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.

Transport of concentrated species, Membrane gas separation

Please login with a confirmed email address before reporting spam

I've attached simplified model describing transport of the one component through membrane. I've made it simple to make you catch a problem easily. In my advanced model I'm using Laminar Flow physics and 2D axissymmetry as well.
The problem is with mass balance in this scheme - see Line Graphs. As a result it gives mass/mole fractions higher than 1 or lower than 0. Likely I don't get some sense of using Transport of concentrated species interface.
How can I make all of the components passing the membrane? As I'm choosing 3 components, I can define flux only for 2.
What happens on the feed side when part of the component is leaving by the wall? I think the pressure should decrease along the wall (according to decreasing of component partial pressure and friction influence on fluid flow), also mass flux decreases. Does Comsol "knows" that?
Are the Laminar flow and Transport of concentrated species interfaces sufficient to create property model in this case?

I wish you know the answers ;-)
I'm beginner - I'm sure you've guessed.

Anna


9 Replies Last Post 2016年10月29日 GMT-4 08:59

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2013年4月12日 GMT-4 08:15
There is undesirable minus in front of the equation describing inward flux in chcs2. Anyway problem still appears.
There is undesirable minus in front of the equation describing inward flux in chcs2. Anyway problem still appears.

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2013年4月17日 GMT-4 18:42
Hey!

I have faced the same problem you have. I got around it by adding an extra inert species (water in my case) which does not cross the membrane. You can then choose to solve the mass fraction of your inert species with the mass constraint and you can flux all the other species across the membrane.

Sri.

P.S.: I am a beginner too.
Hey! I have faced the same problem you have. I got around it by adding an extra inert species (water in my case) which does not cross the membrane. You can then choose to solve the mass fraction of your inert species with the mass constraint and you can flux all the other species across the membrane. Sri. P.S.: I am a beginner too.

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2013年4月20日 GMT-4 14:19
Thanks for reply.
However, I'm gonna ask for help some Comsol expert (still looking for somebody), because I don't feel like I can manage it only by myself.
I have a problem with a mass balance when using Transport of concentrated species, probably other conditions need to be defined...
Thanks for reply. However, I'm gonna ask for help some Comsol expert (still looking for somebody), because I don't feel like I can manage it only by myself. I have a problem with a mass balance when using Transport of concentrated species, probably other conditions need to be defined...

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2013年4月29日 GMT-4 09:02
I have just found very interesting explanation how to use Transport of Concentrated Species physics when coupled with Laminar Flow. The article clarifies a lot for me.
www.comsol.com/support/knowledgebase/1100/

The problem is I can not open the file. If anyone can convert it to 4.3 or 4.3a version file, please do upload.
I have just found very interesting explanation how to use Transport of Concentrated Species physics when coupled with Laminar Flow. The article clarifies a lot for me. http://www.comsol.com/support/knowledgebase/1100/ The problem is I can not open the file. If anyone can convert it to 4.3 or 4.3a version file, please do upload.

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2013年4月29日 GMT-4 09:32
Hi

I manage to open it in 4.3a, but I had to load it twice from the KB page ? check that it's really 397 kB big

Else ask support to translate it, they will also check that its compliant ;)

--
Good luck
Ivar
Hi I manage to open it in 4.3a, but I had to load it twice from the KB page ? check that it's really 397 kB big Else ask support to translate it, they will also check that its compliant ;) -- Good luck Ivar

Please login with a confirmed email address before reporting spam

Posted: 10 years ago 2014年12月4日 GMT-5 02:20
Thank U for your sharing, but I failed to use the link. Could you share this document if U have got it?
Thank U very much!

I have just found very interesting explanation how to use Transport of Concentrated Species physics when coupled with Laminar Flow. The article clarifies a lot for me.
www.comsol.com/support/knowledgebase/1100/

The problem is I can not open the file. If anyone can convert it to 4.3 or 4.3a version file, please do upload.


Thank U for your sharing, but I failed to use the link. Could you share this document if U have got it? Thank U very much! [QUOTE] I have just found very interesting explanation how to use Transport of Concentrated Species physics when coupled with Laminar Flow. The article clarifies a lot for me. http://www.comsol.com/support/knowledgebase/1100/ The problem is I can not open the file. If anyone can convert it to 4.3 or 4.3a version file, please do upload. [/QUOTE]

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 2015年6月12日 GMT-4 02:54
Hi

I am establishing a model using laminar flow with concentrated species, and there is always a caculation error. Have you got the useful file to instruct you?i am appreciate it if you can upload it. thanks in advance.
Hi I am establishing a model using laminar flow with concentrated species, and there is always a caculation error. Have you got the useful file to instruct you?i am appreciate it if you can upload it. thanks in advance.

Please login with a confirmed email address before reporting spam

Posted: 8 years ago 2016年6月26日 GMT-4 03:18
hey ..
actually i m working on the same model as you...if in this time u were able to develop the model...can u just send it to me....actually m a beginner and your last upload was of great help to understand the basics.
i will be really thankful to you if u could hep me with this.
p.s. i dont know if this thread is still valid
hey .. actually i m working on the same model as you...if in this time u were able to develop the model...can u just send it to me....actually m a beginner and your last upload was of great help to understand the basics. i will be really thankful to you if u could hep me with this. p.s. i dont know if this thread is still valid

Please login with a confirmed email address before reporting spam

Posted: 8 years ago 2016年10月29日 GMT-4 08:59

Hi

I manage to open it in 4.3a, but I had to load it twice from the KB page ? check that it's really 397 kB big

Else ask support to translate it, they will also check that its compliant ;)

--
Good luck
Ivar


Hi Ivar,

the link shared cannot be found again. do u store this model and if so, would you please upload it? I appreciate it so much!

best regards,
Yuhong
[QUOTE] Hi I manage to open it in 4.3a, but I had to load it twice from the KB page ? check that it's really 397 kB big Else ask support to translate it, they will also check that its compliant ;) -- Good luck Ivar [/QUOTE] Hi Ivar, the link shared cannot be found again. do u store this model and if so, would you please upload it? I appreciate it so much! best regards, Yuhong

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.