An one parameter model to predict shear viscosity of dense fluids

Abstract

In this work we are proposing a new density correction to correlate and to predict shear viscosity of dense fluids. The shear viscosity is calculated by means of the smooth hard sphere theory that employs a Chapman–Enskog equation corrected to high densities coupled with an effective hard sphere diameter from perturbation theory of liquids. The corrections for density effects were generated using molecular dynamics (MD) data recently published in the literature for very large systems in the whole range of density. The calculations involved simple as well as polyatomic fluids including refrigerants. According to our results there is strong evidence that the coupling parameter of the rough hard sphere theory does not play a role in correlating and predicting shear viscosity even for polyatomic fluids. Our model employed very simple algebraic expressions with one adjustable parameter and worked fairly in the sub and supercritical region. Also we studied the role of different effective hard sphere diameters in the shear viscosity. Comparisons were made with a recent model published in the literature and our results showed that at high densities the new density correction play a very important role.