ENHANCED STABILIZATION OF MULTIPLE PREMIXED FLAMES WITH A COMPRESSIVE VORTEX PAIR ON A STRATIFIED BURNER

摘要

An innovative burner design for premixed combustion demonstrates combustion phenomena and stability relevant to high flame/flow interaction. The burner generates a compressive vortex-pair structure to expand the region of stable flame operation (phi= 0.5 under an open-flame condition). The stabilized effects between flames and flow structure were explored, particularly the preheating and mixing characteristics. The flow visualization and velocity distribution measured with particle-image velocimetry (PIV) (1280x1024 pixels at 1000 Hz) show that the compressive vortex-pair structure is induced by inner-injection and middle-injection wake vortices in combination. The evolution of the transient flow and statistical analysis show that the compressive vortex-pair structure effectively induces greater turbulent intensity to enhance the flame intensity, and thus achieves a salient performance of stabilization. This work provides a valuable concept for the application of a stratified burner for bio-syngas combustion because of its flexible control and capability to stabilize a flame.