Unsteady nanoscale thermal transport across a solid-fluid interface

We simulate unsteady nanoscale thermal transport at a solid-fluid interface by placing cooler liquid-vapor Ar mixtures adjacent to warmer Fe walls. The equilibration of the system towards a uniform overall temperature is investigated using nonequilibrium molecular dynamics simulations from which the heat flux is also determined explicitly. The Ar–Fe intermolecular interactions induce the migration of fluid atoms into quasicrystalline interfacial layers adjacent to the walls, creating vacancies at the migration sites. This induces temperature discontinuities between the solidlike interfaces and their neighboring fluid molecules. The interfacial temperature difference and thus the heat flux decrease as the system equilibrates over time. The averaged interfacial thermal resistance $Rk,av$ decreases as the imposed wall temperature $Tw$ is increased, as $Rk,av∝Tw−4.8$⁠. The simulated temperature evolution deviates from an analytical continuum solution due to the overall system heterogeneity.