# OpenFOAM® v1612+: New solver and physical models

23/12/2016

## New Eddy Dissipation Model (EDM) combustion model

A new turbulent diffusion combustion model named eddyDissipationDiffusionModel based on the principle of mixed is burnt has been implemented. The time scale is determined by the minimum of the turbulence and diffusion time scales.

The reaction rate is given by

Where , , and designate the mass density, fuel and oxygen mass fraction, and the stoichiometric oxygen-to-fuel mass ratio. The turbulence mixing time scale is taken from the turbulence model, in the case of the - model:

where is the turbulence kinetic energy and the eddy dissipation rate. In the laminar region, fuel-air mixing is controlled by molecular diffusion:

where .

The EDM combustion model is derived from the singleStepReaction model, hence the mixture for the thermoType will be singleStepReactingMixture. The stoichiometric equation together with the list of species is prescribed in the $FOAM_CASE/constant/reactions file. The following image shows the new model being applied to the compartmentFire tutorial case: Model settings, e.g. for the model constants Cd and CEDC are entered in the file$FOAM_CASE/constant/combustionProperties

combustionModel eddyDissipationDiffusionModel<psiThermoCombustion,gasHThermoPhysics>;

active          on;

eddyDissipationDiffusionModelCoeffs
{
semiImplicit    false;
CEDC            4;
Cd              4;
}

Source code
$FOAM_SRC/combustionModels/eddyDissipationDiffusionModel$FOAM_SRC/combustionModels/eddyDissipationModelBase
Examples

## New Lagrangian injection models

The following example shows the results of a Lagrangian case whose particles are seeded using the output from the new extractEulerianParticles function object, where each Lagrangian particle is equivalent to a single Eulerian fluid element.

Source code
$FOAM_SRC/lagrangian/intermediate/submodels/Kinematic/InjectionModel/InjectedParticleInjection$FOAM_SRC/lagrangian/intermediate/submodels/Kinematic/InjectionModel/InjectedParticleDistributionInjection
Examples
$FOAM_TUTORIALS/multiphase/interFoam/laminar/vofToLagrangian/lagrangianParticleInjection$FOAM_TUTORIALS/multiphase/interFoam/laminar/vofToLagrangian/lagrangianDistributionInjection

## New scalar transport functionality

$FOAM_SRC/functionObjects/solvers/scalarTransport Residence time example$FOAM_TUTORIALS/incompressible/pimpleFoam/RAS/TJunction
$FOAM_TUTORIALS/multiphase/interFoam/RAS/angledDuct Phase constrained transport$FOAM_TUTORIALS/multiphase/interFoam/RAS/waterChannel