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Using asphalt as a solar collector : divergence problem (new user)
Posted 07.04.2010, 04:30 GMT-4 1 Reply
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Dear Colleagues,
I am a new COMSOL user and I have some difficulties to make it work.
I explain myself : I am working on my Master Thesis now, and I am focusing on an asphalt collector system: by extracting the heat from the sun's radiation, by the mean of pipes with water flow installed in asphalt roads/pavements (thanks to its high thermal absorptivity)
In the model, representing a portion of asphalt with three pipes(with water), I'm using the general heat transfer module and the incompressible Navier-Stokes module.
The main interest, in my study,is the increase of the water temperature from the inlet to the outlet.
Whereas the system seems quite simple, I have some problems right now.
I got this kind of error message:
"Error:
Failed to find a solution:
Divergence of the linear iterations.
Returned solution has not converged."
I tried to : - change the inlet velocity
- use the time dependent solver instead
- improve the meshing
- set different boundaries
I also looked there :
www.comsol.com/support/knowledgebase/964/
But the error message is slightly different in my case.
It seems that the problem comes from the incompressible Navier-Stokes module.
It is my first project with COMSOL and I thought that this simulation was not very difficult to run, but now I am stuck because of my lack of experience with the software.
I would appreciate any help about how to proceed to make it converge.
Thank you very much in advance !
Kind regards,
Nicolas
I am a new COMSOL user and I have some difficulties to make it work.
I explain myself : I am working on my Master Thesis now, and I am focusing on an asphalt collector system: by extracting the heat from the sun's radiation, by the mean of pipes with water flow installed in asphalt roads/pavements (thanks to its high thermal absorptivity)
In the model, representing a portion of asphalt with three pipes(with water), I'm using the general heat transfer module and the incompressible Navier-Stokes module.
The main interest, in my study,is the increase of the water temperature from the inlet to the outlet.
Whereas the system seems quite simple, I have some problems right now.
I got this kind of error message:
"Error:
Failed to find a solution:
Divergence of the linear iterations.
Returned solution has not converged."
I tried to : - change the inlet velocity
- use the time dependent solver instead
- improve the meshing
- set different boundaries
I also looked there :
www.comsol.com/support/knowledgebase/964/
But the error message is slightly different in my case.
It seems that the problem comes from the incompressible Navier-Stokes module.
It is my first project with COMSOL and I thought that this simulation was not very difficult to run, but now I am stuck because of my lack of experience with the software.
I would appreciate any help about how to proceed to make it converge.
Thank you very much in advance !
Kind regards,
Nicolas
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1 Reply Last Post 08.04.2010, 02:15 GMT-4
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Posted:
1 decade ago
Hi Nicolas,
nice to hear that other folks work on our solar future, too. :)
I try to build a solar cell model with comsol. I am not able to
open your model (i have no licence for the heat stuff) and my
semiconductor model has nothing to do with your model,
but you may play around with following:
-Try to start with a simple case for which you know an analytic solution
and where you expect low gradients in the solution.
After you are sure your boundary settings are ok you
can try to increase the challenge.
-If you are using the stationary solver, you might select the
"Highly nonlinear problem" check box or tune the damping parameters
manually.
-You might also try to change the maximum number of iterations.
-The Stationary segregated solver might help as well: Create a group
for each variable you solve for.
Good luck!
nice to hear that other folks work on our solar future, too. :)
I try to build a solar cell model with comsol. I am not able to
open your model (i have no licence for the heat stuff) and my
semiconductor model has nothing to do with your model,
but you may play around with following:
-Try to start with a simple case for which you know an analytic solution
and where you expect low gradients in the solution.
After you are sure your boundary settings are ok you
can try to increase the challenge.
-If you are using the stationary solver, you might select the
"Highly nonlinear problem" check box or tune the damping parameters
manually.
-You might also try to change the maximum number of iterations.
-The Stationary segregated solver might help as well: Create a group
for each variable you solve for.
Good luck!