In Aeronautics, hydraulics energy is currently used for brakes, engine reverse system and flaps command. To significantly reduce weight, the major changes in the future will be: either an increase in the hydraulics pressure from 3000 Psi to 5000 Psi; or, an hybrid architecture electrical / hydraulics known as the EHA concept (Electrical Hydraulics Actuator), envisaged with possible increase of hydraulics pressure. For large aircrafts, the increase of pressure is studied in details and is planned in the future aircrafts. In parallel, the EHA concept may be used either in redundancy or complementary. For middle range aircraft, the EHA concept is nowadays preferred but the increase of pressure may be used in the future. The high-pressure technology is already applied in middle range military aircraft, and its civil application appears promising, stanting with the A380. In both cases, one of the key elements of the hydraulics circuit is the filtration function. Today most hydraulics filtration systems use renewable cartridges that are thrown away after use without the possibility of the incinerability or recycling. It is a highly polluting process, bearing in mind that hydraulics fluids are very chemically aggressive and hazardous to human health.


This project consists of working on future filtration requirements : use of more ecological material, improvement of cartridge lifetime and an increase in working pressure. The proposed approach is firstly to understand the physical mechanism of filtration by simulation. Theoretical models are proposed and then compared with experiments to obtain a high degree of confidence. New materials are studied, adapted and tested to fulfil performance requirements, most particularly incinerable conditions. Manufacturing processes are investigated for availability, cost impact and environmental constraints, and finally mock-ups are manufactured and tested to validate the technologies.