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-   -   greyMeanAbsorptionEmission (http://www.cfd-online.com/Forums/openfoam-solving/71933-greymeanabsorptionemission.html)

mange January 20, 2010 07:50

greyMeanAbsorptionEmission
 
Hi,

I have added the radiation module into reactingFoam and it seems to work fine.
My question now is how to use "greyMeanAbsorptionEmission" so that I can have absorption and emmission coefficients as a function of , say, CO2 massfraction.
As I understand the calculated species massfraction will be used since i am solving for CO2. Therfore I can give polynomial coefficients in a greyMeanAbsorptionEmissionCoeffs sub dictionary.
There seems also to be an option of defining the coefficients in a lookuptable . I do so far not have intentions of using this table but it seems that it must exist in order to use the class. The table should be located under constant/ and if it does not exist the solver exits with a fatal error
I have studied the source for the class but I run into trouble with the interpolationLookUpTable and cannot figure out what format the input file should be.

I think it should be of class dictionary, and it has to contain the keywords fields, output and value. But everything I try just fails :(

Anyone has an idea about this??

mange January 21, 2010 04:19

By the way I am using 1.6.x .

Any suggestions or hints would be highly welcomed.
Did anyone use this model before?

mange January 26, 2010 09:27

Hi again,

I managed to find a working format, which looks like this:

fields
1
(
{
N 1;
max 1.0;
min 0.0;
name apa;
}

)
;
output
1
(
{
name apa;
}
)
;
values
2
(
(0 0.0)
(1 0.0)
)
;

I am still very confused of what this does. But I am solving for the species of interest so I hope it does not influence anyhow. I also had to create a volScalarField called "ft" for it to work and "ft" needs to be registered with the other species and appearently solved for as well. well I just put it to zero in the entire field.

I now managed to get the absorptioncoefficient as a function of CO2. But I do not know if I can trust the results since I have the feeling that i have misunderstood something important here.

Could anyone shed some lights on this?

shajitah September 11, 2010 20:26

Hi Magnus,

I have encountered the same problem right now. I was wondering if you so far has fixed the problem, and give some info of how to define the SpeciesTable dictionary. By the way, I've also sent you a private message with more details.

Thanks
Sina

Bufacchi September 15, 2010 16:47

Guys,

Please take a look at fireFoam. It uses exactly what you are looking for, although there is no white paper explaining the code.

Regards,

Paulo
:)

Marshak May 2, 2012 08:49

Can anyone explain the code for 'SpeciesTable' in case of grey mean absorption model used ?


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