Electrochemical energy conversion offers the promise of clean, renewable power with minimal CO2 emission. Classical electrochemical energy systems include batteries and fuel cells. At LEMI we focus on the characterization and design of novel fuel cell systems. Current fuel cells of interest include proton exchange membrane fuel cells (hydrogen fed and direct methanol) and microbial fuel cells.
Experimental Investigation of Two Phase Flow in Direct Methanol Fuel Cells (DMFCs) -- Direct methanol fuel cells are promising energy conversion devices due to their low temperature operation and potential for high energy density. However, product carbon dioxide in the DMFC anode reduces active area, increases pressure load at the anode, and introduces instability to methanol delivery systems.
We have developed a novel experimental technique to characterize two phase flow in the DMFC anode. We have shown that in microscale DMFC anode flow channels (defined as channel dimensions on the order of the CO2 bubble detachment diameter) pressure drop scales with the number of gas slugs in the anode and capillary forces. Future work includes developing analytical solutions for simplified DMFC flow and in situ visualization of the DMFC anode during operation.
This work is beneficial for the design of miniature DMFC stacks for portable power applications.