Elmer Discussion Forum

Hello,

I've been studying Elmer FEM through the webinars and tutorials to try to solve a problem, but still unsuccessful.

I'm trying a simple simulation of a reactor (core, coil and surrounding air). I used Freecad to design this reactor, using PART blocks. Later, I used the PART COMPOUND operation, because after reading the available documentation I understood that it would be the most appropriate when there are multiple objects. And finally, I made the meshes for each body and exported the .unv file.

My goal is to apply a value of current to the coil and check the magnetic flux in this reactor. For this, I am using CoilSolver in Elmer, as per the attached .sif file. However, I'm getting an error and I can't resolve it.

ERROR:: DefineCoilCenter: Coil has no volume!

Could you help me understand where the problem is and how to solve it?

Hi virnaco,

Your mesh looks quit inconsistent, i. e. the mesh of the core does not match with the mesh of the coil. Maybe try using Salome for the meshing. You can load your geometry, or start making it from scratch in Salome. Check out chapter 9 https://www.nic.funet.fi/index/elmer/do ... dElmer.pdf

HTH,

Felix

Hello Felix,

Thank you for the prompt answer! I'll try to follow your advice!

Best Regards,

Hi vinarco, I think that it was exactly what fff means.
I order to diagnose that there is a problem in your mesh, he checks the sif file. Can you please post your FreeCAD model?

Hello thalesmaoa,

Thank you for you reply!
Please find attached the Freecad file.

Hello Felix,

I've tried many times to use Freecad to design this reactor and mesh it, using different approaches (Boolean Fragments, Compound, etc), and it didn't work. I had the same error on Elmer:

ERROR:: DefineCoilCenter: Coil has no volume!

I agree with you that my mesh seem inconsistent.

As suggested by you, I started to use Salome. I used the step-by-step of that file (chapter 9) and the mesh now seems to be fine, but when importing UNV file to Elmer I had the same error: ERROR:: DefineCoilCenter: Coil has no volume!
I'm not sure if is there anything wrong importing the UNV file or with my HDF file...

Do you have an idea of what may be wrong?

According to equation 1 your coil is Body 2 yet in the component section you have it defined as body 1

Master Bodies(1) = Integer 1

if you change it to body 2

Master Bodies(1) = Integer 2

then all is well

Also I believe the coil normal is 0. 0. 1.

Hi kevinarden,

Thank you very much for your tip! It worked! The previously error disappeared. Another convergence error appeared, but I managed to get it right. I have attached the corrected SIF file for the record.

I'm new to Elmer and my goal is to simulate a transformer and then apply current transients to it. That's why I started with a simpler reactor. I've been studying the forums and watching Webnars, but I still have doubts about coilsolver. How to apply current to a given coil, coil normal, etc. I would appreciate it if you could send me links with information for me to study.