Abstract:

Fans are used for cooling and feeding oxygen in air-cooling proton exchange membrane fuel cell (PEMFC). For optimal performance, it is essential that the air is distributed as uniformly as possible and supplied sufficiently, which can be adjusted by varying the working distance and voltage of fans, in order to maintain temperature uniform (with the fan working in certain mode). Experiments were carried out for air cooling PEMFC, with the fan system working under the mode of “blowing”, to find the optimal distance. The temperature on the export side of cathode was measured to reflect the heat dissipation by Fluke Ti25 infrared thermal imager. The load box works under constant voltage mode and automatically records output current of stack, to evaluate the output performance. Moreover, an empirical formula is fitted according to the average temperature under different conditions, with working voltage and working distance as independent variables, and average temperature as the dependent variable. The results show that the performance of the stack declines when the fan is at a distance beyond or below the optimal value. At this optimal distance, the distribution of surface temperature is more uniform, the uniformity of unit cell voltage is better, and the required working voltage of fan system is less. This work provides a guideline and serves as a reference to improve the performance of air-cooling PEMFC by increasing the stability and efficiency of the system.

Key words: fuel cell, fluid mechanics, fan system, optimal design, experimental validation

摘要：

风扇被用于空冷型PEMFC电堆的冷却和氧气的供应,空气流速的大小和分布对于提高电堆输出性能和内部温度的均匀性非常关键,可以通过改变风扇的工作电压(风扇工作在恒流模式)和风扇与PEMFC阴极入口的距离来调整。针对实验室自制空冷型PEMFC电堆进行实验来寻找风扇工作距离和工作电压对于电堆性能的影响,并利用多元回归拟合得到以电堆表面平均温度为因变量,以风扇工作电压和风扇工作距离为自变量的经验公式。研究结果表明:当风扇工作距离大于或小于其最优工作距离时,电堆性能均会发生衰减;当风扇处于最优工作距离时,电堆表面温度更加均匀,各单电池电压均匀性得到提高,并且此时所需的最优风扇工作电压更小。该研究对于提高空冷型PEMFC电堆输出性能、增加电堆运行稳定性、提高电堆系统效率等具有重要的指导和参考价值。

关键词: 燃料电池, 流体力学, 风扇系统, 优化设计, 实验验证