Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

How to implement the Beer-Lambert absorption law when ablating a solid.

Please login with a confirmed email address before reporting spam

Hi,

I have a model which I am heating with a laser heat source.
The laser is absorbed in the solid according to Beer's law, that is the intensity of the radiation exponentially decays with path length, [ exp(-alpha*x) ] where x is path length.
This all works fine.

I am trying to implement albation in my model.
When the temperature goes above the vaporization temperature the material is 'ablated'.

My problem is that Beer's law scales with x so that it starts at x = 0 even when part of the material is ablated the equation still scales from x=0.

Basically I need to redefine my coordinate x as the ablated region moves across the material so that x starts at zero and increases linearly.

I have tried using a condition (T>300)*x where 300 is the vaporization temperature.
This condition works in that the x is zero up until the edge of the ablated region but then x jumps to whatever value it had before i.e it doesn't scale linearly.

If anyone has any information that might help me I'd really appreciate you letting me know.

Sorry if the explanation is extremely confusing!

Regards,
-Adam

1 Reply Last Post 15.04.2014, 11:12 GMT-4
COMSOL Moderator

Hello Adam Collins

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.


Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 15.04.2014, 11:12 GMT-4
Hi Adam,

i wonder if maybe you got your problem solved and if you still know the solution as well. In this case, could you please tell me what you have done? That would be awesome.

Regards
Steffen
Hi Adam, i wonder if maybe you got your problem solved and if you still know the solution as well. In this case, could you please tell me what you have done? That would be awesome. Regards Steffen

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.