Practical calculations of the equation of state of fluids and fluid mixtures using perturbation theory and related theories.

Abstract

The properties of a fluid are determined by short-range repulsive forces. The long-range attractive forces can be considered to be perturbations. Using these concepts, a perturbation theory of fluids is developed. In addition, the relationship of empirical equations of state to the perturbation theory is examined. The major weakness of most empirical equations is the use of the van der Waals free- volume term to represent the contributions of the repulsive forces. Replacement of this term by more satisfactory expressions results in better agreement with experiment. (A)