Transfer Characteristics Of Liquid Nanofilms By Molecular Dynamics Simulations

In the application field of microscale and nanoscale devices, the research on the transfer characteristics of nanofilm is of great significance. But the thickness of liquid nanofilm is always from several nanometers to several hundred nanometers. It is difficult to measure the thickness under laboratory conditions. In this paper, the molecular dynamics simulation method was used to simulate the evaporation process of nanofilm from the nanometer level. Factors such as temperature, wall potential parameters, the number of water molecules were considered to study on the evaporation behavior of water molecules such as the density distribution, the thickness of the vapor-liquid interface, etc. At the same time, the influence of wall potential parameters, temperature and wall roughness on the evaporation flux of nanofilm were studied by the method of non-equilibrium molecular dynamics simulation. As a result, for Pt-H2O system, the number of water molecules and the wall potential parameter have little effect on the thickness of the vapor-liquid interface. With the increase of simulated temperature, the thickness of vapor-liquid interface increases gradually and liquid density decreases. On the other hand, for Pt-Ar system, the simulation results show that the wall potential parameter and the wall roughness have different effects on the evaporation flux of the nanofilm.In addition, non-equilibrium molecular dynamics simulations were performed for the thermal transport in a nanochannel. The solid-solid interactions were modeled by the embedded atom method. The heat flux and interface resistance length were calculated by Green-Kubo method. It is found that there exist the relatively immobile solid-like layers adjacent to each solid wall surface due to being intensively attracted by solid atoms. The solid-liquid interface thermal resistance decreases with the increase of liquid wettability. The thermal resistance length of solid-liquid interface increases linearly with the temperature increment of solid surface. And surface roughness can reduce the interface thermal resistance.