A Large-Eddy Simulation Technique for the Prediction of Flow, Mixing and Combustion in Gas Turbine Combustors
The development of new combustion concepts in gas turbines and aero engines calls for accurate simulation tools to predict the turbulent flow, mixing and combustion in such devices. High levels of swirl often lead to precessing vortex core type instabilities and pose a challenge to the turbulence model while for non-premixed combustion flame lift-off and the consequent partial premixing require adequate modelling. This work presents a simulation approach based on the large-eddy simulation technique. A numerical technique is developed for solving the governing equations for low-Mach number in complex geometries. The method is applied to a number of test cases, among them a generic combustor rig. A comparison of the steady flamelet model with a reduced mechanism based on flamelet generated manifolds shows that for an accurate description of flow field and flame characteristics the steady flamelet model is not sufficient while the inclusion of kinetic effects via the progress variable contained in the reduced mechanism leads to a good overall prediction.