A mixed midelity conceptual design process for Boundary Layer Ingestion concepts

Summary

Boundary Layer Ingestion (BLI) is a promising concept that helps improving aircraft aeropropulsive performance. However, it remains difficult to bring together OAD (Overall Aircraft Design) process and high-fidelity tools due to the time of response of complex disciplinary tools. ONERA has thus developed a mixed fidelity approach inside its in-house OAD platform. The purpose is to mix conventional and robust OAD methods with high levels of fidelity from disciplinary tools such as CFD (Computational Fluid Dynamics), FEM (Finite Element Model) or CAA (Computational Aero Acoustics). This paper focuses on the integration of rapid CFD tools inside the OAD process, in order to assess BLI benefits. The resulting process is validated against reference and experimental cases when available, or high-fidelity RANS data elsewhere. The paper intends to present the tools and their validation process. These modules are applied to the common inlet concept, which aims at ingesting00% of the fuselage boundary layer. The results demonstrate the potential gain on the Power Saving Coefficient (up to 3% obtained with the L2 BLI module without resizing loop) but with non-negligible fan losses (up to 1.5%).

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