Study on Hydrophobic Properties Transformation of Texture Surface by Numerical Drop Impact Simulation

Droplet impact experiment is an important means to explore the fluid dynamics and super-hydrophobic surface properties of materials. In this study, the droplet dynamics are analyzed mainly based on the Cassie state and the Wenzel state. The VOF model is used for numerical simulation to investigate the mechanism of the droplet's impact on the textured surface and to introduce a simple and effective method to calculate Contact angle to show surface hydrophobicity. The simulation results show that the surface hydrophobicity can be effectively improved by designing different micro-texture on the hydrophilic surface. With the increase of the impact velocity, the steady-state contact angle of the textured surface is obviously reduced. In addition, by quantitatively studying the movement of droplets on the micro-textured surface, it is found that the steady-state contact angle is related to the minimum spreading diameter of the first droplet after impact, and the smaller the diameter is, the larger the contact angle is.