equation(5a)Φα(r)=vi(r)nelFequation(5b)dn?α,el(r)2πrdr=Φα(r)where the areic molar flow Φα(r) of the species α is due to the electrochemical reaction, n?α,el(r) is the molar flow rate of the chemical specie α on the surface of the electrode in the r direction, nel is the number of electrons transferred per c-Myc tag in the reaction and ν is the stoichiometric coefficient (ν = −1 consumed species, ν = +1 produced species).
The molar flow rates related to back-diffusion are derived from the solution of the polarization equation of the model (see Section 3.2.2) at open circuit. The model estimates the equilibrium potential by using the Nernst equation and compares it with the experimental open circuit voltage (OCV); the difference is compensated by the generation of a H2O (or CO2) flow rate, i.e. n?brn, due to the burning of H2 (or CO), which is used to correct the molar balances on the surface of the fuel electrode. The corrected molar flow rates of the chemical species are:equation(6)n?H2(CO)(r)=n?H2(CO)el(r)-n?brn(r)equation(7)n?H2O(CO2)(r)=n?H2O(CO2)el(r)+n?brn(r)