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 The information provided may be out of date.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.

coupling variables

Please login with a confirmed email address before reporting spam

Hi

I am fearly new in COMSOL. I want to solve heterogenoeus chemical reactor models. I am struggling to couple the fluid phase with the solid phase. For example the 1D heterogeneous model:
Fluid phase:
-us*dC/dz=kg*av*(C-Cs)
us*rho*cp*dT/dz=hf*av*(Ts-T)-Ua*(T-Tw)

Solid phase:
De/r^2*d/dr(r^2*dCs/dr)=ra*rho
lamda_e/r^2*d/dr(r^2*dTs/dr)=-delH*ra

These are standard reactor design equations. I want solve the solid phase equations at every point along the length of the fluid phase equations. I have made the solid phase dimensionless (as in axample of spherically symmetric transport), so that you can only solve in one direction using general PDE, as it is spherical particle.

Can anyone help me to couple the solid phase to solve the concentration and temperature of the solid phase and then send that value to the fluid phase at every point along the length of the reactor(fluid) phase direction. I have tried coefficient form pde as well as weak form pde for fluid phase, not sure which will be best for this application.

I have tried to make two seperate models, for solid and fluid, but cant seem to get to couple the variabels, COMSOL cant detect the variable from other model.

Any suggestions in what strategy to follow?
(I hope i am posting in the right topic area)


0 Replies Last Post 2011年9月2日 GMT-4 05:03
COMSOL Moderator

Hello Francois Stander

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.