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3D coil apply speed.

Posted 15 avr. 2018, 05:58 UTC−4 Electromagnetic Heating, Low-Frequency Electromagnetics Version 5.3 2 Replies

郊 刘
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I need to apply velocity to the coil in the 3D model. But the magnetic field (mf) module only has the Lorentz force velocity term in 2D/Axis symmetry, and the 3D model does not have this term. After that, I find that the magnetic field and electric field (mef) module can apply velocity in the 3D model. But the help documentation does not recommend this module to build the coil. A model I tried to do would give an error singular matrix. This consideration is implemented using a moving mesh. But this kind of method modeling is very troublesome, the simulation speed is too slow. Can I build a three-dimensional coil in magnetic and electric fields (mef)? Thank you very much.

2 Replies Last Post 16 avr. 2018, 23:35 UTC−4
Nirmal Paudel Tribhuvan University/Electrical Engineering
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Posted: 7 years ago 16 avr. 2018, 09:34 UTC−4

Hi,

You can certainly build 3D coils in MEF physics interface. However, you would need to understand the limitation of Velocity (Lorentz Term). Here is note from one of my blog post:

https://www.comsol.com/blogs/modeling-magnetic-bearings-in-comsol-multiphysics/

Note that the Velocity (Lorentz Term) feature can only be used when the moving domain does not contain prescribed magnetic sources like coils or permanent magnets that move along with the material. The moving domains must also be invariant in the direction of motion. For instance, the Velocity (Lorentz Term) feature can be used to model conductive homogeneous spinning disks. Some examples include magnetic brakes, an electrodynamic bearing, a homopolar generator, magnets over a moving infinite homogeneous plane (such as a falling magnet through a copper tube or maglev trains), and a flow of homogeneous conducting fluid past a magnet (such as liquid metal pumps or hall generators/thrusters).

Note: The Lorentz term accurately accounts for induction in a moving domain caused by stationary magnetic sources, provided the moving domain (including its material properties) does not change in the direction of motion. In addition, induction may be caused by temporal changes to either the strength of the stationary sources or a changing velocity. The Lorentz term does not incorporate the effect of such temporal changes.

If you have the above mentioned limitation, you would need to solve the model using Magnetic Fields and Moving Mesh. That is physically, including the translational motion of coil using the Moving Mesh interface.

Best Regards, Nirmal Paudel

Hi, You can certainly build 3D coils in MEF physics interface. However, you would need to understand the limitation of Velocity (Lorentz Term). Here is note from one of my blog post: https://www.comsol.com/blogs/modeling-magnetic-bearings-in-comsol-multiphysics/ -------------------------------- Note that the Velocity (Lorentz Term) feature can only be used when the moving domain does not contain prescribed magnetic sources like coils or permanent magnets that move along with the material. The moving domains must also be invariant in the direction of motion. For instance, the Velocity (Lorentz Term) feature can be used to model conductive homogeneous spinning disks. Some examples include magnetic brakes, an electrodynamic bearing, a homopolar generator, magnets over a moving infinite homogeneous plane (such as a falling magnet through a copper tube or maglev trains), and a flow of homogeneous conducting fluid past a magnet (such as liquid metal pumps or hall generators/thrusters). Note: The Lorentz term accurately accounts for induction in a moving domain caused by stationary magnetic sources, provided the moving domain (including its material properties) does not change in the direction of motion. In addition, induction may be caused by temporal changes to either the strength of the stationary sources or a changing velocity. The Lorentz term does not incorporate the effect of such temporal changes. --------------------------------- If you have the above mentioned limitation, you would need to solve the model using Magnetic Fields and Moving Mesh. That is physically, including the translational motion of coil using the Moving Mesh interface. Best Regards, Nirmal Paudel
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Posted: 7 years ago 16 avr. 2018, 23:35 UTC−4

Thank you very much. I understand that I should handle it with moving mesh.

Thank you very much. I understand that I should handle it with moving mesh.

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