Numerical investigation of the combined impact of flow channel's geometry and baffle blockage on the performance of proton exchange membrane fuel cells

Abstract

This study investigates the combined effects of flow field cross-sectional shapes and baffle blockage on mass transfer and performance improvement in PEMFCs. Four single-path serpentine channels, square, trapezoidal, triangular, and dovetail, are analysed individually and combined with various designs of rectangular baffles. The effective mass transfer coefficient (EMTC) and the efficient evaluation criterion (EEC) were adopted to evaluate the comprehensive performance of the flow field and baffle designs. Results show that channel width significantly influences mass transfer behaviour, current density, pressure drop, and reactant concentration profiles, while channel depth shows minimal effect. The dovetail channel exhibits superior PEMFC performance, improving current density by 10.47 % over the conventional square channel. Introducing typical, single-hole and multi-hole baffles to the flow field improves mass transfer and enhances fuel cell performance. Typical baffles increase current density by 5.86 %, while single- and multi-hole baffles achieve increments of 6.21 % and 7.61 %, respectively. Although the conventional baffles cause a high pressure drop, adding a central hole reduces the pressure drop while enhancing performance. Finally, the dovetail flow field-baffle arrangement achieves a 14.95 % increase in current density at 0.4 V. In contrast, the triangular flow field-baffle configuration provides the most uniform reactant distribution with minimal pressure drop. This study underscores the crucial role of optimizing flow field geometry and baffle structure to enhance mass transfer and PEMFC performance, highlighting their importance for diverse PEMFC applications.