CO2 bubble behavior in the anode flow field of a transparent Direct Methanol Fuel Cell (DMFC) was investigated visually. The DMFC consisted of a membrane electrode assembly (MEA) with an active area of 4.0×4.0 cm2, two transparent enclosures made of Lucite material, and two bipolar plates made of 316 stainless steel plate, in which a single 2.0×2.0 mm2 serpentine channel having a total length of 420 mm was formed. An image recording system was employed to capture images of the two-phase flow behavior in the anode flow field. It is found that at low current densities, small discrete bubbles appeared in the anode flow field. At moderate current densities, a number of gas slugs formed in addition to small discrete bubbles. At high current densities, the flow field was predominated by rather long gas slugs. The effects of methanol solution flow rate, cell operating temperature, and methanol concentration on the CO2 behavior and the cell performance have also been investigated. Furthermore, for the present flow field consisting of a single serpentine channel, the phenomenon of big CO2 gas slugs blocking the channel was never found for all the test conditions in this work.

This content is only available via PDF.
You do not currently have access to this content.