Experimental and numerical analysis of a three-dimensional flow field for PEMFCs

It has been well recognized that both the performance and operation stability of proton exchange membrane fuel cells (PEMFCs) are closely associated with water transport and accumulation behaviors in the membrane electrode assembly. Therefore, an optimal water management is highly desired. Conventional serpentine flow field (CSFF) can effectively facilitate water removal and prevent water flooding. However, CSFF would cause a high pressure drop from the inlet to outlet, thus resulting in large parasitic power loss. In this study, a novel three-dimensional flow field (WSFF), patterned with waved serpentine flow channels, is designed and analyzed by combing the simulating method with experimental method. A three-dimensional, multi-phase, steady, isothermal, laminar simulation model is firstly established based on FLUENT PEM fuel cell module, and this model reveals that WSFF is overall better than CSFF in promoting oxygen transport though the diffusion layer and removing liquid water accumulated in microstructure. Its periodic waved structure introduces cyclical variation of local flow direction, local flow velocity and local pressure, thus leading to enhanced forced-convection. The superior performance of WSFF has also been experimentally verified, proving that WSFF not only enables a lower pressure drop over the entire current density range, but also improves the cell performance in comparison to CSFF at high current density region. Specifically, there is a 17.8% increment in the peak power density due to the use of WSFF.