A pilot burner for a combustor includes an inner conduit configured to deliver a fuel, and an outer conduit concentric with the inner conduit and configured to deliver air. An inner wall defines an inner plenum, and a partition wall is radially outward of the inner wall and defines an intermediate plenum with at least a portion of the inner wall. Exit passages fluidly couple the inner plenum to the intermediate plenum. An outer wall defines an outer plenum with at least a portion of the partition wall. A crossover section includes passages fluidly coupling the inner conduit to the outer plenum, and passages fluidly coupling the outer conduit to the inner plenum. An end plate includes openings to direct fuel, air for combustion, and air for cooling from the respective plenums.

An embodiment of a torch ignitor system for combustor of a gas turbine engine includes a torch ignitor, the torch ignitor having a combustion chamber oriented about an axis, the combustion chamber having axially upstream and downstream ends defining a flow direction through the combustion chamber, along the axis. The torch ignitor system also includes a cap defining the axially upstream end of the combustion chamber and oriented about the axis, wherein the cap is configured to receive a fuel injector and at least one glow plug, a tip at a downstream end of the combustion chamber, and a passage for pressurized oxygen containing gas passing through the cap from an exterior of the combustion chamber and in fluid communication with the combustion chamber. An embodiment of a method for starting a gas turbine engine is also disclosed.

Fuel nozzle assemblies are provided. For example, a fuel nozzle assembly for a combustor system comprises a fuel nozzle having a pilot swirler and an outlet defined in an outlet end, as well as a main mixer attached to the outlet end and extending about the outlet. A total combustor airflow through the combustor system comprises a pilot swirler airflow that is greater than about 14% and a main mixer airflow that is less than about 50% of the total combustor airflow. In further embodiments, the fuel nozzle also comprises main and pilot fuel injectors that each are configured to receive a portion of a fuel flow to the fuel nozzle. The fuel nozzle provides less than about 80% of the fuel flow to the main fuel injector at a high power operating condition of a gas turbine engine in which the fuel nozzle assembly is installed.

A pilot burner for a combustor includes an inner conduit configured to deliver a fuel, and an outer conduit concentric with the inner conduit and configured to deliver air. An inner wall defines an inner plenum, and a partition wall is radially outward of the inner wall and defines an intermediate plenum with at least a portion of the inner wall. Exit passages fluidly couple the inner plenum to the intermediate plenum. An outer wall defines an outer plenum with at least a portion of the partition wall. A crossover section includes passages fluidly coupling the inner conduit to the outer plenum, and passages fluidly coupling the outer conduit to the inner plenum. An end plate includes openings to direct fuel, air for combustion, and air for cooling from the respective plenums.

A premixer array for a gas turbine engine includes a plurality of swirled premixer tubes and a plurality of non-swirled premixer tubes. The premixer array further includes a pilot tube for providing a pilot product. The plurality of swirled premixer tubes may guide and spread out the pilot product in a radial direction, in a circumferential direction, or both in a radial direction and a circumferential direction. The plurality of swirled premixer tubes may include clockwise swirled and counterclockwise swirled premixers. Also, included is a method of controlling the flow of pilot products.

Provided is a gas turbine combustor that can achieve improvement of the combustion stability. A gas turbine combustor includes a pilot burner of the diffusion combustion type, a pilot flow control valve that regulates a flow rate of fuel to be supplied to the pilot burner, a main burner of the premix combustion type arranged on an outer circumference side of the pilot burner, main flow control valves that regulate flow rates of fuel to be individually supplied to burner sectors into which the main burner is sectioned in a circumferential direction, and a controller configured to control the pilot flow control valve and the main flow control valves. The controller controls the main flow control valves such that, when fuel is to be supplied to all the burner sectors, a difference in fuel flow rate occurs between at least one burner sector and the other burner sectors among the burner sectors.

Combustor systems are provided. For example, a combustor system comprises a combustor having forward and aft ends and including annular inner and outer liners that each extend generally along an axial direction and define a combustion chamber therebetween. The combustor system also comprises a fuel nozzle having an outlet defined in an outlet end of the fuel nozzle and including a pilot swirler. The outlet is positioned at the forward end of the combustor to direct a fuel-air mixture into the combustion chamber. The combustor system further comprises a main mixer attached to the outlet end of the fuel nozzle and extending about the outlet. A total combustor airflow through the combustor comprises a pilot swirler airflow that is greater than about 14% of the total combustor airflow and a main mixer airflow that is less than about 50% of the total combustor airflow.

A premix pilot nozzle is disclosed herein. The premix pilot nozzle includes a nozzle body. The nozzle body includes a forward wall, an aft wall, an outer band that extends between the forward wall and the aft wall and a tip portion that extends axially downstream from the aft wall. The nozzle body further defines a fuel inlet plenum that extends coaxially within the nozzle body, a fuel distribution plenum that is defined within the nozzle body radially outwardly from and in fluid communication with the fuel inlet plenum, a plurality of premix passages that extend helically around the fuel inlet plenum within the fuel distribution plenum and a plurality of air passages annularly arranged around the plurality of premix passages. One or more premix passages of the plurality of premix passages are in fluid communication with the fuel distribution plenum.

A premix pilot nozzle and fuel nozzle assembly are disclosed herein. The premix pilot nozzle includes a nozzle body having a forward wall axially spaced from an aft wall and an outer band that extends axially between the forward wall and the aft wall. An air tube extends coaxially within the nozzle body and defines a cooling air plenum within the nozzle body. A fuel tube extends coaxially within the nozzle body and circumferentially surrounds the air tube so as to define a fuel inlet plenum therebetween. A fuel distribution plenum is defined within the nozzle body and is in fluid communication with the fuel inlet plenum. The nozzle body further includes a plurality of premix tubes. Each premix tube extends helically around the fuel tube within the fuel distribution plenum. One or more of the premix tubes is in fluid communication with the fuel distribution plenum.

A premix pilot nozzle includes a tip portion having a downstream surface that extends between a downstream end of an inner wall of the tip portion and a downstream end of an outer wall of the tip portion. The downstream end of the inner wall terminates axially upstream from the downstream end of the outer wall. At least a portion of the downstream surface is curvilinear. The tip portion further comprises a plurality of axially extending premix tubes annularly arranged about the tip portion. Each premix tube defines a premix flow passage through the tip portion. Each premix tube also includes an outlet that is axially offset from the downstream surface.