ON-ENGINE EVALUATION OF EMISSIONS CHARACTERISTICS OF A VARIABLE GEOMETRY LEAN-PREMIXED COMBUSTOR

The design and on-engine testing of a lean-premixed low-NOx combustor for a simple-cycle, single-shaft, 250-kW gas turbine engine of a press ure ratio of eight are described. A variable-geometry system composed of butterfly air valves was used to control the combustor air split be tween combustion and dilution. Fuel was staged to a direct-injection p ilot burner, and a lean-premixed main burner was fitted to the combust or liner. The NOx emissions with natural gas fueling were found to be less than 20 ppm (at 15 percent O-2) at and near full-load conditions with combustion efficiencies greater than 99.8 percent. Emissions data from early high-pressure rig tests of the combustor hardware are also presented.