中文摘要：

利用落塔开展了不同重力情况下质子交换膜燃料电池性能的实验研究。对常重力和微重力条件下质子交换膜燃料电池发电时其阴极蛇形流场内部的两相流动开展了可视化现场观测。对重力因素对质子交换膜燃料电池内部传质过程的影响进行了分析和讨论。实验结果表明：在常重力环境中，液态水堆积在竖置流道的底部，无法有效排出．聚集在流道内的液态水与反应气体在流道内形成气／液两相流动。在微重力环境中，液态水在气体推动力的作用下从流道的底部上升并沿流道向出口流动。聚集在流道内的液态水排除后，减小了反应气体（氧气）从流道向催化层的传递阻力，从而使质子交换膜燃料电池的性能得到提高。

英文摘要：

An experimental investigation of proton exchange membrane fuel cells performance under different gravity conditions has been conducted in a drop tower. An in situ visual observation of two-phase flow inside cathode serpentine flow field of a proton exchange membrane fuel cell in normal gravity and microgravity has been performed, respectively, while the fuel cell generated electric-power. The effect of gravity on mass transfer in proton exchange membrane fuel cells was analyzed and discussed. The experimental results indicate that the liquid water accumulate in the bottom of the vertical flow channels in normal gravity condition and can not discharge effectively. The accumulated liquid water and reactant gas form the gas-liquid two-phase flow in flow channels. In micro gravity condition, however, the accumulated liquid water is pushed by gas and flows from the bottom of the channels to the outlet. Removing accumulated liquid water reduces the transport resistance of reactant gas （oxygen） from channels to catalyst layer, and enhances the performance of proton exchange membrane fuel cells.