Shear viscosity calculated by perturbation theory and molecular dynamics for dense fluids

摘要

In this work, we propose a new model to calculate viscosity of dense fluids based on the reference part of the Weeks-Chandler-Andersen perturbation theory. The reference fluid intermolecular interactions are given by a repulsive soft-sphere potential. The viscosity is calculated by means of a Chapman-Enskog equation corrected to high densities coupled with a density- and temperature-dependent effective diameter. The viscosity is also calculated by molecular dynamics simulations in a wide range of temperatures and densities for fluids interacting by repulsive soft-spheres potential. These results, obtained from molecular dynamics, are used to optimize the parameters of the effective diameter equation. To compute the contribution due to attractive intermolecular interactions, we use a temperature-dependent term, obtained by the Stokes-Einstein relation and the results published by Straub (1992) for the self-diffusion coefficient. The proposed model correlated experimental viscosity data from literature with absolute deviations less than 4%. (C) 2003 Wiley Periodicals, Inc. [References: 33]