An additional layer has been added into the phase system hierarchy which
facilitates the application of phase transfer modelling. These are
models which exchange mass between phases without the thermal coupling
that would be required to represent phase change. They can be thought of
as representation changes; e.g., between two phases representing
different droplet sizes of the same physical fluid.
To facilitate this, the heat transfer phase systems have been modified
and renamed and now both support mass transfer. The two sided version
is only required for derivations which support phase change.
The following changes to case settings have been made:
- The simplest instantiated phase systems have been renamed to
basicTwoPhaseSystem and basicMultiphaseSystem. The
heatAndMomentumTransfer*System entries in constant/phaseProperties files
will need updating accordingly.
- A phaseTransfer sub-model entry will be required in the
constant/phaseProperties file. This can be an empty list.
- The massTransfer switch in thermal phase change cases has been renamed
phaseTransfer, so as not to be confused with the mass transfer models
used by interface composition cases.
This work was supported by Georg Skillas and Zhen Li, at Evonik
Also added tutorial case demonstrating usage. Note that the new drag
models are symmetric and should be used without any blending.
This work was supported by Georg Skillas and Zhen Li, at Evonik
Sub-model blending should be set such that the sum of all the blending
coefficients equals one. If there are three models specified for a phase
pair (e.g., (air in water), (water in air) and (air and water)), then
the sum-to-one constraint is guaranteed by the blending functions.
Frequently, however, the symmetric model ((air and water) in this
example) is omitted. In that case, the blending coefficients should be
selected so that the sum of just the two non-symmetric coefficients
equal one.
In the case of linear blending, this means setting the minimum partially
continuous alpha to one-minus the fully continuous value of the opposite
phase. For example:
blending
{
default
{
type linear;
minFullyContinuousAlpha.air 0.7;
minPartlyContinuousAlpha.air 0.3;
minFullyContinuousAlpha.water 0.7;
minPartlyContinuousAlpha.water 0.3;
}
}
The reactingTwoPhaseEulerFoam and reactingMultiPhaseEulerFoam tutorials
have been modified to adhere to this principle.
Two new phase models have been added as selectable options for
reactingMultiphaseEulerFoam; pureStationaryPhaseModel and
pureStationaryIsothermalPhaseModel. These phases do not store a
velocity and their phase fractions remain constant throughout the
simulation. They are intended for use in modelling static particle beds
and other forms of porous media by means of the existing Euler-Euler
transfer models (drag, heat transfer, etc...).
Note that this functionality has not been extended to
reactingTwoPhaseEulerFoam, or the non-reacting *EulerFoam solvers.
Additional maintenance work has been carried out on the phase model
and phase system structure. The system can now loop over subsets of
phases with specific functionality (moving, multi-component, etc...) in
order to avoid testing for the existence of equations or variables in
the top level solver. The mass transfer handling and it's effect on
per-phase source terms has been refactored to reduce duplication. Const
and non-const access to phase properties has been formalised by renaming
non-const accessors with a "Ref" suffix, which is consistent with other
recent developments to classes including tmp and GeometricField, among
others. More sub-modelling details have been made private in order to
reduce the size of interfaces and improve abstraction.
This work was supported by Zhen Li, at Evonik
The initial set of cases in the test directory are aimed at testing the
reactingEulerFoam populationBalance functionality.
Patch contributed by Institute of Fluid Dynamics, Helmholtz-Zentrum
Dresden - Rossendorf (HZDR) and VTT Technical Research Centre of Finland Ltd.
Integrated with the "tutorials" functionality by CFD Direct Ltd.
This change means that getApplication still works if we have a
controlDict.orig, rather than a controlDict. This allows us to simplify
the scripting of tutorials in which the controlDict is modified.
Some tutorials have had Allrun scripts added in order to run setFields,
which was previously omitted. Others have had nonuniform field files in
the 0 directory replaced by uniform files with .orig extensions.
Now if a <field> file does not exist first the compressed <field>.gz file is
searched for and if that also does not exist the <field>.orig file is searched
for.
This simplifies case setup and run scripts as now setField for example can read
the <field>.orig file directly and generate the <field> file from it which is
then read by the solver. Additionally the cleanCase function used by
foamCleanCase and the Allclean scripts automatically removed <field> files if
there is a corresponding <field>.orig file. So now there is no need for the
Allrun scripts to copy <field>.orig files into <field> or for the Allclean
scripts to explicitly remove them.
Introduced thermalPhaseChangePopulationBalanceTwo- and MultiphaseSystem as
user-selectable phaseSystems which are the first to actually use multiple mass
transfer mechanisms enabled by
commit d3a237f560.
The functionality is demonstrated using the reactingTwoPhaseEulerFoam
wallBoilingPolydisperse tutorial.
Patch contributed by VTT Technical Research Centre of Finland Ltd and Institute
of Fluid Dynamics, Helmholtz-Zentrum Dresden - Rossendorf (HZDR).
Using the noSlip boundary condition for rotating wall in an MRF region
interferes with post-processing by resetting the wall velocity to 0 rather than
preserving the value set by the MRF zone.
Removed possibility for the user to specify a driftRate in the constantDrift
model which is independent of a fvOptions mass source. The driftRate must be
calculated from/be consistent with the mass source in order to yield a particle
number conserving result.
Made calculation of the over-all Sauter mean diameter of an entire population
balance conditional on more than one velocityGroup being present. This diameter
field is for post-processing purposes only and would be redundant in case of one
velocityGroup being used.
Solution control is extended to allow for solution of the population balance
equation at the last PIMPLE loop only, using an optional switch. This can be
beneficial in terms of simulation time as well as coupling between the
population balance based diameter calculation and the rest of the equation
system.
Patch contributed by Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden - Rossendorf
(HZDR) and VTT Technical Research Centre of Finland Ltd.
This patch enables the reactingEulerFoam solvers to simulate polydisperse flow
situations, i.e. flows where the disperse phase is subject to a size
distribution.
The newly added populationBalanceModel class solves the integro-partial
differential population balance equation (PBE) by means of a class method, also
called discrete or sectional method. This approach is based on discretizing the
PBE over its internal coordinate, the particle volume. This yields a set of
transport equations for the number concentration of particles in classes with a
different representative size. These are coupled through their source-terms and
solved in a segregated manner. The implementation is done in a way, that the
total particle number and mass is preserved for coalescence, breakup and drift
(i.e. isothermal growth or phase change) processes, irrespective of the chosen
discretization over the internal coordinate.
A population balance can be split over multiple velocity (temperature) fields,
using the capability of reactingMultiphaseEulerFoam to solve for n momentum
(energy) equations. To a certain degree, this takes into account the dependency
of heat- and momentum transfer on the disperse phase diameter. It is also possible
to define multiple population balances, e.g. bubbles and droplets simultaneously.
The functionality can be switched on by choosing the appropriate phaseSystem
type, e.g. populationBalanceMultiphaseSystem and the newly added diameterModel
class called velocityGroup. To illustrate the use of the functionality, a
bubbleColumnPolydisperse tutorial was added for reactingTwoPhaseEulerFoam and
reactingMultiphaseEulerFoam.
Furthermore, a reactingEulerFoam-specific functionObject called sizeDistribution
was added to allow post-Processing of the size distribution, e.g. to obtain the
number density function in a specific region.
Patch contributed by Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden - Rossendorf
(HZDR) and VTT Technical Research Centre of Finland Ltd.
- Thermal phase change and wall boiling functionality has been generalized to
support two- and multi- phase simulations.
- Thermal phase change now also allows purePhaseModel, which simplifies case setup.
- The phaseSystem templates have been restructured in preparation of multiple
simultaneous mass transfer mechanisms. For example, combination of thermal phase
and inhomogeneous population balance models.
Patch contributed by VTT Technical Research Centre of Finland Ltd and Institute
of Fluid Dynamics, Helmholtz-Zentrum Dresden - Rossendorf (HZDR).
The fundamental properties provided by the specie class hierarchy were
mole-based, i.e. provide the properties per mole whereas the fundamental
properties provided by the liquidProperties and solidProperties classes are
mass-based, i.e. per unit mass. This inconsistency made it impossible to
instantiate the thermodynamics packages (rhoThermo, psiThermo) used by the FV
transport solvers on liquidProperties. In order to combine VoF with film and/or
Lagrangian models it is essential that the physical propertied of the three
representations of the liquid are consistent which means that it is necessary to
instantiate the thermodynamics packages on liquidProperties. This requires
either liquidProperties to be rewritten mole-based or the specie classes to be
rewritten mass-based. Given that most of OpenFOAM solvers operate
mass-based (solve for mass-fractions and provide mass-fractions to sub-models it
is more consistent and efficient if the low-level thermodynamics is also
mass-based.
This commit includes all of the changes necessary for all of the thermodynamics
in OpenFOAM to operate mass-based and supports the instantiation of
thermodynamics packages on liquidProperties.
Note that most users, developers and contributors to OpenFOAM will not notice
any difference in the operation of the code except that the confusing
nMoles 1;
entries in the thermophysicalProperties files are no longer needed or used and
have been removed in this commet. The only substantial change to the internals
is that species thermodynamics are now "mixed" with mass rather than mole
fractions. This is more convenient except for defining reaction equilibrium
thermodynamics for which the molar rather than mass composition is usually know.
The consequence of this can be seen in the adiabaticFlameT, equilibriumCO and
equilibriumFlameT utilities in which the species thermodynamics are
pre-multiplied by their molecular mass to effectively convert them to mole-basis
to simplify the definition of the reaction equilibrium thermodynamics, e.g. in
equilibriumCO
// Reactants (mole-based)
thermo FUEL(thermoData.subDict(fuelName)); FUEL *= FUEL.W();
// Oxidant (mole-based)
thermo O2(thermoData.subDict("O2")); O2 *= O2.W();
thermo N2(thermoData.subDict("N2")); N2 *= N2.W();
// Intermediates (mole-based)
thermo H2(thermoData.subDict("H2")); H2 *= H2.W();
// Products (mole-based)
thermo CO2(thermoData.subDict("CO2")); CO2 *= CO2.W();
thermo H2O(thermoData.subDict("H2O")); H2O *= H2O.W();
thermo CO(thermoData.subDict("CO")); CO *= CO.W();
// Product dissociation reactions
thermo CO2BreakUp
(
CO2 == CO + 0.5*O2
);
thermo H2OBreakUp
(
H2O == H2 + 0.5*O2
);
Please report any problems with this substantial but necessary rewrite of the
thermodynamic at https://bugs.openfoam.org
Henry G. Weller
CFD Direct Ltd.
with the more general and flexible 'postProcess' utility and '-postProcess' solver option
Rationale
---------
Both the 'postProcess' utility and '-postProcess' solver option use the
same extensive set of functionObjects available for data-processing
during the run avoiding the substantial code duplication necessary for
the 'foamCalc' and 'postCalc' utilities and simplifying maintenance.
Additionally consistency is guaranteed between solver data processing
and post-processing.
The functionObjects have been substantially re-written and generalized
to simplify development and encourage contribution.
Configuration
-------------
An extensive set of simple functionObject configuration files are
provided in
OpenFOAM-dev/etc/caseDicts/postProcessing
and more will be added in the future. These can either be copied into
'<case>/system' directory and included into the 'controlDict.functions'
sub-dictionary or included directly from 'etc/caseDicts/postProcessing'
using the '#includeEtc' directive or the new and more convenient
'#includeFunc' directive which searches the
'<etc>/caseDicts/postProcessing' directories for the selected
functionObject, e.g.
functions
{
#includeFunc Q
#includeFunc Lambda2
}
'#includeFunc' first searches the '<case>/system' directory in case
there is a local configuration.
Description of #includeFunc
---------------------------
Specify a functionObject dictionary file to include, expects the
functionObject name to follow (without quotes).
Search for functionObject dictionary file in
user/group/shipped directories.
The search scheme allows for version-specific and
version-independent files using the following hierarchy:
- \b user settings:
- ~/.OpenFOAM/\<VERSION\>/caseDicts/postProcessing
- ~/.OpenFOAM/caseDicts/postProcessing
- \b group (site) settings (when $WM_PROJECT_SITE is set):
- $WM_PROJECT_SITE/\<VERSION\>/caseDicts/postProcessing
- $WM_PROJECT_SITE/caseDicts/postProcessing
- \b group (site) settings (when $WM_PROJECT_SITE is not set):
- $WM_PROJECT_INST_DIR/site/\<VERSION\>/caseDicts/postProcessing
- $WM_PROJECT_INST_DIR/site/caseDicts/postProcessing
- \b other (shipped) settings:
- $WM_PROJECT_DIR/etc/caseDicts/postProcessing
An example of the \c \#includeFunc directive:
\verbatim
#includeFunc <funcName>
\endverbatim
postProcess
-----------
The 'postProcess' utility and '-postProcess' solver option provide the
same set of controls to execute functionObjects after the run either by
reading a specified set of fields to process in the case of
'postProcess' or by reading all fields and models required to start the
run in the case of '-postProcess' for each selected time:
postProcess -help
Usage: postProcess [OPTIONS]
options:
-case <dir> specify alternate case directory, default is the cwd
-constant include the 'constant/' dir in the times list
-dict <file> read control dictionary from specified location
-field <name> specify the name of the field to be processed, e.g. U
-fields <list> specify a list of fields to be processed, e.g. '(U T p)' -
regular expressions not currently supported
-func <name> specify the name of the functionObject to execute, e.g. Q
-funcs <list> specify the names of the functionObjects to execute, e.g.
'(Q div(U))'
-latestTime select the latest time
-newTimes select the new times
-noFunctionObjects
do not execute functionObjects
-noZero exclude the '0/' dir from the times list, has precedence
over the -withZero option
-parallel run in parallel
-region <name> specify alternative mesh region
-roots <(dir1 .. dirN)>
slave root directories for distributed running
-time <ranges> comma-separated time ranges - eg, ':10,20,40:70,1000:'
-srcDoc display source code in browser
-doc display application documentation in browser
-help print the usage
pimpleFoam -postProcess -help
Usage: pimpleFoam [OPTIONS]
options:
-case <dir> specify alternate case directory, default is the cwd
-constant include the 'constant/' dir in the times list
-dict <file> read control dictionary from specified location
-field <name> specify the name of the field to be processed, e.g. U
-fields <list> specify a list of fields to be processed, e.g. '(U T p)' -
regular expressions not currently supported
-func <name> specify the name of the functionObject to execute, e.g. Q
-funcs <list> specify the names of the functionObjects to execute, e.g.
'(Q div(U))'
-latestTime select the latest time
-newTimes select the new times
-noFunctionObjects
do not execute functionObjects
-noZero exclude the '0/' dir from the times list, has precedence
over the -withZero option
-parallel run in parallel
-postProcess Execute functionObjects only
-region <name> specify alternative mesh region
-roots <(dir1 .. dirN)>
slave root directories for distributed running
-time <ranges> comma-separated time ranges - eg, ':10,20,40:70,1000:'
-srcDoc display source code in browser
-doc display application documentation in browser
-help print the usage
The functionObjects to execute may be specified on the command-line
using the '-func' option for a single functionObject or '-funcs' for a
list, e.g.
postProcess -func Q
postProcess -funcs '(div(U) div(phi))'
In the case of 'Q' the default field to process is 'U' which is
specified in and read from the configuration file but this may be
overridden thus:
postProcess -func 'Q(Ua)'
as is done in the example above to calculate the two forms of the divergence of
the velocity field. Additional fields which the functionObjects may depend on
can be specified using the '-field' or '-fields' options.
The 'postProcess' utility can only be used to execute functionObjects which
process fields present in the time directories. However, functionObjects which
depend on fields obtained from models, e.g. properties derived from turbulence
models can be executed using the '-postProcess' of the appropriate solver, e.g.
pisoFoam -postProcess -func PecletNo
or
sonicFoam -postProcess -func MachNo
In this case all required fields will have already been read so the '-field' or
'-fields' options are not be needed.
Henry G. Weller
CFD Direct Ltd.
This changes simplifies the specification of functionObjects in
controlDict and is consistent with the 'libs' option in controlDict to
load special solver libraries.
Support for the old 'functionObjectLibs' name is supported for backward compatibility.
to have the prefix 'write' rather than 'output'
So outputTime() -> writeTime()
but 'outputTime()' is still supported for backward-compatibility.
Also removed the redundant secondary-writing functionality from Time
which has been superseded by the 'writeRegisteredObject' functionObject.
for consistency with the time controls in controlDict and to avoid
unnecessary confusion. All code and tutorials have been updated.
The old names 'outputControl' and 'outputInterval' are but supported for
backward compatibility but deprecated.
See http://www.openfoam.org/mantisbt/view.php?id=2076
- .org is the file extension for emacs org-mode as well
- .orig is more to the point (.org isn't always recognized as "original")
- .original is too long, although more consistent with the convention
of source code file naming
Update script contributed by Bruno Santos
