packageR134a_IIR_P1_395_T233_455_Formula
Extends from AixLib.Media.Refrigerants.Interfaces.PartialHybridTwoPhaseMediumFormula (Base class for two phase medium using a hybrid approach without 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.PartialHybridTwoPhaseMediumFormula and the refrigerant model is implemented by complete the template AixLib.Media.Refrigerants.Interfaces.TemplateHybridTwoPhaseMediumFormula .
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 |
455.15 |
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 |
|---|---|
| SmoothTransition | Record that contains ranges to calculate a smooth transition between different regions |
| f_Idg | Dimensionless Helmholtz energy (Ideal gas contribution alpha_0) |
| f_Res | Dimensionless Helmholtz energy (Residual part alpha_r) |
| t_fIdg_t | Short form for tau*(dalpha_0/dtau)_delta=const |
| tt_fIdg_tt | Short form for tau*tau*(ddalpha_0/(dtau*dtau))_delta=const |
| t_fRes_t | Short form for tau*(dalpha_r/dtau)_delta=const |
| tt_fRes_tt | Short form for tau*tau*(ddalpha_r/(dtau*dtau))_delta=const |
| d_fRes_d | Short form for delta*(dalpha_r/(ddelta))_tau=const |
| dd_fRes_dd | Short form for delta*delta(ddalpha_r/(ddelta*delta))_tau=const |
| td_fRes_td | Short form for tau*delta*(ddalpha_r/(dtau*ddelta)) |
| ttt_fIdg_ttt | Short form for tau*tau*tau*(dddalpha_0/(dtau*dtau*dtau))_delta=const |
| ttt_fRes_ttt | Short form for tau*tau*tau*(dddalpha_r/(dtau*dtau*dtau))_delta=const |
| ddd_fRes_ddd | Short form for delta*delta*delta* (dddalpha_r/(ddelta*ddelta*ddelta))_tau=const |
| tdd_fRes_tdd | Short form for tau*delta*delta*(dddalpha_r/(dtau*ddelta*ddelta)) |
| ttd_fRes_ttd | Short form for tau*tau*delta*(dddalpha_r/(dtau*dtau*ddelta)) |
 saturationPressure | Saturation pressure of refrigerant (Ancillary equation) |
 saturationTemperature | Saturation temperature of refrigerant (Ancillary equation) |
 bubbleDensity | Boiling curve specific density of refrigerant (Ancillary equation) |
 dewDensity | Dew curve specific density of refrigerant (Ancillary equation) |
 bubbleEnthalpy | Boiling curve specific enthalpy of refrigerant (Ancillary equation) |
 dewEnthalpy | Dew curve specific enthalpy of refrigerant (Ancillary equation) |
 bubbleEntropy | Boiling curve specific entropy of refrigerant (Ancillary equation) |
 dewEntropy | Dew curve specific entropy of propane (Ancillary equation) |
 temperature_ph | Calculates temperature as function of pressure and specific enthalpy |
 temperature_ps | Calculates temperature as function of pressure and specific entroy |
 density_pT | Computes density as a function of pressure and temperature |
 dynamicViscosity | Calculates dynamic viscosity of refrigerant |
 thermalConductivity | Calculates thermal conductivity of refrigerant |
 surfaceTension | Surface tension in two phase region of refrigerant |
Revisions
- September 06, 2017, by Mirko Engelpracht, Christian Vering:
First implementation (see issue 408).