Pursuing the conceptual proof, all main challenges associated with fuselage wake-filling propulsion integration in a turbo-electric PFC aircraft were tackled. A thorough understanding of the aerodynamic effects of 360° fuselage BLI was developed through extensive aero-numerical simulations and experimental testing in a laboratory environment. Optimised aerodynamic predesigns were produced for the BLI fuselage fan and the aft-fuselage section. Conceptual solutions for the aero-structural integration of the BLI propulsive device and the turbo-electric powertrain were elaborated. The developed design solutions have been either analytically or experimentally verified to demonstrate TRL 3 for the PFC technology. The CENTRELINE aircraft configuration was studied in low-speed wind tunnel experiments at relevant flow incidence angles. The 3D numerically designed fuselage fan was tested on a low-speed rig at relevant operating conditions. The scale-model experimental results were extrapolated to full speed and scaled based on extensive CFD numerical analyses. As such, initial steps towards experimental validation in a laboratory environment (TRL 4) have been taken. All detailed design and analysis results were incorporated in a multi-disciplinary PFC aircraft design optimisation. A roadmap for the future development of the PFC aircraft technology towards TRL 6 by 2030 has been devised in order to support a potential service entry of the PFC aircraft in 2035.
The PFC technology was rigorously benchmarked against a similarly advanced but conventional aircraft, the R2035. The PFC benchmarking covered aircraft-integrated performance and Cash Operating Cost (COC) assessments, as well as an evaluation against the environmental targets set by the ACARE Strategic Research and Innovation Agenda (SRIA) for the year 2035. Both aircraft, the PFC and the R2035 were pre-designed and sized to a realistic set of Top-Level Aircraft Requirements (TLARs) in accordance with common industrial practices in aircraft family design. The set of TLARs based on a future market analysis that showed a mid-to-long range air transport task featuring 340 passengers and 6500nmi design range to be the most impactful scenario.
The CO2 and NOx emissions of the turbo-electric PFC configuration were assessed based on an optimised 2D PFC aero-shaping, assuming Lean Direct Injection combustion technology for the year 2035 engines. Based on a fully integrated multi-disciplinary aircraft design and performance synthesis, the CO2 reduction of the turbo-electric PFC was determined to be -4.7% against the R2035 or -36% relative to the year 2000 SRIA baseline. The PFC NOx emissions during ICAO LTO cycle were assessed to be -1.8% versus the R2035. Cruise NOx emissions of the PFC aircraft were -20% relative to the R2035 and -64% when compared to year 2000. The equivalent perceived noise levels of the PFC aircraft according to ICAO certification were found to be similar to the R2035, meaning a cumulative noise reduction of 12EPNdB relative to a year 2000 aircraft. The design mission COC for the PFC aircraft was assessed to be lower than for the R2035 as soon as the fuel price increases beyond US$ 1.5 per gallon, even if fuel taxation or carbon pricing and offsetting cost for the year 2035 are neglected.
CENTRELINE partners disseminated results in 7 journals and participated at 9 conferences. A Policy Maker Workshop was organized (Brussels, 2019) and dedicated CENTRELINE sessions have been held at ISABE and EASN conferences (2019). At the EC Aerodays (Bucharest, 2019) the wind tunnel model and a section of the fuselage fan blading were displayed. An animation video and a mock-up, featuring the PFC technology, have been produced.
