field of the centrifugal pump more stable.

Key words: centrifugal pump, cavitation suppression, obstacle, numerical simulation, cavitation performance, turbulent kinetic energy