Adsorption-controlled thermal switch using nonequilibrium molecular dynamics simulation

Abstract

A thermal switch is a system to control the heat transfer "on/off" for the desired functionalities, and this serves as a basic building block to design advanced thermal management systems in various applications including electronic packaging, waste heat recovery, cryogenic cooling, and new applications such as thermal computers. The existing thermal switches employ the macroscale mechanical-based, relatively slow transient "on/off" switch mechanisms, which may be challenging to provide solutions for micro/nanoscale applications. In this study, a fast and efficient thermal switch mechanism without having extra mechanical controlling system is demonstrated using gas-filled, heterogeneous nanogaps with asymmetric surface interactions in Knudsen regime. Argon gas atoms confined in metal-based solid surfaces are employed to predict the degree of thermal switch, S. Non-equilibrium molecular dynamics simulation is used to create the temperature gradient over the two nanogaps, and the maximum degree of thermal switch is S-max similar to 13, which results from the difference in adsorption-controlled thermal accommodation coefficient (TAC) and pressure between the two sides of the gaps.