Investigation on PEMFC stack cathode gas maldistribution by an experiment-assisted improved flow network and computational fluid dynamics

This study aims to improve cathode gas distribution uniformity in a U-type 140-cell PEMFC stacks by developing an improved experimentally-assisted flow network method (IFNM) that combines computational efficiency with accuracy. The proposed improved flow network method (IFNM) replaces the traditional empirical correction for straight channels with a porous-medium pressure-drop model, providing a feasible framework for describing complex flow field resistance. An experimental-assisted explicit vapor-generation model is proposed and incorporated to account for the influence of electrochemical water production on gas distribution. The porous-medium parameters are experimentally identified from measured flowrate–pressure drop relationships and further validated under multiple operating conditions to ensure the reliability. Comparative results show that IFNM achieves less than 5 % deviation from three-dimensional CFD predictions of flow distribution while offering a two-order-of-magnitude reduction in computational time. Moreover, the IFNM introduces a geometry-based domain partition to distinguish bridge and reaction regions within the flow field, enabling a full-factor analysis of manifold cross-sectional and bridge geometric effects on distribution uniformity. The results demonstrate that manifold geometry is the dominant factor on cathode maldistribution, with the cross-sectional length and width showing strong positive correlations — simultaneous 20 % increases in both dimensions reduce the maldistribution indicator from 7.69 % to 3.64 %.