Molecular dynamics study of effect of different wetting conditions on evaporation and rapid boiling of ultra-thin argon layer over platinum surface

摘要

Molecular dynamics simulations have been conducted to reveal the effect of solid-liquid interfacial wettability on the boiling phenomena of the thin liquid argon film placed over solid platinum wall. The three phase molecular system is comprised of solid platinum wall, liquid argon and argon vapor. Initially the three phase system is thermally equilibrated at 90K and after the attainment of equilibrium the temperature of solid platinum wall is suddenly increased which resembles ultrafast pulse heating. Two different degree of superheat have been considered to characterize the boiling phenomena, namely, evaporation for low degree of superheat and rapid or explosive boiling for high degree of superheat in which temperature of the wall was far above the critical temperature of argon. The solid-liquid interfacial wettability is varied to observe its effect on boiling and thus simulations are run for hydrophilic, hydrophobic and neutral surfaces. The simulation results show that surface wettability has a significant role on both cases of boiling phenomena. The nucleation of bubbles and formation of vapor films occurs more quickly for increased solid-liquid interfacial wettability. The study shows that hydrophilic surface is the most favorable surface condition for bubble nucleation.