On the evaporation rate of ultra-thin liquid film at the nanostructured surface: A molecular dynamics study

Molecular dynamic (MD) simulations have been carried out to study the effect of the nanostructures on the evaporation rate of the ultra-thin liquid film at the solid surface. Simple Lennard-Jones (LJ) fluids are simulated as the ultra-thin liquid film in the non-equilibrium simulation system. The liquid film is confined in a nanochannel composed of two solid surfaces designed with nanostructures in a shape of molecular-scale unevenness. The potential function between solid and liquid molecules is represented by a modified LJ function to conduct the solid–liquid interfaces of different surface wettability. For the steady non-equilibrium MD simulation, the liquid film is subjected to the steady heat flux passing through the nanostructured surfaces. It is found that the interface thermal resistance decreases at the nanostructured surface and apparent heat transfer enhancement is achieved due to the surface area increment. For the unsteady non-equilibrium MD simulation, the vapor has been sandwiched between the liquid films in contact with the nanostructured surfaces of high and low temperature respectively. It is found that the evaporation rate of the ultra-thin liquid film has a larger value than that of the flat surface when the film thickness is larger than that of the adsorbed layer.