CN-117321340-B - Fuel injector and fuel nozzle for a gas turbine and gas turbine engine comprising such a nozzle

Abstract

The present disclosure provides a fuel injector (19) comprising a fuel feed chamber (21) and a central body (31) extending along a longitudinal axis from the fuel feed chamber (21) to a distal end (37) of the central body. An outer sleeve (35) surrounds the central body and forms an annular premixing chamber (43) between the outer sleeve and the central body. The hub includes a distal tip protruding outside the annular pre-mix chamber beyond the distal end of the outer sleeve.

Inventors

• EGIDIO PUCCI
• S Gori
• R. MELONI

Assignees

• 诺沃皮尼奥内技术股份有限公司

Dates

Publication Date

20260505

Application Date

20220510

Priority Date

20210512

Claims (20)

1. 1. A fuel injector for a gas turbine engine, the fuel injector comprising: a fuel feed chamber comprising an end wall; a central body extending along a longitudinal axis from the end wall to a distal end of the central body, the central body forming a distal tip and having a fuel injection port; an outer sleeve surrounding the central body and extending along the longitudinal axis of the central body from the end wall to a distal end of the outer sleeve opposite the fuel feed chamber; An annular pre-mix chamber disposed between the outer sleeve and the central body, the annular pre-mix chamber including an annular outlet at the distal end of the outer sleeve; An air inlet port extending through the outer sleeve and in fluid communication with the annular premix chamber, and A fuel conduit in the central body in fluid communication with the fuel feed chamber and the annular pre-mix chamber; wherein the distal tip protrudes outside the annular pre-mix chamber beyond the distal end of the outer sleeve; wherein the distal tip has a convex outer surface of tapered shape, an Wherein the fuel injection ports allow fuel flow from the fuel conduit to the annular pre-mix chamber.
2. 2. The fuel injector of claim 1, wherein the convex outer surface of the distal tip is a rotating surface coaxial with the central body.
3. 3. The fuel injector of claim 1, wherein the distal tip has one of a dome shape, a spherical cup shape, a hemispherical shape, an oval shape.
4. 4. The fuel injector of claim 1, wherein the premixing chamber has a converging distal portion with a cross-sectional area that tapers in a proximal-to-distal direction until the annular outlet of the premixing chamber.
5. 5. The fuel injector of claim 1, wherein the central body has a distal portion terminating in the distal tip and having a tapered shape with a cross-section that increases toward the distal tip.
6. 6. The fuel injector of claim 1, wherein the central body has a main body portion located within the premixing chamber, and wherein the main body portion and the distal tip are connected by a smooth transition region tapering toward the distal end of the central body.
7. 7. The fuel injector of claim 1, wherein the central body has a main body portion located within the premixing chamber, wherein the main body portion is connected to the distal tip along a transition region tapering toward the distal end of the central body, and wherein the transition region is formed by a surface created by a bus bar having a continuous derivative.
8. 8. The fuel injector of claim 1, wherein the center body comprises: A first portion proximate the end wall of the fuel feed chamber and extending toward the distal tip of the central body, and a second portion between the first portion and the distal tip; Wherein the first portion has a cylindrical shape with a circular cross-section, and Wherein the second portion has a tapered shape having a circular cross-section and a diameter that increases from the first portion to the distal tip.
9. 9. The fuel injector of claim 1, wherein the center body and the outer sleeve are coaxial.
10. 10. The fuel injector of claim 1, wherein the center body and the outer sleeve are non-coaxial and the annular pre-mix chamber has a radial dimension that varies about the longitudinal axis of the center body.
11. 11. The fuel injector of claim 1, wherein the central body includes additional fluid conduits, at least one of the additional fluid conduits extending along the central body and fluidly coupled to an outlet port at the distal tip of the central body.
12. 12. The fuel injector of claim 11, wherein the additional fluid conduit is adapted to convey at least one of combustion air, fuel, or an air/fuel mixture to the at least one outlet port.
13. 13. The fuel injector of claim 11, wherein the outlet port is positioned on the longitudinal axis of the center body.
14. 14. The fuel injector of claim 11, further comprising: A plurality of outlet ports fluidly coupled with the additional fluid conduit, distributed according to a circular arrangement about the axis of the central body.
15. 15. The fuel injector of claim 11, further comprising: a further additional fluid conduit extending along the central body and fluidly coupled to a further outlet port at the distal end of the central body; wherein the further additional fluid conduit is adapted to deliver fuel to the further outlet port.
16. 16. A fuel nozzle for a gas turbine engine, the fuel nozzle comprising the fuel injector of claim 1.
17. 17. The fuel nozzle of claim 16, wherein the fuel nozzle comprises a plurality of fuel injectors according to claim 1.
18. 18. The fuel nozzle of claim 17, further comprising: a front wall, wherein the outer sleeve of the fuel injector is connected to the front wall.
19. 19. The fuel nozzle of claim 17, wherein the fuel injectors are parallel to each other.
20. 20. The fuel nozzle of claim 17, wherein at least two of the fuel injectors have converging axes.

Description

Fuel injector and fuel nozzle for a gas turbine and gas turbine engine comprising such a nozzle Technical Field The subject matter disclosed herein relates generally to gas turbine engines. More specifically, the present disclosure relates to premix fuel nozzles for gas turbine engine combustors, and gas turbine engine combustors. Background Gas turbine engines for both aircraft and industrial applications include at least one combustor in which fuel in gaseous or liquid form is mixed with a compressed air stream and combusted to produce a hot pressurized combustion gas stream. The combustion gases are expanded in a turbine comprising one or more turbine stages to produce mechanical power. A portion of the mechanical power generated by the turbine is used to drive a compressor of the gas turbine engine and to support a continuous supply of combustion air to the combustor. The remaining available power is used to drive a load (such as a generator or compressor) or to generate thrust for propulsion of the aircraft. The combustor includes a combustion chamber and a plurality of fuel nozzles having the function of introducing liquid or gaseous fuel into a compressed air stream from an air compressor and obtaining a mixture of combustion air and fuel. At start-up, the mixture is ignited to burn the fuel. By continuously supplying compressed air and fuel to the combustor, a combustion process is maintained to produce a continuous flow of compressed hot combustion gases to operate the turbine. Control of the flame in the combustor is one of the key aspects of fuel nozzle design. One of the objectives of nozzle design is to reduce harmful emissions such as nitrogen oxides (NOx), carbon monoxide and unburned hydrocarbons. Other concerns are reduced flame instability, reduced acoustic pressure fluctuations or oscillations (i.e. combustion noise) and reduced risk of lean blowout, and reduced formation of hot spots in the combustion chamber, for example due to asymmetric temperature distribution. In this case, an important aspect is the stability of the shape and spatial position of the flame. Variations in flame shape and flame position during combustor operation may adversely affect the harmful emissions of the gas turbine engine and increase acoustic pressure variations and oscillations. Accordingly, improved fuel nozzle designs that aim to reduce flame instability in shape and location would be welcomed in the art. Disclosure of Invention In embodiments disclosed herein, a fuel injector includes a fuel feed chamber having an end wall and a central body extending along a longitudinal axis from the end wall to a distal end of the central body. An outer sleeve surrounds the central body and extends along an axis of the central body from the end wall to a distal end of the outer sleeve opposite the fuel feed chamber. Thus, an annular pre-mix chamber is defined between the outer sleeve and the central body. The premix chamber has an annular outlet at the distal end of the outer sleeve. The centerbody includes a distal tip terminating at a distal end of the centerbody and protruding outside the premixing chamber within the combustion chamber beyond a distal end of the outer sleeve. According to further embodiments disclosed herein, the central body has an additional fluid conduit extending along the central body and fluidly coupled to at least one outlet port at the distal tip of the central body. In use, depending on the operating conditions of the gas turbine in which the fuel injector is located, fuel, air or an air/fuel mixture may be delivered through the additional fluid conduit towards the distal tip of the centerbody. The outlet ports may be disposed on the axis of the centerbody or in an off-axis position. In some embodiments, more than one outlet port may be provided. According to another aspect, disclosed herein is a fuel nozzle for a gas turbine engine, the fuel nozzle comprising one or more fuel injectors as described above. The present disclosure also relates to a combustor assembly for a gas turbine engine. In one embodiment, the burner assembly has a combustion chamber extending from an upstream end to a downstream end. The downstream end is adapted to be fluidly coupled to a turbine of a gas turbine engine, and the upstream end is further adapted to be fluidly coupled to an air compressor of the gas turbine engine. The burner assembly also has at least one fuel nozzle as described above. Also disclosed herein is a gas turbine engine including a combustor assembly. In this specification and the appended claims, the terms "upstream" and "downstream" refer to the direction of air, fuel or an air-fuel mixture unless otherwise specified. Drawings Referring now briefly to the drawings in which: FIG. 1 is a schematic illustration of a gas turbine engine suitable for use in various useful applications, including industrial applications; FIG. 2 is a schematic cross-sectional view of a combustor with a plurality o