Aerodynamic optimisation of a parametrised engine pylon on a mission path using the adjoint method

Abstract

The MDA–MDO project of IRT Saint-Exupéry aims at performing an aircraft engine pylon MDO. A bi-level formulation is enabling the reuse of the disciplinary optimisation software for aerodynamic, structure and OAD. This study focuses on the aerodynamics. A parametrised and differentiated CAD of the pylon has been developed. More than 400 variables are required to obtain an accurate shape of the pylon and to take into account of constraints. A challenge of the integration test case is the computation of intersection deformation. The process is differentiated to use the discrete adjoint of the CFD solver. First, an optimisation in cruise condition is performed. Then, operating conditions are added in the optimisation formulation. Finally, a trade off is performed with a DOE study on the engine position, where a local optimisation is performed for each of them. These results demonstrate the ability to handle the 3D pylon geometry with its intersections.