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========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration | Website: https://openfoam.org
\\ / A nd | Copyright (C) 2011-2026 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
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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
Foam::reactionModels::FSD
Description
Flame Surface Density (FDS) reaction model.
The fuel source term is given by mgft*pc*omegaFuelBar.
where:
mgft: filtered flame area.
pc: probability of the reaction progress.
omegaFuelBar: filtered consumption speed per unit of flame area.
pc is considered from the IFC solution.
omegaFuelBar is calculated solving a relaxation equation which tends to
omegaEq. This omegaEq is obtained from the flamelet solution for
different strain rates and fit using a exponential distribution.
The spatial distribution of the consumption speed (omega) is obtained also
from a strained flamelet solution and it is assumed to have a gaussian
distribution.
If the grid resolution is not enough to resolve the flame, the consumption
speed distribution is linearly thickened conserving the overall heat
release.
If the turbulent fluctuation of the mixture fraction at the sub-grid level
is large (>1e-04) then a beta pdf is used for filtering.
At the moment the flame area reaction model is only fit to work in a LES
frame work. In RAS the subgrid fluctuation has to be solved by an extra
transport equation.
SourceFiles
FSD.C
\*---------------------------------------------------------------------------*/
#ifndef FSD_H
#define FSD_H
#include "singleStepReaction.H"
#include "reactionRateFlameArea.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
namespace Foam
{
namespace reactionModels
{
/*---------------------------------------------------------------------------*\
Class FSD Declaration
\*---------------------------------------------------------------------------*/
class FSD
:
public singleStepReaction
{
// Private Data
//- Auto pointer to consumption speed per unit of flame area model
autoPtr<reactionRateFlameArea> reactionRateFlameArea_;
//- Mixture fraction
volScalarField ft_;
//- Fuel mass concentration on the fuel stream
dimensionedScalar YFuelFuelStream_;
//- Oxygen mass concentration on the oxidiser stream
dimensionedScalar YO2OxiStream_;
//- Similarity constant for the sub-grid ft fluctuations
scalar Cv_;
//- Model constant
scalar C_;
//- Lower flammability limit
scalar ftMin_;
//- Upper flammability limit
scalar ftMax_;
//- Dimension of the ft space. Used to integrate the beta-pdf
scalar ftDim_;
//- Minimum mixture fraction variance to calculate pdf
scalar ftVarMin_;
// Private Member Functions
//- Calculate the normalised fuel source term
void calculateSourceNorm();
public:
//- Runtime type information
TypeName("FSD");
// Constructors
//- Construct from components
FSD
(
const word& modelType,
const fluidMulticomponentThermo& thermo,
const compressibleMomentumTransportModel& turb,
const word& reactionProperties
);
//- Disallow default bitwise copy construction
FSD(const FSD&) = delete;
//- Destructor
virtual ~FSD();
// Member Functions
//- Correct reaction rate
virtual void correct();
//- Update properties
virtual bool read();
// Member Operators
//- Disallow default bitwise assignment
void operator=(const FSD&) = delete;
};
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
} // End namespace reactionModels
} // End namespace Foam
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
#endif
// ************************************************************************* //
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