Enhanced Stabilization of Multiple Premixed Flames with a Compressive Vortex Pair on a Stratified Burner

Abstract

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 (ϕ = 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) (1280×1024 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.

Keywords:

• Compressive vortex pair
• Premixed flame
• Stabilization
• Stratified burner

Additional information

Funding

The authors gratefully acknowledge the National Science Council of Taiwan, the Republic of China (Contract NSC 98-2623-E- 002-010-ET) for supporting this work.