CO₂ bubble behaviors and two-phase flow characteristics in single-serpentine sinusoidal corrugated channels of direct methanol fuel cell

Management of the produced carbon dioxide (CO₂) is important to improve the performance of a liquid-feed direct methanol fuel cell (DMFC). This work investigates the CO₂ 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 CO₂ bubbles. The use of high magnitude and gradient of velocity enhances CO₂ 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 CO₂ bubbles in the corrugated channel is consistent with the simulation results.