From f69343e7c44ccbc89fcd7984b58cf9cfe1d4e4f0 Mon Sep 17 00:00:00 2001
From: Klaus Mosthaf <klmos@env.dtu.dk>
Date: Fri, 16 Nov 2012 16:06:49 +0000
Subject: [PATCH] Added first approximation for the thermalConductivity in the
h2oairfluidsystem. As a first step, this is valid only for 0.1 MPa and
293.15K. However, the complex formulation for conductivity of h2o is computed
correctly. TODO: It has to be generalized for different
pressures/temperatures and the air conductivity has to be averaged somehow
due to its composition.
Reviewed by Markus
git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@9574 2fb0f335-1f38-0410-981e-8018bf24f1b0
---
.../fluidsystems/h2oairfluidsystem.hh | 85 ++++++++++++++++++-
1 file changed, 83 insertions(+), 2 deletions(-)
diff --git a/dumux/material/fluidsystems/h2oairfluidsystem.hh b/dumux/material/fluidsystems/h2oairfluidsystem.hh
index 759949a18b..2e6935fbc2 100644
--- a/dumux/material/fluidsystems/h2oairfluidsystem.hh
+++ b/dumux/material/fluidsystems/h2oairfluidsystem.hh
@@ -137,7 +137,7 @@ public:
*
* We define an ideal mixture as a fluid phase where the fugacity
* coefficients of all components times the pressure of the phase
- * are indepent on the fluid composition. This assumption is true
+ * are independent on the fluid composition. This assumption is true
* if Henry's law and Rault's law apply. If you are unsure what
* this function should return, it is safe to return false. The
* only damage done will be (slightly) increased computation times
@@ -664,7 +664,49 @@ public:
static Scalar thermalConductivity(const FluidState &fluidState,
int phaseIdx)
{
- DUNE_THROW(Dune::NotImplemented, "FluidSystems::H2OAir::thermalConductivity()");
+ // PRELIMINARY, values for 293.15 K - has to be generalized
+ assert(0 <= phaseIdx && phaseIdx < numPhases);
+
+ if (phaseIdx == wPhaseIdx){// liquid phase
+ if(useComplexRelations){
+ const Scalar temperature = fluidState.temperature(phaseIdx) ;
+ const Scalar pressure = fluidState.pressure(phaseIdx);
+ return H2O::liquidThermalConductivity(temperature, pressure);
+ }
+ else
+ // Database of National Institute of Standards and Technology
+ // Isobaric conductivity at 293.15 K
+ return 0.59848; // conductivity of liquid water[W / (m K ) ]
+ }
+ else{// gas phase
+ // Isobaric Properties for Nitrogen in: NIST Standard
+ // see http://webbook.nist.gov/chemistry/fluid/
+ // evaluated at p=.1 MPa, T=20°C
+ // Nitrogen: 0.025398
+ // Oxygen: 0.026105
+ // lambda_air is approximately 0.78*lambda_N2+0.22*lambda_O2
+ const Scalar lambdaPureAir = 0.0255535;
+
+//TODO: arithmetic mean correct? partial pressure for lambdaH2O?
+// if (useComplexRelations){
+// Scalar xAir = fluidState.moleFraction(phaseIdx, AirIdx);
+// Scalar xH2O = fluidState.moleFraction(phaseIdx, H2OIdx);
+// Scalar lambdaAir = xAir * lambdaPureAir;
+//
+// // Assuming Raoult's, Daltons law and ideal gas
+// // in order to obtain the partial density of water in the air phase
+// const Scalar temperature = fluidState.temperature(phaseIdx) ;
+// const Scalar pressure = fluidState.pressure(phaseIdx);
+// const Scalar partialPressure = pressure * xH2O;
+//
+// // thermal conductivity of vapor
+// Scalar lambdaH2O = H2O::gasThermalConductivity(temperature, partialPressure);
+//
+// return lambdaAir + lambdaH2O;
+// }
+// else
+ return lambdaPureAir; // conductivity of pure air [W/(m K)]
+ }
}
/*!
@@ -680,6 +722,45 @@ public:
int phaseIdx)
{
DUNE_THROW(Dune::NotImplemented, "FluidSystems::H2OAir::heatCapacity()");
+// if (phaseIdx == wPhaseIdx) {
+// return H2O::liquidHeatCapacity(fluidState.temperature(phaseIdx),
+// fluidState.pressure(phaseIdx));
+// }
+//
+// // for the gas phase, assume ideal mixture, i.e. molecules of
+// // one component don't "see" the molecules of the other
+// // component
+//
+// Scalar c_pN2;
+// Scalar c_pH2O;
+// // let the water and nitrogen components do things their own way
+// if (useComplexRelations) {
+// c_pN2 = N2::gasHeatCapacity(fluidState.temperature(phaseIdx),
+// fluidState.pressure(phaseIdx)
+// * fluidState.moleFraction(phaseIdx, AirIdx));
+//
+// c_pH2O = H2O::gasHeatCapacity(fluidState.temperature(phaseIdx),
+// fluidState.pressure(phaseIdx)
+// * fluidState.moleFraction(phaseIdx, H2OIdx));
+// }
+// else {
+// // assume an ideal gas for both components. See:
+// //
+// // http://en.wikipedia.org/wiki/Heat_capacity
+// Scalar c_vN2molar = Dumux::Constants<Scalar>::R*2.39;
+// Scalar c_pN2molar = Dumux::Constants<Scalar>::R + c_vN2molar;
+//
+// Scalar c_vH2Omolar = Dumux::Constants<Scalar>::R*3.37; // <- correct??
+// Scalar c_pH2Omolar = Dumux::Constants<Scalar>::R + c_vH2Omolar;
+//
+// c_pN2 = c_pN2molar/molarMass(AirIdx);
+// c_pH2O = c_pH2Omolar/molarMass(H2OIdx);
+// }
+//
+// // mangle both components together
+// return
+// c_pH2O*fluidState.massFraction(nPhaseIdx, H2OIdx)
+// + c_pN2*fluidState.massFraction(nPhaseIdx, AirIdx);
}
};
--
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