Discussion Forum

Hi,

you need to model the geometries of rotor and stator separatly. There are many ways: eg with two DXFs. Both have a circle with the air gap radius (same value!). The in the final geometry operation you do a "Form Assembly".

Regards

Jens

Does you mean that the two DXF files need to have the same circle? White I imported the two files, will they override in comsol? Also, I tried importing the two files, but they don't have the same center, I must use the move order to make them in the same center? How can I make them automatically in the same center?

You might as well draw the circles that define the sliding surface in the air gap inside Comsol.

I think you should familiarise yourself with the "Form an Assembly" feature in the geometry first.

For example

c1=circle with radius=1 c2=circle with radius=2 substract c1 from c2 -> stator (ie a circular ring) c3=circle with radius=1 -> stator finalize with "Form an Assembly"

Then you should get the pair describing the air gap circle.

Once you have that you can add the details and unite (using "Union" feature) with the above stator and rotor.

Regards

Jens

Jens, Is that your mean In this way, can I make the shared boundaries automatically? So I need change my dxf file before I imported the file, now I what I need to do is to delete my air gap circle in the dxf. And import the file in comsol and draw the circle in comsol? I am afraid of misunderstanding your mean. Hope you can reply me soon.

Regards

Joey

(Almost) Nothing in this world happens automatically. You will need to draw the circle, be it in Comsol or your favourite DXF tool.

Have you done the simple exercise I wrote about? Once you understand pairs you can add the rest of the model from one or more DXF files.

Regards

Jens

Jens, I deleted all circles and tried drawing the circle you said, but it still cannot make the shared boundaries. Maybe I cannot understand 'pairs'? I still confused how to make the shared boundaries

Regards Joey

Dear Jens, Now I have another question. I am simulating a generator, I define the materials of different, I scan it in the material>>air. The air domains were covered the magnets. Does it for the CAD file I imported?

Joey, when did the simple example with the circles that I have desrcibed in my earlier post, did you sees the pair.

Also, did you check this one: https://www.comsol.com/model/generator-in-2d-2122

Regards

Jens

Jens, I tried drawing the circles you said, it successfully created the shared boundaries but not the boundaries I need. Now I have another question, while I defined the materials of different domains. In material>>air, I found the domains of magnet are covered by the air domain. The pic I uploaded is the correct definition of materials. You can see the pic in purple color that are domains of air. But in my model, I scanned the definition of the air domains, I found the purple color was covered the magnets. How can I avoid this poblem?