[P.Charoen-amornkitt]

I'm currently working on fuel cell add-on module to investigate the steady-state performance of 3-channel serpentine flow field PEMFCs.

I think I'm having a problem to obtain a converged solution since the "reversed flow on pressure outlet" massage is shown after a few iteration (about 10 and keep occurring) and the current density in the console window also too high for the high voltage. I have already follow the suggestion (section 2.9) in the Manual which suggest to turn off Joule Heating and Reaction Heating in the Fuel Cell and Electrolysis Models dialog box for the first few iterations after initialization.

Any suggestions would be greatly appreciated. Thank you very much.

Best Regards,
Patcharawat Charoen-amornkitt

[A CFD free user]

Hi,
Based on my experience in using PEMFC module, receiving reversed flow in low voltage is something usual. I mean, when you work on low voltage, which actually is equivalent with high current density (if you set current density in boundary conditions), it's quite possible to see reversed flow in console. But, your problem is quite different. I suppose, you have a problem in your mesh or even you may set B.C inappropriately. So, check it out and see what you did wrongly. Regarding serpentine channels, you need to be very careful. You might have had some problem in generating interior faces between GDL and channels. So, check it too.

[P.Charoen-amornkitt]

Thank you for your suggestion
I've found that I have set Specified Flux (Instead of Specified Value) for the Water Saturation in the UDS Boundary Condition of Inlet. But after I've changed and run a calculation again, a trend of residual is become strange (not like a wave in fig.4 of tutorial http://lljk.org/cfd/pemfc.pdf) and Current density is going up to more than 1.4 A/cm^2.
By the way, I've used parallel processing.

Thank you

Best Regards
Patcharawat Charoen amornkitt

[A CFD free user]

@Patcharawat
Ok, it's good to hear that you found at least part of the problem. I still insist that you're making something wrong. I've run this tutorial for many times and I didn't see anything weird. The only thing I faced for the first time that I received divergent error was velocity direction in inlets. Actually, in tutorial manual, there was nothing about how to set velocity vector direction. So, I didn't change it to normal B.C, and hence, I repeatedly received divergent error. After that, I never saw anything wrong regard this tutorial. If you think that a case file of this tutorial could be helpful, send me your email and I will send you a case file which definitely works out.
Good luck

[sabrina sabi]

Originally Posted by P.Charoen-amornkitt

Thank you for your suggestion
I've found that I have set Specified Flux (Instead of Specified Value) for the Water Saturation in the UDS Boundary Condition of Inlet. But after I've changed and run a calculation again, a trend of residual is become strange (not like a wave in fig.4 of tutorial http://lljk.org/cfd/pemfc.pdf) and Current density is going up to more than 1.4 A/cm^2.
By the way, I've used parallel processing.

Thank you

Best Regards
Patcharawat Charoen amornkitt

please send th tutorial pdf this my émail sabrina.sabi2005@gmail.com
thanx

[Sayantan Biswas]

I'm working on Copper Electrorefining process (single Phase) in Fluent.
In 'Species Transport model' Electro-chemistry option is there.


1) How do I add an electrolyte (liquid state) consist of Water+CuSO4+H2SO4 solution (having certain Cu concentration) ?

2) How do I add Cu+2 ions(or any metal ions) and Cu in the reaction mixture (only fluid type materials can be added in reaction Mixture) so that I can define the electro chemistry (cathodic/anodic) reaction in Species Transport model?

Thanks in Advance

[dnmy]

i got the same problem， if you solved it， please tell me the solution， thanks a lot.