The present study is devoted to verify current capabilities of Large Eddy Simulation (LES) methodology in the modeling of lean premixed flames in the typical turbulent combustion regime of Dry Low gas turbine combustors. A relatively simple reactive test case, presenting all main aspects of turbulent combustion interaction and flame stabilization of gas turbine lean premixed combustors, was chosen as an affordable test to evaluate the feasibility of the technique also in more complex test cases. A comparison between LES and RANS modeling approach is performed in order to discuss modeling requirements, possible gains, and computational overloads associated with the former. Such comparison comprehends a sensitivity study to mesh refinement and combustion model characteristic constants, computational costs, and robustness of the approach. In order to expand the overview on different methods simulations were performed with both commercial and open-source codes switching from quasi-2D to fully 3D computations. 1. Introduction The emission reduction, especially of , has been the major driver for gas turbine development in the last decades. One of the most promising gas turbine combustion technologies to respect the strict legislative limits on pollutant emissions is the adoption of lean premixed flame. In the fields of combustion science and engineering, CFD calculations are now truly competitive with experiments and theory, as a research tool to produce detailed and multiscale information about combustion processes and play a crucial role in the design of environment-friendly devices. In particular, gas turbine combustion modeling, involving the interaction of many complex physical processes such as turbulent mixing and chemical reactions, comprises a wide range of computational and modeling challenges [1]. In this context LES is one of the most promising techniques as it allows a detailed resolution of the flow field and turbulent mixing phenomena. An axisymmetric bluffbody stabilized flame, reproducing typical lean premixed gas turbine combustor’s conditions, has been numerically studied, under adiabatic conditions, with the commercial code ANSYS Fluent vers.14.0, using LES coupled with the progress variable approach closed with Zimont Turbulent Flame Speed Closure (TFC) [2]. Numerical settings, mesh and time step sensitivity analysis are at first performed on a quasi-2D test case, representing a 5-degree slice of the complete geometry. Successively the fully 3D geometry has been simulated varying the combustion model constant controlling the source term
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