LES/probability density function approach for the simulation of an ethanol spray flame

A consistent probability density function (PDF) based combustion modeling approach for large eddy simulation of turbulent spray combustion is formulated. A Lagrangian Monte-Carlo approach for solving the PDF transport equation in the context of low-Mach number LES formulations is developed. The LES/PDF approach is used to simulate an experimental pilot-stabilized ethanol spray flame. In this particular flame, droplet evaporation occurs away from the flame front, leading to separation of the two processes. A high-temperature pre-flame zone with a stratified mixture is found to exist throughout the length of the flame. The high flow rate of the droplet-laden air prevents the flame front from propagating through this evaporated, but well-mixed fuel/air mixture. Comparison with experiments displayed large discrepancies concerning the droplet inflow conditions. In particular, the inflow turbulence is significantly modified by droplet-turbulence interactions in the injection pipe. (C) 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved.