Higher Approximations for the Transport Properties of Binary Gas Mixtures. II. Applications

Detailed numerical calculations are used to test the convergence of the higher approximations for the diffusion coefficient and thermal diffusion factor. The results show Kihara's second approximation to be the best to use and of sufficient accuracy, except for the thermal diffusion factor of mixtures with a heavy component in excess. For such a mixture both the Chapman-Cowling and the Kihara approximations are unreliable, and a new method is proposed for this case. The thermal diffusion of hydrogen-carbon dioxide mixtures is taken to illustrate the possible large errors resulting from use of inaccurate theoretical expressions. For precise work, the first approximations cannot in general be relied upon.