Contents - Index


NASA Ideal Gas and Condensed Species Data

 

Data for 1262 ideal gases have been incorporated into the EES property data base.   (The list of ideal gases is also displayed in the Function Information dialog when the NASA radio button is selected.)  Data for these fluids and for the fluids built into EES are provided with the EES property functions.  

 

These data were compiled by NASA as documented in:

 

Bonnie J. McBride, Michael J. Zehe, and Sanford Gordon

"NASA Glenn Coefficients for CalculatingThermodynamic Properties of Individual Species"

NASA/TP-2002-211556, Sept. 2002

http://www.grc.nasa.gov/WWW/CEAWeb/

 

The data consist of the specific heat, specific enthalpy, and specific entropy at standard pressure as a function of temperature.  The specific enthalpy is referenced to the elements having zero enthalpy at 25C.  The specific entropy is referenced to the pure fluid having zero entropy at 0 K, 1.013 bar, in accordance with the 3rd Law of Thermodynamics.

 

The NASA ideal gases can be used in EES property functions in exactly the same manner as for the built-in ideal gas fluid.  The unit system for which properties such as temperature and pressure must be supplied and properties are returned is specified with the Unit System dialog or the $UnitSystem directive.  The thermal properties are often most useful when expressed on a molar basis, which can be set with the choice of the unit system.  Examples uses of the NASA gases with the EES property routines are:

 

h_NH3=enthalpy(NH3,T=500 [K])

 

s_H=entropy(H,T=2000 [K],P=Po#)

 

One major difference between the built-in EES and NASA property data is that transport properties (viscosity and thermal conductivity) are not provided with the NASA ideal gases.  Also, critical properties and other related data, such as the acentric factor, triple point, heat of fusion, etc. are not available for the NASA ideal gases.   

 

 

The NASA ideal gas data were originally provided in the NASA external procedure.  This external procedure is still provided for backward compatibility and because it also provides data for hundreds of condensed substances that are not included in the NASA ideal gas data.  As an example, the following call provides thermodynamic property data for pure solid carbon.

 

Call NASA('C(gr)',300 [K]: cp, h, s)  {returns property information for solid carbon}

 

 

Information for using the NASA external procedure are aslo available with the Function Information dialog.  Click the External routines button.  Select the NASA entry and then click the  Function Info button.