Liquid water preferential accumulation in channels of PEM fuel cells with multiple serpentine flow fields

•Neutron imaging was used to visualize liquid water distribution in PEMFC channels.•Preferential water accumulation in certain channels was observed for all conditions.•Gravity, flow direction and channel position were determining water accumulation.•Channels with upwards gas flow showed much higher water accumulation.

This work presents an experimental investigation on the preferential accumulation of liquid water in the channels of a multiple serpentine PEMFC with 50 cm2 active area. Neutron imaging was used for visualizing the liquid water distribution during the cell operation for a wide range of operating conditions. Liquid water accumulation in the cathode channels was observed for most of the operating conditions, with a preferential accumulation in certain channels of the flow field. A statistical analysis was performed in order to determine the main characteristics of this accumulation (i.e. channel number and degree of accumulation). As cathode channels were positioned in vertical direction, it was found that gravity effects had an important influence in the accumulation, as well as the relative position of the channel with respect to the inlet and outlet locations. The gas flow direction had also a major impact on the water accumulation within the channels, with significantly more water accumulated in channels with upwards gas flow.