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:
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.
Extends from Modelica.Media.Interfaces.PartialPureSubstance (Base class for pure substances of one chemical substance).Name | Description |
---|---|
ph_explicit | True if explicit in pressure and specific enthalpy |
dT_explicit | True if explicit in density and temperature |
pT_explicit | True if explicit in pressure and temperature |
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 |
Inherited | |
setState_pT | Return thermodynamic state from p and T |
setState_ph | Return thermodynamic state from p and h |
setState_ps | Return thermodynamic state from p and s |
setState_dT | Return thermodynamic state from d and T |
ThermoStates | Enumeration type for independent variables |
mediumName="unusablePartialMedium" | Name of the medium |
substanceNames={mediumName} | Names of the mixture substances. Set substanceNames={mediumName} if only one substance. |
extraPropertiesNames=fill("", 0) | Names of the additional (extra) transported properties. Set extraPropertiesNames=fill("",0) if unused |
singleState | = true, if u and d are not a function of pressure |
reducedX=true | = true if medium contains the equation sum(X) = 1.0; set reducedX=true if only one substance (see docu for details) |
fixedX=false | = true if medium contains the equation X = reference_X |
reference_p=101325 | Reference pressure of Medium: default 1 atmosphere |
reference_T=298.15 | Reference temperature of Medium: default 25 deg Celsius |
reference_X=fill(1/nX, nX) | Default mass fractions of medium |
p_default=101325 | Default value for pressure of medium (for initialization) |
T_default=Modelica.SIunits.Conversions.from_degC(20) | Default value for temperature of medium (for initialization) |
h_default=specificEnthalpy_pTX(p_default, T_default, X_default) | Default value for specific enthalpy of medium (for initialization) |
X_default=reference_X | Default value for mass fractions of medium (for initialization) |
nS=size(substanceNames, 1) | Number of substances |
nX=nS | Number of mass fractions |
nXi=if fixedX then 0 else if reducedX then nS - 1 else nS | Number of structurally independent mass fractions (see docu for details) |
nC=size(extraPropertiesNames, 1) | Number of extra (outside of standard mass-balance) transported properties |
C_nominal=1.0e-6*ones(nC) | Default for the nominal values for the extra properties |
FluidConstants | Critical, triple, molecular and other standard data of fluid |
prandtlNumber | Return the Prandtl number |
heatCapacity_cp | Alias for deprecated name |
heatCapacity_cv | Alias for deprecated name |
beta | Alias for isobaricExpansionCoefficient for user convenience |
kappa | Alias of isothermalCompressibility for user convenience |
density_derp_T | Return density derivative w.r.t. pressure at const temperature |
density_derT_p | Return density derivative w.r.t. temperature at constant pressure |
density_derX | Return density derivative w.r.t. mass fraction |
specificEnthalpy_pTX | Return specific enthalpy from p, T, and X or Xi |
specificEntropy_pTX | Return specific enthalpy from p, T, and X or Xi |
density_pTX | Return density from p, T, and X or Xi |
temperature_phX | Return temperature from p, h, and X or Xi |
density_phX | Return density from p, h, and X or Xi |
temperature_psX | Return temperature from p,s, and X or Xi |
density_psX | Return density from p, s, and X or Xi |
specificEnthalpy_psX | Return specific enthalpy from p, s, and X or Xi |
MassFlowRate | Type for mass flow rate with medium specific attributes |
AbsolutePressure | Type for absolute pressure with medium specific attributes |
Density | Type for density with medium specific attributes |
DynamicViscosity | Type for dynamic viscosity with medium specific attributes |
EnthalpyFlowRate | Type for enthalpy flow rate with medium specific attributes |
MassFraction | Type for mass fraction with medium specific attributes |
MoleFraction | Type for mole fraction with medium specific attributes |
MolarMass | Type for molar mass with medium specific attributes |
MolarVolume | Type for molar volume with medium specific attributes |
IsentropicExponent | Type for isentropic exponent with medium specific attributes |
SpecificEnergy | Type for specific energy with medium specific attributes |
SpecificInternalEnergy | Type for specific internal energy with medium specific attributes |
SpecificEnthalpy | Type for specific enthalpy with medium specific attributes |
SpecificEntropy | Type for specific entropy with medium specific attributes |
SpecificHeatCapacity | Type for specific heat capacity with medium specific attributes |
SurfaceTension | Type for surface tension with medium specific attributes |
Temperature | Type for temperature with medium specific attributes |
ThermalConductivity | Type for thermal conductivity with medium specific attributes |
PrandtlNumber | Type for Prandtl number with medium specific attributes |
VelocityOfSound | Type for velocity of sound with medium specific attributes |
ExtraProperty | Type for unspecified, mass-specific property transported by flow |
CumulativeExtraProperty | Type for conserved integral of unspecified, mass specific property |
ExtraPropertyFlowRate | Type for flow rate of unspecified, mass-specific property |
IsobaricExpansionCoefficient | Type for isobaric expansion coefficient with medium specific attributes |
DipoleMoment | Type for dipole moment with medium specific attributes |
DerDensityByPressure | Type for partial derivative of density with respect to pressure with medium specific attributes |
DerDensityByEnthalpy | Type for partial derivative of density with respect to enthalpy with medium specific attributes |
DerEnthalpyByPressure | Type for partial derivative of enthalpy with respect to pressure with medium specific attributes |
DerDensityByTemperature | Type for partial derivative of density with respect to temperature with medium specific attributes |
DerTemperatureByPressure | Type for partial derivative of temperature with respect to pressure with medium specific attributes |
SaturationProperties | Saturation properties of two phase medium |
FluidLimits | Validity limits for fluid model |
FixedPhase | Phase of the fluid: 1 for 1-phase, 2 for two-phase, 0 for not known, e.g., interactive use |
Basic | The most basic version of a record used in several degrees of detail |
IdealGas | The ideal gas version of a record used in several degrees of detail |
TwoPhase | The two phase fluid version of a record used in several degrees of detail |
Name | Description |
---|---|
Advanced | |
preferredMediumStates | = true if StateSelect.prefer shall be used for the independent property variables of the medium |
Name | Description |
---|---|
p | Pressure [Pa] |
h | Specific enthalpy [J/kg] |
Name | Description |
---|---|
d | Density [kg/m3] |
Name | Description |
---|---|
p | Pressure [Pa] |
h | Specific enthalpy [J/kg] |
Name | Description |
---|---|
T | Temperature [K] |
Name | Description |
---|---|
p | Pressure [Pa] |
s | Specific entropy [J/(kg.K)] |
Name | Description |
---|---|
T | Temperature [K] |
Name | Description |
---|---|
p | Pressure [Pa] |
s | Specific entropy [J/(kg.K)] |
Name | Description |
---|---|
d | Density [kg/m3] |
Name | Description |
---|---|
d | Density [kg/m3] |
T | Temperature [K] |
Name | Description |
---|---|
p | Pressure [Pa] |
Name | Description |
---|---|
d | Density [kg/m3] |
T | Temperature [K] |
Name | Description |
---|---|
h | Specific enthalpy [J/kg] |
Name | Description |
---|---|
p | Pressure [Pa] |
T | Temperature [K] |
Name | Description |
---|---|
h | Specific enthalpy [J/kg] |
Name | Description |
---|---|
p | Pressure [Pa] |
s | Specific entropy [J/(kg.K)] |
Name | Description |
---|---|
h | Specific enthalpy [J/kg] |
Name | Description |
---|---|
p | Pressure [Pa] |
T | Temperature [K] |
Name | Description |
---|---|
d | Density [kg/m3] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
eta | Dynamic viscosity [Pa.s] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
lambda | Thermal conductivity [W/(m.K)] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
p | Pressure [Pa] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
T | Temperature [K] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
d | Density [kg/m3] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
h | Specific enthalpy [J/kg] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
u | Specific internal energy [J/kg] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
g | Specific Gibbs energy [J/kg] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
f | Specific Helmholtz energy [J/kg] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
s | Specific entropy [J/(kg.K)] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
cp | Specific heat capacity at constant pressure [J/(kg.K)] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
cv | Specific heat capacity at constant volume [J/(kg.K)] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
gamma | Isentropic exponent [1] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
kappa | Isothermal compressibility [1/Pa] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
beta | Isobaric expansion coefficient [1/K] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
a | Velocity of sound [m/s] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
ddhp | Density derivative w.r.t. specific enthalpy [kg.s2/m5] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
ddph | Density derivative w.r.t. pressure [s2/m2] |
Name | Description |
---|---|
d | Density [kg/m3] |
T | Temperature [K] |
X[:] | Mass fractions [kg/kg] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
p | Pressure [Pa] |
h | Specific enthalpy [J/kg] |
X[:] | Mass fractions [kg/kg] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
p | Pressure [Pa] |
s | Specific entropy [J/(kg.K)] |
X[:] | Mass fractions [kg/kg] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
p | Pressure [Pa] |
T | Temperature [K] |
X[:] | Mass fractions [kg/kg] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
x | m_flow or dp |
state_a | Thermodynamic state if x > 0 |
state_b | Thermodynamic state if x < 0 |
x_small | Smooth transition in the region -x_small < x < x_small |
Name | Description |
---|---|
state | Smooth thermodynamic state for all x (continuous and differentiable) |
Name | Description |
---|---|
p_downstream | Downstream pressure [Pa] |
refState | Reference state for entropy |
Name | Description |
---|---|
h_is | Isentropic enthalpy [J/kg] |
Name | Description |
---|---|
state | Thermodynamic state record |
Name | Description |
---|---|
MM | Mixture molar mass [kg/mol] |