How to set different thermal conductivity in different direction?

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Xiang Qiu

Xiang Qiu

October 5, 2012 5:08am UTC

How to set different thermal conductivity in different direction?

I am trying to simulate a heat transfer model which includes layers with different thermal conductivity in X-Y direction and Z direction. Is it possible to assign a user defined material and have thermal conductivity as a vector? Any comments are appreciated.

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Ivar Kjelberg

Ivar Kjelberg

October 5, 2012 5:37am UTC in response to Xiang Qiu

Re: How to set different thermal conductivity in different direction?

Hi

yes
but you must define an anisotropic "k", or check the physics node and select anisotropic material, it depends slightly in which physics you are

By default isotropic material is choosen and the scalar "k" of the material is distributed on the diagonal of the tensor k11, k22, k33
Also in the latest 4.3 version "material.k" is not even defined, you must chose "material.k11" or sqrt(material.k11^2+ ..) or whatever suits youre model

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Good luck
Ivar

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Kamil Dursun

Kamil Dursun

January 5, 2013 3:15pm UTC in response to Ivar Kjelberg

Re: How to set different thermal conductivity in different direction?

Hello Ivar,
I have a similar question. I defined an anisotropic material in axi-symmetric 2 dimensions. What I get is a 2x2 array where I can fill in the values. However I am not sure which direction the k11, k12 etc. are.
I need to define one k for the r-direction and another for the z-direction.
I guess that k11 is the r-direction and k22 is the z-direction. Is this correct? What are k12 and k21 for?
Thank you for your reply.
Kamil

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Ivar Kjelberg

Ivar Kjelberg

January 6, 2013 9:28am UTC in response to Kamil Dursun

Re: How to set different thermal conductivity in different direction?

Hi

to check the orientation, load your initial values of your model, and add a plot more coordinate and get your directions.

in 3D you can use the Definition coordinates to define your given orientation, in 2D and 2D-axi also but you should also consider the symmetries you are adding by a 2D or a 2D axi which reduces the DoF available.

normally 11 is along the first coordiante, 22 along the second etc

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Good luck
Ivar

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