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https://develop.openfoam.com/Development/openfoam.git
synced 2025-11-28 03:28:01 +00:00
ENH: Coal combustion - added new intrinsic rate surface oxidation model
This commit is contained in:
andy
@ -2,7 +2,7 @@
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========= |
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\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
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\\ / O peration |
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\\ / A nd | Copyright (C) 2011-2012 OpenFOAM Foundation
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\\ / A nd | Copyright (C) 2011-2014 OpenFOAM Foundation
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\\/ M anipulation |
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-------------------------------------------------------------------------------
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License
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@ -30,6 +30,7 @@ License
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#include "NoSurfaceReaction.H"
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#include "COxidationDiffusionLimitedRate.H"
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#include "COxidationIntrinsicRate.H"
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#include "COxidationKineticDiffusionLimitedRate.H"
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#include "COxidationHurtMitchell.H"
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#include "COxidationMurphyShaddix.H"
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@ -44,6 +45,7 @@ License
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COxidationKineticDiffusionLimitedRate, \
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CloudType \
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); \
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makeSurfaceReactionModelType(COxidationIntrinsicRate, CloudType); \
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makeSurfaceReactionModelType(COxidationHurtMitchell, CloudType); \
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makeSurfaceReactionModelType(COxidationMurphyShaddix, CloudType);
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@ -0,0 +1,228 @@
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/*---------------------------------------------------------------------------*\
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========= |
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\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
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\\ / O peration |
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\\ / A nd | Copyright (C) 2013-2014 OpenCFD Ltd.
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\\/ M anipulation |
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-------------------------------------------------------------------------------
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License
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This file is part of OpenFOAM.
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OpenFOAM is free software: you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
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\*---------------------------------------------------------------------------*/
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#include "COxidationIntrinsicRate.H"
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#include "mathematicalConstants.H"
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using namespace Foam::constant;
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// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
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template<class CloudType>
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Foam::COxidationIntrinsicRate<CloudType>::COxidationIntrinsicRate
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(
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const dictionary& dict,
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CloudType& owner
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)
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:
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SurfaceReactionModel<CloudType>(dict, owner, typeName),
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Sb_(readScalar(this->coeffDict().lookup("Sb"))),
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C1_(readScalar(this->coeffDict().lookup("C1"))),
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rMean_(readScalar(this->coeffDict().lookup("rMean"))),
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theta_(readScalar(this->coeffDict().lookup("theta"))),
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Ai_(readScalar(this->coeffDict().lookup("Ai"))),
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Ei_(readScalar(this->coeffDict().lookup("Ei"))),
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Ag_(readScalar(this->coeffDict().lookup("Ag"))),
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tau_(this->coeffDict().lookupOrDefault("tau", sqrt(2.0))),
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CsLocalId_(-1),
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O2GlobalId_(owner.composition().globalCarrierId("O2")),
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CO2GlobalId_(owner.composition().globalCarrierId("CO2")),
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WC_(0.0),
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WO2_(0.0),
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HcCO2_(0.0)
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{
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// Determine Cs ids
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label idSolid = owner.composition().idSolid();
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CsLocalId_ = owner.composition().localId(idSolid, "C");
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// Set local copies of thermo properties
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WO2_ = owner.thermo().carrier().W(O2GlobalId_);
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const scalar WCO2 = owner.thermo().carrier().W(CO2GlobalId_);
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WC_ = WCO2 - WO2_;
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HcCO2_ = owner.thermo().carrier().Hc(CO2GlobalId_);
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if (Sb_ < 0)
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{
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FatalErrorIn
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(
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"COxidationIntrinsicRate<CloudType>"
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"("
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"const dictionary&, "
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"CloudType&"
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")"
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) << "Stoichiometry of reaction, Sb, must be greater than zero" << nl
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<< exit(FatalError);
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}
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const scalar YCloc = owner.composition().Y0(idSolid)[CsLocalId_];
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const scalar YSolidTot = owner.composition().YMixture0()[idSolid];
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Info<< " C(s): particle mass fraction = " << YCloc*YSolidTot << endl;
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}
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template<class CloudType>
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Foam::COxidationIntrinsicRate<CloudType>::COxidationIntrinsicRate
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(
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const COxidationIntrinsicRate<CloudType>& srm
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)
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:
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SurfaceReactionModel<CloudType>(srm),
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Sb_(srm.Sb_),
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C1_(srm.C1_),
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rMean_(srm.rMean_),
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theta_(srm.theta_),
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Ai_(srm.Ai_),
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Ei_(srm.Ei_),
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Ag_(srm.Ag_),
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tau_(srm.tau_),
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CsLocalId_(srm.CsLocalId_),
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O2GlobalId_(srm.O2GlobalId_),
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CO2GlobalId_(srm.CO2GlobalId_),
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WC_(srm.WC_),
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WO2_(srm.WO2_),
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HcCO2_(srm.HcCO2_)
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{}
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// * * * * * * * * * * * * * * * * Destructor * * * * * * * * * * * * * * * //
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template<class CloudType>
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Foam::COxidationIntrinsicRate<CloudType>::
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~COxidationIntrinsicRate()
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{}
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// * * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * //
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template<class CloudType>
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Foam::scalar Foam::COxidationIntrinsicRate<CloudType>::calculate
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(
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const scalar dt,
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const label cellI,
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const scalar d,
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const scalar T,
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const scalar Tc,
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const scalar pc,
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const scalar rhoc,
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const scalar mass,
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const scalarField& YGas,
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const scalarField& YLiquid,
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const scalarField& YSolid,
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const scalarField& YMixture,
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const scalar N,
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scalarField& dMassGas,
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scalarField& dMassLiquid,
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scalarField& dMassSolid,
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scalarField& dMassSRCarrier
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) const
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{
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// Fraction of remaining combustible material
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const label idSolid = CloudType::parcelType::SLD;
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const scalar Ychar = YMixture[idSolid]*YSolid[CsLocalId_];
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// Surface combustion until combustible fraction is consumed
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if (Ychar < SMALL)
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{
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return 0.0;
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}
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const SLGThermo& thermo = this->owner().thermo();
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// Local mass fraction of O2 in the carrier phase []
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const scalar YO2 = thermo.carrier().Y(O2GlobalId_)[cellI];
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// Quick exit if oxidant not present
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if (YO2 < ROOTVSMALL)
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{
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return 0.0;
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}
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// Diffusion rate coefficient [m2/s]
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const scalar D0 = C1_/d*pow(0.5*(T + Tc), 0.75);
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// Apparent density of pyrolysis char [kg/m3]
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const scalar rhop = 6.0*mass/(constant::mathematical::pi*pow3(d));
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// Knusden diffusion coefficient [m2/s]
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const scalar Dkn = 97.0*rMean_*sqrt(T/WO2_);
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// Effective diffusion [m2/s]
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const scalar De = theta_/sqr(tau_)/(1.0/Dkn + 1/D0);
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// Cell carrier phase O2 species density [kg/m^3]
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const scalar rhoO2 = rhoc*YO2;
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// Partial pressure O2 [Pa]
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const scalar ppO2 = rhoO2/WO2_*specie::RR*Tc;
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// Intrinsic reactivity [1/s]
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const scalar ki = Ai_*exp(-Ei_/specie::RR/T);
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// Thiele modulus []
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const scalar phi =
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max(0.5*d*sqrt(Sb_*rhop*Ag_*ki*ppO2/(De*rhoO2)), ROOTVSMALL);
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// Effectiveness factor []
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const scalar eta = max(3.0*sqr(phi)*(phi/tanh(phi) - 1.0), 0.0);
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// Chemical rate [kmol/m2/s]
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const scalar R = eta*d/6.0*rhop*Ag_*ki;
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// Particle surface area [m2]
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const scalar Ap = constant::mathematical::pi*sqr(d);
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// Change in C mass [kg]
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scalar dmC = Ap*rhoc*specie::RR*Tc*YO2/WO2_*D0*R/(D0 + R)*dt;
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// Limit mass transfer by availability of C
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dmC = min(mass*Ychar, dmC);
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// Molar consumption [kmol]
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const scalar dOmega = dmC/WC_;
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// Change in O2 mass [kg]
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const scalar dmO2 = dOmega*Sb_*WO2_;
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// Mass of newly created CO2 [kg]
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const scalar dmCO2 = dOmega*(WC_ + Sb_*WO2_);
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// Update local particle C mass
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dMassSolid[CsLocalId_] += dOmega*WC_;
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// Update carrier O2 and CO2 mass
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dMassSRCarrier[O2GlobalId_] -= dmO2;
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dMassSRCarrier[CO2GlobalId_] += dmCO2;
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const scalar HsC = thermo.solids().properties()[CsLocalId_].Hs(T);
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// carrier sensible enthalpy exchange handled via change in mass
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// Heat of reaction [J]
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return dmC*HsC - dmCO2*HcCO2_;
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}
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// ************************************************************************* //
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@ -0,0 +1,186 @@
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/*---------------------------------------------------------------------------*\
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========= |
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||||
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
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||||
\\ / O peration |
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||||
\\ / A nd | Copyright (C) 2013-2014 OpenCFD Ltd.
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\\/ M anipulation |
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||||
-------------------------------------------------------------------------------
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||||
License
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This file is part of OpenFOAM.
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OpenFOAM is free software: you can redistribute it and/or modify it
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||||
under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
|
||||
(at your option) any later version.
|
||||
|
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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.
|
||||
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||||
You should have received a copy of the GNU General Public License
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along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
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Class
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COxidationIntrinsicRate
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Description
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Intrinsic char surface reaction mndel
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C(s) + Sb*O2 -> CO2
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where Sb is the stoichiometry of the reaction
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\*---------------------------------------------------------------------------*/
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#ifndef COxidationIntrinsicRate_H
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#define COxidationIntrinsicRate_H
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#include "SurfaceReactionModel.H"
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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// Forward class declarations
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template<class CloudType>
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class COxidationIntrinsicRate;
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namespace Foam
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{
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/*---------------------------------------------------------------------------*\
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Class COxidationIntrinsicRate Declaration
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\*---------------------------------------------------------------------------*/
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template<class CloudType>
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class COxidationIntrinsicRate
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:
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public SurfaceReactionModel<CloudType>
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{
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// Private data
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// Model constants
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//- Stoichiometry of reaction []
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const scalar Sb_;
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//- Mass diffusion limited rate constant
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const scalar C1_;
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//- Mean pore radius [m]
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const scalar rMean_;
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//- Char porosity [] = 1 - rho_apparent/rho_true
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const scalar theta_;
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//- Pre-exponential factor
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const scalar Ai_;
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//- Activation energy
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const scalar Ei_;
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//- Char specific internal area [m2/kg]
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const scalar Ag_;
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//- Pore tortuosity []; default to sqrt(2)
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const scalar tau_;
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// Addressing
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//- Cs positions in global/local lists
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label CsLocalId_;
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//- O2 position in global list
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label O2GlobalId_;
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//- CO2 positions in global list
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label CO2GlobalId_;
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// Local copies of thermo properties
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//- Molecular weight of C [kg/kmol]
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scalar WC_;
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//- Molecular weight of O2 [kg/kmol]
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scalar WO2_;
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//- Formation enthalpy for CO2 [J/kg]
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scalar HcCO2_;
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public:
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//- Runtime type information
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TypeName("COxidationIntrinsicRate");
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// Constructors
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//- Construct from dictionary
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COxidationIntrinsicRate
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(
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const dictionary& dict,
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CloudType& owner
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);
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//- Construct copy
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COxidationIntrinsicRate
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(
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const COxidationIntrinsicRate<CloudType>& srm
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);
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//- Construct and return a clone
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virtual autoPtr<SurfaceReactionModel<CloudType> > clone() const
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{
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return autoPtr<SurfaceReactionModel<CloudType> >
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(
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new COxidationIntrinsicRate<CloudType>(*this)
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);
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}
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//- Destructor
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virtual ~COxidationIntrinsicRate();
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// Member Functions
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//- Update surface reactions
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virtual scalar calculate
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(
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const scalar dt,
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const label cellI,
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const scalar d,
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const scalar T,
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const scalar Tc,
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const scalar pc,
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const scalar rhoc,
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const scalar mass,
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const scalarField& YGas,
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const scalarField& YLiquid,
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const scalarField& YSolid,
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const scalarField& YMixture,
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const scalar N,
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scalarField& dMassGas,
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scalarField& dMassLiquid,
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scalarField& dMassSolid,
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scalarField& dMassSRCarrier
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) const;
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};
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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} // End namespace Foam
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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#ifdef NoRepository
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#include "COxidationIntrinsicRate.C"
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#endif
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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#endif
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// ************************************************************************* //
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Reference in New Issue
Block a user