Stability and Behaviors of Diffusion Flame with Co-flowing air

Abstract

The flame stability limits essentially define the fundamental operation of the combustion system. The critical conditions at the stability limits are highly dependent on flow configurations and some species of fuels. For various species of fuels (Methane and Hydrogen). the flame-base stability mechanism for flame holding has been studied. In this study, the transition behavior from the stable flame attached to nozzle rim to lifting and blow off is observed experimentally, when the oxygen concentration of the co-flowing air is different. The lifting and blow-off criteria are proposed for the diffusion flame. Experiments were conducted to investigate the flame structure for various nozzle diameters from 0.14 to 8.1mm. The results obtained are as follows. The color distinction of a flame became dimmer, as the oxygen concentration of co-flowing air is smaller. The behaviors and stability of the diffusion flame depend on the spout velocity and the oxygen concentration of co-flowing air.