.IDEAS.Media.Specialized.Air.PerfectGas

Model for air as a perfect gas

Information

This package contains a thermally perfect model of moist air.

A medium is called thermally perfect if

In addition, this medium model is calorically perfect, i.e., the specific heat capacities at constant pressure cp and constant volume cv are both constant (Bower 1998).

This medium uses the ideal gas law

ρ = p ⁄(R T),

where ρ is the density, p is the pressure, R is the gas constant and T is the temperature.

The enthalpy is computed using the convention that h=0 if T=0 °C and no water vapor is present.

Note that for typical building simulations, the media IDEAS.Media.Air should be used as it leads generally to faster simulation.

References

Bower, William B. A primer in fluid mechanics: Dynamics of flows in one space dimension. CRC Press. 1998.

Contents

Name Description
ThermodynamicState ThermodynamicState record for moist air
BaseProperties
Xsaturation Steam water mass fraction of saturation boundary in kg_water/kg_moistair
setState_pTX Thermodynamic state as function of p, T and composition X
setState_phX Thermodynamic state as function of p, h and composition X
setState_dTX Thermodynamic state as function of d, T and composition X
gasConstant Gas constant
saturationPressureLiquid Return saturation pressure of water as a function of temperature T in the range of 273.16 to 373.16 K
saturationPressureLiquid_der Time derivative of saturationPressureLiquid
sublimationPressureIce Saturation curve valid for 223.16 <= T <= 273.16. Outside of these limits a (less accurate) result is returned
sublimationPressureIce_der Derivative function for 'sublimationPressureIce'
saturationPressure Saturation curve valid for 223.16 <= T <= 373.16 (and slightly outside with less accuracy)
pressure Gas pressure
temperature Gas temperature
density Gas density
specificEntropy Specific entropy (liquid part neglected, mixing entropy included)
enthalpyOfVaporization Enthalpy of vaporization of water
HeatCapacityOfWater Specific heat capacity of water (liquid only) which is constant
enthalpyOfLiquid Enthalpy of liquid (per unit mass of liquid) which is linear in the temperature
der_enthalpyOfLiquid Temperature derivative of enthalpy of liquid per unit mass of liquid
enthalpyOfCondensingGas Enthalpy of steam per unit mass of steam
der_enthalpyOfCondensingGas Derivative of enthalpy of steam per unit mass of steam
enthalpyOfNonCondensingGas Enthalpy of non-condensing gas per unit mass of steam
der_enthalpyOfNonCondensingGas Derivative of enthalpy of non-condensing gas per unit mass of steam
enthalpyOfGas Enthalpy of gas mixture per unit mass of gas mixture
enthalpyOfDryAir Enthalpy of dry air per unit mass of dry air
der_enthalpyOfDryAir Derivative of enthalpy of dry air per unit mass of dry air
specificHeatCapacityCp Specific heat capacity of gas mixture at constant pressure
der_specificHeatCapacityCp Derivative of specific heat capacity of gas mixture at constant pressure
specificHeatCapacityCv Specific heat capacity of gas mixture at constant volume
der_specificHeatCapacityCv Derivative of specific heat capacity of gas mixture at constant volume
dynamicViscosity dynamic viscosity of dry air
thermalConductivity Thermal conductivity of dry air as a polynomial in the temperature
specificEnthalpy Specific enthalpy
specificEnthalpy_pTX Specific enthalpy
specificInternalEnergy Specific internal energy
specificGibbsEnergy Specific Gibbs energy
specificHelmholtzEnergy Specific Helmholtz energy
temperature_phX Compute temperature from specific enthalpy and mass fraction

Revisions


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