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Electromagnet modeling in 3D BH curve&relative permeability
Posted 17 janv. 2013, 08:40 UTC−5 Low-Frequency Electromagnetics Version 4.0a 7 Replies
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at start let me say I am new in Comsol. I am using v 4.0a AC/DC Magnetic Fields. What I am trying to model is type of a magnetic brake. It`s geometry is very similar to plain electromagnet, consisting out of single cylindrical coil and a single (or mere) solid cylindrical iron (or other materials) solenoid. I have successfully modeled this geometry, defined all parameters and got results in 3D Plot Group 2/Slice 1/Arrow Volume 1/ etc. See attachment.
The thing that troubles me is how to define VARIABLE RELATIVE PERMEABILITY as a B-H curve function. i have modeled this geometry entering a number in relative permeability field but that is not want I want. I want to enter a r. permeability as a B&H curve function for specific material. I have data for B-H curves for materials of interest. I tried to type mu0*(normB/normH) as a equation in material`s relative permeability field and Comsol accepted this but I still do not see how or where to define B-H curve.
The main reason for doing this, correct me if I am wrong, is that I think I should enter relative permeability as a function not as a fixed number in case if I decide to make a solenoid out of two very different materials.
I know I haven`t presented my situation as best as it should, but I think You get the picture.
So, to summarize, should I enter relative permeability for certain material as a fixed number of as a B-H curve function and if so, how to do it?
Thank You all.
Hello Aleksandar Poznic
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I think I have the same problem of defining a variable relative permeability, how did you solve the problem?
Regards
Wanjiku
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4 Wanjiku:
I have not solve my "problem" jet. I putted comsol`s soft iron (with loses) instead my linear material. This soft iron has all B-H properties that You needs and You can just change existing parameters of it to suits You. It is that simple, :(.
On fortunately, after this I had problems with solvers. Now I do not have an idea how to overcome this problem.
I have realized that I can reduce my model to a simple model of a DC electromagnet with nonlinear material core.
Now I am looking for somebody's comsol 4.0a model of DC electromagnet so I can see where am I doing it wrong.
Best regards.
Sasa.
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I'm currently reviewing your query and installing COMSOL 4.2a. Unfortunately, I don't have a 4.0 version anymore, but I hope we still be able to solve your problem. If you would like to talk further, you can contact me on Skype: Rival-cs.
Kind regards,
Konstantin
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Not the 4.2.
You don have it saved somewhere.... long shot, I know.
No problem for Skype, aleksandarpoznic.
But I am not in a position to use it a next few day.
I don`t know how to read Your model. Your solution would be valuable to me.
Is there any chance to get a 4.0a model.....
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Anybody interested?
Please let me know at:
alpoznic@gmail.com