A Comparative Study of Different Gas Channel Structures Inperformance Degradation Ofproton Exchange Membrane Fuel Cell

The electrochemical performance and durability of proton exchange membrane fuel cells (PEMFCs) are strongly governed by the geometry and topology of the reactant flow field. In particular, the gas channel configuration plays a critical role in regulating reactant distribution, water management, pressure drop and interfacial mass transport between the gas diffusion layer (GDL) and the catalyst layer. PEMFCs generally exhibit enhanced current density and improved polarization characteristics when a larger fraction of the gas flow channel area is in direct contact with the GDL, thereby promoting more uniform reactant utilization and reduced concentration overpotentials. In the present study, a comparative numerical investigation of different gas channel structures and their influence on PEMFC performance degradation was conducted using COMSOL Multiphysics. Two alternative gas flow channel geometries with identical inlet and outlet cross-sectional areas but differing channel-GDL contact areas were developed and analyzed. A conventional rectangular (cuboidal) parallel flow field and a cylindrical parallel flow field design were selected to systematically assess the impact of channel geometry on electrochemical and transport phenomena. We investigated and observed the hydrogen mass fraction, ionic potential and electronic potential include the oxygen, nitrogen, water mass fractionsand the current density across the membrane. The velocity field vectors and the pressure in the anode and cathode compartments is also studied.For a rectangular (cuboidal) structure, it displays better results for pressure, velocity and membrane current density.