254 lines
6.9 KiB
C
254 lines
6.9 KiB
C
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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 held by original author
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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 the
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Free Software Foundation; either version 2 of the License, or (at your
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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, write to the Free Software Foundation,
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Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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Class
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Foam::XiModel
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Description
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Base-class for all Xi models used by the b-Xi combustion model.
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See Technical Report SH/RE/01R for details on the PDR modelling.
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Xi is given through an algebraic expression (\link algebraic.H \endlink),
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by solving a transport equation (\link transport.H \endlink) or a
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fixed value (\link fixed.H \endlink).
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See report TR/HGW/10 for details on the Weller two equations model.
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In the algebraic and transport methods \f$\Xi_{eq}\f$ is calculated in
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similar way. In the algebraic approach, \f$\Xi_{eq}\f$ is the value used in
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the \f$ b \f$ transport equation.
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\f$\Xi_{eq}\f$ is calculated as follows:
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\f$\Xi_{eq} = 1 + (1 + 2\Xi_{coeff}(0.5 - \dwea{b}))(\Xi^* - 1)\f$
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where:
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\f$ \dwea{b} \f$ is the regress variable.
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\f$ \Xi_{coeff} \f$ is a model constant.
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\f$ \Xi^* \f$ is the total equilibrium wrinkling combining the effects
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of the flame inestability and turbulence interaction and is given by
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\f[
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\Xi^* = \frac {R}{R - G_\eta - G_{in}}
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\f]
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where:
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\f$ G_\eta \f$ is the generation rate of wrinkling due to turbulence
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interaction.
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\f$ G_{in} = \kappa \rho_{u}/\rho_{b} \f$ is the generation
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rate due to the flame inestability.
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By adding the removal rates of the two effects:
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\f[
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R = G_\eta \frac{\Xi_{\eta_{eq}}}{\Xi_{\eta_{eq}} - 1}
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+ G_{in} \frac{\Xi_{{in}_{eq}}}{\Xi_{{in}_{eq}} - 1}
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\f]
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where:
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\f$ R \f$ is the total removal.
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\f$ G_\eta \f$ is a model constant.
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\f$ \Xi_{\eta_{eq}} \f$ is the flame wrinkling due to turbulence.
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\f$ \Xi_{{in}_{eq}} \f$ is the equilibrium level of the flame wrinkling
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generated by inestability. It is a constant (default 2.5).
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SourceFiles
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XiModel.C
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\*---------------------------------------------------------------------------*/
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#ifndef XiModel_H
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#define XiModel_H
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#include "IOdictionary.H"
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#include "hhuCombustionThermo.H"
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#include "RASModel.H"
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#include "multivariateSurfaceInterpolationScheme.H"
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#include "runTimeSelectionTables.H"
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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namespace Foam
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{
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/*---------------------------------------------------------------------------*\
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Class XiModel Declaration
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\*---------------------------------------------------------------------------*/
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class XiModel
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{
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protected:
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// Protected data
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dictionary XiModelCoeffs_;
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const hhuCombustionThermo& thermo_;
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const compressible::RASModel& turbulence_;
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const volScalarField& Su_;
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const volScalarField& rho_;
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const volScalarField& b_;
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const surfaceScalarField& phi_;
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//- Flame wrinking field
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volScalarField Xi_;
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private:
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// Private Member Functions
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//- Disallow copy construct
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XiModel(const XiModel&);
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//- Disallow default bitwise assignment
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void operator=(const XiModel&);
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public:
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//- Runtime type information
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TypeName("XiModel");
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// Declare run-time constructor selection table
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declareRunTimeSelectionTable
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(
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autoPtr,
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XiModel,
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dictionary,
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(
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const dictionary& XiProperties,
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const hhuCombustionThermo& thermo,
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const compressible::RASModel& turbulence,
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const volScalarField& Su,
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const volScalarField& rho,
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const volScalarField& b,
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const surfaceScalarField& phi
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),
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(
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XiProperties,
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thermo,
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turbulence,
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Su,
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rho,
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b,
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phi
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)
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);
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// Selectors
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//- Return a reference to the selected Xi model
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static autoPtr<XiModel> New
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(
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const dictionary& XiProperties,
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const hhuCombustionThermo& thermo,
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const compressible::RASModel& turbulence,
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const volScalarField& Su,
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const volScalarField& rho,
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const volScalarField& b,
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const surfaceScalarField& phi
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);
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// Constructors
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//- Construct from components
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XiModel
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(
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const dictionary& XiProperties,
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const hhuCombustionThermo& thermo,
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const compressible::RASModel& turbulence,
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const volScalarField& Su,
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const volScalarField& rho,
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const volScalarField& b,
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const surfaceScalarField& phi
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);
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// Destructor
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virtual ~XiModel();
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// Member Functions
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//- Return the flame-wrinking Xi
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virtual const volScalarField& Xi() const
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{
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return Xi_;
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}
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//- Return the flame diffusivity
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virtual tmp<volScalarField> Db() const
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{
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return turbulence_.muEff();
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}
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//- Add Xi to the multivariateSurfaceInterpolationScheme table
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// if required
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virtual void addXi
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(
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multivariateSurfaceInterpolationScheme<scalar>::fieldTable&
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)
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{}
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//- Correct the flame-wrinking Xi
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virtual void correct() = 0;
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//- Correct the flame-wrinking Xi using the given convection scheme
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virtual void correct(const fv::convectionScheme<scalar>&)
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{
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correct();
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}
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//- Update properties from given dictionary
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virtual bool read(const dictionary& XiProperties) = 0;
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};
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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} // End namespace Foam
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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#endif
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// ************************************************************************* //
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