A Numerical Analysis of a Conical Swirl-Stabilized Spray Burner

Abstract

Numerical calculations of the droplet dispersion in a conical spray burner are presented. A commercial CFD code, FLUENT, is used to execute the numerical calculations. The burner has the shape of a cone, which is offset in four places. These four gaps allow for secondary air injection into the burner region, and provide a high level of swirl. The fuel spray, together with coaxial primary air, in both co-swirl (primary air swirling in the same direction as the secondary air), and counter-swirl configuration are introduced at the base of the burner. Results indicate that the counter-swirl configuration leads to uneven fuel distribution and local pockets of high stoichiometry. Increasing the swirl ratio between the primary and secondary stream enhances the central recirculation region that is likely to promote flame stability, but adversely affects the mixing and fuel distribution. Increasing air to fuel flow momentum ratio leads to low droplet dispersion but higher turbulent level.