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heat transfer
Posted Nov 23, 2009, 5:32 a.m. EST 1 Reply
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Hello,
I have a angle wall only in concrete (thermal conductivity=2), one meter for each side of this wall. The interior temperature in 20°C and the exterior is 0°C. The interior transfer coefficient is h=7.69 and the exterior tranfer coefficient is h=25. The other boundaries are thermal insulation boundaries.
I have not the same heat flux between the interior and the exterior boundaries. Why??!!
And the two heat flux values are also changing with the meshing (the flux on the interior boundary is changing more sensibly than the "exterior flux"), Why??
Whereas I tested the same wall but in plan configuration (one meter of this plan wall) and I have the same flux between these boundaries (no variation with different meshing). So , in the last configuration, it is good.
Thanks for helping me on it.
I have a angle wall only in concrete (thermal conductivity=2), one meter for each side of this wall. The interior temperature in 20°C and the exterior is 0°C. The interior transfer coefficient is h=7.69 and the exterior tranfer coefficient is h=25. The other boundaries are thermal insulation boundaries.
I have not the same heat flux between the interior and the exterior boundaries. Why??!!
And the two heat flux values are also changing with the meshing (the flux on the interior boundary is changing more sensibly than the "exterior flux"), Why??
Whereas I tested the same wall but in plan configuration (one meter of this plan wall) and I have the same flux between these boundaries (no variation with different meshing). So , in the last configuration, it is good.
Thanks for helping me on it.
1 Reply Last Post Nov 23, 2009, 8:40 a.m. EST
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Posted:
2 decades ago
Hi
which version, which application mode? etc.
If you flg your "Subject" line with a [V3.5a-htgh] or something similar in the beginning it's already some more info that can help us to understand the environment, COMSOL is "rich" on different cases, and toolboxes.
Now, heat fluxes as any "gradient are somewhat "mesh dependent" when integrated over boundaries, you can use the "weak constraints" to getter better flux integrations, see the doc (search for weak constraints or "lm1")
And by the way, what are the order of magnitude of the differences ?
Good luck
Ivar
which version, which application mode? etc.
If you flg your "Subject" line with a [V3.5a-htgh] or something similar in the beginning it's already some more info that can help us to understand the environment, COMSOL is "rich" on different cases, and toolboxes.
Now, heat fluxes as any "gradient are somewhat "mesh dependent" when integrated over boundaries, you can use the "weak constraints" to getter better flux integrations, see the doc (search for weak constraints or "lm1")
And by the way, what are the order of magnitude of the differences ?
Good luck
Ivar