Baffle structure effects on mass transfer and pressure drop of HT-PEMFC with orientated flow channels

Abstract

Flow field design is critical to improving the overall performance of high-temperature proton exchange membrane fuel cells. Adding baffles in the flow channel has been proven to be effective in enhancing mass transfer. In this study, fuel cells with different baffle numbers, heights, and arrangements are numerically simulated to investigate the effects of reactant velocity, concentration distribution, and pressure drop on mass transfer and output performance. The results show that baffles are beneficial in improving cell performance, especially under high current density. With the increase in baffle number and height, the concentration of the reactant at the outlet decreases and the output power increases with the increase in pressure drop. The net power density growth rate is defined to characterize the cell performance. A lower pressure drop reduces the pumping power loss generated during reactant transfer, resulting in a staggered baffle structure with the highest net power density of 4329.65 W/m2. Compared with the traditional and parallel baffle channels, this value is improved by about 11.74% and 4.83%, respectively. Therefore, the optimized baffle channel can enhance the mass transfer, reduce the pumping power, and further improve the cell performance, providing an effective guide for the optimal design and development direction of the orientated flow channel.