Overview
In aeronautics, gas turbine engines are equipped with lubrication systems whose function is to cool and lubricate the highly loaded rolling bearings and gearboxes.
The current trend of developing aircraft turbine engines that consume less fuel increases the cooling requirements from the lubrication systems due to higher speeds, loads and temperatures in engines as well as the integration of high-power gearboxes (allowing high by-pass ratio) and high-power starter-generators. For manufacturers there is significant pressure for developing new lubrication system architectures that are able to meet the new cooling and lubricating requirements without negatively impacting the mass of the systems or the operational and maintenance costs of engines.
Current lubrication systems in turbine engines are based on architectures and technologies that have not significantly evolved over the last thirty years. Despite improvements and advances made on components of these systems, the technological limit is being reached. In other words, new technologies are required to face the challenge of the future engine requirements: higher cooling, higher thermal efficiency, lower Specific Fuel Consumption ('SFC') impact, unchanged high-level of reliability, improved mass.
The main objectives of the project were to:
- Reduce engine SFC and related CO2 emissions by improving the bearing chambers and by improving the thermal management of bearing chamber housings and ports;
- Reduce engine oil consumption by 60%;
- Optimise the architecture and performance of lubrication systems and thereby reduce their complexity and mass;
- Develop solutions to improve monitoring of engine oil quality and prevent coking in the lubrication system.
ELUBSYS focused on new seal technologies (brush seals) that bear the promise of improving the propulsive efficiency of engines by reducing bleed air losses and that demonstrate the capability to withstand the harsh environment of aero engines.
These goals were to be achieved by a European consortium of Industry, Research centres, Academia and SMEs who set out to develop and validate these new lubrication technologies using modelling approaches and existing state-of-the-art test facilities.
ELUBSYS designed, developed and validated innovative technologies and architectures for aero-engine lubrication systems targeting increased efficiency and reduced cost, mass and engine Specific Fuel Consumption.
The primary focus was around new brush seal technologies that offer the potential to improve engine propulsive efficiency by reducing bleed air losses whilst withstanding the aero-engine's harsh environment.The project will investigate the performance and endurance of brush seals, assess their impact on the thermal efficiency of lubrication systems and their external components and on oil quality. A secondary focus is the wider lubrication system including vent, scavenge, bearing chamber modelling and oil behaviour.
Funding
Results
The following main results can be pointed out:
- The development of design rules in terms of housing architecture, heat management and associated external equipments that will lead to the implementation of advanced seals in aircraft engine lubrication systems;
- A simplified architecture for engine lubrication systems that results in fewer components and reduced mass;
- A set of design rules describing the way to develop more efficient bearing chambers, vent and scavenge pipes, seals and other external elements of the lubrication system; these rules have been derived from a combined effort of experimentation and advanced modelling techniques;
- Accurate methods and rules to predict heat transfer from the hot engine parts inside the lubrication system with a particular emphasis on bearing chambers;
- Accurate design rules for the design of external system (pipes, pumps) compliant with advanced housing architectures incorporating tight seals;
- Validated methods to predict and detect oil coking.
Policy objectives
Innovating for the future (technology and behaviour): A European Transport Research and Innovation Policy