Numerical study of serpentine flow field designs effect on proton exchange membrane fuel cell (PEMFC) performance

The design of flow field greatly influences Proton Exchange Membrane Fuel Cell (PEMFC) performance, as it not only distributes the reactants, also removes the product (water) from the cell. Improper water removal blocks the reaction sites, which results in mass transport losses. A complete 3-D numerical model of PEMFC with a single serpentine (1-S), double serpentine (2-S),triple serpentine (3-S) and 3-2-1 serpentine flow fields with round corner was designed with the help of commercial Computational Fluid Dynamics (CFD) code ANSYS FLUENT. Simulations were carried out to investigate the effect of four flow fields on distribution of pressure, mass fraction of H-2, O-2, current flux density distribution, water content of membrane, and liquid water activity in the flow channels as well as the functioning of cells. Performance properties of proposed four designs were evaluated and found that 3-2-1 serpentine flow field performance is better than the 1-S, 2-S, and 3-S flow fields for the given flow rates of reactants and this 3-2-1 serpentine flow field model was validated with literature experimental data. The results also show that the velocity in channels increases with a decrease in the number of flow passes, which improve the reactions in the catalyst layers, reaction product removal from the cell thus reduces the concentration losses and improves the cell performance.