摘要
对叉指型质子交换膜燃料电池(PEMFC)阴极提出一个二维两相的多组分流体输运模型,应用连续性方程和Darcy定律以及组分扩散方程描述了反应气体和生成水的流动和传质。利用Leverett函数关联毛细压力与水饱和度,采用半经验关系式给出了气液在多孔层的相对渗透率。本模型预测的叉指型PEMFC性能曲线与文献中实验结果符合较好。研究发现,液态水在阴极内由催化层向出口流动是气体流动的剪切力和毛细驱动力共同作用的结果,液态水流速比气体流速小3个数量级或更多,液态水在电极上的分布比较均匀。
A two-dimensional, two-phase and multi-component transport model was developed for the cathode of PEM fuel cell using interdigitated gas distributor. The continuity equation and Darcy＇s law were used to describe the flow of the reactant gas and production water. The advection-diffusion equations were utilized to study species transport of multi-component mixture gas. An empirical relation was used as the permeability function to depict the dependence on saturation and the Leverett＇s function was used for capillary force. The predicted results of the hybrid model agree well with the available experimental data. It was observed that liquid water appears originally in the cathodic catalyst layer over outlet channel under intermediate current and tends to be distributed uniformly by the capillary force with the increase of current. The liquid water flows from catalyst layer towards the outlet channel in the cathode, driven by capillary diffusion and shear force existing in the gas flow, and its velocity is at least three orders of magnitude smaller than that of the gas mixtures.
出处
《太阳能学报》
EI
CAS
CSCD
北大核心
2007年第7期769-774,共6页
Acta Energiae Solaris Sinica
