A consistent use of the Lee–Kesler model

Accurate thermodynamic models of nonideal fluids are essential tools. Beyond the need for better predictive capabilities, their rigorous, thermodynamically-consistent implementation and use within property calculation workflows are a strict prerequisite to obtain physically meaningful and interpretable results. This article identifies inconsistencies in the original property calculation framework of the well-established Lee-Kesler model and proposes a thermodynamically-consistent, ready-to-use approach. In addition to the theoretical proof and discussion on consistency, a numerical analysis is presented to provide empirical evidence for the theoretical findings. The magnitude of errors are evaluated and depicted within a wide state space, using the example of CO 2 as modeled substance.