Based upon analysis of latest emission inventory data and current global market forecasts, important development trends in world region-specific air traffic growth and aircraft installed seat requirements are derived for the Propulsive Fuselage Concept (PFC) target Entry-Into-Service (EIS) year 2035. This is used to identify a most suitable market segment for the CENTRELINE technology to produce the greatest impact on overall air transport cumulative fuel

consumption.As a result, the cabin capacity and aircraft design range most appropriate for the targeted utilisation spectrum will be defined. A strategy for a product design family and associated aircraft build strategy is adopted allowing for margin of future potential stretch and shrink derivatives of the baseline aircraft. The aircraft application scenario also incorporates future passenger needs and behaviour.

In order to identify a best and balanced design solution from a number of candidate options a conceptual down-selection process will be employed. The decision-making is facilitated by a down-selection framework employing Pugh matrix scoring based on  

expert questionnaire. In a dedicated expert workshop, the concept options are rated with respect to a comprehensive set of multi-disciplinary criteria.The confidence level of expert decisions is gauged and supported by robustness evaluation techniques.

The aerodynamic design analysis work will be performed using problem-tailored numerical simulation methods for purposes of aerodynamic design space exploration and basic fuselage and aft-tip nacelle shaping, more detailed aerodynamic design and operational analyses of the pre-designed PFC aircraft and wind tunnel test campaign support, as well as fuselage propulsor design and performance analyses accompanying the BLI fan rig testing. For the design space exploratory work planned in the early phase

of the project, fast-responding methods coupling integral methods of potential and boundary layer flows are being used. The more detailed aero-numerical assessment of the overall configuration at on- and off-design conditions in are based on comprehensive 3D RANS simulations. For the detailed aerodynamic design and performance analysis of the fuselage propulsor, advanced high-fidelity (GPU-accelerated) 3D numerical simulations are performed.

For the turbo-electric drive train, electro-magnetic and mechanical simulations of the electric fuselage fan drive train will be performed together with thermal simulations of the associated motor cooling system. Therefore, CENTRELINE Partner in-house high-end finite element methods for mechanical, magnetic and thermodynamic computation are used. The predefined model structure in this setup allows for seamless exchange of models between multiple tools

that assess different disciplines. In that way, a “digital twin” model is created that is able to predict the impact of modifications from a mechanical, magnetic and thermal point of view without the need of translating the modified model for each tool. This approach significantly simplifies the optimisation of electric machines for minimum weight design.

For the sizing and performance synthesis of the CENTRELINE power plant systems, Partner in-house developed frameworks are employed. These offer comprehensive simulation capability for advanced engine architectures and allows predictions for engines subject to extensive power off-take. Power plant conceptual design, allowing the prediction of weight and component dimensions will be performed using a dedicated software developed primarily in the

FP6 projects VITAL (Contract no. AIP4-CT-2004-012271) and NEWAC (Contract no. AIP5-CT-2006-030876). Power plant system conceptual design follows a bottom-up approach where all the components are designed based on aerodynamic and mechanical first principles ensuring that the feasibility of the foreseen power extraction levels can be evaluated.

For the investigation of aero-structural design and integration aspects in T2.4, state-of-the-art commercial Finite Element Analysis (FEA) numerical methods are applied as evaluation basis for design refinement, eventually targeting component weight estimation. The structural analysis is being performed for the most critical load cases defined by CS-25 certification rules. Stress

analyses consider internal forces as well as external forces and moments acting on key structural components. The FEA stress analysis incorporates non-isotropic material properties as well as heat transfer implications of fuselage fan drive system on CFRP structures.

In order to provide robust design and performance guidelines for detailed numerical and experimental activities at an early project stage, in CENTRELINE, a rapidly responding aircraft conceptual design framework will be used. The framework had been tailored to fuselage wake-filling aircraft design tasks in the preceeding EC FP7 Project “DisPURSAL” and now serves as a strong support in the design decision making during the early phase of CENTRELINE. Over the course of the project the multi-disciplinary PFC aircraft  

design capabilities are being continuously extended and refined based on the results and findings obtained from CENTRELINE’s detailed design and analysis tasks. A common repository of all relevant system-level design and performance information including CAD data ensures maximum transparency and coherence at the different levels of design, simulation and experimentation throughout the collaborative project.

The core of CENTRELINE’s proof-of-concept for fuselage wake-filling propulsion integration is constituted by two experimental test campaigns aiming at obtaining a fundamental understanding of governing flow physics of both, the overall aircraft configuration and the fuselage BLI propulsor. For the overall configuration aero-validation testing in T3.1, a modular wind tunnel model is being developed and tested in the open jet facility (OJF) available at the Delft University of Technology. The wind tunnel model

design is based on the initial PFC design specified in work packages 1 and 2. An extensive test campaign is being conducted in the OJF in order to evaluate the performance of the concept. Particle Image Velocimetry (PIV) measurements are being taken and complemented by hot-wire measurements. The wind tunnel results will be post-processed and interpreted by experts to gain a fundamental understanding of the aerodynamic phenomena associated with the overall propulsive fuselage concept.

In order to verify the BLI fan aerodynamics of the PFC aircraft CENTRELINE utilizes the low-speed BLI Fan Rig facility in the Whittle Laboratory at the University of Cambridge. The advantages of this facility are that the fan can be run with any pattern and intensity of inlet stagnation pressure distortion representative of the flow field from the aircraft airframe entering the fan inlet. Full-annulus area traverses with a 5-hole pressure probe are possible at 5 traverse planes giving complete information on the 3D steady velocity and pressure fields (up to 20,000 measurement points

per traverse). Unsteady pressure measurements with up to 18 probes measuring simultaneously are also available for examining the rotor unsteady aerodynamic behaviour. The existing low speed BLI fan rig is being modified to match the CENTRELINE configuration: A baseline fan rotor and stator is being tested that is designed for uniform, clean inflow. This will then be modified based on the inlet flow-field for the CENTRELINE aircraft design operating at cruise.

A critical evaluation of the top-level properties of the final PFC aircraft design will be performed on a multi-disciplinary assessment platform. This enables concept benchmarking with regards to key

environmental targets,such as the CO2, NOx and noise reduction goals set by the ACARE’s Strategic Research and Innovation Agenda (SRIA).