Modelica.Media.IdealGases.Common.Functions

Basic Functions for ideal gases: cp, h, s, thermal conductivity, viscosity

Information

Extends from Modelica.Icons.FunctionsPackage (Icon for packages containing functions).

Package Content

Name	Description
excludeEnthalpyOfFormation=true	If true, enthalpy of formation Hf is not included in specific enthalpy h
referenceChoice=Modelica.Media.Interfaces.Choices.ReferenceEnthalpy.ZeroAt0K	Choice of reference enthalpy
h_offset=0.0	User defined offset for reference enthalpy, if referenceChoice = UserDefined
methodForThermalConductivity=1
cp_T	Compute specific heat capacity at constant pressure from temperature and gas data
cp_Tlow	Compute specific heat capacity at constant pressure, low T region
cp_Tlow_der	Compute specific heat capacity at constant pressure, low T region
h_T	Compute specific enthalpy from temperature and gas data; reference is decided by the refChoice input, or by the referenceChoice package constant by default
h_T_der	Derivative function for h_T
h_Tlow	Compute specific enthalpy, low T region; reference is decided by the refChoice input, or by the referenceChoice package constant by default
h_Tlow_der	Compute specific enthalpy, low T region; reference is decided by the refChoice input, or by the referenceChoice package constant by default
s0_T	Compute specific entropy from temperature and gas data
s0_Tlow	Compute specific entropy, low T region
s0_Tlow_der	Compute derivative of specific entropy, low T region
dynamicViscosityLowPressure	Dynamic viscosity of low pressure gases
thermalConductivityEstimate	Thermal conductivity of polyatomic gases (Eucken and Modified Eucken correlation)

Modelica.Media.IdealGases.Common.Functions.cp_T

Compute specific heat capacity at constant pressure from temperature and gas data

Information

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Name	Description
data	Ideal gas data
T	Temperature [K]

Outputs

Name	Description
cp	Specific heat capacity at temperature T [J/(kg.K)]

Modelica.Media.IdealGases.Common.Functions.cp_Tlow

Compute specific heat capacity at constant pressure, low T region

Information

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Name	Description
data	Ideal gas data
T	Temperature [K]

Outputs

Name	Description
cp	Specific heat capacity at temperature T [J/(kg.K)]

Modelica.Media.IdealGases.Common.Functions.cp_Tlow_der

Compute specific heat capacity at constant pressure, low T region

Information

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Name	Description
data	Ideal gas data
T	Temperature [K]
dT	Temperature derivative

Outputs

Name	Description
cp_der	Derivative of specific heat capacity

Modelica.Media.IdealGases.Common.Functions.h_T

Compute specific enthalpy from temperature and gas data; reference is decided by the refChoice input, or by the referenceChoice package constant by default

Information

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Name	Description
data	Ideal gas data
T	Temperature [K]
exclEnthForm	If true, enthalpy of formation Hf is not included in specific enthalpy h
refChoice	Choice of reference enthalpy
h_off	User defined offset for reference enthalpy, if referenceChoice = UserDefined [J/kg]

Outputs

Name	Description
h	Specific enthalpy at temperature T [J/kg]

Modelica.Media.IdealGases.Common.Functions.h_T_der

Derivative function for h_T

Information

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Name	Description
data	Ideal gas data
T	Temperature [K]
exclEnthForm	If true, enthalpy of formation Hf is not included in specific enthalpy h
refChoice	Choice of reference enthalpy
h_off	User defined offset for reference enthalpy, if referenceChoice = UserDefined [J/kg]
dT	Temperature derivative

Outputs

Name	Description
h_der	Specific enthalpy at temperature T

Modelica.Media.IdealGases.Common.Functions.h_Tlow

Compute specific enthalpy, low T region; reference is decided by the refChoice input, or by the referenceChoice package constant by default

Information

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Name	Description
data	Ideal gas data
T	Temperature [K]
exclEnthForm	If true, enthalpy of formation Hf is not included in specific enthalpy h
refChoice	Choice of reference enthalpy
h_off	User defined offset for reference enthalpy, if referenceChoice = UserDefined [J/kg]

Outputs

Name	Description
h	Specific enthalpy at temperature T [J/kg]

Modelica.Media.IdealGases.Common.Functions.h_Tlow_der

Compute specific enthalpy, low T region; reference is decided by the refChoice input, or by the referenceChoice package constant by default

Information

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Name	Description
data	Ideal gas data
T	Temperature [K]
exclEnthForm	If true, enthalpy of formation Hf is not included in specific enthalpy h
refChoice	Choice of reference enthalpy
h_off	User defined offset for reference enthalpy, if referenceChoice = UserDefined [J/kg]
dT	Temperature derivative [K/s]

Outputs

Name	Description
h_der	Derivative of specific enthalpy at temperature T [J/(kg.s)]

Modelica.Media.IdealGases.Common.Functions.s0_T

Compute specific entropy from temperature and gas data

Information

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Name	Description
data	Ideal gas data
T	Temperature [K]

Outputs

Name	Description
s	Specific entropy at temperature T [J/(kg.K)]

Modelica.Media.IdealGases.Common.Functions.s0_Tlow

Compute specific entropy, low T region

Information

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Name	Description
data	Ideal gas data
T	Temperature [K]

Outputs

Name	Description
s	Specific entropy at temperature T [J/(kg.K)]

Modelica.Media.IdealGases.Common.Functions.s0_Tlow_der

Compute derivative of specific entropy, low T region

Information

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Name	Description
data	Ideal gas data
T	Temperature [K]
T_der	Temperature derivative [K/s]

Outputs

Name	Description
s_der	Derivative of specific entropy at temperature T [J/(kg.K.s)]

Modelica.Media.IdealGases.Common.Functions.dynamicViscosityLowPressure

Dynamic viscosity of low pressure gases

Information

The used formula are based on the method of Chung et al (1984, 1988) referred to in ref [1] chapter 9. The formula 9-4.10 is the one being used. The Formula is given in non-SI units, the following conversion constants were used to transform the formula to SI units:

Const1_SI: The factor 10^(-9.5) =10^(-2.5)*1e-7 where the factor 10^(-2.5) originates from the conversion of g/mol->kg/mol + cm^3/mol->m^3/mol and the factor 1e-7 is due to conversion from microPoise->Pa.s.
Const2_SI: The factor 1/3.335641e-27 = 1e-3/3.335641e-30 where the factor 3.335641e-30 comes from debye->C.m and 1e-3 is due to conversion from cm^3/mol->m^3/mol

References:

[1] Bruce E. Poling, John E. Prausnitz, John P. O'Connell, "The Properties of Gases and Liquids" 5th Ed. Mc Graw Hill.

Author

T. Skoglund, Lund, Sweden, 2004-08-31

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Name	Description
T	Gas temperature [K]
Tc	Critical temperature of gas [K]
M	Molar mass of gas [kg/mol]
Vc	Critical molar volume of gas [m3/mol]
w	Acentric factor of gas
mu	Dipole moment of gas molecule [debye]
k	Special correction for highly polar substances

Outputs

Name	Description
eta	Dynamic viscosity of gas [Pa.s]

Modelica.Media.IdealGases.Common.Functions.thermalConductivityEstimate

Thermal conductivity of polyatomic gases (Eucken and Modified Eucken correlation)

Information

This function provides two similar methods for estimating the thermal conductivity of polyatomic gases. The Eucken method (input method == 1) gives good results for low temperatures, but it tends to give an underestimated value of the thermal conductivity (lambda) at higher temperatures.
The Modified Eucken method (input method == 2) gives good results for high-temperatures, but it tends to give an overestimated value of the thermal conductivity (lambda) at low temperatures.

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Name	Description
Cp	Constant pressure heat capacity [J/(kg.K)]
eta	Dynamic viscosity [Pa.s]
method	1: Eucken Method, 2: Modified Eucken Method
data	Ideal gas data

Outputs

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

Automatically generated Thu Dec 19 17:20:17 2019.