Abstract
In this study, a new ceramic-opposed jet burner was designed to ensure the adiabaticity of the flame. In the opposed-jet-turbulent premixed flame, the concentrations of various stable species as well as the mean flame temperature distributions and structures have been investigated. In the present burner, turbulent premixed flame can persist far beyond the stretch rate at which the wrinkled laminar flame is usually extinguished. The results show that the flame structure consists of the stretched stringy vortices involving variou sreacting species(e.g., C3H8, hydrocarbons, O2)which are referred to as the distributed reaction zones, and that the flames are divided into two categories:(1)transition flame from a wrinkled laminar flame to a distributed reaction zone, and(2)a fully developed distributed reaction zone. The structure of the distributed reaction zone depends mainly on the mixture jet velocity and is independent of the equivalence ratios. The stretched stringy vortice of the distributed reaction zone eradicates the nonuniformity of temperature and concentration fields. The hydrocarbon species as well as fuel are completely consumed in the distributed reaction zone, and almost complete combustion is achieved.
