Effective Macroscopic Equations for Species Transport and Reactions in Porous Catalyst Layers
Effective Macroscopic Equations for Species Transport and Reactions in Porous Catalyst Layers
复制标题
多孔催化剂层中物质传递和反应的有效宏观方程
DOI：
10.1149/2.037408jes
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发表时间：
2014
影响因子：
3.9
通讯作者：
P. Berg
中科院分区：
文献类型：
--
作者：
M. Schmuck;P. Berg
多孔催化剂层的宏观模型是从微观描述中推导出来的，其中包括充满液态水的周期性分布的孔隙中氧气的还原。虽然为PEM燃料电池中的阴极催化剂层建立了特定的传输方程，但是相同的多尺度方法将产生数学上类似的其他类型的电极的控制方程。宏观传输特性，如多孔介质（校正）张量，达西定律和有效的巴特勒-沃尔默方程，固有地联系在一起的动态在微观尺度上，可以计算在一个相当简单的方式下，假设当地的热力学平衡。在周期性和强对流的情况下，我们也得到所谓的扩散色散关系，如泰勒-阿里斯色散。
A macroscopic model for a porous catalyst layer is derived from a microscopic description that includes the reduction of oxygen in periodically distributed pores filled with liquid water. While specific transport equations are established for a cathode catalyst layer in a PEM fuel cell, the same multi-scale approach would yield governing equations for other types of electrodes which are mathematically analogous. Macroscopic transport characteristics such as porous media (corrector) tensors, Darcy's law and an effective Butler-Volmer equation, are inherently linked to the dynamics at the microscale and can be computed in a fairly straightforward manner under the assumption of local thermodynamic equilibrium. In the case of periodic and strongly convective flows, we also obtain so-called diffusion-dispersion relations, eg Taylor-Aris dispersion.