Transport in simple dense fluids

Abstract

A transport theory for Lennard-Jones (LJ) fluids is described. The underlying mean-field kinetic theory models the LJ potential by adding a hard-sphere core to the attractive tail of the LJ potential. The transport coefficients discussed here — shear viscosity, thermal conductivity, and self-diffusion coefficient — exhibit Enskog-like forms, but now the radial distribution function (rdf) bears explicit dependence on the LJ tail as well as on the hard-sphere core. The hardsphere diameter is determined according to the well-known WCA method used in equilibrium statistical mechanics to mimic the LJ fluid. Hence the transport theory employs no adjustable parameters. Numerical results are compared to simulation and experimental results for many states, including saturated liquid, triple point, and dense gas. In general, a quantitatively accurate transport theory is obtained for the states considered. This represents improvement, both numerically and conceptually, over an earlier theory.