LaEuScalarEmit

Syntax

Defined in couplingProperties dictionary.

forceModels
(
    LaEuScalarEmit
);
LaEuScalarEmitProps
{
    speciesNameDEM          word;
    rhoLiquid               scalar;
    velModelParam           scalar;
    denseRegimeVoidfraction scalar;     /optional/
    triggerFieldNameDEM     word;       /optional/
    triggerMinMax           (scalar scalar);    /optional/
    velFieldName            word;       /optional/
    fieldExplName           word;       /optional/
    fieldImplName           word;       /optional/
    fieldName               word;       /optional/
    speciesFieldName        wordList;   /optional/
    active                  switch;     /optional/
    scalarFieldNameCFD      word;       /legacy/
    scalarFieldNameDEM      word;       /legacy/
    partScalarFluxName      word;       /legacy/
    speciesFluxDEMIsMassBased Switch;   /legacy/
};

• speciesNameDEM = name of the scalar species in DEM, when using composition_properties in DEM. Please also make sure to use the same species name in CFD’s scalar transport equation.

• rhoLiquid = density of captured species

• velModelParam = model parameter to scale the explicit source term

• denseRegimeVoidfraction = (optional, default: 0.55) scalar value defining the threshold between dense and diluted collision regimes. If voidfraction < denseRegimeVoidfraction, the model is operating in dense regime, where no emission happens. If voidfraction > denseRegimeVoidfraction, the model is operating in dilute regime, where emission is calculated by below equations.

• triggerFieldNameDEM = (optional, needed if triggerMinMax is set) name of the DEM per-particle variable triggering the tracer transfer between the particle and the tracer concentration field. This keyword is read only if triggerMinMax is set by the user.

• triggerMinMax = (optional, default: (-INF, INF)) tuple defining the minimum and maximum values of the DEM variable named triggerFieldNameDEM in order to trigger the tracer transfer between particles and tracer concentration field. The exchange takes place only when the triggerFieldDEM > min(TriggerMinMax) and triggerFieldDEM < max(TriggerMinMax).

• velFieldName = (optional, default: U) name of vector field responsible for the advection of the tracer

• fieldExplName = (optional, default: scalarFieldNameCFD + “Source”) name of explicit source term field

• fieldImplName = (optional, default: scalarFieldNameCFD + “SourceKImpl”) name of implicit source term field

• fieldName = (optional, default: mLiquidTransfer ) species to pick-up spray mass to be transferred to DEM.

• speciesFieldName = (optional) list of species to pick-up spray mass to be transferred to DEM. if speciesFieldName is defined, fieldName will be ignored. Note that the mass of all species of this list will be transferred to one single DEM property via partScalarFluxName

• active = (optional, default: true) switch off the model, but keep necessary CFD-DEM communication propeties

• scalarFieldNameCFD = (legacy, use speciesNameDEM instead) name of the scalar field representing the tracer concentration

• scalarFieldNameDEM = (legacy, use speciesNameDEM instead) name of the DEM per-particle variable representing the amount of tracer carried by the particle (default: the same as scalarFieldNameCFD)

• partScalarFluxName = (legacy, use speciesNameDEM instead) name of the scalar field representing the tracer flux exchanged between the particles and the tracer concentration field

• speciesFluxDEMIsMassBased = (legacy, auto set for most models) this Switch specifies whether the species flux property transferred to DEM is considered to be mass, or volume based. Most DEM models such as liquidtransport/evaporation work based on mass. The DEM models liquidtransport/porous and liquidtransport/sponge require speciesFluxDEMIsMassBased to be set to false.

This forceModel reads the following forceSubModel switches and overwrites the defaults as indicated in parentheses:

• scaleDrag

• scaleDH

• verbose

Examples

forceModels
(
    LaEuScalarEmit
);
LaEuScalarEmitProps
{
    speciesNameDEM  "attrition";
    velModelParam       1e-9;
}

Description

Note

This forceModel does not influence the particles or the fluid flow.

This model emits a scalar property (e.g. attrition) from a particle to the fluid (e.g. attrition). The emission process takes place if a DEM property is within the specified bounds of triggerMinMax. This could model, for instance, emission taking place only for dry particles. The model distinguishes between two regimes based on the local voidfraction and the setting denseRegimeVoidfraction:

1. dense where no scalar property is emitted to the fluid and

2. dilute where the emitted volume is calculated as with being defined by velModelParam and the emitted volume additionally limited by the available scalar defined by scalarFieldNameDEM.

The solver then uses this source field in the scalar transport equation. A very similar implementation of this model can be found here: Goniva, C., Kloss, C., Chen, X., Donohue, T. J., & Katterfeld, A. (2014). Transfer chutes: Predicting dust emissions by multiphase CFD and coupled DEM-CFD simulations. Bulk Solids Handl, 34, 55-57.

Restrictions

None.

Related commands

forceModel