A large-scale structural mixing model applied to blowout of turbulent non-premixed jet flames in a cross air-flow

Abstract

This paper presents an application of a large-scale structural mixing model(17) to the blowout of turbulent reacting jets discharging perpendicularly into an unconfined cross-flow. Experimental observations aim at identifying the existence of a large-scale vortical structure exerting an important effect on flame stabilisation. In an analysis of a common stability curve, a plausible explanation can be made that the phenomenon of blowout is related only to the mixing time scale of the two flows. The most notable observation is that the blowout distance is traced at fixed positions at all times, according to the velocity ratio R. Measurements of the lower blowout limits in the liftable flame agree qualitatively with the blowout parameter epsilon proposed by Broadwell et al(17). Good agreement between the results calculated by a modified blowout parameter epsilon' and experimental results confirms the important effect of a large-scale structure in specifying the stabilisation feature of blowouts.