Research on Open Rotor Engines
DREAM Integrated Project delivers encouraging results
In the last 4 years, the DREAM EU-funded research project (valiDation of Radical Engine Architecture systeMs) has concentrated its efforts around innovative technologies for aeroengines and in particular on the open rotor architecture with potential fuel savings of up to 20% compared to state of the art turbofan.
The project was coordinated by Rolls Royce and gathered over 40 partners from industry, academia and research centers from Europe and beyond. The total cost of the project amounted to 40 MEur and the effort was equivalent to around 60 persons working full time during 4 years. The numerous project results were presented in the final workshop held in Derby 20-22 September in front of an attendance exceeding 100 participants.
Among the highlights, two open rotor configurations have been designed and tested at low and high speeds in large wind tunnels at DNW, ARA and Tsagi. While the expected fuels gains are confirmed, the challenge was to create low noise designs because the two contra rotating fans are generating noise and there is no nacelle to apply noise absorption materials. For this purpose, research centres and universities developed innovative analysis and design suites capable of handling such complex architectures, with the possibility to optimise the aerodynamic design in order to minimise the noise. Test results indicate that acceptable levels of noise can be achieved, below current ICAO standards. Findings are now taken up by the Clean Sky Joint Undertaking for large scale demonstration.
The project also developed a number of technologies that can be applied to classical turbofan engines such as, for example, an active control turbine clearance system allowing to achieve higher levels of efficiency, shorter and lighter ducts connecting the blade rows inside the engine with good aerodynamic performance or active vibration and noise damping systems that can be implemented on rotating fan blades for more silent engines.
Finally, after a thorough analysis of different types of alternative fuels and component tests, a 60 hours endurance test was carried successfully with a HVO fuel on a Turbomeca helicopter engine. With this, DREAM contributed significantly to the knowledge required by the international community to agree on common standards for aviation biofuels.
'In our view, such open rotor engines could be introduced as soon as 2027 on the market; without EU support, such an ambitious European collaborative project would not have been possible' concluded Nick Peacock, Director of Research and Technology at Rolls Royce.
Open rotor engine architecture investigated by Rolls-Royce
Airbus concept plane for a potential configuration of open rotor engines on an aircraft