BURNER FOR A GAS TURBINE, AND A GAS TURBINE

Abstract

A burner for a gas turbine, having a burner lance and/or burner hub, a burner passage which at least partially surrounds the burner lance and/or burner hub, and a fuel supply arrangement having at least one fuel nozzle and at least one fuel channel. The burner allows pollutant emissions to be reduced and offers a high degree of operational safety. The fuel supply arrangement has a fluidic oscillator that has an interaction chamber, the interaction chamber having at least one inlet and, lying opposite, one outlet region that has at least one outlet channel, one end of at least one feedback line terminating into the interaction chamber in the region of the inlet, the other end thereof terminating into the outlet region or into an outlet channel, and each end of the feedback line being sealed off from the interaction chamber by a flexible membrane.

Claims

1. A burner for a gas turbine, comprising: at least one burner lance and/or burner hub, at least one burner passage that at least portionally surrounds the burner lance and/or burner hub, a fuel supply arrangement, having at least one fuel nozzle and at least one fuel channel, wherein the fuel supply arrangement comprises at least one fluidic oscillator that has an interaction chamber, wherein the interaction chamber has at least one inlet for the intake of fuel and, located opposite, an outlet region, having at least one outlet channel for the outlet of fuel, wherein one end of at least one feedback line leads into the interaction chamber, in the region of the inlet, and the other end thereof leads into the outlet region or into an outlet channel, wherein the two ends of the feedback line are each sealed off from the interaction chamber by a flexible membrane.

2. The burner as claimed in claim 1, wherein the membrane is composed of a temperature-resistant high-grade steel or of a nickel-based material.

3. The burner as claimed in claim 1, wherein the feedback line is filled with a fluid or gel for the purpose of transmitting a pressure.

4. The burner as claimed in claim 1, wherein at least one outlet channel of the interaction chamber is realized as a fuel nozzle in the form of a full-jet nozzle.

5. The burner as claimed in claim 1, wherein, for the purpose of stimulating the oscillation, the interaction chamber comprises at least two oppositely disposed side-wall regions, which diverge from each other in the manner of a diffusor, at least in the inlet region of the interaction chamber, in the direction of the outlet region.

6. The burner as claimed in claim 5, wherein the two side-wall regions diverge in such a manner that at least an angle of 7.5 degrees is realized between an inflow direction and the side-wall region.

7. The burner as claimed in claim 5, wherein the two opposing side-wall regions extend in a curved shape from the inlet region to the outlet region.

8. The burner as claimed in claim 1, wherein the interaction chamber is realized so as to be substantially rotationally symmetrical, and the rotation axis goes through the inlet and the opposite outlet region, wherein the interaction chamber widens in the manner of a diffusor, at least in the inlet region, in the direction of the outlet region.

9. A fluidic oscillator having comprising: an interaction chamber, wherein the interaction chamber has at least one inlet for the intake of a fluid and, located opposite, an outlet region, having at least one outlet channel for the outlet of the fluid, wherein, for the purpose of stabilizing an oscillation of the fluid jet that can be stimulated by the interaction chamber, one end of at least one feedback line leads into the interaction chamber, in the region of the inlet, and the other end thereof leads into the outlet region or into an outlet channel, wherein the ends of the feedback line are each sealed off from the interaction chamber by a flexible membrane.

10. The fluidic oscillator as claimed in claim 9, wherein the membrane is composed of a temperature-resistant high-grade steel or of a nickel-based material.

11. The fluidic oscillator as claimed in claim 9, wherein the feedback line is filled with a fluid or gel for the purpose of transmitting a pressure.

12. The fluidic oscillator as claimed in claim 9, wherein, for the purpose of stimulating the oscillation, the interaction chamber comprises at least two oppositely disposed side-wall regions, which diverge from each other in the manner of a diffusor, at least in the inlet region of the interaction chamber, in the direction of the outlet region.

13. The fluidic oscillator as claimed in claim 9, wherein at least one outlet channel is realized as a fuel nozzle in the form of a full-jet nozzle.

14. A combustion chamber for a gas turbine having comprising: at least one burner, wherein the at least one burner is realized as claimed in claim 1.

15. A gas turbine comprising: at least one combustion chamber, wherein the at least one combustion chamber is realized as claimed in claim 14.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] There are shown in

[0053] FIG. 1 a schematic representation of a gas turbine of the prior art, in a longitudinal section,

[0054] FIG. 2 a schematic representation of a first type of a fluidic oscillator according to the prior art, in a longitudinal section,

[0055] FIG. 3 a schematic representation of a burner according to the prior art, in a longitudinal section,

[0056] FIG. 4 a schematic representation of a combustion chamber according to the prior art, in a longitudinal section,

[0057] FIG. 5 a schematic representation of a burner of the combustion chamber represented in FIG. 4, in a longitudinal section,

[0058] FIG. 6 a schematic representation of a fluidic oscillator according to the invention, according to a first exemplary embodiment, in a longitudinal section, and

[0059] FIG. 7 a schematic representation of a burner according to the invention, according to a second exemplary embodiment, in a longitudinal section.

DETAILED DESCRIPTION OF INVENTION

[0060] FIG. 1 shows a sectional view of a gas turbine 1 according to the prior art, in a schematically simplified representation. In its interior, the gas turbine 1 has a rotor 3, which is mounted so as to be rotatable about a rotation axis 2, and which has a shaft 4, which is also referred to as a turbine rotor. Along the rotor 3, in succession, there is an intake housing 6, a compressor 8, a combustion system 9, having one or more combustion chambers 10, which each comprise a burner arrangement having burners 11, a fuel supply system (not represented) for the burners, and a combustion chamber housing 12, and a turbine 14 and an exhaust-gas housing 15. The combustion chamber 10 may be, for example, an annular combustion chamber. However, the invention may also relate to gas turbines that are realized as a turbomachine having a plurality of annular combustion chambers. The invention may also relate to gas turbines having one or more pipe or silo combustion chambers. The pipe combustion chambers may be disposed, for example, in the form of a ring at the turbine inlet.

[0061] The combustion system 9 represented in FIG. 1 communicates with a, for example annular, hot-gas channel. There, a plurality of turbine stages connected in succession constitute the turbine 14. Each turbine stage is constituted by blade rings. As viewed in the direction of flow of a working medium, in the hot channel a row of guide blades 17 is succeeded by a row of rotor blades 18. The guide blades 17 in this case are fastened to an inner housing of a stator 19, whereas the rotor blades 18 of a row are attached, for example by means of a turbine disc, to the rotor 3. A generator (not represented), for example, is coupled to the rotor 3.

[0062] During operation of the gas turbine, air is sucked in through the intake housing 6 and compressed by the compressor 8. The compressor air L″ provided at the turbine-side end of the compressor 8 is guided along a burner plenum 7 to the combustion system 9 where, in the region of the burner arrangement, it is routed into the burners 11 and in the latter is mixed with fuel and/or enriched with fuel in the outlet region of the burner 11. Fuel supply systems in this case supply the burners with fuel. The mixture, or the compressor air and the fuel, is/are discharged from the burners 11 into the combustion chamber 11 and combusts/combust, forming a hot stream of working gas in a combustion zone within the combustion chamber housing 12 of the combustion chamber. From there, the stream of working gas flows along the hot-gas channel, past the guide blades 17 and the rotor blades 18. At the rotor blades 18, the stream of working gas expands in an impulse-transmitting manner, such that the rotor blades 18 drive the rotor 3, and the latter drives the generator (not represented) coupled thereto.

[0063] FIG. 2 shows a fluidic oscillator of a first type according to the prior art, in longitudinal section.

[0064] The oscillator 24a comprises an interaction chamber 26, having precisely one inlet 28 that has an inlet region 30, and having an oppositely disposed outlet region 32 that has a first outlet channel 34 and a second outlet channel 36. Disposed for each outlet channel there is a relatively thin feedback line 38 that connects the inlet region to the outlet region, one end of the feedback line leading into the outlet channel in the example represented. The side-wall regions 40 diverge in the direction of the outlet region 32, such that the interaction chamber 26 is triangular in longitudinal section. The oscillator 24a is not of a rotationally symmetrical structure, but is of a constant longitudinal section perpendicularly in relation to the plane of the drawing.

[0065] Shown schematically in FIG. 3 is a burner 90 according to the prior art, in a longitudinal section. The burner 90 has a central burner axis 66, and a burner passage 100 that at least portionally surrounds the burner axis 66. The burner passage 100 is realized as premix passage 92 in the form of an annular space, and radially outwardly is delimited by a wall 70, the burner passage 100 being delimited radially inwardly by a centrally disposed burner hub 94. Disposed in the premix passage 92 is a diagonal grating 96 that imparts a swirl to the compressor air L″ flowing in the premix passage. The diagonal grating is composes of a number of fuel injectors 98, which are disposed all around the hub and whose main bodies, disposed in the premix passage, impart a velocity component, going in the circumferential direction of the passage, to the compressor air L″ flowing past. Extending in the burner hub 94 there is a fuel supply arrangement 73, which comprises the fuel nozzles 80, the fuel channel 82 (which may be realized all the way round in the cone of the burner hub) and supply lines (not represented), the supply lines branching off from the fuel channel 82 and extending as far as the fuel nozzles 80, for the purpose of supplying the fuel nozzles.

[0066] Shown schematically in FIG. 4 is a portion of a combustion chamber 10 of the prior art, having a burner arrangement 48 at a top end of the combustion chamber. The combustion chamber comprises a combustion-chamber wall, having a flame tube 50 that comprises a combustion zone, and having a transition piece 52 that adjoins the flame tube and extends as far as a turbine inlet of the gas turbine. For the purpose of damping thermoacoustic oscillations that occur during operation, resonators 54 are disposed, at the level of the flame, on the combustion chamber wall. The burner arrangement 48 comprises a central pilot burner 56, having a central burner lance 58, and having a burner passage 60 that is realized as a pilot-burner premix passage. The pilot burner 56 comprises a pilot cone 62 that widens conically in the direction of flow. Main burners 64 are disposed in the form of a circle around the central pilot burner. The main burners 64 each have a burner axis 66 and a burner passage 68 that is disposed coaxially in relation to the burner axis, the burner passage 68 being delimited radially outwardly by a wall 70, and when in operation being able to have a through-flow of compressor air L″, and serving to mix fuel and air L″, there being disposed in the burner passage 68 a central burner lance 72 and a number of fuel injectors that extend from the burner lance in the direction of the wall 70 and that are fluidically connected to a fuel supply arrangement (not represented) extending, at least partially, in the burner lance 72, and that have fuel nozzles. The fuel injectors are realized as swirl blades of a swirl generator 74, fuel nozzles being disposed on the swirl blades.

[0067] Shown schematically in FIG. 5 is a main burner 64 of the burner arrangement of FIG. 4, in longitudinal section. The burner 64 has a central burner axis 66, and a burner passage 68 disposed coaxially in relation to the burner axis 66, the burner passage being delimited radially outwardly by a wall 70, and when in operation being able to have a through-flow of compressor air L″, and serving to mix fuel and air L″. A central burner lance 72 and a number of fuel injectors 79 are disposed in the burner passage. The fuel injectors 79 each comprises a main body 71, disposed in the premix passage, that is realized as swirl blades 76 of a swirl generator 74. The fuel injectors 79 comprise fuel nozzles 80 that open into the burner passage 68, at the surface of the swirl blades 76. In order to be supplied with fuel, the fuel nozzles 80 are fluidically connected to a fuel supply arrangement 73. The fuel supply arrangement 73 comprises a fuel channel 82, extending in the burner lance, and fuel supply channels 78, which extend into the swirl blades 76, as far as the respective fuel nozzles 80.

[0068] Shown schematically in FIG. 6 is a fluidic oscillator 25 according to the invention according to a first exemplary embodiment, in a longitudinal section. The fluidic oscillator 25 comprises an interaction chamber 26 that is realized so as to be rotationally symmetrical about a rotation axis 31. The inlet 28, with an inlet region 30, is disposed at one end of the chamber, the outlet region 32, with two outlet channels 34 and 36, being disposed oppositely. The side-wall regions 27 extend from the inlet to the outlet region, diverging, at least in the inlet region 30, in the direction of the outlet, advantageously at an angle α>7.5 degrees. Provided for each outlet channel there is a feedback line 38a, 38b, one end of each of which leads, in the region of the inlet 28, into the interaction chamber, and the other end of which leads into the outlet region 32, the two ends of the feedback line 38 each being sealed off from the interaction chamber by a respective flexible membrane 37.

[0069] A jet of fuel under pressure entering the interaction chamber 26 in the inflow direction 29 advantageously is applied to the side walls 27, an oscillation of the jet being stimulated because of the divergence of the side-wall regions 27 in the inlet region 30, such that the jet is periodically applied to differing side-wall regions and periodically applies fuel to the two outlet channels 34 and 36. The feedback lines 38a, 38b feed a pressure in the outlet region 32 back to the inlet region 30, and thereby stabilize the oscillation. In order that no fuel gets into the feedback lines, the feedback lines are sealed at their ends by the flexible membranes 37, which transmit a pressure to a fluid 35 or gel, which may be, for example, air or an inert gas, enclosed in each feedback line. When, during the oscillation, fuel is applied to the outlet channel 34, the membrane 37 of the feedback channel 38a that is disposed in the outlet region is pressed into the line 38a, as represented, such that the membrane 37 at the other end of the feedback line 38a, in the inlet region 30, is pressed out. At this time, substantially no pressure is applied to the two membranes 37 that seal off the opposite feedback line 38b. Owing to the membrane 37, the fluidic oscillator 25 is suitable for having a through-flow of fuel and for stimulating oscillation of the fuel jet, a safety risk, from standing fuel in the feedback lines, being reliably avoided.

[0070] A burner 84 according to the invention, according to a second exemplary embodiment of the invention, is shown schematically in FIG. 7, in longitudinal section. Unlike the burner 64 of the prior art represented in FIG. 5, the fuel supply arrangement 73 has at least one fluidic oscillator 85 having an interaction chamber 26, an inlet 28 of the interaction chamber being connected to the fuel channel 82 of the fuel supply arrangement 73. Opposite the inlet region 30, the interaction chamber 26 has an outlet region 32 having two outlet channels 34 and 36. A first outlet channel 34 extends as far as a first group of fuel nozzles 80a in a first fuel injector 79a. A second outlet channel 36 extends as far as a second group of fuel nozzles 80b in an oppositely disposed fuel injector 79b, the fluidic oscillator 85 comprising a feedback line 38a, 38b for each outlet channel, one end of the feedback line 38a, 38b leading into the respective outlet channel 34, 36 downstream from the fuel nozzles 80a, 80b that the outlet channel comprises, and the other end leading into the inlet region 30 of the interaction chamber 26.

[0071] The pressure prevailing at the end of the outlet channel is fed back to the inlet region 30 of the interaction chamber by the feedback lines 38a, 38b. The membranes 37 seal off the feedback lines against the fuel, a pressure loading the membranes being transmitted from one end to the other end of the feedback line by means of a fluid or gel enclosed in the feedback line.