A swirler assembly includes a swirler having a primary swirler with a primary swirler venturi, a swirler ferrule plate connected upstream to the primary swirler, and a fuel nozzle disposed in the swirler ferrule plate. The swirler ferrule plate has an annular pressure drop cavity with oxidizer inlet orifices in fluid communication with the swirler, and at least one outlet orifice in fluid communication with the primary swirler venturi. A second flow of oxidizer to the swirler incurs a first pressure drop, a third flow of the oxidizer from the swirler to the annular pressure drop cavity incurs a second pressure drop, and a fourth flow of the oxidizer from the annular pressure drop cavity to the primary swirler venturi incurs a third pressure drop.

A combustor assembly for a gas turbine engine according to an example of the present disclosure includes, among other things, a combustion chamber, and a fuel injector assembly in communication with the combustion chamber that has a swirler body situated about a nozzle to define an injector passage that converges to a throat. The throat is defined at a distance from the combustion chamber. The nozzle includes a primary fuel injector and an array of secondary plain jet fuel injectors.

A method and structure for operating a combustion system of a gas turbine engine to mitigate low frequency combustion acoustics is generally provided. The method includes flowing an oxidizer through a fuel nozzle passage defining an inner wall and an outer wall, in which each of the inner wall and the outer wall are contoured from a first radius to a second radius smaller than the first radius; flowing the oxidizer at a higher axial velocity at the inner wall relative to the outer wall upstream of a fuel injection port; flowing a fuel through the fuel injection port to the fuel nozzle passage to mix with the flow of oxidizer to produce a fuel-oxidizer mixture; and igniting the fuel-oxidizer mixture downstream of the fuel injection port.

A method and structure for operating a combustion system of a gas turbine engine to mitigate low frequency combustion acoustics is generally provided. The method includes flowing an oxidizer through a fuel nozzle passage defining an inner wall and an outer wall, in which each of the inner wall and the outer wall are contoured from a first radius to a second radius smaller than the first radius; flowing the oxidizer at a higher axial velocity at the inner wall relative to the outer wall upstream of a fuel injection port; flowing a fuel through the fuel injection port to the fuel nozzle passage to mix with the flow of oxidizer to produce a fuel-oxidizer mixture; and igniting the fuel-oxidizer mixture downstream of the fuel injection port.

A premixer assembly for a combustor includes: at least one ring of premixers, each premixer having a central axis, an annular peripheral wall surrounding a centerbody, and at least one swirler disposed between the centerbody and the peripheral wall, wherein the peripheral wall defines an inlet area of the premixer; and a lip extending forward along the central axis from the peripheral wall, the lip extending at an oblique angle to the axis of symmetry.

A combustor assembly for a gas turbine engine according to an example of the present disclosure includes, among other things, a combustion chamber, and a fuel injector assembly in communication with the combustion chamber that has a swirler body situated about a nozzle to define an injector passage that converges to a throat. The throat is defined at a distance from the combustion chamber. The nozzle includes a primary fuel injector and an array of secondary plain jet fuel injectors.

An air and gas feeder device for gas boilers, comprising an air-gas conveyance body which comprises: a boiler coupling face configured to be coupled to a boiler at an intake duct of the boiler; an air intake port connected to an air discharge opening by means of an air passage, the air discharge opening leading out from the boiler coupling face; a gas intake port, configured to be fixed to a gas dispensing duct in fluid communication with a gas discharge opening, which leads out from the boiler coupling face; wherein the air discharge opening is coaxial to, and at least partially surrounded by, the gas discharge opening; the air passage accommodates a flow diverter configured to divert an air flow in output from the air discharge opening in the direction of the gas in output from the gas discharge opening and to impart a rotation to said air flow.

A premixer for a combustor includes: a centerbody having a hollow interior cavity; a swirler assembly radially outward of the centerbody; a peripheral wall disposed radially outward of the centerbody and the swirler assembly such that a mixing duct is defined between the peripheral wall and the centerbody, downstream from the swirler assembly; an annular splitter radially inward of the swirler assembly and radially outward of the centerbody such that a radial gap is defined between the splitter and an outer surface of the centerbody, wherein the splitter includes a trailing edge which extends axially aft of the swirler assembly; a fuel gallery disposed inside the interior cavity of the centerbody; and at least one fuel injector extending outward from the fuel gallery and passing through an injector port communicating with the outer surface of the splitter.

A premixer for a combustor includes: a centerbody having a hollow interior cavity; a swirler assembly radially outward of the centerbody; a peripheral wall disposed radially outward of the centerbody and the swirler assembly such that a mixing duct is defined between the peripheral wall and the centerbody, downstream from the swirler assembly; an annular splitter radially inward of the swirler assembly and radially outward of the centerbody such that a radial gap is defined between the splitter and an outer surface of the centerbody, wherein the splitter includes a trailing edge which extends axially aft of the swirler assembly; a fuel gallery disposed inside the interior cavity of the centerbody; and at least one fuel injector extending outward from the fuel gallery and passing through an injector port communicating with the outer surface of the splitter.

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.