WOLFRAM SYSTEM MODELER
TableBasedIncompressible medium properties based on tables |
Function to invert temperatures |
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Base properties of T dependent medium |
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Returns state record, given pressure and temperature |
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Returns state record, given pressure and temperature |
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Returns state record as function of p and T |
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Returns state record, given pressure and specific enthalpy |
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Returns state record as function of p and h |
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Returns state record, given pressure and specific entropy |
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Returns state record as function of p and s |
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Return thermodynamic state so that it smoothly approximates: if x > 0 then state_a else state_b |
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Specific heat capacity at constant volume (or pressure) of medium |
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Specific heat capacity at constant volume (or pressure) of medium |
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Return dynamic viscosity as a function of the thermodynamic state record |
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Return thermal conductivity as a function of the thermodynamic state record |
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Compute specific entropy |
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Return specific entropy as a function of the thermodynamic state record |
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Compute specific enthalpy from temperature |
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Compute specific enthalpy from temperature |
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Compute specific enthalpy from pressure and temperature |
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Return density as function of temperature |
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Return temperature as a function of the thermodynamic state record |
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Return pressure as a function of the thermodynamic state record |
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Return density as a function of the thermodynamic state record |
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Return specific enthalpy as a function of the thermodynamic state record |
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Return specific internal energy as a function of the thermodynamic state record |
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Compute temperature from pressure and specific enthalpy |
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Compute temperature from pressure and specific enthalpy |
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specificEnthalpyOfT Protected Return specific enthalpy from pressure and temperature, taking the flag enthalpyOfT into account |
ThermoStates |
Value: if enthalpyOfT then Modelica.Media.Interfaces.Choices.IndependentVariables.T else Modelica.Media.Interfaces.Choices.IndependentVariables.pT Type: IndependentVariables Description: Enumeration type for independent variables |
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mediumName |
Value: "tableMedium" Type: String Description: Name of the medium |
substanceNames |
Value: {mediumName} Type: String[:] Description: Names of the mixture substances. Set substanceNames={mediumName} if only one substance. |
extraPropertiesNames |
Value: fill("", 0) Type: String[:] Description: Names of the additional (extra) transported properties. Set extraPropertiesNames=fill("",0) if unused |
singleState |
Value: true Type: Boolean Description: = true, if u and d are not a function of pressure |
reducedX |
Value: true Type: Boolean Description: = true if medium contains the equation sum(X) = 1.0; set reducedX=true if only one substance (see docu for details) |
fixedX |
Value: true Type: Boolean Description: = true if medium contains the equation X = reference_X |
reference_p |
Value: 1.013e5 Type: AbsolutePressure (Pa) Description: Reference pressure of Medium: default 1 atmosphere |
reference_T |
Value: 298.15 Type: Temperature (K) Description: Reference temperature of Medium: default 25 deg Celsius |
reference_X |
Value: fill(1 / nX, nX) Type: MassFraction[nX] (kg/kg) Description: Default mass fractions of medium |
p_default |
Value: 101325 Type: AbsolutePressure (Pa) Description: Default value for pressure of medium (for initialization) |
T_default |
Value: Modelica.Units.Conversions.from_degC(20) Type: Temperature (K) Description: Default value for temperature of medium (for initialization) |
h_default |
Value: specificEnthalpy_pTX(p_default, T_default, X_default) Type: SpecificEnthalpy (J/kg) Description: Default value for specific enthalpy of medium (for initialization) |
X_default |
Value: reference_X Type: MassFraction[nX] (kg/kg) Description: Default value for mass fractions of medium (for initialization) |
C_default |
Value: fill(0, nC) Type: ExtraProperty[nC] Description: Default value for trace substances of medium (for initialization) |
nS |
Value: size(substanceNames, 1) Type: Integer Description: Number of substances |
nX |
Value: nS Type: Integer Description: Number of mass fractions |
nXi |
Value: if fixedX then 0 else if reducedX then nS - 1 else nS Type: Integer Description: Number of structurally independent mass fractions (see docu for details) |
nC |
Value: size(extraPropertiesNames, 1) Type: Integer Description: Number of extra (outside of standard mass-balance) transported properties |
C_nominal |
Value: 1.0e-6 * ones(nC) Type: Real[nC] Description: Default for the nominal values for the extra properties |
enthalpyOfT |
Value: true Type: Boolean Description: True if enthalpy is approximated as a function of T only, (p-dependence neglected) |
densityOfT |
Value: size(tableDensity, 1) > 1 Type: Boolean Description: True if density is a function of temperature |
T_min |
Value: Type: Temperature (K) Description: Minimum temperature valid for medium model |
T_max |
Value: Type: Temperature (K) Description: Maximum temperature valid for medium model |
T0 |
Value: 273.15 Type: Temperature (K) Description: Reference Temperature |
h0 |
Value: 0 Type: SpecificEnthalpy (J/kg) Description: Reference enthalpy at T0, reference_p |
s0 |
Value: 0 Type: SpecificEntropy (J/(kg⋅K)) Description: Reference entropy at T0, reference_p |
MM_const |
Value: 0.1 Type: MolarMass (kg/mol) Description: Molar mass |
npol |
Value: 2 Type: Integer Description: Degree of polynomial used for fitting |
npolDensity |
Value: npol Type: Integer Description: Degree of polynomial used for fitting rho(T) |
npolHeatCapacity |
Value: npol Type: Integer Description: Degree of polynomial used for fitting Cp(T) |
npolViscosity |
Value: npol Type: Integer Description: Degree of polynomial used for fitting eta(T) |
npolVaporPressure |
Value: npol Type: Integer Description: Degree of polynomial used for fitting pVap(T) |
npolConductivity |
Value: npol Type: Integer Description: Degree of polynomial used for fitting lambda(T) |
neta |
Value: size(tableViscosity, 1) Type: Integer Description: Number of data points for viscosity |
tableDensity |
Value: Type: Real[:,2] Description: Table for rho(T) |
tableHeatCapacity |
Value: Type: Real[:,2] Description: Table for Cp(T) |
tableViscosity |
Value: Type: Real[:,2] Description: Table for eta(T) |
tableVaporPressure |
Value: Type: Real[:,2] Description: Table for pVap(T) |
tableConductivity |
Value: Type: Real[:,2] Description: Table for lambda(T) |
TinK |
Value: Type: Boolean Description: True if T[K],Kelvin used for table temperatures |
hasDensity |
Value: not size(tableDensity, 1) == 0 Type: Boolean Description: True if table tableDensity is present |
hasHeatCapacity |
Value: not size(tableHeatCapacity, 1) == 0 Type: Boolean Description: True if table tableHeatCapacity is present |
hasViscosity |
Value: not size(tableViscosity, 1) == 0 Type: Boolean Description: True if table tableViscosity is present |
hasVaporPressure |
Value: not size(tableVaporPressure, 1) == 0 Type: Boolean Description: True if table tableVaporPressure is present |
invTK |
Value: if size(tableViscosity, 1) > 0 then if TinK then 1 ./ tableViscosity[:, 1] else 1 ./ Cv.from_degC(tableViscosity[:, 1]) else fill(0, neta) Type: Real[neta] |
poly_rho |
Value: if hasDensity then Polynomials.fitting(tableDensity[:, 1], tableDensity[:, 2], npolDensity) else zeros(npolDensity + 1) Type: Real[:] |
poly_Cp |
Value: if hasHeatCapacity then Polynomials.fitting(tableHeatCapacity[:, 1], tableHeatCapacity[:, 2], npolHeatCapacity) else zeros(npolHeatCapacity + 1) Type: Real[:] |
poly_eta |
Value: if hasViscosity then Polynomials.fitting(invTK, Math.log(tableViscosity[:, 2]), npolViscosity) else zeros(npolViscosity + 1) Type: Real[:] |
poly_pVap |
Value: if hasVaporPressure then Polynomials.fitting(tableVaporPressure[:, 1], tableVaporPressure[:, 2], npolVaporPressure) else zeros(npolVaporPressure + 1) Type: Real[:] |
poly_lam |
Value: if size(tableConductivity, 1) > 0 then Polynomials.fitting(tableConductivity[:, 1], tableConductivity[:, 2], npolConductivity) else zeros(npolConductivity + 1) Type: Real[:] |
This information is part of the Modelica Standard Library maintained by the Modelica Association.
This is the base package for medium models of incompressible fluids based on tables. The minimal data to provide for a useful medium description is tables of density and heat capacity as functions of temperature.
It should be noted that incompressible media only have 1 state per control volume (usually T), but have both T and p as inputs for fully correct properties. The error of using only T-dependent properties is small, therefore a Boolean flag enthalpyOfT exists. If it is true, the enumeration Choices.IndependentVariables is set to Choices.IndependentVariables.T otherwise it is set to Choices.IndependentVariables.pT.
To implement a new medium model, create a package that extends TableBased and provides one or more of the constant tables:
tableDensity = [T, d]; tableHeatCapacity = [T, Cp]; tableConductivity = [T, lam]; tableViscosity = [T, eta]; tableVaporPressure = [T, pVap];
The table data is used to fit constant polynomials of order npol, the temperature data points do not need to be same for different properties. Properties like enthalpy, inner energy and entropy are calculated consistently from integrals and derivatives of d(T) and Cp(T). The minimal data for a useful medium model is thus density and heat capacity. Transport properties and vapor pressure are optional, if the data tables are empty the corresponding function calls can not be used.
SystemModel["Modelica.Media.Incompressible.TableBased"]
Modelica.Media.Incompressible.Examples Essotherm thermal oil |
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Modelica.Media.Incompressible.Examples 1,2-Propylene glycol, 47% mixture with water |