Thermodynamic Table Data

The .dat files contain property information for saturated, superheated, and sub-cooled fluids. They are located in the top-level folder of your Autodesk® CFD installation and you can view the contents with any text editor. For example, in Windows 7, ProgramData\Autodesk\CFD **.

Custom files

Using the default .dat files as guides, you can create your own custom thermodynamic table data files. Copy and edit one of the files included in your installation, or create a file from scratch. Once you have your custom file, you can select it for use with your fluid material.

Note: Your custom .dat files are not included with Share files. As a result, accompany your Share files with your custom .dat files so that they can be installed wherever the Share files are used.

File format

Each thermodynamic table file is divided into five sections:

Saturated

Each line in the Saturated section contains the following data:

temperature	pressure	vapor enthalpy	liquid enthalpy	vapor volume	liquid volume
°F	PSI	BTU/lbm	BTU/lbm	lbm/ft³	lbm/ft³

User care when solving for saturated flows due to the physically unstable nature of some flows, especially flows in which phase change occurs.

Superheated

For Superheated fluids, multiple temperature data points are supplied at each pressure. Each line contains the following data:

temperature	vapor volume	vapor enthalpy
°F	lbm/ft³	BTU/lbm

Note: For several of the fluids, there are more entries given for lower pressure values. As the distribution of pressure data is coarser for higher pressures, results tend to be more accurate for superheated fluids at lower pressures. If you require greater accuracy, add more data to the appropriate .dat file.

Sub-cooled Water

For Sub-cooled fluids, multiple temperature data points are supplied at each pressure. Each line contains the following data:

temperature	liquid volume	liquid enthalpy
°F	lbm/ft³	BTU/lbm

Vapor and Liquid Properties

Default values for viscosity, specific heat, and thermal conductivity are average values across the vapor and liquid portions of the saturated table, respectively. Each line contains the following data:

Viscosity	Conductivity	Specific Heat
Pa-s	W/m/°C³	J/kg/°C

Reference

Van Wylen, G. J., Sonntag, R. E., Fundamentals of Classical Thermodynamics, 2nd edition, John Wiley and Sons, Inc., 1973