B. Wegner

Large eddy simulation of combustion processes under gas turbine conditions

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.

Study of Flow and Mixing in a Generic GT Combustor using LES

Due to careful and deliberate trade-offs between often conflicting design requirements (low emission, high operating pressure and temperatures etc.), development and improvement of gas turbines nowadays relies heavily on advanced simulation methods. While the basic capability of LES has been amply demonstrated on a number of relatively simple academic configurations, there is still a lack of works applying LES to practical systems also performing detailed quantitative comparisons based on experimental data. This is mostly due to the lack of suitable reference data. In this paper, we present results of the isothermal LES of a generic gas turbine combustor rig studied in house by means of advanced laser measurement techniques. The results of these detailed measurements are used to thoroughly validate the LES results. Beyond a pure validation, the LES is used to analyse the influence of the precessing vortex core present in the studied configuration on the mixing of fuel and oxidizer and possible implications for reacting conditions are discussed.