Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.ThermodynamicState

Information

Modelica definition

redeclare record extends ThermodynamicState 
  "Thermodynamic state of ideal gas"
  AbsolutePressure p "Absolute pressure of medium";
  Temperature T "Temperature of medium";
end ThermodynamicState;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.FluidConstants

Information

Modelica definition

redeclare record extends FluidConstants "fluid constants"
end FluidConstants;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.BaseProperties

Information

This is the most simple incompressible medium model, where specific enthalpy h and specific internal energy u are only a function of temperature T and all other provided medium quantities are assumed to be constant.

Extends from .

Parameters

Type	Name	Default	Description
Advanced
Boolean	preferredMediumStates	false	= true if StateSelect.prefer shall be used for the independent property variables of the medium

Modelica definition

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)) 
  "Base properties of ideal gas"
equation 
      assert(T >= T_min and T <= T_max, "
Temperature T (= " + String(T) + " K) is not
in the allowed range (" + String(T_min) + " K <= T <= " + String(T_max)
         + " K)
required from medium model \"" + mediumName + "\".
");
  h = specificEnthalpy_pTX(p,T,X);
  u = h-R*T;
  R = R_gas;
  d = p/(R*T);
  MM = MM_const;
  state.T = T;
  state.p = p;
end BaseProperties;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.setState_pTX

Information

Inputs

Type	Name	Default	Description
AbsolutePressure	p		Pressure [Pa]
Temperature	T		Temperature [K]
MassFraction	X[:]	reference_X	Mass fractions [kg/kg]

Outputs

Type	Name	Description
ThermodynamicState	state	thermodynamic state record

Modelica definition

redeclare function setState_pTX 
  "Return thermodynamic state from p, T, and X or Xi"
  extends Modelica.Icons.Function;
  input AbsolutePressure p "Pressure";
  input Temperature T "Temperature";
  input MassFraction X[:]=reference_X "Mass fractions";
  output ThermodynamicState state "thermodynamic state record";
algorithm 
  state := ThermodynamicState(p=p,T=T);
end setState_pTX;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.setState_phX

Information

Inputs

Type	Name	Default	Description
AbsolutePressure	p		Pressure [Pa]
SpecificEnthalpy	h		Specific enthalpy [J/kg]
MassFraction	X[:]	reference_X	Mass fractions [kg/kg]

Outputs

Type	Name	Description
ThermodynamicState	state	thermodynamic state record

Modelica definition

redeclare function setState_phX 
  "Return thermodynamic state from p, h, and X or Xi"
  extends Modelica.Icons.Function;
  input AbsolutePressure p "Pressure";
  input SpecificEnthalpy h "Specific enthalpy";
  input MassFraction X[:]=reference_X "Mass fractions";
  output ThermodynamicState state "thermodynamic state record";
algorithm 
  state := ThermodynamicState(p=p,T=T0+h/cp_const);
end setState_phX;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.setState_psX

Information

Inputs

Type	Name	Default	Description
AbsolutePressure	p		Pressure [Pa]
SpecificEntropy	s		Specific entropy [J/(kg.K)]
MassFraction	X[:]	reference_X	Mass fractions [kg/kg]

Outputs

Type	Name	Description
ThermodynamicState	state	thermodynamic state record

Modelica definition

redeclare replaceable function setState_psX 
  "Return thermodynamic state from p, s, and X or Xi"
  extends Modelica.Icons.Function;
  input AbsolutePressure p "Pressure";
  input SpecificEntropy s "Specific entropy";
  input MassFraction X[:]=reference_X "Mass fractions";
  output ThermodynamicState state "thermodynamic state record";
algorithm 
  state := ThermodynamicState(p=p,T=Modelica.Math.exp(s/cp_const + Modelica.Math.log(reference_T))
                              + R_gas*Modelica.Math.log(p/reference_p));
end setState_psX;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.setState_dTX

Information

Inputs

Type	Name	Default	Description
Density	d		density [kg/m3]
Temperature	T		Temperature [K]
MassFraction	X[:]	reference_X	Mass fractions [kg/kg]

Outputs

Type	Name	Description
ThermodynamicState	state	thermodynamic state record

Modelica definition

redeclare function setState_dTX 
  "Return thermodynamic state from d, T, and X or Xi"
  extends Modelica.Icons.Function;
  input Density d "density";
  input Temperature T "Temperature";
  input MassFraction X[:]=reference_X "Mass fractions";
  output ThermodynamicState state "thermodynamic state record";
algorithm 
  state := ThermodynamicState(p=d*R_gas*T,T=T);
end setState_dTX;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.setSmoothState

Information

Inputs

Type	Name	Default	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

Outputs

Type	Name	Description
ThermodynamicState	state	Smooth thermodynamic state for all x (continuous and differentiable)

Modelica definition

redeclare function extends setSmoothState 
  "Return thermodynamic state so that it smoothly approximates: if x > 0 then state_a else state_b"
algorithm 
  state := ThermodynamicState(p=Media.Common.smoothStep(x, state_a.p, state_b.p, x_small),
                              T=Media.Common.smoothStep(x, state_a.T, state_b.T, x_small));
end setSmoothState;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.pressure

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
AbsolutePressure	p	Pressure [Pa]

Modelica definition

redeclare function extends pressure "Return pressure of ideal gas"

algorithm 
  p := state.p;
end pressure;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.temperature

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
Temperature	T	Temperature [K]

Modelica definition

redeclare function extends temperature 
  "Return temperature of ideal gas"

algorithm 
  T := state.T;
end temperature;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.density

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
Density	d	Density [kg/m3]

Modelica definition

redeclare function extends density "Return density of ideal gas"
algorithm 
  d := state.p/(R_gas*state.T);
end density;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.specificEnthalpy

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
SpecificEnthalpy	h	Specific enthalpy [J/kg]

Modelica definition

redeclare function extends specificEnthalpy 
  "Return specific enthalpy"
    extends Modelica.Icons.Function;
algorithm 
  h := cp_const*(state.T-T0);
end specificEnthalpy;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.specificInternalEnergy

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
SpecificEnergy	u	Specific internal energy [J/kg]

Modelica definition

redeclare function extends specificInternalEnergy 
  "Return specific internal energy"
  extends Modelica.Icons.Function;
algorithm 
  // u := (cp_const-R_gas)*(state.T-T0);
  u := cp_const*(state.T-T0) - R_gas*state.T;
end specificInternalEnergy;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.specificEntropy

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
SpecificEntropy	s	Specific entropy [J/(kg.K)]

Modelica definition

redeclare function extends specificEntropy "Return specific entropy"
    extends Modelica.Icons.Function;
algorithm 
  s := cp_const*Modelica.Math.log(state.T/T0) - R_gas*Modelica.Math.log(state.p/reference_p);
end specificEntropy;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.specificGibbsEnergy

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
SpecificEnergy	g	Specific Gibbs energy [J/kg]

Modelica definition

redeclare function extends specificGibbsEnergy 
  "Return specific Gibbs energy"
  extends Modelica.Icons.Function;
algorithm 
  g := cp_const*(state.T-T0) - state.T*specificEntropy(state);
end specificGibbsEnergy;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.specificHelmholtzEnergy

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
SpecificEnergy	f	Specific Helmholtz energy [J/kg]

Modelica definition

redeclare function extends specificHelmholtzEnergy 
  "Return specific Helmholtz energy"
  extends Modelica.Icons.Function;
algorithm 
  f := (cp_const-R_gas)*(state.T-T0) - state.T*specificEntropy(state);
end specificHelmholtzEnergy;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.dynamicViscosity

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
DynamicViscosity	eta	Dynamic viscosity [Pa.s]

Modelica definition

redeclare function extends dynamicViscosity 
  "Return dynamic viscosity"

algorithm 
  eta := eta_const;
end dynamicViscosity;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.thermalConductivity

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
ThermalConductivity	lambda	Thermal conductivity [W/(m.K)]

Modelica definition

redeclare function extends thermalConductivity 
  "Return thermal conductivity"

algorithm 
  lambda := lambda_const;
end thermalConductivity;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.specificHeatCapacityCp

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
SpecificHeatCapacity	cp	Specific heat capacity at constant pressure [J/(kg.K)]

Modelica definition

redeclare function extends specificHeatCapacityCp 
  "Return specific heat capacity at constant pressure"

algorithm 
  cp := cp_const;
end specificHeatCapacityCp;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.specificHeatCapacityCv

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
SpecificHeatCapacity	cv	Specific heat capacity at constant volume [J/(kg.K)]

Modelica definition

redeclare function extends specificHeatCapacityCv 
  "Return specific heat capacity at constant volume"

algorithm 
  cv := cv_const;
end specificHeatCapacityCv;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.isentropicExponent

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
IsentropicExponent	gamma	Isentropic exponent [1]

Modelica definition

redeclare function extends isentropicExponent 
  "Return isentropic exponent"

algorithm 
  gamma := cp_const/cv_const;
end isentropicExponent;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.velocityOfSound

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
VelocityOfSound	a	Velocity of sound [m/s]

Modelica definition

redeclare function extends velocityOfSound 
  "Return velocity of sound "

algorithm 
  a := sqrt(cp_const/cv_const*R_gas*state.T);
end velocityOfSound;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.specificEnthalpy_pTX

Information

Inputs

Type	Name	Default	Description
AbsolutePressure	p		Pressure [Pa]
Temperature	T		Temperature [K]
MassFraction	X[nX]		Mass fractions [kg/kg]

Outputs

Type	Name	Description
SpecificEnthalpy	h	Specific enthalpy at p, T, X [J/kg]

Modelica definition

redeclare function specificEnthalpy_pTX 
  "Return specific enthalpy from p, T, and X or Xi"
  extends Modelica.Icons.Function;
  input AbsolutePressure p "Pressure";
  input Temperature T "Temperature";
  input MassFraction X[nX] "Mass fractions";
  output SpecificEnthalpy h "Specific enthalpy at p, T, X";
algorithm 
  h := cp_const*(T-T0);
end specificEnthalpy_pTX;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.temperature_phX

Information

Inputs

Type	Name	Default	Description
AbsolutePressure	p		Pressure [Pa]
SpecificEnthalpy	h		Specific enthalpy [J/kg]
MassFraction	X[nX]		Mass fractions [kg/kg]

Outputs

Type	Name	Description
Temperature	T	Temperature [K]

Modelica definition

redeclare function temperature_phX 
  "Return temperature from p, h, and X or Xi"
  extends Modelica.Icons.Function;
  input AbsolutePressure p "Pressure";
  input SpecificEnthalpy h "Specific enthalpy";
  input MassFraction X[nX] "Mass fractions";
  output Temperature T "Temperature";
algorithm 
  T := h/cp_const + T0;
end temperature_phX;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.density_phX

Information

Inputs

Type	Name	Default	Description
AbsolutePressure	p		Pressure [Pa]
SpecificEnthalpy	h		Specific enthalpy [J/kg]
MassFraction	X[nX]		Mass fractions [kg/kg]

Outputs

Type	Name	Description
Density	d	density [kg/m3]

Modelica definition

redeclare function density_phX 
  "Return density from p, h, and X or Xi"
  extends Modelica.Icons.Function;
  input AbsolutePressure p "Pressure";
  input SpecificEnthalpy h "Specific enthalpy";
  input MassFraction X[nX] "Mass fractions";
  output Density d "density";
algorithm 
  d := density(setState_phX(p,h,X));
end density_phX;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.isentropicEnthalpy

Information

Inputs

Type	Name	Default	Description
AbsolutePressure	p_downstream		downstream pressure [Pa]
ThermodynamicState	refState		reference state for entropy

Outputs

Type	Name	Description
SpecificEnthalpy	h_is	Isentropic enthalpy [J/kg]

Modelica definition

redeclare function extends isentropicEnthalpy 
  "Return isentropic enthalpy"
algorithm 
  /*  s = cp_const*log(refState.T/T0) - R_gas*log(refState.p/reference_p)
          = cp_const*log(state.T/T0) - R_gas*log(p_downstream/reference_p)

        log(state.T) = log(refState.T) +
                       (R_gas/cp_const)*(log(p_downstream/reference_p) - log(refState.p/reference_p))
                     = log(refState.T) + (R_gas/cp_const)*log(p_downstream/refState.p)
                     = log(refState.T) + log( (p_downstream/refState.p)^(R_gas/cp_const) )
                     = log( refState.T*(p_downstream/refState.p)^(R_gas/cp_const) )
        state.T = refstate.T*(p_downstream/refstate.p)^(R_gas/cp_const)
    */
  h_is := cp_const*(refState.T*(p_downstream/refState.p)^(R_gas/cp_const) - T0);
end isentropicEnthalpy;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.isobaricExpansionCoefficient

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
IsobaricExpansionCoefficient	beta	Isobaric expansion coefficient [1/K]

Modelica definition

redeclare function extends isobaricExpansionCoefficient 
  "Returns overall the isobaric expansion coefficient beta"
algorithm 
  /* beta = 1/v * der(v,T), with v = 1/d, at constant pressure p:
       v = R*T/p
       der(v,T) = R/p
       beta = p/(R*T)*R/p
            = 1/T
    */

  beta := 1/state.T;
end isobaricExpansionCoefficient;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.isothermalCompressibility

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
IsothermalCompressibility	kappa	Isothermal compressibility [1/Pa]

Modelica definition

redeclare function extends isothermalCompressibility 
  "Returns overall the isothermal compressibility factor"
algorithm 
  /* kappa = - 1/v * der(v,p), with v = 1/d at constant temperature T.
       v = R*T/p
       der(v,T) = -R*T/p^2
       kappa = p/(R*T)*R*T/p^2
             = 1/p
    */
  kappa := 1/state.p;
end isothermalCompressibility;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.density_derp_T

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
DerDensityByPressure	ddpT	Density derivative w.r.t. pressure [s2/m2]

Modelica definition

redeclare function extends density_derp_T 
  "Returns the partial derivative of density with respect to pressure at constant temperature"
algorithm 
  /*  d = p/(R*T)
        ddpT = 1/(R*T)
    */
  ddpT := 1/(R_gas*state.T);
end density_derp_T;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.density_derT_p

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
DerDensityByTemperature	ddTp	Density derivative w.r.t. temperature [kg/(m3.K)]

Modelica definition

redeclare function extends density_derT_p 
  "Returns the partial derivative of density with respect to temperature at constant pressure"
algorithm 
  /*  d = p/(R*T)
        ddpT = -p/(R*T^2)
    */
  ddTp := -state.p/(R_gas*state.T*state.T);
end density_derT_p;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.density_derX

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
Density	dddX[nX]	Derivative of density w.r.t. mass fraction [kg/m3]

Modelica definition

redeclare function extends density_derX 
  "Returns the partial derivative of density with respect to mass fractions at constant pressure and temperature"
algorithm 
  dddX := fill(0,nX);
end density_derX;

Modelica.Media.Interfaces.PartialSimpleIdealGasMedium.molarMass

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
MolarMass	MM	Mixture molar mass [kg/mol]

Modelica definition

redeclare function extends molarMass 
  "Returns the molar mass of the medium"
algorithm 
  MM := MM_const;
end molarMass;