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Thermal Insulation Boundary Condition
Posted Jun 15, 2011, 2:09 p.m. EDT Heat Transfer & Phase Change 4 Replies
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Thermal Insulation is the default B.C. for heat transfer. I have tried adding "radiate-to-ambient", with known emissivity and ambient temperature, as a boundary condition to override this insulation. Despite my manually deselecting these boundaries, they always seem to reappear as insulated.
Your thoughts, please.
Your thoughts, please.
4 Replies Last Post Jun 16, 2011, 11:37 a.m. EDT
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Posted:
1 decade ago
Trying for a bump with more detail.
I have air moving through a duct, forced through a heat sink, and out another duct. All resting on a metallic.
I would like several outer boundaries, particularly of duct, heat sink, and base of to radiate-to-ambient. I do not wish them to have thermal insulation, but that seems to be a recurring default.
Thanks for your help.
I have air moving through a duct, forced through a heat sink, and out another duct. All resting on a metallic.
I would like several outer boundaries, particularly of duct, heat sink, and base of to radiate-to-ambient. I do not wish them to have thermal insulation, but that seems to be a recurring default.
Thanks for your help.
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Posted:
1 decade ago
Hi,
I am not sure I understand the problem. The defualt boundary condition is 'thermal insulation' in order to have something different that BC must be overridden, that is achieved by adding a different boundary condition and selecting that surface/edge/domain that must have a different boundary condition.
Cheers
I am not sure I understand the problem. The defualt boundary condition is 'thermal insulation' in order to have something different that BC must be overridden, that is achieved by adding a different boundary condition and selecting that surface/edge/domain that must have a different boundary condition.
Cheers
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Posted:
1 decade ago
I believe this is what I have done by selecting "radiate-to-ambient". I have one ambient temperature, and one surface emissivity for each radiating material.
These surfaces appear selected as "radiate-to-ambient", but also appear as insulated. When I de-select them in Thermal Insulation, they automatically revert to thermal insulation.
Should radiate-to-ambient not be an adequate boundary condition to override the default thermal insulation?
These surfaces appear selected as "radiate-to-ambient", but also appear as insulated. When I de-select them in Thermal Insulation, they automatically revert to thermal insulation.
Should radiate-to-ambient not be an adequate boundary condition to override the default thermal insulation?
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Posted:
1 decade ago
Hi,
If you add the 'Surface-to-Ambient Radiation' and select the desired boundary then in the default 'thermal insulation' boundary it still apears with a writing between parenthesis 'overridden' which means that thermal insulation does not apply any more.
Cheers
If you add the 'Surface-to-Ambient Radiation' and select the desired boundary then in the default 'thermal insulation' boundary it still apears with a writing between parenthesis 'overridden' which means that thermal insulation does not apply any more.
Cheers