Influence of trapezoidal channel design on volume power density of ammonia-hydrogen fuel cells

Abstract

Proton exchange membrane fuel cells based on ammonia decomposition gas (ammonia-hydrogen fuel cells) contain about 25% nitrogen at the anode, resulting in lower power density. In this paper, the volume power density enhancement effect of trapezoid channel with different upper edge length is studied. Research shows that the volume power density of trapezoid 0.1, 0.2, 0.4, 0.6 is increased by 53.5%, 62.0%, 81.9% and 108.3% compared with the conventional rectangular channel, respectively, and it is increased by 5.5%, 11.4%, 25.4% and 43.6% respectively, compared with the triangular channel. However, as the upper edge of the trapezoidal flow channel increases, the anode and cathode of the trapezoidal flow channel appear hydrogen hunger with a zero domain of up to 45% and the phenomenon of the horn mouth gradually moving forward respectively. Moreover, longer flow channels have lower fuel utilization efficiency, as low as 76%.