Qualitative and quantitative determination of liquid water distribution in a PEM fuel cell

Abstract

In this work, a numerical investigation of a PEM fuel cell with a five-serpentine flow field is conducted. The numerical model is first validated against the experimental polarization curve, obtaining values for reference exchange current density and cathode charge transfer coefficients for further simulations. The model validation is extended by qualitative and quantitative comparison of the water accumulation within the fuel cell, experimentally obtained with neutron imaging. More intense water accumulation is observed towards the channel outlet due to a progressive saturation of the gas flow with water vapor. Due to the gravity effect, the water mainly accumulates on the lower area of the fuel cell and a higher amount is present in blocks oriented upwards. The used numerical model considers the capillary pressure at the GDL/channel interface, showing to have a great impact on the liquid water thickness profile. Satisfying agreement between simulations and the experiment is achieved.