JP2014122784A - System for supplying fuel to combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system for supplying fuel to a combustor, the system having a combustion chamber and a liner that circumferentially surrounds at least a portion of the combustion chamber.SOLUTION: A plurality of fuel nozzles are radially arranged across the combustor upstream from the combustion chamber to supply a swirling flow of the fuel into the combustion chamber. A first fuel injector downstream from the plurality of fuel nozzles provides fluid communication for the fuel to flow through the liner and into the combustion chamber. The first fuel injector is circumferentially clocked with respect to the swirling flow of the fuel in the combustion chamber.

Description

  The present invention generally relates to a system for supplying fuel to a combustor. In certain embodiments, the combustor may be incorporated into a gas turbine or another turbomachine.

  Combustors are widely used in industrial power generation operations to ignite fuel and produce combustion gases having high temperatures and high pressures. For example, turbomachines such as gas turbines typically include one or more combustors to generate power or thrust. A typical gas turbine includes an inlet section, a compressor section, a combustion section, a turbine section, and an exhaust section. An inlet section cleans and regulates the working fluid (eg, air) and supplies the working fluid to the compressor section. A compressor section increases the pressure of the working fluid and supplies the compressed working fluid to the combustion section. A combustion section mixes fuel with the compressed working fluid and ignites the mixture to produce combustion gases having a high temperature and pressure. Combustion gas flows to the turbine section where it expands to produce work. For example, the expansion of the combustion gas in the turbine section rotates the shaft connected to the generator, thereby generating electricity.

The combustion section may have one or more combustors configured in an annulus between the compressor section and the turbine section, where the temperature of the combustion gas is the thermodynamic efficiency of the combustor, the design margin And directly affects the exhaust emissions generated. For example, a high combustion gas temperature generally improves the thermodynamic efficiency of the combustor. However, when the temperature of the combustion gas is high, a flame holding state in which the combustion flame moves toward the fuel supplied by the nozzle is also promoted, so that the nozzle can be operated in a relatively short time. Damage can be accelerated. Further, when the temperature of the combustion gas is high, the dissociation rate of diatomic nitrogen generally increases, thereby increasing the amount of nitrogen oxide (NO _x ) generated in the same residence time in the combustor. Conversely, a decrease in the temperature of the combustion gas associated with decreasing fuel flow and / or partial load operation (turndown) generally decreases the chemical reaction rate of the combustion gas, thereby causing combustion. The amount of carbon monoxide produced during the same residence time in the vessel increases and unburned hydrocarbons increase.

  In certain combustor designs, the combustor can have a cap assembly that extends radially across at least a portion of the combustor, and one or more fuel nozzles provide fuel to the combustor. It can be arranged radially across the cap assembly for delivery. The fuel nozzle may have a swirler vane and / or another to enhance mixing between the fuel and the compressed working fluid to produce a lean fuel-air mixture for combustion. Can have a flow guide. A swirling fuel-air mixture flows into the combustion chamber where it is ignited to generate combustion gases. The combustor can further include one or more fuel injectors disposed circumferentially around the combustion chamber to provide additional fuel for performing combustion. The additional fuel supplied by the fuel injector raises the firing temperature of the combustor without correspondingly increasing the residence time of the combustion gases in the combustion chamber.

While effective to allow the operating temperature to be raised, the placement of fuel injectors axially and circumferentially around the combustion chamber can produce undesirable emissions and / or Or it can have a significant impact on component wear. For example, a fuel injector that injects fuel directly into a combusting fuel-air mixture flowing from a fuel nozzle can create undesirable hot streaks within the combustor, thereby causing NO _x emissions. The amount may increase and low cycle fatigue of the component may be reduced. In other cases, fuel injectors that inject fuel from too far away from the burning fuel-air mixture flowing from the fuel nozzle may cause incomplete combustion of the fuel, thereby Carbon monoxide and unburned hydrocarbon production may increase. Thus, to supply fuel to the combustor that indexes or clocks the fuel injector to the fuel nozzle and / or to the swirling fuel-air mixture flowing from the fuel nozzle. This system may allow the temperature of the combustor to be raised over a wide range of operating conditions without a corresponding increase in undesirable emissions and / or a corresponding acceleration of component wear.

U.S. Pat. No. 8,112,216

  Aspects and advantages of the present invention are set forth in the following description, or may be obvious from the following description, or understood by practicing the invention.

  One embodiment of the present invention is a system for supplying fuel to a combustor having a combustion chamber and a liner that circumferentially surrounds at least a portion of the combustion chamber. A plurality of fuel nozzles are disposed radially across the combustor upstream of the combustion chamber to provide a swirling fuel flow into the combustion chamber. A first fuel injector downstream of the plurality of fuel nozzles provides fluid communication for allowing fuel to flow through the liner into the combustion chamber. The first fuel injector is clocked in the circumferential direction with reference to the swirling fuel flow in the combustion chamber.

  Another embodiment of the present invention is a system for supplying fuel to a combustor having a combustion chamber and a liner that circumferentially surrounds at least a portion of the combustion chamber. A plurality of fuel nozzles are disposed radially across the combustor upstream of the combustion chamber to provide a swirling fuel flow into the combustion chamber. A first set of fuel injectors is disposed circumferentially around the liner downstream of the plurality of fuel nozzles. This first set of fuel injectors provides fluid communication for allowing fuel to flow through the liner into the combustion chamber and is clocked circumferentially with reference to the swirling fuel flow in the combustion chamber.

  The present invention may also include a gas turbine having a compressor, a combustor downstream of the compressor, and a turbine downstream of the combustor. A plurality of fuel nozzles are arranged radially inside the combustor and a combustion chamber is downstream of the plurality of fuel nozzles. A plurality of fuel nozzles supply a swirling fuel flow into the combustion chamber. A first set of fuel injectors is disposed circumferentially around the combustion chamber downstream of the plurality of fuel nozzles. This first set of fuel injectors forms fluid communication for allowing fuel to flow into the combustion chamber and is clocked circumferentially with reference to the swirling fuel flow in the combustion chamber.

  Those skilled in the art will better appreciate the features and aspects of these and other embodiments upon reading this specification.

  The complete, operable disclosure of the present invention, including the best mode, directed to those skilled in the art is presented in more detail in the remainder of this specification, including reference to the accompanying drawings.

1 is a functional block diagram illustrating an exemplary gas turbine within the scope of the present invention. FIG. 2 is a simplified cross-sectional side view of an exemplary combustor according to various embodiments of the present invention. FIG. FIG. 3 is a partially enlarged side sectional view showing a cap assembly and a fuel nozzle shown in FIG. 2. FIG. 3 is an enlarged side cross-sectional view illustrating the exemplary fuel injector shown in FIG. 2. FIG. 3 is a perspective side cross-sectional view of a portion of the combustor shown in FIG. 2 is a graph showing a set of discharge curves at various temperatures.

  Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. This detailed description uses numerical designations and letter designations to indicate features in the drawings. Similar or similar designations in the drawings and description are used to refer to similar or similar parts of the invention. As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another component, and individual components It is not intended to indicate the location or importance of. Further, the terms “upstream”, “downstream”, “radial direction”, and “axial direction” indicate relative directions based on the fluid flow in the fluid path. For example, “upstream” means the direction in which the fluid flows, and “downstream” means the direction in which the fluid flows. Similarly, “radial direction” means a relative direction substantially perpendicular to the fluid flow, and “axial direction” means a relative direction substantially parallel to the fluid flow.

  Each example is provided by way of explanation of the invention, not limitation of the invention. Indeed, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For example, features shown or described as part of one embodiment can be used in another embodiment to yield a still further embodiment. Accordingly, the present invention is intended to embrace such modifications and variations that fall within the scope of the appended claims and their equivalents.

  Various embodiments of the present invention include a system for supplying fuel to a combustor. The combustor generally has a cap assembly that extends radially across at least a portion of the combustor, and a plurality of fuel nozzles radially disposed within the cap assembly provide a fuel flow that swirls into the combustion chamber. Supply. One or more fuel injectors may be circumferentially arranged around the combustion chamber to supply fuel into the combustion chamber, each fuel injector circumferentially with respect to the swirling fuel flow in the combustion chamber Indexed or clocked in direction. In certain embodiments, the fuel injectors can be aligned with each other in the axial direction, and in another particular embodiment, the fuel injectors can be staggered in the axial direction within the combustion chamber. Alternatively or additionally, the fuel injector may intersect the combustion chamber to be perpendicular to the tangential direction of the combustion chamber, or may intersect the combustion chamber at a compound angle in some embodiments. Also good. Accordingly, various embodiments of the present invention extend the operating state of the combustor, extend the life and / or maintenance intervals of various combustor components, and maintain a sufficient design margin for flame holding. And / or reducing undesirable emissions. While exemplary embodiments of the present invention are generally described in the context of a combustor incorporated into a gas turbine for purposes of explanation, those skilled in the art will understand that any embodiment in which the present invention is incorporated into any turbomachine. It will be readily appreciated that it may be applied to a combustor and is not limited to a gas turbine combustor unless specifically stated in the claims.

  Referring now to the drawings wherein like reference numerals indicate like elements throughout the several views, FIG. 1 illustrates a functional block diagram of an exemplary gas turbine 10 that may incorporate various embodiments of the present invention. providing. As shown, the gas turbine 10 is generally a continuous filter, cooling coil, moisture separator for purifying or otherwise conditioning the working fluid (eg, air) 14 entering the gas turbine 10. And / or an inlet section 12 that may include another device. The working fluid 14 flows to the compressor section where the compressor 16 continuously applies kinetic energy to the working fluid 14, thereby producing a high energy state compressed working fluid 18. The compressed working fluid 18 flows to the combustion section, where one or more combustors 20 use the compressed working fluid 18 to ignite the fuel 22, thereby producing combustion gases 24 having a high temperature and high pressure. . Combustion gas 24 flows through the turbine section, thereby generating work. For example, the turbine 26 may be connected to the shaft 28, in which case the rotation of the turbine 26 drives the compressor 16, thereby producing the compressed working fluid 18. Alternatively or additionally, the shaft 28 may connect the turbine 26 to the generator 30 to generate electricity. Exhaust gas 32 from turbine 26 flows through an exhaust section 34 that can connect turbine 26 to an exhaust stack 36 downstream of turbine 26. The exhaust section 34 includes, for example, a heat recovery steam generator (not shown) for cleaning the exhaust gas 32 and extracting additional heat from the exhaust gas 32 before releasing the exhaust gas 32 to the environment. Can have.

  The combustor 20 may be any type of combustor known in the art, but the invention is not limited to any particular combustor design unless specifically stated in the claims. FIG. 2 provides a simplified cross-sectional side view of an exemplary combustor 20 according to various embodiments of the present invention. As shown in FIG. 2, the casing 40 and end cover 42 may be combined to contain the compressed working fluid 18 that flows to the combustor 20. A cap assembly 44 may extend radially across at least a portion of the combustor 20 and one or more fuel nozzles 46 supply fuel 22 to a combustion chamber 48 downstream of the cap assembly 44. For this purpose, it can be arranged radially across the cap assembly 44. A liner 50 may circumferentially surround at least a portion of the combustion chamber 48 and a transition duct 52 downstream of the liner 50 may connect the combustion chamber 48 to the inlet of the turbine 26. A collision sleeve 54 with a flow hole 56 may surround the transition duct 52 circumferentially and a flow sleeve 58 may surround the liner 50 circumferentially. This allows the compressed working fluid 18 to pass through the flow holes 56 in the impingement sleeve 54, and thus an annular passage outside the transition duct 52 and liner 50 to convectively cool the transition duct 52 and liner 50. 60 can flow through. As the compressed working fluid 18 reaches the end cover 42, the compressed working fluid 18 reverses direction and flows through the fuel nozzle 46 and cap assembly 44 into the combustion chamber 48.

  Although the present invention is not limited to any particular cap assembly 44 or fuel nozzle 46 unless specifically stated in the claims, FIG. 3 illustrates an exemplary cap assembly 44 and fuel nozzle 46 within the scope of the present invention. An enlarged partial side sectional view is provided. As shown in FIG. 3, each fuel nozzle 46 can generally have a central body 62 surrounded by a shroud 64, and an annular passage 66 is defined between the central body 62 and the shroud 64. The central body 62 generally extends axially from the end cover 42 toward the cap assembly 44 so that fuel 22, diluent and / or another additive passes from the end cover 42 through the central body 62. Thus, fluid communication for flowing into the combustion chamber 48 is formed. The shroud 64 can have a bell mouth opening 68 to facilitate the radial distribution of the compressed working fluid 18 flowing through the annular passage 66 between the central body 62 and the shroud 64. In addition, one or more vanes 70 may extend radially between the central body 62 and the shroud 64, thereby adding a tangential swirl to the compressed working fluid 18, which This enhances the mixing of the compressed working fluid 18 and the fuel 22 before combustion.

  Referring again to FIG. 2, the combustor 20 can further include one or more fuel injectors 80 downstream of the fuel nozzle 46, which one or more fuel injectors 80 combust. Thus, the fuel 22 and the compressed working fluid 18 can be delayed and lean injected. Although the present invention is not limited to any particular fuel injector 80 unless specifically stated in the claims, FIG. 4 provides an enlarged side cross-sectional view of an exemplary fuel injector 80 within the scope of the present invention. As shown in FIG. 4, the fuel injector 80 may have a tube 82 or another passage that provides fluid communication through the flow sleeve 58 and liner 50 to the combustion chamber 48. In the exemplary embodiment shown in FIG. 4, the tube 82 is substantially perpendicular to the flow sleeve 58 and the liner 50, and thus injects a fuel-air mixture transversely to the combustion chamber 48. However, in other embodiments, the tube 82 may be angled axially and / or circumferentially with respect to the flow sleeve 58 and / or the liner 50.

  The flow sleeve 58 can have an internal fuel passage 84, and each tube 82 can have one or more fuel ports 86 disposed circumferentially around the tube 82. An internal fuel passage 84 can supply fuel port 86 with fuel that is equal to or different from the fuel supplied to fuel nozzle 46. Thus, the fuel port 86 can form fluid communication to allow the fuel 22 to flow into the tube 82, thereby allowing the fuel 22 and the fuel 22 to pass through the tube 82 and into the combustion chamber 48. It is possible to mix with the compressed working fluid 18. In this way, the tube 82 provides a lean mixture of the fuel 22 and the compressed working fluid 18 for further combustion with the purpose of raising the temperature of the combustor 20 and thereby improving efficiency. Will be able to.

  FIG. 5 provides a perspective side cross-sectional view of a portion viewed from the upstream side of the combustor 20 shown in FIG. 2 to illustrate the position of the fuel injector 80 relative to the fuel nozzle 46. As shown in FIG. 5, vanes 70 in fuel nozzle 46 add tangential vortices to fuel 22 and compressed working fluid 18 flowing through an annular passage 66 between central body 62 and shroud 64. As a result, each fuel nozzle 46 provides a swirling individual fuel stream 90 that moves in a spiral at low speed through the combustion chamber 48 in the downstream direction as it burns. In the particular embodiment shown in FIG. 5, a first set of fuel injectors 92 is disposed circumferentially around the liner 50 downstream of the fuel nozzle 46 and a second set of fuel injectors 94 is the first. It is arranged circumferentially around the liner 50 downstream of one fuel injector set 92. Each fuel injector 80 in each set 92, 94 of fuel injectors has an axial position that is equal to another fuel injector 80 in the same set 92, 94. Further, each fuel injector 80 in each set 92, 94 of fuel injectors is indexed or clocked circumferentially with respect to the swirling fuel flow 90 from another fuel nozzle 46. As used herein, the term “clocked” or “clocked” means that each fuel injector 80 is positioned at a desired circumferential offset 96 relative to the swirling fuel flow 90. . The circumferential offset 96 between each fuel injector 80 and swirling fuel flow 90 can cause undesirable hot streaks and incomplete fuel 22 as occurs in conventional delayed lean injection systems and methods. Avoid burning or mitigating them. Further, in the particular embodiment shown in FIG. 5, each fuel injector 80 is angled axially and circumferentially, so each fuel injector 80 intersects the liner 50 at a compound angle, Thereby, the benefits of clocking the fuel injector 80 with respect to the swirling fuel flow 90 are further increased.

  The optimal clock amount, i.e., the optimal circumferential offset 96 between each fuel injector 80 and the swirling fuel flow 90, may vary depending on various factors, including the number of fuel nozzles 46. , The size of the vortex induced by each fuel nozzle 46, the number of fuel injectors 80, the axial and / or circumferential angle of the fuel injectors 80, and the expected operating level of the combustor 20, etc. is there. For example, the optimal clock or circumferential offset 96 is about ± 2-15 degrees for a combustor 20 with five or more fuel nozzles 46 and for a combustor 20 with four fuel nozzles 46. It is about ± 10 degrees to 25 degrees, and in the case of the combustor 20 including three or less fuel nozzles 46, it is about ± 20 degrees to 45 degrees.

The unique clock or circumferential offset 96 of each embodiment can be determined empirically through computational fluid dynamics models and / or experiments. For example, FIG. 6 provides a set of emissions curves for the inherent circumferential offset 96 of the fuel nozzle 46 and the first and second fuel injector sets 92 and 94. As expected, when the carbon monoxide emission curve 100 uses only the fuel nozzle 46, the combustion temperature is associated with a decrease in fuel flow and / or partial load operation (turndown). It shows that the carbon monoxide emission increases greatly by lowering. During turndown operation, additional fuel 22 is supplied through the first set of fuel injectors 92 or through both the first set of fuel injectors 92 and the second set of fuel injectors 94. By doing so, the carbon monoxide emission curve 100 moves to the right. Conversely, when the NO _x emission curve 102 uses only the fuel nozzle 46, the NO _x emission increases significantly due to the combustion temperature rising accompanying the full load operation, During full load operation, additional fuel 22 is supplied through the first set of fuel injectors 92 or through both the first set of fuel injectors 92 and the second set of fuel injectors 94. This indicates that the NO _x emission amount curve 102 moves to the right side. Thus, the NO _x emission curve 102 shows that the lean fuel 22 supplied by the first fuel injector set 92 and the second fuel injector set 94 is increased before the NO _x emission increases significantly. It shows that the combustion temperature can be raised. The additional emission curves 100, 102 shown in FIG. 6 are empirically determined by a first fuel injector set 92 and a second fuel injector set 94 that are clocked with various circumferential offsets 96. Experimentally obtained, the optimal circumferential offset 96 may be selected based on the collection of emission curves 100, 102 and the expected operating schedule of the combustor 20.

The various embodiments described and illustrated in connection with FIGS. 1-5 can provide one or more advantages over existing systems. For example, by combining the axial position of the fuel injector 80, which is clocked to the fuel stream 90 to pivot to various, it is possible to increase the combustion temperature before NO _X emissions increase dramatically obtain. Thus, the wide range of combustor temperatures improves the thermodynamic efficiency of the gas turbine 10 without a corresponding increase in undesirable emissions.

  This description is intended to enable a person skilled in the art to disclose the invention, including the best mode, as well as to make and use any device or system and implement any method employed. Several embodiments are used to enable the practice of the present invention. 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 alternative embodiments include structural elements that do not differ from the language of the claims, or equivalent structural elements that do not substantially differ from the language of the claims. Is intended to be within the scope of

DESCRIPTION OF SYMBOLS 10 Gas turbine 12 Inlet section 14 Working fluid 16 Compressor 18 Compressed working fluid 20 Combustor 22 Fuel 24 Combustion gas 26 Turbine 28 Shaft 30 Generator 32 Exhaust gas 34 Exhaust section 36 Exhaust pipe 40 Casing 42 End cover 44 Cap assembly 46 Fuel nozzle 48 Combustion chamber 50 Liner 52 Transition duct 54 Collision sleeve 56 Flow hole 58 Flow sleeve 60 Annular passage 62 Central body 64 Fuel nozzle shroud 66 Annular passage 68 Bell mouth opening 70 Blade 80 Fuel injector 82 Tube 84 Fuel passage 86 Fuel Port 90 Swirling fuel flow 92 First fuel injector set 94 Second fuel injector set 96 Circumferential offset 100 CO emission curve 102 NO _X emission curve

Claims (20)

A system for supplying fuel to a combustor,
a. A combustion chamber;
b. A liner circumferentially surrounding at least a portion of the combustion chamber;
c. A plurality of fuel nozzles disposed radially across the combustor upstream of the combustion chamber, wherein the plurality of fuel nozzles supply a fuel flow that swirls into the combustion chamber;
d. A first fuel injector downstream of the plurality of fuel nozzles, wherein the first fuel injector forms fluid communication for fuel to flow through the liner into the combustion chamber; A fuel injector,
With
e. The first fuel injector is clocked circumferentially with respect to the swirling fuel flow in the combustion chamber;
system. The system of claim 1, wherein each fuel nozzle comprises a plurality of swirler blades extending radially between the central body and the shroud. The system of claim 1, wherein the first fuel injector intersects the liner at a compound angle. A second fuel injector downstream of the plurality of fuel nozzles, the second fuel injector forming fluid communication for fluid to flow through the liner into the combustion chamber; The system of claim 1, wherein two fuel injectors are clocked circumferentially with respect to the swirling fuel flow in the combustion chamber. The system of claim 4, wherein the second fuel injector is substantially evenly aligned with the first fuel injector in an axial direction. The system of claim 4, wherein the second fuel injector is axially aligned downstream of the first fuel injector in the combustion chamber. The system of claim 4, wherein the second fuel injector intersects the liner at a compound angle. The system of claim 1, further comprising a flow sleeve circumferentially surrounding at least a portion of the liner and a fuel plenum internal to the flow sleeve in fluid communication with the first fuel injector. A system for supplying fuel to a combustor,
a. A combustion chamber;
b. A liner circumferentially surrounding at least a portion of the combustion chamber;
c. A plurality of fuel nozzles disposed radially across the combustor upstream of the combustion chamber, wherein the plurality of fuel nozzles supply a fuel flow that swirls into the combustion chamber;
d. A first set of fuel injectors disposed circumferentially around the liner downstream of the plurality of fuel nozzles, wherein the first set of fuel injectors passes fuel through the liner; A first set of fuel injectors forming fluid communication for flowing into the combustion chamber;
e. The first set of fuel injectors is clocked circumferentially with respect to the swirling fuel flow in the combustion chamber;
system. The system of claim 9, wherein each fuel nozzle comprises a plurality of swirler vanes extending radially between the central body and the shroud. The system of claim 9, wherein each fuel injector in the first set of fuel injectors intersects the liner at a compound angle. And further comprising a second set of fuel injectors disposed circumferentially around the liner downstream of the first set of fuel injectors, wherein the second set of fuel injectors comprises fuel Forming fluid communication for flow through a liner to the combustion chamber, wherein the second set of fuel injectors are clocked circumferentially with respect to the swirling fuel flow in the combustion chamber. 9. The system according to 9. The system of claim 12, wherein the second set of fuel injectors is aligned in the combustion chamber in an axial direction downstream of the first set of fuel injectors. The system of claim 12, wherein each fuel injector in the second set of fuel injectors intersects the liner at a compound angle. The system of claim 9, further comprising a flow sleeve that circumferentially surrounds at least a portion of the liner and a fuel plenum internal to the flow sleeve that is in fluid communication with the first set of fuel injectors. . a. A compressor,
b. A combustor downstream of the compressor;
c. A turbine downstream of the combustor;
d. A plurality of fuel nozzles arranged radially in the combustor;
e. A combustion chamber downstream of the plurality of fuel nozzles, wherein the plurality of fuel nozzles supply a swirling fuel flow into the combustion chamber; and
f. A first set of fuel injectors disposed circumferentially around the combustion chamber downstream of the plurality of fuel nozzles, wherein the first set of fuel injectors provides fuel to the combustion chamber; A first set of fuel injectors that form fluid communication for flow;
With
g. The first set of fuel injectors is clocked circumferentially with respect to the swirling fuel flow in the combustion chamber;
gas turbine. The gas turbine of claim 16, wherein each fuel injector in the first set of fuel injectors intersects the liner at a compound angle. And further comprising a second set of fuel injectors disposed circumferentially around the combustion chamber downstream of the first set of fuel injectors, the second set of fuel injectors comprising fuel The gas of claim 16, wherein fluid gas is formed for flow into the combustion chamber, and the second set of fuel injectors are clocked circumferentially with respect to the swirling fuel flow in the combustion chamber. Turbine. The gas turbine of claim 18, wherein the second set of fuel injectors is axially aligned within the combustion chamber downstream of the first set of fuel injectors. The gas turbine of claim 18, wherein each fuel injector in the second set of fuel injectors intersects the combustion chamber at a compound angle.