In Situ Two-Phase Flow Investigation of Proton Exchange Membrane (PEM) Electrolyzer by Simultaneous Optical and Neutron Imaging

Abstract

In PEM electrolyzers, oxygen evolution in the anode and flooding due to water cross-over results in two distinct two-phase transport conditions, and these two phenomena were found to strongly affect the performance. A comprehensive understanding of two-phase flow in PEM electrolyzer is required to increase efficiency and aid in material selection and flow field design. In this study, two-phase transport in an electrolyzer cell is visualized by simultaneous neutron radiography and optical imaging. Optical and neutron data are used as complementary to aid in understanding of the two-phase behavior. Behavior of gas bubbles is investigated and two different gas bubble evolution and departure mechanism is found. It is also found that there is a strong non-uniformity in the gas bubble distribution across the active area, suggesting the importance of the flow field design.