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mandar September 16, 2008 02:48

S2S model
 
hello sir,

i have some problems about radiation modelling in S2S:

here is some description of problem :: square 2D cavity bottom hot top cold side walls adiabatic

i am using S2s model but i see that it is not giving correct results for the low emissivities

e.g.top bottom 0.5 and side walls 0.1

Radiation Heat Transfer Rate (w) -------------------------------- --------------------

bottom 0.22598088

left 0.00022241924

right 0.00030250785

top 0.12082574

---------------- --------------------

Net 0.34733155

but it gives accurate results if i keep e=1 for all (for checking this i have kept gravity=0 and k =0 for air so that i get only radiative heat transfer)

one more absurd thing is that if i keep one of the top or bottom e=0 it gives like :

Radiation Heat Transfer Rate (w) -------------------------------- --------------------

bottom 0

left 0.00020713897

right 0.00024958443

top 0.017235142

---------------- --------------------

Net 0.017691865

which actually should be close to 0.

this is what i find problematic

maximum iterations exceeded in radiation calculations. Radiosity unconverged after 5 iterations Final radiosity residual = 2.983e-003

can you please guide me regarding this ?

(emissivity i give in the internal emissivity)

waiting for reply

mandar


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