COMBUSTOR HEAD END ASSEMBLY WITH DUAL PRESSURE PREMIXING NOZZLE - Patent application

Abstract

To provide a head end assembly for a combustor of a gas turbine system, which includes fuel nozzles that mix a fuel with air of two different pressures.SOLUTION: A combustor may include a combustor liner and a flow sleeve. A high-pressure air cools an outer surface of the combustor liner via openings in the flow sleeve, creating a lower-pressure air in an annulus between the combustor liner and the flow sleeve. A first fuel nozzle is positioned at a primary combustion zone, and a second fuel nozzle is positioned at a secondary combustion zone of the liner. The fuel nozzles produce a premixture of high-pressure air and a fuel, and produce a mixture of the premixture and the lower-pressure air, prior to introducing the mixture to a respective primary or secondary combustion zone of the combustor. The combustor provides improved fuel premixing, is fuel-flexible, and reduces pressure drop requirements. The combustor is usable in a can, annular or segmented annular combustor assembly.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] Government funding statement This application was made with government support under Contract No. DE-FE0023965 awarded by the U.S. Department of Energy. The U.S. Government has certain rights in this invention.

[0002] The present disclosure relates generally to gas turbine systems, and more particularly to a head-end assembly for a combustor of a gas turbine (GT) system including a fuel nozzle that mixes fuel with air at two different pressures. The GT system may include a two-stage combustion section. In one embodiment, a dual-pressure premix nozzle assembly may introduce a fuel / air mixture as part of a primary header combustion zone and as part of a secondary axially staged fuel combustion zone. [Background technology]

[0003] Gas turbine (GT) systems are used to generate power in a wide variety of applications. In the operation of a GT system, air flows through a compressor, and the compressed air is supplied to a combustion section. Specifically, the compressed air is supplied to multiple combustors, each having multiple fuel nozzles, which use the air in a combustion process with fuel to generate a combustion gas stream. The compressor includes multiple inlet guide vanes (IGVs), the angle of which can be controlled to control the airflow to the combustion section. The combustion section is in flow communication with a turbine section, where the kinetic and thermal energy of the combustion gas stream is converted to mechanical rotational energy. The turbine section includes a turbine rotatably coupled to and driving a rotor. The compressor may also be rotatably coupled to the rotor. The rotor may drive a load, such as an electrical generator.

[0004] The combustion section includes one or more combustors, such as multiple circumferentially spaced combustor “cans,” a conventional annular combustor, or a segmented annular combustor, that can be used to control the load of the GT system. Advances in can-type annular combustors have led to the use of two axially separated combustion zones. A header (or head-end) combustion zone may be positioned at the upstream end of each combustor’s combustion region. The header combustion zone includes multiple fuel nozzles that introduce fuel for combustion. Advanced gas turbine systems also include a second combustion zone, which may be referred to as an axial fuel staging (AFS) combustion zone, downstream from the header combustion zone within each can-type annular combustor’s combustion region. The AFS combustion zone includes multiple fuel nozzles or injectors that introduce fuel diverted (split) from the header combustion zone for combustion in the AFS combustion zone. The AFS combustion zone increases efficiency and assists in compliance with emission regulations for GT systems by ensuring high combustion efficiency, which reduces harmful emissions in the GT system’s exhaust.

[0005] One of the challenges of advanced gas turbine systems operating at very high temperatures is achieving adequate cooling of the combustion materials while simultaneously achieving low emissions. High-temperature operation requires premixing of fuel and air to meet emissions targets. To achieve target emissions, combustion residence time is ideally minimized by reducing the size of the combustion zone. In contrast, enhancing the premixing process typically involves adding mixing length to the combustor.

[0006] In some situations, it may be desirable to burn a liquid fuel instead of, or in addition to, a gaseous fuel. The introduction of the liquid fuel requires care to prevent coking of the liquid fuel nozzles and to ensure that the liquid fuel does not wet the adjacent walls, which can contribute to coking along the walls. Such wall coking can lead to undesirable temperature increases in the combustor liner, which may shorten the useful life of the liner. Summary of the Invention

[0007] A first aspect of the present disclosure provides a combustor for a gas turbine (GT) system, the combustor comprising: a combustor liner defining a combustion region including a primary combustion zone and a secondary combustion zone downstream from the primary combustion zone; a flow sleeve surrounding at least a portion of the combustor liner, the flow sleeve including a plurality of cooling openings therein that direct a first flow of air from a first air source at a first pressure to cool an outer surface of the combustor liner and generate a second flow of air at a second pressure lower than the first pressure within an annulus between the combustor liner and the flow sleeve; a first fuel nozzle positioned in the primary combustion zone; a second fuel nozzle positioned in the secondary combustion zone; and a fuel source configured to deliver a first fuel to each of the first and second fuel nozzles, wherein the first and second fuel nozzles generate a premixture of the first air flow and the first fuel and introduce the mixture of the premixture and the second air flow into the respective primary or secondary combustion zone.

[0008] A second aspect of the present disclosure provides a head-end assembly for a combustor of a gas turbine (GT) system, the head-end assembly comprising: a first wall defining a first plenum in fluid communication with a source of first air at a first pressure; and a plurality of fuel nozzles extending through the first plenum, each fuel nozzle having an inlet on a first side of the first plenum that opens to a source of second air at a second pressure; a first annular wall defining the first passageway, an outlet opening to the region, and a first passageway extending between the inlet and the outlet, wherein the first pressure is greater than the second pressure; a second plenum in fluid communication with the fuel source, the second plenum being at least partially within the first plenum; and a mixing conduit extending through the second plenum and fluidly connecting the first plenum and the first passageway, the mixing conduit defining at least one injection hole in fluid communication with the second plenum.

[0009] The exemplary aspects of the present disclosure are designed to solve the problems described herein and / or other problems not discussed.

[0010] These and other features of the present disclosure will be more readily understood from the following detailed description of the various aspects of the disclosure, taken in conjunction with the accompanying drawings which illustrate various embodiments of the present disclosure. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a partial cross-sectional side view of a gas turbine (GT) system according to one embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional side view of a can-annular combustor for the combustion section usable in the GT system of FIG. 1. [Figure 3] FIG. 2 is a cross-sectional side view of another can-type annular combustor for the combustion section usable in the GT system of FIG. 1. [Figure 4] FIG. 2 illustrates a cross-sectional upstream view of a combustor head-end assembly for mixing two compressed air streams and a fuel stream according to one embodiment of the present disclosure. [Figure 5] 5 is a cross-sectional view of a combustor head-end assembly taken along view line 5-5 of FIG. 4 according to one embodiment of the present disclosure. [Figure 6] 6 is a cross-sectional view of a combustor head-end assembly taken along view line 6-6 of FIG. 4 according to one embodiment of the present disclosure. [Figure 7] FIG. 6 is an enlarged cross-sectional schematic view of a first fuel nozzle that mixes two compressed air streams and a fuel stream and that may be used in the combustor head-end assembly shown in FIG. 5 according to one embodiment of the present disclosure. [Figure 8] FIG. 4 is an enlarged cross-sectional schematic view of a first fuel nozzle for use in a combustor head-end assembly according to an alternative embodiment of the present disclosure. [Figure 9] FIG. 4 is an end view of a combustor head-end assembly according to another embodiment of the present disclosure. [Figure 10] FIG. 4 is an end view of a combustor head-end assembly according to yet another embodiment of the present disclosure. [Figure 11] 1 is an upstream view of an exemplary segmented annular combustor in which the combustor head-end assemblies described herein may be used. [Figure 12]FIG. 12 is a side exploded perspective view of an integral combustor nozzle (ICN) used in the segmented annular combustor of FIG. 11 . [Figure 13] 12 is a partial cross-sectional view of a portion of a head end assembly for use with an ICN used in the segmented annular combustor of FIG. 11. FIG. [Figure 14] FIG. 2 is a schematic cross-sectional view of a second fuel nozzle that may be used in a secondary combustion zone according to one embodiment of the present disclosure for mixing two pressurized air streams and a fuel stream. [Figure 15] 15 is an enlarged schematic side cross-sectional view of a portion of a can-annular combustor similar to FIG. 2 including the second fuel nozzle of FIG. 14. DETAILED DESCRIPTION OF THE INVENTION

[0012] It should be noted that the drawings of the present disclosure are not necessarily to scale. The drawings are intended to depict only typical aspects of the present disclosure and therefore should not be considered limiting of the scope of the present disclosure. In the drawings, like numbers represent like elements between the drawings.

[0013] As an initial matter, in order to clearly explain the present disclosure, it is necessary to select specific terminology to reference and describe the relevant mechanical components within a gas turbine (GT) system. Wherever possible, common industry terminology is used and utilized consistent with its accepted meaning. Unless otherwise noted, such terminology should be given a broad interpretation consistent with the context of this application and the scope of the appended claims. Those skilled in the art will recognize that in many cases, a particular component may be referred to using several different or overlapping terms. What may be described herein as a single component may include and be referred to in other contexts as consisting of multiple components. Alternatively, what may be described herein as comprising multiple components may be referred to elsewhere as a single component.

[0014] Additionally, several descriptive terms may be used regularly herein, and it will prove useful to define these terms at the beginning of this section. These terms and their definitions, unless otherwise stated, are as follows: As used herein, "downstream" and "upstream" are terms that indicate a direction relative to the flow of a working fluid through a turbine engine or a fluid, such as, for example, the flow of air through a combustor or a dual pressure fuel nozzle of the present invention. The term "downstream" corresponds to the direction of fluid flow, and the term "upstream" refers to the direction opposite to the flow (i.e., the direction from which the fluid is coming). The terms "forward" and "aft," unless otherwise specified, refer to directions, with "forward" referring to the front or compressor end of the engine and "aft" referring to the rear or turbine end of the engine.

[0015] Additionally, it is often desired to describe components at different radial locations relative to the central axis. The term "radial" refers to movement or position perpendicular to the axis. In such cases, if a first component is located closer to the axis than a second component, the first component may be referred to herein as being "radially inward" or "inward" of the second component. Conversely, if a first component is located farther from the axis than the second component, the first component may be referred to herein as being "radially outward" or "outward" of the second component. The term "axial" refers to movement or position parallel to the axis. Finally, the term "circumferential" refers to movement or position around the axis. It will be understood that such terms may be applied relative to the central axis of the turbine.

[0016] When an element or layer is referred to as "on," "engaged," "connected," or "coupled" to another element or layer, it can be directly on, engaged, connected, or coupled to the other element or layer, or intervening elements or layers may be present. Conversely, when an element is referred to as "directly on," "directly engaged," "directly connected," or "directly coupled" to another element or layer, there may not be intervening elements or layers. Other terms used to describe relationships between elements should be interpreted similarly (e.g., "between" versus "directly between," "adjacent to" versus "directly adjacent to," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0017] As indicated above, the present disclosure provides embodiments of a combustor head-end assembly and a combustor. The combustor may include a combustor liner defining a combustion region including a primary head-end combustion zone and a secondary axial fuel staging (AFS) combustion zone downstream from the primary combustion zone. A flow sleeve surrounds at least a portion of the combustor liner. The flow sleeve includes a plurality of cooling openings therein that direct a first airflow from a first air source at high pressure (e.g., compressor discharge pressure) to cool an outer surface of the combustor liner and generate a second airflow at a pressure lower than the high pressure within an annulus between the combustor liner and the flow sleeve.

[0018] A first fuel nozzle is positioned in the primary combustion zone, and a second fuel nozzle is positioned in the secondary combustion zone. A fuel source is configured to deliver a first fuel to each of the first and second fuel nozzles. In various embodiments, the fuel source can deliver gas and / or liquid fuel to the respective nozzles. Both the first and second fuel nozzles are configured to generate a premixture of high-pressure airflow and fuel using airflows at two different pressures, and then generate a mixture of the premixture and low-pressure airflow before introducing the mixture into the combustion zone. The dual-pressure premix nozzle can be used only as part of a combustor head-end assembly in the primary (head-end) combustion zone, or as part of the combustor head-end assembly in the primary combustion zone and as a fuel nozzle in the secondary (AFS) combustion zone.

[0019] The use of the dual-pressure premix nozzle of the present invention in both combustion zones improves fuel premixing in both zones. The use of the combustor head-end assembly of the present invention reduces premix residence time, which is advantageous when the fuel contains a high concentration of highly reactive fuels, such as hydrogen. In addition, the fuel nozzle is fuel-flexible (e.g., gas and / or liquid). High-velocity fuel nozzles enhance the performance of premix fuel nozzles by lowering inlet pressure and increasing overall turbulence within the fuel nozzle, thereby reducing emissions and reducing pressure drop requirements. The fuel nozzle outlet can be angled to direct the fuel as needed, further improving fuel / air (F / A) mixing. The combustor head-end assembly can be used with can-annular combustors, conventional annular combustors, or segmented annular combustors. In the latter case, the combustion annulus may be separated into individual combustion zones by a circumferential array of integral combustor nozzles (ICNs), as described, for example, in U.S. Patent Application No. 15 / 464,394, published as U.S. Patent Application Publication No. 2017-0276369(A1).

[0020] FIG. 1 illustrates a partial cross-sectional view of an exemplary GT system 100 in which the teachings of the present disclosure may be employed. In FIG. 1 , the GT system 100 includes an intake section 102 and a compressor 104 downstream from the intake section 102. The compressor 104 supplies air to a combustion section 106 coupled to a turbine section 120. The compressor 104 may include one or more stages of inlet guide vanes (IGVs) 123. As understood in the art, the angle of the stages of the IGVs 123 may be controlled to control the airflow rate to the combustion section 106 and, therefore, the combustion temperature of the section 106, among other things. The combustion section 106 includes multiple combustors 126, i.e., can-annular combustors, as illustrated, that combust fuel and air to form a combustion product stream for driving the turbine section 120. Exhaust from the turbine section 120 exits via an exhaust section 122.

[0021] A turbine section 120 through a common shaft or rotor 121 drives the compressor 104 and a load 124. The load 124 can be either a generator or a mechanical drive application and can be located in front of the intake section 102 (as shown) or aft of the exhaust section 122. Examples of such mechanical drive applications include compressors for use in oil fields and / or refrigeration. In the case of oil field applications, the application can be gas reinjection service. In the case of refrigeration applications, the application can be a liquid natural gas (LNG) plant. Yet another load 124 can be a propeller such as may be found on turbojet, turbofan, and turboprop engines.

[0022] Referring to the exemplary embodiment of FIG. 1 , the combustion section 106 may include a circular array of multiple circumferentially spaced can-type annular combustors 126. FIG. 2 illustrates a cross-sectional view of the exemplary can-type annular combustor 126. For purposes of this description, only one combustor 126 is shown, but it is understood that all of the other combustors 126 disposed around the combustion section 106 are substantially identical to the illustrated combustor 126. Each combustor 126 includes a primary combustion zone 108 and a secondary combustion zone 110 downstream from the primary combustion zone 108. While FIG. 1 illustrates multiple circumferentially spaced combustors 126 and FIG. 2 illustrates a cross-sectional side view of the can-type annular combustor 126, it is contemplated that the present disclosure may be used in conjunction with other combustor systems, including, but not limited to, annular combustors and segmented annular combustors with ICNs. Where applicable, application of the teachings of the present disclosure to these other types of combustors is provided herein.

[0023] Regardless of the type of combustor system, the primary and secondary combustion zones 108, 110 each include one or more fuel nozzles 170, 172, respectively, in the form of a dual-pressure fuel mixing apparatus. Further details of the fuel nozzles 170, 172 are as described in co-pending U.S. patent applications Ser. Nos. 16 / 731,283 and 16 / 731,306, entitled "Fluid Mixing Apparatus Using High- and Low-Pressure Fluid Streams" (GE Docket No. 319516) and "Fluid Mixing Apparatus Using Liquid Fuel and High- and Low-Pressure Fluid Streams" (GE Docket No. 326982), respectively, filed concurrently herewith and incorporated herein by reference. A fuel / air mixture is combusted in each combustor 126 to generate a hot, energetic combustion gas stream 129, which flows through a liner 146 and its transition piece 128 (Figure 2) to a turbine nozzle 130 (Figure 2) in the turbine section 120 (Figure 1).

[0024] Referring now to FIG. 2, a combustor 126 for the GT system 100 (FIG. 1) is illustrated schematically. The combustor 126 may include or be positioned within a casing 132, typically referred to as a combustor discharge casing (CDC) or combustor casing. The combustor 126 may include an end cover 134, a combustor head-end assembly 142, a flow sleeve 144, and a combustor liner 146 within the flow sleeve 144. The combustor liner 146 defines a combustion region 160 that includes the primary combustion zone 108 and a secondary combustion zone 110 downstream from the primary combustion zone 108. Alternatively, a transition piece 128 may define the secondary combustion zone 110. In other embodiments, the liner 146 and the transition piece 128 may be formed as a single component rather than two separate components. The flow sleeve 144 surrounds at least a portion of the combustor liner 146, forming an annular plenum 148 therebetween. Flow sleeve 144 includes a plurality of cooling openings 150 that facilitate, i.e., via, impingement cooling of an exterior surface 182 of combustor liner 146. (The downstream portion of flow sleeve 147 may be referred to as a transition piece impingement sleeve.)

[0025] The compressor 104 (FIG. 1), represented by a series of vanes and blades 152 and a diffuser 154 in FIG. 1, provides high-pressure air 180 to a high-pressure air plenum 162 defined between the casing 132 and the flow sleeve 144, thus forming a high-pressure (HP) air source 164. That is, the high-pressure air source 164 includes the air plenum 162 defined between the casing 132, i.e., the compressor discharge housing, and at least a portion of the flow sleeve 144. The pressure P1 of the high-pressure air 180 may depend on numerous factors, such as, but not limited to, the size or operating state of the compressor 104, the location of the IGV 123 (FIG. 1), environmental conditions, and / or the operational requirements of the GT system 100 (FIG. 1).

[0026] The cooling openings 150 within the flow sleeve 144 direct the flow of the high-pressure air 180 with a first high pressure P1 from the high-pressure air source 164, i.e., cool the outer surface 182 of the combustor liner 146 or its transition piece 128 via impingement cooling. Any number of cooling openings 150 may be provided. As a result of the flow of the high-pressure air 180 entering the cooling openings 150, a flow of low-pressure air 186 is generated at a second pressure P2 that is lower than the first pressure P1, i.e., P2 < P1. The second air flow 186 flows upstream within the annulus 148 between the combustor liner 146 and the flow sleeve 144, such that the annulus 148 provides a low-pressure (LP) air source. The pressure P2 of the low-pressure air 186 may depend on a number of factors including, but not limited to, the size or operating conditions of the compressor 104, the position of the IGV 123 (FIG. 1), environmental conditions, the operating requirements of the GT system 100 (FIG. 1), the number and size of the cooling openings 150, the backpressure along the annulus 148, the temperature of the air, and / or the temperature of the combustion liner 146 and / or its transition piece 128.

[0027] In one embodiment shown in FIG. 2, the combustor 126 includes a first fuel nozzle 170 positioned in the combustor head end assembly 142 at the primary combustion zone 108 (immediately upstream thereof) and a second fuel nozzle 172 positioned through the combustor liner 146 or its transition piece 128 at the secondary combustion zone 110, defining an axial staged fuel delivery system. Each of the fuel nozzles 170, 172 may include a two-pressure premixing device as described herein. Any number of fuel nozzles 170 may be used in the primary combustion zone 108 within the combustor head end assembly 142 (hereinafter simply "head end assembly 142"), and any number of circumferentially arranged fuel nozzles 172 may be used in the secondary combustion zone 110. In another embodiment shown in FIG. 3, the combustor 126 may include only the first fuel nozzle 170 positioned in the primary combustion zone 108 within the head end assembly 142, i.e., no AFS fuel nozzle is provided.

[0028] The combustor 126 may also include one or more fuel sources 190 configured to deliver fuel 192, e.g., gas fuel (such as natural gas, hydrogen, etc.), and / or fuel 194, e.g., liquid fuel (such as distillate or other petroleum products), to each of the first and / or second fuel nozzles 170, 172. The fuel source 190 may include any now known or later developed fuel source, including, for example, a fuel reservoir, a control system, piping, valves, meters, sensors, liquid fuel atomizers, etc.

[0029] As will be described in more detail, the first and second fuel nozzles 170, 172 generate a premix of high-pressure air 180 and fuel (gas fuel 192 and / or liquid fuel 194), and after generating a mixture of the premix (i.e., high-pressure air 180 and fuel) and low-pressure air 186, introduce the mixture into the respective primary combustion zone 108 or secondary combustion zone 110.

[0030] With respect to the first fuel nozzles 170 and head end assembly 142 for the combustor 126 ( FIGS. 2 and 3 ) of the GT system 100 ( FIG. 1 ), embodiments of the present disclosure may provide a head end arrangement 204 that includes the head end assembly 142 and a plurality of first fuel nozzles 170 installed throughout the head end assembly 142. As best shown in FIGS. 2 and 3 , the head end assembly 142 may be attached to the combustor liner 146 in any now known or later developed manner, such as by fasteners, welding, molding, etc.

[0031] Figure 4 illustrates a cross-sectional upstream view of a head-end assembly 142 for mixing two air and fuel streams at different pressures for combustion in a combustion zone 160 (Figure 2) according to one embodiment of the present disclosure (see view 4-4 in Figure 2). Figure 5 illustrates a cross-sectional view of the head-end assembly 142 along view 5-5 in Figure 4, Figure 6 illustrates a cross-sectional view of the head-end assembly 142 along view 6-6 in Figure 4, and Figure 7 illustrates an enlarged schematic cross-sectional view of a first fuel nozzle 170 for the head-end assembly 142 shown in Figure 5.

[0032] The head-end assembly 142 may include a first wall 200 that defines a first plenum 202 in fluid communication with the high-pressure air source 164. In one embodiment, the first wall 200 may form a generally box-shaped structure ( FIGS. 5-6 ) configured to mount to the upstream end of the combustor liner 146. The first wall 200 may have a first side 212 that defines an upstream face, a spaced-apart, opposing second side 214 that defines a downstream face, and an outer annular wall 210 extending between and coupled to the first side 212 and the second side 214 to form the first plenum 202 therein. The head-end assembly 142, and in particular the second side 214 of the first wall 200, form an upper boundary of the combustor liner 146 and the combustion region 160.

[0033] 2 and 3, head-end assembly 142 is circular because the example is for can-annular combustor 126 (FIG. 2), which typically has a circular shape (see, e.g., circumferentially spaced can-annular combustor in FIG. 1). That is, first side 212 and second side 214 are circular. As will be described in more detail, head-end assembly 142 can have a variety of different shapes depending on the type of combustor used.

[0034] The head end assembly 142 also includes a plurality of fuel nozzles 170, as described in more detail herein, that extend through the first plenum 202. Any number of fuel nozzles 170 (e.g., 12) may be used in a circular assembly, as shown in the example assembly of FIG.

[0035] As shown in FIGS. 4 and 5 , a connector passage 206 may traverse the annulus 148 to fluidly couple the first plenum 202 and the high-pressure air source 164 and deliver high-pressure air 180 to the first plenum 202. The connector passage 206 may be located at any circumferential location on the head-end assembly 142, and more than one connector passage 206 may be used. The connector passage 206 may have any size and shape and location to allow a sufficient amount of high-pressure air 180 to supply the first nozzle 170 in the head-end assembly 142. In FIG. 5 , the low-pressure air 186 passes around the connector passage 206 (backward as shown), while FIG. 6 shows that if the connector passage 206 is not provided, the annulus 148 would continue uninterrupted.

[0036] 2 and 3, the low-pressure air source 188 may also include a head-end plenum 208. The head-end plenum 208 may be defined in a number of variations. In FIG. 2, the head-end plenum 208 is defined by, on opposite sides, a first (upstream) side 212 of the first wall 200 (defining the first plenum 202) and the end cover 134. Additionally, in FIG. 2, the head-end plenum 208 is circumferentially bounded by the flow sleeve 144 (extending into the compressor discharge casing 132). An optional inlet flow conditioner (not shown) may be provided extending upstream of the head-end assembly 142 in a position aligned with the combustor liner 146. 3 , the head-end plenum 208 may be defined by the first side 212 of the first wall 200 (first plenum 202) of the head-end assembly 142 with only the flow sleeve 144. Here, the flow sleeve 144 closes around the head-end assembly 142. In either case, the head-end plenum 208 receives the low-pressure air 186 from the annulus 148. Each first nozzle 170 includes an inlet 222 in fluid communication with the head-end plenum 208 such that each first nozzle 170 receives the flow of low-pressure air 186 from the shared head-end plenum 208.

[0037] 5-7 collectively, the fuel nozzles 170 in the head-end assembly 142 may include substantially identical structures. The fuel nozzles 170 may include an inlet 222 at a first (upstream) side 212 of the first plenum 202, an outlet 224 at a second (downstream) side 214 of the first plenum 202 that opens to the combustion zone 160 of the combustor, and a first annular wall 220 that defines a first main passage 226 extending between the inlet 222 and the outlet 224. The first annular wall 220 may be cylindrical or may have a radial cross-section that defines a non-circular shape, such as an elliptical shape, a racetrack shape, or a polygonal shape (e.g., a rectangular shape). The inlet 222 is open to the low-pressure air source 188, allowing the low-pressure air 186 to enter the inlet 222.

[0038] The fuel nozzle 170 may also include a second annular wall 230 circumscribing the first annular wall 220 to define a second plenum 232 in fluid communication with the fuel source 190. As best shown in FIG. 7 , the second plenum 232 is at least partially within the first plenum 202. The head-end assembly 142 may include a fuel manifold 236 that fluidly couples each second plenum 232 within the first plenum 202 to the fuel source 190, which is fluidly coupled to the fuel manifold 236. The fuel manifold 236 may be formed by any form of conduit 238 that fluidly couples the second plenums 232. The conduit 238 may be formed in any manner, for example, by a pipe extending between the plenums 232 within the first plenum 202. If the second plenum 232 is used to deliver fuel, the fuel 192 may include a gas fuel such as natural gas, propane, or the like.

[0039] The fuel nozzle 170 also includes a mixing conduit 240 that extends through the second plenum 232 and fluidly connects the first plenum 202 and the main passage 226. The mixing conduit 240 defines at least one injection hole 242 that is in fluid communication with the second plenum 232. Each of the one or more mixing conduits 240 that extend through the second plenum 232 has an inlet 244 that is fluidly connected to the first plenum 202 and an outlet 246 that is fluidly connected to the main passage 226. That is, each first nozzle 170 shares a common first plenum 202 in the head-end assembly 142. One or more injection holes 242 are defined through each mixing conduit 240 and are in fluid communication with the plenum 232. The fuel 192 flows through the one or more injection holes 242 into a passage 250 defined by each mixing conduit 240. In one embodiment, the mixing conduit 240 is aligned with the axial centerline C of the fuel nozzle 170. L Preferably, the mixing conduits 240 are oriented at an angle to direct flow through the conduit in a downstream direction (i.e., toward the outlet 224). The mixing conduits 240 (individually) are shorter and have a smaller diameter than the first annular wall 220.

[0040] During operation, for each first nozzle 170, high-pressure air 180 from high-pressure air source 164 flows through first plenum 202 (via mixing conduit 240) into main passage 226, and fuel 192 flows through one or more injection holes 242 into main passage 226. The pressure of first high-pressure air 180 rapidly carries fuel 192 into main passage 226 defined by first annular wall 220, creating a premixture. High-pressure air 180 also draws low-pressure air 186 into inlet 222 of main passage 226. Within main passage 226, the premixture of high-pressure air 180 and fuel 192 mixes with low-pressure air 186 to generate a mixed fuel / air mixture 260 that exits outlet 224 of main passage 226 into combustion zone 160 of combustor 126 (FIG. 2). As a result, a combustion reaction occurs within the primary combustion zone 108 of the combustor liner 146, producing a combustion gas stream 129 (FIG. 2) that releases heat for the purpose of driving the turbine section 120 (FIG. 1).

[0041] The head-end assembly 142 can be arranged in a number of different ways to customize it for a particular combustor and / or to accommodate a wide variety of combustor types. In one embodiment shown in FIG. 8 , at least one of the multiple fuel nozzles 170 can have an outlet 224 positioned at a non-perpendicular angle α relative to the second side 214 of the first plenum 202 in the head-end assembly 142, i.e., combustion region 160. In this manner, the fuel / air mixture 260 can be directed into the combustion region 160 at the angle α, creating a swirl flow. When multiple nozzles 170 are so arranged, fuel and air mixing can be further enhanced, for example, by pointing the nozzles 170 toward one another. While the main passage 226 is shown angled along its entire length relative to the second side 214, it may be angled only at or near the outlet 224. Any number of nozzles 170 can be angled in this manner to direct the fuel / air mixture 260 as desired. The angle α need not be the same among all of the first nozzles 170 provided.

[0042] In alternative embodiments, the fuel nozzles 170 may be arranged in a number of different patterns within the head-end assembly 142. In one embodiment, shown in FIG. 4, the fuel nozzles 170 are arranged in an annular, or ring-like, configuration within the head-end assembly 142 facing the combustion region 160 (FIG. 2). In another example, shown in FIG. 9, the fuel nozzles 170 may be arranged in a pair of concentric rings 262, 264 within the head-end assembly 142 as they face the combustion region 160 (FIG. 2). In FIG. 10, the fuel nozzles 170 are arranged in a more linear configuration within the head-end assembly 142. Virtually any arrangement is possible, allowing for a high level of customization of the introduction of the fuel / air mixture into the combustion region 160.

[0043] FIG. 11 illustrates an upstream (i.e., aft-to-forward) view of the combustion section 106 ( FIG. 1 ) according to an alternative embodiment of the present disclosure. As shown in FIG. 11 , the combustion section 106 may be an annular combustion system, more specifically, a segmented annular combustor 292 in which an array of integrated combustor nozzles 290 are arranged circumferentially about an axial centerline 301 of the GT system 100 ( FIG. 1 ). The axial centerline 301 may be coincident with the shaft 121 ( FIG. 1 ). The segmented annular combustor 292 may be at least partially surrounded by an outer casing 132, sometimes referred to as a compressor discharge casing. The casing 132, which receives high-pressure air 180 from the compressor 104 ( FIG. 1 ), may at least partially surround various components of the segmented annular combustor 292 and at least partially define a high-pressure air source 364 located within the center of the combustor. The high-pressure air 180 is used for combustion and for cooling the combustor hardware, as described above.

[0044] The segmented annular combustor 292 includes a circumferential array of integral combustor nozzles 290, one of which is shown in a side exploded perspective view in FIG. 12. As shown in FIG. 12, each integral combustor nozzle (ICN) 290 includes an inner liner segment 302, an outer liner segment 304 radially separated from the inner liner segment 302, and a hollow or semi-hollow fuel injection panel 310 extending radially between the inner liner segment 302 and the outer liner segment 304, thus generally defining an "I" shaped assembly. Collectively, the inner liner segment 302 and the outer liner segment 304 form a combustion liner 346 ( FIG. 11 ). The combustion liner 346 defines the combustion region 160, which includes the primary combustion zone 108 and the secondary combustion zone 110 downstream from the primary combustion zone 108. Fuel injection panels 310 separate the combustion region 160 into an annular array of fluidly separated combustion areas (one area is identified in FIG. 12 by primary combustion zone 108 and secondary combustion zone 110). In this configuration, high pressure air 180 passes through cooling openings 350, thereby losing pressure and becoming low pressure air 186.

[0045] At the upstream end of the segmented annular combustor 292, a segmented combustor head-end assembly 342 (hereinafter, "head-end assembly 342") extends circumferentially adjacent the end 306 of the fuel injection panel 310 and radially from the inner liner segment 302 beyond the outer liner segment 304. FIG. 13 shows a partial cross-sectional view of a head-end assembly 342 for use with the ICN 290. The circumferentially arranged segmented head-end assembly 342 includes one or more fuel nozzles 170 that introduce a fuel / air mixture into a circumferential array of the upstream primary combustion zone 108, as described herein with respect to FIGS. 5 and 6. Each head-end assembly 342 has a similar structure to that shown in FIGS. 5 and 6, except that the first wall 200 (e.g., first annular wall 210 and side surfaces 212, 214 (FIGS. 5-6)) may have wall segments with an arcuate profile when viewed forward from an aft position, as shown in FIG. 11. 11 and 12 , it should be noted that each head end assembly 342 can overlap an end 306 of a fuel injector panel 310. For example, end 306 of fuel injector panel 310 can mate with side 314 of head end assembly 342 that lacks nozzles 170 and faces combustion zone 160, i.e., area 307 within the interface plate. In this manner, end 306 of fuel injector panel 310 does not mate with the seam between adjacent head end assemblies 342.

[0046] An inner flow sleeve 344A is positioned radially inward of the inner liner segment 302 to form an inner plenum 387, and an outer flow sleeve 344B is positioned radially outward of the outer liner segment 304 to form an outer plenum 389. Thus, the flow sleeves 344A, 344B surround at least a portion of the combustor liner 346. Cooling openings 350 are positioned in each flow sleeve 344A, 344B, making them cooling impingement sleeves. The cooling openings 350 are positioned radially inward from the inner liner segment 302 and radially outward from the outer liner segment 304. A first portion of the high-pressure air 180 from the high-pressure air source 364, defined between the casing 132 and the flow sleeve 344B and inside the flow sleeve 344A, flows through the cooling openings 350 in the flow sleeves 344A, 344B. Thus, flow sleeves 344A, 344B and cooling openings 350 channel a portion of high-pressure air 180 from high-pressure air source 364 to cool the outer surfaces of combustor liner 346, i.e., the radially inner surface of inner liner segment 302 and the radially outer surface of outer liner segment 304. Additionally, flow sleeves 344A, 344B and cooling openings 350 generate a flow of low-pressure air 186 upstream of inner and outer plenums 387, 389, forming a low-pressure air source 388 for head-end assembly 342. (Plenums 387, 389 form a circumferentially segmented annulus comparable to annulus 148 of FIGS. 2 and 3 .) As described, a second portion of high-pressure air 180 is channeled to fuel nozzles 170 within head-end assembly 342.

[0047] The head-end assembly 342 may include a first wall 300 defining a high-pressure plenum 303 (similar to the first plenum 202 in FIGS. 7 and 8 ) in fluid communication with a high-pressure air source 364. In one embodiment, the first wall 200 may form a generally box-shaped structure (similar to FIGS. 5-6 ) configured to mount to the upstream end of a combustor liner 346. The first wall 200 may have a first side 312 defining an upstream face, a spaced-apart, opposing second side 314 defining a downstream face, and an outer side 311 extending between and coupled to the first side 312 and second side 314 to form the high-pressure plenum 303 therein. The head-end assembly 142, and in particular the second side 314 of the first wall 200, form an upper boundary of the combustor liner 346 and the combustion region 160. High pressure air 180 from a high pressure air source 364 defined by the casing 132 flows through one or more connectors 206 to a high pressure air plenum 303 defined within the head end assembly 342. The sides 312, 314 are arcuate and form the arcuate high pressure air plenum 303 for use with the segmented annular combustor 292.

[0048] As shown in Figures 12 and 13, a connector passage 206 can fluidly couple the high-pressure plenum 303 and the high-pressure air source 364 across the plenums 387, 389 to deliver high-pressure air 180 to the high-pressure plenum 303. The connector passage 206 can be at any circumferential location on the head-end assembly 142, and more than one connector passage 206 can be used (two in Figure 12). The connector passage 206 can have any size and shape and location to allow a sufficient amount of high-pressure air 180 to supply the first nozzle 170 in the head-end assembly 342. In Figures 12 and 13, the low-pressure air 186 passes around the connector passage 206 (back as shown in Figure 13).

[0049] The inner and outer plenums 387, 389 direct the low-pressure air 186 to a low-pressure head-end plenum 308, where the low-pressure air 186 enters the fuel nozzles 170 in a generally axial direction. The low-pressure head-end plenum 308 includes an upstream plate 334 that cooperatively interacts with a side 312 of a wall 311 of the head-end assembly 342 (separating the low-pressure head-end plenum 308 from the high-pressure head-end plenum 303), and a wall 210 that extends axially between the upstream plate 334 and the side 314. In either case, the head-end plenum 308 receives the low-pressure air 186 from the plenums 387, 389. Each first nozzle 170 includes an inlet 322 in fluid communication with the head-end plenum 308 such that each first nozzle 170 receives the flow of low-pressure air 186 from the shared low-pressure head-end plenum 308.

[0050] The fuel nozzles 170 in the head end assembly 342 may include substantially the same structure as described with respect to Figures 5-7.

[0051] 7 and 13 , during operation, for each first nozzle 170, high-pressure air 180 from high-pressure air source 364 flows through high-pressure plenum 303 (via mixing conduit 240) into main passage 226, and fuel 192 flows through one or more injection holes 242 into main passage 226. The pressure of first high-pressure air 180 rapidly carries fuel 192 into main passage 226 defined by first annular wall 220, creating a premixture. High-pressure air 180 also draws low-pressure air 186 into inlet 222 of main passage 226. Within main passage 226, the premixture of high-pressure air 180 and fuel 192 mixes with low-pressure air 186 to generate a mixed fuel / air mixture 260 that exits outlet 224 of main passage 226 into combustion zone 160 of segmented annular combustor 292 ( FIG. 11 ). As a result, a combustion reaction occurs within the primary combustion zone 108 of the combustor liner 346, producing a combustion gas stream 329 that releases heat for the purpose of driving the turbine section 120 (FIG. 1).

[0052] As described in more detail in related U.S. patent applications Ser. Nos. 16 / 731,283 and 16 / 731,306, to achieve a greater operating range (e.g., turndown) and lower emissions, the fuel injection panel 310 includes a plurality of second nozzles 172 therein that introduce fuel into one or more secondary combustion zones 110. The combustion zones 110 are downstream of the primary combustion zone 108 formed by the injection of a fuel / air mixture delivered by the head-end assembly 342. That is, the second nozzles 172 are part of one or more integral combustor nozzles (ICNs) 290. Collectively, the segmented annular combustors 292 generate a combustion gas stream for driving the turbine section 120 (FIG. 1).

[0053] As shown in Figure 2, the can-annular combustor 126 may employ first and second nozzles 170, 172 in the primary and secondary combustion zones 108, 110, respectively. Figures 14 and 15 show cross-sectional schematic views of a second nozzle 172 that may be employed in the can-annular combustor 126 in the secondary combustion zone 110 according to an embodiment of the present disclosure. Figure 14 shows a cross-sectional schematic view of the second fuel nozzle 172, and Figure 15 shows an enlarged cross-sectional schematic side view of a portion of the can-annular combustor 126 similar to Figure 2, including the second fuel nozzle 172 of Figure 14.

[0054] In one embodiment, the second fuel nozzle 172 includes a first annular wall 420 that defines a main passage 426 that is in fluid communication with the low-pressure air source 188. The first annular wall 420 may be cylindrical or may have a radial cross-section that defines a non-circular shape, such as an elliptical shape, a racetrack shape, or a polygonal shape (e.g., a rectangular shape). The first annular wall 420 may be attached to the outer surface 182 of the combustor liner 146. As shown, the low-pressure air source 188 may include an annulus 148 between the flow sleeve 144 and the combustor liner 146. Note that in this location, the low-pressure air source 188 collects the low-pressure air 186 after impingement cooling of the outer surface 182 of the combustor liner 146 ( FIGS. 2 and 15 ), i.e., post-impingement air. The first annular wall 420 has an upstream end that defines an inlet 422 for the low pressure air 186 and a downstream end that defines an outlet 424 of the fuel nozzle. The inlet 422 may define a bellmouth shape to facilitate introduction of the low pressure air 186 into a main passage 426.

[0055] A second annular wall 430 may be disposed radially upstream of the inlet 422 of the first annular wall 420. In one embodiment shown in FIG. 14 , the second annular wall 430 may define a plenum 402 in fluid communication with the high-pressure air source 164 via one or more openings 433 in the second annular wall 430. Here, the flow of high-pressure air 180 from the high-pressure air source 164 may be directed through the one or more openings 433 in the second annular wall 430 to fill the plenum 402. In another embodiment shown in FIG. 15 , the second annular wall 430 may define the plenum 402 by being in direct fluid communication with the high-pressure air source 164, i.e., without a circumferentially extending portion in which the openings 433 ( FIG. 14 ) are provided. Here, the flow of high-pressure air 180 from the high-pressure air source 164 may be directed directly to the second annular wall 430 to fill the plenum (space) 402. As previously mentioned, high pressure air 180 has a pressure P1 from high pressure air source 164 (compressor discharge air) that is greater than a pressure P2 of low pressure air 186 (post-impingement air) from low pressure air source 188. A third annular wall 438 may be nested within plenum 402 and may be surrounded by second annular wall 430. Third annular wall 438 defines a plenum 432 in fluid communication with fuel source 190.

[0056] A mixing conduit 440 extending through the plenum 432 includes an inlet 444 in fluid communication with the plenum 402 and an outlet 446 that directs flow to the main passage 426 defined by the first annular wall 420. One or more injection holes 442 are defined through the mixing conduit 440 and are in fluid communication with the plenum 432 defined by the third annular wall 438. The fuel 192 may flow through the one or more injection holes 442 and into a passage 450 defined by the mixing conduit 440. The mixing conduit 440 is oriented to direct flow through the conduit in a downstream direction (i.e., toward the outlet 424). In this embodiment, for the second nozzle 172, the second annular wall 430, the third annular wall 438, and the mixing conduit 440 are attached to the outer surface 437 of the flow sleeve 144.

[0057] The second fuel nozzle 172 facilitates mixing of the high-pressure air 180, the low-pressure air 186 (from the annulus 148), and the fuel 192. During operation, the high-pressure air 180 from the high-pressure air source 164 flows through the plenum 402 into the passage 450, and the fuel 192 flows through one or more injection holes 442 into the passage 450, creating a premixture of the high-pressure air 180 and the fuel 192. The flow of the high-pressure air 180 rapidly carries the fuel 192 downstream into the main passage 426 defined by the first annular wall 420, where the rapid flow of the high-pressure air 180 serves to draw the low-pressure air 186 into the inlet 422 of the main passage 426. Within the main passage 426, the premix of high-pressure air 180 and fuel 192 is mixed with the low-pressure air 186 to generate a mixture, i.e., a mixed fuel / air stream 460, which exits the outlet 424 of the fuel nozzle 172 into the combustion region 160, and specifically into the secondary combustion zone 110 thereof. Because the main passage 426 of the second fuel nozzle 172 includes an outlet 424 that opens into the combustion region 160 within the combustor liner 146, the output of the second fuel nozzle 172, i.e., the mixed fuel / air stream 460, is directed substantially radially into the combustor liner 146 (and secondary combustion zone 110). As a result, a combustion reaction occurs within the secondary combustion zone 110 of the combustor liner 146, and a hot combustion gas stream 129 flows from the primary combustion zone 108, thereby powering the turbine section 120 ( FIG. 1 ) and releasing additional heat for the purpose of reducing emissions.

[0058] 15 illustrates an alternative mounting of the second fuel nozzles 172 within the can-annular combustor 126 compared to FIG. 2 . That is, the fuel nozzles 172 are located on the transition piece 128 of the combustor liner 146 of the combustor 126 rather than in a more upstream portion of the combustor liner 146. The second fuel nozzles 172 may be positioned anywhere along the circumference or length of the combustor 126 to generate the secondary combustion zone 110. Any number of second fuel nozzles 172 may be used, for example, in a circumferential array. In a similar manner as described above, the first annular wall 420 may be attached to the transition piece 128, and the second annular wall 430, the nested third annular wall 438, and the mixing conduit 440 are attached to the flow sleeve 144. High pressure air 180 flowing through a mixing conduit 440 (FIG. 14) into the main passage 426 promotes mixing of the high pressure air 180 , the low pressure air 186 (from the annulus 148 ), and the fuel 192 .

[0059] With respect to the overall operation of the can-annular combustor 126, including the first and second fuel nozzles 170, 172 (FIG. 2), it is noted that both the first and second fuel nozzles 170, 172 generate a premixture of high-pressure air 180 and fuel 192 (and / or 194) and generate a mixture of the premixture (i.e., high-pressure air 180 and fuel 192) and low-pressure air 186 before introducing the mixture into the respective primary combustion zone 108 or secondary combustion zone 110. In this regard, both the first and second fuel nozzles facilitate mixing of the high-pressure air 180, low-pressure air 186 (from the annulus 148 (FIGS. 2-3) or plenums 387, 389 (FIG. 12)), and fuel 192 before introducing the mixture into the respective primary combustion zone 108 or secondary combustion zone 110.

[0060] Operation may also vary based on the type of fuel, for example, gaseous fuel 192 and / or liquid fuel 194. As previously mentioned, when the fuel includes gaseous fuel 192, the flow of high-pressure air 180 through the mixing conduit 240, 440 entrains the flow of gaseous fuel 192 from at least one injection hole 242, 442, generating a premixture of high-pressure air 180 and gaseous fuel 192. The mixing conduit 240, 440 conveys the premix to the main passage 226, 426. Within the main passage 226, 426, the premix draws low-pressure air 186 into and out of the passage, generating a mixture of the low-pressure air 186 and a premix of high-pressure air and gaseous fuel.

[0061] In an alternative embodiment, the fuel may include liquid fuel 194. In this case, the liquid fuel 194 is delivered by a fuel source 190 to the inlets 222, 422 of the main passages 226, 426 in each nozzle 170, 172. In the second nozzle 172 (FIG. 14), the fuel source 190 may deliver the liquid fuel 194 to the opening 433 and pass through the plenum 402 before reaching the inlet 422, or the fuel source 190 may include a conduit (not shown) that delivers the liquid fuel 194 directly through the plenum 402 to the inlet 422. The fuel source 190 may include any form of fuel atomizer that disperses the liquid fuel 194. In either case, the high-pressure air 180 passes through the mixing conduits 240, 440, thereby conveying the high-pressure air 180 (and possibly the liquid fuel 194) to the main passages 226, 426. Within the main passages 226 , 426 , the high pressure air 180 draws the low pressure air 186 and the liquid fuel 194 into and out of the passages, creating a mixture of high pressure air 180 , low pressure air 186 , and liquid fuel 194 .

[0062] In another embodiment, the combustor may be a combined combustor that uses both gas fuel 192 and liquid fuel 194, where the fuel source 190 is further configured to deliver the gas fuel 192 and the liquid fuel 194 to each of the first and second fuel nozzles 170, 172. The fuel source 190 may deliver the gas fuel 192 to the plenums 232, 432 and the liquid fuel to the inlets 222, 422 of the main passages 226, 426, respectively, as described herein.

[0063] The disclosed embodiments provide a head-end assembly 142, 342 that provides airflow and fuel at two different pressures to the primary combustion zone 108. Additionally, the disclosed embodiments provide a fuel nozzle assembly that delivers airflow and fuel at two different pressures to the primary combustion zone 108 and the secondary combustion zone 110. The disclosed embodiments allow both the primary and secondary combustion zones to utilize ejector-type premix fuel nozzles. The fuel nozzles are fuel-flexible (gas and / or liquid), reducing overall system pressure drop while maintaining the dP / P required for cooling, providing excellent premixing and achieving low emissions. This approach also enhances the cooling effect of available cooling air, thereby reducing overall system pressure drop. Additionally, this approach allows liquid fuel atomizers to be installed in the breech assembly within the head-end assembly 142, 342, achieving ease of installation, compactness, rapid repair, and cost savings.

[0064] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural unless expressly stated otherwise. It will be further understood that the terms "comprise" and / or "comprising," as used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or sets thereof. "Optional" or "optionally" means that the subsequently-stated event or circumstance may or may not occur, and the description is meant to include instances in which the event occurs and instances in which it does not occur.

[0065] As used herein throughout this specification and claims, approximation language can be applied to modify any quantitative expression that can reasonably vary without resulting in a change in the basic function involved. Thus, values modified by terms such as "approximately," "about," and "substantially" are not limited to the exact value specified. In at least some instances, approximation language can correspond to the precision of the instrument used to measure the value. Here, and throughout this specification and claims, range limitations are combinable and / or interchangeable, and unless the context and language dictate otherwise, such ranges are identified and include all subranges encompassed therein. "About," as applied to a particular value in a range, applies to both values and can indicate + / - 10% of the stated value, unless specifically dependent on the precision of the instrument used to measure the value.

[0066] The corresponding structure, material, acts, and equivalents of all means-plus-function or step-plus-function elements in the following claims are intended to encompass any structure, material, or acts for performing that function in combination with other specifically claimed claim elements. The description of the present disclosure has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the disclosure. The present embodiments were chosen and described in order to best explain the principles and practical application of the disclosure and to enable others skilled in the art to understand the disclosure in its various embodiments with various modifications as suited to the particular uses envisioned. [Explanation of symbols]

[0067] 100 Gas Turbine (GT) System 102 Intake section 104 Compressor 106 Combustion Section 108 Primary Combustion Zone 110 Secondary Combustion Zone 120 Turbine Section 121 Shaft / Rotor 122 Exhaust Section 123 Inlet guide vane (IGV) 124 Load 126 Can-type annular combustor 128 Transition Piece 129 Hot Combustion Gas Stream 130 Turbine nozzle 132 Compressor discharge casing / outer casing 134 End cover 142 Combustor Head End Assembly 144 Flow Sleeve 146 Combustor liner 147 Flow Sleeve 148 Circular Section 150 Cooling opening 152 series of vanes and blades 154 Diffuser 160 Combustion Area 162 High Pressure Air Plenum 164 High Pressure (HP) Air Source 170 First Fuel Nozzle 172 Second Fuel Nozzle 180 Compressed Air / First Compressed Air 182 Exterior 186 Low Pressure Air / Second Air Stream 188 Low Pressure (LP) Air Source 190 Fuel source 192 Gas Fuel 194 Liquid fuel 200 The First Wall 202 First Plenum 204 Headend Placement 206 Connector passage 208 Head End Plenum 210 outer annular wall / first annular wall 212 First Aspect 214 Second Aspect 220 First Circular Wall 222 Entrance 224 Exit 226 Main aisle 230 Second Circular Wall 232 Second Plenum 236 Fuel manifold 238 Conduit 240 Mixing conduit 242 Injection hole 244 Entrance 246 Exit 250 aisles 260 fuel / air mixture 262 Concentric Rings 264 Concentric Rings 290 Integrated Combustor Nozzle (ICN) 292 Segmented Annular Combustor 300 The First Wall 301 Axial center line 302 Inner liner segment 303 High Pressure Plenum / High Pressure Head End Plenum 304 Outer liner segment 306 End 307 Area 308 Low Pressure Head End Plenum 309 Second Wall 310 Fuel Injection Panel 311 Outer side 312 First Aspect 314 Second Aspect 322 Entrance 329 Combustion Gas Stream 334 Upstream Plate 342 Headend Assembly 344A Inner Flow Sleeve 344B Outer Flow Sleeve 346 Combustion Liner 350 Cooling opening 364 High-Pressure Air Source 387 Inner Plenum 388 Low-Pressure Air Source 389 Outer Plenum 402 Plenum 420 First Circular Wall 422 Entrance 424 Exit 426 Main aisle 430 Second Circular Wall 432 Plenum 433 Aperture 437 Exterior 438 Third Circular Wall 440 Mixing conduit 442 Injection hole 444 Entrance 446 Exit 450 aisle 460 mixed fuel / air stream 4-4 Line of sight 5-5 Line of sight 6-6 Line of sight C L center line P1 First pressure P2 Second pressure α angle

Claims

1. A combustor (126) for a gas turbine (GT) system (100), the combustor (126) comprising: a combustor liner (146) defining a combustion region (160) including a primary combustion zone (108) and a secondary combustion zone (110) downstream from the primary combustion zone (108); a flow sleeve (144, 147, 344A, 344B) surrounding at least a portion of the combustor liner (146), the flow sleeve (144, 147, 344A, 344B) including a plurality of cooling openings (150, 350) therein for directing a first airflow from a first air source at a first pressure to cool an outer surface (182, 437) of the combustor liner (146) and for generating a second airflow at a second pressure lower than the first pressure within an annulus (148) between the combustor liner (146) and the flow sleeve (144, 147, 344A, 344B); a first fuel nozzle (170) positioned in the primary combustion zone (108); a second fuel nozzle (172) positioned in the secondary combustion zone (110); a fuel source (190) configured to deliver a first fuel (192) to each of the first and second fuel nozzles (170, 172); It is equipped with the first and second fuel nozzles (170, 172) generate a premixture of the first airflow and the first fuel (192) and a mixture of the premixture and the second airflow (186) before introducing the mixture into a respective primary combustion zone (108) or secondary combustion zone (110); the first fuel nozzles include a plurality of first fuel nozzles positioned in a combustor head-end assembly that defines at least a portion of a head end of the combustor liner and the combustion region, each of the plurality of first fuel nozzles sharing a common first plenum in the combustor head-end assembly, and each of the plurality of first fuel nozzles including a first passage having an outlet that opens to the combustion region within the combustor liner; the first air source includes a flow path defined between a compressor discharge housing and at least a portion of the flow sleeve, the flow path being in fluid communication with the compressor, and a conduit traversing the annulus fluidly coupling the first plenum with the first air source.

2. The first and second fuel nozzles (170, 172) each include: a first annular wall (220) defining the first passage (226) in fluid communication with the second air stream (186); a second wall (200) defining a first plenum (202) in fluid communication with the first air source; a third wall (230) defining a second plenum (232) in fluid communication with the fuel source (190) for generating a flow of the first fuel (192) therein, the third wall (230) being at least partially surrounded by the second wall (200); a mixing conduit (240) extending through the second plenum (232) and fluidly connecting the first plenum (202) and the first passage (226), the mixing conduit (240) defining at least one injection hole (242) in fluid communication with the second plenum (232); The combustor (126) of claim 1, comprising:

3. the combustor head-end assembly (142) defines a head-end plenum (202, 208, 232, 402, 432) with either a) the flow sleeve (144, 147, 344A, 344B), or b) the flow sleeve (144, 147, 344A, 344B) and an end cover (134), the head-end plenum (202, 208, 232, 402, 432) receiving the second airflow (186) from the annulus (148); The combustor of any preceding claim, wherein each first passage of the plurality of first fuel nozzles includes an inlet in fluid communication with the head end plenum.

4. 3. The combustor of claim 2, further comprising a fuel manifold fluidly coupling each of the second plenums in the combustor head end assembly to the fuel source, the fuel source being fluidly coupled to the fuel manifold, and the first fuel comprising gas.

5. 2. The combustor of claim 1, wherein the combustor head-end assembly is arcuate, and the combustor is an annular combustor in which a plurality of the arcuate combustor head-end assemblies collectively form the head end of the combustion region.

6. The combustor (126) of claim 5, wherein the second fuel nozzle (172) is part of an integrated combustor nozzle (ICN (290)).

7. The combustor of claim 1, wherein the combustor head-end assembly is substantially circular and the plurality of first fuel nozzles are arranged in an annular pattern facing the combustion region.

8. The combustor of claim 7, wherein the plurality of first fuel nozzles are disposed in the combustor head end assembly within a pair of concentric rings facing the combustion region.

9. 2. The combustor of claim 1, wherein at least one of the plurality of first fuel nozzles has the outlet that opens to the combustion zone in the combustor liner that is positioned at a non-perpendicular angle relative to the combustor head-end assembly.

10. 3. The combustor of claim 2, wherein the first passage of the second fuel nozzle includes an outlet that opens to the combustion zone in the combustor liner, whereby an output of the second fuel nozzle is directed substantially radially into the combustor liner.

11. 3. The combustor of claim 2, wherein the first fuel comprises gas, the first airflow passing through the mixing conduit entrains the first fuel from the at least one injection hole to generate the premixture of the first airflow and the first fuel, the mixing conduit conveys the premix to the first passage, and within the first passage, the premix draws the second airflow into and out of the first passage to generate the mixture of the premix and the second airflow.

12. the first fuel (192) comprises a liquid, and each first passage (226) includes an inlet (222) through which the fuel source (190) delivers the first fuel (192); 3. The combustor of claim 2, wherein a first airflow passing through the mixing conduit carries the first airflow to the first passageway within which the first airflow draws the second airflow and a flow of a second fuel into and out of the first passageway to generate a mixture of the first airflow, the second airflow, and the first fuel.

13. the fuel source (190) is further configured to deliver the first fuel (192), which is a gas, and the second fuel (194), which is a liquid, to each of the first and second fuel nozzles (170, 172); 3. The combustor of claim 2, wherein the fuel source delivers the first fuel to the second plenum and the second fuel to the inlet of the first passage.

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