PEMFC application for aviation: Experimental and numerical study of sensitivity to altitude

Proton Exchange Membrane Fuel Cells are more and more considered as energy converters for mobile applications, such as road vehicles, boats and airplanes. The feasibility of PEMFC integration to aircraft raises several difficulties such as the loss of performance due to altitude and ambient pressure decrease. obic PEMFC system is experimentally investigated at three different altitudes representative of aircraft cruise (200 m, 1200 m and 2200 m), and at different air stoichiometric factors (from 1.5 to 2.5). The experimental results are employed to perform fitting of PEMFC numerical model parameters and validation of the model. A least square method is implemented in a Matlab® code to determine one set of model parameters for all experimental data sets. The model based on literature is modified in order to better represent the effect of ambient pressure on voltage response. Comparisons of experimental and numerical results are presented and show good agreement. Fuel cell performance is found to decrease drastically as altitude increases, as well as air stoichiometric factor decreases. The air pressure in cathode gas channels is measured and analysed. The decline of PEMFC performances in altitude is due to ambient pressure decrease, to air compressor efficiency drop and to flooding in the gas channels. This PEMFC loss of performances is attenuated by high cathode stoichiometric factors.