Progress in large-eddy simulation of premixed and partially-premixed turbulent combustion

In many practical devices such as gas turbines and internal combustion engines, liquid fuel is injected as a spray and mixed with oxidizer as it vaporizes, so that combustion takes place in a partially-premixed regime. While partially-premixed flame propagation has been the subject of extensive experimental investigations (Su 2000; Muniz & Mungal 1997), its numerical simulation remains a challenging task. The mechanisms by which turbulence, chemical reactions, and heat release interact are still under investigation. Results by Veynante (1994) suggest the importance of premixed flame propagation in the process of flame stabilization. While DNS of turbulent premixed flames using realistic chemistry is still restricted to very simple geometries, classical RANS modeling of reacting flows is often considered to lack precision, especially when highly-unsteady problems are considered. Different methods have been suggested to model turbulent premixed combustion in LES (Colin 2000; Kim & Menon 2000; Duchamp de Lageneste & Pitsch 2000). An ap-proach based on a mixed level-set/diffusion-flamelet library applicable to premixed and partially-premixed combustion has been derived by Peters (1999) for RANS and validate