Equation of State for Thermodynamic Properties of Fluids.

Abstract

This equation of state was developed from PVT compressibility data on methane and ethane. The highly-constrained form originates on a given liquid-vapor coexistence boundary (described by equations for the vapor pressures and the orthobaric densities). It then requires only five least-squares coefficients, and ensures a qualitatively correct behavior of the P(ρ, T) surface and of its derivatives, especially about the critical point. This nonanalytic equation yields a maximum in the specific heats C _υ (ρ, T) a t the critical point.