Computer simulation and equation of state study of the Boyle and inversion temperature of simple fluids

Abstract

A new equilibrium molecular dynamics procedure is proposed and tested for determining directly the Joule—Thompson inversion curve of model simulation fluids. This method has the advantage that the Joule—Thompson inversion temperature envelope does not need to come from a predetermined equation of state. We test the new simulation procedure for the Lennard-Jones (LJ) fluid and make comparisons with the predictions of a range of equations of state, both specific to the LJ fluid and also those of the van der Waals type. In particular, we test a new equation of state developed from the Redlich—Kwong equation of state but having a number of advantages, especially for the Joule—Thompson inversion curve. The simulation method is particularly effective in the dense fluid regime, having distinct advantages over the equation of states route. We also consider the Boyle temperature from the equation of state.