Study of wall wettability effects on cavitation bubble collapse using lattice Boltzmann method

Abstract

This study investigates the effects of wall wettability on cavitation bubble collapse using the pseudopotential lattice Boltzmann method with an appropriate external force term and wall contact angle boundary condition. The accuracy of the proposed numerical approach is verified by simulating a single-bubble collapse near a neutral wall. The result shows that the wettability condition of the wall has a significant effect on the forces exerted on cavitation bubbles. For a hydrophilic surface, there is a repulsive force between the surface and the bubble, whereas for a hydrophobic surface, the force is attractive. The wall wettability affects the evolution of the bubble shape, the maximum collapse pressure, the microjet velocity, and the total kinetic energy of the cavitation bubble during its collapse. Changing the wettability from hydrophobic to hydrophilic decreases the maximum pressure and microjet velocity but increases the cavitation bubble lifetime. Furthermore, the range of wall effects is smaller for a hydrophilic wall than for a hydrophobic wall.