Currently this is implemented only for the Antoine equation, for the
other more complex models an iterative inversion from pressure to
temperature is required.

In preparation for adding the Tsat function

for consistency with the evaluation of the interface temperature.

Generally this term has a VERY small effect on temperature, it is only
important for low-speed buoyancy-dominated flows.

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1755

See also http://cfd.direct/openfoam/energy-equation/

Now the specification of the LTS time scheme is simply:

ddtSchemes
{
    default         localEuler;
}

Select LTS via the ddtScheme:

    ddtSchemes
    {
        default         localEuler rDeltaT;
    }

The LTS algorithm is currently controlled with the standard settings in
controlDict, e.g.:

    maxCo           0.5;
    maxDeltaT       2e-8;

with the addition of the optional rDeltaT smoothing coefficient:

    rDeltaTSmoothingCoeff 0.02;

which defaults to 0.02.

    ddtSchemes
    {
        default         localEuler rDeltaT;
    }

LTS is selected by the ddt scheme e.g. in the
tutorials/multiphase/interFoam/ras/DTCHull case:

ddtSchemes
{
    default         localEuler rDeltaT;
}

LTSInterFoam is no longer needed now that interFoam includes LTS
support.

to support any number of phases

correction in MovingPhaseModel<BasePhaseModel>::correct()

to correspond to the phase dilatation rate.

to support any number of phases

to be phase-symmetric so that the results are independent of which
phase-fraction is solved.

Multi-species, mass-transfer and reaction support and multi-phase
structure provided by William Bainbridge.

Integration of the latest p-U and face-p_U algorithms with William's
multi-phase structure is not quite complete due to design
incompatibilities which needs further development.  However the
integration of the functionality is complete.

The results of the tutorials are not exactly the same for the
twoPhaseEulerFoam and reactingTwoPhaseEulerFoam solvers but are very
similar.  Further analysis in needed to ensure these differences are
physical or to resolve them; in the meantime the twoPhaseEulerFoam
solver will be maintained.

twoPhaseEulerFoam/interfacialModels/heatTransferModels/sphericalHeatTransfer: new heat-transfer model

Model which applies an analytical solution for heat transfer from the
surface of a sphere to the fluid within the sphere.

Provided by William Bainbridge

This is necessary to guarantee consistency between the residualAlpha
used for drag and buoyancy in a multi-phase system

fvOptions does not have the appropriate structure to support MRF as it
is based on option selection by user-specified fields whereas MRF MUST
be applied to all velocity fields in the particular solver.  A
consequence of the particular design choices in fvOptions made it
difficult to support MRF for multiphase and it is easier to support
frame-related and field related options separately.

Currently the MRF functionality provided supports only rotations but
the structure will be generalized to support other frame motions
including linear acceleration, SRF rotation and 6DoF which will be
run-time selectable.

twoPhaseEulerFoam: Update only the fixed-value phi patch fields before constructing the pressure eqn
Avoids small continuity error in parallel

twoPhaseEulerFoam: In the limit of phase-fraction->0 the velocity is calculated from a force balance

Rather than forcing the dispersed-phase velocity -> the continuous-phase
velocity as the phase-fraction -> 0 the velocity is now calculated from
a balance of pressure, buoyancy and drag forces.  The advantage is now
liquid or particles are not carried out of bubble-column of
fluidised-beds by the fictitious drag caused by forcing the
phase-velocities becoming equal in the limit.