Ex situ visualization of liquid water transport in PEM fuel cell gas diffusion layers

被引:360
作者
Litster, S [1 ]
Sinton, D [1 ]
Djilali, N [1 ]
机构
[1] Univ Victoria, Inst Integrated Energy Syst, Victoria, BC V8W 3P6, Canada
基金
加拿大自然科学与工程研究理事会;
关键词
PEM fuel cell; gas diffusion layer; two-phase flow; visualization; microscale; hydrophobic porous media; fibrous media;
D O I
10.1016/j.jpowsour.2005.03.199
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
A novel fluorescence microscopy technique for visualizing the transport of liquid water in unsaturated hydrophobic fibrous media has been developed and is applied to the gas diffusion layer of a PEM fuel cell. In the experiments, fluorescein dye solution is pumped through the fibrous hydrophobic gas diffusion layer (GDL) and imaged with fluorescence microscopy. Transient image intensity data is correlated to the liquid surface height and is analyzed and presented in the form of three-dimensional reconstructions of the time-evolving gas/liquid inter-face inside the fibrous structure. The high spatial resolution of the visualization can resolve the dynamic transport of liquid water through distinct pathways, which helps to refine understanding regarding liquid water transport mechanism within these porous layers. The physical observations suggest that the water is not transported via a converging capillary tree as suggested in prior work and models. Rather, transport is dominated by fingering and channeling. Based on the physical insight obtained from the experiments, a new water transport scheme is proposed as the basis for developing improved models for water transport in hydrophobic gas diffusion layers. (c) 2005 Elsevier B.V. All rights reserved.
引用
收藏
页码:95 / 105
页数:11
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