Spatial Structure of a Reacting Turbulent Swirling Jet Flow with Combustion of a Propane–Air Mixture

Abstract

Results of an experimental study of the spatial structure of a reacting flow during combustion of a propane–air mixture in a turbulent swirling jet escaping into atmospheric air are presented. The fuel-to-air equivalence ratio is φ = 0.7, and the Reynolds number of the jet is Re = 5 · 10³. The time-averaged spatial distributions of velocity, local density, and concentrations of the main species of the gas mixture are measured in low-swirl and high-swirl flows. In both cases, the flame front is stabilized in the internal mixing layer formed by the axial region of jet retardation, where hot combustion products are concentrated. In a high-swirl flow, the temperature distributions in the cross section y/d = 0.5 show that the region with the maximum temperature of the gas is located at the periphery of the central recirculation zone. Moreover, in the case of a high-swirl flow, there exists a recirculation zone at the axis, and the CO₂ concentration is twice higher than in a low-swirl jet. The opposite situation is observed for O₂.