Thermal Transient Performance of PEM Fuel Cells in Aerospace Applications: A Numerical Study.

Polymer electrolyte membrane fuel cells (PEMFCs) are gaining attention as viable energy carriers for future aerospace propulsion systems due to their high-power density, lightweight and compact design, zero emissions, scalability, quiet operation, and relatively reliable performance. However, maintaining optimal performance and durability under transient thermal conditions remains a critical challenge, particularly in aerospace environments. Despite extensive research on PEMFCs, the transient thermal effects remain underexplored. This study employs a validated numerical simulation model to investigate the transient responses of a PEMFC subjected to thermal shock cycles, where the bipolar plate walls experience abrupt temperature drops to 10 °C for durations of 3 to 19 s. The simulation model was benchmarked against experimental data from the literature, demonstrating deviations of less than 10% in the polarization curves, confirming its reliability for predicting transient behaviors. Results reveal that during these thermal shocks, the current density decreases by approximately 15%, from 9263 A/m