Viscosity of pure supercritical fluids

Abstract

In this work, we propose a model for representing the viscosity of supercritical pure fluids over a wide range of conditions. A given pure real fluid is represented as a Lennard-Jones (LJ) fluid having effective values of the LJ intermolecular potential parameters. The LJ fluid is actually a corresponding states fluid where the dimensionless variables have, as a distinguishing feature, a dependency on parameters meaningful at molecular level. We have paid special attention to the qualitative behavior of the model when used beyond the conditions of the supporting molecular LJ simulation data. The model is able to correlate the pure compound viscosity of real supercritical fluids over a wide range of conditions with average absolute-value relative deviations less than or equal to 7% in most cases. The correlation needs two adjustable parameters per pure compound.