Effects of vortexes in feed header on air flow distribution of PEMFC stack: CFD simulation and optimization for better uniformity.

Distribution uniformity is critical to achieve high performance for proton exchange membrane fuel cell (PEMFC) stacks. In this work, air flow distribution of a 30 kW "U-type" stack of 100 unit cells is investigated by computational fluid dynamics (CFD) simulation, Burgers vortex model is introduced to describe the mechanism of flow maldistribution. Three cases are presented to evaluate the effects of vortexes on the distribution uniformity under various average current densities, and obtain optimized design for better uniformity. The results show that the vortexes usually generate in the feed header, the flow vortex structures are governed by the feed header's configuration. The distribution uniformity reduces dramatically with the increase of current density and the generation of vortexes. The cells that locate in the positions of vortexes get less flow allocation than other cells, distribution uniformity can improve by optimizing the feed header's configuration to change the vortex structure of flow field. [Display omitted] [ABSTRACT FROM AUTHOR]