Optimization and mass transfer analysis under the ribs of multi-serpentine flow fields

Abstract

This study aims to enhance the performance of Proton Exchange Membrane Fuel Cell (PEMFC) by optimizing the design of a three-channel serpentine flow field. The focus is on the introduction of sub-channels beneath the flow field ribs, utilizing the pressure differential between the main and sub-channels to strengthen lateral convection under the ribs, thus achieving uniform distribution of reaction gases. Using Computational Fluid Dynamics (CFD) methods, the performance of traditional and optimized flow fields were compared across various metrics. The results show that the introduction of sub-channels significantly improves gas mass transfer efficiency, enhances the uniformity of oxygen concentration and current density, and optimizes water content on the proton exchange membrane. At a voltage of 0.5 V, the Improved Serpentine Flow Field (ISCF) exhibits a notable enhancement in current density, increasing from 1.501 A/cm2 in the Traditional Serpentine Flow Field (TCSF) to 1.654 A/cm2 in the ISCF. This represents a significant 10 % increase in current density. Concurrently, the uniformity index climbs from 0.84 to 0.898, marking a 7 % improvement in uniformity. Furthermore, the ISCF design achieves a substantial reduction in pressure drop, decreasing from 1631 Pa to 1212 Pa, a reduction of 26 %. Additionally, the expansion of sub-channel width markedly boosts cell performance, whereas the Increase in sub-channel height reaches a saturation point beyond a certain threshold, indicating an optimal range for dimensional adjustments.

Keywords

• PEMFC
• CFD
• Flow field design
• Mass transfer
• Uniformity