直流道PEMFC的综合三维数学模型Ⅱ单电池机理分析  

Comprehensive Three-Dimensional Transport Model of PEM Fuel Cell with Straight Flow Channels Ⅱ Analysis of Mechanics in the Cell

作　　者：刘训良[1] 温治[1] 陶文铨[2] 何雅玲[2] 

机构地区：[1]北京科技大学机械工程学院,北京100083 [2]西安交通大学能源与动力学院,陕西西安710049

出　　处：《沈阳建筑大学学报（自然科学版）》2007年第2期315-319,共5页Journal of Shenyang Jianzhu University：Natural Science

基　　金：国家自然科学基金项目(50236010)

摘　　要：目的研究质子交换膜燃料电池内部的流动和传质过程及电化学反应过程的机理.方法对直流道质子交换膜燃料电池建立综合的三维多组分数学模型,电化学反应速率采用团聚块模型修正,自主开发程序代码对电池内的复杂物理过程进行数值模拟.模拟得到电池内部反应气体的三维速度场、压力场,以及不同电流密度下的气体组分质量分数、局部电流密度和电极反应过电势的三维分布.结果反应气体在电极中的流速比在流道中小3个数量级以上,压力变化不大;阳极反应速率及氢气的传质速率高,电池的极化过电势主要来自于阴极反应;小电流密度下,阴极内氧的组分质量分数、局部电流密度以及电极反应过电势的分布均匀;随着电流密度的增加,这些量趋于不均匀分布,在传质困难的区域局部电流密度值很小,而局部电极反应过电势增大约0.1V,极化的原因主要由于氧组分的传质限制.结论反应气体在电极内的传质是主要由扩散作用引起,在小电流密度时浓差极化较小,随着电流密度的增加,阴极氧组分的传质速率低是产生电池浓差极化过电势的主要原因.The purpose of this paper is to study the mechanism of the flow, mass transfer and electrochemical reaction in the cell. A comprehensive steady-state, three-dimensional （3-D） multicomponent transport model is developed for PEM fuel cell with conventional gas channels. The electrochemical reaction rate of the cell is modified by the agglomerate model. The complicated transport process in the cell is numerically simulated with the code developed by the authors. The numerical results provide the detail 3-D velocity vector fields and pressure fields of gas mixture. Also shown are 3-D distributions of species concentration, electrode reaction overpotential, and local current density at different current densities. Conclusions are drawn as follows： the velocities of gas mixture are three orders of magnitude smaller in the porous electrodes than that in the gas channels, but the pressure drop is small; the hydrogen has greater mass transfer rate and reaction rate in the anode, so the polarization in the cell mostly owes to the cathode reaction; these distribution patterns are relatively uniform at low average current densities; with the increase of the current density, the distribution patterns become more and more non-uniform, the minimum local current density is located at the place where the oxygen has the poorest mass transfer condition, the local electrode reaction overpotential increases about 0.1V, and the cell polarization is mainly caused by the oxygen mass transfer limitation.

关 键 词：质子交换膜 燃料电池 团聚块模型 三维数学模型 

分 类 号：TM911.4[电气工程—电力电子与电力传动]