Chemiluminescence Emission of C₂, CH and OH Radicals from Opposed Jet Burner Flames

Abstract

Chemiluminescence emission from opposed jet burner flames was measured by a CCD (Charge Coupled Device) camera with an image intensifier. Radial profiles of the emission intensity were obtaine by the Abel transform of results of the side-on observation. The profiles of emission intensity of these radicals are similar and each peak is located at the center of the flame zone. The emission of C₂ and CH radicals produced in the early stage of the combustion reaction was observed on the burned gas side of the flame zone where the mean temperature is significantly high, suggesting that unburned mixture exists even on the burned gas side of the flame zone. From the emission profiles of OH radical which can be used as a measure of the reaction zone, it can be seen that the outer diameter of the flame zone increases with the mixture supply velocity, while the inner diameter remains constant. It was found that the profiles of OH emission intensity and NO concentration are similar. This fact suggests that NO originating from prompt NO is predominant in the distributed reaction zone.