Package with dry air model that decouples pressure and temperature
This medium model is identical to
Modelica.Media.Air.SimpleAir, except the
equation d = p/(R*T)
has been replaced with
d/dStp = p/pStp
where
pStd
and dStp
are constants for a reference
temperature and density.
This new formulation often leads to smaller systems of nonlinear equations because pressure and temperature are decoupled, at the expense of accuracy.
As in Modelica.Media.Air.SimpleAir, the specific enthalpy h and specific internal energy u are only a function of temperature T and all other provided medium quantities are constant.
Extends from Buildings.Obsolete.Media.Interfaces.PartialSimpleIdealGasMedium (Medium model of Ideal gas with constant cp and cv. All other quantities, e.g., transport properties, are constant.).
Name | Description |
---|---|
fluidConstants=FluidConstants(iupacName={"simple air"}, casRegistryNumber={"not a real substance"}, chemicalFormula={"N2, O2"}, structureFormula={"N2, O2"}, molarMass=Modelica.Media.IdealGases.Common.SingleGasesData.N2.MM) | constant data for the fluid |
pStp=101325 | Pressure for which dStp is defined |
dStp=1.2 | Fluid density at pressure pStp |
BaseProperties | Basic medium properties |
setState_dTX | Return thermodynamic state from d, T, and X or Xi |
density | return density of ideal gas |
specificInternalEnergy | Return specific internal energy |
specificEntropy | Return specific entropy |
enthalpyOfCondensingGas | Enthalpy of steam per unit mass of steam |
saturationPressure | Return saturation pressure of condensing fluid |
Inherited | |
cp_const | Constant specific heat capacity at constant pressure |
cv_const=cp_const - R_gas | Constant specific heat capacity at constant volume |
R_gas | medium specific gas constant |
MM_const | Molar mass |
eta_const | Constant dynamic viscosity |
lambda_const | Constant thermal conductivity |
T_min | Minimum temperature valid for medium model |
T_max | Maximum temperature valid for medium model |
T0=reference_T | Zero enthalpy temperature |
ThermodynamicState | Thermodynamic state of ideal gas |
FluidConstants | fluid constants |
setState_pTX | Return thermodynamic state from p, T, and X or Xi |
setState_phX | Return thermodynamic state from p, h, and X or Xi |
setState_psX | Return thermodynamic state from p, s, and X or Xi |
setSmoothState | Return thermodynamic state so that it smoothly approximates: if x > 0 then state_a else state_b |
pressure | Return pressure of ideal gas |
temperature | Return temperature of ideal gas |
specificEnthalpy | Return specific enthalpy |
specificGibbsEnergy | Return specific Gibbs energy |
specificHelmholtzEnergy | Return specific Helmholtz energy |
dynamicViscosity | Return dynamic viscosity |
thermalConductivity | Return thermal conductivity |
specificHeatCapacityCp | Return specific heat capacity at constant pressure |
specificHeatCapacityCv | Return specific heat capacity at constant volume |
isentropicExponent | Return isentropic exponent |
velocityOfSound | Return velocity of sound |
specificEnthalpy_pTX | Return specific enthalpy 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 |
isentropicEnthalpy | Return isentropic enthalpy |
isobaricExpansionCoefficient | Returns overall the isobaric expansion coefficient beta |
isothermalCompressibility | Returns overall the isothermal compressibility factor |
density_derp_T | Returns the partial derivative of density with respect to pressure at constant temperature |
density_derT_p | Returns the partial derivative of density with respect to temperature at constant pressure |
density_derX | Returns the partial derivative of density with respect to mass fractions at constant pressure and temperature |
molarMass | Returns the molar mass of the medium |
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 |
density_ph | Return density from p and h |
temperature_ph | Return temperature from p and h |
pressure_dT | Return pressure from d and T |
specificEnthalpy_dT | Return specific enthalpy from d and T |
specificEnthalpy_ps | Return specific enthalpy from p and s |
temperature_ps | Return temperature from p and s |
density_ps | Return density from p and s |
specificEnthalpy_pT | Return specific enthalpy from p and T |
density_pT | Return density from p 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 |
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_h | Return density derivative w.r.t. pressure at const specific enthalpy |
density_derh_p | Return density derivative w.r.t. specific enthalpy at constant pressure |
specificEntropy_pTX | Return specific enthalpy from p, T, and X or Xi |
density_pTX | Return density from p, T, 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 |
constant FluidConstants[nS] fluidConstants= FluidConstants(iupacName={"simple air"}, casRegistryNumber={"not a real substance"}, chemicalFormula={"N2, O2"}, structureFormula={"N2, O2"}, molarMass=Modelica.Media.IdealGases.Common.SingleGasesData.N2.MM) "constant data for the fluid";
constant AbsolutePressure pStp = 101325 "Pressure for which dStp is defined";
constant Density dStp = 1.2 "Fluid density at pressure pStp";
Basic medium properties
Type | Name | Default | Description |
---|---|---|---|
Advanced | |||
Boolean | preferredMediumStates | false | = true if StateSelect.prefer shall be used for the independent property variables of the medium |
Return thermodynamic state from d, T, and X or Xi
Extends from Modelica.Icons.Function (Icon for functions).
Type | Name | Default | Description |
---|---|---|---|
Density | d | Density [kg/m3] | |
Temperature | T | Temperature [K] | |
MassFraction | X[:] | fill(0, 0) | Mass fractions [kg/kg] |
Type | Name | Description |
---|---|---|
ThermodynamicState | state |
return density of ideal gas
Extends from Modelica.Icons.Function (Icon for functions).
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Type | Name | Description |
---|---|---|
Density | d | Density [kg/m3] |
Return specific internal energy
Extends from Modelica.Icons.Function (Icon for functions).
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | thermodynamic state record |
Type | Name | Description |
---|---|---|
SpecificEnergy | u | Specific internal energy [J/kg] |
Return specific entropy
Extends from Modelica.Icons.Function (Icon for functions).
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Type | Name | Description |
---|---|---|
SpecificEntropy | s | Specific entropy [J/(kg.K)] |
Enthalpy of steam per unit mass of steam
0
.
Extends from Modelica.Icons.Function (Icon for functions).
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | Temperature [K] |
Type | Name | Description |
---|---|---|
SpecificEnthalpy | h | Steam enthalpy [J/kg] |
Return saturation pressure of condensing fluid
0
.
Extends from Modelica.Icons.Function (Icon for functions).
Type | Name | Default | Description |
---|---|---|---|
Temperature | Tsat | Saturation temperature [K] |
Type | Name | Description |
---|---|---|
AbsolutePressure | psat | Saturation pressure [Pa] |
Pressure as input signal connector
Mass fraction as input signal connector
Specific enthalpy as input signal connector