This model calculates medium properties for an ideal gas of a single substance, or for an ideal gas consisting of several substances where the mass fractions are fixed. Independent variables are temperature T and pressure p. Only density is a function of T and p. All other quantities are solely a function of T. The properties are valid in the range:
200 K ≤ T ≤ 6000 K
The following quantities are always computed:
Variable | Unit | Description |
h | J/kg | specific enthalpy h = h(T) |
u | J/kg | specific internal energy u = u(T) |
d | kg/m^3 | density d = d(p,T) |
For the other variables, see the functions in Modelica.Media.IdealGases.Common.SingleGasNasa. Note, dynamic viscosity and thermal conductivity are only provided for gases that use a data record from Modelica.Media.IdealGases.FluidData. Currently these are the following gases:
Ar C2H2_vinylidene C2H4 C2H5OH C2H6 C3H6_propylene C3H7OH C3H8 C4H8_1_butene C4H9OH C4H10_n_butane C5H10_1_pentene C5H12_n_pentane C6H6 C6H12_1_hexene C6H14_n_heptane C7H14_1_heptene C8H10_ethylbenz CH3OH CH4 CL2 CO CO2 F2 H2 H2O He N2 N2O NH3 NO O2 SO2 SO3
Sources for model and literature:
Original Data: Computer program for calculation of complex chemical
equilibrium compositions and applications. Part 1: Analysis
Document ID: 19950013764 N (95N20180) File Series: NASA Technical Reports
Report Number: NASA-RP-1311 E-8017 NAS 1.61:1311
Authors: Gordon, Sanford (NASA Lewis Research Center)
Mcbride, Bonnie J. (NASA Lewis Research Center)
Published: Oct 01, 1994.
Known limits of validity: The data is valid for temperatures between 200K and 6000K. A few of the data sets for monatomic gases have a discontinuous 1st derivative at 1000K, but this never caused problems so far.
This model has been copied from the ThermoFluid library and adapted to the Modelica.Media package.
Name | Description |
---|---|
thermodynamic state variables for ideal gases | |
Extended fluid constants | |
Base properties of ideal gas medium | |
Return thermodynamic state as function of p, T and composition X | |
Return thermodynamic state as function of p, h and composition X | |
Return thermodynamic state as function of p, s and composition X | |
Return thermodynamic state as function of d, T and composition X | |
return pressure of ideal gas | |
return temperature of ideal gas | |
return density of ideal gas | |
Return specific enthalpy | |
Return specific internal energy | |
Return specific entropy | |
Return specific Gibbs energy | |
Return specific Helmholtz energy | |
Return specific heat capacity at constant pressure | |
Compute specific heat capacity at constant volume from temperature and gas data | |
Return isentropic exponent | |
Return velocity of sound | |
approximate method of calculating h_is from upstream properties and downstream pressure | |
Return isentropic enthalpy | |
Returns overall the isobaric expansion coefficient beta | |
Returns overall the isothermal compressibility factor | |
Returns the partial derivative of density with respect to pressure at constant temperature | |
Returns the partial derivative of density with respect to temperature at constant pressure | |
Returns the partial derivative of density with respect to mass fractions at constant pressure and temperature | |
Compute specific heat capacity at constant pressure from temperature and gas data | |
Compute specific heat capacity at constant pressure, low T region | |
Compute specific heat capacity at constant pressure, low T region | |
Compute specific enthalpy from temperature and gas data; reference is decided by the refChoice input, or by the referenceChoice package constant by default | |
derivative function for h_T | |
Compute specific enthalpy, low T region; reference is decided by the refChoice input, or by the referenceChoice package constant by default | |
Compute specific enthalpy, low T region; reference is decided by the refChoice input, or by the referenceChoice package constant by default | |
Compute specific entropy from temperature and gas data | |
Compute specific entropy, low T region | |
Dynamic viscosity of low pressure gases | |
dynamic viscosity | |
Thermal conductivity of polyatomic gases(Eucken and Modified Eucken correlation) | |
thermal conductivity of gas | |
return the molar mass of the medium | |
Compute temperature from specific enthalpy | |
Compute temperature from pressure and specific entropy |