Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
Error "Repeated error test failures. May have reached a singularity" in a coupled analysis of eletric field, temperature and CFD
Posted Jul 5, 2018, 9:53 a.m. EDT Low-Frequency Electromagnetics, Heat Transfer & Phase Change, Computational Fluid Dynamics (CFD) 0 Replies
Please login with a confirmed email address before reporting spam
Dear all,
I have used Comsol version 4.4 for a coupled analysis of electrical field, temperature and fluid dynamic in a coaxial treatment chamber for liquid sterilization using pulsed electric field (PEF).
In a static condition (withou fluid flow), the model works fine, but when a fluid flow is considered, it is generated the error "Repeated error test failures. May have reached a singularity". I split the study in two steps: the first step from 0 to 0.11s is used to ramp up the fluid velocity. The inlet velocity is set to 20m/step(t[1/s]). A electrical pulse is applied in the second step (t=0.115s) with duration of 10us and magnitude of 24kV. I set the final solution of the first step as initial condition for the second step.I used a smoothing of 0.1s for the velocity step and 3us for electrical pulse. The temperature and fluid are coupled using the setting showed in the file attached.
When a laminar flow is used, the error is generated in the second step, but in this case the temperature increase is only 0,001 degC. When a turbulent flow is considered, the error appears in the first step.
The simulation using turbulent flow take more than 24 hours before generation of the error. I have tried to change some settings in the Comsol related to time stepping, boundary conditions and smoothing of the functions, but the problem was not solved.
It is attached also the mph file.
Best regards * Eduardo
Attachments:
Hello Eduardo Araujo
Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.
If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.