Sensitivity of Boundary Layer Ingestion Effects to Tube and Wing Airframe Design Features

Conceptual design of boundary layer ingesting (BLI) aircraft requires a methodology that captures the aero-propulsive interactions in a parametric fashion. This entails modeling the impacts of BLI as a function of the airframe and propulsor design. Previous work has analyzed the sensitivity of these BLI effects to the propulsor size and throttle. This paper assesses the sensitivity of the BLI effects to the airframe design through a series of experiments, using CFD. The scope of this analysis is restricted to tube and wing type BLI concepts. Results from these studies help identify the critical airframe design space that needs to be considered when generating a parametric model of the BLI effects. Guidelines regarding the level of detail required for the airframe geometry model are discussed

Exergy-Based Formulation for Aircraft Aeropropulsive Performance Assessment: Theoretical Development

International audienceAircraft have evolved into extremely complex systems that require adapted methodologies and tools for an efficient design process. A theoretical formulation based on exergy management is proposed for assessing the aeropropulsive performance of future aircraft configurations. It consists in the combina-tion of a momentum balance and a fluid flow analysis involving on the first and second laws of thermo-dynamics. The exergy supplied by the propulsion system and its partial destruction within the control volume is associated with the aircraft mechanical equilibrium. Characterization of the recoverable mechanical and thermal outflows is made along with the identification of the irreversible phenomena that destroy their work potential. Restriction of the formulation to unpowered configurations yields connections to some well-known far-field drag expressions and shows that their underlying theory can be related to exergy considerations. As the exergy balance does not rely on the distinction of thrust and drag, it is especially suitable for the performance evaluation of highly integrated aeropropulsive concepts like boundary layer ingestion

Numerical Airframe Aerodynamic Performance Prediction: An Exergy Point of View.

The prediction of the aerodynamic performance of airframe has been historically made via the determination and decomposition of the force opposing the aircraft motion: drag. The paper presents an innovative energy approach which is based on the destruction of exergy by irreversible processes. A required step in the development process is to validate its numerical implementation via various CFD test cases: 2D aerofoil and 3D wing RANS test cases are presented in subsonic and transonic regimes. Mesh convergence studies prove the exergy approach to have a similar accuracy as the traditional near-field drag approach while offering a phenomenological breakdown comparable to a far-field formulation

Experimental Investigations on Common Research Model at ONERA-S1MA–Drag Prediction Workshop Numerical Results

International audienceThis paper aims to present some of the experimental and numerical results obtained with the NASA–Boeing Common Research Model at ONERA. The wind tunnel model used in the present study is the ONERA Large Reference Model (1/16.835), which has the same geometry as the Common Resarch Model considered in the latest AIAA Drag Prediction Workshops. Experimental data have been collected from the ONERA-S1MA wind tunnel at Mach numbers between 0.30 and 0.95 and a mean aerodynamic chord Reynolds number of 5 million for four different configurations: wing/body only and wing/body with horizontal or vertical tails or both. Force and moment and pressure and surface flow measurements have been performed. Concerning the numerical study, all the Reynolds-averaged Navier–Stokes computations have been completed with the structured solver elsA, and the Spalart–Allmaras and kω with shear stress transport turbulence models have been used in addition to the quadratic constitutive relation. In this paper, configuration effects (increments due to horizontal and/or vertical tails) are assessed both numerically and experimentally for several Mach numbers and angles of attack. The delicate issue of flow separation at the wing/body junction is also addressed with the support of oil flow visualizations. elsA and S1MA skin pressure distributions are presented; the agreement is satisfactory except for some outboard wing sections at high lift levels. Finally, comparisons of drag and moment values including computational fluid dynamics and test data from different wind tunnels are proposed (S1MA, NASA Ames Research Center and National Transonic Facility, and European Transonic Wind Tunnel)

A Concept Plane using electric distributed propulsion Evaluation of advanced power architecture

International audienceStarting from electrical distributed propulsion system concept, the ONERA’s engineers demonstrated the viability of an all electrical aircraft for a small business aircraft. This paper describes the advanced power architecture considering energy conversion and power distribution. The design of this advanced power architecture requires the multi-physic integration of different domains as flight performances, safety and environmental requirements (thermal, electric, electromagnetic). From this analysis, all components of this advanced power architecture have been identified and evaluated

Exergy-based Aircraft Aeropropulsive Performance Assessment: CFD Application to Boundary Layer Ingestion

International audienceAircraft have evolved into extremely complex machines that require adapted tools to allow efficient design process. A performance formulation based on an exergy balance is under development at ONERA for assessing future aircraft configurations. A control volume analysis is performed to relate the exergy supplied by the propulsion system, its partial destruction within the control volume and the aircraft mechanical equilibrium. The formulation does not rely on the expression of thrust and drag and is therefore especially suitable for the performance evaluation of blended-wing bodies with boundary layer ingestion. A first step towards such applications is the investigation of a more academic configuration consisting in the ingestion of the complete wake of a simplified fuselage. Investigation is made via 3D RANS computations and it is shown that the benefit is due to lower levels of exergy destruction in the wake/jet of the BLI configuration

Preliminary design of next generation Mach 1.6 supersonic business jets to investigate landing & take-off (LTO) noise and emissions - SENECA

With the approach of next generation supersonic transport entry into service, new research activities were initiated to support updates on ICAO regulations and certification processes for supersonic transport vehicles. Within this context, the EU Horizon 2020 SENECA project has been launched to investigate the levels of noise and gaseous emissions in the vicinity of airports as well as the global climate impact of next generation supersonic civil aircraft. This paper introduces some of the preliminary outcomes of this investigation. It presents the preliminary design and performance analysis of a Mach 1.6 business jet, following an integrated aircraft-engine design approach. The preliminary design was performed accounting for the limitations posed by future environmental restrictions on respective subsonic vehicles. The market space and mission route definition exercise assumed only "over-sea"supersonic operations, while for "over-land", only subsonic operations where allowed. Parametric studies on engine integrated design demonstrated modest core temperatures while cruising and the significant impact of engine installation on performance. At this first design iteration, assuming current state of the art technology, the Mach 1.6 business jet showed good potential to satisfy the predicted mission requirements while respecting the environmental constraints in terms of Landing & Take-Off (LTO) noise and emissions