Performance enhancement of proton exchange membrane fuel cell by utilizing a blocked regulated tri-serpentine flow field: Comprehensive optimization with variable block heights and multiple auxiliary channels

A blocked tri-serpentine flow field is promising for proton exchange membrane fuel cell (PEMFC) applications, but enhancements in PEMFC performance are imperative to improve efficient utilization of hydrogen energy. To tackle this issue, a blocked regulated tri-serpentine flow field (BRTSFF) is proposed, characterized by blocks with variable heights and multiple auxiliary channels. Utilizing a three-dimensional multiphase PEMFC model, the complete process to achieve the optimal structure of BRTSFF is presented. This involves a sequential optimization of block and rib structures to enhance net output power while limiting pump power, considering impact of varied regions and their synergistic effects on PEMFC performance. Numerical results indicate that the region closest to the flow field outlet exerts the most significant influence on PEMFC performance, and following the optimization of this critical region, increasing the blocking effects in other regions adversely impacts PEMFC performance. Through meticulous adjustment of the blocking effects across various regions, variable block heights, in contrast to a uniform height, elevate oxygen concentration by 17.8% and reduces oxygen non-uniformity from 0.77 to 0.55. Furthermore, rib structure optimization near the flow field outlet reveals a competition between oxygen transport beneath the channel and the rib, where determining the optimal auxiliary channel entrance position and applying this strategy to multiple ribs further reduces pump power by 17.5% and liquid saturation by 4.4%. Overall, BRTSFF enhances net output power by 19.0% over the conventional tri-serpentine flow field at 0.45 V, markedly surpassing the 10.8% achieved by uniform block height, and reduces power loss by 32.4% compared with the uniformly blocked setup. While the optimization results are specific to the examined flow field, the proposed process and its derived conclusions have wide applicability across various scenarios.