This package provides a full thermodynamic model of moist air including the fog region and temperatures below zero degC. The governing assumptions in this model are:
All extensive properties are expressed in terms of the total mass in order to comply with other media in this library. However, for moist air it is rather common to express the absolute humidity in terms of mass of dry air only, which has advantages when working with charts. In addition, care must be taken, when working with mass fractions with respect to total mass, that all properties refer to the same water content when being used in mathematical operations (which is always the case if based on dry air only). Therefore two absolute humidities are computed in the BaseProperties model: X denotes the absolute humidity in terms of the total mass while x denotes the absolute humidity per unit mass of dry air. In addition, the relative humidity phi is also computed.
At the triple point temperature of water of 0.01 °C or 273.16 K and a relative humidity greater than 1 fog may be present as liquid and as ice resulting in a specific enthalpy somewhere between those of the two isotherms for solid and liquid fog, respectively. For numerical reasons a coexisting mixture of 50% solid and 50% liquid fog is assumed in the fog region at the triple point in this model.
From the assumptions mentioned above it follows that the pressure should be in the region around atmospheric conditions or below (a few bars may still be fine though). Additionally a very high water content at low temperatures would yield incorrect densities, because the volume of the liquid or solid phase would not be negligible anymore. The model does not provide information on limits for water drop size in the fog region or transport information for the actual condensation or evaporation process in combination with surfaces. All excess water which is not in its vapour state is assumed to be still present in the air regarding its energy but not in terms of its spatial extent.
The thermodynamic model may be used for temperatures ranging from 190 ... 647 K. This holds for all functions unless otherwise stated in their description. However, although the model works at temperatures above the saturation temperature it is questionable to use the term "relative humidity" in this region. Please note, that although several functions compute pure water properties, they are designed to be used within the moist air medium model where properties are dominated by air and steam in their vapor states, and not for pure liquid water applications.
Several additional functions that are not needed to describe the thermodynamic system, but are required to model transport processes, like heat and mass transfer, may be called. They usually neglect the moisture influence unless otherwise stated.
The model's main area of application is all processes that involve moist air cooling under near atmospheric pressure with possible moisture condensation. This is the case in all domestic and industrial air conditioning applications. Another large domain of moist air applications covers all processes that deal with dehydration of bulk material using air as a transport medium. Engineering tasks involving moist air are often performed (or at least visualized) by using charts that contain all relevant thermodynamic data for a moist air system. These so called psychrometric charts can be generated from the medium properties in this package. The model PsychrometricData may be used for this purpose in order to obtain data for figures like those below (the plotting itself is not part of the model though).
Legend: blue - constant specific enthalpy, red - constant temperature, black - constant relative humidity
Extends from Modelica.Media.Interfaces.PartialCondensingGases (Base class for mixtures of condensing and non-condensing gases).
| Name | Description |
|---|---|
AbsolutePressure | Type for absolute pressure with medium specific attributes |
BaseProperties | Moist air base properties record |
Basic … | The most basic version of a record used in several degrees of detail |
beta | Alias for isobaricExpansionCoefficient for user convenience |
Choices … | |
CumulativeExtraProperty | Type for conserved integral of unspecified, mass specific property |
Density | Type for density with medium specific attributes |
density | Returns density of ideal gas as a function of the thermodynamic state record |
density_derh_p | |
density_derp_h | |
density_derp_T | |
density_derT_p | |
density_derX | |
density_phX | Return density from p, h, and X or Xi |
density_psX | Return density from p, s, and X or Xi |
density_pTX | Return density from p, T, and X or Xi |
DerDensityByEnthalpy | Type for partial derivative of density with respect to enthalpy with medium specific attributes |
DerDensityByPressure | Type for partial derivative of density with respect to pressure with medium specific attributes |
DerDensityByTemperature | Type for partial derivative of density with respect to temperature with medium specific attributes |
DerEnthalpyByPressure | Type for partial derivative of enthalpy with respect to pressure with medium specific attributes |
DerTemperatureByPressure | Type for partial derivative of temperature with respect to pressure with medium specific attributes |
DipoleMoment | Type for dipole moment with medium specific attributes |
DynamicViscosity | Type for dynamic viscosity with medium specific attributes |
dynamicViscosity | Return dynamic viscosity as a function of the thermodynamic state record, valid from 123.15 K to 1273.15 K |
EnthalpyFlowRate | Type for enthalpy flow rate with medium specific attributes |
enthalpyOfCondensingGas | Return specific enthalpy of steam as a function of temperature T |
enthalpyOfGas | Return specific enthalpy of gas (air and steam) as a function of temperature T and composition X |
enthalpyOfLiquid | Return enthalpy of liquid water as a function of temperature T(use enthalpyOfWater instead) |
enthalpyOfNonCondensingGas | Return specific enthalpy of dry air as a function of temperature T |
enthalpyOfVaporization | Return enthalpy of vaporization of water as a function of temperature T, 273.16 to 647.096 K |
enthalpyOfWater | Computes specific enthalpy of water (solid/liquid) near atmospheric pressure from temperature T |
enthalpyOfWater_der | Derivative function of enthalpyOfWater |
ExtraProperty | Type for unspecified, mass-specific property transported by flow |
ExtraPropertyFlowRate | Type for flow rate of unspecified, mass-specific property |
FixedPhase | Phase of the fluid: 1 for 1-phase, 2 for two-phase, 0 for not known, e.g., interactive use |
FluidConstants | |
FluidLimits | Validity limits for fluid model |
gasConstant | Return ideal gas constant as a function from thermodynamic state, only valid for phi<1 |
gasConstant_X | Return ideal gas constant as a function from composition X |
h_pTX | Return specific enthalpy of moist air as a function of pressure p, temperature T and composition X |
h_pTX_der | Derivative function of h_pTX |
heatCapacity_cp | Alias for deprecated name |
heatCapacity_cv | Alias for deprecated name |
HeatCapacityOfWater | Return specific heat capacity of water (liquid only) as a function of temperature T |
IdealGas … | The ideal gas version of a record used in several degrees of detail |
isentropicEnthalpy | Isentropic enthalpy (only valid for phi<1) |
isentropicEnthalpyApproximation | Approximate calculation of h_is from upstream properties, downstream pressure, gas part only |
IsentropicExponent | Type for isentropic exponent with medium specific attributes |
isentropicExponent | Return isentropic exponent (only for gas fraction!) |
IsobaricExpansionCoefficient | Type for isobaric expansion coefficient with medium specific attributes |
isobaricExpansionCoefficient | |
isothermalCompressibility | |
kappa | Alias of isothermalCompressibility for user convenience |
MassFlowRate | Type for mass flow rate with medium specific attributes |
MassFraction | Type for mass fraction with medium specific attributes |
massFraction_pTphi | Return steam mass fraction as a function of relative humidity phi and temperature T |
massToMoleFractions | Return mole fractions from mass fractions X |
MolarMass | Type for molar mass with medium specific attributes |
molarMass | |
MolarVolume | Type for molar volume with medium specific attributes |
MoleFraction | Type for mole fraction with medium specific attributes |
moleToMassFractions | Return mass fractions X from mole fractions |
PrandtlNumber | Type for Prandtl number with medium specific attributes |
prandtlNumber | Return the Prandtl number |
pressure | Returns pressure of ideal gas as a function of the thermodynamic state record |
relativeHumidity | Return relative humidity as a function of the thermodynamic state record |
relativeHumidity_pTX | Return relative humidity as a function of pressure p, temperature T and composition X |
s_pTX | Return specific entropy of moist air as a function of pressure p, temperature T and composition X (only valid for phi<1) |
s_pTX_der | Return specific entropy of moist air as a function of pressure p, temperature T and composition X (only valid for phi<1) |
saturationPressure | Return saturation pressure of water as a function of temperature T between 190 and 647.096 K |
saturationPressure_der | Derivative function for 'saturationPressure' |
saturationPressureLiquid | Return saturation pressure of water as a function of temperature T in the range of 273.16 to 647.096 K |
saturationPressureLiquid_der | Derivative function for 'saturationPressureLiquid' |
SaturationProperties | Saturation properties of two phase medium |
saturationTemperature | Return saturation temperature of water as a function of (partial) pressure p |
setSmoothState | Return thermodynamic state so that it smoothly approximates: if x > 0 then state_a else state_b |
setState_dTX | Return thermodynamic state as function of density d, temperature T and composition X |
setState_phX | Return thermodynamic state as function of pressure p, specific enthalpy h and composition X |
setState_psX | |
setState_pTX | Return thermodynamic state as function of pressure p, temperature T and composition X |
SpecificEnergy | Type for specific energy with medium specific attributes |
SpecificEnthalpy | Type for specific enthalpy with medium specific attributes |
specificEnthalpy | Return specific enthalpy of moist air as a function of the thermodynamic state record |
specificEnthalpy_psX | Return specific enthalpy from p, s, and X or Xi |
specificEnthalpy_pTX | Return specific enthalpy from p, T, and X or Xi |
SpecificEntropy | Type for specific entropy with medium specific attributes |
specificEntropy | Return specific entropy from thermodynamic state record, only valid for phi<1 |
specificEntropy_pTX | Return specific enthalpy from p, T, and X or Xi |
specificGibbsEnergy | Return specific Gibbs energy as a function of the thermodynamic state record, only valid for phi<1 |
SpecificHeatCapacity | Type for specific heat capacity with medium specific attributes |
specificHeatCapacityCp | Return specific heat capacity at constant pressure as a function of the thermodynamic state record |
specificHeatCapacityCv | Return specific heat capacity at constant volume as a function of the thermodynamic state record |
specificHelmholtzEnergy | Return specific Helmholtz energy as a function of the thermodynamic state record, only valid for phi<1 |
SpecificInternalEnergy | Type for specific internal energy with medium specific attributes |
specificInternalEnergy | Return specific internal energy of moist air as a function of the thermodynamic state record |
specificInternalEnergy_pTX | Return specific internal energy of moist air as a function of pressure p, temperature T and composition X |
specificInternalEnergy_pTX_der | Derivative function for specificInternalEnergy_pTX |
sublimationPressureIce | Return sublimation pressure of water as a function of temperature T between 190 and 273.16 K |
sublimationPressureIce_der | Derivative function for 'sublimationPressureIce' |
SurfaceTension | Type for surface tension with medium specific attributes |
T_phX | Return temperature as a function of pressure p, specific enthalpy h and composition X |
T_psX | Return temperature as a function of pressure p, specific entropy s and composition X |
Temperature | Type for temperature with medium specific attributes |
temperature | Return temperature of ideal gas as a function of the thermodynamic state record |
temperature_phX | Return temperature from p, h, and X or Xi |
temperature_psX | Return temperature from p,s, and X or Xi |
ThermalConductivity | Type for thermal conductivity with medium specific attributes |
thermalConductivity | Return thermal conductivity as a function of the thermodynamic state record, valid from 123.15 K to 1273.15 K |
ThermodynamicState | ThermodynamicState record for moist air |
TwoPhase … | The two phase fluid version of a record used in several degrees of detail |
Utilities … | Utility functions |
VelocityOfSound | Type for velocity of sound with medium specific attributes |
velocityOfSound | |
Xsaturation | Return absolute humidity per unit mass of moist air at saturation as a function of the thermodynamic state record |
xsaturation | Return absolute humidity per unit mass of dry air at saturation as a function of the thermodynamic state record |
xsaturation_pT | Return absolute humidity per unit mass of dry air at saturation as a function of pressure p and temperature T |
| Type | Name | Value | Description |
|---|---|---|---|
Integer | Air | 2 | Index of air (in substanceNames, massFractions X, etc.) |
ExtraProperty | C_default[nC] | fill(0, nC) | Default value for trace substances of medium (for initialization) |
Real | C_nominal[nC] | 1e-6 * ones(nC) | Default for the nominal values for the extra properties |
DataRecord | dryair | IdealGases.Common.SingleGasesData.Air | |
String | extraPropertiesNames[:] | fill("", 0) | Names of the additional (extra) transported properties. Set extraPropertiesNames=fill("",0) if unused |
Boolean | fixedX | false | = true if medium contains the equation X = reference_X |
FluidConstants | fluidConstants[nS] | {IdealGases.Common.FluidData.H2O, IdealGases.Common.FluidData.N2} | Constant data for the fluid |
SpecificEnthalpy | h_default | specificEnthalpy_pTX(p_default, T_default, X_default) | Default value for specific enthalpy of medium (for initialization) |
Real | k_mair | steam.MM / dryair.MM | Ratio of molar weights |
String | mediumName | "Moist air" | Name of the medium |
MolarMass | MMX[2] | {steam.MM, dryair.MM} | Molar masses of components |
final Integer | nC | size(extraPropertiesNames, 1) | Number of extra (outside of standard mass-balance) transported properties |
final Integer | nS | size(substanceNames, 1) | Number of substances |
Integer | nX | nS | Number of mass fractions |
Integer | nXi | if fixedX then 0 else if reducedX then nS - 1 else nS | Number of structurally independent mass fractions (see docu for details) |
AbsolutePressure | p_default | 101325 | Default value for pressure of medium (for initialization) |
final Boolean | reducedX | true | = true if medium contains the equation sum(X) = 1.0; set reducedX=true if only one substance (see docu for details) |
AbsolutePressure | reference_p | 101325 | Reference pressure of Medium: default 1 atmosphere |
Temperature | reference_T | 298.15 | Reference temperature of Medium: default 25 deg Celsius |
MassFraction | reference_X[nX] | {0.01, 0.99} | Default mass fractions of medium |
final Boolean | singleState | false | = true, if u and d are not a function of pressure |
DataRecord | steam | IdealGases.Common.SingleGasesData.H2O | |
String | substanceNames[:] | {"water", "air"} | Names of the mixture substances. Set substanceNames={mediumName} if only one substance. |
Temperature | T_default | Modelica.SIunits.Conversions.from_degC(20) | Default value for temperature of medium (for initialization) |
IndependentVariables | ThermoStates | Modelica.Media.Interfaces.Choices.IndependentVariables.pTX | Enumeration type for independent variables |
Integer | Water | 1 | Index of water (in substanceNames, massFractions X, etc.) |
MassFraction | X_default[nX] | reference_X | Default value for mass fractions of medium (for initialization) |
Extends from Modelica.SIunits.AbsolutePressure.
| Name | Value |
|---|---|
quantity | "Pressure" |
unit | "Pa" |
displayUnit | "bar" |
min | 0 |
max | 1e+8 |
start | 100000 |
nominal | 100000 |
Extends from Modelica.SIunits.Density.
| Name | Value |
|---|---|
quantity | "Density" |
unit | "kg/m3" |
displayUnit | "g/cm3" |
min | 0 |
max | 100000 |
start | 1 |
nominal | 1 |
Extends from Modelica.SIunits.DynamicViscosity.
| Name | Value |
|---|---|
quantity | "DynamicViscosity" |
unit | "Pa.s" |
min | 0 |
max | 1e+8 |
start | 0.001 |
nominal | 0.001 |
Extends from Modelica.SIunits.EnthalpyFlowRate.
| Name | Value |
|---|---|
quantity | "EnthalpyFlowRate" |
unit | "W" |
min | -1e+8 |
max | 1e+8 |
start | 0. |
nominal | 1000 |
Extends from Real.
| Name | Value |
|---|---|
quantity | "MassFraction" |
unit | "kg/kg" |
min | 0 |
max | 1 |
start | 0. |
nominal | 0.1 |
Extends from Real.
| Name | Value |
|---|---|
quantity | "MoleFraction" |
unit | "mol/mol" |
min | 0 |
max | 1 |
start | 0. |
nominal | 0.1 |
Extends from Modelica.SIunits.MolarMass.
| Name | Value |
|---|---|
quantity | "MolarMass" |
unit | "kg/mol" |
min | 0.001 |
max | 0.25 |
start | 0. |
nominal | 0.032 |
Extends from Modelica.SIunits.MolarVolume.
| Name | Value |
|---|---|
quantity | "MolarVolume" |
unit | "m3/mol" |
min | 1e-6 |
max | 1000000 |
start | 0. |
nominal | 1 |
Extends from Modelica.SIunits.RatioOfSpecificHeatCapacities.
| Name | Value |
|---|---|
quantity | "RatioOfSpecificHeatCapacities" |
unit | "1" |
min | 1 |
max | 500000 |
start | 1.2 |
nominal | 1.2 |
Extends from Modelica.SIunits.SpecificEnergy.
| Name | Value |
|---|---|
quantity | "SpecificEnergy" |
unit | "J/kg" |
min | -1e+8 |
max | 1e+8 |
start | 0. |
nominal | 1000000 |
Extends from Modelica.Media.Air.MoistAir.SpecificEnergy (Type for specific energy with medium specific attributes).
| Name | Value |
|---|---|
quantity | "SpecificEnergy" |
unit | "J/kg" |
min | -1e+8 |
max | 1e+8 |
start | 0. |
nominal | 1000000 |
Extends from Modelica.SIunits.SpecificEnthalpy.
| Name | Value |
|---|---|
quantity | "SpecificEnergy" |
unit | "J/kg" |
min | -1e+10 |
max | 1e+10 |
start | 0. |
nominal | 1000000 |
Extends from Modelica.SIunits.SpecificEntropy.
| Name | Value |
|---|---|
quantity | "SpecificEntropy" |
unit | "J/(kg.K)" |
min | -1e+7 |
max | 1e+7 |
start | 0. |
nominal | 1000 |
Extends from Modelica.SIunits.SpecificHeatCapacity.
| Name | Value |
|---|---|
quantity | "SpecificHeatCapacity" |
unit | "J/(kg.K)" |
min | 0 |
max | 1e+7 |
start | 1000 |
nominal | 1000 |
Extends from Modelica.SIunits.SurfaceTension.
| Name | Value |
|---|---|
quantity | "SurfaceTension" |
unit | "N/m" |
min | -Modelica.Constants.inf |
max | Modelica.Constants.inf |
start | 0. |
Extends from Modelica.SIunits.Temperature.
| Name | Value |
|---|---|
quantity | "ThermodynamicTemperature" |
unit | "K" |
displayUnit | "degC" |
min | 190 |
max | 647 |
start | 288.15 |
nominal | 300 |
Extends from Modelica.SIunits.ThermalConductivity.
| Name | Value |
|---|---|
quantity | "ThermalConductivity" |
unit | "W/(m.K)" |
min | 0 |
max | 500 |
start | 1 |
nominal | 1 |
Extends from Modelica.SIunits.PrandtlNumber.
| Name | Value |
|---|---|
quantity | "PrandtlNumber" |
unit | "1" |
min | 0.001 |
max | 100000 |
start | 0. |
nominal | 1 |
Extends from Modelica.SIunits.Velocity.
| Name | Value |
|---|---|
quantity | "Velocity" |
unit | "m/s" |
min | 0 |
max | 100000 |
start | 1000 |
nominal | 1000 |
Extends from Real.
| Name | Value |
|---|---|
min | 0 |
max | Modelica.Constants.inf |
start | 1 |
Extends from Real.
| Name | Value |
|---|---|
min | 0 |
max | Modelica.Constants.inf |
start | 1 |
Extends from Real.
| Name | Value |
|---|---|
unit | "kg/s" |
min | -Modelica.Constants.inf |
max | Modelica.Constants.inf |
start | 0. |
Extends from Real.
| Name | Value |
|---|---|
unit | "1/K" |
min | 0 |
max | 1e+8 |
start | 0. |
Extends from Real.
| Name | Value |
|---|---|
quantity | "ElectricDipoleMoment" |
unit | "debye" |
min | 0 |
max | 2 |
start | 0. |
Extends from Modelica.SIunits.DerDensityByPressure.
| Name | Value |
|---|---|
unit | "s2/m2" |
min | -Modelica.Constants.inf |
max | Modelica.Constants.inf |
start | 0. |
Extends from Modelica.SIunits.DerDensityByEnthalpy.
| Name | Value |
|---|---|
unit | "kg.s2/m5" |
min | -Modelica.Constants.inf |
max | Modelica.Constants.inf |
start | 0. |
Extends from Modelica.SIunits.DerEnthalpyByPressure.
| Name | Value |
|---|---|
unit | "J.m.s2/kg2" |
min | -Modelica.Constants.inf |
max | Modelica.Constants.inf |
start | 0. |
Extends from Modelica.SIunits.DerDensityByTemperature.
| Name | Value |
|---|---|
unit | "kg/(m3.K)" |
min | -Modelica.Constants.inf |
max | Modelica.Constants.inf |
start | 0. |
Extends from Real.
| Name | Value |
|---|---|
unit | "K/Pa" |
min | -Modelica.Constants.inf |
max | Modelica.Constants.inf |
start | 0. |
This icon is indicates a record.
Extends from Modelica.Icons.Record (Icon for records).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | psat | Saturation pressure |
Temperature | Tsat | Saturation temperature |
The minimum pressure mostly applies to the liquid state only. The minimum density is also arbitrary, but is reasonable for technical applications to limit iterations in non-linear systems. The limits in enthalpy and entropy are used as safeguards in inverse iterations.
Extends from Modelica.Icons.Record (Icon for records).
| Type | Name | Description |
|---|---|---|
Temperature | TMIN | Minimum temperature |
Temperature | TMAX | Maximum temperature |
Density | DMIN | Minimum density |
Density | DMAX | Maximum density |
AbsolutePressure | PMIN | Minimum pressure |
AbsolutePressure | PMAX | Maximum pressure |
SpecificEnthalpy | HMIN | Minimum enthalpy |
SpecificEnthalpy | HMAX | Maximum enthalpy |
SpecificEntropy | SMIN | Minimum entropy |
SpecificEntropy | SMAX | Maximum entropy |
Extends from Integer.
| Name | Value |
|---|---|
min | 0 |
max | 2 |
start | 0 |
This icon is indicates a record.
Extends from Modelica.Media.Interfaces.Types.IdealGas.FluidConstants (Extended fluid constants).
| Type | Name | Description |
|---|---|---|
String | iupacName | Complete IUPAC name (or common name, if non-existent) |
String | casRegistryNumber | Chemical abstracts sequencing number (if it exists) |
String | chemicalFormula | Chemical formula, (brutto, nomenclature according to Hill |
String | structureFormula | Chemical structure formula |
MolarMass | molarMass | Molar mass |
Temperature | criticalTemperature | Critical temperature |
AbsolutePressure | criticalPressure | Critical pressure |
MolarVolume | criticalMolarVolume | Critical molar Volume |
Real | acentricFactor | Pitzer acentric factor |
Temperature | meltingPoint | Melting point at 101325 Pa |
Temperature | normalBoilingPoint | Normal boiling point (at 101325 Pa) |
DipoleMoment | dipoleMoment | Dipole moment of molecule in Debye (1 debye = 3.33564e10-30 C.m) |
Boolean | hasIdealGasHeatCapacity | True if ideal gas heat capacity is available |
Boolean | hasCriticalData | True if critical data are known |
Boolean | hasDipoleMoment | True if a dipole moment known |
Boolean | hasFundamentalEquation | True if a fundamental equation |
Boolean | hasLiquidHeatCapacity | True if liquid heat capacity is available |
Boolean | hasSolidHeatCapacity | True if solid heat capacity is available |
Boolean | hasAccurateViscosityData | True if accurate data for a viscosity function is available |
Boolean | hasAccurateConductivityData | True if accurate data for thermal conductivity is available |
Boolean | hasVapourPressureCurve | True if vapour pressure data, e.g., Antoine coefficients are known |
Boolean | hasAcentricFactor | True if Pitzer acentric factor is known |
SpecificEnthalpy | HCRIT0 | Critical specific enthalpy of the fundamental equation |
SpecificEntropy | SCRIT0 | Critical specific entropy of the fundamental equation |
SpecificEnthalpy | deltah | Difference between specific enthalpy model (h_m) and f.eq. (h_f) (h_m - h_f) |
SpecificEntropy | deltas | Difference between specific enthalpy model (s_m) and f.eq. (s_f) (s_m - s_f) |
This icon is indicates a record.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.ThermodynamicState (Thermodynamic state variables).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Absolute pressure of medium |
Temperature | T | Temperature of medium |
MassFraction | X[nX] | Mass fractions (= (component mass)/total mass m_i/m) |
This model computes thermodynamic properties of moist air from three independent (thermodynamic or/and numerical) state variables. Preferred numerical states are temperature T, pressure p and the reduced composition vector Xi, which contains the water mass fraction only. As an EOS the ideal gas law is used and associated restrictions apply. The model can also be used in the fog region, when moisture is present in its liquid state. However, it is assumed that the liquid water volume is negligible compared to that of the gas phase. Computation of thermal properties is based on property data of dry air and water (source: VDI-Wärmeatlas), respectively. Besides the standard thermodynamic variables absolute and relative humidity, x_water and phi, respectively, are given by the model. Upper case X denotes absolute humidity with respect to mass of moist air while absolute humidity with respect to mass of dry air only is denoted by a lower case x throughout the model. See package description for further information.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.BaseProperties (Base properties (p, d, T, h, u, R, MM and, if applicable, X and Xi) of a medium).
| Type | Name | Default | Description |
|---|---|---|---|
Boolean | preferredMediumStates | false | = true if StateSelect.prefer shall be used for the independent property variables of the medium |
final Boolean | standardOrderComponents | true | If true, and reducedX = true, the last element of X will be computed from the other ones |
| Type | Name | Description |
|---|---|---|
input InputAbsolutePressure | p | Absolute pressure of medium |
input InputMassFraction | Xi[nXi] | Structurally independent mass fractions |
input InputSpecificEnthalpy | h | Specific enthalpy of medium |
The thermodynamic state record is computed from pressure p, temperature T and composition X.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
Temperature | T | Temperature |
MassFraction | X[:] | Mass fractions |
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state |
The thermodynamic state record is computed from pressure p, specific enthalpy h and composition X.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
SpecificEnthalpy | h | Specific enthalpy |
MassFraction | X[:] | Mass fractions |
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state |
The thermodynamic state record is computed from pressure p, specific enthalpy h and composition X.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.setState_psX (Return thermodynamic state as function of p, s and composition X or Xi).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
SpecificEntropy | s | Specific entropy |
MassFraction | X[:] | Mass fractions |
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
The thermodynamic state record is computed from density d, temperature T and composition X.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Density | d | Density |
Temperature | T | Temperature |
MassFraction | X[:] | Mass fractions |
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state |
This function is used to approximate the equation
state = if x > 0 then state_a else state_b;
by a smooth characteristic, so that the expression is continuous and differentiable:
state := smooth(1, if x > x_small then state_a else
if x < -x_small then state_b else f(state_a, state_b));
This is performed by applying function Media.Common.smoothStep(..) on every element of the thermodynamic state record.
If mass fractions X[:] are approximated with this function then this can be performed for all nX mass fractions, instead of applying it for nX-1 mass fractions and computing the last one by the mass fraction constraint sum(X)=1. The reason is that the approximating function has the property that sum(state.X) = 1, provided sum(state_a.X) = sum(state_b.X) = 1. This can be shown by evaluating the approximating function in the abs(x) < x_small region (otherwise state.X is either state_a.X or state_b.X):
X[1] = smoothStep(x, X_a[1] , X_b[1] , x_small);
X[2] = smoothStep(x, X_a[2] , X_b[2] , x_small);
...
X[nX] = smoothStep(x, X_a[nX], X_b[nX], x_small);
or
X[1] = c*(X_a[1] - X_b[1]) + (X_a[1] + X_b[1])/2
X[2] = c*(X_a[2] - X_b[2]) + (X_a[2] + X_b[2])/2;
...
X[nX] = c*(X_a[nX] - X_b[nX]) + (X_a[nX] + X_b[nX])/2;
c = (x/x_small)*((x/x_small)^2 - 3)/4
Summing all mass fractions together results in
sum(X) = c*(sum(X_a) - sum(X_b)) + (sum(X_a) + sum(X_b))/2
= c*(1 - 1) + (1 + 1)/2
= 1
Extends from Modelica.Media.Interfaces.PartialCondensingGases.setSmoothState (Return thermodynamic state so that it smoothly approximates: if x > 0 then state_a else state_b).
| Type | Name | Description |
|---|---|---|
Real | x | m_flow or dp |
ThermodynamicState | state_a | Thermodynamic state if x > 0 |
ThermodynamicState | state_b | Thermodynamic state if x < 0 |
Real | x_small | Smooth transition in the region -x_small < x < x_small |
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Smooth thermodynamic state for all x (continuous and differentiable) |
Dynamic viscosity is computed from temperature using a simple polynomial for dry air. Range of validity is from 123.15 K to 1273.15 K. The influence of pressure and moisture is neglected.
Source: VDI Waermeatlas, 8th edition.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.dynamicViscosity (Return dynamic viscosity).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
DynamicViscosity | eta | Dynamic viscosity |
Thermal conductivity is computed from temperature using a simple polynomial for dry air. Range of validity is from 123.15 K to 1273.15 K. The influence of pressure and moisture is neglected.
Source: VDI Waermeatlas, 8th edition.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.thermalConductivity (Return thermal conductivity).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
ThermalConductivity | lambda | Thermal conductivity |
This icon indicates Modelica functions.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
PrandtlNumber | Pr | Prandtl number |
Pressure is returned from the thermodynamic state record input as a simple assignment.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.pressure (Return pressure).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
Temperature is returned from the thermodynamic state record input as a simple assignment.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.temperature (Return temperature).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
Temperature | T | Temperature |
Density is computed from pressure, temperature and composition in the thermodynamic state record applying the ideal gas law.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.density (Return density).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
Density | d | Density |
Specific enthalpy of moist air is computed from the thermodynamic state record. The fog region is included for both, ice and liquid fog.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.specificEnthalpy (Return specific enthalpy).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
SpecificEnthalpy | h | Specific enthalpy |
Specific internal energy is determined from the thermodynamic state record, assuming that the liquid or solid water volume is negligible.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.specificInternalEnergy (Return specific internal energy) and Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
SpecificEnergy | u | Specific internal energy |
Specific entropy is calculated from the thermodynamic state record, assuming ideal gas behavior and including entropy of mixing. Liquid or solid water is not taken into account, the entire water content X[1] is assumed to be in the vapor state (relative humidity below 1.0).
Extends from Modelica.Media.Interfaces.PartialCondensingGases.specificEntropy (Return specific entropy).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
SpecificEntropy | s | Specific entropy |
The Gibbs Energy is computed from the thermodynamic state record for moist air with a water content below saturation.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.specificGibbsEnergy (Return specific Gibbs energy) and Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
SpecificEnergy | g | Specific Gibbs energy |
The Specific Helmholtz Energy is computed from the thermodynamic state record for moist air with a water content below saturation.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.specificHelmholtzEnergy (Return specific Helmholtz energy) and Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
SpecificEnergy | f | Specific Helmholtz energy |
The specific heat capacity at constant pressure cp is computed from temperature and composition for a mixture of steam (X[1]) and dry air. All water is assumed to be in the vapor state.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.specificHeatCapacityCp (Return specific heat capacity at constant pressure).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
SpecificHeatCapacity | cp | Specific heat capacity at constant pressure |
The specific heat capacity at constant pressure cp is computed from temperature and composition for a mixture of steam (X[1]) and dry air. All water is assumed to be in the vapor state.
Extends from Modelica.Media.Air.MoistAir.specificHeatCapacityCp (Return specific heat capacity at constant pressure as a function of the thermodynamic state record).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
SpecificHeatCapacity | cp | Specific heat capacity at constant pressure |
The specific heat capacity at constant density cv is computed from temperature and composition for a mixture of steam (X[1]) and dry air. All water is assumed to be in the vapor state.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.specificHeatCapacityCv (Return specific heat capacity at constant volume).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
SpecificHeatCapacity | cv | Specific heat capacity at constant volume |
The specific heat capacity at constant density cv is computed from temperature and composition for a mixture of steam (X[1]) and dry air. All water is assumed to be in the vapor state.
Extends from Modelica.Media.Air.MoistAir.specificHeatCapacityCv (Return specific heat capacity at constant volume as a function of the thermodynamic state record).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
SpecificHeatCapacity | cv | Specific heat capacity at constant volume |
This icon indicates Modelica functions.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.isentropicExponent (Return isentropic exponent).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
IsentropicExponent | gamma | Isentropic exponent |
This icon indicates Modelica functions.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.isentropicEnthalpy (Return isentropic enthalpy) and Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p_downstream | Downstream pressure |
ThermodynamicState | refState | Reference state for entropy |
| Type | Name | Description |
|---|---|---|
SpecificEnthalpy | h_is | Isentropic enthalpy |
This icon indicates Modelica functions.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.velocityOfSound (Return velocity of sound).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
VelocityOfSound | a | Velocity of sound |
beta is defined as 1/v * der(v,T), with v = 1/d, at constant pressure p.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.isobaricExpansionCoefficient (Return overall the isobaric expansion coefficient beta).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
IsobaricExpansionCoefficient | beta | Isobaric expansion coefficient |
beta is defined as 1/v * der(v,T), with v = 1/d, at constant pressure p.
Extends from Modelica.Media.Air.MoistAir.isobaricExpansionCoefficient.
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
IsobaricExpansionCoefficient | beta | Isobaric expansion coefficient |
kappa is defined as - 1/v * der(v,p), with v = 1/d at constant temperature T.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.isothermalCompressibility (Return overall the isothermal compressibility factor).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
IsothermalCompressibility | kappa | Isothermal compressibility |
kappa is defined as - 1/v * der(v,p), with v = 1/d at constant temperature T.
Extends from Modelica.Media.Air.MoistAir.isothermalCompressibility.
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
IsothermalCompressibility | kappa | Isothermal compressibility |
This icon indicates Modelica functions.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.density_derp_h (Return density derivative w.r.t. pressure at const specific enthalpy).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
DerDensityByPressure | ddph | Density derivative w.r.t. pressure |
This icon indicates Modelica functions.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.density_derh_p (Return density derivative w.r.t. specific enthalpy at constant pressure).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
DerDensityByEnthalpy | ddhp | Density derivative w.r.t. specific enthalpy |
This icon indicates Modelica functions.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.density_derp_T (Return density derivative w.r.t. pressure at const temperature).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
DerDensityByPressure | ddpT | Density derivative w.r.t. pressure |
This icon indicates Modelica functions.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.density_derT_p (Return density derivative w.r.t. temperature at constant pressure).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
DerDensityByTemperature | ddTp | Density derivative w.r.t. temperature |
This icon indicates Modelica functions.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.density_derX (Return density derivative w.r.t. mass fraction).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
Density | dddX[nX] | Derivative of density w.r.t. mass fraction |
This icon indicates Modelica functions.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.molarMass (Return the molar mass of the medium).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
MolarMass | MM | Mixture molar mass |
This icon indicates Modelica functions.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
Temperature | T | Temperature |
MassFraction | X[:] | Mass fractions |
| Type | Name | Description |
|---|---|---|
SpecificEnthalpy | h | Specific enthalpy |
This icon indicates Modelica functions.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
Temperature | T | Temperature |
MassFraction | X[:] | Mass fractions |
| Type | Name | Description |
|---|---|---|
SpecificEntropy | s | Specific entropy |
This icon indicates Modelica functions.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
Temperature | T | Temperature |
MassFraction | X[:] | Mass fractions |
| Type | Name | Description |
|---|---|---|
Density | d | Density |
This icon indicates Modelica functions.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
SpecificEnthalpy | h | Specific enthalpy |
MassFraction | X[:] | Mass fractions |
| Type | Name | Description |
|---|---|---|
Temperature | T | Temperature |
This icon indicates Modelica functions.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
SpecificEnthalpy | h | Specific enthalpy |
MassFraction | X[:] | Mass fractions |
| Type | Name | Description |
|---|---|---|
Density | d | Density |
This icon indicates Modelica functions.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
SpecificEntropy | s | Specific entropy |
MassFraction | X[:] | Mass fractions |
| Type | Name | Description |
|---|---|---|
Temperature | T | Temperature |
This icon indicates Modelica functions.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
SpecificEntropy | s | Specific entropy |
MassFraction | X[:] | Mass fractions |
| Type | Name | Description |
|---|---|---|
Density | d | Density |
This icon indicates Modelica functions.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
SpecificEntropy | s | Specific entropy |
MassFraction | X[:] | Mass fractions |
| Type | Name | Description |
|---|---|---|
SpecificEnthalpy | h | Specific enthalpy |
Extends from Modelica.SIunits.MassFlowRate.
| Name | Value |
|---|---|
quantity | "MassFlowRate." + mediumName |
unit | "kg/s" |
min | -100000 |
max | 100000 |
start | 0. |
The ideal gas constant for moist air is computed from thermodynamic state assuming that all water is in the gas phase.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.gasConstant (Return the gas constant of the mixture (also for liquids)).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state |
| Type | Name | Description |
|---|---|---|
SpecificHeatCapacity | R | Mixture gas constant |
This icon indicates Modelica functions.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
MoleFraction | moleFractions[:] | Mole fractions of mixture |
MolarMass | MMX[:] | Molar masses of components |
| Type | Name | Description |
|---|---|---|
MassFraction | X[size(moleFractions, 1)] | Mass fractions of gas mixture |
This icon indicates Modelica functions.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
MassFraction | X[:] | Mass fractions of mixture |
MolarMass | MMX[:] | Molar masses of components |
| Type | Name | Description |
|---|---|---|
MoleFraction | moleFractions[size(X, 1)] | Mole fractions of gas mixture |
Saturation pressure of water in the liquid and the solid region is computed using correlations. Functions for the solid and the liquid region, respectively, are combined using the first derivative continuous spliceFunction. This functions range of validity is from 190 to 647.096 K. For more information on the type of correlation used, see the documentation of the linked functions.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.saturationPressure (Return saturation pressure of condensing fluid).
| Type | Name | Description |
|---|---|---|
Temperature | Tsat | Saturation temperature |
| Type | Name | Description |
|---|---|---|
AbsolutePressure | psat | Saturation pressure |
Enthalpy of vaporization of water is computed from temperature in the region of 273.16 to 647.096 K.
Source: W Wagner, A Pruss: "International equations for the saturation properties of ordinary water substance. Revised according to the international temperature scale of 1990" (1993).
Extends from Modelica.Media.Interfaces.PartialCondensingGases.enthalpyOfVaporization (Return vaporization enthalpy of condensing fluid).
| Type | Name | Description |
|---|---|---|
Temperature | T | Temperature |
| Type | Name | Description |
|---|---|---|
SpecificEnthalpy | r0 | Vaporization enthalpy |
Specific enthalpy of liquid water is computed from temperature using a polynomial approach. Kept for compatibility reasons, better use enthalpyOfWater instead.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.enthalpyOfLiquid (Return liquid enthalpy of condensing fluid).
| Type | Name | Description |
|---|---|---|
Temperature | T | Temperature |
| Type | Name | Description |
|---|---|---|
SpecificEnthalpy | h | Liquid enthalpy |
Specific enthalpy of moist air is computed from temperature, provided all water is in the gaseous state. The first entry in the composition vector X must be the mass fraction of steam. For a function that also covers the fog region please refer to h_pTX.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.enthalpyOfGas (Return enthalpy of non-condensing gas mixture).
| Type | Name | Description |
|---|---|---|
Temperature | T | Temperature |
MassFraction | X[:] | Vector of mass fractions |
| Type | Name | Description |
|---|---|---|
SpecificEnthalpy | h | Specific enthalpy |
Specific enthalpy of steam is computed from temperature.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.enthalpyOfCondensingGas (Return enthalpy of condensing gas (most often steam)).
| Type | Name | Description |
|---|---|---|
Temperature | T | Temperature |
| Type | Name | Description |
|---|---|---|
SpecificEnthalpy | h | Specific enthalpy |
Specific enthalpy of dry air is computed from temperature.
Extends from Modelica.Media.Interfaces.PartialCondensingGases.enthalpyOfNonCondensingGas (Return enthalpy of the non-condensing species).
| Type | Name | Description |
|---|---|---|
Temperature | T | Temperature |
| Type | Name | Description |
|---|---|---|
SpecificEnthalpy | h | Specific enthalpy |
Absolute humidity per unit mass of moist air at saturation is computed from pressure and temperature in the state record. Note, that unlike X_sat in the BaseProperties model this mass fraction refers to mass of moist air at saturation.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
MassFraction | X_sat | Steam mass fraction of sat. boundary |
Absolute humidity per unit mass of dry air at saturation is computed from pressure and temperature in the thermodynamic state record.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
| Type | Name | Description |
|---|---|---|
MassFraction | x_sat | Absolute humidity per unit mass of dry air |
Absolute humidity per unit mass of dry air at saturation is computed from pressure and temperature.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
Temperature | T | Temperature |
| Type | Name | Description |
|---|---|---|
MassFraction | x_sat | Absolute humidity per unit mass of dry air |
Absolute humidity per unit mass of moist air is computed from temperature, pressure and relative humidity.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
Temperature | T | Temperature |
Real | phi | Relative humidity (0 ... 1.0) |
| Type | Name | Description |
|---|---|---|
MassFraction | X_steam | Absolute humidity, steam mass fraction |
Relative humidity is computed from pressure, temperature and composition with 1.0 as the upper limit at saturation. Water mass fraction is the first entry in the composition vector.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Pressure | p | Pressure |
Temperature | T | Temperature |
MassFraction | X[:] | Composition |
| Type | Name | Description |
|---|---|---|
Real | phi | Relative humidity |
Relative humidity is computed from the thermodynamic state record with 1.0 as the upper limit at saturation.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
ThermodynamicState | state | Thermodynamic state |
| Type | Name | Description |
|---|---|---|
Real | phi | Relative humidity |
The ideal gas constant for moist air is computed from the gas phase composition. The first entry in composition vector X is the steam mass fraction of the gas phase.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
MassFraction | X[:] | Gas phase composition |
| Type | Name | Description |
|---|---|---|
SpecificHeatCapacity | R | Ideal gas constant |
Saturation pressure of water above the triple point temperature is computed from temperature.
Source: A Saul, W Wagner: "International equations for the saturation properties of ordinary water substance", equation 2.1
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Temperature | Tsat | Saturation temperature |
| Type | Name | Description |
|---|---|---|
AbsolutePressure | psat | Saturation pressure |
Saturation pressure of water above the triple point temperature is computed from temperature.
Source: A Saul, W Wagner: "International equations for the saturation properties of ordinary water substance", equation 2.1
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Temperature | Tsat | Saturation temperature |
Real | dTsat | Saturation temperature derivative |
| Type | Name | Description |
|---|---|---|
Real | psat_der | Saturation pressure derivative |
Sublimation pressure of water below the triple point temperature is computed from temperature.
Source: W Wagner, A Saul, A Pruss: "International equations for the pressure along the melting and along the sublimation curve of ordinary water substance", equation 3.5
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Temperature | Tsat | Sublimation temperature |
| Type | Name | Description |
|---|---|---|
AbsolutePressure | psat | Sublimation pressure |
Sublimation pressure of water below the triple point temperature is computed from temperature.
Source: W Wagner, A Saul, A Pruss: "International equations for the pressure along the melting and along the sublimation curve of ordinary water substance", equation 3.5
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Temperature | Tsat | Sublimation temperature |
Real | dTsat | Sublimation temperature derivative |
| Type | Name | Description |
|---|---|---|
Real | psat_der | Sublimation pressure derivative |
Derivative function of saturationPressure
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Temperature | Tsat | Saturation temperature |
Real | dTsat | Time derivative of saturation temperature |
| Type | Name | Description |
|---|---|---|
Real | psat_der | Saturation pressure |
Computes saturation temperature from (partial) pressure via numerical inversion of the function saturationPressure. Therefore additional inputs are required (or the defaults are used) for upper and lower temperature bounds.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Pressure | p | Pressure |
Temperature | T_min | Lower boundary of solution |
Temperature | T_max | Upper boundary of solution |
| Type | Name | Description |
|---|---|---|
Temperature | T | Saturation temperature |
The specific heat capacity of water (liquid and solid) is calculated using a polynomial approach and data from VDI-Waermeatlas 8. Edition (Db1)
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Temperature | T | Temperature |
| Type | Name | Description |
|---|---|---|
SpecificHeatCapacity | cp_fl | Specific heat capacity of liquid |
Specific enthalpy of water (liquid and solid) is computed from temperature using constant properties as follows:
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Temperature | T | Temperature |
| Type | Name | Description |
|---|---|---|
SpecificEnthalpy | h | Specific enthalpy of water |
Derivative function for enthalpyOfWater.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Temperature | T | Temperature |
Real | dT | Time derivative of temperature |
| Type | Name | Description |
|---|---|---|
Real | dh | Time derivative of specific enthalpy |
Temperature is computed from pressure, specific enthalpy and composition via numerical inversion of function h_pTX.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
SpecificEnthalpy | h | Specific enthalpy |
MassFraction | X[:] | Mass fractions of composition |
| Type | Name | Description |
|---|---|---|
Temperature | T | Temperature |
Specific enthalpy of moist air is computed from pressure, temperature and composition with X[1] as the total water mass fraction. The fog region is included for both, ice and liquid fog.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Pressure | p | Pressure |
Temperature | T | Temperature |
MassFraction | X[:] | Mass fractions of moist air |
| Type | Name | Description |
|---|---|---|
SpecificEnthalpy | h | Specific enthalpy at p, T, X |
Derivative function for h_pTX.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Pressure | p | Pressure |
Temperature | T | Temperature |
MassFraction | X[:] | Mass fractions of moist air |
Real | dp | Pressure derivative |
Real | dT | Temperature derivative |
Real | dX[:] | Composition derivative |
| Type | Name | Description |
|---|---|---|
Real | h_der | Time derivative of specific enthalpy |
This icon indicates Modelica functions.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p2 | Downstream pressure |
ThermodynamicState | state | Thermodynamic state at upstream location |
| Type | Name | Description |
|---|---|---|
SpecificEnthalpy | h_is | Isentropic enthalpy |
Specific internal energy is determined from pressure p, temperature T and composition X, assuming that the liquid or solid water volume is negligible.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Pressure | p | Pressure |
Temperature | T | Temperature |
MassFraction | X[:] | Mass fractions of moist air |
| Type | Name | Description |
|---|---|---|
SpecificInternalEnergy | u | Specific internal energy |
Derivative function for specificInternalEnergy_pTX.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Pressure | p | Pressure |
Temperature | T | Temperature |
MassFraction | X[:] | Mass fractions of moist air |
Real | dp | Pressure derivative |
Real | dT | Temperature derivative |
Real | dX[:] | Mass fraction derivatives |
| Type | Name | Description |
|---|---|---|
Real | u_der | Specific internal energy derivative |
Temperature is computed from pressure, specific entropy and composition via numerical inversion of function specificEntropy.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
AbsolutePressure | p | Pressure |
SpecificEntropy | s | Specific entropy |
MassFraction | X[:] | Mass fractions of composition |
| Type | Name | Description |
|---|---|---|
Temperature | T | Temperature |
Specific entropy of moist air is computed from pressure, temperature and composition with X[1] as the total water mass fraction.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Pressure | p | Pressure |
Temperature | T | Temperature |
MassFraction | X[:] | Mass fractions of moist air |
| Type | Name | Description |
|---|---|---|
SpecificEntropy | s | Specific entropy at p, T, X |
Specific entropy of moist air is computed from pressure, temperature and composition with X[1] as the total water mass fraction.
Extends from Modelica.Icons.Function (Icon for functions).
| Type | Name | Description |
|---|---|---|
Pressure | p | Pressure |
Temperature | T | Temperature |
MassFraction | X[:] | Mass fractions of moist air |
Real | dp | Derivative of pressure |
Real | dT | Derivative of temperature |
Real | dX[nX] | Derivative of mass fractions |
| Type | Name | Description |
|---|---|---|
Real | ds | Specific entropy at p, T, X |
Generated 2018-12-12 12:13:50 EST by MapleSim.