Lagrangian Investigation of Auto-ignition in a Hydrogen Jet Flame in a Vitiated Co-flow: Animations of Particle Trajectories in Composition Space from PDF Model Calculations

PDF model calculations have been performed of the Cabra lifted hydrogen flame in a vitiated co-flow. Particle trajectories are extracted from the Lagrangian particle method used to solve the modeled PDF equation. The particle trajectories in the mixture fraction-temperature plane reveal (at successive downstream locations): essentially inert mixing between the cold fuel jet and the hot co-flow; the auto-ignition of very lean particles; and, subsequent mixing and reaction, leading to near-equilibrium compositions. The purpose of this paper is to present animations of the particle trajectories obtained using different turbulent mixing models.