KNOWN ISSUE: Incorrect results for Cv if using the IAPWS steam table library (Class 3 Error)
Using Cv (specific heat at constant volume) in an expression or user FORTRAN could give incorrect answers when using the IAPWS (steam table) library.
The CFX-Solver incorrectly calculates specific heat at constant volume when running the IAPWS (steam table) library for pressure and temperatures in region 2. Region 2 is the gas phase (dry steam) region, below the vapour pressure curve on a P vs T diagram. It spans the entire valid temperature range from 273.15 [K] to 1073.15 [K] and pressure range from the triple point to 100 [MPa].
Solutions computed by the CFX-Solver are in general not affected by the Cv calculations. However, any expressions or user FORTRAN which use Cv will be incorrect if the p or T values fall in region 2.
No workaround is currently available.
ANSYS CFX Release 12.1. A custom executable for ANSYS CFX 12.0 is available on request.