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Light/Heating in tooth

Posted Oct 29, 2012, 10:28 a.m. EDT Version 4.2a 4 Replies

Benoit Queney
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Hi all! (Hi Ivar!)

I am currently trying to modelise the transformation of light into heat within a tooth. (You shine the tooth, and some light is transformed into heat by absorption)
I have succesfully succedeed to modelise that through absorption ans diffusion in the tooth, but my problem is to modelise the light coming on the tooth.
For the moment I have used a Dirichlet boundary condition saying I=Io on the surface, but it does not describe the propagation of the light through x and make the problem isotropic.
How would you modelise that incoming power propagating through x?

And I also have a second problem concerning the processing information. Indeed I need to know how much light has transformed intoheat, and so what I do is Heat= I in -Iout by doing an integration on the side of the tooth.
But it does not into account the reflexion/transmission, I would need only the transmitted power.
Any idea?

Cheers!
4 Replies Last Post Nov 8, 2012, 7:40 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Oct 30, 2012, 3:48 a.m. EDT
Hi

you could check the Model library "laser heating of a wafer", before there where also a model with a 2D-axi laser penetration calculation, then a 3D heating model based on the penetration results of the 2D axi, mapped into 3D, and superposed on the full model. This then aconted for the exp(-k*z) penetration depth based on the materials and layers

A general remark, when you make such "cubic" geometries, you could also, in the newer v4 versions make them directly by a block/rectangle, and a series of Layers (see the layer tab) even if you create some internal boundaries like that it's of little importance for the model complexity, and often the meshing goes quicker

--
Good luck
Ivar
Hi you could check the Model library "laser heating of a wafer", before there where also a model with a 2D-axi laser penetration calculation, then a 3D heating model based on the penetration results of the 2D axi, mapped into 3D, and superposed on the full model. This then aconted for the exp(-k*z) penetration depth based on the materials and layers A general remark, when you make such "cubic" geometries, you could also, in the newer v4 versions make them directly by a block/rectangle, and a series of Layers (see the layer tab) even if you create some internal boundaries like that it's of little importance for the model complexity, and often the meshing goes quicker -- Good luck Ivar
Benoit Queney
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Posted: 1 decade ago Oct 30, 2012, 5:16 a.m. EDT
Ok, thank you very much!
I just need to get the laser liscence now!
Thanks a lot,
Benoit
Ok, thank you very much! I just need to get the laser liscence now! Thanks a lot, Benoit
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Oct 30, 2012, 5:27 a.m. EDT
Hi

I cannot remmeber if its from the HT or the RF, but I would rather go for the Heat transfer module. Many older library models are not (yet) updated, so sometimes it's worth to ask your local rep if they have a model to illustrate a specific domain.

I believe there are some 500+ models in 4.3a but the COMSOL developpers must have several tousands at hand, I believe they have problems to update and check them quickly enough ;)

Do not forget the model gallery
Check this one www.comsol.eu/showroom/gallery/699/

--
Good luck
Ivar
Hi I cannot remmeber if its from the HT or the RF, but I would rather go for the Heat transfer module. Many older library models are not (yet) updated, so sometimes it's worth to ask your local rep if they have a model to illustrate a specific domain. I believe there are some 500+ models in 4.3a but the COMSOL developpers must have several tousands at hand, I believe they have problems to update and check them quickly enough ;) Do not forget the model gallery Check this one http://www.comsol.eu/showroom/gallery/699/ -- Good luck Ivar
Benoit Queney
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Posted: 1 decade ago Nov 8, 2012, 7:40 a.m. EST
Hi Ivar!
I'm still working on that model, andI would like to extract the amount of heat that has been dissipated (actually the percentage, but whatever), but I have not found a good method yet (For the moment I do a model with/without absorption and compare the integration of thepower on the sides of the tooth).

Any idea?

Thank you very much!
Hi Ivar! I'm still working on that model, andI would like to extract the amount of heat that has been dissipated (actually the percentage, but whatever), but I have not found a good method yet (For the moment I do a model with/without absorption and compare the integration of thepower on the sides of the tooth). Any idea? Thank you very much!

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