DNS simulations of lean premixed flame kernels with flamelet generated manifolds: An overview

In this paper recent developments in the application of the method of flamelet generated manifolds (FGM) to simulations of turbulent premixed combustion are considered. Initially the method was developed for kinetic reduction for simulations of laminar combustion using stationary solvers. Recently the method was extended to direct numerical simulations of turbulent combustion. A lean premixed flame kernel was taken for a number of studies, investigating the application of the FGM technique. To that end the laminar mass burning rate was assessed in the context of the influence of stretch. Also a theoretical stretch model was involved in this test. It was found that the theoretical stretch was reproduced even up to the thin reaction zones regime. Validation also includes backsubstitution of stretched flamelets from the DNS into a detailed chemistry code. In two-dimensional cases a direct validation is performed with detailed chemistry for both unity Lewis numbers and physical Lewis numbers. Finally a flamelet theory of stretch effects in subgrid scales is evaluated from the DNS