DGLR-Publikationsdatenbank - Detailansicht
F. Oehme, S. Kabelac
In order to fulfil the Vision 2020 - emission reduction aims, which the aviation industry imposes upon itself, the design of a multifunctional fuel cell system (MFFCS) in passenger aircrafts is investigated. The MFFCS is developed as a highly integrated system which replaces the auxiliary power unit. Besides the electrical power, all side products of the MFFCS as water, oxygen depleted air and waste heat should be used for different applications within the aircraft. The water vapour from the cathode outlet air is liquefied inside the dehumidifier and fed to the water supply system. In Fig.1 the fuel cell stack, the air-compressor and the dehumidifier of the MFFCS is shown. For the system operation a maximum oxygen and water vapour content for the oxygen depleted air are specified. To fulfil these requirements a hybrid dehumidifying solution seems likely. Therefore different dehumidifying concepts need to be compared against each other. In this work the focus will be on the cooling below the dew point with a liquid cooled heat exchanger. A simulation model of a tube fin heat exchanger is developed in Matlab/Simscape. The model can be used as a cell model for an improved fitting to correlations for the air-side heat transfer coefficient and the mean temperature difference. Furthermore experiments were conducted to validate the simulation results with experimental data. It is shown that the heat flow deviate from the simulations up to 30%. However the k A-factor shows compliance within 2% without and 15 % with partial condensation.
Deutscher Luft- und Raumfahrtkongress 2012, Berlin
Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn, 2013
21,0 x 29,7 cm, 10 Seiten
Stichworte zum Inhalt:
Brennstoffzelle, Entfeuchtung, feuchte Luft, gekoppelter Stoff- und Wärmeübergang, Partialkondensation, Wärmeübertrager