Analysing Gas-Liquid Flow in PEM Electrolyser Micro-Channels

PEM water electrolysis is a key component for closing the loop of the renewable energy eco-system. In particular, these high response water electrolysers are suitable for fluctuating power sources. Conventional PEM water electrolysers are typically operated at a current density of around 1 A/cm(2) and are fairly expensive. One means of increasing the hydrogen yield to cost ratio of such systems, is to increase the operating current density. However, at high current densities, management of heat and mass transfer in the anode current collector and channel becomes crucial. This entails that further understanding of the gas-liquid flow in both the porous media and the channel is necessary for insuring proper oxygen, water and heat management of the electrolysis cell. In this work, the patterns of vertical upward gas-liquid flow in a 5x1x94 mm micro-channel are experimentally analysed. A sheet of titanium felt is used as a permeable wall for permeation of air through a column of water similar to the phenomenon encountered at the anode. The transparent setup is operated ex-situ and the gas-liquid flow regimes are identified using a camera.