The gas flow channels in fuel cells are responsible for distributing the reaction gases and water vapor to the gas diffusion layers. Additionally, they have to be designed in a way that condensed water coming out of the GDLs can be removed efficiently, thus leaving space for the gas phase and preventing local electrode flooding. Since the volume of liquid water in the flow channels is expected to be small compared to the gas volume, in the present model theliquid water is assumed to be in a dispersed state, which can be described with an average droplet diameter.