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 The information provided may be out of date.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.

Integration boundary condition that is probably of circular dependency (dye-sensitized solar cell)

Please login with a confirmed email address before reporting spam

I tried to model the ionic exchange in a dye-sensitized solar cell. The concentration of cations in the electrolyte follows a Boltzmann distribution:

Nc = N0 * exp(-Q/kT). N0 is a constant.

That is, Nc is a variable dependent on N0.

To fulfill ionic conservation, one of the non-local boundary conditions is:

∫Ω Nc*dΩ = N0*Ω , where Ω is the volume of the cell.

That is, the integration of Nc over the entire domain = N0 * volume of the domain.

My question is, how can I fulfill it in Comsol? I know how to add an integration coupling variable (intop1), but what to do next?

Thanks.

3 Replies Last Post 2013年4月29日 GMT-4 14:36
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 13:06
Hi

have you tried to define your integration operand, and then add a gloval equation sub node to your physics with a variable set to the intop1() ... and thenuse this new dependent variable in your approriate equations ?

--
Good luck
Ivar
Hi have you tried to define your integration operand, and then add a gloval equation sub node to your physics with a variable set to the intop1() ... and thenuse this new dependent variable in your approriate equations ? -- Good luck Ivar

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2013年4月29日 GMT-4 13:56

Hi

have you tried to define your integration operand, and then add a gloval equation sub node to your physics with a variable set to the intop1() ... and thenuse this new dependent variable in your approriate equations ?

--
Good luck
Ivar


No I haven't. I don't even know how to do it. Could you explain a little more as to how to do it in Comsol? And what is a sub node?

Thank you.
[QUOTE] Hi have you tried to define your integration operand, and then add a gloval equation sub node to your physics with a variable set to the intop1() ... and thenuse this new dependent variable in your approriate equations ? -- Good luck Ivar [/QUOTE] No I haven't. I don't even know how to do it. Could you explain a little more as to how to do it in Comsol? And what is a sub node? Thank you.

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 14:36
Hi

check the model library (do not forget to update it regularly) there you will find amny examples with usefull hints.

sub node is is a "node" you add to the model tree, byu selecting a main node and righ-tclicking on i,t to see the palette of available sub nodes, these might go quite deep down, and depening one one seting of you physics, you might get new levels of sub-nodes when you righ click further down

--
Good luck
Ivar
Hi check the model library (do not forget to update it regularly) there you will find amny examples with usefull hints. sub node is is a "node" you add to the model tree, byu selecting a main node and righ-tclicking on i,t to see the palette of available sub nodes, these might go quite deep down, and depening one one seting of you physics, you might get new levels of sub-nodes when you righ click further down -- Good luck Ivar

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.