All models that require templating on the thermodynamic model, including
the thermodynamic models themselves, are now instantiated using a
centralised set of variadic macros. Seven macros exist to instantiate
models for different classes of thermodynamics model. These are:
forGases: All model combinations valid for gases
forCommonGases: The most commonly used gas models
forAbsoluteGases: A limited selection of gas models with absolute
forms of energy, for use with Xi-combustion models
forLiquids: All model combinations valid for liquids
forCommonLiquids: The most commonly used liquid models
forPolynomials: Model combinations with properties fitted to
polynomials
forSolids: All model combinations valid for solids
All the *ThermoPhysics typedefs have been removed, as this system was
fundamentally not extensible. The enormous lists of thermodynamic
instantiations that existed for reaction thermos, chemistry models,
tabulation methods, etc..., were extremely difficult to read and reason
about what combinations are valid under what circumstances. This change
centralises those decisions, makes them concise and readable, and makes
them consistent across the entire codebase.
Soot model selection has now been brought up to date in line with
chemistry, combustion, and others. The angle-bracketed part of the name
is no longer necessary; this information is determined directly from the
existing thermo model. So, now to select a mixture-fraction soot model,
the entry is simply:
sootModel mixtureFraction;
Rather than:
sootModel mixtureFraction<rhoReactionThermo,gasHThermoPhysics>;
The only place in which *ThermoPhysics typedefs are still required in
the selection name is in the thermalBaffle1D boundary condition. Here
there is no thermo model from which to determine a name. This eventually
needs resolving either by adding a selection mechanism similar to that
of the thermo packages themselves, or by removing this boundary
condition in favour of the (non-1D) thermal baffle boundary condition
and region model.
providing the shear-stress term in the momentum equation for incompressible and
compressible Newtonian, non-Newtonian and visco-elastic laminar flow as well as
Reynolds averaged and large-eddy simulation of turbulent flow.
The general deviatoric shear-stress term provided by the MomentumTransportModels
library is named divDevTau for compressible flow and divDevSigma (sigma =
tau/rho) for incompressible flow, the spherical part of the shear-stress is
assumed to be either included in the pressure or handled separately. The
corresponding stress function sigma is also provided which in the case of
Reynolds stress closure returns the effective Reynolds stress (including the
laminar contribution) or for other Reynolds averaged or large-eddy turbulence
closures returns the modelled Reynolds stress or sub-grid stress respectively.
For visco-elastic flow the sigma function returns the effective total stress
including the visco-elastic and Newtonian contributions.
For thermal flow the heat-flux generated by thermal diffusion is now handled by
the separate ThermophysicalTransportModels library allowing independent run-time
selection of the heat-flux model.
During the development of the MomentumTransportModels library significant effort
has been put into rationalising the components and supporting libraries,
removing redundant code, updating names to provide a more logical, consistent
and extensible interface and aid further development and maintenance. All
solvers and tutorials have been updated correspondingly and backward
compatibility of the input dictionaries provided.
Henry G. Weller
CFD Direct Ltd.
Following the generalisation of the TurbulenceModels library to support
non-Newtonian laminar flow including visco-elasticity and extensible to other
form of non-Newtonian behaviour the name TurbulenceModels is misleading and does
not properly represent how general the OpenFOAM solvers now are. The
TurbulenceModels now provides an interface to momentum transport modelling in
general and the plan is to rename it MomentumTransportModels and in preparation
for this the turbulenceProperties dictionary has been renamed momentumTransport
to properly reflect its new more general purpose.
The old turbulenceProperties name is supported for backward-compatibility.
The chemistryModel and combustionModel do not change the thermodynamics directly
and should not require non-const access to it. In order to change the
thermodynamics model argument and stored references to const the specie "active"
flags in TDAC have been changed to mutable as this is not a direct change in the
thermodynamic state but a set of switches which allow the state to change
differently during the next thermodynamics update.
Now that the reaction system is separated from the mixture thermodynamics it is
possible to rationalise singleStepCombustion so that it instantiates a single
reaction as it should. This simplifies the code, maintenance and the user
interface not that the combustionProperties file contains a single reaction
rather than a list.
This allows much greater flexibility in the instantiation of reaction system
which may in general depend on fields other than the thermodynamic state. This
also simplifies mixture thermodynamics removing the need for the reactingMixture
and the instantiation of all the thermodynamic package combinations depending on
it.
Currently these deleted function declarations are still in the private section
of the class declarations but will be moved by hand to the public section over
time as this is too complex to automate reliably.
The radiation modelling library has been moved out of
thermophysicalProperties into the top-level source directory. Radiation
is a process, not a property, and belongs alongside turbulence,
combustion, etc...
The namespaces used within the radiation library have been made
consistent with the rest of the code. Selectable sub-models are in
namespaces named after their base classes. Some models have been
renamed remove the base type from the suffix, as this is unnecessary.
These renames are:
Old name: New name:
binaryAbsorptionEmission binary
cloudAbsorptionEmission cloud
constantAbsorptionEmission constant
greyMeanAbsorptionEmission greyMean/greyMeanCombustion
greyMeanSolidAbsorptionEmission greyMeanSolid
wideBandAbsorptionEmission wideBand/wideBandCombustion
cloudScatter cloud
constantScatter constant
mixtureFractionSoot mixtureFraction
Some absorption-emission models have been split into versions which do
and don't use the heat release rate. The version that does has been
given the post-fix "Combustion" and has been moved into the
combustionModels library. This removes the dependence on a registered
Qdot field, and makes the models compatible with the recent removal of
that field from the combustion solvers.
The Qdot field has been removed from all reacting solvers, in favour of
computing on the fly whenever it is needed. It can still be generated
for post-processing purposes by means of the Qdot function object. This
change reduces code duplication and storage for all modified solvers.
The Qdot function object has been applied to a number of tutorials in
order to retain the existing output.
A fix to Qdot has also been applied for multi-phase cases.
This function object writes out the heat release rate field for a
combustion model. This is useful for solvers where combustion is
optional, and which do not therefore write out the heat release rate by
default; e.g., chtMultiRegionFoam and reactingTwoPhaseEulerFoam.
Registration occurs when the temporary field is transferred to a non-temporary
field via a constructor or if explicitly transferred to the database via the
regIOobject "store" methods.
In early versions of OpenFOAM the scalar limits were simple macro replacements and the
names were capitalized to indicate this. The scalar limits are now static
constants which is a huge improvement on the use of macros and for consistency
the names have been changed to camel-case to indicate this and improve
readability of the code:
GREAT -> great
ROOTGREAT -> rootGreat
VGREAT -> vGreat
ROOTVGREAT -> rootVGreat
SMALL -> small
ROOTSMALL -> rootSmall
VSMALL -> vSmall
ROOTVSMALL -> rootVSmall
The original capitalized are still currently supported but their use is
deprecated.
When the constant/combustionProperties dictionary is missing, the solver
will now default to the "none" model. This is consistent with how
radiation models are selected.
Wrapped combustion model make macros in the Foam namespace and removed
combustion model namespace from the base classes. This fixes a namespace
specialisation bug in gcc 4.8. It is also somewhat less verbose in the
solvers.
This resolves bug report https://bugs.openfoam.org/view.php?id=2787
The combustion and chemistry model selection has been simplified so
that the user does not have to specify the form of the thermodynamics.
Examples of new combustion and chemistry entries are as follows:
In constant/combustionProperties:
combustionModel PaSR;
combustionModel FSD;
In constant/chemistryProperties:
chemistryType
{
solver ode;
method TDAC;
}
All the angle bracket parts of the model names (e.g.,
<psiThermoCombustion,gasHThermoPhysics>) have been removed as well as
the chemistryThermo entry.
The changes are mostly backward compatible. Only support for the
angle bracket form of chemistry solver names has been removed. Warnings
will print if some of the old entries are used, as the parts relating to
thermodynamics are now ignored.
The combustion and chemistry models no longer select and own the
thermodynamic model; they hold a reference instead. The construction of
the combustion and chemistry models has been changed to require a
reference to the thermodyanmics, rather than the mesh and a phase name.
At the solver-level the thermo, turbulence and combustion models are now
selected in sequence. The cyclic dependency between the three models has
been resolved, and the raw-pointer based post-construction step for the
combustion model has been removed.
The old solver-level construction sequence (typically in createFields.H)
was as follows:
autoPtr<combustionModels::psiCombustionModel> combustion
(
combustionModels::psiCombustionModel::New(mesh)
);
psiReactionThermo& thermo = combustion->thermo();
// Create rho, U, phi, etc...
autoPtr<compressible::turbulenceModel> turbulence
(
compressible::turbulenceModel::New(rho, U, phi, thermo)
);
combustion->setTurbulence(*turbulence);
The new sequence is:
autoPtr<psiReactionThermo> thermo(psiReactionThermo::New(mesh));
// Create rho, U, phi, etc...
autoPtr<compressible::turbulenceModel> turbulence
(
compressible::turbulenceModel::New(rho, U, phi, *thermo)
);
autoPtr<combustionModels::psiCombustionModel> combustion
(
combustionModels::psiCombustionModel::New(*thermo, *turbulence)
);
"pos" now returns 1 if the argument is greater than 0, otherwise it returns 0.
This is consistent with the common mathematical definition of the "pos" function:
https://en.wikipedia.org/wiki/Sign_(mathematics)
However the previous implementation in which 1 was also returned for a 0
argument is useful in many situations so the "pos0" has been added which returns
1 if the argument is greater or equal to 0. Additionally the "neg0" has been
added which returns 1 if if the argument is less than or equal to 0.
except turbulence and lagrangian which will also be updated shortly.
For example in the nonNewtonianIcoFoam offsetCylinder tutorial the viscosity
model coefficients may be specified in the corresponding "<type>Coeffs"
sub-dictionary:
transportModel CrossPowerLaw;
CrossPowerLawCoeffs
{
nu0 [0 2 -1 0 0 0 0] 0.01;
nuInf [0 2 -1 0 0 0 0] 10;
m [0 0 1 0 0 0 0] 0.4;
n [0 0 0 0 0 0 0] 3;
}
BirdCarreauCoeffs
{
nu0 [0 2 -1 0 0 0 0] 1e-06;
nuInf [0 2 -1 0 0 0 0] 1e-06;
k [0 0 1 0 0 0 0] 0;
n [0 0 0 0 0 0 0] 1;
}
which allows a quick change between models, or using the simpler
transportModel CrossPowerLaw;
nu0 [0 2 -1 0 0 0 0] 0.01;
nuInf [0 2 -1 0 0 0 0] 10;
m [0 0 1 0 0 0 0] 0.4;
n [0 0 0 0 0 0 0] 3;
if quick switching between models is not required.
To support this more convenient parameter specification the inconsistent
specification of seedSampleSet in the streamLine and wallBoundedStreamLine
functionObjects had to be corrected from
// Seeding method.
seedSampleSet uniform; //cloud; //triSurfaceMeshPointSet;
uniformCoeffs
{
type uniform;
axis x; //distance;
// Note: tracks slightly offset so as not to be on a face
start (-1.001 -0.05 0.0011);
end (-1.001 -0.05 1.0011);
nPoints 20;
}
to the simpler
// Seeding method.
seedSampleSet
{
type uniform;
axis x; //distance;
// Note: tracks slightly offset so as not to be on a face
start (-1.001 -0.05 0.0011);
end (-1.001 -0.05 1.0011);
nPoints 20;
}
which also support the "<type>Coeffs" form
// Seeding method.
seedSampleSet
{
type uniform;
uniformCoeffs
{
axis x; //distance;
// Note: tracks slightly offset so as not to be on a face
start (-1.001 -0.05 0.0011);
end (-1.001 -0.05 1.0011);
nPoints 20;
}
}
including support for TDAC and ISAT for efficient chemistry calculation.
Description
Eddy Dissipation Concept (EDC) turbulent combustion model.
This model considers that the reaction occurs in the regions of the flow
where the dissipation of turbulence kinetic energy takes place (fine
structures). The mass fraction of the fine structures and the mean residence
time are provided by an energy cascade model.
There are many versions and developments of the EDC model, 4 of which are
currently supported in this implementation: v1981, v1996, v2005 and
v2016. The model variant is selected using the optional \c version entry in
the \c EDCCoeffs dictionary, \eg
\verbatim
EDCCoeffs
{
version v2016;
}
\endverbatim
The default version is \c v2015 if the \c version entry is not specified.
Model versions and references:
\verbatim
Version v2005:
Cgamma = 2.1377
Ctau = 0.4083
kappa = gammaL^exp1 / (1 - gammaL^exp2),
where exp1 = 2, and exp2 = 2.
Magnussen, B. F. (2005, June).
The Eddy Dissipation Concept -
A Bridge Between Science and Technology.
In ECCOMAS thematic conference on computational combustion
(pp. 21-24).
Version v1981:
Changes coefficients exp1 = 3 and exp2 = 3
Magnussen, B. (1981, January).
On the structure of turbulence and a generalized
eddy dissipation concept for chemical reaction in turbulent flow.
In 19th Aerospace Sciences Meeting (p. 42).
Version v1996:
Changes coefficients exp1 = 2 and exp2 = 3
Gran, I. R., & Magnussen, B. F. (1996).
A numerical study of a bluff-body stabilized diffusion flame.
Part 2. Influence of combustion modeling and finite-rate chemistry.
Combustion Science and Technology, 119(1-6), 191-217.
Version v2016:
Use local constants computed from the turbulent Da and Re numbers.
Parente, A., Malik, M. R., Contino, F., Cuoci, A., & Dally, B. B.
(2016).
Extension of the Eddy Dissipation Concept for
turbulence/chemistry interactions to MILD combustion.
Fuel, 163, 98-111.
\endverbatim
Tutorials cases provided: reactingFoam/RAS/DLR_A_LTS, reactingFoam/RAS/SandiaD_LTS.
This codes was developed and contributed by
Zhiyi Li
Alessandro Parente
Francesco Contino
from BURN Research Group
and updated and tested for release by
Henry G. Weller
CFD Direct Ltd.
Combined 'dQ()' and 'Sh()' into 'Qdot()' which returns the heat-release rate in
the normal units [kg/m/s3] and used as the heat release rate source term in
the energy equations, to set the field 'Qdot' in several combustion solvers
and for the evaluation of the local time-step when running LTS.
to avoid duplicate instantiation of the thermodynamics package.
The 'zoneCombustion' model is now selected in constant/combustionProperties by
either
combustionModel zoneCombustion<psiCombustionModel>;
or
combustionModel zoneCombustion<rhoCombustionModel>;
as appropriate.
Resolves bug-report http://bugs.openfoam.org/view.php?id=2354
in which the reactions are enabled only in the specified list of
cellZones. e.g. in constant/combustionProperties
combustionModel zoneCombustion<psiChemistryCombustion>;
active true;
zoneCombustionCoeffs
{
zones (catalyst);
}
and in constant/zoneCombustionProperties
combustionModel laminar<psiChemistryCombustion>;
active true;
laminarCoeffs
{}
In order to simplify expressions involving dimensioned internal field it
is preferable to use a simpler access convention. Given that
GeometricField is derived from DimensionedField it is simply a matter of
de-referencing this underlying type unlike the boundary field which is
peripheral information. For consistency with the new convention in
"tmp" "dimensionedInteralFieldRef()" has been renamed "ref()".
When the GeometricBoundaryField template class was originally written it
was a separate class in the Foam namespace rather than a sub-class of
GeometricField as it is now. Without loss of clarity and simplifying
code which access the boundary field of GeometricFields it is better
that GeometricBoundaryField be renamed Boundary for consistency with the
new naming convention for the type of the dimensioned internal field:
Internal, see commit a25a449c9e
This is a very simple text substitution change which can be applied to
any code which compiles with the OpenFOAM-dev libraries.
Given that the type of the dimensioned internal field is encapsulated in
the GeometricField class the name need not include "Field"; the type
name is "Internal" so
volScalarField::DimensionedInternalField -> volScalarField::Internal
In addition to the ".dimensionedInternalField()" access function the
simpler "()" de-reference operator is also provided to greatly simplify
FV equation source term expressions which need not evaluate boundary
conditions. To demonstrate this kEpsilon.C has been updated to use
dimensioned internal field expressions in the k and epsilon equation
source terms.
