Heat Transfer on Walls in Molecular Dynamics Simulations: Modelling With Vibrating Reflective Walls

In simulations of micro channel cooling, the heat exchange from fluid to channel wall is an important aspect. Hence the heat exchange should be included in the model. Although numerically very expensive, it can be done by using a molecular wall. Numerically cheap implementations of a wall are the reflective wall and the thermal wall, and the combination of both, the diffusive-specular wall. In this paper we introduce the concept of a vibrating reflective wall as a boundary condition for molecular dynamics simulations. It is shown that the heat transfer with the vibrating reflective wall is the same as with a molecular wall, and that computation time is reduced greatly. As a competitive model, the diffusive-specular boundary condition is analyzed; it is shown that a good choice of parameters can give similar results in the same computation time, but the choice of parameters is not known a priori, therefore the vibrating reflective wall boundary condition is preferable.