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Problem Creating the "Air box"
Posted Apr 21, 2013, 10:54 p.m. EDT 1 Reply
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Hi everybody,
im new with comsol and im trying to simulate the magnetic flux density of a spiral inductor and the problem i have is that i cant create the air box correctly i think, been more specific y set the terminal and the ground of the spiral (solid geometry) and every think is ok, but when i add the air box and enclose my model the terminal and the ground boundaries says "not applicable" in the Magnetic and Electric Fields node. i would appreciate if you can explain me step by step what to do or what am i doing wrong.
Regards
im new with comsol and im trying to simulate the magnetic flux density of a spiral inductor and the problem i have is that i cant create the air box correctly i think, been more specific y set the terminal and the ground of the spiral (solid geometry) and every think is ok, but when i add the air box and enclose my model the terminal and the ground boundaries says "not applicable" in the Magnetic and Electric Fields node. i would appreciate if you can explain me step by step what to do or what am i doing wrong.
Regards
1 Reply Last Post Apr 22, 2013, 2:16 a.m. EDT
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Posted:
1 decade ago
Hi
ACDC in 3D require that you respect the Maxwell equations fully, that is that your current is running in a loop, you cannot have a current or voltage source (with current running) appearing in "thin air" in the middle of a model, and with the opposite current "sink" where the current disappears.
In reality when you apply current to a coil, you have two leads in/out, which also generate EM fields around them
The best is to loop the wires all out to the external boundaries (if you have coil wires) For multi-turn coil domains, there are a few tricks proposed by COMSOL, see i.e. the model library "inductor_3D" you need to add "sub nodes" (via right clicks) to the multi-turn physics domain node.
Check carefully the doc rather twice to understand the hypothesis used and the limitations implied.
Anyhow. if you are beginning with COMSOL, do first 2D-axi models, these are simpler to implement solve quicker and allow you to better understand the hypothesis, the way t set up and modify your model. 3D models are far heavier and take far more time to solve, hence to debug, and one gets easily frustrated. You will learn far quicker with 2D-axi, and then you can turn to 3D, far more efficiently
--
Good luck
Ivar
ACDC in 3D require that you respect the Maxwell equations fully, that is that your current is running in a loop, you cannot have a current or voltage source (with current running) appearing in "thin air" in the middle of a model, and with the opposite current "sink" where the current disappears.
In reality when you apply current to a coil, you have two leads in/out, which also generate EM fields around them
The best is to loop the wires all out to the external boundaries (if you have coil wires) For multi-turn coil domains, there are a few tricks proposed by COMSOL, see i.e. the model library "inductor_3D" you need to add "sub nodes" (via right clicks) to the multi-turn physics domain node.
Check carefully the doc rather twice to understand the hypothesis used and the limitations implied.
Anyhow. if you are beginning with COMSOL, do first 2D-axi models, these are simpler to implement solve quicker and allow you to better understand the hypothesis, the way t set up and modify your model. 3D models are far heavier and take far more time to solve, hence to debug, and one gets easily frustrated. You will learn far quicker with 2D-axi, and then you can turn to 3D, far more efficiently
--
Good luck
Ivar