An engine can utilize a combustor to combust fuel to drive the engine. A fuel nozzle assembly can supply fuel to the combustor for combustion or ignition of the fuel. The fuel nozzle assembly can include a swirler and a fuel nozzle to supply a mixture of fuel and air for combustion, which can supply a primary fuel supply and a secondary fuel supply. Increasing efficiency and reducing emission require the use of alternative fuels, which combust at higher temperatures or burn at faster burn speeds than traditional fuels, requiring improved fuel introduction without the occurrence of flame holding or flashback.

A swirler apparatus for a combustor, including: primary and secondary swirlers disposed axially adjacent to each other along a swirler centerline; the primary swirler including a plurality of primary swirl vanes arrayed around the swirler centerline, each primary swirl vane including opposed sides bounded between opposed forward and aft edges and opposed leading and trailing edges; wherein the forward edge is oriented at a first vane angle with respect to a radial direction; wherein the aft edge is oriented at a second vane angle with respect to the radial direction; wherein the second vane angle is different from the first vane angle; and the secondary swirler including a plurality of secondary swirl vanes arrayed around the swirler centerline.

The invention relates to a premixing method for premixing fuel with air prior to the combustion of a fuel/air mixture to allow burners to be operated at high output and with a good load variation range with stable and reliable operation and low NOx emissions. The method comprises: a) creating a rich fuel/air mixture with a fuel/air ratio above an ignitable fuel/air ratio, b) supplying air to the rich fuel/air mixture to obtain an ignitable fuel/air mixture, and c) swirling the ignitable fuel/air mixture obtained in step a) or b). The invention further relates to a premixing device for performing the method.

A fuel injection nozzle for a combustion turbine engine has thermal stress-relief vanes, which accommodate and relieve localized thermal stresses within its monolithic, three-dimensional nozzle structure, imparted by heat transfer during engine combustion. At least one first vane is coupled to opposing, spaced nozzle sleeves at both ends. At least one cantilever-like second vane is coupled to one of the opposing sleeves on one end, while the other free or floating end is spaced by a second vane gap from the other opposing sleeve. Some embodiments include a plurality of second vanes, which have locally varying orientation, and/or structure, and/or second vane gaps, for normalizing spatially and/or temporally thermal stresses within the nozzle structure. The monolithic structure is fabricated, in some nozzle embodiments, by additive manufacturing.

A combustion head for a burner is provided with an outer sleeve, which houses, on the inside, a first feeding device to feed a gaseous fuel into an oxidizing air flow fed along the outer sleeve by means of a pneumatic ventilation device, at least one swirl device, which is configured to cause a primary flow F.sub.1 of gaseous fuel and oxidizing air flowing out of the outer sleeve to make a helical movement, and at least one feeding channel with an annular shape, which is obtained between the outer sleeve and the swirl device in order to feed a secondary flow F.sub.2 of oxidizing air around the primary flow F.sub.1; a second feeding device being mounted on the outside of the outer sleeve and being connected to a gaseous fuel source.

An injection system includes a radial swirler defining an axis and including a plurality of radial swirl vanes configured to direct a radially inward flow of compressor discharge air entering swirler inlets between the radial swirl vanes in a swirling direction around the axis. The radial swirler includes an outlet oriented in an axial direction to direct swirling compressor discharge air in an axial direction. An injector ring is included radially outward from of the swirler inlets. The fuel injector ring is aligned with the axis and includes a plurality of injection orifices directed towards the swirler inlets for injecting fuel into the radial swirler.

Disclosed are a fuel nozzle assembly, and a fuel nozzle module and gas turbine having the same. The fuel nozzle assembly includes a fuel nozzle, a shroud spaced apart from the fuel nozzle and defining a flow path between an inner wall and the fuel nozzle, a rim formed around the shroud to guide air, and a turning guide spaced apart from the rim to distribute the air. The turning guide includes a turning separator spaced apart from the rim to extend in a circumferential direction of the rim, and inner separators extending in a radial direction of the rim to interconnect opposite circumferential ends of the turning separator and an outer surface of the fuel nozzle. The fuel nozzle assembly prevents air pockets, and ensures uniform supply of air, thereby preventing a local increase in combustion temperature inside the fuel nozzle and reducing generation of NOx.

A premixed low-nitrogen gas boiler is provided, which includes a reversed flow-swirl mixer being opposite mixing of natural gas and air. A flow deflector is arranged at a gas mixture outlet of the reversed flow-swirl mixer. An upper flow equalizing plate and a lower flow equalizing plate are arranged below the flow deflector, the upper flow equalizing plate is positioned above the lower flow equalizing plate, and a channel for enhancing mixing of gas mixture is formed between the upper flow equalizing plate and the lower flow equalizing plate. A comb-shaped water-cooled burner is arranged at the rear end of the lower flow equalizing plate, a combustion chamber is arranged at the rear end of the comb-shaped water-cooled burner, hearth tube bundles are arranged in a ladder-shaped convergent hearth, and the hearth tube bundles form an inner loop with a working medium water-steam mixture in a hearth water tank.

A combustor for a gas turbine, having a pre-combustion chamber having a peripheral wall around a center axis of the pre-combustion chamber, the peripheral wall has an inner panel and an outer panel and a passage provided between the inner and the outer panels, a swirler which is connected to the pre-combustion chamber for providing pre-combustion chamber with a flow of an oxidant gas, at least a pilot fuel injector, wherein the swirler is connected to the peripheral wall in such a way that a portion of the oxidant gas from the swirler is channeled to the passage, and the pilot fuel injector is connected to the passage for injecting a flow of pilot fuel into the passage.

A fuel swirler with anti-rotation features is provided. A swirler assembly may comprise a swirler, a guide plate, and a retaining ring. The swirler, the guide plate, and/or the retaining ring may comprise recessions configured to receive a retaining element. The retaining element may be configured to interface with the recessions to create an interference in the swirler assembly. The interference may at least partially resist rotation of the guide plate with respect to the swirler.