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The method of large eddy simulation (LES) has a high potential to accurately predict complex turbulent flows. Gas turbine combustion systems feature a number of phenomena interacting with each other such as swirl with recirculation, complex turbulent mixing and combustion of premixed, non-premixed as well as partially premixed nature. We therefore tend to approach the simulation of real gas turbine combustors step by step. The aim of this paper is to document some of the progress made at EKT in assessing the capability of LES in flows separately exhibiting distinct features of gas turbine combustors. Some results from two configurations are presented and discussed: a non-confined isothermal swirl flow with precessing vortex core and a non-premixed bluff-body flame.

In order to evaluate the direct and indirect contributions to the total combustion noise emission, a combustion chamber consisting of a swirl burner and an exit nozzle of Laval-shape, representing a gas turbine combustor, is investigated by means of experiments and large eddy simulation. Focused on the isothermal flow case first and encouraged by a good overall agreement between the LES and the experimental data for the flow field, a first characterisation of the flow with respect to noise sources is performed. To analyse acoustic properties of the flow, time and length scales are evaluated inside the combustor. Furthermore, the evidence for the existence of a precessing vortex core (PVC), typical for configurations with swirl, is revealed. Finally, the effect of the PVC on the flow inside the Laval nozzle is discussed.