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Abstract Water management is a critical issue to be solved efficiently for an air-breathing direct methanol fuel cell (DMFC). The cell performance decreases sharply once the water flooding occurs. In this paper, a novel strategy of water removal is proposed by incorporating a functional self-made expanded metal mesh, which can be used as the cathode flow field in a DMFC. Experiments show that water can be directly discharged in the form of water film or water line from the water outlet to the bottom underneath the expanded mesh. The water management can be further improved by using absorbent cottons, suitable feed rates and an upright texture direction of the metal mesh. Results also show that only a few mesh openings are blocked by water when the tested device tilts from 60° to 120°. In a real DMFC, the expanded mesh displays an excellent ability in water removal compared to the traditional perforated flow fields. The cathode water only gathers at the bottom and covers very few mesh openings. This new method helps efficiently avoid the issue of water flooding at the cathode using the expanded mesh. Highlights • Forced under-rib water removal by using metal mesh is proposed and validated. • Evolvement process of water passage is visually observed. • Improved methods for water management are investigated. • Generated water only gathers at the bottom and covers just a few mesh openings. • The issue of water flooding at the cathode is efficiently avoided in a real DMFC. [ABSTRACT FROM AUTHOR]

Management of the produced carbon dioxide (CO 2) is important to improve the performance of a liquid-feed direct methanol fuel cell (DMFC). This work investigates the CO 2 bubble behaviors and the two-phase flow characteristics, using a single sinusoidal corrugated channel as the anode flow field. The magnitude and gradient of the fluid velocity in this channel is higher than the traditional straight pattern, as proven by tracking CO 2 bubbles. The use of high magnitude and gradient of velocity enhances CO 2 emission and fuel delivery, as well as increases the pressure drop. The vortices in the disturbance structure of the corrugated channel help uniformly deliver the reactants and separate bubbles away from the channel wall. Using excessive values of amplitude A and angular frequency W in the corrugated channel causes serious bubble deformation and extra energy consumption. The effect of disturbance structure is negligible with small values of these two parameters. The cell with a corrugated channel shows a higher performance at different feed rates and concentrations of the methanol fuel. The optimal value of A and W are respectively 0.1and 5. The visualization tests demonstrate that the appearance of CO 2 bubbles in the corrugated channel is consistent with the simulation results. • A single-serpentine sinusoidal corrugated channel is used as the anode flow field. • Bubble behaviors are investigated by both simulation and visualization test. • The effects of two-phase flow characteristics on cell performance are studied. • The optimal parameters of amplitude A and angular frequency W are obtained. • The new flow field is preferred due to its functions in two-phase flow regulation. [ABSTRACT FROM AUTHOR]