Stability Characteristics and NOx Emissions of Low Swirl Flames

Low swirl combustion is an innovative method for stabilizing lean premixed flames. Understanding the stability characteristics and NOx emissions of low swirl flames as well as influence of interaction of several low swirl flames on stability characteristic and NOx emissions are necessary to make low swirl burners applicable to various combustion chambers. The primary objectives of this study are to assess flame stability characteristics and NOx emissions of vane swirl burners. Since in an annular combustor several burners are mounted next to each other, the influence of flames interactions on the stability and NOx emissions of low swirl flames are examined. The data show that the stability of low swirl flames is highly dependent on the fuel-air mixture velocity at the burner exit, the mixture equivalence ratio, and the fuel-air feeding startegy to achieve the desired flame. NOx emissions of a low swirl flame are insensitive to the the fuel-air mixture velocity at the burner exit at a given equivalence ratio, but they are directly proportional to the equivalence ratio. Individual burner stablility is maintained when they are arranged in any annular formation. Although flames interactions have no influence on the overall flame stability characteristics but they increase NOx emissions.