We've been running quite some time with the standard CFX version where our real gas properties are prescribed in a RGP file.
This ran fine in CFX5.7.1. Now we started to use CFX10 using the same files and suddenly CFX cannot calculate the temperature field anymore (and hence density, and all temperature related variables).

A change in thedefault interpolation of tabulated thermodynamic data from 5.7 to 10 caused a lack of proper data for critical and triple point values to be crucial. The RGP data is really designed for coping with phase space trajectories close to, or crossing over, the phase boundary between gas and liquid. In order to be more robust 10 now uses the critical and triple point information for interpolation. Unfortunately Twister had set up RGP files as a convenient format to set up tabulated data for gas properties in 5.6 days when there was no alternative. They are only interested in the superheat region of phase space and so don't care about crticial and triple point values ... To return to 5.7 behaviour you can set the expert parameter 'prop interp option = 1'.

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