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-   -   Radiation solid (http://www.cfd-online.com/Forums/cfx/77455-radiation-solid.html)

Sas June 23, 2010 09:46

Radiation solid
 
Prompt as смоделировать radiation from solid domen to fluid.
Has used the model Monte Carlo but is not seen radiations from lower to upper.
Can not understand why.

http://imagepost.ru/?v=161/Heat_transfer_001.png

ghorrocks June 23, 2010 18:42

Do you need the Monte Carlo approach? Will the discrete transfer approach work for you? It is much simpler and far easier to get good results with, as long as transmittion/path effects are not significant.

Sas June 24, 2010 10:42

I use the discrete transfer.

Help who knows what adsorption coefficient and scattering coefficient for hard material (clinker/cement concrete/sand).

ghorrocks June 24, 2010 18:45

These values vary a lot. Best if you get the data for your specific material. Otherwise a google search should be able to find some representative numbers.

Sas June 25, 2010 06:12

Quote:

Originally Posted by ghorrocks (Post 264436)
These values vary a lot. Best if you get the data for your specific material. Otherwise a google search should be able to find some representative numbers.

I searched on the internet, I can not find, I would know about for any solid to material are to be seen, these coefficients (in CFX uses linear coefficients with the dimension m ^ -1).

ghorrocks June 25, 2010 06:36

Well if you are looking for web values then don't expect them to be even remotely accurate. Might as well just guess. I would guess that all those materials would have a high adsorption coefficient (0.9) and a low scattering coefficient (0.1). But these values are nothing but total guesses. If you can't find real values you should do a sensitivity study on them - the exact value probably does not make any difference anyway.

Sas June 25, 2010 09:15

Quote:

Originally Posted by ghorrocks (Post 264491)
Well if you are looking for web values then don't expect them to be even remotely accurate. Might as well just guess. I would guess that all those materials would have a high adsorption coefficient (0.9) and a low scattering coefficient (0.1). But these values are nothing but total guesses. If you can't find real values you should do a sensitivity study on them - the exact value probably does not make any difference anyway.

Thanks a lot!

CFX only requires these factors dimension m^-1. Is it possible to do something translated from a fraction of units (0,9 and 0,1) to m^-1?

ghorrocks June 26, 2010 07:40

Oh yes, sorry - my previous post was wrong. The properties you refer to are the absorption and scattering of radiation inside the material. If you are using this solid material for particle tracking there is no radiation modelling inside the particle so these properties are not used. Just give them a value of zero.

These properties are only used for solid domains - if you have a solid domain of this material you better make something up.


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