This is a medium model that is similar to Modelica.Media.Air.MoistAir but it is a perfect gas, i.e., it has a constant specific heat capacity.
Extends from Modelica.Media.Interfaces.PartialCondensingGases (Base class for mixtures of condensing and non-condensing gases).
Name | Description |
---|---|
Water=1 | Index of water (in substanceNames, massFractions X, etc.) |
Air=2 | Index of air (in substanceNames, massFractions X, etc.) |
k_mair=steam.MM/dryair.MM | Ratio of molar weights |
dryair=Buildings.Media.PerfectGases.Common.SingleGasData.Air | |
steam=Buildings.Media.PerfectGases.Common.SingleGasData.H2O | |
TMin=200 | Minimum temperature |
TMax=400 | Maximum temperature |
![]() | ThermodynamicState record for moist air |
![]() | |
![]() | Steam water mass fraction of saturation boundary in kg_water/kg_moistair |
![]() | Thermodynamic state as function of p, T and composition X |
![]() | Thermodynamic state as function of p, h and composition X |
![]() | Thermodynamic state as function of d, T and composition X |
![]() | Gas constant (computation neglects liquid fraction) |
![]() | Return saturation pressure of water as a function of temperature T in the range of 273.16 to 373.16 K |
![]() | Time derivative of saturationPressureLiquid |
![]() | Saturation curve valid for 223.16 <= T <= 273.16. Outside of these limits a (less accurate) result is returned |
![]() | Saturation curve valid for 223.16 <= T <= 373.16 (and slightly outside with less accuracy) |
![]() | Gas pressure |
![]() | Gas temperature |
![]() | Gas density |
![]() | Specific entropy (liquid part neglected, mixing entropy included) |
![]() | Enthalpy of vaporization of water |
![]() | Specific heat capacity of water (liquid only) which is constant |
![]() | Enthalpy of liquid (per unit mass of liquid) which is linear in the temperature |
![]() | Temperature derivative of enthalpy of liquid per unit mass of liquid |
![]() | Enthalpy of steam per unit mass of steam |
![]() | Derivative of enthalpy of steam per unit mass of steam |
![]() | Enthalpy of non-condensing gas per unit mass of steam |
![]() | Derivative of enthalpy of non-condensing gas per unit mass of steam |
![]() | Enthalpy of gas mixture per unit mass of gas mixture |
![]() | Enthalpy of dry air per unit mass of dry air |
![]() | Derivative of enthalpy of dry air per unit mass of dry air |
![]() | Specific heat capacity of gas mixture at constant pressure |
![]() | Specific heat capacity of gas mixture at constant volume |
![]() | dynamic viscosity of dry air |
![]() | Thermal conductivity of dry air as a polynomial in the temperature |
![]() | Compute specific enthalpy from pressure, temperature and mass fraction |
![]() | Specific enthalpy |
![]() | Specific internal energy |
![]() | Specific Gibbs energy |
![]() | Specific Helmholtz energy |
![]() | Compute temperature from specific enthalpy and mass fraction |
Inherited | |
![]() | extended fluid constants |
fluidConstants | constant data for the fluid |
![]() | Return mass fractions X from mole fractions |
![]() | Return mole fractions from mass fractions X |
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 |
![]() | Return thermodynamic state as function of p, s and composition X or Xi |
![]() | Return thermodynamic state so that it smoothly approximates: if x > 0 then state_a else state_b |
![]() | Return the Prandtl number |
![]() | alias for deprecated name |
![]() | alias for deprecated name |
![]() | Return isentropic exponent |
![]() | Return isentropic enthalpy |
![]() | Return velocity of sound |
![]() | Return overall the isobaric expansion coefficient beta |
![]() | alias for isobaricExpansionCoefficient for user convenience |
![]() | Return overall the isothermal compressibility factor |
![]() | alias of isothermalCompressibility for user convenience |
![]() | Return density derivative w.r.t. pressure at const specific enthalpy |
![]() | Return density derivative w.r.t. specific enthalpy at constant pressure |
![]() | Return density derivative w.r.t. pressure at const temperature |
![]() | Return density derivative w.r.t. temperature at constant pressure |
![]() | Return density derivative w.r.t. mass fraction |
![]() | Return the molar mass of the medium |
![]() | Return specific enthalpy from p, T, and X or Xi |
![]() | Return specific enthalpy from p, T, and X or Xi |
![]() | Return density from p, T, and X or Xi |
![]() | Return temperature from p, h, and X or Xi |
![]() | Return density from p, h, and X or Xi |
![]() | Return temperature from p,s, and X or Xi |
![]() | Return density from p, s, and X or Xi |
![]() | Return specific enthalpy from p, s, and X or Xi |
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 |
MassFlowRate | Type for mass 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 resect to pressure with medium specific attributes |
DerDensityByEnthalpy | Type for partial derivative of density with resect to enthalpy with medium specific attributes |
DerEnthalpyByPressure | Type for partial derivative of enthalpy with resect to pressure with medium specific attributes |
DerDensityByTemperature | Type for partial derivative of density with resect to temperature with medium specific attributes |
![]() | Types, constants to define menu choices |
constant Integer Water=1 "Index of water (in substanceNames, massFractions X, etc.)";
constant Integer Air=2 "Index of air (in substanceNames, massFractions X, etc.)";
constant Real k_mair = steam.MM/dryair.MM "Ratio of molar weights";
constant Buildings.Media.PerfectGases.Common.DataRecord dryair= Buildings.Media.PerfectGases.Common.SingleGasData.Air;
constant Buildings.Media.PerfectGases.Common.DataRecord steam= Buildings.Media.PerfectGases.Common.SingleGasData.H2O;
constant Modelica.SIunits.Temperature TMin = 200 "Minimum temperature";
constant Modelica.SIunits.Temperature TMax = 400 "Maximum temperature";
redeclare record extends ThermodynamicState "ThermodynamicState record for moist air" end ThermodynamicState;
Type | Name | Default | Description |
---|---|---|---|
Boolean | standardOrderComponents | true | if true, and reducedX = true, the last element of X will be computed from the other ones |
Advanced | |||
Boolean | preferredMediumStates | false | = true if StateSelect.prefer shall be used for the independent property variables of the medium |
redeclare replaceable model extends BaseProperties( T(stateSelect=if preferredMediumStates then StateSelect.prefer else StateSelect.default), p(stateSelect=if preferredMediumStates then StateSelect.prefer else StateSelect.default), Xi(each stateSelect=if preferredMediumStates then StateSelect.prefer else StateSelect.default), final standardOrderComponents=true) /* p, T, X = X[Water] are used as preferred states, since only then all other quantities can be computed in a recursive sequence. If other variables are selected as states, static state selection is no longer possible and non-linear algebraic equations occur. */ MassFraction x_water "Mass of total water/mass of dry air"; Real phi "Relative humidity"; protected constant SI.MolarMass[2] MMX = {steam.MM,dryair.MM} "Molar masses of components"; MassFraction X_liquid "Mass fraction of liquid water"; MassFraction X_steam "Mass fraction of steam water"; MassFraction X_air "Mass fraction of air"; MassFraction X_sat "Steam water mass fraction of saturation boundary in kg_water/kg_moistair"; MassFraction x_sat "Steam water mass content of saturation boundary in kg_water/kg_dryair"; AbsolutePressure p_steam_sat "Partial saturation pressure of steam"; equation assert(T >= TMin and T <= TMax, " Temperature T is not in the allowed range " + String(TMin) + " <= (T =" + String(T) + " K) <= " + String(TMax) + " K required from medium model \"" + mediumName + "\"."); MM = 1/(Xi[Water]/MMX[Water]+(1.0-Xi[Water])/MMX[Air]); p_steam_sat = min(saturationPressure(T),0.999*p); X_sat = min(p_steam_sat * k_mair/max(100*Modelica.Constants.eps, p - p_steam_sat)*(1 - Xi[Water]), 1.0) "Water content at saturation with respect to actual water content"; X_liquid = max(Xi[Water] - X_sat, 0.0); X_steam = Xi[Water]-X_liquid; X_air = 1-Xi[Water]; h = specificEnthalpy_pTX(p,T,Xi); R = dryair.R*(1 - X_steam/(1 - X_liquid)) + steam.R*X_steam/(1 - X_liquid); // u = h - R*T; d = p/(R*T); /* Note, u and d are computed under the assumption that the volume of the liquid water is neglible with respect to the volume of air and of steam */ state.p = p; state.T = T; state.X = X; // this x_steam is water load / dry air!!!!!!!!!!! x_sat = k_mair*p_steam_sat/max(100*Modelica.Constants.eps,p - p_steam_sat); x_water = Xi[Water]/max(X_air,100*Modelica.Constants.eps); phi = p/p_steam_sat*Xi[Water]/(Xi[Water] + k_mair*X_air); end BaseProperties;
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Type | Name | Description |
---|---|---|
MassFraction | X_sat | Steam mass fraction of sat. boundary [kg/kg] |
function Xsaturation = Modelica.Media.Air.MoistAir.Xsaturation "Steam water mass fraction of saturation boundary in kg_water/kg_moistair";
Type | Name | Default | Description |
---|---|---|---|
AbsolutePressure | p | Pressure [Pa] | |
Temperature | T | Temperature [K] | |
MassFraction | X[:] | reference_X | Mass fractions [kg/kg] |
Type | Name | Description |
---|---|---|
ThermodynamicState | state | Thermodynamic state |
redeclare function setState_pTX "Thermodynamic state as function of p, T and composition X" extends Modelica.Media.Air.MoistAir.setState_pTX; end setState_pTX;
T_phX
provided by this package as opposed to the
implementation provided by its parent package.
Extends from Modelica.Icons.Function (Icon for functions).
Type | Name | Default | Description |
---|---|---|---|
AbsolutePressure | p | Pressure [Pa] | |
SpecificEnthalpy | h | Specific enthalpy [J/kg] | |
MassFraction | X[:] | Mass fractions [kg/kg] |
Type | Name | Description |
---|---|---|
ThermodynamicState | state |
redeclare function setState_phX "Thermodynamic state as function of p, h and composition X" extends Modelica.Icons.Function; input AbsolutePressure p "Pressure"; input SpecificEnthalpy h "Specific enthalpy"; input MassFraction X[:] "Mass fractions"; output ThermodynamicState state; algorithm state := if size(X,1) == nX then ThermodynamicState(p=p,T=T_phX(p,h,X),X=X) else ThermodynamicState(p=p,T=T_phX(p,h,X), X=cat(1,X,{1-sum(X)}));end setState_phX;
Type | Name | Default | Description |
---|---|---|---|
Density | d | density [kg/m3] | |
Temperature | T | Temperature [K] | |
MassFraction | X[:] | reference_X | Mass fractions [kg/kg] |
Type | Name | Description |
---|---|---|
ThermodynamicState | state | Thermodynamic state |
redeclare function setState_dTX "Thermodynamic state as function of d, T and composition X" extends Modelica.Media.Air.MoistAir.setState_dTX; end setState_dTX;
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | thermodynamic state |
Type | Name | Description |
---|---|---|
SpecificHeatCapacity | R | mixture gas constant [J/(kg.K)] |
redeclare function gasConstant "Gas constant (computation neglects liquid fraction)" extends Modelica.Media.Air.MoistAir.gasConstant; end gasConstant;
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] |
function saturationPressureLiquid "Return saturation pressure of water as a function of temperature T in the range of 273.16 to 373.16 K" annotation(derivative=saturationPressureLiquid_der); extends Modelica.Icons.Function; input SI.Temperature Tsat "saturation temperature"; output SI.AbsolutePressure psat "saturation pressure"; algorithm psat := 611.657*Modelica.Math.exp(17.2799 - 4102.99/(Tsat - 35.719));end saturationPressureLiquid;
Extends from Modelica.Icons.Function (Icon for functions).
Type | Name | Default | Description |
---|---|---|---|
Temperature | Tsat | Saturation temperature [K] | |
Real | dTsat | Saturation temperature derivative [K/s] |
Type | Name | Description |
---|---|---|
Real | psat_der | Saturation pressure [Pa/s] |
function saturationPressureLiquid_der "Time derivative of saturationPressureLiquid" extends Modelica.Icons.Function; input SI.Temperature Tsat "Saturation temperature"; input Real dTsat(unit="K/s") "Saturation temperature derivative"; output Real psat_der(unit="Pa/s") "Saturation pressure"; algorithm psat_der:=611.657*Modelica.Math.exp(17.2799 - 4102.99/(Tsat - 35.719))*4102.99*dTsat/(Tsat - 35.719)/(Tsat - 35.719);end saturationPressureLiquid_der;
Type | Name | Default | Description |
---|---|---|---|
Temperature | Tsat | sublimation temperature [K] |
Type | Name | Description |
---|---|---|
AbsolutePressure | psat | sublimation pressure [Pa] |
function sublimationPressureIce = Modelica.Media.Air.MoistAir.sublimationPressureIce "Saturation curve valid for 223.16 <= T <= 273.16. Outside of these limits a (less accurate) result is returned";
Type | Name | Default | Description |
---|---|---|---|
Temperature | Tsat | saturation temperature [K] |
Type | Name | Description |
---|---|---|
AbsolutePressure | psat | saturation pressure [Pa] |
redeclare function extends saturationPressure "Saturation curve valid for 223.16 <= T <= 373.16 (and slightly outside with less accuracy)" algorithm psat := Buildings.Utilities.Math.Functions.spliceFunction( saturationPressureLiquid(Tsat),sublimationPressureIce(Tsat),Tsat-273.16,1.0);end saturationPressure;
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | thermodynamic state record |
Type | Name | Description |
---|---|---|
AbsolutePressure | p | Pressure [Pa] |
redeclare function pressure "Gas pressure" extends Modelica.Media.Air.MoistAir.pressure; end pressure;
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | thermodynamic state record |
Type | Name | Description |
---|---|---|
Temperature | T | Temperature [K] |
redeclare function temperature "Gas temperature" extends Modelica.Media.Air.MoistAir.temperature; end temperature;
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | thermodynamic state record |
Type | Name | Description |
---|---|---|
Density | d | Density [kg/m3] |
redeclare function density "Gas density" extends Modelica.Media.Air.MoistAir.density; end density;
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | thermodynamic state record |
Type | Name | Description |
---|---|---|
SpecificEntropy | s | Specific entropy [J/(kg.K)] |
redeclare function specificEntropy "Specific entropy (liquid part neglected, mixing entropy included)" extends Modelica.Media.Air.MoistAir.specificEntropy; end specificEntropy;
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] |
Type | Name | Description |
---|---|---|
SpecificEnthalpy | r0 | vaporization enthalpy [J/kg] |
redeclare function extends enthalpyOfVaporization "Enthalpy of vaporization of water" algorithm r0 := 2501014.5; end enthalpyOfVaporization;
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | [K] |
Type | Name | Description |
---|---|---|
SpecificHeatCapacity | cp_fl | [J/(kg.K)] |
function HeatCapacityOfWater "Specific heat capacity of water (liquid only) which is constant" extends Modelica.Icons.Function; input Temperature T; output SpecificHeatCapacity cp_fl; algorithm cp_fl := 4186; end HeatCapacityOfWater;
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] |
Type | Name | Description |
---|---|---|
SpecificEnthalpy | h | liquid enthalpy [J/kg] |
redeclare replaceable function extends enthalpyOfLiquid "Enthalpy of liquid (per unit mass of liquid) which is linear in the temperature" annotation(derivative=der_enthalpyOfLiquid); algorithm h := (T - 273.15)*4186;end enthalpyOfLiquid;
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] | |
Real | der_T | temperature derivative |
Type | Name | Description |
---|---|---|
Real | der_h | derivative of liquid enthalpy |
replaceable function der_enthalpyOfLiquid "Temperature derivative of enthalpy of liquid per unit mass of liquid" extends Modelica.Icons.Function; input Temperature T "temperature"; input Real der_T "temperature derivative"; output Real der_h "derivative of liquid enthalpy"; algorithm der_h := 4186*der_T; end der_enthalpyOfLiquid;
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] |
Type | Name | Description |
---|---|---|
SpecificEnthalpy | h | steam enthalpy [J/kg] |
redeclare function enthalpyOfCondensingGas "Enthalpy of steam per unit mass of steam" annotation(derivative=der_enthalpyOfCondensingGas); extends Modelica.Icons.Function; input Temperature T "temperature"; output SpecificEnthalpy h "steam enthalpy"; algorithm h := (T-273.15) * steam.cp + enthalpyOfVaporization(T);end enthalpyOfCondensingGas;
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] | |
Real | der_T | temperature derivative |
Type | Name | Description |
---|---|---|
Real | der_h | derivative of steam enthalpy |
replaceable function der_enthalpyOfCondensingGas "Derivative of enthalpy of steam per unit mass of steam" extends Modelica.Icons.Function; input Temperature T "temperature"; input Real der_T "temperature derivative"; output Real der_h "derivative of steam enthalpy"; algorithm der_h := steam.cp*der_T; end der_enthalpyOfCondensingGas;
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] |
Type | Name | Description |
---|---|---|
SpecificEnthalpy | h | enthalpy [J/kg] |
redeclare function enthalpyOfNonCondensingGas "Enthalpy of non-condensing gas per unit mass of steam" annotation(derivative=der_enthalpyOfNonCondensingGas); extends Modelica.Icons.Function; input Temperature T "temperature"; output SpecificEnthalpy h "enthalpy"; algorithm h := enthalpyOfDryAir(T);end enthalpyOfNonCondensingGas;
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] | |
Real | der_T | temperature derivative |
Type | Name | Description |
---|---|---|
Real | der_h | derivative of steam enthalpy |
replaceable function der_enthalpyOfNonCondensingGas "Derivative of enthalpy of non-condensing gas per unit mass of steam" extends Modelica.Icons.Function; input Temperature T "temperature"; input Real der_T "temperature derivative"; output Real der_h "derivative of steam enthalpy"; algorithm der_h := der_enthalpyOfDryAir(T, der_T); end der_enthalpyOfNonCondensingGas;
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] | |
MassFraction | X[:] | vector of mass fractions [kg/kg] |
Type | Name | Description |
---|---|---|
SpecificEnthalpy | h | specific enthalpy [J/kg] |
redeclare replaceable function extends enthalpyOfGas "Enthalpy of gas mixture per unit mass of gas mixture" algorithm h := enthalpyOfCondensingGas(T)*X[Water] + enthalpyOfDryAir(T)*(1.0-X[Water]); end enthalpyOfGas;
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] |
Type | Name | Description |
---|---|---|
SpecificEnthalpy | h | dry air enthalpy [J/kg] |
replaceable function enthalpyOfDryAir "Enthalpy of dry air per unit mass of dry air" annotation(derivative=der_enthalpyOfDryAir); extends Modelica.Icons.Function; input Temperature T "temperature"; output SpecificEnthalpy h "dry air enthalpy"; algorithm h := (T - 273.15)*dryair.cp;end enthalpyOfDryAir;
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] | |
Real | der_T | temperature derivative |
Type | Name | Description |
---|---|---|
Real | der_h | derivative of dry air enthalpy |
replaceable function der_enthalpyOfDryAir "Derivative of enthalpy of dry air per unit mass of dry air" extends Modelica.Icons.Function; input Temperature T "temperature"; input Real der_T "temperature derivative"; output Real der_h "derivative of dry air enthalpy"; algorithm der_h := dryair.cp*der_T; end der_enthalpyOfDryAir;
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | thermodynamic state record |
Type | Name | Description |
---|---|---|
SpecificHeatCapacity | cp | Specific heat capacity at constant pressure [J/(kg.K)] |
redeclare replaceable function extends specificHeatCapacityCp "Specific heat capacity of gas mixture at constant pressure" algorithm cp := dryair.cp*(1-state.X[Water]) +steam.cp*state.X[Water];end specificHeatCapacityCp;
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | thermodynamic state record |
Type | Name | Description |
---|---|---|
SpecificHeatCapacity | cv | Specific heat capacity at constant volume [J/(kg.K)] |
redeclare replaceable function extends specificHeatCapacityCv "Specific heat capacity of gas mixture at constant volume" algorithm cv:= dryair.cv*(1-state.X[Water]) +steam.cv*state.X[Water];end specificHeatCapacityCv;
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | thermodynamic state record |
Type | Name | Description |
---|---|---|
DynamicViscosity | eta | Dynamic viscosity [Pa.s] |
redeclare function extends dynamicViscosity "dynamic viscosity of dry air" algorithm eta := 1.85E-5; end dynamicViscosity;
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | thermodynamic state record |
Type | Name | Description |
---|---|---|
ThermalConductivity | lambda | Thermal conductivity [W/(m.K)] |
redeclare function extends thermalConductivity "Thermal conductivity of dry air as a polynomial in the temperature" algorithm lambda := Modelica.Media.Incompressible.TableBased.Polynomials_Temp.evaluate( {(-4.8737307422969E-008), 7.67803133753502E-005, 0.0241814385504202}, Modelica.SIunits.Conversions.to_degC(state.T)); end thermalConductivity;
Type | Name | Default | Description |
---|---|---|---|
Pressure | p | Pressure [Pa] | |
Temperature | T | Temperature [K] | |
MassFraction | X[:] | Mass fractions of moist air [1] |
Type | Name | Description |
---|---|---|
SpecificEnthalpy | h | Specific enthalpy at p, T, X [J/kg] |
function h_pTX "Compute specific enthalpy from pressure, temperature and mass fraction" extends Modelica.Icons.Function; input SI.Pressure p "Pressure"; input SI.Temperature T "Temperature"; input SI.MassFraction X[:] "Mass fractions of moist air"; output SI.SpecificEnthalpy h "Specific enthalpy at p, T, X"; protected SI.AbsolutePressure p_steam_sat "Partial saturation pressure of steam"; SI.MassFraction x_sat "steam water mass fraction of saturation boundary"; SI.MassFraction X_liquid "mass fraction of liquid water"; SI.MassFraction X_steam "mass fraction of steam water"; SI.MassFraction X_air "mass fraction of air"; SI.SpecificEnthalpy hDryAir "Enthalpy of dry air"; algorithm p_steam_sat :=saturationPressure(T); x_sat :=k_mair*p_steam_sat/(p - p_steam_sat); X_liquid :=max(X[Water] - x_sat/(1 + x_sat), 0.0); X_steam :=X[Water] - X_liquid; X_air :=1 - X[Water]; /* THIS DOES NOT WORK -------------------------- h := enthalpyOfDryAir(T) * X_air + Modelica.Media.Air.MoistAir.enthalpyOfCondensingGas(T) * X_steam + enthalpyOfLiquid(T)*X_liquid; --------------------------------- */ /* THIS WORKS!!!! +++++++++++++++++++++ h := (T - 273.15)*dryair.cp * X_air + Modelica.Media.Air.MoistAir.enthalpyOfCondensingGas(T) * X_steam + enthalpyOfLiquid(T)*X_liquid; +++++++++++++++++++++*/ hDryAir := (T - 273.15)*dryair.cp; h := hDryAir * X_air + ((T-273.15) * steam.cp + 2501014.5) * X_steam + (T - 273.15)*4186*X_liquid;end h_pTX;
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | thermodynamic state record |
Type | Name | Description |
---|---|---|
SpecificEnthalpy | h | Specific enthalpy [J/kg] |
redeclare function extends specificEnthalpy "Specific enthalpy" algorithm h := h_pTX(state.p, state.T, state.X); end specificEnthalpy;
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | thermodynamic state record |
Type | Name | Description |
---|---|---|
SpecificEnergy | u | Specific internal energy [J/kg] |
redeclare function extends specificInternalEnergy "Specific internal energy" extends Modelica.Icons.Function; algorithm u := h_pTX(state.p,state.T,state.X) - gasConstant(state)*state.T; end specificInternalEnergy;
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | thermodynamic state record |
Type | Name | Description |
---|---|---|
SpecificEnergy | g | Specific Gibbs energy [J/kg] |
redeclare function extends specificGibbsEnergy "Specific Gibbs energy" extends Modelica.Icons.Function; algorithm g := h_pTX(state.p,state.T,state.X) - state.T*specificEntropy(state); end specificGibbsEnergy;
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | thermodynamic state record |
Type | Name | Description |
---|---|---|
SpecificEnergy | f | Specific Helmholtz energy [J/kg] |
redeclare function extends specificHelmholtzEnergy "Specific Helmholtz energy" extends Modelica.Icons.Function; algorithm f := h_pTX(state.p,state.T,state.X) - gasConstant(state)*state.T - state.T*specificEntropy(state); end specificHelmholtzEnergy;
Type | Name | Default | Description |
---|---|---|---|
AbsolutePressure | p | Pressure [Pa] | |
SpecificEnthalpy | h | Specific enthalpy [J/kg] | |
MassFraction | X[:] | Mass fractions of composition [kg/kg] |
Type | Name | Description |
---|---|---|
Temperature | T | Temperature [K] |
function T_phX "Compute temperature from specific enthalpy and mass fraction" input AbsolutePressure p "Pressure"; input SpecificEnthalpy h "Specific enthalpy"; input MassFraction X[:] "Mass fractions of composition"; output Temperature T "Temperature"; protectedpackage Internal "Solve h(data,T) for T with given h (use only indirectly via temperature_phX)" extends Modelica.Media.Common.OneNonLinearEquation; redeclare record extends f_nonlinear_Data "Data to be passed to non-linear function" extends Modelica.Media.IdealGases.Common.DataRecord; end f_nonlinear_Data; redeclare function extends f_nonlinear algorithm y := h_pTX(p,x,X); end f_nonlinear; // Dummy definition has to be added for current Dymola redeclare function extends solve end solve; end Internal ; protected constant Modelica.Media.IdealGases.Common.DataRecord steam= Modelica.Media.IdealGases.Common.SingleGasesData.H2O; protected SI.AbsolutePressure p_steam_sat "Partial saturation pressure of steam"; SI.MassFraction x_sat "steam water mass fraction of saturation boundary"; algorithm T := 273.15 + (h - 2501014.5 * X[Water])/((1 - X[Water])*dryair.cp + X[Water] * Buildings.Media.PerfectGases.Common.SingleGasData.H2O.cp); // check for saturation p_steam_sat :=saturationPressure(T); x_sat :=k_mair*p_steam_sat/(p - p_steam_sat); // If the state is in the fog region, then the above equation is not valid, and // T is computed by inverting h_pTX(), which is much more costly. // For Buildings.Fluid.HeatExchangers.Examples.WetEffectivenessNTUPControl, the // computation above reduces the computing time by about a factor of 2. if (X[Water] > x_sat/(1 + x_sat)) then T := Internal.solve(h, TMin, TMax, p, X[1:nXi], steam); end if;end T_phX;