Patent ID: 8522556

Claim:
An air-staged diffusion nozzle disposed in a combustor of a gas turbine including a gas-fuel source and a compressed air source wherein the gas-fuel nozzle discharges to a burner tube space of the combustor, the air-staged diffusion nozzle comprising: providing an air-staged diffusion nozzle comprising a nozzle body including a gas-fuel cavity bounded by an outer peripheral wall disposed along a longitudinal axis of the nozzle; an end closure wall, a cooling air chamber disposed within the gas-fuel cavity; an outer swirler supplied by gas-fuel from the gas-fuel cavity and compressed air from an external space surrounding the nozzle body; and a forward projection of the cooling air chamber, extending through the peripheral wall of the within and projecting through an end closure nozzle body disposed along a longitudinal axis including the gas-fuel cavity, bounded distally by the end closure wall, bounded proximally by a connection to the gas-fuel source, and bounded peripherally by an annular wall; the outer swirler with swirl vanes extending from a tip end of the annular wall forming a swirled axial passage to a downstream burner tube space; a space external to the annular wall of the gas-fuel cavity including a compressed air source in fluid communication with the swirled axial passage of the outer swirler, and a plurality of passages through the annular wall from the gas-fuel cavity into the swirled axial annular passage of the outer swirler, wherein the outer swirler delivers a swirling mixture of a gas-fuel and the compressed air to the downstream burner tube space of the combustor; the cooling air chamber enclosed within the gas-fuel cavity and comprising the outer peripheral wall, wherein the outer peripheral wall disposed in proximity to the distal end of the gas-fuel cavity extends axially through the end closure wall to the burner tube space of the combustor; a plurality of passages through the annular wall of the gas-fuel cavity from the external compressed air space coupled in fluid communication with the cooling air chamber; and a plurality of passages fluidly communicating compressed air through the distal end of the peripheral wall of the cooling air chamber to the burner tube space of the combustor, wherein the plurality of passages fluidly communicating compressed air between the cooling air chamber and the burner tube space of the combustor comprise: tip holes on the tip end of the projection of the cooling air chamber providing a swirled discharge of compressed air in a same rotational direction as provided by the outer swirler.