packageAir_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:

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.

Parameters

Contents

Name	Description
ThermodynamicState	Thermodynamic state
BaseProperties	Base properties of air
density_ph	Computes density as a function of pressure and specific enthalpy
temperature_ph	Computes temperature as a function of pressure and specific enthalpy
temperature_ps	Compute temperature from pressure and specific enthalpy
density_ps	Computes density as a function of pressure and specific enthalpy
pressure_dT	Computes pressure as a function of density and temperature
specificEnthalpy_dT	Computes specific enthalpy as a function of density and temperature
specificEnthalpy_pT	Computes specific enthalpy as a function of pressure and temperature
specificEnthalpy_ps	Computes specific enthalpy as a function of pressure and temperature
density_pT	Computes density as a function of pressure and temperature
dynamicViscosity	Return dynamic viscosity as a function of the thermodynamic state record
thermalConductivity	Thermal conductivity of air
pressure	Return pressure of ideal gas
temperature	Return temperature of ideal gas
density	Return density of ideal gas
specificEnthalpy	Return specific enthalpy
specificInternalEnergy	Return specific internal energy
specificGibbsEnergy	Return specific Gibbs energy
specificHelmholtzEnergy	Return specific Helmholtz energy
specificEntropy	Specific entropy of air
specificHeatCapacityCp	Specific heat capacity at constant pressure of air
specificHeatCapacityCv	Specific heat capacity at constant volume of air
isentropicExponent	Return isentropic exponent
isothermalCompressibility	Isothermal compressibility of air
isobaricExpansionCoefficient	Isobaric expansion coefficient of air
velocityOfSound	Return velocity of sound as a function of the thermodynamic state record
density_derh_p	Density derivative by specific enthalpy
density_derp_h	Density derivative by pressure
setState_dTX	Return thermodynamic state of air as function of d and T
setState_phX	Return thermodynamic state of air as function of p and h
setState_psX	Return thermodynamic state of air as function of p and s
setState_pTX	Return thermodynamic state of air as function of p and T
setSmoothState	Return thermodynamic state so that it smoothly approximates: if x > 0 then state_a else state_b
isentropicEnthalpy
molarMass	Return the molar mass of the medium