Corresponding-state principle model for the correlation of temperature dependent difference of coexisted densities of refrigerants at equilibrium

Abstract

A simple and new correlation model based on the corresponding state principle is proposed for the difference of coexisted densities (DCD) of the saturated refrigerants fluids. It requires three physical properties as inputs. They are the critical temperature Tc, the minimal temperature Tmin at which data of the DCD is available in the NIST database, and the corresponding DCD value at Tmin. This proposed correlation has a simple analytical expression and includes only one adjustable parameter. It can accurately reproduce the DCD data in the NIST database in the temperature range from the triple point to the critical point with AAD values less than 1.92% for 47 out of 48 refrigerants considered. Large deviations only stand in a tiny temperature range very close to the critical point.