Thermal diffusion in gases

Results are presented of theoretical and experimental studies of thermal diffusion separation in gas mixtures under stationary and nonstationary conditions. Various methods used in describing thermal diffusion phenomena in gas mixtures are reviewed, and the principles underlying stationary and nonstationary methods for the experimental determination of the thermal diffusion constant are discussed. The discussion also covers the effect of thermal diffusion and diffusion heat conduction of the conductive and convective heat transfer. The contribution of the nonideality of gas mixture components to the process of thermal diffusion separation is determined. Experimental and calculated values of the thermal diffusion constant are presented for binary gas mixtures.