New Correlation Functions for Viscosity Calculation of Gases Over Wide Temperature and Pressure Ranges

The viscosity of 14 supercritical gases over a wide temperature pressure range is calculated with a new correlation scheme. Highly accurate realistic iInteratomic potentials of the noble gases are used in the Chapman Enskog calculation of the zero-density viscosity and in the Rainwater Friend theory to determine the initial density dependence of the viscosity. At densities beyond the range of the theory, a variant of the residual viscosity is developed. It is shown that the temperature dependence of the residual viscosity function increases with the number of atoms in the molecule. By including this temperature dependence, the accuracy of the predicted results improves significantly. The accuracy of this method is within the experimental uncertainties.