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Time dependent and non linear model takes (too?) long to solve...

Posted Jan 29, 2012, 5:52 p.m. EST Low-Frequency Electromagnetics, Geometry, Mesh, Modeling Tools & Definitions, Parameters, Variables, & Functions, Studies & Solvers Version 3.5a, Version 4.0, Version 4.0a, Version 4.1, Version 4.2, Version 4.2a 3 Replies

Norbert Bartscher
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Hello everyone,

I am simulating electrical machines within the rotating machinery interface in the ACDC module.

The model I calculate right now solves. But the way it solves is not satisfying in my oppinion. As soon as I choose the iron to be nonlinear, the solving takes days to calculate just 50ms with a time step of 100us.

I'm not sure if I'm allowed to upload the model in this forum, since the Geometry is not meant to be public.


The Geometry is a fourth of the motor and periodic boundary conditions are used for this. The current, stamped into the slots, is calculated by time dependent equations which involve the derivation of the flux field linkage. So comsol has to solve the equation for the current and vector potential simultaneously.


I already tried to improve the model this way:
www.comsol.com/support/knowledgebase/1127/
But it didn't really increase the speed. Actually with it's help the model could first be solved nonlinear...



Does anybody have general advices to get nonlinear time dependent models solved faster?


Thanks in advance.






3 Replies Last Post Jun 15, 2015, 9:14 p.m. EDT
Norbert Bartscher
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Posted: 1 decade ago Jan 29, 2012, 5:55 p.m. EST
By the way:

The mesh is only within the airgap very fine. All other domains use standard element size.
By the way: The mesh is only within the airgap very fine. All other domains use standard element size.
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Jan 30, 2012, 1:30 a.m. EST
Hi

have you also checked
www.comsol.eu/support/knowledgebase/1118/
www.comsol.eu/support/knowledgebase/1062/
www.comsol.eu/support/knowledgebase/905/

--
Good luck
Ivar
Hi have you also checked http://www.comsol.eu/support/knowledgebase/1118/ http://www.comsol.eu/support/knowledgebase/1062/ http://www.comsol.eu/support/knowledgebase/905/ -- Good luck Ivar
Omar Laldin
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Posted: 9 years ago Jun 15, 2015, 9:14 p.m. EDT
Hi Norbert,

I realize it has been a while since this thread was placed but I am now having issues similar to yours (rotating machinery, nonlinear steel, time-domain, resulting in *really* small time steps). Did you ever find a resolution? A couple of the links Ivar posted have also been deleted (I assume one of them led you to a good solution, hence the end of the thread).

Please let me know.

BR,
Omar
Hi Norbert, I realize it has been a while since this thread was placed but I am now having issues similar to yours (rotating machinery, nonlinear steel, time-domain, resulting in *really* small time steps). Did you ever find a resolution? A couple of the links Ivar posted have also been deleted (I assume one of them led you to a good solution, hence the end of the thread). Please let me know. BR, Omar

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