Cubic Equations of State

Cubic equations of state (EOS) are fundamental tools in thermodynamics, particularly in modeling the pressure–volume–temperature (PVT) behavior of real fluids. Named for their cubic form in terms of the compressibility factor Z, these models strike a balance between computational simplicity and practical accuracy. Popular cubic EOS like Soave-Redlich-Kwong (SRK) and Peng-Robinson (PR) are widely used in both industry and academia for phase equilibrium calculations, property prediction, and chemical process design.

The primary advantage of cubic EOS lies in their analytical tractability and broad applicability. With only a few substance-specific parameters (typically critical properties and acentric factor), they are able to predict PVT properties.