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/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\/ M anipulation |
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License
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Class
Foam::combustionModels::FSD
Group
grpCombustionModels
Description
Flame Surface Dennsity (FDS) combustion model.
The fuel source term is given by mgft*pc*omegaFuelBar.
where:
mgft: filtered flame area.
pc: probability of the combustion 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 expential distribution.
The spacial 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 combustion 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 "singleStepCombustion.H"
#include "reactionRateFlameArea.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
namespace Foam
{
namespace combustionModels
{
/*---------------------------------------------------------------------------*\
Class FSD Declaration
\*---------------------------------------------------------------------------*/
template<class ReactionThermo, class ThermoType>
public singleStepCombustion <ReactionThermo, ThermoType>
{
// 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 oxidizer 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();
//- No copy construct
FSD(const FSD&) = delete;
//- No copy assignment
void operator=(const FSD&) = delete;
public:
//- Runtime type information
TypeName("FSD");
// Constructors
//- Construct from components
FSD
(
const word& modelType,
ReactionThermo& thermo,
const compressibleTurbulenceModel& turb,
const word& combustionProperties
//- Destructor
virtual ~FSD();
//- Correct combustion rate
virtual void correct();
//- Update properties
virtual bool read();
};
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
} // End namespace combustionModels
} // End namespace Foam
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
#ifdef NoRepository
#include "FSD.C"