The Cubic Equations of State (CuEOS) method uses the Cubic Equation of State for Pure Substance to calculate the density of liquid species, based on the same theory described in Real Gas Model in the Chemkin Theory Manual. Ansys Chemkin uses 5 CuEOS models: Van der Waals (VW), Redlich-Kwong (RK), Soave-Redlich-Kwong (SRK), Aungier-Redlich-Kwong (ARK), and Peng-Robison (PR).

The input format for this method in the surface/liquid kinetics file is: density = (CuEOS_<CuEOS_name>). The Cu_EOS_name is a required parameter and must be one of the implemented CuEOS models in Chemkin. For example: density=(CuEOS_PR) means the density of this liquid species would be calculated using the CuEOS method and the Peng-Robison model.