Applied Energy, Vol.233, 300-311, 2019
Water droplet dynamics in a dead-end anode proton exchange membrane fuel cell
A numerical model was developed in ANSYS Fluent to investigate the dynamic behavior of a liquid water droplet emerging from the gas diffusion layer into the anode flow channel of a dead-end anode proton exchange membrane fuel cell. The volume of fluid method was used with a porous model to account for the multiphase flow and porous media transport through the gas diffusion layer. To mimic the purging effect on water droplet dynamics, the anode flow channel outlet was closed and opened periodically. The closing duration was varied from 15 to 20 ms, while the purging duration was set constant at 3.5 ms, over a total flow time of 50 ms. The results show that the closing duration can be extended to over 20 ms at a low current density. However, it may result in pressure build-ups. For the conditions studied, the current density of 1.0 A/cm(2), operating with a closing duration of 20 ms resulted in the best performance with the least hydrogen wastage (7.12%) and the most water evacuated (69.72%).