Study on the influence of surface microstructure of hydrofoil on cavitation characteristics

Abstract

In order to better suppress the occurrence of cavitation, a hydrofoil model based on microjet structure and micro-wedge structure was established. The modified turbulence model shear stress transport (SST) k-ω is used to simulate the hydrofoil. By analyzing the vorticity distribution, flow field streamline, cavitation morphology, vortex structure and velocity vector distribution, the difference between the control effects of two kinds of airfoil surface microstructure on cavitation flow is studied, and the mechanism of micro wedge structure and micro jet structure on cavitation flow on airfoil surface is revealed. The results show that both microstructures show the suppression of vorticity distribution. The micro-wedge structure suppresses cavitation by affecting the turbulent kinetic energy of the near wall, the streamline vortex of the far wall and the vortex structure, accelerates the shedding and collapse of cavitation, and reduces the distribution of the low pressure region. When the chordwise position is 3.5 mm, the cavitation suppression effect is the most obvious. The microjet structure can affect the vortex motion on the far wall and hinder the upward development of the re-entrant jet. The larger the tangential jet ratio is, the stronger the jet intensity is. When the tangential jet ratio is 0.3 and 0.4, the suppression effect of the vortex motion is significant, the length of the low pressure distribution is smaller, and the shedding cavitation is accelerated from large scale to small scale.