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modeling of very thin layers
Posted Feb 18, 2011, 1:43 p.m. EST Heat Transfer & Phase Change Version 3.5a, Version 4.0a, Version 4.1 1 Reply
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Dear All,
I am studying the thermal behavior (heating, temperature distribution etc) of a magnetic iron block due to magnetic losses.
We can assume the the magnetic iron is a block (10mm x 20mm x 20 mm). In real life, this block is consisting of very thin layers of iron and insulating material :20 um iron, 5 um insulating material. These 25 um pairs are stacked on top of each other to reach the 10 mm height. In other words, the whole block consists of 20 um x 20 mm x 20 mm iron sheets with 5 um x 20 mm x 20 mm insulating sheets in between.
Obviously modeling the real geometry with individual layers loads the computer so heavily that even the GUI cannot handle the visualizaion, let alone the meshing and solving. (there are different parts in the model like windings, housing etc, in the mm range)
A practical approach would be of course modeling the whole block as one piece and using anistropic thermal conductivity. I believe an "equivalent thermal capacitance" can also be dereived using the individual specific heats of the iron and the insulating material. However, the losses occur only in the iron and not in the insulating material. So my question would be, basically, how to model to model this physical system.
Any ideas as well as literature recommendation is very welcome.
A further question would be, how to model different heat sources within one single iron layer, if for example the magnetic flux distribution in a layer is not equal and therefore non-uniform losses are produced within one iron layer.
Your inputs will be very much appreciated.
Arda
I am studying the thermal behavior (heating, temperature distribution etc) of a magnetic iron block due to magnetic losses.
We can assume the the magnetic iron is a block (10mm x 20mm x 20 mm). In real life, this block is consisting of very thin layers of iron and insulating material :20 um iron, 5 um insulating material. These 25 um pairs are stacked on top of each other to reach the 10 mm height. In other words, the whole block consists of 20 um x 20 mm x 20 mm iron sheets with 5 um x 20 mm x 20 mm insulating sheets in between.
Obviously modeling the real geometry with individual layers loads the computer so heavily that even the GUI cannot handle the visualizaion, let alone the meshing and solving. (there are different parts in the model like windings, housing etc, in the mm range)
A practical approach would be of course modeling the whole block as one piece and using anistropic thermal conductivity. I believe an "equivalent thermal capacitance" can also be dereived using the individual specific heats of the iron and the insulating material. However, the losses occur only in the iron and not in the insulating material. So my question would be, basically, how to model to model this physical system.
Any ideas as well as literature recommendation is very welcome.
A further question would be, how to model different heat sources within one single iron layer, if for example the magnetic flux distribution in a layer is not equal and therefore non-uniform losses are produced within one iron layer.
Your inputs will be very much appreciated.
Arda
1 Reply Last Post Feb 19, 2011, 3:46 p.m. EST
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Posted:
1 decade ago
Hi
you could try to model two layers with a "periodic boundary condition" (hence an infinite stack thickness) and probably derive from here som general properties, that you could then use as global properties for your bock as an anisotropic items thereafter
--
Good luck
Ivar
you could try to model two layers with a "periodic boundary condition" (hence an infinite stack thickness) and probably derive from here som general properties, that you could then use as global properties for your bock as an anisotropic items thereafter
--
Good luck
Ivar