In situ visualization study of CO2 gas bubble behavior in DMFC anode flow fields
In situ visualization study of CO2 gas bubble behavior in DMFC anode flow fields
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DOI：
10.1016/j.jpowsour.2004.05.033
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发表时间：
2005-01-04
影响因子：
9.2
通讯作者：
Ye, Q
中科院分区：
文献类型：
--
作者：
Yang, H;Zhao, TS;Ye, Q
本文报道了一种自制的透明直接甲醇燃料电池（DMFC）阳极流场中CO2气泡行为的可视化研究。DMFC由一个活性面积为4.0 × 4.0 cm（2）的膜电极组件（MEA）、两个具有单个蛇形通道的双极板和一个透明外壳组成。研究表明，在低电流密度下，阳极流场中出现了离散的小气泡。在中等电流密度下，除了小的离散气泡外，还形成了许多气栓。在高电流密度下，流场主要为较长的气栓。实验还表明，电池的方向有一个显着的影响，电池的性能，特别是在低甲醇流速;对于目前的流场设计的最佳电池性能时，可以实现电池垂直取向。结果表明，较高的甲醇溶液流速减少了流场中气栓的平均长度和数量，但导致甲醇穿越增加。特别是，甲醇溶液流速对电池性能的影响在低温下变得更加明显。温度对气泡行为和电池性能的影响也进行了研究。此外，对于目前的流场组成的一个单一的蛇形通道，通道阻塞现象所造成的CO2气栓在这项工作中的所有测试条件下从未遇到。(C)2004 Elsevier B. V.保留所有权利。
This paper reports on a visual study of the CO2 bubble behavior in the anode flow field of an in-house fabricated transparent Direct Methanol Fuel Cell (DMFC), which consisted of a membrane electrode assembly (MEA) with an active area of 4.0 x 4.0 cm(2), two bipolar plates with a single serpentine channel, and a transparent enclosure. The study reveals that at low current densities, small discrete bubbles appeared in the anode flow field. At moderate current densities, a number of gas slugs formed, in addition to small discrete bubbles. And at high current densities, the flow field was predominated by rather long gas slugs. The experiments also indicate that the cell orientation had a significant effect on the cell performance, especially at low methanol flow rates; for the present flow field design the best cell performance could be achieved when the cell was orientated vertically. It has been shown that higher methanol solution flow rates reduced the average length and the number of gas slugs in the flow field, but led to an increased methanol crossover. In particular, the effect of methanol solution flow rates on the cell performance became more pronounced at low temperatures. The effect of temperature on the bubble behavior and the cell performance was also examined. Furthermore, for the present flow field consisting of a single serpentine channel, the channel-blocking phenomenon caused by CO2 gas slugs was never encountered under all the test conditions in this work. (C) 2004 Elsevier B.V. All rights reserved.