Gas-Phonon Interaction Model for Subcontinuum Thermal Transport Simulations

Subcontinuum thermal transport problems such as the contact thermal resistance of semiconductor-gas interactions may play an important role in micro/nano-scale devices. In present work, a gas-phonon interaction modeling approach is suggested based on Boltzmann transport equations. Verification has been conducted by comparisons with asymptotic analytical solutions as well as previously reported numerical results and experimental data. Thermal transpiration in nano-sized channels and thermal resistance of nano-sized constrictions has been studied using the current model Thermal transpiration is the main mechanism for temperature driven pumps in nano/micro-devices. In order to maintain higher temperature ratio between the two ends of the gas path (capillaries), the choice of membrane material is very important, and the gas-solid interaction must be understood. It is shown from the calculations that the temperature gradient, capillary geometry, gas/solid Knudsen conditions, and the gas/solid thermal conductivity ratio are all responsible for the over-all compression efficiency. Heat transfer across mesoscopic constrictions poses a similar gasphonon coupling problem. Simulation shows that the analytical solution applies to limiting cases where the gas gap can be taken as a thin-fihn insulator. However, the heat flux through the gas thermal path may become a significant contributor for smaller gas phase Knudsen conditions