Abstract:

A transparent PEM single cell with a single straight channel was used to investigate the liquid water transport in the cathode channel.The direct relationship between liquid water removal and pressure-drop between inlet and outlet of the channel was obtained.A diagnostic method was developed to evaluate liquid water accumulation and removal in the channel by combining visualization and pressure-drop measurement.With the increase in humidification temperature, the region of liquid water extended from the lower part of the channel towards the inlet.For a given flow channel, there was a specific velocity, at which the droplet critical diameter was comparable with the channel size and liquid water accumulation in the channel was the highest.Under the study conditions, the specific velocity was 2 m·s^-1.To discharge the liquid water in time, gas velocity should not be lower than 3 m·s^-1.

Key words:

可视化PEMFC, 压降, 水淹, 水分布, 排水

摘要：

通过直条单流道可视化PEM单池研究了阴极流道内液态水的传递行为，给出了液态排水与流道进、出口压降间的直接关系。结合可视化与压降测量，开发一种评价流道内液态水积累及排出的新方法，考察了增湿温度与气体流速对流道内液态水分布及排水的影响。随着增湿温度提高，存水区域由流道下部向进口扩展。对于给定流道，存在一特定流速。在该流速下液滴临界直径与流道尺寸相当，流道内液态水积累最严重。在本实验条件下，该特定流速为2 m·s^-1。为了及时排出液态水，气体流速不能低于3 m·s^-1。

关键词:

可视化PEMFC, 压降, 水淹, 水分布, 排水