PhD defense - G. Boudier

in helicopter gas turbines

(Confidential)

Delivered by INP Toulouse
Speciality: Fluid dynamics

December 10, 2007 - CERFACS

Large Eddy Simulation (LES) has already proved its ability to predict highly unsteady reacting flows in several academic studies and is seen to be applied to industry on more and more realistic and complex configurations. The scope of the present work is to demonstrate the maturity of LES when applied to several kinds of studies encountered in gas turbine design. First a feasability study is carried out on a helicopter combustion chamber, taking into account geometrical complexities, and highlights the great potential of LES to predict the right exit temperature distribution. Many issues remain unresolved in terms of models validity. Within this framework, sensitivity to mesh resolution then to chemical scheme on complex geometries is raised. The LES tool is then applied to an extinction sequence on the same helicopter combustor and mechanisms responsible for flame destabilisation are pointed out. Finally the analysis of a complete helicopter combustor, including all the entities, evaluates the thermo-acoustic stability of this highly complex configuration and the implication of a geometrical modification of the swirler.