Numerical Investigation of Effects of Obstacles in Flow Channels and Depth of Flow Channels for PEMFCs

The channel is a crucial component of the polymer electrolyte membrane fuel cell (PEMFC). Since the channel can change the reactant transfer capability, water removal capability, and distribution of the reactant, it affects the performance and durability of PEMFCs. This study investigated the effects of obstacles in the serpentine-type flow channel on the performance of PEMFCs by computational fluid dynamics (CFD). The height of the obstacles was varied to analyze the electrochemical performances of the fuel cells. In addition, the depth of the flow channel was varied to compare the performances of the PEMFCs. To better represent the real-world tendency, the agglomerate model and the Forchheimer inertial effect were used. The results showed that changes in the channel depth caused greater performance improvements compared to the installation of obstacles, due to the enhanced mass transfer and improved water removal. However, the results for the installation of obstacles showed the lower non-uniformity of the current density and a reduced pressure drop compared to the changes in the channel depth, offering advantages in terms of flooding, the fuel cell life, and the operating cost.