Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

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.

Modelling different time scale processes

Please login with a confirmed email address before reporting spam

Hello, I m trying to simulate an EKR process, I have flow of ions and need to model the water equilibrium for minimaly realistic results. I want to model water equilibrium as fast (instantaneus) equilibrim, I think I can do it writing expresions for the time derivatives of the H+ and OH- concentrations and resolve at the end of each step of the electromigration solver, but I can´t do it, ¿Is there anyway of say to comsol to solve migration, then equilibrium, the migration etc?.
I dont want to introduce the equilibrium condition togheter with migration cause I would nedd to introduce a great reaction rate and possibly use a small time step, whereas migration is a slow process.
I have read topics in this forum about reaction equilibrium questions that was not answered.
I know how to implement segregated solver and multistep solution procedure but still can't find the way or have encountered in the internet an example of how to do what I want, Im pretty desperated.
Any help of how to introduce water equilibrium in my simulation??
Also I have read about add a algebraic constraint to the concentrations, but Im not totally sure that this really captures the schtochiometry of the water equilibrium

0 Replies Last Post Oct 11, 2012, 2:18 p.m. EDT
COMSOL Moderator

Hello Francisco Angel

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.