A numerical investigation of operating condition effects on unitized regenerative fuel cells with elliptically shallow channel during mode switching

Abstract

ABSTRACT In this study, a two-dimensional, two-phase, non-isothermal, and un-steady state unitized regenerative fuel cell model is established. The effect of various operating conditions on the variation trend of parameters and cell performance during mode switching from fuel cell to electrolytic cell mode is studied when using an elliptically shallow flow channel. Three operating parameter conditions are discussed, including inlet gas velocity, electrolytic cell voltage and water supply velocity. The effects of various operating conditions on cell performance and parameters are compared. The results show that different operating conditions have different effects on cell performance. When switching from fuel cell mode to electrolytic cell mode, changing the stoichiometric ratio of inlet gas velocity does not affect the cell performance after mode switching. The cell performance can be improved gradually with the increase in electrolytic cell voltage. Increasing the flow rate of liquid water can effectively speed up the stabilization time, however, the cell performance is slightly reduced, and it is easy to accumulate oxygen at the outlet.