Droplet-particle collision dynamics: A molecular dynamics simulation

Molecular dynamics simulations are conducted to investigate the normal collision of the droplet-particle system. A wide range of influencing factors including the initial Weber number (30 ≤ We≤250), equilibrium contact angle (45° ≤ θ ≤ 145°), droplet-particle size ratio (0.5 ≤ Ω ≤ 2), temperature (293 K ≤ t ≤ 573 K) and composition are examined. Based on the atomic trajectories and kinetic energy dissipation during collision, temporal evolutions of evaporation molecules, dimensionless spreading diameter and film thickness are quantified and compared with available formulations. A total of seven collision outcomes are observed, which can be summarized in the regime map. Two types of disintegration, i.e. ligament-structured disintegration and conical-structured disintegration, exhibit distinct energy dissipation modes. An increasing We and a decreasing θ would lead to an increase in the maximum spreading diameter, while the minimum film thickness is less sensitive to θ. Additionally, evaporation during collisions is primarily influenced by the initial Weber number, because of the formation of satellite droplets.