Visualization study of dynamic behavior of droplet impacting different wettability surface at normal-temperature

The dynamic behavior of droplet impact on a normal-temperature surface is widely studied in various fields, such as energy and chemical engineering, aerospace, and industrial production. The behavior characteristics directly affect the efficiency and stability of related industrial processes. Here, hydrophilic and superhydrophobic surfaces are used as the substrate, and high-speed cameras are employed to capture the complete dynamic process of droplets impacting the surfaces at different impact velocities and diameters. Based on the visualized images and combined with theoretical calculations, the influence of surface wettability, impact velocity, and droplet size on parameters such as droplet spreading factor, dimensionless height, secondary droplet mass fraction, and rebound energy is systematically explored. The dominant influencing factors and boundary triggering conditions of the dynamic processes of droplet spreading, contraction, rebound, and fragmentation are clarified. Furthermore, the experimental variables are uniformly characterized using the Weber number (We), and the influence of We on the above-mentioned dynamic parameters is deeply analyzed. The research results provide theoretical reference for the regulation and optimization of droplet impact behavior in related industrial fields.