Effects of Stratification and Preheat on Turbulent Flame Characteristics and Stabilization

A Study of Recirculating Flow Fields Downstream of a Diverse Range of Axisymmetric Bluff Body Geometries Suitable for Flame Stabilization

“…This suggests that smaller bodies, and particularly disk shaped ones, could accommodate flame stabilization of fuel-oxidizer mixtures that are less resilient to aerodynamic stretch and have lower extinction stretch values, i.e., a lean heptane-air mixture is more vulnerable to extinction due to aerodynamic stretches than a propane-air mixture, therefore a disk shaped body with a small blockage ratio seems more promising for heptane-air mixture stabilization than a larger blockage ratio cone shaped body, with the same thickness. Nevertheless, such observations can only be of a tentative nature regarding the behavior of a reacting front: flame extinction is a time dependent phenomenon and depends not only on the peak stretch exerted on the flame front but also on the probability for these stretch values to occur and on the relevant turbulent reacting front regime of the specific flame [40].…”

“…These respective investigations concentrated on the study of the scalar mixing properties for different baffle shapes [38] and on the reacting properties with or without the impact of swirl [11,24,37,39], under stratified or fully premixed inlet mixture conditions. Additionally, investigations regarding the effect of both stratification and preheat on the reacting front have been presented in [12,30,40], while in [41] the authors have discussed the influence of acoustic modulation of the incoming velocity and equivalence ratio gradient on the combustion zone.…”