Convergence problem

Please login with a confirmed email address before reporting spam

Hello,

I have a Comsol license within the company Framatome. I am currently working on a topic related to the simulation of fluid flow within a test loop section (inlet d = 3mm + rack + 4 titanium steam generator tubes with a diameter of 17mm) and I am encountering a problem with the simulation.

The chosen physics:

Laminar flow (Re = 9 / Velocity = 2.36 * 1E-03)

Steady-state study (solver, tolerance, error; all left as default)

Mesh: Normal (Defined by the physics)

Temperature: 25°C

However, in the end, the solution does not converge, displaying the following message: "Failed to find a solution. Divergence in the iterations of the linear solver. The linear solver/preconditioner is ill-conditioned. The relative residual is more than 1000 times larger than the tolerance. The returned solution did not converge properly."

I would greatly appreciate any clarification regarding this type of error and a possible solution.

Best regards,


3 Replies Last Post Apr 18, 2025, 8:05 p.m. EDT

Please login with a confirmed email address before reporting spam

Posted: 3 days ago Apr 16, 2025, 11:41 a.m. EDT

It is almost always impossible to make suggestions without seeing the (reduced) mph file.

However 3D laminar flow problems usually require a pressure point constraint for convergence.

It is almost always impossible to make suggestions without seeing the (reduced) mph file. However 3D laminar flow problems usually require a pressure point constraint for convergence.

Please login with a confirmed email address before reporting spam

Posted: 2 days ago Apr 17, 2025, 9:00 a.m. EDT
Updated: 2 days ago Apr 17, 2025, 9:00 a.m. EDT

Hello David , Thank u in advance for the reply Conserving all the paramaters that i published before this is the mph file (geometry ) Notice the version is little bit old 4.4

Hello David , Thank u in advance for the reply Conserving all the paramaters that i published before this is the mph file (geometry ) Notice the version is little bit old 4.4


Please login with a confirmed email address before reporting spam

Posted: 13 hours ago Apr 18, 2025, 8:05 p.m. EDT

4.4 is very old and it is unlikely that anyone can open a file.

By the way .mphbin is not a reduced file, see the instructions at the bottom of this page.

4.4 is very old and it is unlikely that anyone can open a file. By the way .mphbin is not a reduced file, see the instructions at the bottom of this page.

Reply

Please read the discussion forum rules before posting.

Please log in to post a reply.

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.