Laser Diagnostics Of The Flow In Industrial Burners

Laser based visualization of the flow and laser-Doppler measurements of mean and turbulent velocity characteristics are reported in the developing region of the reacting and non-reacting swirling flows of a model of an industrial oxy-fuel burner. The burner consists in a central axysimmetric swirling jet surrounded by sixteen circular jets, simulating the injection of oxygen in practical burners. The experiments have been carried out to investigate the three-dimensional characteristics of the near burner region, the flame structure and the process of flame stabilization and show the efficiency of laser-based diagnostics to study the aerodynamics of industrial burners. The results suggest that the flame may be represented by laminar flamelet concepts and that the flow becomes axisymmetric upstream of one central-jet diameter. The stabilization of the flame occurs in the vicinity of the quarl, away of the central, swirl-driven recirculation zone. The effect of swirl is, however, essential to improve turbulent mixing and to decrease the entrainment of ambient air into the quarl.