3D numerical study of a flowing electrolyte - direct methanol fuel cell with an implemented bi-layered membrane electrode diaphragm assembly
In the present work, fluid dynamic simulation and experimental studies are compared to assess the validity of using computational fluid dynamics (CFD) to accurately predict the pressure losses experienced across each of the three fluid channels in a flowing electrolyte direct methanol fuel cell: methanol flow through anodicserpentine channels; air flow through the cathodic-serpentine channels; dilute sulfuric acid flow through the flowing electrolyte (FE) channel located between two membraneelectrode assemblies (MEAs). The methanol flow rate is varied from 5 to 25 mL/min and the airflow is varied from 0.5 to 5 L/min. The flowing electrolyte flow rate is also varied from 5 to 25 mL/min in order to analyze pressure levels within the FE channel, which, according to this analysis, must be larger than the adjacent serpentine channels. This pressure difference is particularly important to maintain the distance (and flow structure) between the MEAs without affecting performance of the fuel cell. Adequately controlling the pressure of each of three fluids disables the MEAs ability to deform without the use of an electrolyte spacer, effectively creating an inter-dependent bi-layered membrane electrode diaphragm assembly (Bi- MEDA). Through CFD simulation, it was observed that pressure equalization through the Bi-MEDA approach supports the elimination of a flowing electrolyte channel spacer from current FEDMFC designs. The reduction of the spacer is expected to decrease ohmic losses currently experienced in all FE-DMFC designs. Despite several approximations, simulations predicting pressure losses throughout the two serpentine fuel channels are compared against obtained experimental data, showing relatively good agreement for a single cell arrangement.
|Keywords||Direct methanol fuel cell, Flowing electrolyte, Methanol crossover, Pressure drop|
|Conference||ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology. Collocated with ASME 2011 5th International Conference on Energy Sustainability, FUELCELL 2011|
Cornellier, P.A. (P. A.), Matida, E, & Cruickshank, C. (2011). 3D numerical study of a flowing electrolyte - direct methanol fuel cell with an implemented bi-layered membrane electrode diaphragm assembly. In ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology. Collocated with ASME 2011 5th International Conference on Energy Sustainability, FUELCELL 2011 (pp. 703–709). doi:10.1115/FuelCell2011-54553