A surface geometry file should be stored in
$FOAM_TUTORIALS/resources/geometry if it is used in multiple cases,
otherwise it should be stored locally to the case. This change enforces
that across all tutorials.
An adsorption condition has been added for species mass fraction. This
models a surface on which one or more species deposit at a rate
proportional to the quantity of that specie present. The property that
the rate is assumed proportional to can be chosen to be mass fraction,
mole fraction, molar concentration, or partial pressure.
Example specification in 0/CH4, 0/O2, etc...:
<patchName>
{
type adsorptionMassFraction;
property molarConcentration;
c 1e-3; // <-- Transfer coefficient
value $internalField;
}
"c" is the constant of proportionality between the property value and
the mass transfer rate. If a specie does not adsorb, this should be set
to zero, or be omitted entirely.
This condition must be supplied for all species, and corresponding
specie transfer boundary conditions must also be applied to velocity and
temperature.
Example specification in 0/U and 0/T:
<patchName>
{
type specieTransferVelocity;
value $internalField;
}
<patchName>
{
type specieTransferTemperature;
value $internalField;
}
In addition, the semi-permeable baffle conditions have been refactored
to share functionality with the new adsorption conditions. They can now
also be used with the species-transfer temperature condition, which
corrects an energy error that was present previously. The parameter
"input" has been renamed "property", consistently with the adsorption
entries listed above. Molar concentration has also been added as an
option for the property driving the transfer, so the available controls
are the same as for adsorption.
Example specification in 0/CH4, 0/O2, etc...:
<patchName>
{
type semiPermeableBaffleMassFraction;
samplePatch <neighbourPatchName>;
property molarConcentration;
c 1e-3; // <-- Transfer coefficient
value $internalField;
}
<neighbourPatchName>
{
type semiPermeableBaffleMassFraction;
samplePatch <patchName>;
property molarConcentration;
c 1e-3; // <-- Transfer coefficient
value $internalField;
}
Velocity and temperature conditions should be set in the same way as for
adsorption.
In order for the temperature condition to function satisfactorily and
not introduce unphysical variations in temperature as a result of the
linearisation to an energy boundary condition, two new base classes for
temperature conditions which explicitly set the parameters of either
gradient or mixed energy conditions have been added. The mixed condition
forms the base of the specieTransferTemperature condition.
As a result of its generalisation, the library has been renamed from
"libsemiPermeableBaffle.so" to "libspecieTransfer.so".
derived from solidThermo. This allows the standard heat transfer boundary
conditions, for example externalWallHeatFluxTemperature, to be used with
solidDisplacementFoam and also significantly simplifies the code.
Additionally solidDisplacementFoam and solidEquilibriumDisplacementFoam have
been updated to handle spatially varying physical properties in a conservative
manner both for the stress and heat transfer. This means that the stress field
sigma is now dynamic rather than kinematic as it was previously. For uniform
property fields the behaviour of the solvers is the same as it was before this
update.
This part of the name is unnecessary, as it is clear from context that
the name refers to a reaction. The selector has been made backwards
compatible so that old names will still read successfuly.
Reaction names are now consistently camel-cased for readability. Most
names have not been affected because the reaction rate name is a proper
noun and is therefore already capitalised (e.g., Arrhenius, Janev,
Landau, etc ...). Reactions that have been affected are as follows.
Old name New name
irreversibleinfiniteReaction irreversibleInfiniteReaction
irreversiblepowerSeriesReaction irreversiblePowerSeriesReaction
irreversiblethirdBodyArrheniusReaction irreversibleThirdBodyArrheniusReaction
nonEquilibriumReversibleinfiniteReaction nonEquilibriumReversibleInfiniteReaction
nonEquilibriumReversiblethirdBodyArrheniusReaction nonEquilibriumReversibleThirdBodyArrheniusReaction
reversibleinfiniteReaction reversibleInfiniteReaction
reversiblepowerSeriesReaction reversiblePowerSeriesReaction
reversiblethirdBodyArrheniusReaction reversibleThirdBodyArrheniusReaction
irreversiblefluxLimitedLangmuirHinshelwoodReaction irreversibleFluxLimitedLangmuirHinshelwoodReaction
irreversiblesurfaceArrheniusReaction irreversibleSurfaceArrheniusReaction
reversiblesurfaceArrheniusReaction reversibleSurfaceArrheniusReaction
Function1 has been generalised in order to provide functionality
previously provided by some near-duplicate pieces of code.
The interpolationTable and tableReader classes have been removed and
their usage cases replaced by Function1. The interfaces to Function1,
Table and TableFile has been improved for the purpose of using it
internally; i.e., without user input.
Some boundary conditions, fvOptions and function objects which
previously used interpolationTable or other low-level interpolation
classes directly have been changed to use Function1 instead. These
changes may not be backwards compatible. See header documentation for
details.
In addition, the timeVaryingUniformFixedValue boundary condition has
been removed as its functionality is duplicated entirely by
uniformFixedValuePointPatchField.
Integral evaluations have been implemented for all the ramp function1-s,
as well as the sine and square wave. Bounds handling has also been added
to the integration of table-type functions.
In addition, the sine wave "t0" paramater has been renamed "start" for
consistency with the ramp functions.
Description
Calculates the thermal comfort quantities predicted mean vote (PMV) and
predicted percentage of dissatisfaction (PPD) based on DIN ISO EN 7730:2005.
Usage
\table
Property | Description | Required | Default value
clothing | The insulation value of the cloth | no | 0
metabolicRate | The metabolic rate | no | 0.8
extWork | The external work | no | 0
Trad | Radiation temperature | no | -1
relHumidity | Relative humidity of the air | no | 50
pSat | Saturation pressure of water | no | -1
tolerance | Residual control for the cloth temperature | no | 1e-5
maxClothIter | Maximum number of iterations | no | 0
meanVelocity | Use a constant mean velocity in the whole domain | no |\
false
\endtable
\table
Predicted Mean Vote (PMV) | evaluation
+ 3 | hot
+ 2 | warm
+ 1 | slightly warm
+ 0 | neutral
- 1 | slightly cool
- 2 | cool
- 3 | cold
\endtable
\verbatim
comfortAnalysis
{
type comfort;
libs ("libfieldFunctionObjects.so");
executeControl writeTime;
writeControl writeTime;
}
\endverbatim
The new tutorial case heatTransfer/buoyantSimpleFoam/comfortHotRoom is provided
to demonstrate the calculation of PMV and PPD using the comfort functionObject.
This work is based on code and case contributed by Tobias Holzmann.
Mass transfer rates now have a more comprehensive naming convention.
"dmdt" means a bulk/mixture transfer, whilst "dmidt" is for a
specie-specific transfer. "dmdt" implies a transfer into a phase, whilst
"dmdtf" means a transfer across an interface. Tables or lists of
transfers are denoted by pluralising the name with the suffix "s"; e.g.,
"dmdtfs". All registered mass transfer rate fields have names which
include the name of the sub-model or phase system which generated them.
The phaseTransfer models have been changed so that the mixture and the
specie-specific mass transfers are independent. This simplifies the
naming convention required for registering the resulting mass transfers
and reduces the amount of logic necessary in the phase system.
The inheritance pattern of the alphat wall functions has been altered so
that the code and parameters relating to phase change are reused, and so
that the base (the Jayatilleke wall function) more closely resembles the
library implementation. This should make it easier to remove it when the
library function is generalised enough to use it directly.
The phaseSystem::zero*Field construction functions have been removed as
their behaviour regarding registration was not clear, and in most
instances of their usage the GeometriField<...>::New methods are
similarly convenient.
This change extends phaseTransferModel and PhaseTransferPhaseSystem to
allow non-uniform specie transfer between phases.
A reactionDriven phaseTransfer model is added which represents change of
selected species from one phase to another due to a reaction occurring
within one of the phases.
Following the change, the reactionDriven nucleation models and the
phaseChange drift models in populationBalanceModel have been updated to
use the new functionality in PhaseTransferPhaseSystem. The
PopulationBalancePhaseSystem has been simplified significantly as a
result.
The functionality is demonstrated by a tutorial case simulating the
vapour phase synthesis of titania by titanium tetrachloride oxidation
where both nucleation and surface reactions models are active at the
same time.
Patch contributed by VTT Technical Research Centre of Finland Ltd and
Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden - Rossendorf (HZDR).
to enable the calculation of the residence time for a fluid; mainly used in HVAC
analysis. E.g. residence time of air inside a ventilated room, see the new
tutorial roomResidenceTime.
Contributed by Tobias Holzmann
Rather than defining patches for all external block faces to provide name and
type use the defaultPatch entry to collect undefined faces into a single named
and typed patch, e.g.
defaultPatch
{
name walls;
type wall;
}
Description
Time-dependent external force restraint using Function1.
Usage
Example applying a constant force to the floatingObject:
restraints
{
force
{
type externalForce;
body floatingObject;
location (0 0 0);
force (100 0 0);
}
}
Based on code contributed by SeongMo Yeon
Resolves contribution request https://bugs.openfoam.org/view.php?id=3358
The side surfaces in this tutorial have been made symmetry planes to
match the corresponding boundaries in the film region, and the top has
had its pressure condition changed to totalPressure. The case now runs
successfully to completion.
Previously the pressure-velocity boundary condition combination on the
non-film patches was incorrect in that in regions of outflow a pressure
value was not being specified. This resulted in divergence.
All multi-specie solvers function on the assumption that the
mass-diffusivities of the different species are the same. A consequence
of this is that the diffusivities of energy and mass must be the same,
otherwise mass diffusivity results in unphysical temperature
fluctuations. This change enforces this requirement across all
multi-species solvers.
For the same reason, the turbulent Schmidt number has been removed from
the multi-component phase model in reactingEulerFoam. In order to obey
physical constraints this Schmidt number had to be exactly the same as
the Prandtl number. This condition is now enforced by the solver, rather
than relying on the input being correct.
Interface composition models are now specified in
constant/phaseProperties like so:
interfaceComposition.gas
(
(gas and water)
{
// ...
}
(gas and oil)
{
// ...
}
);
interfaceComposition.water
(
(water and gas)
{
// ...
}
// ...
);
// ...
I.e., the models associated with diffusive transfer within a phase
"<phase>" are specified in the list "interfaceComposition.<phase>".
Within the list, models are specified in unordered phase pairs
corresponding to the interface.
This replaces a system where models were specified in a single
interfaceComposition list, with the ordered pair entry "(<phase1> in
<phase2>)" meaning transfer within phase1 at the interface with phase2.
This ordered pair syntax is otherwise used for distinguishing between
continuous and dispersed phases. This dual meaning was considered
counter-intuitive. The new entries also more closely resemble the
associated two-resistance heat and mass transfer model specifications.
There are now many types of mass transfer, so massTransfer is now too
generic a term for what these models do. These models generate a
diffusivity which when multiplied by a concentration difference results
in mass transfer, hence the new name.
This change is not backwards compatible. Cases running the interface
composition system will need "massTransfer" entries renamed to
"diffusiveMassTransfer".
The new optional entry alphap is the as phase fraction below which bubble
generated turbulence is included. The default is 1 for backward compatibility.
The purpose of this limiter is to avoid spurious turbulence generation at and
around the interface where bubbles are not present.
If the functionObject requires an object list rather than a field list the
non-named arguments are now inserted into the object list, for example
functions
{
#includeFunc writeObjects(kEpsilon:G)
}
which is equivalent to
functions
{
#includeFunc writeObjects(objects = (kEpsilon:G))
}
For example the generation term in the k-epsilon turbulence kEpsilon:G is a
temporary field that is specifically named and registered so that it can be
looked-up be the wall-function boundary conditions and requires slightly
different handling compared to normal temporary fields which are not registered.
The tutorials/incompressible/simpleFoam/pitzDaily case now demostrates this
functionality with the addition of
cacheTemporaryObjects
(
kEpsilon:G
);
functions
{
#includeFunc writeObjects(objects = (kEpsilon:G))
}
in controlDict which caches kEpsilon:G and writes it at every write time.
Description
Reciprocal polynomial equation of state for liquids and solids
\f[
1/\rho = C_0 + C_1 T + C_2 T^2 - C_3 p - C_4 p T
\f]
This polynomial for the reciprocal of the density provides a much better fit
than the equivalent polynomial for the density and has the advantage that it
support coefficient mixing to support liquid and solid mixtures in an
efficient manner.
Usage
\table
Property | Description
C | Density polynomial coefficients
\endtable
Example of the specification of the equation of state for pure water:
\verbatim
equationOfState
{
C (0.001278 -2.1055e-06 3.9689e-09 4.3772e-13 -2.0225e-16);
}
\endverbatim
Note: This fit is based on the small amount of data which is freely
available for the range 20-65degC and 1-100bar.
This equation of state is a much better fit for water and other liquids than
perfectFluid and in general polynomials for the reciprocal of the density
converge much faster than polynomials of the density. Currently rPolynomial is
quadratic in the temperature and linear in the pressure which is sufficient for
modest ranges of pressure typically encountered in CFD but could be extended to
higher order in pressure and/temperature if necessary. The other huge advantage
in formulating the equation of state in terms of the reciprocal of the density
is that coefficient mixing is simple.
Given these advantages over the perfectFluid equation of state the libraries and
tutorial cases have all been updated to us rPolynomial rather than perfectFluid
for liquids and water in particular.
solidChemistryModel is not implemented in a general way but specialised to form
the basis of the highly specific pyrolysis mode. The handling of reactions is
hard-coded for forward reactions only, the Jacobian was present but incomplete
so any ODE solvers requiring the Jacobian would either fail, diverge or produce
incorrect results. It is not clear if many or any parts of the
solidChemistryModel are correct, in particular there is no handling for the
solid surface area per unit volume. After a lot of refactoring work it has
become clear that solidChemistryModel needs a complete rewrite and can benefit
from all the recent development work done on the now more general
StandardChemistryModel.
This change adds representation of the shape of a dispersed phase. A
layer has been added to model the relationship between the
characteristic volume of a sizeGroup and its physical diameter.
Previously this relationship was represented by a constant form factor.
Currently, two shape models are available:
- spherical
- fractal (for modelling fractal agglomerates)
The latter introduces the average surface area to volume ratio, kappa,
of the entities in a size group as a secondary field-dependent internal
variable to the population balance equation, which makes the population
balance approach "quasi-"bivariate. From kappa and a constant mass
fractal dimension, a collisional diameter can be derived which affects
the coagulation rates computed by the following models:
- ballisticCollisions
- brownianCollisions
- DahnekeInterpolation
- turbulentShear
The fractal shape modelling also takes into account the effect of sintering
of primary particles on the surface area of the aggregate.
Further additions/changes:
- Time scale filtering for handling large drag and heat transfer
coefficients occurring for particles in the nanometre range
- Aerosol drag model based on Stokes drag with a Knudsen number based
correction (Cunningham correction)
- Reaction driven nucleation
- A complete redesign of the sizeDistribution functionObject
The functionality is demonstrated by a tutorial case simulating the
vapour phase synthesis of titania by titanium tetrachloride oxidation.
Patch contributed by Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden -
Rossendorf (HZDR) and VTT Technical Research Centre of Finland Ltd.
All reactingEulerFoam wall boiling tutorials have been replaced with
cases that are more representative of real applications.
The wall boiling tutorials for reactingTwoPhaseEulerFoam are:
RAS/wallBoiling:
Axi-symmetric wall boiling case with constant bubble diameter
RAS/wallBoilingPolyDisperse:
As wallBoiling, but with a homogenous class method population
balance for modelling the bubble diameters
RAS/wallBoilingIATE:
As wallBoiling, but with an interfacial area transport equation
for modelling the bubble diameters
The wall boiling tutorials for reactingMultiphaseEulerFoam are:
RAS/wallBoilingPolydisperseTwoGroups:
As wallBoiling, but with an inhomogenous class method population
balance for modelling the bubble diameters
Patch contributed by Juho Peltola, VTT.
