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Exploiting symmetry in Eddy current model
Posted Dec 22, 2014, 6:53 p.m. EST Low-Frequency Electromagnetics, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 5.0 2 Replies
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Hi,
I am trying to reduce the geometry of an eddy current model using plane symmetries.
This model consists of:
1- A multiturn circular coil
2- An aluminium plate located underneath the coil
Im using the mf physics and a frequency domain study. I created a half model and a quarter model by defining the magnetic insulation boundary condition on symmetry planes ( both are attached ). basically, the coil resistance resulting from a quarter model should be half of the derived value from a half model but it seems they are not as predicetd. I'm only experiencing this problem for the value of resistance, in fact the imaginary part of impedance ( or voltage) is getting twice by changing a quarter model to a half model.
would you please tell me what the probable source of error is.
Thanks,
I am trying to reduce the geometry of an eddy current model using plane symmetries.
This model consists of:
1- A multiturn circular coil
2- An aluminium plate located underneath the coil
Im using the mf physics and a frequency domain study. I created a half model and a quarter model by defining the magnetic insulation boundary condition on symmetry planes ( both are attached ). basically, the coil resistance resulting from a quarter model should be half of the derived value from a half model but it seems they are not as predicetd. I'm only experiencing this problem for the value of resistance, in fact the imaginary part of impedance ( or voltage) is getting twice by changing a quarter model to a half model.
would you please tell me what the probable source of error is.
Thanks,
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2 Replies Last Post Jan 5, 2015, 10:23 a.m. EST
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Posted:
10 years ago
Hi,
The results that you are getting for Half Model and Quarter Models are correct. In COMSOL Multiphysics, you would have to manually account for this type of symmetry. That is, if you solve only a quarter model, your resistance of the coil (full model) will be 4 times the resistance of the quarter model. And this is true for voltage as well. Hope this helps.
Nirmal Paudel
The results that you are getting for Half Model and Quarter Models are correct. In COMSOL Multiphysics, you would have to manually account for this type of symmetry. That is, if you solve only a quarter model, your resistance of the coil (full model) will be 4 times the resistance of the quarter model. And this is true for voltage as well. Hope this helps.
Nirmal Paudel
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Posted:
10 years ago
Hi Dear Nirmal
Thanks for your response, I fully agree with the fact that I should multiply the resistance of the coil in quarter model by 4 in order to derive the resistance of a complete coil. In fact, the problem I am facing is that the value of resistance from a quarter model is equal to ( 206.70 Ohms) while the resulting value of resistance from a half model is (4299.2 Ohms) and this is completely wrong. This problem doesnt emerge for the inductance: the inductance of the coil for half model is 0.0879 H and the inductance for quarter model is 0.044 H which shows that the inductance for quarter model is half of the inductance for half model (its correct).
It should be noted, all the parameters such as frequency and conductivities are kept same and the geometry is divided correctly. I really appreciate it if you have the time to run the models (takes 2 mins tops) to compare the results and you may help me finding the probable error sources.
Regards,
Ehsan
Thanks for your response, I fully agree with the fact that I should multiply the resistance of the coil in quarter model by 4 in order to derive the resistance of a complete coil. In fact, the problem I am facing is that the value of resistance from a quarter model is equal to ( 206.70 Ohms) while the resulting value of resistance from a half model is (4299.2 Ohms) and this is completely wrong. This problem doesnt emerge for the inductance: the inductance of the coil for half model is 0.0879 H and the inductance for quarter model is 0.044 H which shows that the inductance for quarter model is half of the inductance for half model (its correct).
It should be noted, all the parameters such as frequency and conductivities are kept same and the geometry is divided correctly. I really appreciate it if you have the time to run the models (takes 2 mins tops) to compare the results and you may help me finding the probable error sources.
Regards,
Ehsan
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