Evolution of the wetted zone and splash characteristics of droplet impacting on high-speed rotating hydrophobic surface

This study conducted experiments on the changes in the wetted zone and the splash characteristics during the impact of droplets on a rapidly rotating hydrophobic surface. Based on the experimental setup, the study systematically analyzed the effects of rotational linear velocity (vr) and the impact Weber number (We) on the morphology of the wetted zone, the separation modes of the tail liquid, and the growth patterns of the liquid finger. The study found that droplet impact on rotating hydrophobic surfaces exhibits four typical tail separation modes: “edge retraction,” “tearing,” and “fragmentation,” among which “edge retraction” forms a closed wetted zone and accounts for the largest proportion. In the variation of wetted zones, the circumferential wetted length Lc* is primarily driven by centrifugal force, whilst the radial length Lr* is significantly influenced by We; the two exhibit a certain degree of competition. Furthermore, the number of liquid fingers increases in direct proportion to vr and We, and is significantly stimulated by the synergistic effect of centrifugal force and initial kinetic energy. These findings reveal the underlying mechanisms governing the motion of wetted zones and the splashing of tail liquid on rotating hydrophobic surfaces, providing a theoretical basis for the design of anti-icing and anti-wear systems in relevant equipment.