From 8cc23d54bd373242c02fe53092cd0b6948b15368 Mon Sep 17 00:00:00 2001
From: andy <andy>
Date: Thu, 2 Aug 2012 14:29:11 +0100
Subject: [PATCH] ENH: Added new hurt-Mitchell C-oxidation model
---
.../makeCoalParcelSurfaceReactionModels.H | 4 +-
.../COxidationHurtMitchell.C | 206 ++++++++++++++++++
.../COxidationHurtMitchell.H | 184 ++++++++++++++++
3 files changed, 393 insertions(+), 1 deletion(-)
create mode 100644 src/lagrangian/coalCombustion/submodels/surfaceReactionModel/COxidationHurtMitchell/COxidationHurtMitchell.C
create mode 100644 src/lagrangian/coalCombustion/submodels/surfaceReactionModel/COxidationHurtMitchell/COxidationHurtMitchell.H
diff --git a/src/lagrangian/coalCombustion/include/makeCoalParcelSurfaceReactionModels.H b/src/lagrangian/coalCombustion/include/makeCoalParcelSurfaceReactionModels.H
index 37627758fff..2df26d9a3cd 100644
--- a/src/lagrangian/coalCombustion/include/makeCoalParcelSurfaceReactionModels.H
+++ b/src/lagrangian/coalCombustion/include/makeCoalParcelSurfaceReactionModels.H
@@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
- \\ / A nd | Copyright (C) 2011 OpenFOAM Foundation
+ \\ / A nd | Copyright (C) 2011-2012 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
@@ -31,6 +31,7 @@ License
#include "NoSurfaceReaction.H"
#include "COxidationDiffusionLimitedRate.H"
#include "COxidationKineticDiffusionLimitedRate.H"
+#include "COxidationHurtMitchell.H"
#include "COxidationMurphyShaddix.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
@@ -43,6 +44,7 @@ License
COxidationKineticDiffusionLimitedRate, \
CloudType \
); \
+ makeSurfaceReactionModelType(COxidationHurtMitchell, CloudType); \
makeSurfaceReactionModelType(COxidationMurphyShaddix, CloudType);
diff --git a/src/lagrangian/coalCombustion/submodels/surfaceReactionModel/COxidationHurtMitchell/COxidationHurtMitchell.C b/src/lagrangian/coalCombustion/submodels/surfaceReactionModel/COxidationHurtMitchell/COxidationHurtMitchell.C
new file mode 100644
index 00000000000..c3ecbbffafa
--- /dev/null
+++ b/src/lagrangian/coalCombustion/submodels/surfaceReactionModel/COxidationHurtMitchell/COxidationHurtMitchell.C
@@ -0,0 +1,206 @@
+/*---------------------------------------------------------------------------*\
+ ========= |
+ \\ / F ield | OpenFOAM: The Open Source CFD Toolbox
+ \\ / O peration |
+ \\ / A nd | Copyright (C) 2012 OpenFOAM Foundation
+ \\/ M anipulation |
+-------------------------------------------------------------------------------
+License
+ This file is part of OpenFOAM.
+
+ OpenFOAM is free software: you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
+
+\*---------------------------------------------------------------------------*/
+
+#include "COxidationHurtMitchell.H"
+#include "mathematicalConstants.H"
+
+// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
+
+template<class CloudType>
+Foam::COxidationHurtMitchell<CloudType>::COxidationHurtMitchell
+(
+ const dictionary& dict,
+ CloudType& owner
+)
+:
+ SurfaceReactionModel<CloudType>(dict, owner, typeName),
+ Sb_(readScalar(this->coeffDict().lookup("Sb"))),
+ CsLocalId_(-1),
+ ashLocalId_(-1),
+ O2GlobalId_(owner.composition().globalCarrierId("O2")),
+ CO2GlobalId_(owner.composition().globalCarrierId("CO2")),
+ WC_(0.0),
+ WO2_(0.0),
+ HcCO2_(0.0),
+ heatOfReaction_(-1.0)
+{
+ // Determine Cs and ash ids
+ label idSolid = owner.composition().idSolid();
+ CsLocalId_ = owner.composition().localId(idSolid, "C");
+ ashLocalId_ = owner.composition().localId(idSolid, "ash", true);
+
+ // Set local copies of thermo properties
+ WO2_ = owner.thermo().carrier().W(O2GlobalId_);
+ const scalar WCO2 = owner.thermo().carrier().W(CO2GlobalId_);
+ WC_ = WCO2 - WO2_;
+
+ HcCO2_ = owner.thermo().carrier().Hc(CO2GlobalId_);
+
+ const scalar YCloc = owner.composition().Y0(idSolid)[CsLocalId_];
+ const scalar YSolidTot = owner.composition().YMixture0()[idSolid];
+ Info<< " C(s): particle mass fraction = " << YCloc*YSolidTot << endl;
+
+ if (this->coeffDict().readIfPresent("heatOfReaction", heatOfReaction_))
+ {
+ Info<< " Using user specified heat of reaction: "
+ << heatOfReaction_ << " [J/kg]" << endl;
+ }
+}
+
+
+template<class CloudType>
+Foam::COxidationHurtMitchell<CloudType>::COxidationHurtMitchell
+(
+ const COxidationHurtMitchell<CloudType>& srm
+)
+:
+ SurfaceReactionModel<CloudType>(srm),
+ Sb_(srm.Sb_),
+ CsLocalId_(srm.CsLocalId_),
+ ashLocalId_(srm.ashLocalId_),
+ O2GlobalId_(srm.O2GlobalId_),
+ CO2GlobalId_(srm.CO2GlobalId_),
+ WC_(srm.WC_),
+ WO2_(srm.WO2_),
+ HcCO2_(srm.HcCO2_),
+ heatOfReaction_(srm.heatOfReaction_)
+{}
+
+
+// * * * * * * * * * * * * * * * * Destructor * * * * * * * * * * * * * * * //
+
+template<class CloudType>
+Foam::COxidationHurtMitchell<CloudType>::~COxidationHurtMitchell()
+{}
+
+
+// * * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * //
+
+template<class CloudType>
+Foam::scalar Foam::COxidationHurtMitchell<CloudType>::calculate
+(
+ const scalar dt,
+ const label cellI,
+ const scalar d,
+ const scalar T,
+ const scalar Tc,
+ const scalar pc,
+ const scalar rhoc,
+ const scalar mass,
+ const scalarField& YGas,
+ const scalarField& YLiquid,
+ const scalarField& YSolid,
+ const scalarField& YMixture,
+ const scalar N,
+ scalarField& dMassGas,
+ scalarField& dMassLiquid,
+ scalarField& dMassSolid,
+ scalarField& dMassSRCarrier
+) const
+{
+ const label idGas = CloudType::parcelType::GAS;
+ const label idSolid = CloudType::parcelType::SLD;
+ const scalar Ychar = YMixture[idSolid]*YSolid[CsLocalId_];
+
+ // Surface combustion until combustible fraction is consumed
+ if (Ychar < SMALL)
+ {
+ return 0.0;
+ }
+
+ const SLGThermo& thermo = this->owner().thermo();
+
+ // Local mass fraction of O2 in the carrier phase
+ const scalar YO2 = thermo.carrier().Y(O2GlobalId_)[cellI];
+
+ // No combustion if no oxygen present
+ if (YO2 < SMALL)
+ {
+ return 0.0;
+ }
+
+ // Conversion from [g/cm^2) to [kg/m^2]
+ const scalar convSI = 1000.0/10000.0;
+
+ // Universal gas constant in [kcal/mol/K]
+ const scalar RRcal = 1985.877534;
+
+ // Dry mass fraction
+ scalar Ydaf = YMixture[idGas] + YMixture[idSolid];
+ if (ashLocalId_ != -1)
+ {
+ Ydaf -= YMixture[idSolid]*YSolid[ashLocalId_];
+ }
+
+ // Char percentage
+ const scalar charPrc = Ychar/Ydaf*100.0;
+
+ // Particle surface area
+ const scalar Ap = constant::mathematical::pi*sqr(d);
+
+ // Far field partial pressure O2 [Pa]
+ // Note: Should really use the surface partial pressure
+ const scalar ppO2 = max(0.0, rhoc*YO2/WO2_*specie::RR*Tc);
+
+ // Activation energy [kcal/mol]
+ const scalar E = -5.94 + 0.355*charPrc;
+
+ // Pre-exponential factor [g/(cm^2.s.atm^0.5)]
+ const scalar lnK1750 = 2.8 - 0.0758*charPrc;
+ const scalar A = exp(lnK1750 + E/RRcal/1750.0);
+
+ // Kinetic rate of char oxidation [g/(cm^2.s.atm^0.5)]
+ const scalar Rk = A*exp(-E/(RRcal*T));
+
+ // Molar reaction rate per unit surface area [kmol/(m^2.s)]
+ const scalar qCsLim = mass*Ychar/(WC_*Ap*dt);
+ const scalar qCs = min(convSI*Rk*Foam::sqrt(ppO2/101325.0), qCsLim);
+
+ // Calculate the number of molar units reacted [kmol]
+ const scalar dOmega = qCs*Ap*dt;
+
+ // Add to carrier phase mass transfer
+ dMassSRCarrier[O2GlobalId_] += -dOmega*Sb_*WO2_;
+ dMassSRCarrier[CO2GlobalId_] += dOmega*(WC_ + Sb_*WO2_);
+
+ // Add to particle mass transfer
+ dMassSolid[CsLocalId_] += dOmega*WC_;
+
+
+ // Return the heat of reaction [J]
+ // note: carrier sensible enthalpy exchange handled via change in mass
+ if (heatOfReaction_ < 0)
+ {
+ const scalar HsC = thermo.solids().properties()[CsLocalId_].Hs(T);
+ return dOmega*(WC_*HsC - (WC_ + Sb_*WO2_)*HcCO2_);
+ }
+ else
+ {
+ return dOmega*WC_*heatOfReaction_;
+ }
+}
+
+
+// ************************************************************************* //
diff --git a/src/lagrangian/coalCombustion/submodels/surfaceReactionModel/COxidationHurtMitchell/COxidationHurtMitchell.H b/src/lagrangian/coalCombustion/submodels/surfaceReactionModel/COxidationHurtMitchell/COxidationHurtMitchell.H
new file mode 100644
index 00000000000..cd7800328fe
--- /dev/null
+++ b/src/lagrangian/coalCombustion/submodels/surfaceReactionModel/COxidationHurtMitchell/COxidationHurtMitchell.H
@@ -0,0 +1,184 @@
+/*---------------------------------------------------------------------------*\
+ ========= |
+ \\ / F ield | OpenFOAM: The Open Source CFD Toolbox
+ \\ / O peration |
+ \\ / A nd | Copyright (C) 2012 OpenFOAM Foundation
+ \\/ M anipulation |
+-------------------------------------------------------------------------------
+License
+ This file is part of OpenFOAM.
+
+ OpenFOAM is free software: you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
+
+Class
+ COxidationHurtMitchell
+
+Description
+ Char oxidation model given by Hurt and Mitchell:
+
+ Based on the reference:
+ Hurt R. and Mitchell R., "Unified high-temperature char combustion
+ kinetics for a suite of coals of various rank", 24th Symposium in
+ Combustion, The Combustion Institute, 1992, p 1243-1250
+
+ Model specifies the rate of char combustion.
+
+ C(s) + Sb*O2 -> CO2
+
+ where Sb is the stoichiometry of the reaction
+
+ Model validity:
+ Gas temperature: Tc > 1500 K
+ Particle sizes: 75 um -> 200 um
+ Pox > 0.3 atm
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef COxidationHurtMitchell_H
+#define COxidationHurtMitchell_H
+
+#include "SurfaceReactionModel.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+// Forward class declarations
+template<class CloudType>
+class COxidationHurtMitchell;
+
+/*---------------------------------------------------------------------------*\
+ Class COxidationHurtMitchell Declaration
+\*---------------------------------------------------------------------------*/
+
+template<class CloudType>
+class COxidationHurtMitchell
+:
+ public SurfaceReactionModel<CloudType>
+{
+ // Private data
+
+ // Model constants
+
+ //- Stoichiometry of reaction
+ const scalar Sb_;
+
+
+ // Addressing
+
+ //- Cs position in global/local lists
+ label CsLocalId_;
+
+ //- Ash position in global/local lists
+ label ashLocalId_;
+
+ //- O2 position in global list
+ label O2GlobalId_;
+
+ //- CO2 positions in global list
+ label CO2GlobalId_;
+
+
+ // Local copies of thermo properties
+
+ //- Molecular weight of C [kg/kmol]
+ scalar WC_;
+
+ //- Molecular weight of O2 [kg/kmol]
+ scalar WO2_;
+
+ //- Formation enthalpy for CO2 [J/kg]
+ scalar HcCO2_;
+
+ //- Heat of reaction [J/kg] (optional)
+ scalar heatOfReaction_;
+
+
+public:
+
+ //- Runtime type information
+ TypeName("COxidationHurtMitchell");
+
+
+ // Constructors
+
+ //- Construct from dictionary
+ COxidationHurtMitchell
+ (
+ const dictionary& dict,
+ CloudType& owner
+ );
+
+ //- Construct copy
+ COxidationHurtMitchell
+ (
+ const COxidationHurtMitchell<CloudType>& srm
+ );
+
+ //- Construct and return a clone
+ virtual autoPtr<SurfaceReactionModel<CloudType> > clone() const
+ {
+ return autoPtr<SurfaceReactionModel<CloudType> >
+ (
+ new COxidationHurtMitchell<CloudType>(*this)
+ );
+ }
+
+
+ //- Destructor
+ virtual ~COxidationHurtMitchell();
+
+
+ // Member Functions
+
+ //- Update surface reactions
+ virtual scalar calculate
+ (
+ const scalar dt,
+ const label cellI,
+ const scalar d,
+ const scalar T,
+ const scalar Tc,
+ const scalar pc,
+ const scalar rhoc,
+ const scalar mass,
+ const scalarField& YGas,
+ const scalarField& YLiquid,
+ const scalarField& YSolid,
+ const scalarField& YMixture,
+ const scalar N,
+ scalarField& dMassGas,
+ scalarField& dMassLiquid,
+ scalarField& dMassSolid,
+ scalarField& dMassSRCarrier
+ ) const;
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#ifdef NoRepository
+ #include "COxidationHurtMitchell.C"
+#endif
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //
--
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