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IdealGasThermoProps

The calling protocol is

Call IdealGasThermoProps(F$,T,P,y[1..N]: MW, h, s, cp)

Inputs:
F$ a string constant or string variable that contains the names of 1 or more (up to 20) names of ideal gases that are contained in the EES property library.  The names of the gases are separated with a + sign, e.g., 'CH4+C3H8'
T the temperature in the units EES is configured to work in.
P the pressure in the units EES is configured to work in.  (Pressure is used only for calculation of specific entropy)
y[1..N] the mass or mole fractions of the gases represented by string F$.  The sum of the values of y must add to 1.0.  Supply mass fractions if EES is configured to work with specific properties on a mass basis.  Otherwise, supply mole fractions. 

Outputs:
MW The molar mass of the mixture in kg/kmol or lbm/lbmol
h the specific enthalpy of the mixture determined as the mole fraction-weighted average of the specific enthalpy of the gases in the mixture.  The units of h will be returned on a per unit mass basis if EES is configured to provide properties on a mass basis.  Otherwise the units of h will be returned on a molar basis.
s the specific entropy of the mixture determined as the mole fraction-weighted average of the specific entropy of the gases in the mixture plus the entropy change of mixing the gases.  The units of s will be returned on a per unit mass basis if EES is configured to provide properties on a mass basis.  Otherwise, the units of s will be returned on a molar basis.
cp The specific heat capacity of the gas mixture determined as the mole fraction-weighted average of the specific heat capacity of the gases in the mixture.

Example:

$UnitSystem SI Mass J K Pa
$VarInfo T Units = 'K'
$VarInfo P Units = 'Pa'
$VarInfo MW Units = 'kg/kmol'
$VarInfo h Units = 'J/kg'
$VarInfo s Units = 'J/kg-K'
$VarInfo cP Units = 'J/kg-K'

N = 3 
F$ = 'N2+O2+CO2'
T = 400 [K]
P = 100000 [Pa]
f[1] = 0.2
f[2] = 0.4
f[3] = 0.4

CALL IdealGasMixtureThermoProps(F$,T,P,f[1..N]:MW, h, s, cp)

{Solution:
MW = 34.81 [kg/kmol]
h = -3.481e6 [J/kg]
s = 6409 [J/kg-K]
cp = 960.8 [J/kg-K]
}

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