BURNER COMPRISING A FLUIDIC OSCILLATOR, FOR A GAS TURBINE, AND A GAS TURBINE COMPRISING AT LEAST ONE SUCH BURNER

Abstract

A burner having a pre-mixing passage delimited radially outwardly by a wall, a burner lance and a plurality of fuel injectors arranged in the pre-mixing passage, the injectors extending from the burner lance in the direction of the wall and having fuel nozzles. The fuel supply arrangement has at least one fluidic oscillator that has an interaction chamber, an inlet to the interaction chamber connected to a fuel channel of the fuel supply arrangement, a first outlet channel of the interaction chamber extending at least to a first fuel nozzle and a second outlet channel extending at least to a second fuel nozzle, the fluidic oscillator has one feedback line for each outlet channel, one end of the feedback line terminating into the respective outlet channel downstream of the at least one fuel nozzle, and the other end thereof terminating into an inlet region of the interaction chamber.

Claims

1. A burner comprising: a central burner axis and a premix passage enclosing the burner axis at least in sections, the premix passage being bounded radially outward by a wall, being capable of being flowed through during operation by compressor air, and being used to mix fuel and air, there being arranged in the premix passage a burner lance or burner hub and a number of fuel injectors which extend from the burner lance or burner hub in the direction of the wall and comprise fuel nozzles fluidically connected to a fuel feed arrangement at least partially contained by the burner lance or burner hub, wherein the fuel feed arrangement comprises at least one fluidic oscillator having an interaction chamber, an input of the interaction chamber being connected to a fuel channel of the fuel feed arrangement, and a first output channel of the interaction chamber extending at least to a first fuel nozzle and a second output channel extending at least to a second fuel nozzle, the fluidic oscillator comprising one feedback line per output channel, the feedback line opening with one of its ends into the respective output channel in the region downstream of the at least one fuel nozzle and with the other end into an input region of the interaction chamber.

2. The burner as claimed in claim 1, wherein the first output channel extends to a first group of fuel nozzles and the second output channel extends to a second group of fuel nozzles, the feedback line respectively opening into the respective output channel in a region downstream of the respective group of fuel nozzles.

3. The burner as claimed in claim 1, wherein the feedback line connects to the output channel downstream of the at least one fuel nozzle.

4. The burner as claimed in claim 1, wherein the at least first fuel nozzle and the at least second fuel nozzle are arranged in different fuel injectors.

5. The burner as claimed in claim 1, wherein the two fuel injectors are essentially arranged opposite one another on the burner lance.

6. The burner as claimed in claim 4, wherein the burner comprises more than two groups of fuel nozzles, connected to the fluidic oscillator in this way, in different fuel injectors.

7. The burner as claimed in claim 6, wherein the different fuel injectors are arranged circumferentially on the burner lance, and the associated output channels are arranged circumferentially on the interaction chamber.

8. The burner as claimed in claim 1, wherein the at least one fuel injector comprises a base body, on which the fuel nozzles contained by the fuel injector are arranged.

9. The burner as claimed in claim 1, wherein the interaction chamber comprises the input at one of its ends and an output region at an opposite end, and is bounded by side walls or side-wall regions which extend from the input of the chamber to the output region comprising the outputs, at least two oppositely arranged side walls or side-wall regions diverging in the direction of the output region, at least in the input region.

10. The burner as claimed in claim 1, wherein at least two oppositely arranged side-wall regions diverge in the input region of the interaction chamber in the direction of the output region at an angle of more than 7.5 degrees with respect to an influx direction of the input of the interaction chamber.

11. The burner as claimed in claim 1, wherein the interaction chamber is essentially configured rotationally symmetrically, the interaction chamber widening at least in the input region in the manner of a diffuser in the direction of the output region.

12. A burner arrangement comprising: a number of burners, with main burners being arranged in one or more circles arranged concentrically with one another, wherein at least one burner is configured as claimed in claim 1.

13. A combustion chamber for a gas turbine, comprising: at least one burner as claimed in claim 1.

14. A gas turbine comprising: at least one combustion chamber, wherein the combustion chamber is configured as claimed in claim 13.

15. The burner as claimed in claim 8, wherein the base body comprises a swirl impeller of a swirl generator.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] FIG. 1 schematically shows a gas turbine of the prior art in a longitudinal section,

[0052] FIGS. 2, 3 schematically show two types of fluidic oscillator according to the prior art in a longitudinal section,

[0053] FIG. 4 schematically shows a detail of a combustion chamber 10 of the prior art in a longitudinal section,

[0054] FIG. 5 schematically shows a main burner of the burner arrangement represented in FIG. 4 in a longitudinal section,

[0055] FIG. 6 schematically shows a burner according to the invention according to a first exemplary embodiment of the invention in a longitudinal section, and

[0056] FIG. 7 schematically shows a burner according to the invention according to a second exemplary embodiment of the invention in a longitudinal section.

DETAILED DESCRIPTION OF INVENTION

[0057] FIG. 1 shows a sectional view of a gas turbine 1 according to the prior art in a schematically simplified representation. The gas turbine 1 internally comprises a rotor 3 which is mounted so as to rotate about a rotation axis 2, has a shaft 4 is also referred to as the turbine rotor. Successively along the rotor 3, there are an intake manifold 6, a compressor 8, a combustion system 9 having a number of combustion chambers 10, each of which comprises a burner arrangement having burners 11, a fuel supply system (not represented) for the burners and a housing 12, a turbine 14 and an exhaust manifold 15. The combustion chamber 10 may, for example, be a ring combustion chamber. The gas turbine could however also comprise tube combustion chambers, which are for example arranged annularly at the turbine entry.

[0058] The combustion system 9 communicates with an e.g. annular hot-gas channel. There, a plurality of turbine stages connected in series form the turbine 14. Each turbine stage is formed from blade rings. As seen in the flow direction of a working medium, a row formed by the guide vanes 17 is followed in the hot channel by a row formed by rotor blades 18. The guide vanes 17 are in this case fastened on an inner housing of a stator 19, while the rotor blades 18 of a row are fitted on the rotor 3, for example by means of a turbine disk. Coupled to the rotor 3, there is for example a generator (not represented).

[0059] During operation of the gas turbine, air is taken in by the compressor 8 through the intake manifold 6 and compressed. The compressor air L″ provided at the end of the compressor 8 on the turbine side is guided along a burner plenum 7 to the combustion system 9, where it is guided into the burners 11 in the region of the burner arrangement and mixed with fuel in them and/or enriched with fuel in the exit region of the burner 11. Fuel supply systems in this case supply the burners with fuel. The mixture, i.e. the compressor air and the fuel, are introduced into the combustion chamber 10 by the burners 11 and burn while forming a hot working-gas flow in a combustion zone inside the combustion-chamber housing 12 of the combustion chamber. From there, the working-gas flow flows along the hot-gas channel past the guide vanes 17 and the rotor blades 18. At the rotor blades 18, the working-gas flow expands by imparting momentum, so that the rotor blades 18 drive the rotor 3 and the generator (not represented) coupled to it.

[0060] FIG. 2 shows a fluidic oscillator of a first type according to the prior art in longitudinal section.

[0061] The oscillator 24a comprises an interaction chamber 26 having an input 28 with an input region 30 and an oppositely arranged output region 32 with a first output 34 and a second output 36. A relatively thin feedback line 38, which connects the input region to the output region, is arranged at each output.

[0062] The side-wall regions 40 diverge in the direction of the output, so that the interaction chamber 26 has a triangular longitudinal section. The oscillator 24a is not constructed rotationally symmetrically, but has a constant longitudinal section perpendicularly to the plane of the drawing.

[0063] FIG. 3 shows a fluidic oscillator 24b of a second type according to the prior art in longitudinal section. The oscillator 24b is likewise not constructed rotationally symmetrically, but has a constant longitudinal section perpendicularly to the plane of the drawing. The input 28 is arranged inside a guide means 42 centrally in the interaction chamber 26, so that a jet entering under pressure is guided frontally onto the opposite side wall 44. The jet alternately flows leftward and rightward at the guide means in the direction of the output region 32, while alternately applying the fluid to the outputs 34 and 36, so that the jet emerges from the chamber alternately through one output and the other, with a frequency which is determined by the size of the interaction chamber 26.

[0064] FIG. 4 schematically shows a detail of a combustion chamber 10 of the prior art with a burner arrangement 48 at a head end of the combustion chamber. The combustion chamber comprises a combustion-chamber wall having a flame tube 50 comprising a combustion zone, and having a transition piece 52 which follows on from the flame tube and extends to a turbine entry of the gas turbine. In order to dampen thermoacoustic oscillations which occur during operation, resonators 54 are arranged at the level of the flame on the combustion-chamber wall. The burner arrangement 48 comprises a central pilot burner 56 having a central pilot-burner lance 58 and a pilot-burner premix passage 60. The pilot burner 56 comprises a pilot cone 62 widening conically in the flow direction. Main burners 64 are arranged circularly around the central pilot burner. The main burners 64 each have a burner axis 66 and a premix passage 68 arranged concentrically with the burner axis; the premix passage 68 is bounded radially outward by a wall 70, compressor air L″ can flow through it during operation, and it is used to mix fuel and air L″, the premix passage 68 containing a central burner lance 72 and a number of fuel injectors, which extend from the burner lance in the direction of the wall 70, are connected fluidically to a fuel feed arrangement which the burner lance 72 comprises, and have fuel nozzles. The fuel injectors are configured as swirl impellers of a swirl generator 74, fuel nozzles being arranged on the swirl impellers.

[0065] FIG. 5 shows a main burner 64 of the burner arrangement of FIG. 4 schematically in longitudinal section. The burner 64 has a central burner axis 66 and a premix passage 68 enclosing the burner axis at least in sections; the premix passage is bounded radially outward by a wall 70, compressor air L″ can flow through it during operation, and it is used to mix fuel and air. The premix passage 68 contains a central burner lance 72 and a number of fuel injectors 79. The fuel injectors 79 each comprise a base body 71, which is arranged in the premix passage and is configured as swirl impellers 76 of a swirl generator 74. The fuel injectors 79 comprise fuel nozzles 80, which open into the premix passage 68 on the surface of the swirl impellers 76. The fuel nozzles 80 are fluidically connected to a fuel feed arrangement 73 in order to be supplied with fuel. The fuel feed arrangement 73 comprises a fuel channel 82 extending in the burner lance, and fuel feed channels 78 which extend into the swirl impellers 76 as far as the respective fuel nozzles 80.

[0066] FIG. 6 schematically shows a burner 84 according to the invention in longitudinal section according to a first exemplary embodiment of the invention. In contrast to the burner 64 of the prior art as represented in FIG. 5, the fuel feed arrangement 73 has at least one fluidic oscillator 85 with an interaction chamber 26, an input 28 of the interaction chamber being connected to the fuel channel 82 of the fuel feed arrangement 73. Opposite the input region 30 with input 28, the interaction chamber 26 has an output region 32 with two outputs 34 and 36. A first output channel 86 extends from the output 34 to a first group of fuel nozzles 80a in a first fuel injector 79a. A second output channel 88 extends from the output 36 to a second group of fuel nozzles 80b in a fuel injector 79b arranged opposite, the fluidic oscillator 85 comprising a feedback line 38a, 38b for each output channel, the feedback line 38a, 38b opening with one of its ends into the respective output channel 86, 88 downstream of the fuel nozzles 80a, 80b which the output channel comprises, and with the other end into the input region 30 of the interaction chamber 26.

[0067] If the input 28 of the fluidic oscillator 85 is supplied with a pressurized fuel flow by means of the fuel channel 82 during operation of the burner, the fuel flow in the interaction chamber 26 will be excited into oscillating application on the side walls of the chamber because of the diverging side walls in the input region 30, and will therefore supply the outputs 34 and 36 alternately with fuel. The fuel flows to the respective fuel nozzle groups through the output channels 86, 88, so that a pulsating fuel flow is injected from the latter into the premix passage 68. The fuel nozzles may, for example, be full-jet nozzles or pressure-swirl nozzles. The feedback line 38a is connected downstream of the fuel nozzles 80a to the output channel 86 and couples the pressure prevailing at the end of the output channel back to the input region 30 of the interaction chamber. The pressure prevailing at the end of the output channel is in this case influenced by the pressure in the premix passage immediately before the fuel nozzles 80a, so that when there is a high pressure in this region the fuel supply is switched over to the second group of fuel nozzles 80b more slowly than would be the case with a lower pressure. The group of fuel nozzles will therefore inject fuel for a longer time into the compressor air flow flowing past, before which the pressure in the premix passage is higher, so that a more uniform fuel concentration is set up at the output of the burner even when there are different pressure conditions on the two sides of the burner lance 72. This counteracts creation of pressure pulsations and reduces the production of pollution emissions.

[0068] FIG. 7 schematically shows a burner 90 according to the invention according to a second exemplary embodiment of the invention. The burner 90 has a central burner axis 66, a premix passage 92, which is in the form of a ring space, extends concentrically with the burner axis 66, and is bounded outward by a wall 70, and a centrally arranged burner hub 94. Arranged in the premix passage 92, there is a diagonal grid 96 which imparts a swirl to the compressor air L″ flowing in the premix passage. The diagonal grid consists of a number of fuel injectors 98, which are arranged circumferentially around the hub and whose base bodies arranged in the premix passage impart a velocity component pointing in the circumferential direction of the passage to the compressor air L″ flowing past. Extending in the burner hub 94, there is at least one fuel channel 82, which may be formed circumferentially in the cone of the burner hub and via which fuel nozzles 80, 80a, 80b of the fuel injectors 98 are supplied with fuel. According to the exemplary embodiment, at least two output channels of a fluidic oscillator (not represented) extend in at least one fuel injector 100. The fluidic oscillator is fluidically arranged between the fuel channel 82 and at least a first and a second group of fuel nozzles, which are supplied with fuel in the fuel injector 100 via a first and a second output channel (not represented) of the fluidic oscillator. The fuel nozzles of the first group are denoted by 80a and are arranged on the hub side on the fuel injector, the fuel nozzles of the second group being denoted by 80b and injecting fuel into the premix passage radially further outward on the fuel injector. The exemplary embodiment makes it possible to obtain a fuel concentration which is homogeneous in the radial direction at the output of the premix passage even in the event of different flow speeds or pressure conditions in the outer region, i.e. the region on the hub side, of the premix passage.