Study on a Change in the Behavior of Flame on Bluff-Body under the Transitional Regime by Swirled Air Flow

Abstract

The experimental study to investigate the effect of the swirling annular airflow by swirler with guided vanes for flame behavior under the transitional regime on a double concentric bluff-body burner was conducted. Propane gas was employed as the fuel gas and the swirler of the five types was prepared. The result shows that the swirling component of airflow makes a grate contribution to improve the flame stability and suggests that the geometrical swirl number larger than 0.6 and airflow velocity which exceeds a certain value are need to improve the stability. However, the result of the visualization of the flames reveals that the spread airflow by centrifugal force, which is prevented from mixing with fuel, accompanies stabilized flame. The result gives a surmise that it is difficult for the present burner to combine the flame stability and the perfect combustion.