Files
openfoam/applications/solvers/multiphase/twoPhaseEulerFoam/twoPhaseSystem/twoPhaseSystem.H
Henry fc6b44ee3c twoPhaseEulerFoam: Added experimental face-based momentum equation formulation
This formulation provides C-grid like pressure-flux staggering on an
unstructured mesh which is hugely beneficial for Euler-Euler multiphase
equations as it allows for all forces to be treated in a consistent
manner on the cell-faces which provides better balance, stability and
accuracy.  However, to achieve face-force consistency the momentum
transport terms must be interpolated to the faces reducing accuracy of
this part of the system but this is offset by the increase in accuracy
of the force-balance.

Currently it is not clear if this face-based momentum equation
formulation is preferable for all Euler-Euler simulations so I have
included it on a switch to allow evaluation and comparison with the
previous cell-based formulation.  To try the new algorithm simply switch
it on, e.g.:

PIMPLE
{
    nOuterCorrectors 3;
    nCorrectors      1;
    nNonOrthogonalCorrectors 0;
    faceMomentum     yes;
}

It is proving particularly good for bubbly flows, eliminating the
staggering patterns often seen in the air velocity field with the
previous algorithm, removing other spurious numerical artifacts in the
velocity fields and improving stability and allowing larger time-steps
For particle-gas flows the advantage is noticeable but not nearly as
pronounced as in the bubbly flow cases.

Please test the new algorithm on your cases and provide feedback.

Henry G. Weller
CFD Direct
2015-04-27 21:33:58 +01:00

246 lines
7.0 KiB
C++

/*---------------------------------------------------------------------------*\
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\\ / O peration |
\\ / A nd | Copyright (C) 2013-2015 OpenFOAM Foundation
\\/ M anipulation |
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Class
Foam::twoPhaseSystem
Description
SourceFiles
twoPhaseSystem.C
\*---------------------------------------------------------------------------*/
#ifndef twoPhaseSystem_H
#define twoPhaseSystem_H
#include "IOdictionary.H"
#include "phaseModel.H"
#include "phasePair.H"
#include "orderedPhasePair.H"
#include "volFields.H"
#include "surfaceFields.H"
#include "dragModel.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
namespace Foam
{
class virtualMassModel;
class heatTransferModel;
class liftModel;
class wallLubricationModel;
class turbulentDispersionModel;
class blendingMethod;
template <class modelType> class BlendedInterfacialModel;
/*---------------------------------------------------------------------------*\
Class twoPhaseSystem Declaration
\*---------------------------------------------------------------------------*/
class twoPhaseSystem
:
public IOdictionary
{
// Private data
//- Reference to the mesh
const fvMesh& mesh_;
//- Phase model 1
phaseModel phase1_;
//- Phase model 2
phaseModel phase2_;
//- Total volumetric flux
surfaceScalarField phi_;
//- Dilatation term
volScalarField dgdt_;
//- Unordered phase pair
autoPtr<phasePair> pair_;
//- Phase pair for phase 1 dispersed in phase 2
autoPtr<orderedPhasePair> pair1In2_;
//- Phase pair for phase 2 dispersed in phase 1
autoPtr<orderedPhasePair> pair2In1_;
//- Blending methods
HashTable<autoPtr<blendingMethod>, word, word::hash> blendingMethods_;
//- Drag model
autoPtr<BlendedInterfacialModel<dragModel> > drag_;
//- Virtual mass model
autoPtr<BlendedInterfacialModel<virtualMassModel> > virtualMass_;
//- Heat transfer model
autoPtr<BlendedInterfacialModel<heatTransferModel> > heatTransfer_;
//- Lift model
autoPtr<BlendedInterfacialModel<liftModel> > lift_;
//- Wall lubrication model
autoPtr<BlendedInterfacialModel<wallLubricationModel> >
wallLubrication_;
//- Wall lubrication model
autoPtr<BlendedInterfacialModel<turbulentDispersionModel> >
turbulentDispersion_;
//-
static dimensionedScalar zeroResidualAlpha_;
// Private member functions
//- Return the mixture flux
tmp<surfaceScalarField> calcPhi() const;
public:
// Constructors
//- Construct from fvMesh
twoPhaseSystem(const fvMesh&, const dimensionedVector& g);
//- Destructor
virtual ~twoPhaseSystem();
// Member Functions
//- Return the mixture density
tmp<volScalarField> rho() const;
//- Return the mixture velocity
tmp<volVectorField> U() const;
//- Return the drag coefficient
tmp<volScalarField> Kd() const;
//- Return the face drag coefficient
tmp<surfaceScalarField> Kdf() const;
//- Return the virtual mass coefficient
tmp<volScalarField> Vm() const;
//- Return the face virtual mass coefficient
tmp<surfaceScalarField> Vmf() const;
//- Return the heat transfer coefficient
tmp<volScalarField> Kh() const;
//- Return the combined force (lift + wall-lubrication)
tmp<volVectorField> F() const;
//- Return the combined face-force (lift + wall-lubrication)
tmp<surfaceScalarField> Ff() const;
//- Return the turbulent diffusivity
// Multiplies the phase-fraction gradient
tmp<volScalarField> D() const;
//- Solve for the two-phase-fractions
void solve();
//- Correct two-phase properties other than turbulence
void correct();
//- Correct two-phase turbulence
void correctTurbulence();
//- Read base phaseProperties dictionary
bool read();
// Access
//- Return the residual phase-fraction for given phase
// Used to stabilize the phase momentum as the phase-fraction -> 0
const dimensionedScalar& residualAlpha
(
const phaseModel& phase
) const;
//- Return the drag model for the given phase
const dragModel& drag(const phaseModel& phase) const;
//- Return the virtual mass model for the given phase
const virtualMassModel& virtualMass(const phaseModel& phase) const;
//- Return the surface tension coefficient
const dimensionedScalar& sigma() const;
//- Return the mesh
inline const fvMesh& mesh() const;
//- Return phase model 1
inline const phaseModel& phase1() const;
//- Return non-const access to phase model 1
inline phaseModel& phase1();
//- Return phase model 2
inline const phaseModel& phase2() const;
//- Return non-const access to phase model 2
inline phaseModel& phase2();
//- Return the phase not given as an argument
inline const phaseModel& otherPhase(const phaseModel& phase) const;
//- Return the mixture flux
inline const surfaceScalarField& phi() const;
//- Return non-const access to the the mixture flux
inline surfaceScalarField& phi();
//- Return the dilatation term
inline const volScalarField& dgdt() const;
//- Return non-const access to the dilatation parameter
inline volScalarField& dgdt();
};
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
} // End namespace Foam
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
#include "twoPhaseSystemI.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
#endif
// ************************************************************************* //