Effects of Location and Direction of Diluent Injection on Radiation and Pollutant Emissions of a Burning Spray

Abstract

Introduction of diluents into diffusion flames is an effective method of changing their combustion and pollutant emission characteristics. Since the dominant thermochemical processes vary from region to region of a burning spray, diluent injection at different locations of a flame can affect its overall characteristics differently. This study examines the effects of location and orientation of N2 injection into an air-atomized kerosene spray flame. Flame length, radiant emission, temperature profiles, flame opacity, and concentration profiles of NO, CO, and soot are measured. The overall emission indexes of NO, CO, and soot are calculated. Results show that the diluent injection in the axial downstream direction is superior to the radial injection from the point of reducing heat loss to the combustor walls. The location of injection affects flame characteristics substantially. Injection of diluent into midflame region produces largest reductions in radiation, flame length, and emissions of soot and CO. Nitric oxide emission does not depend significantly on the location of injection.