Chapter 19 - Introducing chemical kinetics into Large Eddy Simulation of turbulent reacting flows

Abstract

Abstract Today code performances and sophisticated models for turbulent combustion allow to accurately predict flames in complex geometries. The request for more environmentally-friendly combustion systems calls now for the accurate description of chemistry, which drives pollutant emissions, but also the impact of alternative fuels or ignition capabilities. To do so, one promising approach is the so-called ARC-LES, where the chemistry is described with analytically reduced chemistry (ARC) and the turbulent combustion is modeled in the large eddy simulation (LES) framework. ARC-LES realizes an excellent compromise between accuracy and computing cost, as ARC retains the most important chemical paths and LES directly resolves the most important turbulent scales. In this chapter, the ARC concept is described in detail. After explaining the method of derivation of ARC schemes, several examples of application to turbulent flames show that ARC-LES well captures the turbulence-chemistry interaction in complex flows, and leads to very good predictions of the flame structure and emissions.