A comprehensive investigation on a modified interdigitated-jet hole flow field for under-rib mass transfer

The flow field is a crucial component of proton exchange membrane electrolyzer cell (PEMEC), significantly impacting cell performance and distribution uniformity. This study introduces a modified flow field structure, named the Modified Interdigitated-jet hole Flow Field (MIJFF), based on the interdigitated-jet hole flow field with added under-rib holes. The goal is to increase water supply to the porous electrode and facilitate gas discharge from the diffusion layer , thereby improving under-rib mass transfer and enhancing the uniformity of current density. Three control groups are compared: a single-path serpentine flow field, an interdigitated flow field, and an interdigitated-jet hole flow field. A two-phase, muti-dimensional model is developed to simulate different flow field structures, which are then validated through the experimental approaches. Results indicate that the MIJFF, with added under-rib holes, can better improve under-rib mass transfer, provide water supply and allow timely gas expulsion, avoiding unevenness and performance degradation due to local gas accumulation. Furthermore, the introduction of under-rib holes further increases vertical flow velocity. Compared to the control groups, applying MIJFF to the anode improves liquid saturation , current density and temperature distribution uniformity by 19.65 %, 36.24 % and 37.64 %, respectively, while increasing vertical flow velocity in the channel by 60.6 %. • Comprehensive 3D two-phase multi-channel PEM electrolyzer model. • A modified flow field is proposed with the introduction of under-rib holes. • The MIJFF improves mass transfer and increases vertical flow rate by 60.6 %. • The MIJFF enhances current density uniformity by 36.24 %.