Combustion noise is increasing its relative contribution to aircraft noise, while other sources are being reduced and new low-NOx emission combustion chambers being built. Two mechanisms are responsible for this noise source: direct noise in which acoustic waves are generated by the flame and propagate to the outlet of the aero-engine, and indirect noise, where entropy waves generate noise as they are accelerated and decelerated in the turbine stages. In this work, the analytical models used for the propagation of waves through non-homogeneous flows, including the generation of indirect noise, are revised and extended. In the first part, the quasi-1D case is studied, extending the analytical method to non-zero frequencies and validating the results with numerical methods and experimental data. In the second part, the 2D method for the case of compact turbine blades is studied and validated using numerical simulations of a rotating blade and of a complete turbine stage. Finally, in the third part of this thesis, these models are combined with reactive and compressible Large Eddy Simulations (LES) of combustion chambers to build a hybrid approach, named CHORUS, able to predict combustion noise.
Keywords: Combustion noise, indirect noise, aero-acoustics, analytical methods.
Members of the Jury :
Friedrich BAKE DLR, Deutchland Member
Sébastien DUCRUIX CENTRALE SUPELEC, France Referee
Aimée MORGANS MPERIAL COLLEGE LONDON Member
Franck NICOUD UNIVERSITE DE MONTPELLIER, FRANCE Referee
Maxime HUET ONERA, PALAISEAU Advisor
Stéphane MOREAU SHERBROOKE UNIVERSITY, CANADA Co-Advisor
Laurent GICQUEL CERFACS, FRANCE ADVISOR