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-   -   electrochemical reacation in the fuel cell? (http://www.cfd-online.com/Forums/fluent/33971-electrochemical-reacation-fuel-cell.html)

Kim June 15, 2004 10:59

electrochemical reacation in the fuel cell?
 
Hallo, everyone!

I am now modelling about the fuel cell(SOFC). With defining of the electrochemical reaction I am a little confused.

I want to define the reaction H2 + 1/2 O2 --> H2O and have a UDF program, where the VR_RATE is defined as the function of current density.

What I do not know, is, how I have to define the reaction in REACTION pannel, e.g. rate exponent or Arrhenius rate, etc. Also I have no data of them. Can you anybody me explain?

Regards

*P.S. Is there anyone who is modeling the fuel cell? I want to share the information.

Ari June 16, 2004 05:15

Re: electrochemical reacation in the fuel cell?
 
Hi Kim,

I'm modelling a PEM fuel cell and I've to define source terms with UDF for modelling electrochemical reaction without use reaction panel, because FLUENT 6.0 does not provide this kind of reactions.But I'm not sure if it's the same for SOFC type.

Kim June 18, 2004 07:50

Re: electrochemical reacation in the fuel cell?
 
Thank you for the answer. I think that you are right to define the electrochemical reaction without using reaction panel.

I have another question. There are noramlly four parts in fuel cell: interconnector, gas channel, electrode and electrolyte.

In which part have you defined this reaction source term? I think the reaction occured in electrode(anode in SOFC)...

When it is so, must I define the source term only in electrode part, or in gas channel and electrolyte parts as well for the mass (or species) balance equations?

Because until now I have worked with FORTRAN program, I have not catched on the model of the fuel cell in Fluent yet and am so confused.

I thank you for your help and advice.

Ari June 18, 2004 10:39

Re: electrochemical reacation in the fuel cell?
 
You have to define the source terms for products and reagents on corresponding electrode(see also user's guide chap.6). My doubt is about water in gas channels: do you consider only steam or steam and liquid water(multiphase model)? In the last case is it available energy equation in FLUENT 6.0?

P.S: Are you using FORTRAN (instead of C++)for a particular reason ???

Kim June 22, 2004 10:34

Re: electrochemical reacation in the fuel cell?
 
First of all, sorry for my late answer and thanks for your information!! I read now the user's guide chap.6.

About your question, whether in gas channel only steam exist or liquid water also exist, I don't know well. As you know, SOFC is operated at high temperature (700-1000 oC) and only steam exist. But, I think, in PEMFC it is not so. I am sorry that I cannot help you.

There was not a particular reason to use FORTRAN. --;; I have learned FORTRAN in computer course of my university (a long long time ago :)) and my predecessor had worked with FORTRAN, too.

Ari June 23, 2004 16:44

Re: electrochemical reacation in the fuel cell?
 
Thanks for your response!!!

Even if I have learned C++ in my computer course and I'm going to work with it, I'd like to watch (if it's possible) your UDF program!?!

Bye,

Ari


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