Simplified theoretical expressions for the transport properties of ionized gas mixtures are derived within the framework of the Chapman—Enskog—Burnett method. The properties of equilibrium partially ionized argon are then computed with these expressions and compared with values obtained with the exact theory. Agreement is satisfactory.

The electrical conductivity, translational and reactive thermal conductivity and viscosity have been computed for ionized argon in thermodynamic equilibrium at pressues from 0.001-1000 atm and temperatures to 35 000°K. Comparison of the values with experiments shows reasonable agreement.

Expressions are developed with the Chapman-Enskog-Burnett method for the third and fourth approximations to the thermal conductivity and the diffusion coefficients, and for the second approximation to the viscosity of multicomponent gas mixtures. Special forms of these expressions are then derived for application to ionized gas mixtures, in particular to the partially ionized gas. Convergence of the approximations is checked by computing the properties of fully ionized hydrogen and of several other mixtures where the molecules interact with inverse-power repulsive potentials. From the results for hydrogen, it is seen that at least the third approximation should be used for the thermal conductivity and thermal diffusion coefficient, and the second approximation for the electrical conductivity and viscosity of ionized gases. These results contrast with those for un-ionized gases where one lower level of approximation is generally adequate.