LAUSR

Abstract Real-gas (RG) thermodynamics is currently being employed in many fields of science and engineering ranging from energy production to planetary exploration to combustion and fluid mechanics. Particularly prediction of phase equilibrium, i.e. the condition at which two or more phases occur simultaneously in a multi-component mixture is of key importance because it represents a thermodynamic state that is more stable given that it occurs at a lower value of Gibbs free energy compared to the corresponding single phase state (i.e. only one phase exists). While the calculation of phase-equilibrium is a well-established tool, the determination of all the thermodynamic variables in the multi-phase mixture is relatively new and unexplored. In this work, we provide the complete analytical framework to compute multi-phase (we focus only on two phases for now), equilibrium properties in a generic multi-component system and demonstrate on mixtures with increasing level of complexity that approximate methods, sometimes used in the literature, provide inaccurate predictions, thus making the present model an important framework for all the simulation tools that employ RG thermodynamics with phase-equilibrium.