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ISSN Online: 2377-424X

ISBN CD: 1-56700-226-9

ISBN Online: 1-56700-225-0

International Heat Transfer Conference 13
August, 13-18, 2006, Sydney, Australia

HEAT AND MASS TRANSFER CHARACTERISTICS IN A FREE BREATHING FUEL CELL WITH A DUCTED CATHODE

Get access (open in a dialog) DOI: 10.1615/IHTC13.p24.200
12 pages

Résumé

Free Breathing-Proton Exchange Membrane Fuel Cells (FB-PEMFCs) absorb oxygen from atmospheric air by natural convection and avoid the use of auxiliary equipments required for oxidant supply. Analysis of the heat and mass transfer characteristics in such fuel cells is essential as the performance is strongly influenced by free convection mass transfer which also depends on the cathode design. This paper reports a 2-D, steady state, single phase and non-isothermal cell model for FB-PEMFC with a vertical ducted cathode design and predicts the heat and mass transfer characteristics in Membrane Electrode Assembly (MEA), cathode Gas Diffusion Layer (GDL) and cathode duct of the fuel cell. The mathematical model representing the complex phenomena of combined heat and mass transfer with multi-component transport, flow through porous medium and electrochemical kinetics is solved by the Finite Volume Method (FVM) using FLUENT 6.1 incorporated with User Defined Functions (UDFs). The effect of atmospheric operating conditions on the performance is also studied. The polarization curve predicted by the model is in good agreement with the only reported experimental data. The model predictions for the voltages at low current densities are accurate. The average free convective mass transfer coefficient based on mean mass fraction in the duct as reference is found to be of the order of 10−2 m/sec. The temperature rise of free convective air in the duct is about 2 to 3°C indicating the limitation of natural cooling at high operating current densities. The operating atmospheric temperature has significant effect on the performance of the fuel cell while the effect of atmospheric relative humidity is negligible.