Visualization of two-phase flow and temperature characteristics of an active liquid-feed direct methanol fuel cell with diverse flow fields

Direct methanol fuel cell (DMFC) is a promising power source for portable applications. This study aims to reveal the two-phase flow characteristics of an active liquid-feed DMFC by using the visualization method. Different flow fields based on the serpentine, parallel and porous patterns and their effects on reactant and product managements are experimentally investigated. Results show that the performance of serpentine flow field is closely influenced by the change of methanol feed rate but the parallel pattern shows less sensitivity. The use of serpentine flow field enables the fuel cell to be operated with a higher methanol concentration. A higher methanol feed rate promotes removal of the produced gas bubbles. The oxygen feed rate has a negligible effect on the fuel cell with a cathode serpentine flow field but produces a more obvious performance difference in the case of parallel pattern. The visualization tests indicate that the use of a higher oxygen flow rate is helpful in water removal. The temperature characteristics of the anode serpentine channel are evaluated and how the temperature behaviors relate to different operating conditions are accordingly discussed.