Wall radiation modelling in OpenFOAM
 

Dear foamers,


Now I am studying coal combustion in a stagnation premixed CH4 flame. The P1 model is employed for radiation modelling. For the premixed CH4 flame, the results seems reasobale, but when I add coal particles into the stablized permixed flame. The G equation seems to diverge quickly(or not converge in 1000 iterations), and the calculated coal particle temperature is very low or high. which reason might contribute to this error? Any comments or suggestions are welcomed. The boundary for the incident radiation G is as following:
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object G;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [1 0 -3 0 0 0 0];

internalField uniform 0;

boundaryField
{
inlet
{
type MarshakRadiation;
T T;
emissivityMode lookup;
emissivity uniform 1.0;
value uniform 0;
}

wall
{
type MarshakRadiationFixedTemprature;
Trad uniform 600;
emissivityMode lookup;
emissivity uniform 1.0;
value uniform 0;
}
coflow
{
type MarshakRadiation;
T T;
emissivityMode lookup;
emissivity uniform 1.0;
value uniform 0;
}

outlet
{
type MarshakRadiation;
T T;
emissivityMode lookup;
emissivity uniform 1.0;
value uniform 0;
}

N2
{
type MarshakRadiation;
T T;
emissivityMode lookup;
emissivity uniform 1.0;
value uniform 0;
}

frontAndBack
{
type empty;
}

}