.Modelica.Media.Water.WaterIF97_base

Information

This model calculates medium properties for water in the liquid, gas and two phase regions according to the IAPWS/IF97 standard, i.e., the accepted industrial standard and best compromise between accuracy and computation time. For more details see Modelica.Media.Water.IF97_Utilities. Three variable pairs can be the independent variables of the model:

  1. Pressure p and specific enthalpy h are the most natural choice for general applications. This is the recommended choice for most general purpose applications, in particular for power plants.
  2. Pressure p and temperature T are the most natural choice for applications where water is always in the same phase, both for liquid water and steam.
  3. Density d and temperature T are explicit variables of the Helmholtz function in the near-critical region and can be the best choice for applications with super-critical or near-critical states.

The following quantities are always computed:

Variable Unit Description
T K temperature
u J/kg specific internal energy
d kg/m^3 density
p Pa pressure
h J/kg specific enthalpy

In some cases additional medium properties are needed. A component that needs these optional properties has to call one of the functions listed in Modelica.Media.UsersGuide.MediumUsage.OptionalProperties and in Modelica.Media.UsersGuide.MediumUsage.TwoPhase.

Many further properties can be computed. Using the well-known Bridgman's Tables, all first partial derivatives of the standard thermodynamic variables can be computed easily.

Contents

NameDescription
 SaturationProperties
 ThermodynamicStateThermodynamic state
 BasePropertiesBase properties of water
 density_phComputes density as a function of pressure and specific enthalpy
 temperature_phComputes temperature as a function of pressure and specific enthalpy
 temperature_psCompute temperature from pressure and specific enthalpy
 density_psComputes density as a function of pressure and specific enthalpy
 pressure_dTComputes pressure as a function of density and temperature
 specificEnthalpy_dTComputes specific enthalpy as a function of density and temperature
 specificEnthalpy_pTComputes specific enthalpy as a function of pressure and temperature
 specificEnthalpy_psComputes specific enthalpy as a function of pressure and temperature
 density_pTComputes density as a function of pressure and temperature
 setDewStateSet the thermodynamic state on the dew line
 setBubbleStateSet the thermodynamic state on the bubble line
 dynamicViscosityDynamic viscosity of water
 thermalConductivityThermal conductivity of water
 surfaceTensionSurface tension in two phase region of water
 pressureReturn pressure of ideal gas
 temperatureReturn temperature of ideal gas
 densityReturn density of ideal gas
 specificEnthalpyReturn specific enthalpy
 specificInternalEnergyReturn specific internal energy
 specificGibbsEnergyReturn specific Gibbs energy
 specificHelmholtzEnergyReturn specific Helmholtz energy
 specificEntropySpecific entropy of water
 specificHeatCapacityCpSpecific heat capacity at constant pressure of water
 specificHeatCapacityCvSpecific heat capacity at constant volume of water
 isentropicExponentReturn isentropic exponent
 isothermalCompressibilityIsothermal compressibility of water
 isobaricExpansionCoefficientIsobaric expansion coefficient of water
 velocityOfSoundReturn velocity of sound as a function of the thermodynamic state record
 isentropicEnthalpyCompute h(s,p)
 density_derh_pDensity derivative by specific enthalpy
 density_derp_hDensity derivative by pressure
 bubbleEnthalpyBoiling curve specific enthalpy of water
 dewEnthalpyDew curve specific enthalpy of water
 bubbleEntropyBoiling curve specific entropy of water
 dewEntropyDew curve specific entropy of water
 bubbleDensityBoiling curve specific density of water
 dewDensityDew curve specific density of water
 saturationTemperatureSaturation temperature of water
 saturationTemperature_derpDerivative of saturation temperature w.r.t. pressure
 saturationPressureSaturation pressure of water
 dBubbleDensity_dPressureBubble point density derivative
 dDewDensity_dPressureDew point density derivative
 dBubbleEnthalpy_dPressureBubble point specific enthalpy derivative
 dDewEnthalpy_dPressureDew point specific enthalpy derivative
 setState_dTXReturn thermodynamic state of water as function of d, T, and optional region
 setState_phXReturn thermodynamic state of water as function of p, h, and optional region
 setState_psXReturn thermodynamic state of water as function of p, s, and optional region
 setState_pTXReturn thermodynamic state of water as function of p, T, and optional region
 setSmoothStateReturn thermodynamic state so that it smoothly approximates: if x > 0 then state_a else state_b

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