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Thermal simulations: watt per second.

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Hello,

I have modelled an IC and I would like to set a block in my model (the IC) that produces a heat wave that is spread through the other components: PCB, solderballs, etc.

I am using the 'Heat transfer in solids' module. How can I set my boundary condition to increase the produced heat (power) of the IC block at 1 watt/second?

I have used time-dependent simulation and I have set my solver to the range 0-10 seconds, with step 1 second. But I cannot figure out how I can make it work... to increase the power of the IC.

Thank you alot beforehand

3 Replies Last Post Jul 31, 2015, 3:00 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 9 years ago Jul 22, 2015, 2:31 a.m. EDT
Hi

If I understand correctly you have a domain or boundary heat source, so if you want it to heat up more and more as a function of the time "t" you must enter a function depending on "t" in the filed for the heat source. Instead of i.e. 5[W] or 5[W/m^3] (depending on your options) choose 5[W/s]*t or better make a nice continuous analytical function under the Definition node i.e an1(t) and use that as source term.

In COMSOL (almost) each field can accept a scalar but also and just as well an equation !

--
Good luck
Ivar
Hi If I understand correctly you have a domain or boundary heat source, so if you want it to heat up more and more as a function of the time "t" you must enter a function depending on "t" in the filed for the heat source. Instead of i.e. 5[W] or 5[W/m^3] (depending on your options) choose 5[W/s]*t or better make a nice continuous analytical function under the Definition node i.e an1(t) and use that as source term. In COMSOL (almost) each field can accept a scalar but also and just as well an equation ! -- Good luck Ivar

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Posted: 9 years ago Jul 30, 2015, 3:10 a.m. EDT
Hello,

sorry for the late answer and thank you for the reply!

I will try to apply ypur solution.

Hello, sorry for the late answer and thank you for the reply! I will try to apply ypur solution.

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Posted: 9 years ago Jul 31, 2015, 3:00 a.m. EDT
Hello,

I tried to apply your solution and I have a question about it. In the equation 5[W/s]*t, the time will be taken from the step I define in the time-solver? E.g. from 0 to 10 sec, with step 1 second, or I have to define the time in a function?

Thank you very much beforehand.

Regards,

Dimitrios
Hello, I tried to apply your solution and I have a question about it. In the equation 5[W/s]*t, the time will be taken from the step I define in the time-solver? E.g. from 0 to 10 sec, with step 1 second, or I have to define the time in a function? Thank you very much beforehand. Regards, Dimitrios

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