This proposal responded to the call JTI-CS-2012-1-SGO-02-040, in the Clean Sky Joint Undertaking included in the frame of the European FP7. This call was made for the design of a filtration system for electrical ECS (Environmental Control System) packs.
Traditional ECS packs take the air from the engine through the bleed system. Therefore, some previous filtration is performed, since the air has gone through several stages of the engine compressor. Contrary, electrical ECS packs capture directly the air from the atmosphere via the scoop air inlet located on the belly fairing of the aircraft. Consequently, pollutants can be ingested by the scoop and therefore be introduced in the compressor of the electrical ECS if the air inlet is not properly cleaned.
Most of aircrafts are equipped with traditional bleed ECS packs. Nevertheless, Boeing has incorporated such electrical no-bleed systems on the Boeing 787. Furthermore, applicability of actual filtration technology used on aircrafts and rotorcrafts highly exposed to harsh environment has to be further investigated and analysed. Such systems are basically barrier filtration or inertial particle separation filters.
Thus an air filtration system had to be developed during the project to accomplish the required removal of debris and pollutants at the compressor inlet. The aim of the filtration system was at the end to guarantee that the probability of loss of fresh air supply to the cabin stays in a non-relevant range, according to ECS safety.
The methodology proposed combines theoretical (computational) and experimental techniques, and the knowledge in fluid dynamics by UPVLC with the industrial experience of LBFS in this particular area. Furthermore, applicants have wide experience managing performing EU funded projects and private funded projects for the development of filtrations systems in different industrial areas.
ELECFILTER had been a 21 months project to develop the filtration system of compressor air inlet protection for Electrical ECS. All the Work-Packages and the corresponding tasks were carried out following the project planning. Furthermore, all the Deliverables were available on time, including the final demonstrator delivered in June’14.
A complete review of the state of the art about anti-FOD and filtration systems had been carried out.
CFD methodology (mesh independence, turbulence, boundaries, solver…) was also developed for the computational analysis of the flow (air + particles) around the scoop and inside the system. Different approximations had been taken into account for the scoop simulations. On one side, real flight conditions including the fuselage of the aircraft had been analysed, on the other side, simplified Test Cell conditions in order to study the validity of such Test Cells and its influence on the flow features inside the scoop.
A deep analysis of the main flow phenomena had been performed by means of the CFD calculations.
Computational and experimental tests were carried out with some current feasible solutions to be applied or adapted to ELECFILTER
A multi-stage (x4) filtration system had been developed and optimised as solutions for ELECFILTER. These 4 stages are: (1) Pre-filtering protection flap, (2) Inertial Separator, (3) Coalescence media and (4) Barrier media filter.
Finally, the ELECFILTER demonstrator had been manufactured and delivered as final result of the project. This prototype was used to confirm the key characteristics: weight, pressure drop and filter life as post-project activity.