Experimental and Numerical Studies of Enhanced Interdigitated Flow Field for PEM Fuel Cells

Abstract

The presence of blockages in the flow field (FF) of proton exchange membrane fuel cells (PEMFCs) increases the mass transport of reactants toward the catalyst layer regions and improves cell performance. In this paper, the effects of channel blockage in a conventional interdigitated FF of PEMFCs are investigated both numerically and experimentally. The tested cell contains a 25-cm2 active area tested at four air flow rates—0.4, 0.7, 1.0, and 1.5 standard liters per minute (slpm). For numerical modeling, a three-dimensional simulation of a repeating unit of a whole cell was used. Blocks were placed in a staggered arrangement along the neighboring flow channels in order to push reacting species into the gas diffusion layer uniformly. The numerical and experimental data showed good agreement. In this paper, the influence of flow channel blockages is analyzed on velocity contours, the distribution of reactants and local current density over catalyst layer, and polarization and power density curves. Blockages increase the pressure drop along the flow channels and also balance of plant pumping power that drives the working fluid within the FF. Hence, the effect of indentation on pressure drop and pumping power is also measured. The results show that channels blocking at 1.5 slpm improve the limiting current density by 9% and enhance the maximum net power (generated power from which the pumping power is subtracted) by 22%.