FUEL NOZZLE ASSEMBLY FOR REDUCING MULTIPLE TONE COMBUSTION DYNAMICS
A fuel nozzle assembly includes a center body comprising an outer sleeve and an internal fuel passage defined within the outer sleeve. The internal fuel passage defines a fuel flow path within the center body and includes an inlet defined at an upstream end of the center body. The inlet is formed to receive fuel from a fuel supply. The fuel nozzle assembly also includes a plurality of vanes that extend radially outwardly from the outer sleeve and at least one of the vanes includes at least one fuel port that is in fluid communication with the internal fuel passage. At least one baffle extends radially into the internal fuel passage downstream from the inlet and upstream from the at least one fuel port such that the at least one baffle reduces fuel flow area within the fuel flow path upstream from the at least one fuel port.
The present disclosure is generally directed to a fuel nozzle assembly for reducing multiple tone combustion dynamics. In particular embodiments, the fuel nozzle assembly may be incorporated into a combustion system of a gas turbine or other turbomachine.
BACKGROUNDGas turbines are widely used in industrial and power generation operations. A gas turbine generally includes, in serial flow order, a compressor, a combustion section and a turbine. The combustion section may include multiple combustors annularly arranged around an outer casing. In operation, a working fluid such as ambient air is progressively compressed as it flows through the compressor. A portion of the compressed working fluid is routed from the compressor to each of the combustors where it is mixed with a fuel and burned in a combustion chamber or zone to produce combustion gases. The combustion gases are routed through the turbine along a hot gas path where thermal and/or kinetic energy is extracted from the combustion gases via turbine rotors blades coupled to a rotor shaft, thus causing the rotor shaft to rotate and produce work and/or thrust.
During particular operating conditions, low frequency combustion tones with sufficient amplitudes, which are in-phase and coherent, may produce undesirable sympathetic vibrations in the turbine and/or other downstream components, thereby imposing undesirable and unnecessary restrictions on the function and operability of the combustor. Low frequency tones are commonly equivalence ratio driven tones. In other words, low frequency tones may result from fluctuations in air feed flow or fuel feed flow to a combustion zone within the combustor.
Typically, low frequency combustion tones are managed by employing known combustor tuning techniques. However, it has been found that conventional combustor tuning techniques may only be sufficient to address or control only a single dominant tone in the combustion system.
BRIEF DESCRIPTION OF THE TECHNOLOGYAspects and advantages are set forth below in the following description, or may be obvious from the description, or may be learned through practice.
One embodiment of the present disclosure is a fuel nozzle assembly. The fuel nozzle assembly includes a center body comprising an outer sleeve and an internal fuel passage defined within the outer sleeve. The internal fuel passage defines a fuel flow path within the center body and includes an inlet defined at an upstream end of the center body. The inlet is formed to receive fuel from a fuel supply. The fuel nozzle assembly also includes a plurality of vanes that extend radially outwardly from the outer sleeve and at least one of the vanes includes at least one fuel port that is in fluid communication with the internal fuel passage. At least one baffle extends radially into the internal fuel passage downstream from the inlet and upstream from the at least one fuel port such that the at least one baffle reduces fuel flow area within the internal fuel passage upstream from the at least one fuel port.
Another embodiment of the present disclosure is a combustion system. The combustion system includes an end cover that is coupled to an outer casing and that is in fluid communication with a fuel supply. A plurality of fuel nozzle assemblies is spaced radially and circumferentially across an inner surface of the end cover and includes a first fuel nozzle assembly that is in fluid communication with a first fuel circuit and a second fuel nozzle assembly in fluid communication with a second fuel circuit. The first fuel nozzle assembly includes a center body comprising an outer sleeve and an internal fuel passage defined within the outer sleeve. The internal fuel passage defines a fuel flow path within the center body. The internal fuel passage includes an inlet that is defined at an upstream end of the center body and that is in fluid communication with the first fuel circuit. A plurality of vanes extends radially outwardly from the outer sleeve and at least one of the vanes includes at least one fuel port that is in fluid communication with the internal fuel passage. The first fuel nozzle assembly further includes at least one baffle that extends radially into the internal fuel passage downstream from the inlet and upstream from the at least one fuel port. The at least one baffle reduces fuel flow area within the fuel flow path.
Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the specification.
A full and enabling disclosure of the of various embodiments, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:
Reference will now be made in detail to present embodiments of the disclosure, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the disclosure.
As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows. The term “radially” refers to the relative direction that is substantially perpendicular to an axial centerline of a particular component, and the term “axially” refers to the relative direction that is substantially parallel and/or coaxially aligned to an axial centerline of a particular component.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Low frequency tones observed in gas turbine combustion systems, particularly combustion systems having premix type fuel nozzle assemblies, are typically equivalence ratio driven tones. In other words, fluctuations from air flow path or fuel flow paths may drive these tones. Depending at least in part on the tones generated, flow area of fuel ports defined along vanes of the fuel nozzle assembly may be sized to address or mitigate possible negative effects of specific single tones. However, this tuning strategy has its limitations. For example, sizing the flow area of the fuel ports may only address one dominating tone present in the system.
Various embodiments provided herein allow for ‘mixed impedance’ tuning of the combustion system by providing a baffle or flow restriction plate within an internal fuel passage defined within a centerbody portion of a premix type fuel nozzle assembly. The baffle(s) are defined within the internal flow passage upstream from the fuel ports and downstream from a fuel inlet and/or a flow restrictor disposed upstream from the inlet to the internal fuel passage. The baffle can be placed so as to engineer the acoustic impedance and to reduce the equivalence ratio oscillations within the combustion system.
Each example is provided by way of explanation, not limitation. In fact, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present disclosure covers such modifications and variations as come within the scope of the appended claims and their equivalents. Although exemplary embodiments of the present disclosure will be described generally in the context of a fuel nozzle assembly and a combustion system for a land based power generating gas turbine combustor for purposes of illustration, one of ordinary skill in the art will readily appreciate that embodiments of the present disclosure may be applied to any style or type of combustor for a turbomachine and are not limited to combustors or combustion systems for land based power generating gas turbines unless specifically recited in the claims.
Referring now to the drawings,
During operation, air 26 flows through the inlet section 12 and into the compressor 14 where the air 26 is progressively compressed, thus providing compressed air 28 to the combustor 18. Fuel 30 from a fuel supply 32 is injected into the combustor 16, mixed with a portion of the compressed air 28 and burned to produce combustion gases 34. The combustion gases 34 flow from the combustor 18 into the turbine 20, wherein energy (kinetic and/or thermal) is transferred from the combustion gases 34 to rotor blades (not shown), thus causing shaft 24 to rotate. The mechanical rotational energy may then be used for various purposes such as to power the compressor 14 and/or to generate electricity. The combustion gases 34 exiting the turbine 20 may then be exhausted from the gas turbine 10 via the exhaust section 22.
The combustion system 16 may be any type of combustion system 16 known in the art, and the present disclosure is not limited to any particular combustion system design unless specifically recited in the claims. For example, the combustion system 16 may be a can-annular or an annular combustion system.
As shown in
The combustor 18 may also include one or more liners such as a combustion liner 44 and/or a transition duct 46 that at least partially define a combustion chamber or reaction zone 48 within the outer casing 36. The combustion liner 44 and/or the transition duct 46 may also at least partially define a hot gas path 50 for directing the combustion gases 34 into the turbine 20. In particular configurations, one or more flow or impingement sleeves 52 may at least partially surround the combustion liner 44 and/or the transition duct 46. The flow sleeve(s) 52 may be radially spaced from the combustion liner 44 and/or the transition duct 46 so as to define an annular flow path 54 for directing a portion of the compressed air 28 towards the head end portion 42 of the combustor 18.
In various embodiments, as shown in
Various embodiments of the combustor 18 may include different numbers and arrangements of the fuel nozzle assemblies 100 and is not limited to six fuel nozzle assemblies 100 as shown in
The fuel nozzle assemblies 100 may be divided into various groups or circuits to facilitate multiple fueling regimes over a range of operations of the gas turbine and/or the combustor 18. For example, in the exemplary arrangements shown in
During base load operations, all of the fuel lines 56, 58, 60 may be used to supply fuel to the fuel nozzle assemblies 100 in the combustor 18 (with respective fuel lines 56, 58, 60 supplying respective primary, secondary, and tertiary groupings of the fuel nozzle assemblies 100. Fuel flow may be reduced or completely eliminated from one or more groups of the fuel nozzle assemblies 100 during reduced or turndown operations via primary, secondary, and tertiary gas control valves (not shown) connected to the corresponding fuel lines 56, 58, 60. Furthermore, according to one aspect of the present disclosure, relative fuel flow to one or more of the fuel lines 56, 58, 60 may be varied at a given operating condition, while maintaining constant total fuel flow in each combustor 18, to alter the combustion dynamics amplitudes and/or frequencies and/or to alter the emissions generated by the combustion system.
A plurality of vanes 116 extend radially outwardly from the center body 102. In particular embodiments, the fuel nozzle assembly 100 includes an outer shroud 118 that circumferentially surrounds at least a portion of the center body 102. The outer shroud 118 is radially spaced from the center body 102 so as to define a premix flow passage 120 is therebetween. The plurality of vanes 116 extend from the center body 102 within the premix flow passage 120 and may be connected to the outer shroud 118.
One or more vanes 116 of the plurality of vanes 116 may be contoured or angled with respect to a longitudinal centerline or axis 122 of the center body 102 so as to impart angular or circumferential swirl to the compressed air 28 and/or to fuel 30 that is injected into the premix flow passage 120 from the internal fuel passage 106 via at least one fuel port 124 defined by or within one or more of the vanes 116 and which is in fluid communication with the internal fuel passage 106 during operation of the combustor 18. One or more of the vanes 116 may include a plurality of fuel ports 124 in fluid communication with the internal fuel passage 106. The fuel port(s) 124 may have any shape and may be sized the same or have different effective flow areas.
In various embodiments, as shown in
In particular embodiments, as shown in
The baffle 126 may have any cross sectional shape. For example, as shown in
The baffle(s) 126 may have any cross sectional shape. For example, as shown in
In various embodiments, multiple fuel nozzle assemblies 100 may be incorporated into the combustion system 16 to control or negate multiple combustion tones of the combustor 18.
As shown in
In particular embodiments, the baffle 126(a) of the first fuel nozzle assembly 100(a) may be longitudinally offset a specific longitudinal distance 150 from the baffle 126(b) of the second fuel nozzle assembly 100(b), particularly where the first fuel circuit 146 and the second fuel circuit 148 are operated at different fuel flow rates such as during base load and/or during turn down operation of the combustion system 16. In other words, the baffle 126(a) of the first fuel nozzle assembly 100(a) may be positioned at a first longitudinal distance D1 from the inlet 112(a) of the internal fuel passage 106(a) of the first fuel nozzle assembly 100(a), and the at least one baffle of 126(b) the second fuel nozzle assembly 100(b) is positioned within the internal fuel passage 106(b) of the second fuel nozzle assembly 100(b) at a second longitudinal distance D2 from the inlet 112(b) of the internal fuel passage 106(b) of the second fuel nozzle assembly 100(b). The first longitudinal distance D1 may be greater than or less than the second longitudinal distance D2.
In particular embodiments, the combustion system 16 includes at least one flow restrictor or orifice 152 disposed within or upstream from the first fuel circuit 146 and/or at least one flow restrictor or orifice 154 disposed within or upstream from the second fuel circuit 148. The at least one flow restrictor 152 may be positioned upstream from the inlet 112(a) to the internal fuel passage 106(a) of the first fuel nozzle assembly 100(a). In addition or in the alternative, the at least one flow restrictor 154 may be positioned upstream from the inlet 112(b) to the internal fuel passage 106(b) of the second fuel nozzle assembly 100(b).
The size and/or shape of the baffle(s) 126(a), 126(b) and/or longitudinal position within the center body 102(a). 102(b) may be determined based at least in part on the diameter or flow area of the fuel port(s) 124(a), 124(b), the diameter or flow area of the flow restrictors 152, 154, and/or one or more combustion tones or frequencies generated by the combustion system during particular operating modes such as during turn down or full speed operation, or based at least in part on particular operating parameters such as fuel type.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
Claims
1. A fuel nozzle assembly, comprising:
- a center body comprising an outer sleeve and an internal fuel passage defined within the outer sleeve, the internal fuel passage defining a fuel flow path within the center body, wherein the internal fuel passage includes an inlet defined at an upstream end of the center body, wherein the inlet is formed to receive fuel from a fuel supply;
- a plurality of vanes that extend radially outwardly from the outer sleeve, at least one of the vanes including at least one fuel port in fluid communication with the internal fuel passage; and
- at least one baffle extending radially into the internal fuel passage downstream from the inlet and upstream from the at least one fuel port, wherein the at least one baffle reduces fuel flow area within the internal fuel passage.
2. The fuel nozzle assembly as claimed in claim 1, wherein the at least one baffle extends radially inwardly from the outer sleeve into the fuel flow path.
3. The fuel nozzle assembly as claimed in claim 1, wherein the at least one baffle extends circumferentially about an inner surface of the outer sleeve with respect to a longitudinal axis of the center body.
4. The fuel nozzle assembly as claimed in claim 1, wherein a radially inner portion of the at least one baffle is at least partially triangular, arcuate or wedge shaped.
5. The fuel nozzle assembly as claimed in claim 1, wherein the at least one baffle is disposed proximate to the fuel port and distal from the inlet with respect to a longitudinal axis of the center body.
6. The fuel nozzle assembly as claimed in claim 1, where the at least one baffle is disposed proximate to the inlet and distal from the fuel port with respect to a longitudinal axis of the center body.
7. The fuel nozzle assembly as claimed in claim 1, wherein the at least one baffle comprises a plurality of baffles extending radially into the internal fuel passage downstream from the inlet and upstream from the at least one fuel port, wherein the plurality of baffles are longitudinally spaced apart with respect to a longitudinal axis of the center body.
8. The fuel nozzle assembly as claimed in claim 1, further comprising an outer shroud that circumferentially surrounds at least a portion of the center body, wherein the plurality of vanes extend from the center body and are connected to the outer shroud.
9. The fuel nozzle assembly as claimed in claim 1, further comprising a flow restrictor disposed upstream from the inlet to the internal fuel passage.
10. A combustion system, comprising:
- an end cover coupled to an outer casing and in fluid communication with a fuel supply;
- a plurality of fuel nozzle assemblies spaced radially and circumferentially across an inner surface of the end cover, wherein the plurality of fuel nozzle assemblies includes a first fuel nozzle assembly in fluid communication with a first fuel circuit and a second fuel nozzle assembly in fluid communication with a second fuel circuit, wherein the first fuel nozzle assembly comprises: a center body comprising an outer sleeve and an internal fuel passage defined within the outer sleeve, the internal fuel passage defining a fuel flow path within the center body, wherein the internal fuel passage includes an inlet defined at an upstream end of the center body and in fluid communication with the first fuel circuit; a plurality of vanes that extend radially outwardly from the outer sleeve, at least one of the vanes including at least one fuel port in fluid communication with the internal fuel passage; and at least one baffle extending radially into the internal fuel passage downstream from the inlet and upstream from the at least one fuel port, wherein the at least one baffle reduces fuel flow area within the fuel flow path.
11. The combustion system as claimed in claim 10, wherein the at least one baffle extends radially inwardly from the outer sleeve into the fuel flow path.
12. The combustion system as claimed in claim 10, wherein the at least one baffle extends circumferentially about an inner surface of the outer sleeve with respect to a longitudinal axis of the center body.
13. The combustion system as claimed in claim 10, wherein the at least one baffle is disposed proximate to the fuel port and distal from the inlet with respect to a longitudinal axis of the center body.
14. The combustion system as claimed in claim 10, the at least one baffle is disposed proximate to the inlet and distal from the fuel port with respect to a longitudinal axis of the center body.
15. The combustion system as claimed in claim 10, wherein the at least one baffle comprises a plurality of baffles extending radially into the internal fuel passage downstream from the inlet and upstream from the at least one fuel port, wherein the plurality of baffles are longitudinally spaced apart with respect to a longitudinal axis of the center body.
16. The combustion system as claimed in claim 10, further comprising a flow restrictor disposed within the first fuel circuit upstream from the inlet to the internal fuel passage.
17. The combustion system as claimed in claim 10, wherein the second fuel nozzle assembly comprises:
- a center body comprising an outer sleeve and an internal fuel passage defined within the outer sleeve, the internal fuel passage defining a fuel flow path within the center body, wherein the internal fuel passage includes an inlet defined at an upstream end of the center body and in fluid communication with the second fuel circuit;
- a plurality of vanes that extend radially outwardly from the outer sleeve, at least one of the vanes including at least one fuel port in fluid communication with the internal fuel passage; and
- at least one baffle extending radially into the internal fuel passage downstream from the inlet and upstream from the at least one fuel port, wherein the at least one baffle reduces fuel flow area within the fuel flow path.
18. The combustion system as claimed in claim 17, further comprising at least one flow restrictor disposed within at least one of the first fuel circuit and the second fuel circuit upstream from the corresponding inlet to the internal fuel passage of the first fuel nozzle assembly or the inlet of the second fuel nozzle assembly.
19. The combustion system as claimed in claim 17, wherein the at least one baffle of the first fuel nozzle assembly is positioned within the internal fuel passage of the first fuel nozzle assembly at a first longitudinal distance from the inlet of the internal fuel passage of the first fuel nozzle assembly, and the at least one baffle of the second fuel nozzle assembly is positioned within the internal fuel passage of the second fuel nozzle assembly at a second longitudinal distance from the inlet of the internal fuel passage of the second fuel nozzle assembly.
20. The combustion system as claimed in claim 19, wherein the first longitudinal distance is greater than or less than the second longitudinal distance.
Type: Application
Filed: Jan 11, 2017
Publication Date: Dec 20, 2018
Inventors: Rahul Ravindra KULKARNI (Bangalore), Madanmohan MANOHARAN (Bangalore)
Application Number: 16/062,066