Using LES to Study Reacting Flows and Instabilities in Annular Combustion Chambers

Pierre Wolf (1) , Ramesh Balakrishnan (2) , Gabriel Staffelbach (1) , Laurent Y.M. Gicquel (1) , Thierry Poinsot (3)

1 CERFACS - Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique
2 ANL - Argonne National Laboratory [Lemont]
3 IMFT - Institut de mécanique des fluides de Toulouse

Great prominence is put on the design of aeronautical gas turbines due to increasingly stringent regulations and the need to tackle rising fuel prices. This drive towards innovation has resulted sometimes in new concepts being prone to combustion instabilities. In the particular field of annular combustion chambers, these instabilities often take the form of azimuthal modes. To predict these modes, one must compute the full combustion chamber, which remained out of reach until very recently and the development of massively parallel computers. Since one of the most limiting factors in performing Large Eddy Simulation (LES) of real combustors is estimating the adequate grid, the effects of mesh resolution are investigated by computing full annular LES of a realistic helicopter combustion chamber on three grids, respectively made of 38, 93 and 336 million elements. Results are compared in terms of mean and fluctuating fields. LES captures self-established azimuthal modes. The presence and structure of the modes is discussed. This study therefore highlights the potential of LES for studying combustion instabilities in annular gas turbine combustors.

Mots clés: Combustion instabilities; Large Eddy Simulation; Annular gas turbines; Mesh resolution

Domaines: Thermique [physics.class-ph]; Thermique [physics.class-ph]

Pierre Wolf, Ramesh Balakrishnan, Gabriel Staffelbach, Laurent Y.M. Gicquel, Thierry Poinsot. Using LES to Study Reacting Flows and Instabilities in Annular Combustion Chambers. Flow, Turbulence and Combustion, 2012, vol. 88, pp.191-206. ⟨10.1007/s10494-011-9367-7⟩. ⟨hal-00812024⟩