Bio-inspired design of a fence-type triangular flow channel for ammonia-hydrogen fuel cells

Abstract

Appropriate channel design can improve the volume utilization and power density of proton exchange membrane fuel cells with ammonia decomposition gas as fuel (Ammonia-Hydrogen fuel cell, AHFC), and accelerate its application in commercial field. Aiming at the problem of low volumetric power density of AHFC, a triangular flow channel in the shape of a fence is designed based on the general rules of plant growth and simple structure of triangle. The influence of the cross-section size and length of triangular flow channel on gas-water-heat distribution of AHFC is analyzed by using a three-dimensional two-phase numerical model. The results show that the triangular flow channel improves the volume utilization and increases the volumetric power density greatly, and the increase amplitude is related to the load output. With the increase of the load output, the reactive gas gradually appeared starvation phenomenon, the longer the flow channel is, the more obvious starvation phenomenon is, which is opposite to the change trend of the water content in the membrane, and the hot spot value increases significantly. In addition, the maximum volumetric power density of a stack which includes 20-layer triangular channel fuel cells increased by 45% compared to the conventional square channel.