Molecular Dynamics Simulation of Heat Transport through Solid–Liquid Interface during Argon Droplet Evaporation on Heated Substrates

This paper presents a series of molecular dynamics simulations of the evaporating process of an argon droplet on heated substrates and the energy transport mechanism through the solid–liquid interface. Results indicate that the mass density through the liquid–vapor interface decreases sharply when the evaporation is in the steady state. Meanwhile, there is an adsorption layer in the form of clusters at the solid–liquid interface, which has a higher mass density than the droplet inside. Furthermore, the wetting property of the solid substrate is related to the system’s initial temperature and the solid–liquid potential energy parameter. The contact angle decreases with the increase of initial temperature and solid–liquid potential energy parameter. During the accelerated evaporation process, small part of energy transports into the liquid in the perpendicular direction to the solid–liquid interface and most of the energy transports along the parallel direction to the solid–liquid interface in the adsorption layer to the three-phase contact line. The heat-transfer process from the solid substrate to the droplet inside is hindered by the Kapitza resistance at the solid–liquid interface, no matter the solid substrate is hydrophilic or hydrophobic. Meanwhile, the Kapitza resistance gradually increases with the increase of the initial temperature and decreases with the increase of the solid–liquid energy parameter.