A Corresponding States Model for Generalized Engineering Equations of State

In this work, a four-parameter corresponding-states principle (CSP) model is proposed to generalize the universal technical Equation of State (EOS) developed in our previous work. This model is in the form of the Helmholtz free energy and takes the reduced density, reduced temperature, acentric factor and a polarity factor as variables. Compared to other generalized equations such as the one by Span and Wagner for nonpolar fluids, and by Platzer and Maurer and by Wilding and Rowley for polar fluids, the CSP model developed in this work shows good accuracy for the 22 nonpolar, polar, and associating fluids considered in this study and offers the flexibility to be extended to other fluids of industrial iInterest. In addition, the polarity factor used in this model has been successfully correlated from quantitative structure activity relationship (QSAR) molecular descriptors.