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Joules heating.

Posted 2012年6月19日 GMT-4 06:38 Heat Transfer & Phase Change, Mesh Version 4.3 1 Reply

Saikat Dutta
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Hello.
I have made a model of Primary terminal of a Transformer carrying a current of 300 A . I wanted to find out the heating in the Top chamber of the transformer where the terminal is connected. part of the terminal is immersed in Transformer Oil. and the rest is in Air. I have modeled a Joules heating coupled with Laminar flow. but while meshing I am getting an error . Please someone help me out with the error. The error states that "Could not shift boundary node at all" . Please help me on whats wrong with my model.
Thanks in Advance

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1 Reply Last Post 2013年6月6日 GMT-4 04:21
COMSOL Moderator

Hello Saikat Dutta

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Yoav Matia
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Posted: 1 decade ago 2013年6月6日 GMT-4 04:21
Hi there
here is the solution for you:

Prelude:
I to have encountered that same error so many times when i modeled 3D geometries yet almost never when modeling 2D geometries. Why?
COMSOL is trying to patch over the sharp corner diagonally in order to better/more smoothly mesh over the geometry in a way that will enable better representation of flow gradients over a corner.
all that is excellent and another reason why i have so much appreciation for COMSOL developers as they are actual Mathematics/Engineering/Physics professionals.
however, the problem is that doing this sort of "patching" is quite simple in 2D but very difficult in 3D, unless the geometry is very specific and of the kind that will not bring the meshing algorithm into collapse upon itself (due to impossible clustering of such elements).

(remainder: the higher the physics-gradient present at geometrical location, the denser the mesh you will need to "capture" and depict that phenomena using FEM, for reasons related to Element order).

Solution:
all you need to do is:
Ver 4.2a ==> uncheck the split boundary layer check box (see pictures attached)
Ver 4.3B==> choose the trimming option from the drop menu /Engineering

works for me every time :)
Hi there here is the solution for you: Prelude: I to have encountered that same error so many times when i modeled 3D geometries yet almost never when modeling 2D geometries. Why? COMSOL is trying to patch over the sharp corner diagonally in order to better/more smoothly mesh over the geometry in a way that will enable better representation of flow gradients over a corner. all that is excellent and another reason why i have so much appreciation for COMSOL developers as they are actual Mathematics/Engineering/Physics professionals. however, the problem is that doing this sort of "patching" is quite simple in 2D but very difficult in 3D, unless the geometry is very specific and of the kind that will not bring the meshing algorithm into collapse upon itself (due to impossible clustering of such elements). (remainder: the higher the physics-gradient present at geometrical location, the denser the mesh you will need to "capture" and depict that phenomena using FEM, for reasons related to Element order). Solution: all you need to do is: Ver 4.2a ==> uncheck the split boundary layer check box (see pictures attached) Ver 4.3B==> choose the trimming option from the drop menu /Engineering works for me every time :)

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