How do I calculate the Limited Current Density?

[dancingenigma]

Hello,
I'm calculating the Polarization curve for my PEM Fuel Cell. I am stuck on one value the Limited Current Density.

I have all the values but I'm not sure how I deal with the two different bulk concentrations of the reactants(air and hydrogen). Do I add these together or keep them seperate and have two Limited current density equations and calculate it someway??

Can anyone please help!

 

[thermcool]

If i understand your question correctly,
I think you have separate the two bulk concentration, normally in the calculation of the limiting current density you assume 100% conc of the hydrogen.