Fractal model for predicting the effective binary oxygen diffusivity of the gas diffusion layer in proton exchange membrane fuel cells
Fractal model for predicting the effective binary oxygen diffusivity of the gas diffusion layer in proton exchange membrane fuel cells
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DOI：
10.1016/j.jpowsour.2010.01.080
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发表时间：
2010-08
影响因子：
9.2
通讯作者：
Ying Shi;Hongyi Wu;S. Quan;Jinsheng Xiao;M. Pan
中科院分区：
文献类型：
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作者：
Ying Shi;Hongyi Wu;S. Quan;Jinsheng Xiao;M. Pan
提出了一个分析模型来预测质子交换膜燃料电池(PEMFCs)中多孔气体扩散层(GDL)的有效二元氧扩散系数。在这项研究中，我们考虑了多孔GDL的分形特征以及它的一般微观结构，并采用Bosanquite方程推导出了有效扩散系数。GDL的分形表征使我们能够以连续的方式模拟有效扩散系数，同时考虑孔尺寸分布的影响。与其他两个在质子交换膜燃料电池模拟中被普遍接受的理论模型的比较表明，这三个模型都有相似的趋势，这表明我们提出的模型是有充分依据的。此外，预测的两个样品的有效二元氧扩散系数表明，经聚四氟乙烯(PTFE)处理后，GDL的有效二元扩散系数降低。基于参数效应分析，有效二元扩散系数与弯曲分维呈负相关，而与孔隙面积、孔隙度或平均孔径的分维呈正相关。该模型有利于有效扩散系数的快速预测以及质子交换膜燃料电池的多尺度建模，从而有利于GDLS和质子交换膜燃料电池的设计。
We propose an analytical model to predict the effective binary oxygen diffusivity of the porous gas diffusion layer (GDL) in proton exchange membrane fuel cells (PEMFCs). In this study, we consider the fractal characteristics of the porous GDL as well as its general microstructure, and we adopt the Bosanquet equation to derive effective diffusivity. The fractal characterization of GDL enables us to model effective diffusivity in a continuous manner while taking into account the effect of pore size distribution. Comparison to two other theoretical models that are generally accepted in the simulation of PEMFCs shows similar trends in all three models, indicating that our proposed model is well founded. Furthermore, the predicted effective binary oxygen diffusivities of two samples show that after treatment with polytetrafluoroethylene (PTFE), the effective binary diffusivity of the GDL decreases. Based on the parametric effect analysis, we conclude that effective binary diffusivity is negatively correlated with tortuosity fractal dimension but positively correlated with the fractal dimension of pore area, porosity, or mean pore diameter. The proposed model facilitates fast prediction of effective diffusivity as well as multi-scale modeling of PEMFCs and thus facilitates the design of the GDLs and of PEMFCs.