Second-order corrections for transport properties of pure diatomic gases

Abstract

Second-order kinetic theory expressions involving either internal angular momentum or translational and rotational energies have been investigated for two potential energy surfaces for N₂ at temperatures between 77 and 1000 K. The largest correction is for the volume viscosity, where it is about 15% at 300 K and 20% at 600 K. For the thermal conductivity the angular-momentum related correction is approximately 1% and varies weakly with temperature, while the rotational and translational-energy-related correction increases with temperature, reaching approximately 1% at 1000 K. For the shear viscosity both corrections are no more than 0·5%. The Mason-Monchick approximation provides useful estimates of the energy-related corrections for the thermal conductivity and shear viscosity. Results calculated using the ab initio potential energy surface of Van der Avoird et al. agree better with experiment than those using the site-site potential of MacRury et al. for the shear viscosity and the thermal conductivity over a wide temperature range. However, for the volume viscosity the site-site potential yields results in somewhat better agreement with the observations.