Conference article

In this work a macroscopic, steady-state, three-dimensional, computational fluid dynamics model of the anode of a high-pressure polymer electrolyte membrane electrolysis cell (PEMEC) is presented. The developed model is used for studying the effect of employing an interdigitated, planar-circular cell design on the distribution of water in the anode. In the electrolysis of water using PEMEC the anode is fed by demineralized water. Throughout the anode, oxygen is produced and a two-phase flow develops. Interdigitated channels assist in avoiding that gaseous oxygen obstructs the transport of liquid water towards the catalytic layer of the electrode. As opposed to the more common serpentine and parallel channels, interdigitated channels force liquid water through the porous gas diffusion layer (GDL) of the electrode. This improves the supply of water, however it increases pressure losses. While interdigitated channels have been examined for planar-square cells in detail, less is known for planar-circular cells. To examine the extent of flow maldistribution, a base case is defined and a parameter variation is conducted relative to it. In the study, the following parameters are examined: water stoichiometry, temperature, GDL permeability and thickness. In conclusion, it is found that the interdigitated flow field results in an uneven distribution across the cell and that the extent depends strongly on the permeability and weaker on the remaining parameters.

Flow maldistribution; PEMEC; Electrolysis; Modeling