Experimental Investigation of Premixed Swirling Jet Flames : Combustion Characteristics

The flames in swirling jets are very stable when the swirl strength is adequate. Experiments were made of premixed swirling jet flames and the combustion characteristics were obtained in relation to swirl strength. Furthermore the stabilization mechanism of the flames was also explained qualitatively, using the experimental results of air jets. With an increase in swirl strength, a recirculation region develops and a flame rising near the nozzle exit forms a stable inverted cone surrounding this region. However, if the swirl is too strong, the excessive development of the region will result in so-called "high speed flash-back".