Transport properties of dilute binary mixtures with one tracer component

The transport properties of dilute binary gas mixtures with one tracer component are discussed. One finds that, except for the mutual diffusion coefficient, the transport coefficients in these mixtures are those of the excess component alone. The value of the mutual diffusion coefficient is obtained using the Chapman-Enskog method and the Sonine polynomial expansion and shown to lie within 1% of the exact value for all mass ratios μ in the tenth Enskog approximation. A comparison with earlier work on the limiting cases of the Lorentz gas (μ=0) and the Rayleigh model (μ=infinity) is made. (author)