Heat Conduction Characteristic of Rarefied Gas in Nanochannel

Nonequilibrium molecular dynamics simulations is applied to investigate the simultaneous effect of rarefaction and wall force field on the heat conduction characteristics of nano-confined rarefied argon gas. The interactive thermal wall model is used to specify the desired temperature on the walls while the Irving–Kirkwood expression is implemented for calculating the heat flux. It is observed that as the temperature differences between the walls increases by lowering the temperature of the cold wall, the number of adsorbed gas atoms on the cold wall increases notably due to the increment in the residence time of the gas atoms. Consequently, the interfacial thermal resistance between the gas and the cold wall reduces which results in a reduction of the temperature jump. Meanwhile, the increase in the temperature of the hot wall leads to a reduction of the residence time of gas atoms in the near-wall region which decreases the number of absorbed gas atoms on the hot wall. This results in an increase in interfacial thermal resistance which leads to a higher temperature jump. It is observed that the bulk, wall force field and interface regions form approximately ۱۰%, ۴۵% and ۴۵% of the total thermal resistance, respectively. Furthermore, unlike the interfacial thermal resistance, the bulk and the wall force field thermal resistance are approximately independent of the implemented temperature difference.

کلیدواژه ها:

Temperature jump ، Thermal resistance ، Gas atoms distribution ، Molecular dynamics