[theoOng]

Hi everyone,


I'd like to find out how fvDOM radiation multiBand settings work.


So far I've taken a look at the openfoam tutorial cases and i have not been able to find one with sufficient explanation on how to use the multiBandAbsorptionEmission model.




I know how to put in 5 entries into the absorption and emission coefficients:
I have put this in the code here:



solverFreq 10;
// means every 10 timesteps i solve 1 radiation equation


fvDOMCoeffs
{

nPhi 3;
nTheta 5;
tolerance 1e-3;
maxIter 10;


}



absorptionEmissionModel multiBandAbsorptionEmission;

multiBandAbsorptionEmissionCoeffs
{
absorptivity (0.5 0.5 0.5 0.5 0.5);
emissivity (0.5 0.5 0.5 0.5 0.5);
}




constantAbsorptionEmissionCoeffs
{
absorptivity absorptivity [ m^-1 ] 0.5;
emissivity emissivity [ m^-1 ] 0.5;
E E [ kg m^-1 s^-3 ] 0;
}


scatterModel none;

sootModel none;

However, as to which number corresponds to which band and wavelength, i haven't been able to find out so far.


I've taken a look in the source code:


https://www.openfoam.com/documentati...8C_source.html


and found that the band dependent parts go into this code:


(

4

*physicoChemical::sigma

*(aLambda_[0] - absorptionEmission_->aDisp(0)())

*blackBody_.deltaLambdaT(T_, absorptionEmission_->bands(0))

)


deltaLambdaT is found in blackbody emission


https://develop.openfoam.com/Develop...BodyEmission.C


And it shows that lambdaT is being interpolated from a table. However, where does one define lambda? And how does one define multiple bandwidths?



Greatly appreciate any help you guys can offer!


Best
Theo

[battiston]

Hello Theo,


I watch your videos in youtube about radiation, its very nice work!


Have you found answer for the question above?




att,
Battiston

[B_R_Khan]

Can anyone answer this?