Numerical simulation of blade surface-fitted convex structure in centrifugal pump on cavitation suppression

A method that convex structure was attached to the pressure surfaces of blades was proposed to suppress cavitation development. A centrifugal pump with the specific speed of 32 was selected as the physical model. Shear stress transport (SST) k-ω turbulence model and the Zwart cavitation model were employed to simulate the unsteady cavitation flow in the centrifugal pump, and external characterization experiments were performed. Results show that the numerical simulated results are in a good agreement with the experimental results. After the convex structure is arranged, the head decreases within 1.5%, and the efficiency drops within 1%. While the convex structure changes the surface roughness of the blade, weakens the intensity of turbulent kinetic energy near the wall in the impeller passages, effectively reduces the distribution of cavitation bubble, and thus controls the development of cavitation. The cavity volume in the centrifugal pump is significantly reduced after the convex structure is arranged, and the maximum fraction reduction is 57.9%. After the convex structure is arranged, the amplitude of the main frequency of the pressure pulsation in the impeller channel is significantly reduced, showing a certain suppression on vibration, noise and wear caused by cavitation. © 2021, Editorial Board of Journal of Huazhong University of Science and Technology. All right reserved.