一种新型流道对燃料电池气体扩散层除水性能的模拟研究

Simulation on evaporative water removal from fuel cell gas diffusion layer by a novel wave flow channel

燃料电池冷启动前,需要通过气体吹扫去除内部多余水分,停车后的吹扫对于燃料电池在低温下能否成功启动有着至关重要的影响。为了更有效地去除电池内部水分,提出一种有利于去除气体扩散层内部水分的新型波形流道,通过多物理场仿真软件(COMSOL Multiphysics)研究不同角度的波形流道对气体扩散层水分去除的影响以及水分去除的机理。计算结果表明:与传统的直形流道相比,这种新型波形流道能够增大气体扩散层上方的气体流速,有利于去除气体扩散层内部的水分,揭示了吹扫对气体扩散层水分去除的3个特征阶段:高饱和度区、恒速区以及快速下降区。

The excess moisture in PEMFCs needs to be removed by gas purging before the cold start-up of PEMFCs.The purging after shutdown has a vital impact on the successful start-up of PEMFCs at low temperatures.In order to effectively remove moisture in the gas diffusion layer,a new waveform channel was proposed.The effects of waveform channel from different angles on moisture removal and the mechanism of water removal were studied by COMSOL Multiphysics.The results show that compared with traditional straight channels,the new waveform channel can increase gas velocity above the gas diffusion layer,which is beneficial to the removal of moisture in the gas diffusion layer.The results show three characteristic stages of moisture removal in the gas diffusion layer:high saturation zone,constant velocity zone and rapid descent zone.