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Calculating heat leaing into system
Posted Jun 28, 2016, 9:31 a.m. EDT Heat Transfer & Phase Change Version 4.4 1 Reply
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I have a system which contains liquid nitrogen surrounded by isolating material and I want to calculate the heat leaking into the stystem.
- I build my stystem with the appropiate thermal conductivities
- Simulated the contact with the surrounding air using the "convective Heat flux" boudary condition
- And gave the nitrogen a temperature of 77K using the "temperature" boudary condition
I compute using a "Stationary" study step and afterwards I try to calculate the heat leakage using a surface integration of the flux over the outside of my system (using expression ht.tfluxMag).
However the result from this integration is not what I would expect. It seems to depend on the surface I chose to integrate over (my isolation consists of different layers). This is strange since the heat leaking into the outer boundaries of my system should be equal to the heat leaking into the nitrogen itself?
Does anybody know what goes wrong?
I am new to COMSOL, so any tip may be helpfull!
Thank you!
- I build my stystem with the appropiate thermal conductivities
- Simulated the contact with the surrounding air using the "convective Heat flux" boudary condition
- And gave the nitrogen a temperature of 77K using the "temperature" boudary condition
I compute using a "Stationary" study step and afterwards I try to calculate the heat leakage using a surface integration of the flux over the outside of my system (using expression ht.tfluxMag).
However the result from this integration is not what I would expect. It seems to depend on the surface I chose to integrate over (my isolation consists of different layers). This is strange since the heat leaking into the outer boundaries of my system should be equal to the heat leaking into the nitrogen itself?
Does anybody know what goes wrong?
I am new to COMSOL, so any tip may be helpfull!
Thank you!
1 Reply Last Post Jul 1, 2016, 7:21 a.m. EDT
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Posted:
8 years ago
HI Bumblebee...
I suggest you address your post directly to: support@comsol.com
Best,
François Mandias
I suggest you address your post directly to: support@comsol.com
Best,
François Mandias