Magnetic field-driven regulation of multiphase transport and localized flooding mitigation in parallel-channel PEMFCs

To address the water management challenges in parallel-channel proton exchange membrane fuel cells (PEMFCs), this study proposes an external magnetic-field-assisted transport regulation strategy. A combined experimental investigation and three-dimensional, two-phase, non-isothermal multiphysics model are developed to evaluate the effects of different magnetic flux densities (150, 200, and 250 mT) on coupled heat and mass transport. The developed model is validated against experimental measurements, with a maximum relative deviation below 4%. The results demonstrate that the Kelvin magnetic body force induced by the applied magnetic field redistributes the local pressure field and improves transport uniformity within the cathode flow channels. The enhanced multiphase transport promotes liquid water removal, reduces water accumulation in porous electrodes, and improves oxygen transport, thereby alleviating concentration polarization. Meanwhile, magnetic-field-assisted transport regulation reduces local temperature gradients and enhances thermal uniformity under non-isothermal operating conditions. Consequently, at 250 mT, the maximum current density and peak power density increase by 19.11% and 21.75%, respectively, compared with the case without a magnetic field. This study provides fundamental insights into magnetic-field-assisted multiphase transport regulation and its potential for improving the performance of parallel-channel PEMFCs.