Combustion section with primary burner and a set of secondary burners

Abstract

A turbine engine has a compressor section, a combustion section, and a turbine section arranged in series along the engine centerline. A combustion section for the turbine engine has a primary burner bushing comprising an inner liner and an outer liner arranged annularly around the engine centerline. A dome wall extends between the inner and outer liners. A set of primary dome inlets is located in the dome wall and arranged circumferentially around the engine centerline. A set of secondary burners is fluidly coupled to the primary combustion chamber, the set of secondary burners including a first miniature burner and a second miniature burner.

Description

Technical Field

[0001] This topic generally relates to the combustion section of a turbine engine, and more specifically, to the combustion section having a primary burner and a secondary burner. Background Technology

[0002] A turbine engine is driven by a flow of combustion gases through the engine to rotate multiple turbine blades, which in turn rotate a compressor, thereby supplying compressed air to a combustor for combustion. The combustor can be located within the turbine engine and fluidly connected to the turbine through which the combustion gases flow.

[0003] Hydrocarbon fuels are known to be used in the combustors of turbine engines. Typically, air and fuel are fed into the combustion chamber, where the air mixes with the fuel, and the fuel is then burned in the presence of air to produce hot gases. These hot gases are then fed into the turbine, where they are cooled and expanded to generate power. Byproducts of fuel combustion typically include environmentally harmful byproducts such as nitrogen oxides and nitrogen dioxide (collectively known as NO). x Carbon monoxide (CO), unburned hydrocarbons (UHC) (e.g., methane and volatile organic compounds that contribute to the formation of atmospheric ozone), and other oxides including sulfur oxides (e.g., SO2 and SO3).

[0004] Various fuels for combustion in turbine engines are being explored. Hydrogen, or hydrogen mixed with another element or compound, can be used for combustion; however, hydrogen or hydrogen-blended fuels can result in higher flame temperatures than conventional fuels. That is, hydrogen or hydrogen-blended fuels generally have a wider combustible range and faster combustion rates than conventional fuels such as petroleum-based fuels or mixtures of petroleum and synthetic fuels.

[0005] Standards originating from global air pollution problems specify the NO generated by turbine engine operation x Emissions of UHC and CO. In particular, due to the high burner flame temperature during operation, NO is formed within the burner. x The aim is to reduce NO by adjusting the temperature distribution and / or flame pattern within the burner. x Emissions can be reduced while maintaining the desired efficiency. Attached Figure Description

[0006] In the attached diagram:

[0007] Figure 1 This is a schematic diagram of a turbine engine.

[0008] Figure 2 The combustion zone of the turbine engine is depicted along... Figure 1 A cross-sectional view of line II-II, the combustion section being at least partially defined by an outer liner and having a set of secondary burners.

[0009] Figure 3 From Figure 2 The schematic portion of the outer lining seen in line III-III.

[0010] Figure 4 It is along Figure 3 A cross-sectional view taken along line IV-IV shows a schematic diagram of the combustion zone as observed in the first radial plane.

[0011] Figure 5 It is along Figure 3 A cross-sectional view taken by the VV line shows a schematic diagram of the combustion zone as observed in a second radial plane circumferentially spaced from the first radial plane.

[0012] Figure 6A Is with Figure 2 The same cross-sectional view shows the arrangement of the first-stage miniature burner.

[0013] Figure 6B It is along Figure 3 The cross-sectional view taken by line BB shows the arrangement of the second-stage miniature burner.

[0014] Figure 7A It comes from Figure 6A A variation of the arrangement of the first-stage miniature burner.

[0015] Figure 7B It comes from Figure 6B A variation of the arrangement of the second-stage miniature burner.

[0016] Figure 8 This is based on another aspect disclosed in this article. Figure 3 A schematic diagram of a variation of a portion of the outer lining 40.

[0017] Figure 9 This is based on another aspect disclosed in this article. Figure 3 A schematic diagram of another variation of a portion of the outer lining 40.

[0018] Figure 10 This is based on another aspect disclosed in this article. Figure 3 A schematic diagram of another variation of a portion of the outer lining 40.

[0019] Figure 11 This is based on another aspect disclosed in this article. Figure 3 A schematic diagram of an additional variant of a portion of the outer lining 40.

[0020] Figure 12 This is based on another aspect disclosed in this article. Figure 3A schematic diagram of another variation of a portion of the outer lining 40.

[0021] Figure 13 This is based on another aspect disclosed in this article. Figure 3 A schematic diagram of another variation of a portion of the outer lining 40.

[0022] Figure 14 This is based on another aspect disclosed in this article. Figure 3 A schematic diagram of another variation of a portion of the outer lining 40. Detailed Implementation

[0023] The aspects of this disclosure described herein relate to combustion sections, particularly combustion sections having a primary combustor and a set of secondary combustors, wherein the set of secondary combustors is arranged to exhaust gases into the primary combustor in different orientations. For illustrative purposes, this disclosure will be described in relation to turbine engines. However, it will be understood that the aspects of the disclosure described herein are not limited thereto, and the combustion sections described herein can be implemented in engines (including, but not limited to, turbojet engines, turboprop engines, turboshaft engines, and turbofan engines). The aspects of the disclosure discussed herein are generally applicable to non-aircraft engines with combustors, such as in other mobile applications and non-mobile industrial, commercial, and residential applications.

[0024] The term "exemplary" as used herein means "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as superior to or advantageous to other implementations. Furthermore, unless explicitly stated otherwise, all embodiments described herein should be considered exemplary.

[0025] As used herein, the terms “first,” “second,” and “third” are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of the individual components.

[0026] The terms "front" and "rear" refer to relative positions within a gas turbine engine or vehicle, and specifically to the normal operating posture of the gas turbine engine or vehicle. For example, in the case of a gas turbine engine, "front" refers to the position closer to the engine inlet, while "rear" refers to the position closer to the engine nozzle or exhaust port.

[0027] As used herein, the term "upstream" refers to the direction opposite to the direction of fluid flow, while the term "downstream" refers to the direction in the same direction as the fluid flow. The terms "forward" or "front" indicate what is in front of something, and "backward" or "rear" indicate what is behind something. For example, when used in relation to fluid flow, forward / front can indicate upstream, and backward / rear can indicate downstream.

[0028] The term "fluid" can refer to either a gas or a liquid. The terms "fluid connection" and "fluid geoconnection" refer to the ability of fluids to establish a connection between specified areas.

[0029] Furthermore, as used herein, the term "radial" or "radially" refers to a direction away from a common center. For example, in the overall context of a turbine engine, radial refers to the direction along a ray extending between the engine's central longitudinal axis and the engine's outer perimeter.

[0030] All directional references (e.g., radial, axial, proximal, distal, up, down, upward, downward, left, right, lateral, front, rear, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise, upstream, downstream, forward, backward, etc.) may be used for identification purposes to aid the reader's understanding of this disclosure and do not impose limitations, particularly regarding the location, orientation, or use of aspects of the disclosure described herein. Connecting references (e.g., attachment, connection, joint, and engagement) may be used and will be interpreted broadly, and may include intermediate structural elements between sets of elements and relative movement between elements, unless otherwise indicated. Therefore, a connecting reference does not necessarily mean that two elements are directly connected and fixed relative to each other. Exemplary figures are for illustrative purposes only, and the dimensions, positions, order, and relative sizes reflected in the accompanying figures may vary.

[0031] Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” include plural references. Furthermore, as used herein, the term “group” or “set” of elements can be any number of elements, including only one.

[0032] As used herein and throughout the specification and claims, approximate language is applied to modify any quantitative representation that may allow for variation without altering its associated essential function. Therefore, values ​​modified by one or more terms such as “about,” “approximately,” “substantially,” and “basically” are not limited to the specified precise values. In at least some cases, approximate language may correspond to the precision of the instrument used to measure the value, or the precision of the method or machine used to construct or manufacture the component and / or system. For example, approximate language may refer to a margin of 1%, 2%, 4%, 5%, 10%, 15%, or 20% of the endpoints of a single value, a range of values, and / or a range of defined values. Scope limitations are combined and interchanged herein and throughout the specification and claims; such scope is identified and includes all subscopes contained herein, unless otherwise indicated by context or language. For example, all scopes disclosed herein include endpoints, and endpoints can be combined independently of each other.

[0033] Figure 1 This is a schematic diagram of a turbine engine 10. As a non-limiting example, the turbine engine 10 can be used within an aircraft. The turbine engine 10 may include at least a compressor section 12, a combustion section 14, and a turbine section 16. A drive shaft 18 rotatably connects the compressor section 12 and the turbine section 16 such that rotation of one affects rotation of the other, and defines the axis of rotation or engine centerline 20 of the turbine engine 10.

[0034] Compressor section 12 may include a low-pressure (LP) compressor 22 and a high-pressure (HP) compressor 24 fluidly connected in series with each other. Turbine section 16 may include an LP turbine 28 and an HP turbine 26 fluidly connected in series with each other. Drive shaft 18 may operatively connect the LP compressor 22, HP compressor 24, LP turbine 28, and HP turbine 26 together. Alternatively, drive shaft 18 may include an LP drive shaft (not shown) and an HP drive shaft (not shown). The LP drive shaft may connect the LP compressor 22 to the LP turbine 28, and the HP drive shaft may connect the HP compressor 24 to the HP turbine 26. The LP spool may be defined as a combination of the LP compressor 22, LP turbine 28, and LP drive shaft, such that rotation of the LP turbine 28 may apply a driving force to the LP drive shaft, which in turn may rotate the LP compressor 22. The HP spool may be defined as a combination of the HP compressor 24, HP turbine 26, and HP drive shaft, such that rotation of the HP turbine 26 may apply a driving force to the HP drive shaft, which in turn may rotate the HP compressor 24.

[0035] Compressor section 12 may include multiple axially spaced stages. Each stage includes a set of circumferentially spaced rotating blades and a set of circumferentially spaced stationary blades. Compressor blades for a stage of compressor section 12 may be mounted to a disc, which is mounted to drive shaft 18. Each set of blades for a given stage may have its own disc. The blades of compressor section 12 may be mounted to a housing that may extend circumferentially around turbine engine 10. It should be understood that the representation of compressor section 12 is merely illustrative and any number of stages may be present. Furthermore, it is contemplated that any other number of components may be present within compressor section 12.

[0036] Similar to compressor section 12, turbine section 16 may include multiple axially spaced stages, each stage having a set of circumferentially spaced rotating blades and a set of circumferentially spaced stationary blades. Turbine blades for one stage of turbine section 16 may be mounted to a disc, which is mounted to drive shaft 18. Each set of blades for a given stage may have its own disc. The blades of turbine section 16 may be circumferentially mounted to the housing. It should be noted that any number of blades, blades, and turbine stages can be present, as the illustrated turbine section is merely schematic. Furthermore, it is contemplated that any other number of components may be present within turbine section 16.

[0037] Combustion section 14 may be arranged in series between compressor section 12 and turbine section 16. Combustion section 14 may be fluidly coupled to at least a portion of compressor section 12 and turbine section 16, such that combustion section 14 at least partially fluidly couples compressor section 12 to turbine section 16. As a non-limiting example, combustion section 14 may be fluidly coupled to HP compressor 24 at its upstream end and to HP turbine 26 at its downstream end.

[0038] During operation of the turbine engine 10, ambient air or atmospheric air is drawn into the compressor section 12 via a fan (not shown) upstream of the compressor section 12, where it is compressed to define pressurized air. This pressurized air can then flow into the combustion section 14, where it mixes with fuel and is ignited to generate combustion gases. The HP turbine 26 extracts some work from these combustion gases, driving the HP compressor 24. The combustion gases are discharged into the LP turbine 28, which extracts additional work to drive the LP compressor 22, and the exhaust gas is ultimately discharged from the turbine engine 10 via an exhaust section (not shown) downstream of the turbine section 16. The drive of the LP turbine 28 drives the LP spool to rotate the fan (not shown) and the LP compressor 22. The pressurized airflow and combustion gases together define the working airflow flowing through the fan, compressor section 12, combustion section 14, and turbine section 16 of the turbine engine 10.

[0039] Figure 2 The combustion section 14 is depicted along Figure 1The image shows a cross-sectional view along line II-II, which defines a transverse plane (denoted as "TP"). Combustion section 14 may include a primary burner 32, which is annular about the engine centerline 20 and has a primary burner bushing 38. The primary burner bushing 38 includes an outer bushing 40 and an inner bushing 42 concentric with respect to each other. A dome wall 44 extends between the outer bushing 40 and the inner bushing 42. The primary combustion chamber 46 is defined at least partially by the dome wall 44 and the primary burner bushing 38. A set of primary dome inlets 66 is circumferentially arranged within the dome wall 44 about the engine centerline 20. A set of primary fuel injectors 30 is fluidly connected to the primary combustion chamber 46 via the set of primary dome inlets 66. It should be understood that the annular arrangement of the primary dome inlets 66 may be fluidly connected to one or more fuel injectors, and the one or more primary fuel injectors 30 may have different characteristics. Depending on the type of engine in which the primary burner 32 is located, the primary burner 32 may have a canister-shaped, canister-annular, or annular arrangement. In a non-limiting example, a ring-shaped arrangement is shown and disposed within the housing 36.

[0040] Combustion section 14 also includes a circumferential arrangement of miniature combustors 34 defining a set of secondary combustors 50. As used herein, “miniature” means that a component referred to by the term miniature is smaller than a corresponding similar component without the term miniature (i.e., miniature combustor 34 is smaller than primary combustor 32). Each miniature combustor 34 in the set of secondary combustors 50 is defined by a secondary combustor bushing 52 extending substantially perpendicularly from primary combustor bushing 38. The secondary combustor bushing 52 defines at least a portion of secondary combustion chambers 54 circumferentially spaced around engine centerline 20. The set of secondary combustors 50 is fluidly connected to primary combustor 32 via a set of openings 57 extending through liner 40. More specifically, the secondary combustion chambers 54 terminate at the set of openings 57 to define secondary combustor outlets 58. In a non-limiting example, each secondary combustion chamber 54 in the set of secondary combustors 50 is radially aligned with primary fuel injector 30. A set of primary dilution openings 72 may include a plurality of dilution openings 59 arranged circumferentially around the engine centerline 20 and located in the liner 42.

[0041] Primary burner 32 produces primary exhaust gas (denoted as "G1") in primary combustion chamber 46. The set of secondary burners 50 produces secondary exhaust gas (denoted as "G2") in secondary combustion chamber 54 that flows into primary combustion chamber 46. Secondary exhaust gas G2 circulates in primary combustion chamber 46, resulting in insufficient O2 levels and lowering the temperature within primary combustion chamber 46. This leads to NO... x Emissions reduction. The dilution stream (denoted as "D") enters the primary combustion chamber 46 via the set of primary dilution openings 72 to adjust the outlet temperature distribution and to complete combustion if any unburned products are present downstream of the set of secondary burners 50.

[0042] The group of secondary burners 50 includes at least a first miniature burner 34a and a second miniature burner 34b. Figure 5 The first-stage miniature burner 65 includes at least the first and third miniature burners 34a and 34c, and the remaining miniature burners 34 shown. The set of openings 57 is a plurality of openings including at least the first opening 57a and the third opening 57c. The first opening 57a corresponds to the first miniature burner 34a, and the third opening 57c corresponds to the third miniature burner 34c. The primary fuel injector 30 includes at least the first primary fuel injector 30a, the second primary fuel injector 30b, and the third primary fuel injector 30c.

[0043] Figure 3 From Figure 2 A schematic diagram of a portion of the outer liner 40 as seen from line III-III. The axial direction (denoted as "AD") is parallel to the engine centerline 20. Figure 1 The radial direction (denoted as "RD") extends into the page and is perpendicular to the axial direction AD, while the circumferential direction (denoted as "CD") is perpendicular to both the radial direction RD and the axial direction AD. The circumferential direction CD surrounds the engine centerline 20 and extends vertically along the page when oriented in two dimensions as shown in the figure.

[0044] As can be seen more clearly, the set of openings 57 in the outer liner 40 has a rectangular shape (denoted as "RS"). A second opening 57b is located between the first opening 57a and the third opening 57c. The first opening 57a includes a first geometric center 90a. The second opening 57b includes a second geometric center 90b and corresponds to the second miniature burner 34b. Figure 5 The third opening 57c includes a third geometric center 90c. The first opening 57a and the third opening 57c are oriented such that the first geometric center 90a and the third geometric center 90c are aligned in the circumferential direction CD and located at a first axial position A1. The second opening 57b is located at a second axial position A2, upstream of the first opening 57a and the third opening 57c. The first geometric center 90a and the second geometric center 90b are axially spaced apart from each other by an axial distance (denoted as "Ad"). The axial distance Ad is defined as an axial measurement between the first geometric center 90a and the second geometric center 90b.

[0045] This group of secondary burners 50 ( Figure 2 ) can be graded to align with the first, second, and third openings 57a, 57b, and 57c. The first and third miniature burners 34a and 34c ( Figure 2The secondary exhaust gas G2, exiting through the first and third openings 57a and 57c, is angled so that it flows downstream away from the corresponding first and third primary fuel injectors 30a and 30c. The second miniature burner 34b ( Figure 5 The secondary exhaust gas G2 discharged through the second opening 57b is angled so that it flows upstream toward the corresponding second primary fuel injector 30b.

[0046] Figure 4 Depicting along Figure 3 A cross-sectional view taken along line IV-IV shows a schematic diagram of the combustion section 14 as viewed in the first radial plane (denoted as "RP1"). A primary burner 32 extends between a dome wall 44 and a primary burner outlet 48. A first dome assembly 60a includes the dome wall 44 and houses a first primary fuel injector 30a. The first primary fuel injector 30a may be fluidly coupled to a first fuel inlet 62a via a first fuel passage 64a, which may be adapted to receive a primary fuel flow (denoted as "F1"). The first primary fuel injector 30a may terminate at a fuel outlet (also referred to herein as a first primary dome inlet 66a). In some embodiments, the first primary fuel injector 30a may include a first vortex 68a arranged circumferentially around the first primary dome inlet 66a. A first opening 57a is located downstream of the first primary dome inlet 66a.

[0047] The first primary igniter 61a is fluidly connected to the primary combustion chamber 46. The first secondary igniter 63a is fluidly connected to the first miniature burner 34a, and more specifically, to the first secondary combustion chamber 54a.

[0048] Compressed air passage 70 may surround primary burner 32 and is at least partially defined by housing 36. Compressed air (referred to as "C") may flow from compressor section 12 via compressed air passage 70. Figure 1 It provides air to combustion section 14. The primary dilution opening 72 connects the compressed air passage 70 and the primary combustion chamber 46.

[0049] A set of primary stage dilution openings 74a may be provided in the primary stage burner bushing 52a for connecting the compressed air passage 70 and the primary stage combustion chamber 54a. As a non-limiting example, when the primary burner 32 is a fuel-rich system, this set of primary stage dilution openings 74a is located downstream of the first miniature burner 34a to adjust the burner outlet temperature distribution and mode factor associated with the first miniature burner 34a and the primary burner 32.

[0050] Compressed air C can be split between the primary burner 32 and the group of secondary burners 50, such that the primary burner 32 receives 60% to 90% of the compressed air C from the compressor section 12, while the group of secondary burners 50 receives between 10% and 40% of the compressed air C.

[0051] The first miniature combustor 34a includes a first miniature dome assembly 80a, which includes a first miniature dome wall 82a and houses a first miniature fuel injector 84a. The first miniature fuel injector 84a may be fluidly coupled to a first-stage fuel passage 86a, which may be adapted to receive a secondary fuel flow (referred to herein as "F2"). The first miniature fuel injector 84a terminates at a secondary fuel outlet (also referred herein to as a first miniature dome inlet 88a leading to the first-stage combustion chamber 54a). In some embodiments, the first miniature fuel injector 84a may include a first low-swirling-number swirler 89a arranged circumferentially around the first miniature dome inlet 88a, i.e., having a number less than 1 and a low tangential velocity. Further contemplation is that the set of secondary combustors 50 may not include swirlers but may have non-swirling air passages.

[0052] The first primary dome inlet 66a defines the first primary centerline (denoted as "CLa"). The first secondary dome inlet 88a defines the first centerline CL1 extending toward the first primary burner outlet 58a. The first primary burner outlet 58a intersects the first centerline CL1 to define the first geometric center 90a of the first primary burner outlet 58a.

[0053] The total burner length (denoted as "L1") extends parallel to the first primary centerline CLa from the dome wall 44 to the primary burner outlet 48. The first burner length (denoted as "La") extends parallel to the first primary centerline CLa from the dome wall 44 to the first geometric center 90a. The first burner length La is 5% to 80% of the total burner length L1. In other words: 0.05L1 < La < 0.80L1.

[0054] As the secondary exhaust gas G2 is directed toward the primary burner outlet 48, the outlet temperature distribution and flame pattern factor for the primary burner 32 are improved. The secondary exhaust gas G2 modifies the existing temperature distribution and forces any unburned products from the first miniature burner 34a to be completely burned. Due to the increased turbulence generated by the colliding products, the mixing of the combustion products from this set of secondary burners 50 with the combustion products from the primary burner 32 helps to improve the temperature distribution within the primary combustion chamber 46.

[0055] Figure 5 Depicting along Figure 3A cross-sectional view taken by line VV shows the cross-section with respect to the first radial plane RP1 ( Figure 4 A schematic diagram of the combustion section 14 as viewed in a circumferentially spaced second radial plane (denoted as "RP2"). A primary burner 32 extends between a dome wall 44 and a primary burner outlet 48. A second dome assembly 60b includes the dome wall 44 and houses a second primary fuel injector 30b. The second primary fuel injector 30b may be fluidly coupled to a second fuel inlet 62b via a second fuel passage 64b, which may be adapted to receive a primary fuel flow (denoted as "F1"). The second primary fuel injector 30b may terminate at a fuel outlet, also referred to herein as a second primary dome inlet 66b. In some embodiments, the second primary fuel injector 30b may include a second vortex 68b arranged circumferentially around the second primary dome inlet 66b. A second opening 57b is located downstream of the second primary dome inlet 66b. The second opening 57b is fluidly coupled to a second miniature burner 34b to define a second primary burner outlet 58b.

[0056] The second primary igniter 61b is fluidly connected to the primary combustion chamber 46. The second stage igniter 63b is fluidly connected to the second miniature burner 34b, and more specifically, to the second stage combustion chamber 54b.

[0057] A set of secondary dilution openings 74b may be disposed in the secondary burner bushing 52b for connecting the compressed air passage 70 and the secondary combustion chamber 54b. As a non-limiting example, when the set of secondary dilution openings 74b is located in a position in front of the second miniature burner 34b, it is used to provide additional mixing associated with the second miniature burner 34b and the primary burner 32.

[0058] The second miniature combustor 34b includes a second miniature dome assembly 80b, which includes a second miniature dome wall 82b and houses a second miniature fuel injector 84b. The second miniature fuel injector 84b may be fluidly coupled to a second-stage fuel passage 86b, which may be adapted to receive a secondary fuel flow (referred to herein as "F2"). The second miniature fuel injector 84b terminates at a secondary fuel outlet, also referred herein as a second miniature dome inlet 88b leading to the second-stage combustion chamber 54b. In some embodiments, the second miniature fuel injector 84b may include a second low-swirling-number swirler 89b arranged circumferentially around the second miniature dome inlet 88b, i.e., having a number less than 1 and a low tangential velocity. Further contemplation is that the set of secondary combustors 50 may not include swirlers but may have non-swirling air passages.

[0059] The second primary dome inlet 66b defines the second primary centerline (denoted as "CLb"). The second secondary dome inlet 88b defines a second centerline CL2 extending toward the second stage burner outlet 58b. The second stage burner outlet 58b intersects the second centerline CL2 to define the second geometric center 90b of the second stage burner outlet 58b.

[0060] The length of the second burner (denoted as "Lb") extends parallel to the second primary centerline CLb from the dome wall 44 to the second geometric center 90b. The length of the second burner L2 is 5% to 80% of the total burner length L1. In other words: 0.05L < Lb < 0.80L1. From Figure 4 The first geometric center 90a and the second geometric center 90b are axially spaced apart by an axial distance (denoted as "Ad"). The axial distance Ad is 0% to + / -60% of the total burner length L1. In other words: -0.60L1 < Ad < 0.60L1.

[0061] From Figure 4 The first geometric center 90a and the first centerline CL1 are shown to help define the orientation angle β. The orientation angle β is the first miniature burner 34a ( Figure 4 The orientation difference between the second miniature burner 34b and the second miniature burner 34b. The orientation angle β can range from 0° to 120°.

[0062] When the secondary exhaust gas G2 is directed away from the primary combustor outlet 48, the primary exhaust gas G1 and the secondary exhaust gas G2 mix, which reduces the O2 level in the primary combustion chamber 46 and reduces NO. x Emissions. The amount of secondary exhaust gas G2 recirculated in the primary combustion chamber 46 can range from 0.1% to 100% to reduce NO. x emission.

[0063] During operation, refer to Figure 4 and Figure 5Compressed air C can be fed into the primary fuel injector 30 and mixed with the primary fuel stream F1 to define a primary fuel / air mixture (denoted as "FA1"). The first and second primary fuel injectors 30a, 30b, together with the first and second primary igniters 61a, 61b, define a primary combustion system with a primary flame. The first and second primary fuel injectors 30a, 30b can dispense a premixed or partially premixed primary fuel / air mixture FA1. Furthermore, the primary fuel stream F1 can be a diffusion fuel that does not contain an air mixture before entering the primary combustion chamber 46. The primary combustion system can be a rich system or a lean system. A rich combustion system includes a fuel / air ratio higher than the stoichiometric fuel / air ratio, while a lean combustion system includes a fuel / air ratio lower than the stoichiometric fuel / air ratio. The rich system for the primary burner 32 will generate higher temperatures within the primary combustion chamber 46, thereby providing flame stability for the entire combustion system. When combined with a lean system for the set of secondary burners 50, NO is reduced from the first and second secondary combustion chambers 54a, 54b. x .

[0064] Similarly, the primary burner 32 can be used to reduce NO from the primary combustion chamber 46. x The system is a lean-burn system, wherein the group of secondary burners 50 has a rich-burn system for providing flame stability to the primary burner 32 and the entire combustion system. Furthermore, both the primary burner 32 and the group of secondary burners 50 can be either rich-burn or lean-burn systems. Since both have lean-burn systems, NO... x Emissions are significantly reduced. However, at least one or more of the first and second primary fuel injectors 30a, 30b or the first and second miniature fuel injectors 84a, 84b will need to be fuel-rich to provide flame stability. Similarly, both the primary burner 32 and the group of secondary burners 50 can have a fuel-rich system, where NO in the system is reduced. x Lower NO production is achieved by using staged fuels and by reducing O2 levels in the primary burner 32 through the release of products from the secondary burners 50. x This is achieved through [the means].

[0065] Compressed air C can be fed into first and second miniature fuel injectors 84a, 84b and mixed with secondary fuel stream F2 to define a secondary fuel / air mixture (referred to as "FA2"). The first and second miniature fuel injectors 84a, 84b, together with first and second secondary igniters 63a, 63b, can define a miniature combustion system including a secondary flame that can be premixed, partially premixed, or diffused. The miniature combustion system can be a rich or lean system. The fuel supplied to the first and second primary fuel injectors 30a, 30b and the first and second miniature fuel injectors 84a, 84b can include injectable natural gas or more reactive fuels, such as H2 and a mixture of H2. In some embodiments, the turbine engine 10 ( Figure 1 The secondary burner 50 can be started on conventional fuel, wherein the secondary exhaust gas G2 propagates toward the primary combustion chamber 46, which can be fueled by conventional fuel or H2 fuel.

[0066] Fuel staging between the primary combustion chamber 46 and the secondary burners 50 reduces combustion zone 14. Figure 1 The fuel / air ratio in these stages helps to further reduce temperature and NO. x Emissions. In contrast, single-stage combustors will have a relatively high fuel / air ratio and higher temperature, which leads to higher NO emissions. x emission.

[0067] Figure 6A Is with Figure 2 Same and along Figure 3 The cross-sectional view taken by line AA, with housing 36 and most of the reference figures removed for clarity. The first-stage small burner 65 is arranged such that the secondary exhaust G2 is introduced in the first circumferential direction CD (as a non-limiting example, in the clockwise direction (denoted as "CW")).

[0068] Figure 6B It is along Figure 3 The cross-sectional view is taken from line BB, with housing 36 and most of the reference numerals removed for clarity. A second-stage miniature burner 67 is located upstream of the first-stage miniature burner 65. The second-stage miniature burner 67 is arranged such that the secondary exhaust gas G2 emitted from the second-stage miniature burner 67 is introduced in the same direction as the first circumferential direction CD (as a non-limiting example, in the clockwise direction CW). The second-stage miniature burner 67 includes at least a second miniature burner 34b and the remaining miniature burners 34 shown.

[0069] Figure 7A It comes from Figure 6AAn alternative version of the cross-sectional view shows a first-stage small burner 165 arranged such that the secondary exhaust gas G2 is introduced in the first direction (as a non-limiting example, in the clockwise direction CW).

[0070] Figure 7B It comes from Figure 6B An alternative version of the cross-sectional view shows a second-stage miniature combustor 167 located upstream of the first-stage miniature combustor 165. The second-stage miniature combustor 167 is arranged such that the secondary exhaust gas G2 emitted from the second-stage miniature combustor 167 is introduced in a second circumferential direction CD opposite to the first direction. As a non-limiting example, the second direction is counterclockwise (denoted as "CCW").

[0071] Although the first direction disclosed in this article is clockwise CW, it should be understood that the first direction can be counterclockwise CCW, and the second direction can be clockwise CW.

[0072] Figure 8 This is based on another aspect disclosed in this article. Figure 3 A schematic diagram of a variant of a portion of the outer liner 40. The outer liner 140 is similar to... Figure 3 Liner 40; therefore, similar parts will be identified by similarity numbers increased by 100, and it should be understood that, unless otherwise stated, the description of similar parts of liner 40 applies to liner 140.

[0073] A set of openings 157 may include a first opening 157a, a second opening 157b, and a third opening 157c. The first opening 157a includes a first geometric center 190a. The second opening 157b includes a second geometric center 190b, and the third opening 157c includes a third geometric center 190c. The first, second, and third openings 157a, 157b, and 157c are oriented such that the first, second, and third geometric centers 190a, 190b, and 190c are aligned in the circumferential direction CD and are all located at a third axial position A3. The third axial position A3 may be aligned with either the first axial position A1 or the second axial position A2. Figure 3 )same.

[0074] Figure 9 This is based on another aspect disclosed in this article. Figure 3 A schematic diagram of a variant of a portion of the outer liner 40. The outer liner 240 is similar to... Figure 3 Liner 40; therefore, similar parts will be identified by similarity numbers increased by 200, and it should be understood that, unless otherwise stated, the description of similar parts of liner 40 applies to liner 240.

[0075] A set of openings 257 may include a first opening 257a, a second opening 257b, and a third opening 257c. The first opening 257a includes a first geometric center 290a. The second opening 257b includes a second geometric center 290b, and the third opening 257c includes a third geometric center 290c. The first and third openings 257a and 257c are oriented such that the first and third geometric centers 290a and 290c are aligned in the circumferential direction CD and located at a fourth axial position A4. The second opening 257b is located downstream of the first and third openings 257a and 257c at a fifth axial position A5. The fourth axial position A4 may be adjacent to the first axial position A1, the second axial position A2, and the third axial position A5. Figure 2 ) or third axial position A3 ( Figure 8 The axial distance Ad is defined as the axial measurement between the fourth axial position A4 and the fifth axial position A5.

[0076] Figure 10 This is based on another aspect disclosed in this article. Figure 3 A schematic diagram of a variant of a portion of the outer liner 40. The outer liner 340 is similar to... Figure 3 Liner 40; therefore, similar parts will be identified by similarity numbers increased by 300, and it should be understood that, unless otherwise stated, the description of similar parts of liner 40 applies to liner 340.

[0077] A set of openings 357 may include a first opening 357a, a second opening 357b, a third opening 357c, and a fourth opening 357d. The first opening 357a includes a first geometric center 390a, the second opening 357b includes a second geometric center 390b, the third opening 357c includes a third geometric center 390c, and the fourth opening includes a fourth geometric center 390d. The first and fourth openings 357a and 357d are oriented such that the first and fourth geometric centers 390a and 390d are aligned in the circumferential direction CD and located at a sixth axial position A6. The second and third openings 357b and 357c are located upstream of the first and fourth openings 357a and 357d, at a seventh axial position A7, between the first and fourth openings 357a and 357d. The sixth axial position A6 may be aligned with the first axial position A1, the second axial position A2, and the third axial position A6. Figure 2 ), third axial position A3 ( Figure 8 ), fourth axial position A4 or fifth axial position A5 ( Figure 9 The axial distance Ad is defined as the axial measurement between the sixth axial position A6 and the seventh axial position A7.

[0078] A set of secondary burners (not visible) can be staged to align with the first, second, third, and fourth openings 357a, 357b, 357c, and 357d. The corresponding miniature burners (not visible) for the first and fourth openings 357a and 357d can be angled such that the secondary exhaust gas G2 discharged through the first and fourth openings 357a and 357d flows downstream away from the corresponding first and fourth primary fuel injectors 330a and 330d. The corresponding miniature burners (not visible) for the second and third openings 357b and 357c can be angled such that the secondary exhaust gas G2 discharged through the second and third openings 357b and 357c flows upstream towards the corresponding second and third primary fuel injectors 330b and 330c.

[0079] Figure 11 This is based on another aspect disclosed in this article. Figure 3 A schematic diagram of a variant of the outer liner 40. The outer liner 440 is similar to... Figure 3 Liner 40; therefore, similar parts will be identified by similar numbers increased by 400, and it should be understood that, unless otherwise stated, the description of similar parts of liner 40 applies to liner 440.

[0080] So far, all examples of the arrangement of openings in the liner have shown that each opening is axially aligned and located in the same circumferential position as the corresponding primary fuel injector. It is further envisioned that a set of openings 457 and corresponding primary fuel injectors 430 could be axially staggered and located in different circumferential positions.

[0081] A set of openings 457 may include a first opening 457a, a second opening 457b, a third opening 457c, and a fourth opening 457d. The first opening 457a includes a first geometric center 490a and is located at a first circumferential position C1. The second opening 457b includes a second geometric center 490b and is located at a second circumferential position C2. The third opening 457c includes a third geometric center 490c and is located at a third circumferential position C3. The fourth opening 457d includes a fourth geometric center 490d and is located at a fourth circumferential position C4. All the first, second, third, and fourth openings 457a, 457b, 457c, and 457d may be located at an eighth axial position A8.

[0082] The primary fuel injector 430 may include a first primary fuel injector 430a, a second primary fuel injector 430b, and a third primary fuel injector 430c. The first primary fuel injector 430a is located at a fifth circumferential position C5 between the first and second circumferential positions C1 and C2. The second primary fuel injector 430b is located at a sixth circumferential position C6 between the second and third circumferential positions C2 and C3. The third primary fuel injector 430c is located at a seventh circumferential position C7 between the third and fourth circumferential positions C3 and C4.

[0083] The eighth axial position A8 can be the same as the first axial position A1. Figure 2 ), second axial position A2 ( Figure 2 ), third axial position A3 ( Figure 8 ), fourth axial position A4 ( Figure 9 ), fifth axial position A5 ( Figure 9 ), sixth axial position A6 ( Figure 10 ) or seventh axial position A7 ( Figure 10 )same.

[0084] A set of secondary burners (not visible) can be staged to align with the first, second, third, and fourth openings 457a, 457b, 457c, and 457d. The corresponding miniature burners (not visible) for the first and fourth openings 457a and 457d can be angled such that the secondary exhaust gas G2 discharged through the first and fourth openings 457a and 457d flows downstream away from the corresponding first and fourth primary fuel injectors 430a and 430d. The corresponding miniature burners (not visible) for the second and third openings 457b and 457c can be angled such that the secondary exhaust gas G2 discharged through the second and third openings 457b and 457c flows upstream towards the corresponding second and third primary fuel injectors 430b and 430c.

[0085] Figure 12 This is based on another aspect disclosed in this article. Figure 3 A schematic diagram of a variant of a portion of the outer liner 40. The outer liner 540 is similar to... Figure 3 Liner 40; therefore, similar parts will be identified by similarity numbers increased by 500, and it should be understood that, unless otherwise stated, the description of similar parts of liner 40 applies to liner 540.

[0086] A set of openings 557 may include a first opening 557a, a second opening 557b, and a third opening 557c. The first opening 557a includes a first geometric center 590a, the second opening 557b includes a second geometric center 590b, and the third opening 557c includes a third geometric center 590c. The first and third openings 557a and 557c are oriented such that the first and third geometric centers 590a and 590c are aligned in the circumferential direction CD and located at a ninth axial position A9. The second opening 557b is located downstream of the first and third openings 557a and 557c, at a tenth axial position A10, between the first and third openings 557a and 557c. The ninth axial position A9 may be adjacent to the first axial position A10. Figure 2 ), second axial position A2 ( Figure 2 ), third axial position A3 ( Figure 8 ), fourth axial position A4 ( Figure 9 ), fifth axial position A5 ( Figure 9 ), sixth axial position A6 ( Figure 10 ), seventh axial position A7 ( Figure 10 ) or the eighth axial position A8 ( Figure 11 The axial distance Ad is defined as the axial measurement between the ninth axial position A9 and the tenth axial position A10.

[0087] Furthermore, the first, second, and third openings 557a, 557b, and 557c rotate from the axial direction AD toward the circumferential direction CD to define an opening angle (denoted as "α"). In one aspect, the first and third openings 557a and 557c rotate clockwise (denoted as "CW"), and the second opening 557b rotates counterclockwise (denoted as "CCW").

[0088] A set of secondary burners (not visible) can be staged to align with the first, second, and third openings 557a, 557b, and 557c. The corresponding miniature burners (not visible) for the first and third openings 557a and 557c can be angled such that the secondary exhaust gas G2 exiting through the first and second openings 557a and 557c flows upstream at an opening angle α, generally toward the corresponding first and third primary fuel injectors 530a and 530c. The corresponding miniature burner (not visible) for the second opening 557b can be angled such that the secondary exhaust gas G2 exiting through the second opening 557b flows downstream at an opening angle α, generally away from the corresponding second primary fuel injector 530b.

[0089] Figure 13 This is based on another aspect disclosed in this article. Figure 3 A schematic diagram of a variant of a portion of the outer liner 40. The outer liner 640 is similar to... Figure 3The outer liner 40; therefore, similar portions will be identified by similarity numerals increased by 600, and it should be understood that, unless otherwise stated, the description of similar portions of the outer liner 40 applies to the outer liner 640. The outer liner 640 includes a set of openings 657, including a first opening 657a, a second opening 657b, and a third opening 657c, which are oriented such that the opening angle α is relative to... Figure 8 The multiple openings 157a, 157b, and 157c shown are at 90-degree angles. In other words, the opening angle α can be in the range of -90 degrees to 90 degrees.

[0090] Figure 14 This is based on another aspect disclosed in this article. Figure 3 A schematic diagram of a variant of a portion of the outer liner 40. The outer liner 740 is similar to... Figure 3 The outer liner 40; therefore, similar portions will be identified by similar numbers increasing by 700, and it should be understood that, unless otherwise stated, the description of similar portions of the outer liner 40 applies to the outer liner 740. The outer liner 740 includes a plurality of openings 757a, 757b, 757c having an oval shape (referred to as "OS").

[0091] Any combination of the position and orientation of the openings 57, 57a, 57b, 57c, 157a, 157b, 157c, 257a, 257b, 257c, 357a, 357b, 357c, 357d, 457a, 457b, 457c, 457d, 557a, 557b, 557c, 657a, 657b, 657c, 757a, 757b, 757c is conceivable. Furthermore, although three or four openings are shown, it should be understood that any number of openings and a suitable corresponding number of miniature burners 34, 34a, 34b are conceivable. The position, orientation, number, and shape can be adjusted to achieve adequate mixing between the two exhausts G1, G2. It is also conceivable that any opening described herein could be square or circular. For rectangular or oval / elliptical shapes, the shape can extend along the main burner axis, or be transverse or inclined relative to the main burner axis.

[0092] A method for controlling nitrogen oxides present in the combustion section 14 described herein includes generating primary exhaust gas G1 in a primary combustion chamber 46 and generating secondary exhaust gas G2 in the group of secondary combustors 50 including secondary combustion chambers 54a, 54b. The method also includes injecting secondary exhaust gas G2 into the primary combustion chamber 46. The method further includes introducing secondary exhaust gas G2 in an upstream direction toward primary fuel injectors 30a, 30b, 30c, 130a, 130b, 130c, 230a, 230b, 230c, 330a, 330b, 330c, 330d, 430a, 430b, 430c, 530a, 530b, 530c, 630a, 630b, 630c, 730a, 730b, 730c. 2, and introduce secondary exhaust gas G2 in a downstream direction away from the primary fuel injectors 30a, 30b, 30c, 130a, 130b, 130c, 230a, 230b, 230c, 330a, 330b, 330c, 330d, 430a, 430b, 430c, 530a, 530b, 530c, 630a, 630b, 630c, 730a, 730b, 730c.

[0093] The benefits associated with the combination of the secondary burners and primary burners described herein, and the associated methods, are that NO reduction is achieved even in demanding cycles with higher operating air pressures, higher temperatures, higher fuel / air ratios, and heated fuels. x Emissions. Typically, a higher fuel / air ratio within the combustion system leads to higher flame temperatures, which in turn result in higher NOx levels. x By having two combustion chambers within the combustion system, fuel can be split between these chambers, thereby reducing the fuel / air ratio in each chamber, resulting in lower temperatures and thus lower NO emissions. x Emissions. By directing combustion products from secondary combustion to the primary combustion chamber, the O2 level in the primary combustion chamber can be reduced, thereby further reducing NO. x Emissions. The combustion zone described in this article can be operated using 100% H2 fuel.

[0094] Additionally, directing some stages forward and others backward toward the outlet helps burn soot from the main stage. Both stages achieve lower main burner zone temperatures due to fuel staging and reduced flame temperature. The discrete, smaller stages tilted toward the main burner disrupt the main burner flow, thereby reducing O2 levels and thus NO. x Emissions. A smaller, rear-facing stage can help control the outlet temperature distribution / pattern.

[0095] Although described in the context of a turbocharged engine, it should be understood that the combustor described herein can be used for engines with NO emissions.x Any engine with a combustor. It should be understood that the applications of the disclosed aspects discussed herein can also be applied to engines with propeller sections or fan and supercharger sections, as well as turbojet engines and turbine engines.

[0096] Within the scope not described herein, different features and structures of various embodiments may be combined or substituted for each other as needed. The fact that a feature is not shown in all embodiments does not mean that it cannot be shown so, but rather that it is done for the sake of brevity. Therefore, various features of different embodiments may be mixed and matched as needed to form new embodiments, regardless of whether the new embodiments are explicitly described. All combinations or permutations of the features described herein are covered by this disclosure.

[0097] This written description uses examples to illustrate aspects of the disclosure described herein, including best practices, and also enables any person skilled in the art to practice aspects of this disclosure, including making and using any apparatus or system and methods of making any combinations. The patentable scope of aspects of this disclosure is defined by the claims, and may include other examples that would occur to a person skilled in the art. Such other examples are intended to fall within the scope of the claims if they have structural elements that are not indistinguishable from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims.

[0098] Further details are provided by the following topics:

[0099] A combustion section for a turbine engine, the combustion section comprising: a primary combustor bushing including an inner liner and an outer liner annular about an engine centerline, wherein the outer liner defines a set of openings including at least a first opening and a second opening; a dome wall extending between the inner liner and the outer liner; a set of primary dome inlets located in the dome wall and circumferentially arranged about the engine centerline, the set of primary dome inlets being upstream of the set of openings and including at least a first primary dome inlet and a second primary dome inlet; and a primary combustor having a primary combustion chamber defined at least partially by the inner liner, the outer liner, and the dome wall, and extending between the dome wall and a primary combustor outlet. The primary combustion chamber is defined by a set of secondary burners fluidly connected at a set of openings, the set of secondary burners comprising at least: a first miniature burner oriented away from the first primary dome inlet and having a first miniature dome inlet defining a first centerline extending away from the first primary dome inlet through the first opening; and a second miniature burner oriented toward the second primary dome inlet and having a second miniature dome inlet defining a second centerline extending toward the second primary dome inlet through the second opening; wherein the orientation difference between the first centerline and the second centerline defines an orientation angle ranging from 0° to 120°.

[0100] According to any of the preceding clauses, the combustion section wherein the first miniature burner and the second miniature burner are arranged to exhaust gas in the same circumferential direction.

[0101] According to any of the preceding clauses, the combustion section wherein the first miniature burner and the second miniature burner are arranged to exhaust gases in opposite circumferential directions.

[0102] According to any of the preceding clauses, the combustion zone, wherein the set of openings is a plurality of openings arranged circumferentially around the centerline of the engine.

[0103] According to any of the preceding clauses, the combustion section wherein the set of primary dome inlets and the set of openings are located at the same circumferential position.

[0104] According to any of the preceding clauses, the combustion zone, wherein the first opening is located at the same axial position as the second opening.

[0105] According to any of the preceding clauses, the combustion section wherein the first opening is located at a different axial position than the second opening.

[0106] The combustion zone according to any of the foregoing clauses further includes a third opening located at the same axial position as the second opening.

[0107] The combustion zone according to any of the foregoing clauses further includes a fourth opening located at the same axial position as the first opening, wherein the second opening and the third opening are located between the first opening and the fourth opening.

[0108] According to any of the preceding clauses, the combustion section wherein the set of primary dome inlets and the set of openings are located at different circumferential positions.

[0109] According to any of the preceding clauses, the combustion zone, wherein the first opening is located at the same axial position as the second opening.

[0110] According to any of the preceding clauses, the combustion zone wherein the set of openings rotates from the axial direction toward the circumferential direction to define the opening angle.

[0111] According to any of the preceding clauses, the combustion section wherein the first opening rotates clockwise and the second opening rotates counterclockwise.

[0112] According to any of the preceding clauses, the combustion section wherein the first opening is located at a different axial position than the second opening.

[0113] According to any of the preceding clauses, the combustion zone, wherein the opening angle ranges from -90 degrees to 90 degrees.

[0114] According to any of the preceding clauses, the combustion zone wherein the set of openings is rectangular in shape.

[0115] According to any of the preceding clauses, the combustion section wherein the set of openings is oval in shape.

[0116] According to any of the preceding clauses, the combustion zone, wherein the first opening defines a first geometric center, and the second opening defines a second geometric center spaced axially from the first geometric center.

[0117] According to any of the preceding clauses, the combustion section, wherein the length of the first burner extends from the dome wall to the first geometric center, and the length of the second burner extends from the dome wall to the second geometric center, wherein the lengths of the first burner and the second burner are both within the range of 5% to 80% of the total burner length.

[0118] According to any of the preceding clauses, the combustion zone, wherein the axial distance ranges from -60% to 60% of the total burner length.

[0119] A method for controlling nitrogen oxides includes: generating primary exhaust gas in a primary combustion chamber and generating secondary exhaust gas in a set of secondary burners, each secondary burner including a secondary combustion chamber; injecting the primary exhaust gas from a first miniature burner into a main combustion zone of the primary combustion chamber along a first centerline in a first direction; and injecting the secondary exhaust gas from a second miniature burner into the main combustion zone of the primary combustion chamber along a second centerline oriented in a different orientation in a second direction.

[0120] The method described according to any of the foregoing clauses further includes introducing the first-stage exhaust and the second-stage exhaust in the same circumferential direction.

[0121] The method described according to any of the foregoing clauses further includes introducing the first-stage exhaust and the second-stage exhaust in opposite circumferential directions.

Claims

1. A combustion section for a turbine engine characterized by, The combustion zone includes: A primary burner bushing, the primary burner bushing comprising an inner bushing and an outer bushing arranged in a ring; A dome wall extending between the inner liner and the outer liner; A set of primary dome inlets, the set of primary dome inlets being located within the dome wall; A primary burner having a primary combustion chamber, the primary combustion chamber being at least partially defined by the inner liner, the outer liner, and the dome wall, and defining a primary centerline; and A set of secondary burners, the set of secondary burners being fluidly connected to the primary combustion chamber at the liner, the set of secondary burners comprising at least: A first miniature burner, the first miniature burner being disposed within the outer liner; and A second miniature burner is disposed in the outer liner and spaced axially from the first miniature burner relative to the primary centerline; The first and second miniature burners produce combustion products, which are injected into the primary combustion chamber.

2. The combustion zone according to claim 1, characterized in that, It further includes a set of openings disposed in the outer liner, wherein the set of openings includes at least a first opening and a second opening.

3. The combustion zone according to claim 2, characterized in that, in, The first miniature burner is disposed at the first opening, and the second miniature burner is disposed at the second opening.

4. The combustion zone according to claim 2, characterized in that, in, The first opening is positioned in front of the second opening relative to the primary centerline.

5. The combustion zone according to claim 1, characterized in that, in, The first miniature burner defines a first geometric center, and the second miniature burner defines a second geometric center, wherein the first geometric center and the second geometric center are spaced apart relative to the primary centerline.

6. The combustion zone according to claim 5, characterized in that, in, The first geometric center is axially spaced from the second miniature burner.

7. The combustion zone according to claim 6, characterized in that, in, The second geometric center is axially spaced from the first miniature burner.

8. The combustion zone according to claim 5, characterized in that, in, The first geometric center overlaps with the second miniature burner relative to the primary centerline.

9. The combustion zone according to claim 8, characterized in that, in, The second geometric center overlaps with the first miniature burner relative to the primary centerline.

10. The combustion zone according to claim 1, characterized in that, in, The first miniature burner is tilted toward the primary burner, and the second miniature burner is tilted away from the primary burner.

11. The combustion zone according to claim 1, characterized in that, in, The first miniature burner is one of a group of first miniature burners arranged in a ring around the outer liner.

12. The combustion zone according to claim 11, characterized in that, in, The second miniature burner is one of a group of second miniature burners arranged in a ring around the outer liner.

13. The combustion zone according to claim 12, characterized in that, in, At least two of the first miniature burners in the group of first miniature burners are arranged between adjacent second miniature burners in the group of second miniature burners circumferentially defined around the primary centerline.

14. A combustion section for a turbine engine, characterized in that, The combustion zone includes: A primary burner bushing, the primary burner bushing comprising an inner bushing and an outer bushing arranged in a ring around an engine centerline, the engine centerline defining an axial direction along the engine centerline, defining a radial direction extending perpendicularly from the engine centerline, and defining a circumferential direction extending circumferentially around the engine centerline. A dome wall extending between the inner liner and the outer liner; A set of primary dome inlets, the set of primary dome inlets being located in the dome wall and arranged circumferentially around the engine centerline; A primary burner having a primary combustion chamber defined at least partially by the inner liner, the outer liner, and the dome wall; and A secondary burner is fluidly connected to the primary combustion chamber at the liner, wherein the secondary burner is configured as a set of secondary burners including at least a first miniature burner and a second miniature burner, wherein the first miniature burner and the second miniature burner are arranged to discharge combustion products in the same circumferential direction; The secondary burner rotates along the liner with an opening angle relative to the axial direction, such that the combustion products generated by the secondary burner are injected circumferentially around the liner in a manner corresponding to the opening angle into the primary combustion chamber.

15. The combustion zone according to claim 14, characterized in that, in, The first miniature burner is oriented in a clockwise direction defined by the opening angle.

16. The combustion zone according to claim 15, characterized in that, in, The second miniature burner is oriented in a counterclockwise direction defined by the opening angle.

17. The combustion zone according to claim 16, characterized in that, in, The opening angle is -90 degrees or 90 degrees, thereby aligning the secondary burner with the circumferential direction.

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