Haokai Xu

The structure of porous media is composed of skeleton particles and pores. Its micro-pores and solid skeleton characteristics lead to the capillary fingering movement of fluid in its porous media driven by capillary pressure. Currently, the methods of constructing porous media are mainly random construction and multi-scale imaging construction. The porous structure constructed by these two methods can show the real microstructure characteristics. The research on multiphase flow in microporous structure mainly includes VOF, MC, LBM, and other methods. In this chapter, taking the classic porous structure of polymer electrolyte membrane (PEM) fuel cell gas diffusion layer (GDL) as an example, GDL porous microstructure is constructed through random algorithm, and multiphase LBM is used to study two-phase flow in porous media to explore the relationship between porous structure characteristics and multiphase flow transport.

The performance of a polymer electrolyte membrane fuel cell (PEMFC) closely depends on internal reactant diffusion and liquid water removal. As one of the key components of PEMFCs, bipolar plates (BPs) provide paths for reactant diffusion and product transport. Therefore, to achieve high fuel cell performance, one key issue is designing BPs with a reasonable flow field. This paper provides a comprehensive review of various modifications of the conventional parallel flow field, interdigitated flow field, and serpentine flow field to improve fuel cells’ overall performance. The main focuses for modifications of conventional flow fields are flow field shape, length, aspect ratio, baffle, trap, auxiliary inlet, and channels, as well as channel numbers. These modifications can partly enhance reactant diffusion and product transport while maintaining an acceptable flow pressure drop. This review also covers the detailed structural description of the newly developed flow fields, including the 3D flow field, metal flow field, and bionic flow field. Moreover, the effects of these flow field designs on the internal physical quantity transport and distribution, as well as the fuel cells’ overall performance, are investigated. This review describes state-of-the-art flow field design, identifies the key research gaps, and provides references and guidance for the design of high-performance flow fields for PEMFCs in the future.