Effect of molecular diameters on state-to-state transport properties: The shear viscosity coefficient

Abstract

Shear viscosity coefficient is calculated for both equilibrium and strongly non-equilibrium state-to-state vibrational distributions taking into account increasing diameters of vibrationally excited molecules. Under conditions of local thermal equilibrium, the effect of vibrational excitation on the shear viscosity coefficient is found to be negligible for temperatures below 5000K. For T>10000K, the contribution of excited states becomes important. Under non-equilibrium conditions characteristic for shock heated and supersonic expanding flows vibrational level populations deviate strongly from the Boltzmann distribution. Nevertheless, estimated coupled effect of molecular size and non-Boltzmann distributions on the shear viscosity coefficient is negligible.