Overview
At the time of this project air traffic growth (5% growth rate per annum according to ICAO) was greatly impeded by the noise generated by aircraft as well as the harmful effects of aircraft pollutants on the environment (3% growth in CO2 emissions per annum). Aircraft engines are a large source of CO2 and NOx emissions and contributors of noise. The quantity of these gases emitted into the atmosphere is controlled by operational factors as well as engine and aircraft design technologies. This is why the engine is judged to require a further 20% CO2 reduction when the ACARE SRA requires a 50% reduction by 2020.
Consequently, Europe's aviation industry faces a massive challenge to satisfy the demand whilst ensuring economic, safe and environmentally friendly air travel. Radical and innovative engine structures and architectures werre investigated in order to meet these extremely challenging targets for acoustics and pollution. Such reductions could only be achieved by reconsidering completely, in a first step, the different components of an engine with innovative breakthrough designs, and in a second step, by assembling and optimising these components in new engines.
VITAL provided a major advance in developing the next generation commercial aircraft engine technologies, enabling the European aero-engine industry to produce high-performance, low-noise and low-emission engines at an affordable cost for the benefit of their customers, air passengers and society at large.
The main objective of VITAL was to develop and validate engine technologies that provide:
- 6 dB noise reduction per aircraft operation and equivalent to a cumulative margin of 15-18 EPNdB on the three certification measurement points and
- 7% reduction in CO2 emissions.
This is with regard to engines in service prior to 2000.
VITAL integrated the benefits and the results of ongoing research projects with regard to weight reduction (EEFAE) and noise reduction (SILENCE(R)) technologies, assessed at a whole engine level their benefits and combined their outcomes with those of VITAL to enable, by the end of the project in 2008, the following:
- 8 dB Noise reduction per aircraft operation (cumulative ~24 EPNdB on the 3 certification measurement points) and
- 18% reduction in CO2 emissions.
The objective of VITAL was achieved through the design, manufacture and rig-scale testing of the following innovative technologies and architectures:
- two innovative low-speed fan architectures for (1) Direct Drive Turbo Fan (DDTF) and Geared Turbo Fan (GTF) and (2) Contra-Rotating Turbo Fan (CRTF). This included intensive use of lightweight materials to minimise the weight penalty of Very High Bypass Ratio (VHBR) engines;
- new high-speed and low-speed low-pressure compressor concepts and technologies for weight and size reduction;
- new lightweight structures using new materials as well as innovative structural design and manufacturing techniques;
- new shaft technologies enabling the high torque needed by the new fan concepts through the development of innovative materials and concepts;
- new low-pressure turbine technologies for weight and noise reduction, suited to any of the new fan concepts;
- optimal installation of VHBR engines related to nozzle, nacelle, reverser and positioning to optimise weight, noise and fuel burn reductions.
All these technologies were evaluated through preliminary engine studies for the three architectures, DDTF, GTF and CRTF.
To achieve the VITAL objectives, different modules of an engine were considered, some generic and usable in all three engine types, while some others were specific. Consequently, the work in VITAL was organised into seven technical sub-projects and one sub-project (Sub-Project 0) for management and dissemination activities. The technical sub-projects were split according to each part of the engine. A transversal sub-project (Sub Project 1) ensures that the module is well integrated by:
- defining module requirements and
- assessing the three main engine architectures: DDTF, GTF and CRTF.
VITAL researched, designed and developed technologies regarding:
- innovative fan design (lightweight fan and contra fan technologies) - Sub Project 2;
- high-load booster design and technologies - Sub Project 3;
- lightweight hot and cold structures - Sub Project 4;
- novel materials and concept for low-pressure engine shafts - Sub Project 5;
- high-loaded and high-lift low noise and lightweight, low-pressure turbines - Sub Project 6;
- nacelle design and aircraft installation - Sub Project 7.
Funding
Results
The project results included:
- two fully instrumented fans (DDTF & CRTF);
- a fan rotor, a fan casing and a structural fan stator;
- two low-pressure compressor boosters (low-speed and high-speed);
- new lightweight materials and material forms (polymer matrix composites and titanium);
- composite high torque shafts;
- turbines for DDTF/GTF applications;
- nozzle installation under the wing and
- guidelines for the development of 2020 engines.
Technical Implications
The VITAL and concurrently, the ACARE 2020 objectives, cannot be reached through the improvement of existing proven technologies. Breakthroughs are needed in the design of engines and in the technologies used in the various components. This was achieved in VITAL by developing a new set of technologies for producing a very high By-Pass Ratio (BPR) engine, reducing noise emissions and fuel consumption from engines and avoiding or minimising the drawbacks of engine drag and weight associated with low specific thrust engines. VITAL focussed on Low Pressure parts and installation.
The project aimed to develop these new technologies through:
- New fan concepts with the design of two types of fans: counter-rotating and light-weight fans.
- New booster technologies: high load boosters, low speed and high speed, associated aerodynamics technologies and new lightweight materials.
- 30% weight saving in the engine structure through the use of polymer composite and corresponding structural design and manufacturing techniques.
- 50% torque capability without weight impact of the shaft through the development of innovative materials TiMMC shaft (Titanium Metal Matrix Composites) and Multi Metallic Shaft with associated concepts.
- 20% weight saving in the low-pressure turbine through innovative ultra high lift airfoil design, ultra high stage loading, lightweight materials and design solutions and low noise design measure.
- Optimal installation of high BPR engines related to nozzle, nacelle, reverser and positioning to optimise weight, noise and fuel burn reduction.
The VITAL technologies were tested and validated using major aerodynamic, acoustic and mechanical rig tests throughout the project lifetime. They provided a validated set of engine technologies and integrated research infrastructure supported by a validated exploitation plan for the use of these technologies in a next generation low-noise, cost-efficient engines.