Molecular dynamics simulations of energy accommodation coefficients for gas flows in nano-channels

作者：Sun Jun; Li Zhi Xin^*

来源：Molecular Simulation, 2009, 35(3): 228-233.

DOI：10.1080/08927020802395435

• accommodation coefficient
• molecular dynamics
• micro
• nano-scale gas flow

The energy accommodation coefficient (EAC) used in thermal boundary condition in micro- and nano-gas flows is reported to be always less than unity and greatly influenced by wall characteristics, for example, the wall temperature. A statistical EAC definition was described to calculate the EAC for thermal conduction in argon gas between two smooth platinum plates from two-dimensional non-equilibrium molecular dynamics simulations. The non-equilibrium EAC at the upper wall was calculated for different upper wall temperatures and a fixed bottom wall temperature. The equilibrium EAC at each temperature can then be extrapolated from a series of non-equilibrium EACs as the temperature difference between the two walls approaches zero. The analyses of the effects of wall temperature for various Knudsen number on non-equilibrium and equilibrium EACs show that, for a given lower bottom wall temperature, the non-equilibrium EAC at a high temperature wall increases with an increase in the wall temperature. For a given wall temperature difference, the non-equilibrium EAC increases with the increase in the wall temperatures. The equilibrium EAC also becomes larger at higher temperatures.

• 出版日期2009
• 单位清华大学