Minimizing aircraft ECS bleed off take using system simulation.

This paper presents the activities foreseen on the Finmeccanica EIS 2020 derivative aircraft performed in the frame of the FP7 European research project TOICA. On board air systems for conventional aircrafts are fed by the bleed off-take which penalizes the amount of power available to the power of jet turbine or turboprop engines. In order to minimize such operating penalties and optimize the energy efficiency of the overall aircraft, it is of major interest to support trade-off at aircraft level including aircraft systems as early as possible in the development cycle. The study presents the complete methodology and associated simulation activities relying on the system simulation platform LMS Imagine.Lab Amesim. Several aircraft configurations and ECS pack architectures are studied. From the very beginning of the design cycle, the requirements and the objectives for the air conditioning system are completed with thermal requirements by performing thermal evaluations of the fuselage. Pre-sizing of every ECS pack component is achieved. Then, the resulting ECS packs are integrated with the engine bleed air system and the thermal model of the aircraft structure including the different heat loads, passengers and electronic equipment mainly. The integration is assessed over complete flight missions allowing to validate the steady state ECS performances, the transient pull up and pull down scenarios as well as the overall engine bleed off-take and energy balance. This trade shows that the 4 wheel bootstrap fulfilled the requirements contrary to the 3 wheel bootstrap which failed to cool down the cabin.