packageR134a_IIR_P1_395_T233_370_Record
Extends from AixLib.Media.Refrigerants.Interfaces.PartialHybridTwoPhaseMediumRecord (Base class for two phase medium using a hybrid approach with records).
Information
This package provides a refrigerant model for R134a using a hybrid approach developed by Sangi et al.. The hybrid approach is implemented in AixLib.Media.Refrigerants.Interfaces.PartialHybridTwoPhaseMediumRecord and the refrigerant model is implemented by complete the template AixLib.Media.Refrigerants.Interfaces.TemplateHybridTwoPhaseMediumRecord . The fitting coefficients required in the template are saved in the package AixLib.DataBase.Media.Refrigerants.R134a.
Assumptions and limitations
The implemented coefficients are fitted to external data by
Engelpracht and are valid within the following range:
|
Parameter |
Minimum Value |
Maximum Value |
|
Pressure (p) in bar |
1 |
39.5 |
|
Temperature (T) in K |
233.15 |
370.15 |
The reference point is defined as 200 kJ/kg and 1 kJ/kg/K, respectively, for enthalpy and entropy for the saturated liquid at 273.15 K.
Validation
The model is validated by comparing results obtained from the example model AixLib.Media.Refrigerants.Examples.RefrigerantProperties to external data (e.g. obtained from measurements or external media libraries).
References
Tillner-Roth, R.; Baehr, H. D. (1994): An International Standard Formulation for the thermodynamic Properties of 1,1,1,2|Tetrafluoroethane (HFC|134a) for Temperatures from 170 K to 455 K and Pressures up to 70 MPa. In: Journal of physical and chemical reference data (23), S. 657–729. DOI: 10.1063/1.555958 .
Huber, Marcia L.; Laesecke, Arno; Perkins, Richard A. (2003): Model for the Viscosity and Thermal Conductivity of Refrigerants, Including a New Correlation for the Viscosity of R134a. In: Ind. Eng. Chem. Res. 42 (13) , S. 3163–3178. DOI: 10.1021/ie0300880 .
Perkins, R. A.; Laesecke, A.; Howley, J.; Ramires, M. L. V.; Gurova, A. N.; Cusco, L. (2000): Experimental thermal conductivity values for the IUPAC round-robin sample of 1,1,1,2-tetrafluoroethane (R134a). Gaithersburg, MD: National Institute of Standards and Technology.
Mulero, A.; Cachadiña, I.; Parra, M. I. (2012): Recommended Correlations for the Surface Tension of Common Fluids. In: Journal of physical and chemical reference data 41 (4), S. 43105. DOI: 10.1063/1.4768782 .
Engelpracht, Mirko (2017): Development of modular and scalable simulation models for heat pumps and chillers considering various refrigerants. Master Thesis
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Media.Interfaces.PartialTwoPhaseMedium.FluidConstants | refrigerantConstants | Thermodynamic constants for R134a | |
| Modelica.Media.Interfaces.Choices.IndependentVariables | ThermoStates (from PartialMedium) | Enumeration type for independent variables | |
| String | mediumName (from PartialMedium) | "unusablePartialMedium" | Name of the medium |
| String[:] | substanceNames (from PartialMedium) | {mediumName} | Names of the mixture substances. Set substanceNames={mediumName} if only one substance. |
| String[:] | extraPropertiesNames (from PartialMedium) | fill("", 0) | Names of the additional (extra) transported properties. Set extraPropertiesNames=fill("",0) if unused |
| Boolean | singleState (from PartialMedium) | = true, if u and d are not a function of pressure | |
| Boolean | reducedX (from PartialMedium) | true | = true, if medium contains the equation sum(X) = 1.0; set reducedX=true, if only one substance (see docu for details) |
| Boolean | fixedX (from PartialMedium) | false | = true, if medium contains the equation X = reference_X |
| AbsolutePressure | reference_p (from PartialMedium) | 101325 | Reference pressure of Medium: default 1 atmosphere |
| Temperature | reference_T (from PartialMedium) | 298.15 | Reference temperature of Medium: default 25 deg Celsius |
| MassFraction[nX] | reference_X (from PartialMedium) | fill(1/nX, nX) | Default mass fractions of medium |
| AbsolutePressure | p_default (from PartialMedium) | 101325 | Default value for pressure of medium (for initialization) |
| Temperature | T_default (from PartialMedium) | Modelica.Units.Conversions.from_degC(20) | Default value for temperature of medium (for initialization) |
| SpecificEnthalpy | h_default (from PartialMedium) | specificEnthalpy_pTX(p_default, T_default, X_default) | Default value for specific enthalpy of medium (for initialization) |
| MassFraction[nX] | X_default (from PartialMedium) | reference_X | Default value for mass fractions of medium (for initialization) |
| ExtraProperty[nC] | C_default (from PartialMedium) | fill(0, nC) | Default value for trace substances of medium (for initialization) |
| Integer | nS (from PartialMedium) | size(substanceNames, 1) | Number of substances |
| Integer | nX (from PartialMedium) | nS | Number of mass fractions |
| Integer | nXi (from PartialMedium) | if fixedX then 0 else if reducedX then nS - 1 else nS | Number of structurally independent mass fractions (see docu for details) |
| Integer | nC (from PartialMedium) | size(extraPropertiesNames, 1) | Number of extra (outside of standard mass-balance) transported properties |
| Real[nC] | C_nominal (from PartialMedium) | 1.0e-6*ones(nC) | Default for the nominal values for the extra properties |
| Boolean | smoothModel (from PartialTwoPhaseMedium) | false | = true, if the (derived) model should not generate state events |
| Boolean | onePhase (from PartialTwoPhaseMedium) | false | = true, if the (derived) model should never be called with two-phase inputs |
| FluidConstants | fluidConstants (from PartialTwoPhaseMedium) | Constant data for the fluid |
Contents
| Name | Description |
|---|---|
 EoS | Record that contains fitting coefficients of the Helmholtz EoS |
 BDSP | Record that contains fitting coefficients of the state properties at bubble and dew lines |
 TSP | Record that contains fitting coefficients of the state properties calculated with two independent state properties |
| SmoothTransition | Record that contains ranges to calculate a smooth transition between different regions |
 dynamicViscosity | Calculates dynamic viscosity of refrigerant |
 thermalConductivity | Calculates thermal conductivity of refrigerant |
 surfaceTension | Surface tension in two phase region of refrigerant |
Revisions
- June 20, 2017, by Mirko Engelpracht, Christian Vering:
First implementation (see issue 408).