Abstract:
Proton exchange membrane (PEM) fuel cells operated with hydrogen and air offer
promising alternative to conventional fossil fuel sources for transport and stationary
applications due to its high efficiency, low-temperature operation, high power density,
fast start-up and potable power for mobile application. Power levels derivable from
this class of fuel cell depend on the operating parameters. In this study, a threedimensional
numerical optimisation of the effect of operating and design parameters
of PEM fuel cell performance was developed. The model computational domain
includes an anode flow channel, membrane electrode assembly (MEA) and a cathode
flow channel. The continuity, momentum, energy, and species conservation equations
describing the flow and species transport of the gas mixture in the coupled gas
channels and the electrodes were numerically solved using a computational fluid
dynamics (CFD) code. The effects of several key parameters, including channel
geometries (width and depth), flow orientation and gas diffusion layer (GDL) porosity
on performance and species distribution in a typical fuel cell system have been
studied. Numerical results of the effect of flow rate and gas diffusion layer porosity
on the flow channel optimal configurations for PEM fuel cell are reported.
Simulations were done ranging from 0.6 to 1.6 mm for channel width, 0.5 to 3.0 mm
for channel depth and 0.1 to 0.7 for the GDL porosity. Results were evaluated at 0.3 V
operating cell voltage of the PEM fuel cell. The optimisation results show that the
optimum dimension values for channel depth and channel width are 2.0 and 1.2 mm,
respectively. In addition, the results indicate that effective design of fuel gas channel
in combination with the reactant species flow rate and GDL porosity enhances the
performance of the fuel cell. The numerical results computed agree well with
experimental data in the literature. Consequently, the results obtained provide useful
information for improving the design of fuel cells.
