Hello,

I am modelling a Solid Oxide Fuel Cell in PRO-STAR to be run on STAR-CD. I am at the stage where I need to implement the the respective electrochemistry that takes place in 2 regions of the cell.

the two reactions i need to model are:

1. H2 + O^2- ---> 2e- + H20 (H2 gas + oxygen ion of -2 charge --> 2 electrons + water)

2. 0.5O2 + 2e- ----> O^2- (half O2 gas + 2 electrons ---> Oxygen ion of -2 charge)

After reading the Star Users Guide, I have ascertained that these are both "Homogeneous" reactions that occur in a small region. Also, both the fuel (H2) and the oxidant (O2) enter the cell separately, therefore I have further narrowed the model to be of the "Unpremixed-Diffusion" type. Continuing in the Users Guide, it seems that I can use either the Kinetic or Complex Chemistry Model... it is here where I am not sure how to continue. Any suggestions are much appreciated.

The complex chemistry model is used for large reaction mechanisms with lots of species and elementary reactions. I think you might be alright with the kinetic model if your approach is right.

I am wondering if you really have homogeneous reactions. Don't you 'supply' the electrons to the oxygen via metal electrodes? Will the reaction 2 take place in the fluid or rather on the surface of your electrode? How do you model the electrons? What about catalytic reactions on the electrolyte?

Regards,

Ralphie

Thanks for your response, Ralphie.

I'm use the Homogeneous Reachtion model because for a composite electrode (YSZ-LSM in my case), the entrie electrode volume, not just the surface, reacts. When it comes to modeling the electrons and ions in the equations, I'm lost...