psiReactionThermo- and rhoReactionThermo-s now derive from an additional
fluidReactionThermo class and are included on a corresponding run-time
selection table.
This means all multi-specie solvers can now be used with either
compressibility/psi- or density/rho-based thermodynamic models, in the
same way that non-reacting solvers can.
rhoReactingFoam has been removed, as it is no longer necessary now that
reactingFoam can operate with density-based thermodynamics.
rhoReactingBuoyantFoam has also been renamed buoyantReactingFoam to
reflect the fact that it is no longer a variant specific to
density-based thermodynamics; it can now operate with
compressibility-based thermodynamic models as well.
The change is fully backwards compatible. All cases should continue to
run without modification, apart from the fact that a different solver
might need to be called.
using the new nonUniformTable to interpolate between the values vs temperature
provided. All properties (density, heat capacity, viscosity and thermal
conductivite) are considered functions of temperature only and the equation of
state is thus incompressible. Built-in mixing rules corresponding to those in
the other thermo and transport models are not efficient or practical for
tabulated data and so these models are currently only instantiated for the pure
specie/mixture rhoThermo package but a general external mixing method will be
added in the future.
To handle reactions the Jacobian function dKcdTbyKc has been rewritten to use
the Gstd and S functions directly removing the need for the miss-named dGdT
function and hence removing the bugs in the implementation of that function for
some of the thermo models. Additionally the Hc() function has been renamed
Hf() (heat of formation) which is more commonly used terminology and consistent
with the internals of the thermo models.
The pressure provided to the patch and cellSet property evaluation functions is
always that stored by the thermodynamics package as is the composition which is
provided internally; given that these functions are used in boundary conditions
to estimate changes in heat flux corresponding to changes in temperature only
there is no need for another pressure to be provided. In order that the
pressure and composition treatment are consistent and to maintain that during
future rationalisation of the handling of composition it makes sense to remove
this unnecessary pressure argument.
This provides a virtual layer for which to evaluate properties of
individual species, across the entire domain. This is necessary when
computing the properties of reactions and phase changes, and this
provides a means of doing so without templating the sub-modelling on the
thermodynamics type, or performing an inefficient cell-loop over the
equivalent scalar methods.
Absolute enthalpy functions have also been added into basicThermo and
heThermo. Again, this information is likely to be necessary when
computing thermal aspects of phase changes.
A number of templated generic property calculation methods have also
been implemented in heThermo, and the various specific functions
rewritten in terms of them. This has removed the duplication of the code
associated with constructing the field types.
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 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.
Mixture molecular weight is now evaluated in heThermo like everything
else, relying on the low level specie mixing rules. Units have also been
corrected.
This allows single, multi-phase and VoF compressible simulations to be performed
with the accurate thermophysical property functions for liquids provided by the
liquidProperty classes. e.g. in the
multiphase/compressibleInterFoam/laminar/depthCharge2D tutorial water can now be
specified by
thermoType
{
type heRhoThermo;
mixture pureMixture;
properties liquid;
energy sensibleInternalEnergy;
}
mixture
{
H2O;
}
as an alternative to the previous less accurate representation defined by
thermoType
{
type heRhoThermo;
mixture pureMixture;
transport const;
thermo hConst;
equationOfState perfectFluid;
specie specie;
energy sensibleInternalEnergy;
}
mixture
{
specie
{
molWeight 18.0;
}
equationOfState
{
R 3000;
rho0 1027;
}
thermodynamics
{
Cp 4195;
Hf 0;
}
transport
{
mu 3.645e-4;
Pr 2.289;
}
}
However the increase in accuracy of the new simpler and more convenient
specification and representation comes at a cost: the NSRDS functions used by
the liquidProperties classes are relatively expensive to evaluate and the
depthCharge2D case takes ~14% longer to run.
