Abstract
In order to collect fundamental design data concerning CO_2 removal, the authors have concentrated on CO_2 bubble behavior, which dominates anode mass transport in a fuel supply subsystem, especially in anode gas diffusion layers (GDLs). Firstly, effects of fuel supply structure with anode gas diffusion layers (GDLs) on CO_2 bubble release was investigated by visualizing CO_2 bubble behavior in anode GDLs with visual passive DMFC modules. Secondly, effects of CO_2 bubbles on fuel tank pressure was investigated with pressurized passive DMFC modules by changing anode GDL wettabilities parametrically. Consequently visual passive DMFC modules revealed the followings; (1) CO_2 bubble behavior was mainly dominated by GDL wettability, not fuel supply structure, (2) hydrophobic anode GDLs (contact angles, 128°) caught CO_2 bubbles on their surfaces, but hydrophilic anode GDLs (contact angles, 47°) set free CO_2 bubbles from their surfaces. Furthermore, pressurized passive DMFC modules elucidated that the total volume of CO_2 bubbles present in a fuel tank increased fuel tank pressure, and prevented CO_2 and methanol from transferring in anode GDLs. These results made it clear that CO_2 release was promoted by hydrophilic anode GDLs, but not by hydrophobic ones. In other words, selection of GDL wettability determined CO_2 bubble release characteristics regardless of fuel supply structure.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
