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Thermal tuning frequency response
Posted Mar 29, 2012, 1:02 p.m. EDT Version 4.2a 1 Reply
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Hi guys,
Wondered whether anybody had any thoughts on my problem.
I am trying to find the frequency response of my system to thermal tuning.
Basically I heat my model with a boundary layer heat source in the structural mechanics->thermal heating module. I would like to find out what the highest frequency of heating the system temperture can respond to before its smudged out.
I can input a sinusoidally varying heat source and look at the resulting temperature v time plot however this is slow if I have to do it for multiple frequencies (although I could do a parameter sweep)
Does anyone know if can use the frequency domain study (I can see no option in heat transfer to add a harmonic perturbation) to get a frequency v amplitude graph?
Cheers
Peter
Wondered whether anybody had any thoughts on my problem.
I am trying to find the frequency response of my system to thermal tuning.
Basically I heat my model with a boundary layer heat source in the structural mechanics->thermal heating module. I would like to find out what the highest frequency of heating the system temperture can respond to before its smudged out.
I can input a sinusoidally varying heat source and look at the resulting temperature v time plot however this is slow if I have to do it for multiple frequencies (although I could do a parameter sweep)
Does anyone know if can use the frequency domain study (I can see no option in heat transfer to add a harmonic perturbation) to get a frequency v amplitude graph?
Cheers
Peter
1 Reply Last Post Mar 29, 2012, 4:34 p.m. EDT
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Posted:
1 decade ago
Hi
what about taking some time to look at the analytical solution from a HT text book.
From your material data you know k, Cp and rho hence the heat diffusivity alpha = k/rho/Cp [m^2/s] then one can state that the pentration depth is roughly Dz=sqrt(4*alpha*Dt) where Dt is your frequency period
The global result depends somewhat on your geometry shape and dimension ratios but this is basically the maximum depth you will observe any small oscillation, above it will be just the average temperature that might change
Test it out on an elongated bar in i.e. Aluminium, fix the temperature on one side, add a boundary sinus heat load on the other side, use a boundary layer mesh on the heat source side to catch better the gradient, and perform a time sweep over 2 periodse
--
Good luck
Ivar
what about taking some time to look at the analytical solution from a HT text book.
From your material data you know k, Cp and rho hence the heat diffusivity alpha = k/rho/Cp [m^2/s] then one can state that the pentration depth is roughly Dz=sqrt(4*alpha*Dt) where Dt is your frequency period
The global result depends somewhat on your geometry shape and dimension ratios but this is basically the maximum depth you will observe any small oscillation, above it will be just the average temperature that might change
Test it out on an elongated bar in i.e. Aluminium, fix the temperature on one side, add a boundary sinus heat load on the other side, use a boundary layer mesh on the heat source side to catch better the gradient, and perform a time sweep over 2 periodse
--
Good luck
Ivar