A Slope Right‐angle Turn Applied in the Flow Channel Promotes Water Management in Proton Exchange Membrane Fuel Cells

Abstract

Effective water removal and transport in the flow field is significantly important to the critical water management in proton exchange membrane fuel cells (PEMFCs). In this work, a slope turn was proposed in the hydrophobic channel of the multi‐serpentine flow field, and the transport and dynamics of water in the modified flow channel were numerically investigated with the volume‐of‐fluid method. The simulation results indicated that, with the presence of the slope turn, the water droplet can be effectively detached from the surface of the gas diffusion layer although the channel walls are hydrophobic. Meanwhile, the hydrophobic channel walls are beneficial to decrease interfacial resistance of water transport, avoiding water accumulation in the flow channel. The wall contact angle, slope angle and gas flow velocity are three important factors which significantly affect water behavior and pressure drop in the flow channel. For considered cases in this work, the appropriate wall contact angle, slope angle, and gas flow velocity were proved to be 140°, 110°, and higher than 2 m s−1, respectively.

A Triple Bioinspired Surface Based on Perfluorodecyl Trimethoxysilane-Coated ZnO Nanosheets for Self-Driven Water Transport in a Flow Channel

“…Among these factors, water management is an important issue to improve the performance of PEMFCs . The main reasons are as follows: on the one hand, a certain amount of water must be maintained inside the PEMFC to ensure that the proton-exchange membrane has favorable proton conductivity. , On the other hand, excessive water should be drained out of the PEMFC to prevent water flooding, which could impede gas transfer to the catalytic layer and impair normal electrochemical reaction. Hence, various investigations have been conducted to change the wettability of the channel in the bipolar plates of the PEMFC to achieve optimal water removal …”