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total heat transfer rate through wall and shadow not same

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Old   August 1, 2013, 02:08
Default total heat transfer rate through wall and shadow not same
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preetam
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hi,

in my simulation,the solution is converging really well.(i am solving a conjugate heat transfer problem)

but when i check the total heat transfer rate through the wall and the corresponding shadow wall,they are different(one almost half of the other).
shouldn't they be same? as both are actually same but one is shared by fluid and the other by the solid.(as far as my understanding)

can anyone point out what am i doing wrong over here?

thnx in advance.
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Old   August 5, 2013, 16:50
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miyage
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both of must be same. can you write values and assumption of simulation(about radiation - no radiation). maybe I can help you.
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Old   April 1, 2014, 07:39
Default Different Total Heat Transfer rate between wall and its shadow
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I am simulating a domain with a distributed heat source.
I calculate the corrispondent power I am injecting and compare it with the results I get.

Since I find I had different results I compare heat transfer rate between each wall and its shadow seeing that:
.for walls (positive heat flux):
if I sum all the heat transfer rate of the overall volume surface I do not get the overall power I am expecting to inject

.for shadows (negative heat flux):
if I sum all the heat transfer rate I get (with minus) the same power I am expecting to inject

This made me lead to see that for two walls (its an axisymmetric problem, the domain is a rectangle) the fluxes of wall and shadow wall are different

Does anybody found a similar problem?
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Old   October 2, 2017, 07:00
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Hi,

After 4 years, did anyone solve this issue? I am having the same problem. The main issue is with radiation. I am using DO radiation model and I have an internal solid mass(therefore 2 sided walls) in a combustion volume. Walls are opaque and their emissivity is 0.9. Unless my solid is semi-transparent and the solid zone participates in radiation, I always see different radiation heat transfer rates on different sides of the same wall.

Can anyone explain how this works please?

Thank you in advance,

Best regards,
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Old   November 25, 2021, 02:59
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Hi all,

Again after 4 years

Anyone can clarify the situation? I posted to ansys forum and still waiting.
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