.ThermofluidStream.Media.myMedia.Air.ReferenceAir.Air_Base

Information

This model calculates medium properties for air in the liquid, gas and two phase regions. Three variable pairs can be the independent variables of the model:

  1. Pressure p and specific enthalpy h are the most natural choice for general applications. This is the recommended choice for most general purpose applications.
  2. Pressure p and temperature T are the most natural choice for applications where air is always in the same phase (liquid or gas).
  3. Density d and temperature T are explicit variables of the Helmholtz function in the near-critical region and can be the best choice for applications with super-critical or near-critical states.

The following quantities are always computed:

Variable Unit Description
T K temperature
u J/kg specific internal energy
d kg/m^3 density
p Pa pressure
h J/kg specific enthalpy

In some cases additional medium properties are needed. A component that needs these optional properties has to call one of the functions listed in Modelica.Media.UsersGuide.MediumUsage.OptionalProperties and in Modelica.Media.UsersGuide.MediumUsage.TwoPhase.

Many further properties can be computed. Using the well-known Bridgman's Tables, all first partial derivatives of the standard thermodynamic variables can be computed easily.

Contents

NameDescription
 ThermodynamicStateThermodynamic state
 BasePropertiesBase properties of air
 density_phComputes density as a function of pressure and specific enthalpy
 temperature_phComputes temperature as a function of pressure and specific enthalpy
 temperature_psCompute temperature from pressure and specific enthalpy
 density_psComputes density as a function of pressure and specific enthalpy
 pressure_dTComputes pressure as a function of density and temperature
 specificEnthalpy_dTComputes specific enthalpy as a function of density and temperature
 specificEnthalpy_pTComputes specific enthalpy as a function of pressure and temperature
 specificEnthalpy_psComputes specific enthalpy as a function of pressure and temperature
 density_pTComputes density as a function of pressure and temperature
 dynamicViscosityReturn dynamic viscosity as a function of the thermodynamic state record
 thermalConductivityThermal conductivity of air
 pressureReturn pressure of ideal gas
 temperatureReturn temperature of ideal gas
 densityReturn density of ideal gas
 specificEnthalpyReturn specific enthalpy
 specificInternalEnergyReturn specific internal energy
 specificGibbsEnergyReturn specific Gibbs energy
 specificHelmholtzEnergyReturn specific Helmholtz energy
 specificEntropySpecific entropy of air
 specificHeatCapacityCpSpecific heat capacity at constant pressure of air
 specificHeatCapacityCvSpecific heat capacity at constant volume of air
 isentropicExponentReturn isentropic exponent
 isothermalCompressibilityIsothermal compressibility of air
 isobaricExpansionCoefficientIsobaric expansion coefficient of air
 velocityOfSoundReturn velocity of sound as a function of the thermodynamic state record
 density_derh_pDensity derivative by specific enthalpy
 density_derp_hDensity derivative by pressure
 setState_dTXReturn thermodynamic state of air as function of d and T
 setState_phXReturn thermodynamic state of air as function of p and h
 setState_psXReturn thermodynamic state of air as function of p and s
 setState_pTXReturn thermodynamic state of air as function of p and T
 setSmoothStateReturn thermodynamic state so that it smoothly approximates: if x > 0 then state_a else state_b
 isentropicEnthalpy
 molarMassReturn the molar mass of the medium

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