Atomistic modelling of thin film argon evaporation over different solid surfaces at different wetting conditions

Abstract

In the present study, non-equilibrium molecular dynamics (MD) simulations have been performed to reveal the effect of solid-liquid interfacial wettability on the evaporation characteristics of thin liquid argon film placed over the flat solid surface. The atomistic model considered herein comprises of a three-phase simulation domain having a solid wall over which liquid argon and argon vapour co-exist. Initially, the system is thermally equilibrated at 90 K for a while after which rapid increase in the solid wall temperature induces a phase change process, i.e. evaporation. Both hydrophilic and hydrophobic wetting conditions of the solid surface have been considered at an evaporation temperature of 130 K for three different surface materials such as platinum, silver, and aluminium. The simulation results show that both the surface wettability and surface material have a significant role in phase transition phenomena of thin liquid film, particularly the surface wettability for the present system configuration. The thermal transport phenomena between the wall and liquid thin film have been studied thoroughly and discussed in terms of wall heat flux, evaporative mass flux, upper bound of maximum possible heat flux etc. The results obtained in the present MD simulation study are compared with the macroscopic predictions based on classical thermodynamics. Interestingly, a very good agreement has been found indicating that macroscopic thermodynamics approach can predict the characteristic of phase change phenomena of nanoscale thin liquid film.

Molecular dynamics approach to thin‐film liquid phase change phenomena on functionally gradient wettability surface

“…It can be observed that the temperature of Ar increases much quicker in the case of FGW surfaces with higher values of p. Also, in the hydrophilic case, the increase in temperature is the fastest. A number of previous studies [20] showed similar results that phase transition heat transfer on the hydrophilic surface occurs smoothly relative to the hydrophobic surface which is in agreement with our present study. This is due to the abundance of liquid Ar atoms adjacent to the solid hydrophilic wall that creates a continuous pathway for conduction heat transfer, which in turn increases the Ar temperature rapidly.…”

Atomic insights of thin‐film evaporation over biphilic surfaces: Effect of philic‐phobic patterning and wettability contrast

“…Due to higher solid‐liquid interaction, higher amount of thermal energy is transferred from the solid wall to the liquid Ar. Similar order of wall heat flux is observed previously by Hasan et al for surface A (case 1). For surface E maximum value of wall heat flux is the lowest.…”

Thin film liquid-vapor phase change phenomena over nano-porous substrates: A molecular dynamics perspective

“…[ 38 ] . Hasan et al [ 39 ] showed that cut-off radius beyond 4 (1.36 nm) has no significant impact on the simulations result, so, it was chosen as the cut-off radius in our study. Analytical tail correction was also not considered in our study to improve computational efficiency.…”