There is no built-in equation of state for Van der Waals or BWR fluids; real gases are generally modeled with Redlich-Kwong or other available variants of the Van der Waals equation. If the unavailable equations of state are specifically required, however, there are two workarounds for this issue:
1 .Create expressions for Density, Cp, Viscosity, and Thermal Conductivity. These can be regular CEL expressions or, if necessary, you can write a User CEL function (which can be used in an expression) in FORTRAN for more complex logic. If the models are very complicated and require an iterative solver or root finder, this approach is not always appropriate.
2. For more complex equations of state, the best approach is to create a Real Gas Properties file (.rgp) with an appropriate table of properties. The format and organization of the RGP file is outlined in our documentation.