Large eddy simulation of a turbulent swirling jet-A1 spray flame incorporating chemical non-equilibrium effects through the flamelet model

A large eddy simulation (LES) of a turbulent swirl stabilized jet-A1 flame is presented. The scope of the study is to incorporate a reduced chemistry model, as well as, coupling the turbulent flow characteristics to the chemical reactions and at the same time model the local chemical non-equilibrium due to the turbulent strain. Standard Eulerian and Lagrangian approaches are used to describe both gas and liquid phases, respectively. A joint presumed probability density function (PDF) is used to model turbulent-chemistry interactions in swirling jet-A1 spray flames. A one-component fuel, n-decane, is used as a surrogate for jet-A1. The combustion chemistry of the one component is represented through a reduced chemical kinetic mechanism (CKM) which comprises 139 species and 1 045 reactions, derived from the detailed jet fuel surrogate model, JetSurf 2.0. Numerical results of the gas velocity, the gas temperature and the species mole fractions are compared with a set of published experimental data of a steady flame. In addition to the overall reasonable agreement obtained with the experimental data, it is observed that, by combining a sufficiently realistic chemistry model with LES to simulate a jet-A1 spray flame, the prediction of major species is significantly improved while pollutants such as carbon monoxide (CO) and other species involved in slow reactions, are under predicted for reasons discussed in the paper.