Investigation on Thermal Conductivity and Viscosity of Thin Water Film by Molecular Dynamics Simulation

Abstract

This work provides a molecular dynamics simulation of the thermal conductivity and viscosity of thin water film. The results show that the average normal thermal conductivity and viscosity of thin water film is about an order of magnitude lower than those of bulk water, and they increase nonlinearly with the increase of thin film thickness. However, the viscosities at different sub-layers of a thin water film are apparently different. The density profiles at different positions of the thin water films are given to indicate their influence on the normal thermal conductivity and viscosity. The large increase of the viscosity and substantial decrease of the normal thermal conductivity in the near wall region of the substrate is influenced by the structural transition of thin water film because of its high density, which has prominent impact on the mean free path at the nanoscale. It provides a viable guidance for the mechanism study on the heat and mass transfer of an evaporating thin liquid film near the triple line.