Elliptic Coflow Effects on a Circular Gas Jet Flame

Abstract

The effects of elliptic coe ow on the structure of a propane jet e ame are presented. The interaction of a fuel jet and a coe ow in the shear layer enhances the mixing behavior of the e owe eld and affects the combustion characteristics of diffusion e ames. Nonaxisymmetric exit jet geometries are characterized by better mixing and increased e uid entrainment into the jet core, which is desirable for low pollution from a diffusion-controlled combustion environment. In the present study the interaction of an elliptic coe ow with a propane jet e ame issued from a circular tube burner has been studied. Pollutant emission, e ame radiation, e ame structure, and soot concentration have been measured. The fuel jet exit Reynolds number is 2.7 ££ 10 3 , and the exit Reynolds number for the coe ow is 4.01 ££ 103 and 8.02 ££ 103 based on the minor and major axis, respectively. The results are compared with the measurements from the experiments on the same burner in a circular coe ow. The pollution characteristics and the e ame structure of the e ame in the elliptic coe ow are signie cantly different from those in the circular coe ow. The nitric-oxide emission is higher, and the carbon-monoxide emission is lower in the elliptic coe ow than in the circular coe ow. The elliptic coe ow e ame produces less soot than the circular coe ow e ame.