Measurement of apparent thermal diffusion factor of three-component (He-Ar-Kr) gas mixture.

Abstract

Apparent thermal diffusion factors of a three-component gas mixture composed of helium, argon, and krypton were determined by measuring local thermal diffusion factors. The dependence of the three binary thermal diffusion factors on composition and temperature were first studied over a wide range of experimental conditions and three empirical relations were obtained, as suggested by Laranjeira and Brown. Experiments showed that the relation of Van der Valk between apparent thermal diffusion factors was valid for any composition. Experimental results were in agreement with the calculations from Waldmann''s theory. The reciprocals of the ternary apparent thermal diffusion factors vary linearly with the concentration of the third component, except at large mixing ratios. By using this result and Van der Valk''s relations, the ternary apparent thermal diffusion factors can be estimated simply from the binary ones. The conditions in which a ternary apparent thermal diffusion factor is larger than a binary one were determined. Some ways of using the thermal diffusion factor to improve the separation of the mixture were obtained.