The growth of Air traffic inevitably increases aviation's combustion and acoustic emissions, hence aggravating aviation's environmental impact locally and globally. HOPE will deliver an integrated aircraft propulsion system comprising two multi-fuel ultra-high bypass ratio (UHBR) turbofan engines, a fuel cell-based auxiliary propulsion and power unit (FC-APPU) driving an aft boundary layer ingestion (BLI) propulsor based on tube-wing aircraft configuration.
The HOPE system:
1)minimizes the combustion and noise emissions during landing and takeoff (LTO), hence the impact on air quality and noise annoyance near airports, without the trade-off of cruise emissions;
2)proposes a new propulsion system that avoids substantial changes to the aircraft planform, allowing integration into tube-wing configuration. Therefore, the substantial emission reduction is to be achieved within a short time;
3)reduces the risks associated with the introduction of 100% H2 propulsion systems (smaller hydrogen storage needed, reduction of instabilities related to lean combustion);
4)smoothens aviation’s energy transition through the assessment and exploitation of several greener propulsion technologies at different maturity levels.
HOPE emission goals consist of LTO NOx: -50%, CO: -50%, soot: -80%, perceived noise: -20% (~3 dB per operation), and climate impact: -30%, compared to state-of-the-art technology in 2020. To this end, HOPE will: 1)Design an integrated aircraft propulsion system accommodating multi-fuel (kerosene/sustainable aviation fuel +hydrogen) UHBR turbofan engines, FC-APPU, and an aft BLI propulsor; 2)Explore the novel idea of combining a BLI propulsor with FC-APPU for zero-emission taxiing; 3)Model, experiment, and demonstrate for the first time a low emission multi-fuel combustion technology burning H2+kerosene/SAF for future UHBR turbofan engine; 4)Assess societal impact, environmental burden, and cost benefits of the reduced noise and emissions by HOPE technology; 5)Formulate recommendations to introduce HOPE technology.
