Enhancement effects of the side blockage arrangement in the flow channel on the performance of a proton exchange membrane fuel cell

Abstract

Flow field configuration critically affects the heat and mass transfer process in a proton exchange membrane fuel cell (PEMFC), which is a key factor to ensure efficient and stable operation of fuel cells. Side blockages arranged in the cathode flow channel is proposed for performance improving of PEMFC. Conventional straight, side blockage alternating with straight, side blockage flow channels are studied to analyze the effects of side blockages arrangement on the distribution of velocity, temperature, reactant concentration and water content and the performance of PEMFC. Results show that the O2 mole concentration in the flow field could be increased by the presence of side blockages, thus the convective mass transfer coefficient and performance are both improved. At current density of 2.0 A cm−2, the performance of PEMFC increases by 9.5%. In comparison to the straight flow channel, flow channels installing side blockage present about 1.5 K lower of the maximum temperature, more uniform temperature distribution and increased Nusselt number, indicating the enhancement of heat transfer. Based on field synergy theory, it’s found that the average angles describing the synergetic effect of heat transfer and mass transfer decrease with the installation of side blockages. This reveals the enhancement of the synergetic degree in heat and mass transfer processes under the turbulence of side blockages, which coincides with the improved performance of PEMFC.