Uniform Distribution of Species in Fuel Cells Using a Multiple Flow Bifurcation Design

This paper presents the results obtained from the study about flow distribution in maintaining uniformity of flow fields in fuel cells. Three novel flow distribution designs on bipolar plates are proposed for a proton exchange membrane fuel cell (PEMFC). The flow distributors have multiple levels of bifurcations to split a flow into sub-streams of equal flow rates. There are three types of bifurcation structure proposed and studied, which are the 90° tee-type, rounded-type and slanted-type. Experiments were carried out to test the velocities of flows from the multiple channels after bifurcations, and the flow uniformity on the bipolar plate is estimated and studied. Overall evaluation of flow uniformity in the three designs was conducted. The rounded-type bifurcation structure showed the best flow uniformity. After experimental verification of the uniform flow distribution in the novel design, three PEM fuel cell was fabricated which adopted the novel flow fields. From the experimental test and comparison under dry fuel and air condition, it is found that the PEMFC with new flow field can have a better performance. Thorough experimental investigation is planned for the future study.