Numerical analysis of effect of bionic hydrofoil structure on cavitation suspension
ZHAO Weiguo1,2*, LIU Jinjing1, ZHANG Jiayu1, QIN Jiawei1
1. School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; 2. Key Laboratory of Fluid Machinery and System of Gansu Province, Lanzhou, Gansu 730050, China
Abstract:Cavitation will cause high frequency pulsation impact on the fluid machinery surface, which will degrade its dynamic performance. In order to improve the cavitation suspension performance of hydrofoil, the influence of surface bionic structure parameters on the cavitation suspension effect of hydrofoil was studied in this paper. SST-TM turbulence model and Zwart-Gerber-Belamri cavitation model are used to numerically simulate the cavitation flow field and hydrodynamic characteristics of bionic structure hydrofoil with different parameters. The influence of the chord wise position, width and angle of the bionic structure on the cavitation effect was explored, and the mechanism of cavitation suspension was initially revealed. The results show that when the chord wise position of the bionic structure is L=0.3c, the width is b=2 mm and the angle is θ=14°, the suspension effect is the most obvious. Compared with the prototype hydrofoil, the number of cavitation is reduced by 24%, the vibration frequency of hydrofoil is reduced by 23%, the lift-drag ratio is increased by 4.73%, and the thickness and strength of the reverse jet flow are significantly weakened. As the bionic structure approaches the tail, the cavitation area on the suction side decreases first and then increases, and the suppression effect is the most obvious when the bionic structure is set at the end of the cavity where the cavitation is fully developed. With the optimum width parameter, the volume number of cavitation is minimum, the minimum pressure coefficient increases obviously, and the lift-drag ratio is maximum. The increase of the bionic structure angle can better increase the pressure near the wall of the hydrofoil, but also cause the generation of vortex, and aggravate the instability of the flow field.