Description
Simple solidification porosity model
This is a simple approximation to solidification where the solid phase
is represented as a porous blockage with the drag-coefficient evaluated from
\f[
S = - \alpha \rho D(T) U
\f]
where
\vartable
\alpha | Optional phase-fraction of solidifying phase
D(T) | User-defined drag-coefficient as function of temperature
\endvartable
Note that the latent heat of solidification is not included and the
temperature is unchanged by the modelled change of phase.
Example of the solidification model specification:
\verbatim
type solidification;
solidificationCoeffs
{
// Solidify between 330K and 330.5K
D table
(
(330.0 10000) // Solid below 330K
(330.5 0) // Liquid above 330.5K
);
// Optional phase-fraction of solidifying phase
alpha alpha.liquid;
// Solidification porosity is isotropic
// use the global coordinate system
coordinateSystem
{
type cartesian;
origin (0 0 0);
coordinateRotation
{
type axesRotation;
e1 (1 0 0);
e2 (0 1 0);
}
}
}
\endverbatim
Description
Simple solidification porosity model
This is a simple approximation to solidification where the solid phase
is represented as a porous blockage with the drag-coefficient evaluated from
\f[
S = - \rho D(T) U
\f]
where
\vartable
D(T) | User-defined drag-coefficient as function of temperature
\endvartable
Note that the latent heat of solidification is not included and the
temperature is unchanged by the modelled change of phase.
Example of the solidification model specification:
\verbatim
type solidification;
solidificationCoeffs
{
// Solidify between 330K and 330.5K
D table
(
(330.0 10000) // Solid below 330K
(330.5 0) // Liquid above 330.5K
);
// Solidification porosity is isotropic
// use the global coordinate system
coordinateSystem
{
type cartesian;
origin (0 0 0);
coordinateRotation
{
type axesRotation;
e1 (1 0 0);
e2 (0 1 0);
}
}
}
\endverbatim
if convergence is not achieved within the maximum number of iterations.
Sometimes, particularly running in parallel, PBiCG fails to converge or diverges
without warning or obvious cause leaving a solution field containing significant
errors which can cause divergence of the application. PBiCGStab is more robust
and does not suffer from the problems encountered with PBiCG.
The previous time-step compression flux is not valid/accurate on the new mesh
and it is better to re-calculate it rather than map it from the previous mesh to
the new mesh.
By default snappyHexMesh writes files relating to the hex-splitting process into
the polyMesh directory: cellLevel level0Edge pointLevel surfaceIndex
but by setting the noRefinement flag:
writeFlags
(
noRefinement
.
.
.
);
these optional files which are generally not needed are not written.
If you run the three stages of snappyHexMesh separately or run a dynamic mesh
solver supporting refinement and unrefinement these files are needed
and "noRefinement" should not be set.
unless the blockMeshDict is in the polyMesh directory or the "-noClean" option
is specified.
This avoids problems running snappyHexMesh without first clearing files from
polyMesh which interfere with the operation of snappyHexMesh.
The files relating to the hex refinement are written out explicitly both by
snappyHexMesh and dynamicRefineFvMesh and hence should be set "NO_WRITE" rather
than "AUTO_WRITE" to avoid writing them twice. This change corrects the
handling of the "refinementHistory" file which should not be written by
snappyHexMesh.
Avoids slight phase-fraction unboundedness at entertainment BCs and improved
robustness.
Additionally the phase-fractions in the multi-phase (rather than two-phase)
solvers are adjusted to avoid the slow growth of inconsistency ("drift") caused
by solving for all of the phase-fractions rather than deriving one from the
others.
e.g.
fieldMinMax fieldMinMax write:
min(T) = 291 in cell 255535 at location (-0.262546 -0.538933 1.00574) on processor 9
max(T) = 336.298 in cell 419031 at location (1.7468 0.758405 8.10989) on processor 1
min(mag(U)) = 0 in cell 14990 at location (-0.0824383 1.68479 1.5349) on processor 0
max(mag(U)) = 652.341 in cell 218284 at location (0.609849 0.167247 1.00091) on processor 12
New reactingFoam tutorial counterFlowFlame2DLTS_GRI_TDAC demonstrates this new
functionality.
Additionally the ISAT table growth algorithm has been further optimized
providing an overall speedup of between 15% and 38% for the tests run so far.
Updates to TDAC and ISAT provided by Francesco Contino.
Implementation updated and integrated into OpenFOAM-dev by
Henry G. Weller, CFD Direct Ltd with the help of Francesco Contino.
Original code providing all algorithms for chemistry reduction and
tabulation contributed by Francesco Contino, Tommaso Lucchini, Gianluca
D’Errico, Hervé Jeanmart, Nicolas Bourgeois and Stéphane Backaert.
e.g. in tutorials/heatTransfer/buoyantSimpleFoam/externalCoupledCavity/0/T
hot
{
type externalCoupledTemperature;
commsDir "${FOAM_CASE}/comms";
file "data";
initByExternal yes;
log true;
value uniform 307.75; // 34.6 degC
}
Previously both 'file' and 'fileName' were used inconsistently in different
classes and given that there is no confusion or ambiguity introduced by using
the simpler 'file' rather than 'fileName' this change simplifies the use and
maintenance of OpenFOAM.
