Simulation of the effect of channel shrinking rate on the performance of tubular direct ethanol fuel cell

Abstract

Design and optimization of channel has significant effects on mass and heat transfer and comprehensive performance of fuel cells. In this study, a new type of direct ethanol fuel cell with tubular structure is proposed, and the effects of different channel height and width shrinking rate on the current density, water distribution, temperature distribution and pressure distribution on the cathode side of the cell are studied by computational fluid dynamics (CFD). The results indicate that the height shrinking rate is beneficial to increase the pressure drop on the cathode side and improve the removal ability of water, leading to better fuel cells, and the height shrinking rate is 55–77%, the performance of DEFC is improved the best. When the height shrinking rate is 77%, its optimizations have a power density growth rate of 34%, which is about 31.5 mW/cm2.The width shrinking rate has little effect on the fuel cell, reducing the power density to 23.5 mW/cm2. This phenomenon is due to that the reduction of the Catalytic area leads to the oxygen gradient distribution in the Electrode layer, which promotes the discharge of cathode water, but leads to insufficient oxygen in the central region of the fuel cell membrane electrode, resulting in the decrease of current density.