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 The information provided may be out of date.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.
general question about mass fractions/transport
Posted 23.06.2014, 16:54 GMT-4 Chemical Reaction Engineering, Materials, Studies & Solvers Version 4.3b 4 Replies
Please login with a confirmed email address before reporting spam
I have two reactors in contact with each other, both starting with the same initial conditions (equal amounts);
compound#1: solvent
Compund#2: A
compound#3: B
while in one of the reactors A is going to B and vice versa in the other reactor. I would assume that when I run the simulation, compounds A & B would diffuse ( the only physics added to the model being diffusion, no convection) and eventually reach a steady state. but when I run the simulation I get a negative mass fraction. how is that even possible?
Hello Aida Rouzmehr
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.
Please login with a confirmed email address before reporting spam
I met the same problem as you. Have you figured out it and what's the problem?
yuhong
Please login with a confirmed email address before reporting spam
Perhaps it would be easier to submit your model.
BR
Lasse
Please login with a confirmed email address before reporting spam
Thank u for your valuable time and thinking about my problem.
In fact, I am dealing with the module of transport of concentrated species with homogeneous initial mass fraction of 3 components. There is a mass flux boundary for two of these components without reactions. The other boundary conditions are either no flux or symmetry. When I run the transient simulation to study the concentrations change, it shows correct result at the beginning while it turns out the mass fraction of one component is larger than 1 and the one from mass constrait is negative.
Do you have any ideas about reasons for the errors?
Yuhong
Please login with a confirmed email address before reporting spam