Combustion Air Jet Influence on Primary Zone Characteristics for Gas-Turbine Combustors

Results are presented of emissions and lean blowout measurements in a generic combustor primary zone of an aircraft gas-turbine engine for the effects of opposed, circular combustion air jets of a range of sizes, positioned half a dome height downstream from the dome. The primary zone was operated at simulated engine high-power conditions and representative dome and liner pressure drops. Most of the NO x is generated in the jets. Although an optimum jet size is identified, the lowest overall emissions resulted from a no-combustion air-jet configuration; air jets are necessary, however, to confer lean blowout stability and short flame length.