How to deal with Conduction, Convection and radiation in OpenFOAM

This page is under construction. I will update by adding a description of each solver and model.

Conduction

laplacianFoam (Transient)

Convection

buoyantBoussinesqSimpleFoam (Steady)
buoyantBoussinesqPimpleFoam (Transient)
buoyantSimpleFoam (Steady)
buoyantPimpleFoam (Transient)

Conduction + Convection (Conjugate Heat Transfer)

chtMultiRegionSimpleFoam (Steady)
chtMultiRegionFoam (Transient)

+ Radiation

All the above solvers but laplacianFoam are able to deal with the radiative heat transfer. There are the following five (virtually four) models available in OpenFOAM. Their source code is located in src/thermophysicalModels/radiation/radiationModels and we can see the brief descriptions in the header file of each radiation class.

Class

Foam::radiation::P1

Description

Works well for combustion applications where optical thickness, tau is

large, i.e. tau = a*L > 3 (L = distance between objects)

Assumes

- all surfaces are diffuse

- tends to over predict radiative fluxes from sources/sinks

*** SOURCES NOT CURRENTLY INCLUDED ***

Keywords: optical thickness [2]

fvDOM (Finite Volume Discrete Ordinates Method)

Class

Foam::radiation::fvDOM

Description

Finite Volume Discrete Ordinates Method. Solves the RTE equation for n

directions in a participating media, not including scatter.

Available absorption models:

constantAbsorptionEmission

greyMeanAbsoprtionEmission

wideBandAbsorptionEmission

i.e. dictionary

\verbatim

fvDOMCoeffs

{

nPhi 4; // azimuthal angles in PI/2 on X-Y.

//(from Y to X)

nTheta 0; // polar angles in PI (from Z to X-Y plane)

convergence 1e-3; // convergence criteria for radiation

//iteration

maxIter 4; // maximum number of iterations

cacheDiv true; // cache the div of the RTE equation.

//NOTE: Caching div is "only" accurate if the upwind scheme is used

//in div(Ji,Ii_h)

}

solverFreq 1; // Number of flow iterations per radiation iteration

\endverbatim

The total number of solid angles is 4*nPhi*nTheta.

In 1D the direction of the rays is X (nPhi and nTheta are ignored)

In 2D the direction of the rays is on X-Y plane (only nPhi is considered)

In 3D (nPhi and nTheta are considered)

viewFactor

Class

Foam::radiation::viewFactor

Description

View factor radiation model. The system solved is: C q = b

where:

Cij = deltaij/Ej - (1/Ej - 1)Fij

q = heat flux

b = A eb - Ho

and:

eb = sigma*T^4

Ej = emissivity

Aij = deltaij - Fij

Fij = view factor matrix

opaqueSolid

Class

Foam::radiation::opaqueSolid

Description

Radiation for solid opaque solids - does nothing to energy equation source

terms (returns zeros) but creates absorptionEmissionModel and

scatterModel.

none

Class

Foam::radiation::noRadiation

Description

No radiation - does nothing to energy equation source terms

(returns zeros)

The settings of the radiation models are described in constant/radiationProperties file.

References

[1] Alexey Vdovin, Radiation heat transfer in OpenFOAM (PDF)
[2] Keith Grainge, Radiation Processes

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Author: fumiya

CFD engineer in Japan View all posts by fumiya

2 thoughts on “Conduction, convection and radiation in OpenFOAM (Under construction)”

Alberto Karkour says:

November 8, 2016 at 10:00 AM

Thanks! This is very helpful.

Aljanadi says:

May 31, 2020 at 9:23 PM

It gave me a general idea of what I will be studying

many thanks

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Author: fumiya

2 thoughts on “Conduction, convection and radiation in OpenFOAM (Under construction)”

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