Comparison of the prediction power of 23 generalized equations of state: Part II — Parametric evaluation

Abstract

The parameters contained in the 23 generalized equations of state (EOSs) studied in the first part of this research have been evaluated in the current study in order to determine conditions at which they should not be used. At first, for the studied generic van der Waals (vdW)-type EOSs it has been illustrated that what kind of temperature-dependence for the parameters involved such as the co-volume leads to infinite or negative isochoric and isobaric heat capacities at high pressures and how large the pressures are at which negative heat capacities occur. In the next step, the temperature-dependence and limiting behavior of the attraction parameters applied in the studied generic vdW-type EOSs have been investigated. Furthermore, the dominant trend of the second Virial coefficient in terms of the temperature has been explored for a generic vdW-type EOS taking into account the temperature-dependence of the attraction parameter and the prediction power of the studied EOSs for the second Virial coefficient have been tested against the experimental data. Thereafter, some useful remarks about the constraints in the solution of the EOS and the critical reduced pressure-reduced volume isotherm predicted by the studied EOSs have been presented. Finally, the main parameters of the studied EOSs, namely the thermal cohesion function and the co-volume of the studied generic vdW-type EOSs together with the second and third Virial coefficients of the studied truncated Virial-type EOSs have been examined for anomalies caused by particular conditions of the variables used to define them, i.e. the characteristic properties and the reduced temperature.