Molecular Dynamics Simulation Study of Heat Transfer across Solid–fluid Interfaces in a Simple Model System

Abstract

Nanoscale heat transfer across a solid-fluid interface was investigated by molecular dynamics simulations. The studied system consists of a fluid confined between two parallel plane atomistic walls. There is no convection. Both the fluid and the solid were modeled with the Lennard-Jones truncated and shifted potential. The following parameters were varied systematically: strength of solid-fluid and solid-solid interaction, mass of solid particles, temperature difference between fluid and solid, fluid temperature, fluid density, and channel width. From the simulation results, numbers for the Kapitza length LK were obtained, which characterizes the heat transfer resistance at the solid-fluid interface. A correlation of the results for the Kapitza length LK as a function of the studied variables was developed. A dimensionless number is introduced, the Kapitza interface number Ki, which describes the Kapitza effect in the stagnant fluid and is zero in the absence of the Kapitza effect. It is known that the heat transfer resistance at the interface is generally not influenced by convection, such that the results from the present work can also be used to describe heat transfer with convection in cases in which the Kapitza effect plays a role, or simply to assess the influence of the Kapitza resistance.