KNOWN ISSUE: Problems with thermodynamic properties for real gas combustion materials (Class 3 Error)
For the materials with the Material Group set to 'Real Gas Combustion', the specific heat has a discontinuity when plotted against temperature, leading to errors in the enthalpy calculation. Also, there is a staircase pattern and discontinuity in the entropy when plotted against temperature.
This is due to bugs in the CFX-Solver, where some local variables are defined as Integer rather than Double Precision, and where there is also incorrect implementation of the table machinery.
There is no workaround.
ANSYS CFX Release 12.1. A custom executable for ANSYS CFX Release 12.0 is available on request.