Initial density dependence of the viscosity of hydrogen and a corresponding states expression for high pressures

Abstract

Recently, the initial density dependence of gaseous viscosity and thermal conductivity, which was given by Rainwater–Friend, has been used to correct both viscosity and thermal conductivity by using accurate realistic potentials for gases. In this work, an accurate realistic Morse–Spline–Van der Waals (MSV) potential function for the hydrogen dimer is used to calculate the viscosity of hydrogen at low-densities on the basis of this theory. It is shown that in the case of hydrogen their theory works well up to densities of approximately 5 mol/l. We apply the theory to evaluate the viscosity of gaseous hydrogen over a wide temperature and pressure range. At high densities beyond the range of Rainwater–Friend theory, the excess viscosity was represented by a six-term correlation function similar to the noble gases. This correlation equation for the deviation viscosity of supercritical hydrogen is valid over the entire temperature range and pressures up to 200 MPa. The correlation represents experimental data within their uncertainty. By use of this deviation function, the viscosity of hydrogen can be calculated with mean (maximum) uncertainty of 0.76% (2.6%).