Thermal diffusion in polyatomic gas mixtures: methane-nitrogen and methane-carbon dioxide systems

The thermal diffusion factors alpha T of the gas mixtures CH4-N2 and CH4-CO2 have been measured as functions of temperature and composition by using the two-bulb method. The data have been analysed to assess the effects of inelastic collisions on thermal diffusion. The results show that for the system CH4-CO2, the thermal diffusion factor is significantly influenced by inelastic collisions. For CH4-N2 system no definite conclusion can be drawn regarding the influence of such effects.