JET SHEAR-LAYER TURBULENT-DIFFUSION FLAMES FOR ULTRALOW NOX EMISSIONS

Direct fueling of each shear layer generated by an array of holes in a grid plate was shown to have ultralow NO(x) emissions combined with a good flame stability, compared with a premixed system. Two methods of fuel injection were investigated that had opposite NO(x)/stability characteristics. Four shear layers in a 76-mm combustor were used at gas turbine primary zone operating conditions with 60 percent simulated primary zone air at one bar pressure. The fuels used were propane and natural gas and a minimum NO(x) emission of 2.5 ppm at 15 percent oxygen, compatible with a 0.1 percent inefficiency, was demonstrated for natural gas with a reasonable stability margin. These designs have the potential for a dry NO(x) solution to any current or proposed gas turbine NO(x) regulation for natural gas.