Three-dimensional effects of liquid water flooding in the cathode of a PEM fuel cell
Three-dimensional effects of liquid water flooding in the cathode of a PEM fuel cell
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DOI：
10.1016/s0378-7753(02)00624-9
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发表时间：
2003-03
影响因子：
9.2
通讯作者：
Dilip Natarajan;T. Nguyen
中科院分区：
文献类型：
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作者：
Dilip Natarajan;T. Nguyen
在文献中可获得的用于常规气体分布器的二维模型被扩展以考虑沿通道长度的尺寸沿着。将通道离散成串联的对照体积，其被处理为充分混合。在每个控制体积中加入迭代求解程序以确定平均电流密度和相应的耗氧率和产水率。基于化学计量流速和从前述对照体积获得的溶液计算下游通道浓度。模型结果与实验数据和现有的二维模型的比较表明，占氧浓度的变化沿着通道和其对电流密度的影响是准确预测阴极性能的关键。电流密度沿着通道的变化受到由反应引起的消耗和水蒸发引起的稀释引起的氧浓度变化的强烈影响。有利于更好地通过蒸发去除水的操作参数，如较高的温度和化学计量流速以及较低的入口流湿度，导致较高的净电流。导致氧浓度损失最小的操作条件导致沿沟道沿着更均匀的电流密度分布。
A two-dimensional model available in the literature for conventional gas distributors was expanded to account for the dimension along the length of the channel. The channel was discretized into control volumes in series that were treated as well mixed. An iterative solution procedure was incorporated in each control volume to determine the average current density and the corresponding oxygen consumption and water generation rates. Downstream channel concentrations were calculated based on stoichiometric flow rates and the solution obtained from the preceding control volumes. Comparison of the model results with experimental data and the existing two-dimensional model showed that accounting for the oxygen concentration variations along the channel and its effect on the current density is critical for accurately predicting the cathode performance. Variations in the current density along the channel were strongly influenced by the changes in oxygen concentration caused by consumption due to reaction and dilution caused by water evaporation. Operating parameters that facilitated better water removal by evaporation like higher temperature and stoichiometric flow rates and lower inlet stream humidity resulted in higher net current. Operating conditions that resulted in minimal loss in oxygen concentrations resulted in a more uniform current density distribution along the channel.