A gas-air premixing burner for gas turbines includes an air swirler and an annular burner tube surrounding a bluff centerbody. The bluff body serves to stabilize the flame by defining a recirculating vortex. Cooling air is directed to impinge against the bluff face of the centerbody and the spent impingement cooling air flows in a reverse direction towards the air swirler within the centerbody and is discharged through holes at the outer diameter of the centerbody, where it mixes with the fuel/air mixture prior to reaching the flame zone.
A secondary combustion system for a stage one turbine nozzle. The secondary combustion system may include a supply tube extending into the stage one nozzle, a number of injectors extending from the supply tube to an outer surface of the stage one nozzle, and an air gap surrounding each of the number of injectors.
