Configuration factors

[fsaero]

Hi guys, can you help me with a problem:

I have a cubic enclosure, 10cm length, and inside I have a cubic component (length 2cm) in the middle. I need to calculate the configuration factors for all surfaces ( or just one surface of the enclosure to all other surfaces). Each surface has to be taken as separate areas since they will be at different temperatures.

Any help is much appreciated. Thanks

 

[CH5OH]

since both enclosure and component are cubic and their size is known, the configuration is known.

 

[fsaero]

i would think so, but the problem is since the component is in the middle, wouldn't that account for some shielding from one enclosure surface to the next? Can you please give me a more specific answer please.

Many thanks

 

[CH5OH]

no problem, can you give a more specific question?
what do you mean by configuration factors?

 

[fsaero]

at the moment i am modelling the problem in 2-D so imagine just a square box of 10cm length with a solid 2cm box in the middle. MY problem is:
-one side of the box is subjected to solar intensity of approximately 1360W/m2
-the three other sides are kept at constant temperature of 3K
-the model is in space and therefore, a vacuum

Q: I want to find the equilibrium temperature of the component in the middle.

At the moment i know how to calculate the temperature, but I cannot input the numbers because my view(configuration) factor values are wrong. By view factor i mean the portion of radiation falling onto one surface from another.

 

[CH5OH]

I guess you mean the 5 other sides being held constant at 3k
so 1 side being heated through radiation
then the backside radiates as a result but there is also the way this heated panel is connected to the others
(conductivity)
may be as a start:

http://www.efunda.com/formulae/heat_transfer/radiation/overview_rad.cfm

 

[IRstuff]

If this is in space, then NONE of the surfaces are held at a fixed temperature; they might be VIEWING a 3K background.

You might try:

http://sourceforge.net/projects/view3d/

I haven't tried it myself, so no endorsements, one way or another. The geometry is relatively simplistic, and once you calculate the view factor for one surface, it'll be the same for the other 5.

TTFN

FAQ731-376

 

[fsaero]

thanks so much for the help guys, especially for the program, IRstuff. It is exactly what i need!