Flame stabilization analysis of a premixed reacting jet in vitiated crossflow

The flame stabilization behavior of a premixed ethylene-air jet injected normal to a hot vitiated crossflow was examined using simultaneous OH planar laser induced fluorescence (PLIF) CH₂O PLIF and particle image velocimetry. The flame structure was divided into a windward and leeward flame branches. The unsteady windward flame displayed both attached and lifted flame behavior while the leeward flame branch remained consistently attached at the jet exit. Small scale vortices caused local wrinkling of the flame front. The windward flame wrapped around the large-scale vortices that formed along the jet shear layer. The leeward flame edge aligned with regions of high principal extensive strain-rate and high dilatation while the windward flame edge was located in regions where principal extensive and principal compressive strain rate magnitudes were high and dilatation was low. These suggest that auto-ignition is the dominant flame stabilization mechanism for the unsteady windward flame and premixed flame propagation is the more dominant stabilization mechanism for the leeward flame branch.