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.

Need help for microfluidic device simulation with high surface charge

Please login with a confirmed email address before reporting spam

Hello everyone,

I'm studying on a simulation of a conical nanopore with high surface charge density. In the physics, creeping flow, electrostatics and transport of diluted species are included. The model works perfectly and I get expected result with the surface charge density of -0.02C/m^2. Now I'm trying to increase the surface charge to -0.2C/m^2. By only changing the surface charge density, the model failed to get a result and said:

"Failed to find a solution for all parameters,
even when using the minimum parameter step.
No convergence, even when using the minimum damping factor.
Returned solution has not converged."

I thought it should be the mesh problem, so I changed to coarser mesh but failed again. The error said:

"Failed to find a solution.
Maximum number of Newton iterations reached.
There was an error message from the linear solver.
The relative error (0.098) is greater than the relative tolerance.
Returned solution is not converged."

I tried several solutions in the forum but still got stuck here. Is there any good suggestions to fix the problem?

Thank you so much,
Juntao

0 Replies Last Post 6 giu 2017, 14:18 GMT-4
COMSOL Moderator

Hello Juntao Dong

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.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.