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un-smooth output Heat Flux caused by solver oder BC?

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Hi All,

i'm having problem to get heat flux that comes out of PMSM smooth. A slice of PMSM produce loss evenly(BC Heat source) for example at winding (to simplify the problem, only on winding). Most of heat goes on water cooling that placed outside of stator. The heat flux (ntflux) is evaluated using surface intergral on outer boundary of stator.

it's a time dependent model and has about 1 million mesh (no warnings). All material properties are constant (non temperature-dependent).

On attached screen shots are the accumulated heat flux from all outer boundary divide by input of heat source. So the max. result should be 1.

to get the heat flux curve smooth i've tried to set the relative tolerance at 1e-8, using very small time step or "force" the solver time step as small as the result (strickt). And exclude algebraic.

Now i'm trying to change the solver setting and hope that the result be better. Every ideas are welcome.

best regards
Akmal



1 Reply Last Post 2014年5月23日 GMT-4 07:04

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Posted: 1 decade ago 2014年5月23日 GMT-4 07:04
Hi,

it solved using weak constrais on fixed temperature boundary, where heat flux is calculated.

www.comsol.de/support/knowledgebase/973/

regards
Hi, it solved using weak constrais on fixed temperature boundary, where heat flux is calculated. http://www.comsol.de/support/knowledgebase/973/ regards

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