Abstract:

Two dimensional models based on the typical part in the flow field of PEM fuel cell were presented to analyse the characteristics of liquid droplet motion at the gas diffusion layer（GDL）/gas flow channel（GFC）interface.There were some regular relationships among the contact angle hysteresis（the difference angle between the advancing and the receding angle of moving droplet），the height of the droplet and the velocity of the shear flow，however，the length of the typical part chosen by random had no effect on the result.This model also coupled the condition when the droplets just ran-off from the surface，and reflected the trend of droplet moving，chasing and coalescing.Analysis showed that：lower flow passage，higher fluid velocity and adopting hydrophobic GDL interface to increase the instability of droplets，while using hydrophilic GFC interface to get bigger acceleration were all good ways for removing water from the fuel cell by corner flow.

摘要：

针对燃料电池流场内任意选取的特征单元建立二维模型，分析在剪切流作用下附着在扩散层（GDL）/流道（GFC）表面液滴的运动特征，认为液滴运动时迟滞角（液滴运动过程中前进角与后退角间的差值）与液滴高度、气体流速存在着一定关系;而与所选取的特征单元长度无关。模型还有效耦合了实验总结的液滴开始运动的条件关系式，真实反映了液滴开始运动、不断加速追赶及聚并的运动趋势。结果表明：选取矮流道，增大气体流速，采用疏水的GDL增大液滴的不稳定性，同时增加流道表面的亲水性，有利于液滴获得较大加速度，并以拐角流的形式快速从电池内排除。