XiFluid.H

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License
    This file is part of OpenFOAM.
 
    OpenFOAM is free software: you can redistribute it and/or modify it
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    the Free Software Foundation, either version 3 of the License, or
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    You should have received a copy of the GNU General Public License
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Class
    Foam::solvers::XiFluid
 
Description
    Solver module for compressible premixed/partially-premixed combustion with
    turbulence modelling.
 
    Combusting RANS code using the Weller b-Xi two-equation combustion model.
    Xi may be obtained by either the solution of the Xi transport equation or
    from an algebraic expression.
 
    Reference:
    \verbatim
        Weller, H. G. (1993).
        The development of a new flame area combustion model
        using conditional averaging.
        Thermo-fluids section report TF 9307.
    \endverbatim
 
    Both approaches are based on Gulder's flame speed correlation which has been
    shown to be appropriate by comparison with the results from the spectral
    model.
 
    Reference:
    \verbatim
        Weller, H. G., Marooney, C. J., & Gosman, A. D. (1991, January).
        A new spectral method for calculation of the time-varying area
        of a laminar flame in homogeneous turbulence.
        In Symposium (International) on Combustion
        (Vol. 23, No. 1, pp. 629-636). Elsevier.
    \endverbatim
 
    Strain effects are incorporated directly into the Xi equation
    but not in the algebraic approximation.  Further work need to be
    done on this issue, particularly regarding the enhanced removal rate
    caused by flame compression.  Analysis using results of the spectral
    model will be required.
 
    For cases involving very lean Propane flames or other flames which are
    very strain-sensitive, a transport equation for the laminar flame
    speed is present.  This equation is derived using heuristic arguments
    involving the strain time scale and the strain-rate at extinction.
    the transport velocity is the same as that for the Xi equation.
 
    Reference:
    \verbatim
        Weller, H. G., Tabor, G., Gosman, A. D., & Fureby, C. (1998, January).
        Application of a flame-wrinkling LES combustion model
        to a turbulent mixing layer.
        In Symposium (International) on combustion
        (Vol. 27, No. 1, pp. 899-907). Elsevier.
    \endverbatim
 
    For inhomogeneous mixtures, in addition to the regress variable \c b, it is
    necessary to solve for the mixture-fraction \c ft provided by the \c
    leanInhomogeneousMixture and also the fuel mass-fraction \c fu if there are
    rich regions in the mixture, provided by the \c inhomogeneousMixture.
    Details of the extension of the Weller b-Xi combustion model to non-premixed
    combustion can be found in the Technical Report TR/HGW/03.
 
    Reference:
    \verbatim
        Weller, H. G. (2002, August).
        The Application of the Weller Combustion Models to
        Non-Premixed Combustion.
        (Technical Report TR/HGW/03)
    \endverbatim
 
    For inhomogeneous mixtures with exhaust gas re-circulation it is necessary
    to additionally solve for the recirculated exhaust gas mass-fraction \c
    egr which is provided by the \c inhomogeneousEGRMixture mixture.
 
    Uses the flexible PIMPLE (PISO-SIMPLE) solution for time-resolved and
    pseudo-transient and steady simulations.
 
    Reference:
    \verbatim
        Greenshields, C. J., & Weller, H. G. (2022).
        Notes on Computational Fluid Dynamics: General Principles.
        CFD Direct Ltd.: Reading, UK.
    \endverbatim
 
    Optional fvModels and fvConstraints are provided to enhance the simulation
    in many ways including adding various sources, chemical reactions,
    combustion, Lagrangian particles, radiation, surface film etc. and
    constraining or limiting the solution.
 
SourceFiles
    XiFluid.C
 
See also
    Foam::solvers::fluidSolver
    Foam::solvers::isothermalFluid
 
\*---------------------------------------------------------------------------*/
 
#ifndef XiFluid_H
#define XiFluid_H
 
#include "isothermalFluid.H"
#include "psiuMulticomponentThermo.H"
#include "RASThermophysicalTransportModel.H"
#include "unityLewisEddyDiffusivity.H"
#include "SuModel.H"
#include "XiModel.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
namespace solvers
{
 
/*---------------------------------------------------------------------------*\
                          Class XiFluid Declaration
\*---------------------------------------------------------------------------*/
 
class XiFluid
:
    public isothermalFluid
{
 
protected:
 
    // Thermophysical properties
 
        psiuMulticomponentThermo& thermo_;
 
 
    // Composition
 
        //- Reference to the combustion regress variable
        volScalarField& b_;
 
        //- Set of fields used for the multivariate convection scheme
        multivariateSurfaceInterpolationScheme<scalar>::fieldTable fields;
 
 
    // Thermophysical transport
 
        turbulenceThermophysicalTransportModels::unityLewisEddyDiffusivity
        <
            RASThermophysicalTransportModel
            <
                ThermophysicalTransportModel
                <
                    compressibleMomentumTransportModel,
                    fluidThermo
                >
            >
        > thermophysicalTransport;
 
 
    // Reactions
 
        //- Dictionary of combustion model coefficients
        IOdictionary combustionProperties;
 
        //- Strained laminar flame-speed model
        autoPtr<SuModel> SuModel_;
 
        //- Flame wrinkling model
        autoPtr<XiModel> XiModel_;
 
 
    // Protected member functions
 
        //- Solve the ft equation for partially-premixed mixtures
        void ftSolve
        (
            const fv::convectionScheme<scalar>& mvConvection,
            const volScalarField& Db
        );
 
        //- Solve the fu equation for partially- and non- premixed mixtures
        void fuSolve
        (
            const fv::convectionScheme<scalar>& mvConvection,
            const volScalarField& Db,
            const volScalarField& bSource
        );
 
        //- Solve the egr mass-fraction equation
        //  for mixtures with exhaust gas recirculation
        void egrSolve
        (
            const fv::convectionScheme<scalar>& mvConvection,
            const volScalarField& Db
        );
 
        //- Apply the early kernel growth correction to the flame-wrinkling Xi
        //  to compensate for the inaccurate flame surface area estimate
        //  when the kernel is not fully-developed,
        //  i.e. does not have a completely burnt side
        tmp<volScalarField> XiCorr
        (
            const volScalarField& Xi,
            const surfaceScalarField& nf,
            const dimensionedScalar& dMgb
        ) const;
 
        //- Solve the Xi and regress variable equations
        void bSolve
        (
            const fv::convectionScheme<scalar>& mvConvection,
            const volScalarField& Db
        );
 
        //- Solve the unburnt energy equation
        void EauSolve
        (
            const fv::convectionScheme<scalar>& mvConvection,
            const volScalarField& Db
        );
 
        //- Solve the energy equation
        void EaSolve
        (
            const fv::convectionScheme<scalar>& mvConvection,
            const volScalarField& Db
        );
 
 
public:
 
        //- Reference to the fluid thermophysical properties
        const psiuMulticomponentThermo& thermo;
 
        //- Reference to the combustion regress variable
        //  obtained from the combustion mixture
        const volScalarField& b;
 
        //- Laminar flame speed
        const volScalarField& Su;
 
        //- Flame wrinkling
        const volScalarField& Xi;
 
 
    //- Runtime type information
    TypeName("XiFluid");
 
 
    // Constructors
 
        //- Construct from region mesh
        XiFluid(fvMesh& mesh);
 
        //- Disallow default bitwise copy construction
        XiFluid(const XiFluid&) = delete;
 
 
    //- Destructor
    virtual ~XiFluid();
 
 
    // Member Functions
 
        //- Predict thermophysical transport
        virtual void thermophysicalTransportPredictor();
 
        //- Construct and solve the energy equation,
        //  convert to temperature
        //  and update thermophysical and transport properties
        virtual void thermophysicalPredictor();
 
        //- Correct the thermophysical transport
        virtual void thermophysicalTransportCorrector();
 
        //- Reset b-Xi and thermodynamics to the unburnt state
        //  for multi-cycle simulations
        virtual void reset();
 
 
    // Member Operators
 
        //- Disallow default bitwise assignment
        void operator=(const XiFluid&) = delete;
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace solvers
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //