A numerical investigation of three-dimensional fluid flow in the bipolar plate of a PEMFC with novel configurations of serpentine flow channels

This study investigates modified serpentine flow channels for PEMFCs to reduce pressure loss and secondary-flow effects at bends. Conventional, symmetric, and hybrid configurations with different bend geometries were analyzed using three-dimensional CFD simulations based on pressure loss, velocity distribution, Dean number, secondary vortices, and gas–electrode contact area. The hybrid configuration provided the most favorable pressure-loss-to-contact-area trade-off under the investigated operating conditions. Increasing the bend size reduced pressure loss and secondary flow, while replacing square bends with curvilinear bends further mitigated flow separation and recirculation. Compared with the outward-curvilinear configuration and the conventional channel with a 1.8 mm bend size, the hybrid design reduced pressure loss by approximately 16.5% and 12.5%, respectively. When integrated into the PEMFC model, the hybrid configuration increased the net power density by approximately 5.18% at 0.4 V, confirming its potential for improving PEMFC flow-field performance.