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

• Published in: International journal of quantum chemistry 2003, Vol.95 (2), p.79-87
• Main Authors: Da Costa Silva, Fabrício, Coelho, Luiz A. F., Tavares, Frederico W., Cardoso, Márcio J. E. M.
• Format: Article
• Language: English
• Subjects: effective diameter; molecular dynamics; perturbation theory; shear viscosity
• ISSN: 0020-7608; 1097-461X
• DOI: 10.1002/qua.10762

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%. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 95: 79–87, 2003