| 1 | within Modelica.Media; |
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| 2 | package CompressibleLiquids "compressible liquid models" |
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| 3 | package Common "base classes for compressible liquids" |
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| 4 | extends Icons.Library; |
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| 5 | partial package LinearWater_pT |
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| 6 | "base class for liquid, linear compressibility water models" |
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| 7 | extends Media.Interfaces.PartialLinearFluid( |
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| 8 | constantJacobian=true, |
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| 9 | reference_d=Modelica.Media.Water.StandardWater.density(state), |
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| 10 | reference_h=Modelica.Media.Water.StandardWater.specificEnthalpy(state), |
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| 11 | reference_s=Modelica.Media.Water.StandardWater.specificEntropy(state), |
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| 12 | cp_const=Modelica.Media.Water.StandardWater.specificHeatCapacityCp(state), |
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| 13 | beta_const= |
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| 14 | Modelica.Media.Water.StandardWater.isobaricExpansionCoefficient(state), |
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| 15 | kappa_const=Modelica.Media.Water.StandardWater.isothermalCompressibility( |
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| 16 | state), |
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| 17 | MM_const=Modelica.Media.Water.StandardWater.molarMass(state)); |
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| 18 | |
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| 19 | constant Modelica.Media.Water.StandardWater.ThermodynamicState state= |
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| 20 | Modelica.Media.Water.StandardWater.setState_pT(reference_p, reference_T); |
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| 21 | end LinearWater_pT; |
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| 22 | end Common; |
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| 23 | |
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| 24 | package LinearColdWater "cold water model with linear compressibility" |
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| 25 | extends Media.Interfaces.PartialLinearFluid( |
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| 26 | constantJacobian=true, |
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| 27 | reference_p=101325, |
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| 28 | reference_T=278.15, |
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| 29 | reference_d=997.05, |
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| 30 | reference_h=104929, |
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| 31 | reference_s=100.0, |
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| 32 | cp_const=4181.9, |
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| 33 | beta_const=2.5713e-4, |
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| 34 | kappa_const=4.5154e-10, |
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| 35 | MM_const=0.018015268); |
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| 36 | |
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| 37 | redeclare function extends dynamicViscosity "Dynamic viscosity of water" |
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| 38 | algorithm |
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| 39 | eta := 0.15; |
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| 40 | end dynamicViscosity; |
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| 41 | |
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| 42 | redeclare function extends thermalConductivity |
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| 43 | "Thermal conductivity of water" |
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| 44 | algorithm |
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| 45 | lambda := 0.1; |
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| 46 | end thermalConductivity; |
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| 47 | |
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| 48 | end LinearColdWater; |
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| 49 | |
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| 50 | package LinearWater_pT_Ambient |
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| 51 | "liquid, linear compressibility water model at 1.01325 bar and 25 degree Celsius" |
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| 52 | extends Modelica.Media.CompressibleLiquids.Common.LinearWater_pT( |
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| 53 | reference_p = 101325, reference_T = 298.15); |
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| 54 | annotation (Documentation(info="<html> |
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| 55 | <h4>Water model with linear compressibility at ambient conditions</h4> |
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| 56 | </html>")); |
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| 57 | end LinearWater_pT_Ambient; |
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| 58 | |
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| 59 | annotation (Documentation(info="<html> |
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| 60 | |
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| 61 | <h4>Fluid models with linear compressibility, using PartialLinearFluid as base class.</h4> |
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| 62 | <p>The linear compressibility fluid models contained in this package are based on the assumptions that: |
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| 63 | </p> |
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| 64 | <ul> |
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| 65 | <li>The specific heat capacity at constant pressure (cp) is constant</li> |
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| 66 | <li>The isobaric expansion coefficient (beta) is constant</li> |
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| 67 | <li>The isothermal compressibility (kappa) is constant</li> |
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| 68 | <li>Pressure and temperature are used as states</li> |
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| 69 | </ul> |
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| 70 | <p> |
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| 71 | This results in models that are only valid for small temperature ranges, but sufficient to model compressibility and e.g. the \"water hammer\" effect. ANother advantage id that only 3 values need to be measured to have an initial model. Hydraulic fluids can often be approximated by this type of model. |
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| 72 | </p> |
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| 73 | <p> |
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| 74 | That means that the density is a linear function in temperature and in pressure. |
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| 75 | In order to define the complete model, a number of constant reference values are needed which |
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| 76 | are computed at the reference values of the states pressure p and temperature T. The model can |
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| 77 | be interprested as a linearization of a full non-linear fluid model (but it is not linear in all |
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| 78 | thermodynamic coordinates). Reference values are needed for |
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| 79 | </p> |
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| 80 | <ol> |
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| 81 | <li>the density (reference_d),</li> |
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| 82 | <li>the specific enthalpy (reference_h),</li> |
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| 83 | <li>the specific entropy (reference_s).</li> |
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| 84 | </ol> |
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| 85 | <p> |
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| 86 | Apart from that, a user needs to define the molar mass, MM_const. |
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| 87 | Note that it is possible to define a fluid by computing the reference |
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| 88 | values from a full non-linear fluid model by computing the package constants |
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| 89 | using the standard functions defined in a fluid package (see example in Common, LinearWater_pT). |
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| 90 | </p> |
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| 91 | |
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| 92 | </html>")); |
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| 93 | end CompressibleLiquids; |
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