2.1 Introduction

The ANSYS FLUENT Fuel Cell and Electrolysis Model is comprised of several user-defined functions (UDFs) and a graphical user interface. The potential fields are solved as user-defined scalars. The liquid water saturation, $s$, and the water content, $\lambda$, are also solved as user-defined scalars. The electrochemical reactions occurring on the catalyst are modeled through various source terms while other model parameters are handled through the user interface. The Fuel Cell and Electrolysis Model can be used in parallel ANSYS FLUENT as well.