Vision 20: Rolls-Royce's Long Term Civil Aircraft Propulsion System Concept and Technology Strategy

摘要

The Rolls-Royce 'Vision 20' strategy identifies novel engine, propulsor and airframe integration concepts that present the capability to significantly reduce aircraft fuel burn and environmental impact while meeting future market demands. It builds on the well-established near and medium term 'Vision 5' and 'Vision 10' programmes that include, in particular, the Rolls-Royce 'Advance' and 'UltraFan' projects. Current state-of-the-art in large turbofan fuel efficiency is represented by the Rolls-Royce Trent XWB. After introducing the Trent XWB and the novel features that contribute to its excellent fuelburn performance, the paper describes the Advance and UltraFan concepts Rolls-Royce is pursuing to develop novel core and propulsor architectures to deliver step change improvements in thermal and propulsive efficiencies. The UltraFan concept presents a similarly radical change to the configuration of the low pressure system, introducing a speed reduction power gearbox through which the fan is driven, that enables the fan and the turbine that drives it to be optimised independently. Rolls-Royce is developing both fixed and variable pitch variants of the UltraFan, and the respective merits and challenges discussed. Rolls-Royce has carried out a systematic process to determine long term demands of the civil air transport; to meet long term market demands and environmental targets, more radical airframe and propulsion system concepts will be required. Continued enhancement of both thermal and propulsive efficiencies will be necessary, with greater integration of airframe and propulsors, possibly with radical different airframe configurations. In the Vision 20 programme Rolls-Royce is investigating numerous novel core engine, propulsor and propulsion integration concepts. The most interesting will be discussed, including inter-turbine combustion, cryo-fuel heat exchange cycles, pressure-gain combustion and bottoming cycles, all aimed at improving thermal efficiency; integrated propulsion solutions involving boundary layer ingestion, multiple propeller systems, distributed and hybrid/electric propulsion aimed at improving propulsive efficiency are also be described.