A three-dimensional heterogeneity analysis of electrochemical energy conversion in SOFC anodes using electron nanotomography and mathematical modeling
A three-dimensional heterogeneity analysis of electrochemical energy conversion in SOFC anodes using electron nanotomography and mathematical modeling
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DOI：
10.1016/j.ijhydene.2018.04.023
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发表时间：
2018-05
影响因子：
7.2
通讯作者：
T. Prokop;K. Berent;H. Iwai;J. Szmyd;G. Brus
中科院分区：
文献类型：
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作者：
T. Prokop;K. Berent;H. Iwai;J. Szmyd;G. Brus
本文提出并验证了一个全三维多相微尺度固体氧化物燃料电池阳极输运现象的数值模型。Butler-Volmer模型与电导率和扩散率的经验关系（特别是Fuller-Shetler-Giddings方程）和气体试剂输运的菲克模型相结合。对商用SOFC堆叠阳极进行FIB-SEM断层扫描，并对所得图像进行处理以获取输入数据。提出了一种估算三相三维数值网格三相边界长度密度局部值的新方法。利用内部程序对模型方程进行了求解，并在其适用范围内与解析解进行了比较。进行了一项有限参数研究，以定性地评估模拟性能和异质性的影响。尽管SOFC阳极的性能高度依赖于其各向异性和三相微观结构的几何形状，但很少有微观尺度的数值模型模拟这些电极内的输运现象。
In this paper a fully three dimensional, multiphase, micro-scale solid oxide fuel cell anode transport phenomena numerical model is proposed and verified. The Butler-Volmer model was combined with empirical relations for conductivity and diffusivity - notably the Fuller-Shetler-Giddings equation, and the Fickian model for transport of gas reagents. FIB-SEM tomography of a commercial SOFC stack anode was performed and the resulting images were processed to acquire input data. A novel method for estimating local values of Triple Phase Boundary length density for use in a three-phase, three-dimensional numerical mesh was proposed. The model equations are solved using an in-house code and the results were verified by comparison to an analytical solution within the range of its applicability. A limited parametric study was performed to qualitatively assess simulation performance and impact of heterogeneity. Despite the high dependence of the SOFC anode performance on the geometry of its anisotropic, three-phase microstructure there are very few micro-scale numerical models simulating transport phenomena within these electrodes.