A three-dimensional, non-isothermal and multiphase model of high
temperature proton exchange membrane fuel cells is built to investigate
water and phosphoric acid transportation, in which a spherical
agglomerate model considering catalyst layer structure and liquid phase
fraction is applied to determine the electrochemical kinetics in the
cathode catalyst layer. Experimental polarization curve, water
proportion in the anode outlet gas and phosphoric acid distribution are
selected for validation. It is found that the simulated results can
represent the experimental data with reasonable accuracy. Based on the
model, the effects of current density and stoichiometry on the variable
distributions are analyzed. The results show that water in anode is
mainly from cathode by concentration diffusion of liquid water. A higher
current density leads to a greater electro-migration of phosphoric acid
from cathode to anode and a higher liquid phase fraction in anode,while
a lower phosphoric acid concentration in the fuel cells.