Relations between thermal conductivity and diffusion coefficients of pure and mixed polyatomic gases

Theoretical expressions for the thermal conductivity of pure polyatomic gases and mixtures of polyatomic gases are given in a form which involves only measurable quantities. Four such relations for pure gases have been investigated by analysing available experimental data for H 2 , N 2 , O 2 , CH 4 and CO 2 . Three relations applicable to mixtures are discussed. The formula based on Hirschfelder's theory has been tested in considerable detail for fifty-nine mixtures of thirteen different gas pairs with good overall success. The two other relations have also been discussed. Nevertheless, the work described here reveals that the relation obtained on the basis of Hirschfelder's theory is adequate for interpreting the existing binary thermal conductivity data, and more complicated theories do not show any appreciable improvement at least for these systems.