IMPROVEMENT OF THE PERFORMANCE OF THE GAS FLOW CHANNEL IN THE PEM FUEL CELLS

摘要

This study performs numerical simulations to evaluate the convective heat transfer performance and velocity flow characteristics of gas flow channel design to enhance the performance of Proton Exchange Membrane Fuel Cells (PEMFCs). To restrict the current simulations to twodimensional incompressible flows, the flow regime is assumed to be laminar with a low Reynolds number of approximately 200. In addition, the field synergy principle is applied to demonstrate that the increased interruption within the fluid reduces the intersection angle between the velocity vector and the temperature gradient. The interruption within the fluid is induced by different type of obstacles: wave-like, trapezoid-like and ladder-like form and straight form by a gas flow channel. The numerical results show that compared to a conventional straight gas flow channel, the wave-like, trapezoid-like and ladder-like geometry of the proposed gas flow channel increases the mean Nusselt number (Fig.1) by a factor of approximately two. Furthermore, the periodic three patterns (wave-like, trapezoid-like and ladder-like) structure increases the gas flow velocity in the channel and hence improves the catalysis reaction performance in the catalyst layer. Finally, the results show that the three patterns geometry of the gas flow channel reduces the included angle between the velocity vector and the temperature gradient. Hence, the present numerical results are consistent with the field synergy principle, which states that the convective heat transfer is enhanced when the velocity vector and temperature gradient are closely aligned with one another.