coneInjection has been extended to include the functionality of
coneNozzleInjection, and the latter has been removed.
Some parameters have changed names. The "positionAxis" entry from
coneInjection has been removed in preferance of coneNozzleInjection's
single "position" and "direction" entries. This means that only one
injection site is possible per model (dictionary substitutions mean that
only minimal additions are required to add further injection sites with
the same parameters). The name of the velocity magnitude has been
standardised as "Umag" and "innerDiameter" and "outerDiamater" have been
renamed "dInner" and "dOuter" for consistency with the inner and outer
spray angles.
Velocity magnitude and diameters are no longer read when they are not
required.
The randomisation has been altered so that the injections generate a
uniform distribution on an cross section normal to the direction of
injection. Previously there was an unexplained bias towards the
centreline.
An example specification with a full list of parameters is shown below.
injectionModels
{
model1
{
type coneInjection;
// Times
SOI 0;
duration 1;
// Quantities
massTotal 0; // <-- not used with these settings
parcelBasisType fixed;
parcelsPerSecond 1000000;
flowRateProfile constant 1;
nParticle 1;
// Sizes
sizeDistribution
{
type fixedValue;
fixedValueDistribution
{
value 0.0025;
}
}
// Geometry
positions (-0.15 -0.1 0);
directions (1 0 0);
thetaInner 0;
thetaOuter 45;
// - Inject at a point
injectionMethod point;
// - Or, inject over a disc:
/*
injectionMethod disc;
dInner 0;
dOuter 0.05;
*/
// Velocity
// - Inject with constant velocity
flowType constantVelocity;
Umag 1;
// - Or, inject with flow rate and discharge coefficient
// This also requires massTotal, dInner and dOuter
/*
flowType flowRateAndDischarge;
Cd 0.9;
*/
// - Or, inject at a pressure
/*
flowType pressureDrivenVelocity;
Pinj 10e5;
*/
}
model2
{
// The same as model1, but at a different position
$model1;
position (-0.15 0.1 0);
}
}
to simplify reacting case setup.
Tutorials
tutorials/combustion/chemFoam/ic8h18_TDAC
tutorials/combustion/reactingFoam/RAS/SandiaD_LTS
tutorials/combustion/reactingFoam/laminar/counterFlowFlame2DLTS_GRI_TDAC
tutorials/combustion/reactingFoam/laminar/counterFlowFlame2D_GRI_TDAC
updated to benefit from the new configuration files.
Patch contributed by Francesco Contino
to avoid the need to evaluate departure functions and simplify evaluation of the
temperature. In general it makes more sense to use and e/Cv based
thermodynamics when solving for internal energy rather than h/Cp and have
convert between the energy forms.
All related tutorials and test cases have also been updated.
Changed liquid thermo from sensibleEnthalpy to sensibleInternalEnergy in
tutorials. It is generally more convergent and stable to solve for internal
energy if the fluid is incompressible or weakly compressible.
This provides more flexibility in specifying the allowed internal and boundary
extrema.
For driftFluxFoam and other settling problems it is beneficial to set the
boundaryExtremaCoeff to 1 to allow rapid accumulation of the partials on the
bottom wall (which was the previous default behaviour) but this is not suitable
for many Euler-Euler cases for which a uniform etrema coefficient is preferable,
either 0 or a small value.
Now by default boundaryExtremaCoeff is set to extremaCoeff which defaults to 0
which provides the behaviour before
OpenFOAM-dev commit cb2bc60fa5
and the driftFluxFoam tutorials have been updated adding
boundaryExtremaCoeff 1;
to the MULES controls in fvSolution so reproduce the previous behaviour.
The LBend was set to run for 2 s, but at about 1.95 s the packed region
builds up to the inlet and the simulation diverges. The end time has
been reduced to 1.9 s so that this does not occur.
snappyHexMesh now generates a face-zone for the AMI-s, and createBaffles
and mergeOrSplitPoints -split are used to create the patches. Before,
snappy generated AMI patches directly, which were then converted to
AMI-s with createPatch.
This way, the AMI-s match exactly at the start of the simulation. For
more complicated cases that may be derived from this tutorial, this
could be important.
With the -noFields option the mesh is subset but the fields are not changed.
This is useful when the field fields have been created to correspond to the mesh
after the mesh subset.
To switch-off radiation set
radiationModel none;
in radiationProperties which instantiates "null" model that does not read any
data or coefficients or evaluate any fields.
The semiPermeableBaffleMassFraction boundary condition can now calculate
the mass flux as proportional to the difference in mole fraction or
partial pressure. A mass fraction difference driven transfer is also
still possible. An additional keyword, "input" has been added which is
used to select the variable used to calculate the transfer. An example
specification is as follows:
baffle
{
type semiPermeableBaffleMassFraction;
samplePatch membranePipe;
c 0.1;
input massFraction;
value uniform 0;
}
In order to facilitate this, a "W" method to get the molar mass on a
patch has been added to the thermodynamics. To avoid name-clashes,
methods that generate per-species molar masses have been renamed "Wi".
This work was supported by Georg Skillas, at Evonik
The sampled sets have been renamed in a more explicit and consistent
manner, and two new ones have also been added. The available sets are as
follows:
arcUniform: Uniform samples along an arc. Replaces "circle", and
adds the ability to sample along only a part of the circle's
circumference. Example:
{
type arcUniform;
centre (0.95 0 0.25);
normal (1 0 0);
radial (0 0 0.25);
startAngle -1.57079633;
endAngle 0.52359878;
nPoints 200;
axis x;
}
boundaryPoints: Specified point samples associated with a subset of
the boundary. Replaces "patchCloud". Example:
{
type boundaryPoints;
patches (inlet1 inlet2);
points ((0 -0.05 0.05) (0 -0.05 0.1) (0 -0.05 0.15));
maxDistance 0.01;
axis x;
}
boundaryRandom: Random samples within a subset of the boundary.
Replaces "patchSeed", but changes the behaviour to be entirely
random. It does not seed the boundary face centres first. Example:
{
type boundaryRandom;
patches (inlet1 inlet2);
nPoints 1000;
axis x;
}
boxUniform: Uniform grid of samples within a axis-aligned box.
Replaces "array". Example:
{
type boxUniform;
box (0.95 0 0.25) (1.2 0.25 0.5);
nPoints (2 4 6);
axis x;
}
circleRandom: Random samples within a circle. New. Example:
{
type circleRandom;
centre (0.95 0 0.25);
normal (1 0 0);
radius 0.25;
nPoints 200;
axis x;
}
lineFace: Face-intersections along a line. Replaces "face". Example:
{
type lineFace;
start (0.6 0.6 0.5);
end (0.6 -0.3 -0.1);
axis x;
}
lineCell: Cell-samples along a line at the mid-points in-between
face-intersections. Replaces "midPoint". Example:
{
type lineCell;
start (0.5 0.6 0.5);
end (0.5 -0.3 -0.1);
axis x;
}
lineCellFace: Combination of "lineFace" and "lineCell". Replaces
"midPointAndFace". Example:
{
type lineCellFace;
start (0.55 0.6 0.5);
end (0.55 -0.3 -0.1);
axis x;
}
lineUniform: Uniform samples along a line. Replaces "uniform".
Example:
{
type lineUniform;
start (0.65 0.3 0.3);
end (0.65 -0.3 -0.1);
nPoints 200;
axis x;
}
points: Specified points. Replaces "cloud" when the ordered flag is
false, and "polyLine" when the ordered flag is true. Example:
{
type points;
points ((0 -0.05 0.05) (0 -0.05 0.1) (0 -0.05 0.15));
ordered yes;
axis x;
}
sphereRandom: Random samples within a sphere. New. Example:
{
type sphereRandom;
centre (0.95 0 0.25);
radius 0.25;
nPoints 200;
axis x;
}
triSurfaceMesh: Samples from all the points of a triSurfaceMesh.
Replaces "triSurfaceMeshPointSet". Example:
{
type triSurfaceMesh;
surface "surface.stl";
axis x;
}
The headers have also had documentation added. Example usage and a
description of the control parameters now exists for all sets.
In addition, a number of the algorithms which generate the sets have
been refactored or rewritten. This was done either to take advantage of
the recent changes to random number generation, or to remove ad-hoc
fixes that were made unnecessary by the barycentric tracking algorithm.
including third-body and pressure dependent derivatives, and derivative of the
temperature term. The complete Jacobian is more robust than the incomplete and
partially approximate form used previously and improves the efficiency of the
stiff ODE solvers which rely on the Jacobian.
Reaction rate evaluation moved from the chemistryModel to specie library to
simplfy support for alternative reaction rate expressions and associated
Jacobian terms.
Temperature clipping included in the Reaction class. This is inactive by default
but for most cases it is advised to provide temperature limits (high and
low). These are provided in the foamChemistryFile with the keywords Thigh and
Tlow. When using chemkinToFoam these values are set to the limits of the Janaf
thermodynamic data. With the new Jacobian this temperature clipping has proved
very beneficial for stability and for some cases essential.
Improvement of the TDAC MRU list better integrated in add and grow functions.
To get the most out of this significant development it is important to re-tune
the ODE integration tolerances, in particular the absTol in the odeCoeffs
sub-dictionary of the chemistryProperties dictionary:
odeCoeffs
{
solver seulex;
absTol 1e-12;
relTol 0.01;
}
Typically absTol can now be set to 1e-8 and relTol to 0.1 except for ignition
time problems, and with theses settings the integration is still robust but for
many cases a lot faster than previously.
Code development and integration undertaken by
Francesco Contino
Henry G. Weller, CFD Direct
