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Flow field design development using the segmented cell approach

Description: We report on fuel cell flow-field development employing two-dimensional computational fluid dynamics (2-D CFD). Simulation of the flow distribution of a parallel channel flow-field, with a simple one-channel manifold, predicted inhomogeneous performance distribution within the cell. Further modeling, focusing on modification of the inlet and outlet flow fields, was used to predict a more homogeneous flow distribution in the flow-field. Attempts were made to verify the theoretical predictions experimentally by application of the segmented cell system. Measurements of the current distribution and CO transient response supported the 2-D CFD predictions. However, the margin of error between predicted and experimental results was considered insufficient to be of practical use. Future work will involve the evaluation of 3-D CFD to achieve the appropriate level of accuracy.
Date: January 1, 2002
Creator: Bender, G. (Guido) & Ramsey, J. C. (John C.)
Partner: UNT Libraries Government Documents Department

Spatial distribution of the CO transient response of a PEFC

Description: We report on the investigation of the current distribution of a PEFC under the influence of CO impurities in the hydrogen feed stream by application of the segmented cell system. Stepping the CO partial pressure of the anode feed stream from 0 to 100 ppm CO the current response of the cell was recorded for different stoichiometric flows. A poisoning time delay occurs along the flow path due to the anode flow rate. Also anode and cathode processes, e.g. CO turnover and oxygen mass transport limitation contribute to the time response of the cell.
Date: January 1, 2002
Creator: Bender, G. (Guido) & Zawodzinski, T. A. (Thomas A.), Jr.
Partner: UNT Libraries Government Documents Department

Methanol crossover in direct methanol fuel cell systems.

Description: Direct methanol fuel cells (DMFCs) are currently being investigated for a number of different applications from several milliwatts to near kilowatt size scales (cell phones, laptops, auxiliary power units, etc .). Because methanol has a very high energy density, over 6000 W hr/kg, a DMFC can possibly have greatly extended lifetimes compared to the batteries, doesn't present the storage problems associated with hydrogen fuel cells and can possibly operate more efficiently and cleanly than internal combustion engines.
Date: January 1, 2003
Creator: Pivovar, B. S. (Bryan Scott); Bender, G. (Guido); Davey, J. R. (John R.) & Zelenay, P. (Piotr)
Partner: UNT Libraries Government Documents Department