Example: calculation of viscosity and thermal conductivity for a dissociated CO₂ gas mixture

Transport coefficients were calculated for the case of LTE reacting CO₂ mixture (CO₂, CO, O₂, O, C) at pressure P=1 atm in the temperature range 300≤T≤4000 K. The following parameters for Lennard-Jones potential were used:

CO₂-CO₂:       e/k= 216 K,  d= 3.87 Angstrom;    O₂-O₂:    e/k= 107 K,  d= 3.47 Angstrom;

CO-CO:          e/k= 100 K,  d= 3.71 Angstrom;    O-O:        e/k= 107 K,  d= 3.05 Angstrom;

C-C:                e/k=  31 K,  d= 3.39 Angstrom.

The necessary non-diagonal values e_ij and d_ij were calculated using the conventional combination rules. Transport coefficients were calculated using the accurate formulae of the Chapman-Enskog method with account for higher approximations, e.g. x=2 for viscosity, x=4 for translational thermal conductivity.

In figures (a) and (b) the calculated (a) viscosity and (b) total thermal conductivity l=l^tr+l^int of CO2 are compared with the experimental and theoretical data. This comparison indicates that the results of calculations are accurate to within about 1.4% for T≤2000 K, the uncertainty is of 7% at T=3000 K and 17% at T=4000 K because of the use of the Lennard-Jones potential for all pairs of particles.