Radiation solid

Sas · June 23, 2010, 10:46

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, 19:42

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, 11:42

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, 19:45

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, 07:12

Quote:

Originally Posted by ghorrocks

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, 07:36

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, 10:15

Quote:

Originally Posted by ghorrocks

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, 08:40

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.

June 23, 2010, 10:46	Radiation solid	#1
Sas New Member Join Date: May 2010 Posts: 21 Rep Power: 16	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

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June 23, 2010, 19:42		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,850 Rep Power: 144	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.

June 24, 2010, 11:42		#3
Sas New Member Join Date: May 2010 Posts: 21 Rep Power: 16	I use the discrete transfer. Help who knows what adsorption coefficient and scattering coefficient for hard material (clinker/cement concrete/sand).

June 24, 2010, 19:45		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,850 Rep Power: 144	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.

June 25, 2010, 07:36		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,850 Rep Power: 144	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.

June 26, 2010, 08:40		#8
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,850 Rep Power: 144	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.