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Help regarding Laser Simulation and Time Step

Posted Apr 12, 2011, 1:34 p.m. EDT Heat Transfer & Phase Change 1 Reply

John Haase
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Hello,

I am extremely new to Comsol and so I apologize if my question is simplistic.

I am trying to model a laser beam with an even distribution in one direction and a Gaussian profile in the other. At the focal point the beam is 0.5mm x 12mm and the beam comes in at a 19 degree angle, the power of the laser is 4 kW. I want to be able to vary how far the focal point is from the surface of the object and the position where the beam is (not in the simulation just before I run it). Does anyone have a suggestion of how to model it so that I can vary these?

As well when I ran a model I had many time steps but all of the time steps looked identical (from 0.1 s - 10 s). Is there some option I have to change to see how the heat flow progresses?

Again I apologize for the probably simplistic questions.

Thank you for any assistance,

John
1 Reply Last Post Jun 9, 2011, 8:12 a.m. EDT
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Hello John Haase

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Sina Riecke
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Posted: 1 decade ago Jun 9, 2011, 8:12 a.m. EDT
Hi John,

I'm new to Comsol myself, but I believe I can answer part of your question.

I assume you want to use the laser beam as a heat source? In that case, just use the "volume heat source", and write the formula for your power distribution into the box at "user defined heat source". You can use x, y and z as your coordinates, and Comsol will recognize that.

Instead of using numbers in your formula, you can also use parameters, which you define in the "global definitions" (right click). Then you can vary them easily without changing your formula. You can even do automated parameter sweeps, but I don't know how to do that.

I also don't know about time dependence, I've only used the stationary study type.

Hope this helps!

Sina
Hi John, I'm new to Comsol myself, but I believe I can answer part of your question. I assume you want to use the laser beam as a heat source? In that case, just use the "volume heat source", and write the formula for your power distribution into the box at "user defined heat source". You can use x, y and z as your coordinates, and Comsol will recognize that. Instead of using numbers in your formula, you can also use parameters, which you define in the "global definitions" (right click). Then you can vary them easily without changing your formula. You can even do automated parameter sweeps, but I don't know how to do that. I also don't know about time dependence, I've only used the stationary study type. Hope this helps! Sina

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