Efficient thermal management is critical for sustaining the performance and durability of Proton Exchange Membrane Fuel Cells (PEMFCs), where excessive operating temperatures accelerate material degradation and reduce power output. Previous studies have explored various cooling channel designs; however, limited research integrates zigzag multi-fin geometries with both computational and experimental validation for fin width optimization under high-velocity cooling. This study presents a combined Computational Fluid Dynamics (CFD) simulation using ANSYS Fluent and experimental investigation of a multi-fin multi-channel cooling system for PEMFCs. The effects of fin widths (0.3–1.0 mm), inlet flow velocities (0.6–3.0 m/s), and cooling media (air, 20% ethylene glycol (EG) solution) were analyzed with respect to cathode surface temperature, power density, and cooling efficiency. Results show that a 0.3 mm fin width with 3.0 m/s inlet velocity reduced the cathode temperature by ~13 K and increased power density by ~40%. The optimized zigzag configuration improved heat transfer uniformity, achieving cooling efficiencies up to 67.0%. Experimental validation confirmed the CFD results with less than 3% deviation. The findings highlight the potential of optimized multi-fin designs to enhance PEMFC thermal stability and electrical output, offering a practical approach for advanced fuel cell thermal management systems.

Effective thermal management is critical for sustaining the performance, durability, and stability of a proton exchange membrane fuel cell (PEMFC). A thorough numerical investigation of six multi-fin zigzag cooling-channel geometries operating under three slope angles (75°, 90°, and 120°) is presented to monitor the combined impact of geometric complexity and channel inclination on cooling performance. In addition, temperature fields, velocity distributions, localized heat flow, total heat removal, and cooling efficiency were reviewed to characterize thermal–fluid behavior of the individual configuration. The results showed that geometric refinement had the strongest influence on cooling performance, with Type 5 (a = 2, b = 4, h = 2) and Type 6 (a = 4, b = 4, h = 2) progressively achieving declining temperature distributions, greater outlet velocities, and modified coolant mixing. Slope angles also affected flow behavior, where reduced inclination extended coolant residence time and elevated inclination intensified secondary flows, although the influence was secondary to geometry. Total heat flow, area-specific heat extraction, and cooling efficiency were highest in Type 5 (a = 2, b = 4, h = 2) and Type 6 (a = 4, b = 4, h = 2), with Type 5 exhibiting an optimal balance between flow disturbance and hydraulic resistance. This study generally presented practical design guidance for next-generation PEMFC cooling systems, proving that optimized multi-fin zigzag channels significantly advanced thermal uniformity and heat-transfer effectiveness under diverse operating conditions.