Thermal diode in gas-filled nanogap with heterogeneous surfaces using nonequilibrium molecular dynamics simulation

Abstract

A thermal diode serves as a basic building block to design advanced thermal management systems in energy-saving applications. However, the main challenges of existing thermal diodes are poor steady-state performance, slow transient response, and/or extremely difficult manufacturing. In this study, the thermal diode is examined by employing an argon gas-filled nanogap with heterogeneous surfaces in the Knudsen regime, using nonequilibrium molecular dynamics simulation. The asymmetric gas pressure and thermal accommodation coefficients changes are found due to asymmetric adsorptions onto the heterogeneous nanogap with respect to the different temperature gradient directions, and these in turn result in the thermal diode. The maximum degree of diode (or rectification) is R-max similar to 7, at the effective gas-solid interaction ratio between the two surfaces of e* = 0.75. This work could pave the way to designing advanced thermal management systems such as thermal switches (transistors).