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Modelling laser-heating of sample

Posted Jan 10, 2012, 5:34 a.m. EST Materials, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.1 8 Replies

Steven Cheung
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Hi,

I am a new user of the COMSOL package and I wish to try and simulate the heating of a spherical structure via a laser beam from one side. The first model I have created is simply a sphere with half of it having a boundary condition to simulate the laser beam but this is not entirely representative of the problem. The laser beam will be able penetrate the sphere and provide heating at certain depths and not just heating the surface of the sphere. In terms of dimensions, the laser beam is larger than the spherical structure.

I only have the basic Multiphysics module so will extra modules be required to solve my problem?

Thanks in advance.
8 Replies Last Post Jan 26, 2012, 10:06 a.m. EST
Edgar Kaiser
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Posted: 1 decade ago Jan 10, 2012, 6:48 a.m. EST
Hi Steven,

principally you can do everything with the basic module if you are willing to implement the equations of your model by yourself.
If you want to make your life easier and you are willing to spend the money then the heat transfer and the RF module might cover your physics.

Cheers
Edgar
Hi Steven, principally you can do everything with the basic module if you are willing to implement the equations of your model by yourself. If you want to make your life easier and you are willing to spend the money then the heat transfer and the RF module might cover your physics. Cheers Edgar
Steven Cheung
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Posted: 1 decade ago Jan 10, 2012, 7:03 a.m. EST
Thanks for the reply Edgar.

Something which I forgot to add and is rather crucial, is that the temperature jump which I wish to simulate is from 1.5K to 300K. In this temperature temperature range, a number of physical properties such as the specific heat capacity and thermal conductivity will change drastically so is COMSOL able to simulate these changes too?
Thanks for the reply Edgar. Something which I forgot to add and is rather crucial, is that the temperature jump which I wish to simulate is from 1.5K to 300K. In this temperature temperature range, a number of physical properties such as the specific heat capacity and thermal conductivity will change drastically so is COMSOL able to simulate these changes too?
Edgar Kaiser
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Posted: 1 decade ago Jan 10, 2012, 7:11 a.m. EST
Yes, all material properties can be defined as functions of temperature and any other variable. Of course it may not be trivial to really solve highly nonlinear models.

Cheers
Edgar
Yes, all material properties can be defined as functions of temperature and any other variable. Of course it may not be trivial to really solve highly nonlinear models. Cheers Edgar
Steven Cheung
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Posted: 1 decade ago Jan 11, 2012, 4:36 a.m. EST
Thanks Edgar, I'll give it a go.

Steven
Thanks Edgar, I'll give it a go. Steven
Steven Cheung
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Posted: 1 decade ago Jan 19, 2012, 7:35 a.m. EST
I've created an Interpolation table for my figures but not sure how to incorporate it into my model. The figures are for the specific heat capacity so I've created a user-defined property in my materials but not sure what to do next. My table (function name) is called SHC.

Furthermore, the headings in the table are t and f(t) suggesting a time and a function of time rather than temperature which is what I want, should I be concerned with this?
I've created an Interpolation table for my figures but not sure how to incorporate it into my model. The figures are for the specific heat capacity so I've created a user-defined property in my materials but not sure what to do next. My table (function name) is called SHC. Furthermore, the headings in the table are t and f(t) suggesting a time and a function of time rather than temperature which is what I want, should I be concerned with this?
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Jan 19, 2012, 8:18 a.m. EST
Hello

Why not load in a material with a T dependence and see how its done, that should give you the tips needed

--
Good luck
Ivar
Hello Why not load in a material with a T dependence and see how its done, that should give you the tips needed -- Good luck Ivar
Steven Cheung
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Posted: 1 decade ago Jan 26, 2012, 6:46 a.m. EST
Thank you for all the input so far, I appreciate it hugely.

I've managed to find a material that has a property variance in temperature but I can't seem to apply it to my model. The physics I am using is the coefficient form of a PDE but even though it appears I can assign the model with a material, when I assign the model with another material, I get the same result from the simulation.

Any suggestions?

Thanks.
Thank you for all the input so far, I appreciate it hugely. I've managed to find a material that has a property variance in temperature but I can't seem to apply it to my model. The physics I am using is the coefficient form of a PDE but even though it appears I can assign the model with a material, when I assign the model with another material, I get the same result from the simulation. Any suggestions? Thanks.
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Jan 26, 2012, 10:06 a.m. EST
Hi

have you checked the help about:

Variable Naming Convention and Scope

New Functionality in Version 4.2a

"New material container variable root.material simplifies access to material data. For example, "root.material.rho" is the density ρ as defined by the materials in each domain in the geometry. For plotting, you can type the expression material.rho to create a plot that shows the density of all materials."

--
Good luck
Ivar
Hi have you checked the help about: Variable Naming Convention and Scope New Functionality in Version 4.2a "New material container variable root.material simplifies access to material data. For example, "root.material.rho" is the density ρ as defined by the materials in each domain in the geometry. For plotting, you can type the expression material.rho to create a plot that shows the density of all materials." -- Good luck Ivar

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