Numerical modeling of anode-bleeding PEM fuel cells: Effects of operating conditions and flow field design

• Published in: International journal of hydrogen energy Vol. 46; no. 5; pp. 4378 - 4398
• Main Authors: Rizvandi, Omid Babaie, Eskin, Murat Gokhan, Yesilyurt, Serhat
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 19.01.2021
• Subjects: Anode bleeding operation mode; Carbon corrosion; Flow field design; Operating conditions; PEMFC transient modeling; Pseudo-three-dimensional model; Flow field design; Pseudo-three-dimensional model; Carbon corrosion; PEMFC transient modeling; Anode bleeding operation mode; Operating conditions
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2020.10.228

Operating the PEM fuel cell in the dead-ended anode mode reduces the overall cost and complexity of the system but causes a voltage loss and carbon corrosion in the cathode catalyst layer due to hydrogen starvation in the anode. Whereas allowing an ultra-low flowrate at the anode outlet offers a very high utilization of hydrogen and achieves a stable voltage transient. Here, a time-dependent pseudo-three-dimensional, two-phase, and non-isothermal model is developed to study the optimum bleeding rate, which maximizes the hydrogen utilization, achieves a stable cell voltage and avoids carbon corrosion, which is commonly observed when the bleed rate is set to zero, i.e. the dead-ended mode. The model is validated against the experimental data by comparing the polarization curves and cell voltage transients during the dead-ended anode operation of small experimental cells with serpentine and straight anode flow channels. Moreover, the effects of operating conditions on cell performance during the anode bleeding operation mode are investigated. Results demonstrate that the hydrogen utilization exceeds 99% in the anode-bleeding mode without hydrogen starvation, and the cell performance improves significantly for higher anode pressure, lower cell temperature, and lower relative humidity at the cathode inlet. Lastly, it is found that serpentine channels in the anode improve the uniformity of the distribution of hydrogen compared to straight and interdigitated channels in the anode-bleeding mode while the cathode flow field consists of serpentine channels. •Time-dependent pseudo-3D model is applied to various flow fields.•Effects of the operating conditions and flow field designs are investigated.•A metric is developed to quantify hydrogen maldistribution in the anode.•Hydrogen utilization is maximized while maldistribution is avoided.•Very high H2 utilization, exceeding 99%, is achieved with the anode bleeding mode.