Abstract: Apparatus and method for a combustion turbine engine are provided. A pre-mixing passage (24) has an upstream inlet arranged to receive a flow of air to be mixed with fuel. A fuel-injecting lance (12) is disposed in the pre-mixing passage. At least a first fuel ejection orifice (40) is disposed at a first axial location of the fuel-injecting lance. At least a second ejection orifice (42) is disposed at a second axial location of the fuel-injecting lance. A spacing between the first and second axial locations is arranged to effect oscillatory interference patterns in pockets comprising mixtures of air and fuel that flow towards a downstream outlet of the pre-mixing passage. The oscillatory interference patterns may be effective to promote homogeneity in the mixtures of air and fuel and dampen thermoacoustic oscillations in a flame (46) formed upon ignition of the mixtures of air and fuel.

Abstract: A gas turbine engine (202) including a secondary fuel stage (218) which also functions as a dual frequency resonator. The engine includes a combustor (210) and a casing (205) enclosing the combustor to define a volume (214). The secondary fuel stage includes a nozzle (217) sized to be effective as a transverse resonator at a high frequency. The nozzle and the volume (214) of the casing are sized to be effective as a longitudinal resonator at an intermediate frequency.