An Experimental Investigation of Air Water Flow Through Different Flow Field Designs of a PEMFC Bipolar Plate in the Presence of Micronized Wax

Water, a byproduct of the chemical reaction in a Proton Exchange Membrane Fuel Cell (PEMFC), is removed by the air flowing over the cathode. However, when water production rate is more than its rate of removal, water may flood the fuel cell cathode, cutting off the air supply and stopping the reaction. A bio-mimetic solution to the water management problem was proposed in an earlier work where micronized wax was introduced along with the air that would help encapsulate the water droplets facilitating their quick removal from the fuel cell. Based on earlier results, further investigation is done to study different bi-polar flow field designs for effective water management, using bio-mimetic micronized wax. The different flow field designs studied in this work consists of parallel and single serpentine channels on graphite plates under simulated fuel cell load conditions. The effect of micronized wax on the two-phase flow regimes at different flow field orientations is also analyzed. It is clearly observed that the presence of micronized wax significantly helps in water movement in all air flow channels designs and orientations. It is hypothesized that introduction of micronized wax along with the air flow will allow the use of parallel flow field bi-polar plate designs in operating fuel cells with significantly reduced air side pressure drop instead of the prevalent single serpentine channel flow field designs.