Heat/mass transfer in porous electrodes of fuel cells

This paper has provided an innovative aspect in the heat/mass transfer of fuel-cell related studies. A heat/mass coupled modeling approach is presented to predict the transport phenomena inside the porous electrode of a fuel cell. The energy equations based on the local thermal non-equilibrium (LTNE) are derived to resolve the temperature difference between the solid and fluid phases inside the porous electrode. The surface heat transfer is coupled with the species transports via a macroscopic electrochemical model on the reaction boundary. First, a general criterion for the local thermal non-equilibrium in porous electrodes is proposed in terms of non-dimensional parameters of engineering importance. Then, the significance of local thermal non-equilibrium in a typical porous electrode is assessed. Furthermore, detailed distributions of the local temperature, local Nusselt number, species concentration, and electric current density inside the porous electrode of fuel cells are presented. Finally, the effect of LTNE parameters on the thermal-fluid behaviors in the porous electrode is investigated.