Aerodynamic Optimisation and Exergy Analysis of a Conceptual Blended Wing Body Aircraft

The present work describes an aerodynamic optimisation study for a conceptual, blended-wing-body (BWB) in transonic, turbulent flow conditions. The flight point of interest is the aircraft cruise point of Mach 0.78 at 40000ft. The overall goal of this work is to refine the BWB aerodynamic design for subsequent engine integration and boundary layer ingestion (BLI) studies. In order to compare results with future BLI studies, an exergy analysis will be completed. An internal cabin volume constraint has been established and poses a challenge in terms of the aerodynamic performance of the aircraft. More precisely, the optimisation study tackles the compression/shock phenomena present at the cruise point. To improve the aerodynamic design, an Euler-based optimisation workflow is employed using the in-house ONERA CANOE tool. A detailed far-field drag breakdown of the flow solution is computed at the post-processing stage, providing access to the trade-off between the different drag components, in particular the wave drag. Sensitivity to angle-of-attack, angle-of-twist and local camber parameters are investigated. Finally, a RANSbased assessment of the aerodynamic performance of the optimised design is performed. In particular, as well as a far-field drag analysis, an exergy analysis [3] is performed using the ONERA ffx software. This initial optimisation work also serves to investigate the benefit of an exergy analysis approach before undertaking complex BLI engine integration analysis. The current work seeks to add relevant information to the currently available literature.