Combustor comprising heat shield for turbine engine

Abstract

A combustor of a turbine engine combusts fuel and air. The combustor includes a dome and a heat shield secured to the dome. The heat shield is unconstrained relative to the dome to allow relative thermal expansion and contraction in a radial direction. The heat shield interior is generally annular, disposed about the dome bore longitudinal centerline axis, smaller in diameter than the dome interior, and assembled inside the dome interior. A plurality of pin assemblies secure the heat shield to the dome. Each pin assembly includes a fastener with a pin end that is assembled in a clearance fit into a bore inside the heat shield. The fastener is secured inside the dome and the pin end slides in the bore of the heat shield during relative thermal expansion and contraction between the dome and the heat shield.

Description

Technical Field

[0001] This disclosure generally relates to a combustor that includes a heat shield for a turbine engine. Background Technology

[0002] For example, turbine engines used in aircraft typically include a fan and a turbocharger that are in fluid communication with each other. Within the turbocharger, the combustor includes one or more fuel nozzle mixer assemblies arranged at the upstream end for introducing and mixing fuel and air for combustion in the combustion chamber. A heat shield at the downstream end of the fuel nozzle mixer assembly protects the assembly from the heat of combustion. The heat shield can be made of composite materials and can be mounted on a metal structural component, such as a dome. Attached Figure Description

[0003] Features and advantages will become apparent from the following more specific description of various exemplary embodiments, as illustrated in the accompanying drawings, wherein the same reference numerals generally denote the same, functionally similar and / or structurally similar elements.

[0004] Figure 1 This is a schematic cross-sectional view of a turbine engine taken along the longitudinal centerline axis of the turbine engine according to the present disclosure.

[0005] Figure 2 It is a schematic cross-sectional view of the burner taken along the longitudinal centerline axis of the burner according to this disclosure.

[0006] Figure 3A This is a schematic cross-sectional view of the heat shield mounting assembly taken along the longitudinal centerline of the burner according to this disclosure.

[0007] Figure 3B This is a schematic cross-sectional view of the heat shield mounting assembly, taken orthogonally to the longitudinal centerline of the burner, according to this disclosure.

[0008] Figure 4 This is a schematic cross-sectional view of the heat shield mounting assembly taken along the longitudinal centerline of the burner according to this disclosure.

[0009] Figure 5 This is a schematic cross-sectional view of the heat shield mounting assembly taken along the longitudinal centerline of the burner according to this disclosure.

[0010] Figure 6 This is a schematic cross-sectional view of the heat shield mounting assembly taken along the longitudinal centerline of the burner according to this disclosure. Detailed Implementation

[0011] The features, advantages, and embodiments of the present invention will be set forth or apparent from the following detailed description, drawings, and claims. Furthermore, the following detailed description is exemplary and intended to provide further explanation without limiting the scope of the claimed disclosure.

[0012] Various embodiments of this disclosure are discussed in detail below. Although specific embodiments are discussed, they are for illustrative purposes only. Those skilled in the art will recognize that other components and configurations can be used without departing from this disclosure.

[0013] The terms “first,” “second,” and “third” may be used interchangeably in this document to distinguish one component from another and are not intended to indicate the location or importance of the individual components.

[0014] The terms "upstream" and "downstream" refer to the relative directions of fluid flow within a fluid channel. For example, "upstream" refers to the direction from which fluid flows, and "downstream" refers to the direction from which fluid flows.

[0015] The terms "forward" and "rearward" refer to the relative positions within a turbine engine or vehicle, and to the normal operating posture of the turbine engine or vehicle. For example, in the case of a turbine engine, "forward" refers to the position closer to the propeller or fan, while "rearward" refers to the position further away from the propeller or fan.

[0016] As used herein, when used in conjunction with compressors, combustors, turbines, shafts, fans, or turbine engine components, each of the terms “low,” “medium” (or “medium”), and “high,” or their respective comparatives (e.g., “lower” and “higher,” as applicable), refers to a relative pressure, relative speed, relative temperature, or relative power output within the engine, unless otherwise specified. For example, a “low power” setting defines an engine or combustor configured to operate at a power output lower than the “high power” setting of the engine or combustor, and a “medium power” setting defines an engine or combustor configured to operate at a power output higher than the “low power” setting but lower than the “high power” setting. The terms “low,” “medium” (or “medium”), or “high” in the foregoing terms may additionally or alternatively be understood as relative to a minimum permissible speed, pressure, or temperature, or relative to the minimum or maximum permissible speed, pressure, or temperature of the engine during normal, expected, steady-state, etc., operation. Turbine engine duty cycles include, for example, low power operation, medium power operation, and high power operation. Low power operation includes, for example, engine start, idling, coasting, and approach. Medium-power operations include, for example, cruise. High-power operations include, for example, takeoff and climb.

[0017] Unless otherwise specified herein, the terms “connection,” “attachment,” “link,” etc., refer to both direct connection, attachment, or linking, and indirect connection, attachment, or linking through one or more intermediate components or features.

[0018] Unless the context clearly indicates otherwise, the singular forms “a,” “one,” and “the” include plural references.

[0019] The approximate language used throughout this specification and claims is intended to modify any quantitative expression that may vary but does not alter its underlying function. Therefore, values ​​modified by one or more terms (such as “about,” “approximate,” “usually,” and “substantially”) are not limited to specified exact 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 a component or system or manufacture a component or system. For example, approximate language may refer to a range of one percent, two percent, four percent, ten percent, fifteen percent, or twenty percent of a single value, a range of values, or the endpoints of a defined range of values.

[0020] As used herein, the terms “air” and “oxidizer” can be used interchangeably when used together for combustion.

[0021] As used herein, the term "composite material" refers to a material having two or more constituent materials. A composite material can be a combination of at least two or more metals, nonmetals, or metallic and nonmetallic elements or materials. Examples of composite materials can be, but are not limited to, polymer-based composites (PMCs), ceramic-based composites (CMCs), or metal-based composites (MMCs). Composite materials can be formed from a matrix material and reinforcing elements, such as fibers (referred to herein as reinforcing fibers).

[0022] As used herein, CMC refers to a class of materials having reinforcing fibers within a ceramic matrix. Typically, the reinforcing fibers provide structural integrity to the ceramic matrix. Some examples of reinforcing fibers may include, but are not limited to, non-oxide silicon-based materials (e.g., silicon carbide, silicon nitride, or mixtures thereof), non-oxide carbon-based materials (e.g., carbon), oxide ceramics (e.g., silicon carbide, silicon oxynitride, alumina (Al₂O₃), silicon dioxide (SiO₂), aluminosilicates such as mullite, or mixtures thereof), or mixtures thereof.

[0023] Examples of ceramic matrix materials may include, but are not limited to, non-oxide silicon-based materials (e.g., silicon carbide, silicon nitride, or mixtures thereof), oxide ceramics (e.g., silicon oxycarbide, silicon oxynitride, alumina (Al₂O₃), silicon dioxide (SiO₂), aluminum silicate, or mixtures thereof), or mixtures thereof. Optionally, ceramic particles (e.g., oxides of Si, Al, Zr, Y, and combinations thereof) and inorganic fillers (e.g., pyrophyllite, wollastonite, mica, talc, kyanite, and montmorillonite) may also be included in the ceramic matrix.

[0024] Generally, a specific CMC can be identified by its combination or fiber / matrix type. For example, C / SiC is used for carbon fiber reinforced silicon carbide, SiC / SiC for silicon carbide fiber reinforced silicon carbide, SiC / SiN for silicon carbide fiber reinforced silicon nitride, and SiC / SiC-SiN for silicon carbide fiber reinforced silicon carbide / silicon nitride matrix mixtures, etc. In other examples, a CMC can consist of a matrix and reinforcing fibers, with the reinforcing fibers including oxide-based materials such as alumina (Al₂O₃), silicon dioxide (SiO₂), aluminosilicates, and mixtures thereof. Aluminosilicates can include crystalline materials such as mullite (3Al₂O₃·2SiO₂) and glassy aluminosilicates.

[0025] In some non-limiting examples, reinforcing fibers may be bundled (e.g., forming fiber bundles) and / or coated before being incorporated into the matrix. The fiber bundles may be impregnated with a slurry composition before or after forming the preform. The preform may then undergo heat treatment and subsequent chemical treatment to obtain a part formed from a CMC material having the desired chemical composition. For example, the preform may undergo curing or burn-out, resulting in a high carbon residue in the preform, followed by melt infiltration with silicon, or curing or pyrolysis, resulting in a silicon carbide matrix in the preform, followed by chemical vapor infiltration with silicon carbide. Additional steps may be taken before or after chemical vapor infiltration to enhance the densification of the preform, i.e., by injecting a liquid resin or polymer into the preform followed by a heat treatment step to fill the voids with silicon carbide. The CMC material used herein can be formed using any known or later developed method, including but not limited to melt infiltration, chemical vapor infiltration, polymer impregnation pyrolysis (PIP), or any combination thereof.

[0026] As used herein, the term "metal" refers to materials that include metals, such as, but not limited to, titanium, iron, aluminum, stainless steel, and nickel alloys. A metallic material or alloy can be a combination of at least two or more elements or materials, at least one of which is a metal.

[0027] A known burner includes a fuel nozzle mixer assembly with a pilot swirler comprising a venturi tube. The pilot swirler injects a fuel-air mixture into the venturi tube and then into the combustion chamber, where the fuel-air mixture is burned. At the outlet end of the venturi tube, a heat shield is typically provided to protect the fuel nozzle mixer assembly. A conventional heat shield comprises a heat shield flange, which is typically aligned perpendicular to the centerline of the fuel nozzle, with a square-tipped outer edge. As the fuel-air mixture exiting the venturi tube burns, the flow path outside the venturi tube creates a hot zone on the rear surface of the heat shield. Cooling air for cooling the heat shield is supplied through the fuel nozzle mixer assembly and discharged through channels therein.

[0028] This disclosure addresses the aforementioned problems by providing a heat shield and fuel nozzle center body with a rear-end geometry that further directs cooling air in a more axial direction, thereby reducing the gas temperature in the hot zone or offsetting the hot zone rearward. According to this disclosure, the heat shield flange may include a forward-facing edge or include angled heat shield bypass holes. Alternatively, the fuel nozzle center body may include one or more additional center body edge bypass holes, a concave rear surface, or an edge rear surface with rounded corners. By offsetting the hot zone further rearward within the combustor, the heat shield is exposed to less heat, providing better durability than conventional heat shields by reducing the likelihood of material degradation due to prolonged proximity to the hot zone.

[0029] like Figure 1 As used in the following description, the terms "axial" and "axially" refer to the direction and orientation extending substantially parallel to the longitudinal centerline axis of the turbine engine. Furthermore, the terms "radial" and "radially" refer to the direction and orientation extending substantially perpendicular to the longitudinal centerline axis of the turbine engine. Additionally, as used herein, the terms "circumferential" and "circumferentially" refer to the direction and orientation extending in an arc around the longitudinal centerline axis of the turbine engine.

[0030] Now refer to the attached diagram, Figure 1 This is a schematic cross-sectional view of the turbine engine 10 taken along the longitudinal centerline axis 12 of the turbine engine 10 according to an embodiment of the present disclosure. Figure 1 As shown, the turbine engine 10 defines an axial direction A (extending parallel to the longitudinal centerline axis 12 provided as a reference), a radial direction R orthogonal to the axial direction A, and a circumferential direction C around the longitudinal centerline axis 12. Typically, the turbine engine 10 includes a fan section 14 and a turbocharger engine 16 disposed downstream of the fan section 14.

[0031] The turbocharged engine 16 comprises a compressor section 21, a combustor 26, and a turbine section 27 in a series flow relationship. The turbocharged engine 16 is substantially enclosed within a housing 18, which is substantially tubular and defines an annular inlet 20. Figure 1 As schematically shown, compressor section 21 includes a turbocharger or low-pressure (LP) compressor 22, downstream of which is a high-pressure (HP) compressor 24. Combustor 26 is located downstream of compressor section 21. Turbine section 27 is located downstream of combustor 26 and includes a high-pressure (HP) turbine 28, downstream of which is a low-pressure (LP) turbine 30. Turbocharged engine 16 also includes an injection exhaust nozzle section 32, a high-pressure (HP) shaft 34 or spool, and a low-pressure (LP) shaft 36 located downstream of turbine section 27. HP shaft 34 drivesly connects HP turbine 28 to HP compressor 24. HP turbine 28 and HP compressor 24 rotate synchronously via HP shaft 34. LP shaft 36 drivesly connects LP turbine 30 to LP compressor 22. LP turbine 30 and LP compressor 22 rotate synchronously via LP shaft 36. Compressor section 21, combustor 26, turbine section 27, and injection exhaust nozzle section 32 together define the core airflow path.

[0032] for Figure 1 In the illustrated embodiment, fan section 14 includes a fan 38 (e.g., a variable pitch fan) having a plurality of fan blades 40 spaced apart and coupled to disk 42. Figure 1 As shown, fan blades 40 typically extend outward from disk 42 along the radial direction R. In the case of a variable pitch fan, multiple fan blades 40 are operably coupled to an actuating member 44 by means of the fan blades 40, allowing them to rotate relative to disk 42 about the pitch axis P. The actuating member 44 is configured to collectively and uniformly change the pitch of the fan blades 40. The fan blades 40, disk 42, and actuating member 44 can rotate together about the longitudinal centerline axis 12 via a fan shaft 45, which is powered by a power gearbox (also called gearbox assembly 46) through a LP shaft 36. Thus, fan 38 is driven and powered by a turbocharged engine 16, which is an indirect drive engine. Gearbox assembly 46 is located in... Figure 1 The diagram is schematically shown. Gearbox assembly 46 is a reduction gearbox assembly used to regulate the speed of fan shaft 45 when power is transmitted from LP shaft 36 to fan shaft 45, thereby regulating the speed of fan 38 relative to LP shaft 36.

[0033] Still referencing Figure 1In an exemplary embodiment, the disk 42 is covered by a fan hub 48 having an aerodynamic profile to facilitate airflow through a plurality of fan blades 40. Furthermore, the fan section 14 includes an annular fan housing or nacelle 50 circumferentially surrounding at least a portion of the fan 38 and the turbocharged engine 16. The nacelle 50 is supported relative to the turbocharged engine 16 by a plurality of outlet guide vanes 52 circumferentially spaced around the nacelle 50 and the turbocharged engine 16. Additionally, a downstream section 54 of the nacelle 50 extends outside the turbocharged engine 16 and, together with the housing 18, defines a bypass airflow passage 56 therebetween.

[0034] During operation of the turbine engine 10, a certain amount of air 58 enters the turbine engine 10 through the nacelle 50 or the inlet 60 of the fan section 14. As the air 58 passes through the fan blades 40, a first portion of the air (also called bypass air 62) is directed into the bypass airflow passage 56, and a second portion of the air (called core air 64) is directed into the upstream section of the core air flow path through the annular inlet 20 of the LP compressor 22. The ratio between bypass air 62 and core air 64 is commonly referred to as the bypass ratio. The pressure of the core air 64 then increases, producing compressed air 65. The compressed air 65 is directed through the HP compressor 24 and into the combustor 26, where it is mixed with fuel and ignited to produce combustion gases 66.

[0035] Combustion gas 66 is guided into and expanded by the HP turbine 28, where a portion of the thermal or kinetic energy is extracted via one or more stages of HP turbine stator blades 68 and HP turbine rotor blades 70 connected to the HP shaft 34. This causes the HP shaft 34 to rotate, thereby supporting the operation of the HP compressor 24 (self-sustaining cycle). Thus, the combustion gas 66 performs work on the HP turbine 28. The combustion gas 66 is then guided into and expanded by the LP turbine 30. Here, a second portion of the thermal or kinetic energy is extracted from the combustion gas 66 via one or more stages of LP turbine stator blades 72 and LP turbine rotor blades 74 connected to the LP shaft 36. This causes the LP shaft 36 to rotate, thereby supporting the operation of the LP compressor 22 (self-sustaining cycle) and the rotation of the fan 38 via the gearbox assembly 46. Thus, the combustion gas 66 performs work on the LP turbine 30.

[0036] Combustion gas 66 is then directed through the injector exhaust nozzle section 32 of the turbocharged engine 16 to provide propulsive thrust. Simultaneously, bypass air 62, passing through bypass airflow passage 56 before exiting from the fan nozzle exhaust section 76 of the turbocharged engine 10, also provides propulsive thrust. The HP turbine 28, LP turbine 30, and injector exhaust nozzle section 32 at least partially define a hot gas path 78 for directing combustion gas 66 through the turbocharged engine 16.

[0037] The turbine engine 10 includes a fuel system 79 that supplies fuel to a combustor 26. Fuel is mixed with compressed air 65 from an HP compressor 24 and ignited in the combustor 26 to produce combustion gases 66. The fuel system may include a fuel tank or fuel supply device for storing fuel therein, a fuel supply line, and a fuel injector. Fuel is supplied from the fuel tank along the fuel supply line to the fuel injector, which introduces fuel into the combustor 26. The fuel system may include one or more flow control devices or valves along the fuel supply line for controlling the amount of fuel supplied to the combustor 26. The fuel injector may be located at the front end of the combustor 26. Therefore, fuel supplied along the fuel supply line is provided at the front end of the combustor 26.

[0038] Figure 1 The turbine engine 10 shown is merely an example. In other exemplary embodiments, the turbine engine 10 may have any other suitable configuration. For example, in other exemplary embodiments, the fan 38 may be configured in any other suitable manner (e.g., as a fixed-pitch fan) and may also be supported using any other suitable fan frame configuration. The turbine engine 10 may also be a direct-drive engine without a power gearbox. The fan speed is the same as the low-pressure shaft speed of the direct-drive engine. Furthermore, in other exemplary embodiments, any other suitable number or configuration of compressors, turbines, shafts, or combinations thereof may be provided. In some other exemplary embodiments, aspects of this disclosure may be incorporated into any other suitable turbine engine, such as a turbofan engine, propeller engine, turbojet engine, turboprop engine, or turboshaft engine.

[0039] Figure 2 It is a section taken along the longitudinal centerline axis 12, such as Figure 1 A cross-sectional side view of an exemplary combustor 26 of the turbocharged engine 16 shown. Figure 2An example of a dual-annular premixed cyclone (TAPS) type burner is depicted, and is generally an annular burner extending circumferentially around a longitudinal centerline axis 12. The burner 26 includes a shroud 80 consisting of an inner shroud 82 and an outer shroud 84, and a burner liner 86 having an inner liner 88 and an outer liner 90. Each of the inner liner 88 and the outer liner 90 is an annular liner extending circumferentially around a longitudinal centerline axis 12. In this respect, an annular opening 92 formed between the inner shroud 82 and the outer shroud 84 allows compressed air 65a to enter the burner 26 in a generally axial direction through a diffuser opening, as defined by the longitudinal centerline axis 94 of the dome orifice. The compressed air 65a can enter a first chamber 96 defined at least partially by an annular dome assembly 98. As will be discussed in more detail below, a portion of the compressed air 65a in the first chamber 96 can be used for combustion, while another portion can be used for cooling the burner 26.

[0040] A dome assembly 98 extends between an inner liner 88 and an outer liner 90. The dome assembly 98 includes an outer annular dome 104 and a heat shield 128, each coaxially arranged about a longitudinal centerline axis 12. The dome assembly 98 defines a plurality of circumferentially spaced annular dome apertures 97 extending through the outer annular dome 104 and the heat shield 128. For clarity, Figures 2 to 6 Only one dome assembly 98 is shown; however, the dome assembly 98 extends circumferentially around the longitudinal centerline axis 12. The dome aperture 97 of each dome assembly 98 defines the longitudinal centerline axis 94 of the dome aperture.

[0041] The inner liner 88, outer liner 90, and dome assembly 98 together define the combustion chamber 100. More specifically, the burner 26 includes an inner annular dome 102 attached to the front end of the inner liner 88 and an outer annular dome 104 attached to the front end of the outer liner 90. In the combustion chamber 100, an initial chemical reaction may occur in the ignited pilot fuel-oxidant mixture 108 injected into the combustion chamber 100 by the pilot swirler portion (described below) of the fuel nozzle mixer assembly 106 connected to the dome assembly 98 to produce combustion gases 66. In high-power operation of the burner 26, the main fuel-oxidant mixture 110 is also injected by the fuel nozzle mixer assembly 106 (as described below) into the combustion chamber 100. Figure 3A The main swirler section (described below) is injected into the combustion chamber 100 to produce combustion gas 66. The combustion gas 66 then flows further downstream into the HP turbine 28 and LP turbine 30 via the first-stage turbine nozzle 124 at the downstream end 116 of the combustion chamber 100. Figure 1 ).

[0042] The burner 26 also includes a plurality of fuel nozzle mixer assemblies 106 circumferentially spaced between an inner annular dome 102 and an outer annular dome 104. A plurality of profiled cups 118 circumferentially spaced around a longitudinal centerline axis 12 may be formed in the annular dome assembly 98, and each cup 118 defines a dome orifice 97 in which a cyclone separator, cyclone separator, or fuel nozzle mixer assembly 106 is mounted, attached, or otherwise integrated for introducing an air / fuel mixture into the combustion chamber 100. Notably, compressed air can be directed from the burner 26 to or through one or more fuel nozzle mixer assemblies 106 to support combustion at the upstream end of the combustion chamber 100.

[0043] Liquid and / or gaseous fuel is delivered to the burner 26 by a fuel distribution system (not shown) and introduced at the front end of the combustion chamber 100. In an exemplary embodiment, each fuel nozzle mixer assembly 106 may define an opening for receiving fuel injectors 120 (details omitted for clarity). Fuel injectors 120 may inject fuel in an axial direction (i.e., along the longitudinal centerline axis 94 of the dome orifice) and generally in a radial direction (orthogonal to the longitudinal centerline axis 94 of the dome orifice), wherein the fuel may swirl with incoming compressed air. Thus, each fuel nozzle mixer assembly 106 receives compressed air from the annular opening 92 and fuel from the corresponding fuel injector 120. Fuel and compressed air swirl and mix together through the fuel nozzle mixer assembly 106, and the resulting fuel-air mixture is discharged into the combustion chamber 100 for combustion.

[0044] The burner 26 may also include an igniter 122 extending through the liner 90, adapted to ignite the fuel-air mixture. Upon ignition, the resulting combustion gases 66 can flow in a generally axial direction (along the longitudinal centerline axis 94 of the dome orifice) through the combustion chamber 100, enter and pass through the turbine engine 10 (… Figure 1 The turbine section 27 of the turbine, wherein a portion of the thermal and / or kinetic energy from the combustion gas 66 is extracted via a sequential stage of turbine stator blades and turbine rotor blades. More specifically, the combustion gas 66 may flow into an annular first-stage turbine nozzle 124. As generally understood, the first-stage turbine nozzle 124 may be defined by an annular flow channel comprising a plurality of radially extending, circularly spaced nozzle blades (not shown) that rotate the gas, causing it to flow at an angle and impinge on the HP turbine 28. Figure 1 The first stage turbine blade (not shown).

[0045] As described above, each dome assembly 98 includes a heat shield 128 that insulates the annular dome assembly 98 from the extremely high temperatures generated in the combustion chamber 100 during engine operation. The inner annular dome 102, the outer annular dome 104, and the heat shield 128 may define a plurality of dome orifices 97 (e.g., dome orifices of cup 118) for receiving the fuel injector mixer assembly 106. As shown, in one embodiment, the plurality of openings are circular. However, in other embodiments, the openings may be oval, elliptical, polygonal, rectangular, or other non-circular cross-sections.

[0046] The burner 26 also includes a housing 130 extending circumferentially around a longitudinal centerline axis 12 and an inner housing 132 extending circumferentially around the longitudinal centerline axis 12. An outer flow passage 134 is defined between the housing 130 and the outer liner 90, and an inner flow passage 136 is defined between the inner housing 132 and the inner liner 88. The housing 130 and the inner housing 132 converge at an upstream end 138 of the burner 26 and together define a pressure boosting chamber 140. The housing 130 and the inner housing 132 are also connected to a diffuser 114. The diffuser 114 is in flow communication with the HP compressor 24 to receive a flow of compressed air 65 from the HP compressor 24 and to supply the flow of compressed air 65 into the pressure boosting chamber 140. An igniter 122 may be connected to the housing 130 and extends through the outer flow passage 134 and the outer liner 90. The igniter 122 provides an ignition source (e.g., a spark) to ignite the pilot fuel-oxidizer mixture 108. The main fuel-oxidant mixture 110 can be ignited by a pilot fuel-oxidant mixture 108, or the igniter 122 can also be used to ignite the main fuel-oxidant mixture 110.

[0047] Return to reference Figure 1 During operation, a certain amount of air 58 enters the nacelle 50 at the nacelle inlet 60, and is propelled through by the fan 38. A portion of the air 58 propelled by the fan 38 flows as core air 64 into the LP compressor 22. The core air 64 is compressed by the LP compressor 22 to produce compressed air 65. The compressed air 65 then flows to the HP compressor 24, where it is further compressed, thereby increasing its pressure. The compressed air 65 from the HP compressor 24 passes through the diffuser 114 (… Figure 2 The air 58, driven by fan 38, enters combustor 26. Another portion of the air 58 flows through bypass airflow passage 56, thus providing the flow of bypass air 62. Bypass air 62 provides most of the thrust to turbine engine 10.

[0048] Return to reference Figure 2As described above, compressed air 65 flows through diffuser 114, which reduces the velocity of the compressed air 65 entering pressure chamber 140. A portion of the compressed air 65 in pressure chamber 140 enters shroud 80 (schematically shown as compressed air 65a), while another portion of the compressed air 65 flows to outer flow passage 134 and inner flow passage 136 (schematically shown as the flow of compressed air 65b). Compressed air 65a passes through fuel nozzle mixer assembly 106 and mixes with fuel to produce pilot fuel-oxidant mixture 108 and main fuel-oxidant mixture 110, which are then ignited in primary combustion zone 142 or secondary combustion zone 144 to produce combustion gases 66. The flow of compressed air 65b in the outer flow passage 134 and the inner flow passage 136 can be used for various purposes, such as providing dilution air (not shown) to the combustion chamber 100 through dilution openings (not shown) in the inner liner 88 and the outer liner 90 for cooling the inner liner 88 and the outer liner 90, or for cooling other components of the turbine engine 10.

[0049] In the Figures 3A to 6 In the following description, the terms "axial" and "axially" refer to the direction and orientation extending substantially parallel to the longitudinal centerline axis 94 of the dome aperture. Furthermore, the terms "radial" and "radially" refer to the direction and orientation extending substantially perpendicular to the longitudinal centerline axis 94 of the dome aperture. Additionally, as used herein, the terms "circumferential" and "circumferentially" refer to the direction and orientation extending arcuately around the longitudinal centerline axis 94 of the dome aperture.

[0050] Now for joint reference Figure 3A and Figure 3B The heat shield mounting assembly 300 includes a metal dome 302 and a CMC heat shield 304, which are secured by a plurality of pin assemblies 306 arranged circumferentially around the longitudinal centerline axis 94 of the dome aperture. Figure 3A and Figure 3B The heat shield mounting assembly 300 can be used for reference. Figure 2 In the described dome assembly 98, the metallic dome 302 and the CMC heat shield 304 are not easily joined by metal forming operations such as brazing or welding. The metallic material of the dome 302 and the ceramic material of the heat shield 304 have different maximum operating temperatures (approximately 1600°F and approximately 2200°F, respectively), making it impractical to join the metallic dome 302 and the CMC heat shield 304 by joining operations such as brazing or welding.

[0051] Instead of brazing or welding, one or more fasteners are needed to join components made of different materials, such as the metal of the metal dome 302 and the ceramic of the CMC heat shield 304. However, the metal dome 302 and the CMC heat shield 304 have different thermal behaviors. Rigidly fixing the metal dome 302 and the CMC heat shield 304 in three dimensions may generate mechanical stress in the dome 302, the heat shield 304, or both.

[0052] The metallic dome 302 can be formed from a metal, such as, but not limited to, a nickel alloy or a cobalt alloy. In some examples, the material is cast or forged to form the metallic dome 302. The coefficient of thermal expansion of the metallic dome 302 can range from 7.5 in / in / °F to 10 × 10⁻¹⁰. -6 Within the range of in / in / °F. The coefficient of thermal expansion of CMC heat shield 304 is approximately one-third that of the coefficient of thermal expansion of the metal dome 302. Combustion chamber 100 ( Figure 2 It may experience extreme temperatures from cold climates (e.g., engine shutdown on cold days), ranging from temperatures as low as approximately -60°F to full-load operating temperatures as high as approximately 1400°F. The different thermal expansion of the metallic dome 302 and the CMC heat shield 304 causes substantial movement and shape changes of the dome 302 and the heat shield 304 relative to each other.

[0053] Dome 302 has an interior 308, an exterior 310, and a surface 312. The interior 308 and exterior 310 are generally annular and arranged around the longitudinal centerline 94 of the dome aperture. The surface 312 is generally planar and is disposed between the interior 308 and exterior 310. Dome 302 is a single integral component, such that the interior 308, exterior 310, and surface 312 are continuous and connected.

[0054] The heat shield 304 has an inner heat shield 314, an outer heat shield 316, and a face heat shield 318. The inner heat shield 314 and the outer heat shield 316 are generally annular in shape and arranged around the longitudinal centerline 94 of the dome-shaped aperture. The face heat shield 318 is generally planar and is disposed between the inner heat shield 314 and the outer heat shield 316. The diameter of the inner heat shield 314 is smaller than the diameter of the dome-shaped interior 308, and it is assembled within the dome-shaped interior 308. The heat shield 304 is a single integral component, such that the inner heat shield 314, the outer heat shield 316, and the face heat shield 318 are continuous and connected.

[0055] The dome 302 and the heat shield 304 are connected by a plurality of pin assemblies 306. Each of the plurality of pin assemblies 306 includes a fastener 320 having a head end 322, a pin end 324, and a thread 326 therebetween. The fastener 320 may preferably be made of a metallic material or metal alloy having similar thermal properties to the dome 302, such that the thermal expansion of the fastener 320 is similar to that of the dome 302. Due to the similar thermal expansion characteristics of the dome 302 and the fastener 320, the fastener 320 is fastened to the dome 302 at a threaded interface 327 between the thread 326 of the fastener 320 and a corresponding thread 328 in the dome 302. In this way, the pin end 324 of each fastener 320 is relatively fixed to the dome 302. Although the fastener 320 is described as threaded, other connection types are also contemplated, such as, but not limited to, pinning or welding the pins to the dome 302.

[0056] The diameter of pin end 324 is smaller than the diameter of the plurality of holes 330 in heat shield 304 to define a gap 346. Gap 346 provides a clearance between pin end 324 and holes 330 to accommodate different thermal growth in the longitudinal direction of dome 302 and heat shield 304 relative to the longitudinal centerline axis 94 of the dome aperture. In a configuration of a metallic dome 302 and CMC heat shield 304, the maximum gap 346 between pin end 324 and holes 330 occurs at the lowest temperature. In aircraft applications, low extreme temperatures can be expected under steady-state conditions, cold-climate shutdown conditions, extremely high altitudes, etc. At the highest temperatures, the minimum gap between pin end 324 and holes 330 can be expected, which may occur at the maximum power output of turbine engine 10. In some examples, gap 346 is between 0.001 inches and 0.015 inches. In some examples, gap 346 is between 0.004 inches and 0.008 inches.

[0057] Due to the annular shape of the dome interior 308 and the insulation interior 314, thermal expansion and contraction of the dome interior 308 and the insulation interior 314 relative to each other will primarily occur in the radial direction. When the fastener 320 is secured to the dome 302 via the threaded interface 327, the pin end 324 moves radially inward and radially outward (relative to the longitudinal centerline axis 94 of the dome orifice) as the dome interior 308 contracts inward and expands outward, respectively. When the pin end 324 retracts radially outward relative to the hole 330, the total length of the fastener 320, particularly the extent of the pin end 324, is sufficient to maintain engagement between the pin end 324 and the hole 330 at high temperatures. Similarly, the pin end 324 of the fastener 320 extends radially outward sufficiently such that, at extremely low temperatures, neither the threads 326 of the fastener 320 nor the dome interior 308 exerts potentially destructive radial inward loads on the insulation interior 314.

[0058] Furthermore, thermal expansion may occur axially, circumferentially, or both, relative to the longitudinal centerline axis 94 of the dome aperture. At the pin assembly 306, this thermal expansion and contraction can be accommodated by maintaining a clearance fit between the pin end 324 and the hole 330. The fit between the pin end 324 and the hole 330 can be designed such that a clearance 346 is maintained between the pin end 324 and the hole 330 under both extreme high and low temperatures. The clearance 346 allows the dome 302 and the heat shield 304, particularly the dome interior 308 and the heat shield interior 314, to continuously expand and contract relative to each other under all temperature and operating conditions. Therefore, as described herein, the heat shield 304 is secured to the dome 302 such that the heat shield 304 is unconstrained relative to the dome 302 to allow relative thermal expansion and contraction in the radial direction relative to the longitudinal centerline axis 94 of the dome aperture.

[0059] exist Figure 3A and Figure 3B In this example, compressed air 65a flows into the cooling air flow gap 334 through an opening (not shown) formed in the dome 302. In this example, compressed air 65a will leak from the first cavity 96 into the cooling air flow gap 334. To prevent or control the leakage of compressed air 65a from the first cavity 96, a first seal 332 is disposed between the interior 308 of the dome and the interior 314 of the heat shield, and concentrically aligns the heat shield 304 with the dome 302. The first seal 332 may be a piston seal. The more leakage through the first seal 332, the less compressed air 65a is allowed to be introduced through the opening (not shown) formed in the dome 302, which reduces the impact cooling available for cooling the back of the heat shield 304. The first seal 332 is annular and circumferentially arranged around the longitudinal centerline axis 94 of the dome opening, located in front of the pin assembly 306.

[0060] A second seal 336 is disposed between the dome 302 and the heat shield 304 to prevent or meter compressed air 65a from flowing from the cooling air flow gap 334 into the combustion chamber 100. The second seal 336 may be a spline seal. The first seal 332 and the second seal 336 provide a relatively high pressure in the first chamber 96, a relatively low pressure in the combustion chamber 100, and a relatively intermediate pressure in the cooling air flow gap 334 that is lower than the pressure in the first chamber 96 but higher than the pressure in the combustion chamber 100. The pressure difference between the first chamber 96, the cooling air flow gap 334, and the combustion chamber 100 allows air to flow continuously through the cooling air flow gap 334. Compressed air 65a can exit the cooling air flow gap 334 through cooling air holes (not shown) in the heat shield 304. The flow of compressed air 65a through the heat shield 304 can be used to cool the region of the combustion chamber closest to the heat shield 304 via convective heat transfer from the heat shield 304 to the compressed air 65a flowing through it. Furthermore, the flow of compressed air 65a through the heat shield 304 can cool the heat shield by moving the combustion in the combustion chamber 100 downstream and away from the heat shield 304.

[0061] The first seal 332 has an inner ring 338 and an outer ring 340. For example... Figure 3A As shown, the inner ring 338 contacts the interior 314 of the heat shield, and the outer ring 340 contacts the interior 308 of the dome. The inner ring 338 and outer ring 340 can be made of a wear-resistant material, or can have a surface finish similar to that of a wear-resistant material. Examples of wear-resistant materials include cobalt alloys or chrome plating. Due to the different relative movements between the inner rings 338 and 340 of the first seal 332, and between the dome 302 and the heat shield 304, other materials or surface treatments known in the art can be used for the inner rings 338 and 340 to maintain sufficient hardness and wear resistance. The first seal 332 is axially held relative to the longitudinal centerline axis 94 of the dome orifice by a groove 342 formed in the interior 308 of the dome. The groove 342 prevents the first seal 332 from disengaging, but allows the first seal 332 to move relative to the metallic dome 302. The first seal 332 is tightened around the heat shield 304, but moves with the heat shield 304 as the heat shield 304 moves. The first seal 332 provides a seal at the inner diameter of the seal (e.g., together with the heat shield 304) and on the axial surface of the dome 302 that contacts the metal.

[0062] The second seal 336 is installed in a corresponding groove 344 in the dome-shaped surface 312 and the outer surface 316 of the heat shield. The groove 344 captures the second seal 336 and prevents it from disengaging. Figure 3A The position shown. The second seal 336 abuts against the axially facing surface of the heat shield 304 (relative to the longitudinal centerline axis 94 of the dome orifice).

[0063] During the service life of the turbine engine 10, the heat shield 304 may require periodic replacement due to, but not limited to, wear, material loss, coating loss, etc. Multiple pin assemblies 306, the first seal 332, and the second seal 336 allow for the non-destructive mechanical removal and replacement of the heat shield 304 without the need for any cutting, melting, or subsequent re-aging that might be required to remove and replace other equivalent welded or brazed heat shield mounting assemblies. Furthermore, welding or brazing assemblies may require breaking the dome to replace the heat shield. The heat shield mounting assembly 300 allows for the removal of the pin assemblies 306 by unscrewing the fasteners 320 from the dome 302, thereby allowing for the replacement of the heat shield 304. After the multiple pin assemblies 306 are removed from the heat shield mounting assembly 300, the heat shield 304 can be removed axially rearward. After the heat shield 304 is removed from the heat shield mounting assembly 300, the first seal 332 and the second seal 336 can be replaced. This disassembly does not require damaging the dome 302 or removing the dome 302 from the burner 26.

[0064] Figure 4 and Figure 5 Schematic cross-sectional views of heat shield mounting assemblies 400 and 500 are shown respectively. Except for the sealing configuration described below, heat shield mounting assemblies 400 and 500 are similar to those referenced. Figure 3A and Figure 3B The heat shield mounting assembly 300 is substantially similar. Therefore, the same reference numerals will be used for components of heat shield mounting assemblies 400 and 500 that are identical or similar to those of heat shield mounting assembly 300. The above description of these components also applies to this embodiment, and detailed descriptions of these components are omitted here.

[0065] Now for reference Figure 4 The heat shield mounting assembly 400 includes a first seal 432. The first seal 432 may be a brush seal. The first seal 432 is mounted in a recess 342 within the dome interior 308. The first seal 432 is annular, circumferentially arranged around the longitudinal centerline axis 94 of the dome aperture, located in front of each of the plurality of pin assemblies 306, and concentrically aligns the heat shield 304 with the dome 302. The first seal 432 provides a pressure barrier between the first cavity 96 and the cooling airflow gap 334 between the dome 302 and the heat shield 304. The first seal 432 allows a metered portion of compressed air 65a to flow from the first cavity 96 to the cooling airflow gap 334, thereby maintaining a higher pressure in the first cavity 96 relative to the cooling airflow gap 334. The first seal 432 engages with the interior 308 of the dome; however, the bristles of the first seal 434 are flexible to allow any movement or misalignment between the heat shield 304 and the dome 302, while limiting the amount of air entering or leaving the cooling airflow gap 334.

[0066] The first seal 432 includes a brush seal housing 438 and a brush 440. The brush 440 is constrained by the brush seal housing 438, which engages or is secured to the interior 308 of the dome. Figure 4 As schematically shown, brush 440 has multiple strand-like members, also referred to as bristles, each of which is independently flexible and compliant. Brush 440 may be made of metal, polymer, plastic, composite material, or any other suitable material to provide flexibility and compliance, maintaining the required amount of compressed air 65a flowing through while retaining pressure and withstanding the operating conditions of the heat shield mounting assembly 400. This compliance and flexibility allows brush 440 to elastically deform to accommodate interference, thermal expansion, misalignment, vibration, or movement of dome 302, heat shield 304, or both dome 302 and heat shield 304. Furthermore, brush 440, specifically, with its multiple strand-like members, allows a metering portion of the flow rate of compressed air 65a to flow through brush 440, rather than around the first seal 432, or also allows flow around the first seal 432. The metered flow rate of compressed air 65a maintains the pressure difference between the first chamber 96 and the cooling air flow gap 334, allowing compressed air 65b to flow continuously through the cooling air flow gap 334, thereby maintaining continuous and uniform cooling of the heat shield 304.

[0067] Now for reference Figure 5 The heat shield mounting assembly 500 includes a first seal 532. The first seal 532 may be a C-shaped seal. The first seal 532 is mounted in a recess 342 within the dome interior 308. The first seal 532 is annular, circumferentially arranged around the longitudinal centerline axis 94 of the dome aperture, in front of the pin assembly 306, and concentrically aligns the heat shield 304 with the dome 302. The first seal 532 provides a pressure barrier between the first cavity 96 and the cooling airflow gap 334 between the dome 302 and the heat shield 304. The first seal 532 allows a metered portion of compressed air 65a to flow from the first cavity 96 to the cooling airflow gap 334, thereby maintaining a higher pressure in the first cavity 96 relative to the cooling airflow gap 334.

[0068] The first seal 532 has a C-shaped cross-section with its opening facing forward, towards the relatively high pressure of the first cavity 96, and also towards the main flow of compressed air 65a. The brush 440 is axially constrained by the groove 342 in both the front-rear directions. The first seal 532 contacts the dome 302 radially outward at the groove 342 and contacts the heat shield 304 radially inward at the interior 314 of the heat shield. The pressure difference between the first cavity 96 and the cooling air flow gap 334 pressurizes the first seal 532 to maintain the engagement of the first seal 534 with the metal dome 302 and the heat shield 304.

[0069] The first seal 532 is a single, integral component and is relatively compliant and flexible. The first seal can be made of a polymer material, metal, or any other suitable material that provides compliance and flexibility. This compliance and flexibility allow the first seal 532 to plastically deform to accommodate interference, thermal expansion, misalignment, vibration, or movement of the dome 302, the heat shield 304, or both. Furthermore, the plastic deformation of the first seal 532 allows a metered flow of a portion of the compressed air 65a to flow around the first seal 532. This metered flow of compressed air 65a maintains the pressure difference between the first cavity 96 and the cooling air flow gap 334, allowing compressed air 65b to flow continuously through the cooling air flow gap 334, thereby maintaining continuous and uniform cooling of the heat shield 304.

[0070] Figure 6 A schematic cross-sectional view of the heat shield mounting assembly 600 is shown. The heat shield mounting assembly 600 is compared with a reference... Figure 3A and Figure 3B The heat shield mounting assembly 300 is substantially similar to the one described above, except that it includes a bushing 646, as described below. Therefore, the same reference numerals will be used for components of the heat shield mounting assembly 600 that are identical or similar to those of the heat shield mounting assembly 300. The above description of these components also applies to this embodiment, and detailed descriptions of these components are omitted here.

[0071] In the heat shield mounting assembly 600, multiple components functionally similar to multiple pin assemblies 306 ( Figures 3A-5 The pin assembly 606 secures the dome 302 and the heat shield 604 together. The heat shield 604 includes a heat shield interior 614 and has a plurality of holes 630 at each pin assembly 606. The pin assembly 606 also includes a bushing 646. The bushing 646 is secured in the holes 630 in the heat shield interior 614. The bushing 646 is made of a high-temperature resistant and high-wear-resistant alloy, such as, but not limited to, a cobalt alloy.

[0072] Because the bushing 646 is fixed relative to the interior 614 of the heat shield, and because the fastener 320 is fixed relative to the interior 308 of the dome, relative deformation, movement, thermal expansion, vibration, etc., cause relative movement between the pin end 324 and the inner diameter 648 of the bushing 646. The material of the bushing 646 is more durable than that of the fastener 320, which makes the bushing 646 wear at a slower rate than the fastener 320, thereby extending the life of the fastener 320 (compared to the embodiment without the bushing 646).

[0073] The bushing 646 can be made of a harder material than the fastener 320 and acts as a sacrificial component, experiencing wear due to the relative movement of the pin assembly 606, but preventing such wear on the fastener 320. In contrast to the fastener 320, the service life of the fastener 320 is extended through the wear of the bushing 646. This is as in examples without the bushing 646 (e.g., Figure 3A and Figure 3B (), providing a gap to allow relative movement of the heat shield 604 during expansion.

[0074] During maintenance and replacement, the heat shield mounting assembly 600 can be disassembled by first removing fastener 320, as described with respect to the heat shield mounting assembly 300. The heat shield 604, including the bushing 646 mounted thereon, can then be removed from the rear to evaluate, maintain, or replace one or more components. If one or more bushings 646 are worn, but the heat shield 604 is still usable, one or more worn bushings 646 can be removed and replaced. As mentioned above, this may be more cost-effective than replacing the heat shield 604. As mentioned above, the bushing 646 is installed within the heat shield 604 with a clearance. The fastener 320 can be designed to retain the bushing within the hole 630 (e.g., a shoulder can be provided in the pin end 324 of the fastener 320). The bushing 646 can be press-fitted into the hole 630, screwed into the hole, or bonded to the hole with adhesive, or a combination thereof. Various heat shield mounting assemblies 300, 400, 500, and 600 are shown including a cooling air flow gap 334 defined at the downstream end by a second seal 336 to maintain an intermediate pressure within the cooling air flow gap 334. Consider embodiments without the second seal 336, which only include a relatively higher pressure in the first chamber 96, a lower pressure in the cooling air flow gap 334, and a lower pressure in the combustion chamber 100. In these embodiments, the pressures in the cooling air flow gap 334 and the combustion chamber 100 are substantially equal.

[0075] Furthermore, embodiments are considered where no compressed air 65a flows through or surrounds the first seal 332, first seal 432, or first seal 532. In these embodiments, high pressure is maintained in the first cavity 96, and low pressure is maintained downstream of the first seal 332, first seal 432, or first seal 532.

[0076] In a heat shield mounting assembly, a heat shield is attached to a dome to protect the dome and other burner components from heat generated during combustion. The heat shield can be made of composite materials, including CMC materials, which are not easily joined by bonding processes requiring melting and subsequent curing of the material, such as welding or brazing. The dome can be made of metallic materials. A dome made of metallic materials and a heat shield made of CMC materials will experience different rates of thermal expansion and contraction due to burner operation, thus generating heat. An assembly using fasteners secures the heat shield to the dome and allows the dome and heat shield to thermally expand and contract relative to each other in the radial direction.

[0077] As described above, the heat shield can be detachably assembled onto the dome using fasteners, and the heat shield mounting assembly can be disassembled, inspected, and maintained without cutting or melting burner components.

[0078] Further aspects are provided by the following items.

[0079] A combustor for a turbine engine includes a mixer assembly disposed at a front end of the combustor for receiving and mixing fuel and air, and injecting the fuel and air into a combustion chamber for combustion. The mixer assembly generally defines a longitudinal centerline axis. The at least one dome includes an interior dome and a generally planar dome facet, the interior of which is generally annular in shape and arranged around the longitudinal centerline axis. The at least one heat shield is fastened to the at least one dome and is unconstrained relative to the at least one dome to allow relative thermal expansion and contraction in the radial direction relative to the longitudinal centerline axis. The heat shield includes an interior that is (i) generally annular in shape, (ii) arranged around the longitudinal centerline axis, and (iii) has a diameter smaller than that of the interior of the dome. (iv) an inner part assembled inside the dome; and a heat shield facet that thermally protects the dome facet from the heat generated by combustion; a plurality of pin assemblies circumferentially arranged around the longitudinal centerline axis and securing the at least one heat shield to the at least one dome, the plurality of pin assemblies including fasteners having pin ends fitted into holes in the interior of the heat shield in a clearance fit, the fasteners being secured to the interior of the dome, the pin ends sliding in the holes during relative thermal expansion and contraction between the at least one dome and the at least one heat shield; and a seal circumferentially arranged around the longitudinal centerline axis in front of the plurality of pin assemblies, between the interior of the dome and the interior of the heat shield, for maintaining the concentricity of the interior of the heat shield relative to the interior of the dome.

[0080] According to the burner described in the preceding clause, the interior of the dome includes a groove, and the seal is assembled in the groove.

[0081] The burner according to any of the preceding clauses, wherein the fastener is secured to the dome by a fastener thread and a corresponding dome thread.

[0082] The burner according to any of the preceding clauses, wherein the heat shield is assembled to the dome without melting and subsequent material curing.

[0083] The burner according to any of the preceding clauses, wherein the seal is a brush seal comprising a plurality of solid rings and a brush, the brush contacting the interior of the heat shield, and the brush having a plurality of bundle-like members.

[0084] According to the burner described in the foregoing clause, the brush is made of metal, polymer, plastic or composite material.

[0085] The burner according to any of the preceding clauses, wherein the seal is a C-shaped seal.

[0086] According to the burner described in the foregoing clause, the C-shaped seal includes a forward-facing opening.

[0087] The burner according to any of the preceding clauses, wherein the seal is a piston seal comprising an inner ring and an outer ring, the inner ring contacting the interior of the heat shield and the outer ring contacting the interior of the dome.

[0088] According to the burner described in the foregoing clause, the inner ring, the outer ring, or both the inner ring and the outer ring are made of a cobalt alloy.

[0089] A burner according to any of the foregoing clauses, wherein the inner ring, the outer ring, or both the inner ring and the outer ring are chrome plated.

[0090] The burner according to any of the preceding clauses further includes a bushing fixed in the hole, the bushing allowing relative movement between the pin end and the bushing.

[0091] According to the burner described in the foregoing clause, the bushing is press-fitted into the hole, screwed into the hole, or bonded to the hole with an adhesive.

[0092] The burner according to any of the preceding clauses, wherein the seal is a first seal, the dome defines a cavity, and the burner further includes: a second seal disposed between the dome and the heat shield; and a cooling air flow gap defined by the first seal, the second seal, the dome, and the heat shield, wherein the cavity is at a relatively high pressure, the combustion chamber is at a relatively low pressure, and the cooling air flow gap is at a relatively intermediate pressure that is less than the pressure of the cavity but greater than the pressure of the combustion chamber.

[0093] According to the burner described in the foregoing clause, wherein the first seal restricts the flow of compressed air from the cavity to the cooling air flow gap.

[0094] According to the burner described in the foregoing clause, the second seal restricts the flow of compressed air from the cooling air flow gap to the combustion chamber, maintaining the relative intermediate pressure in the cooling air flow gap and the relative low pressure in the combustion chamber.

[0095] A turbine engine includes a compressor section providing a compressed air flow; a fuel system providing a fuel supply; a combustor located downstream of the compressor section, the combustor receiving the compressed air flow and the fuel supply for combustion of the compressed air flow and the fuel supply to produce combustion gases, the combustor comprising: a fuel nozzle mixer assembly disposed at a front end of the combustor for receiving and mixing fuel and air, and injecting the fuel and air into a combustion chamber for combustion; at least one dome defining a longitudinal centerline axis, the at least one dome including a dome interior and a generally planar dome facet, the dome interior being generally annular in shape and arranged around the longitudinal centerline axis; and at least one heat shield fixed to the at least one dome and unconstrained relative to the at least one dome to allow relative thermal expansion and contraction in the radial direction relative to the longitudinal centerline axis, the heat shield comprising: a heat shield interior, the heat shield interior (i) being generally... The at least one heat shield is assembled to the inside of the at least one dome, comprising: (ii) an annular shape, (iii) arranged around the longitudinal centerline axis, (iv) having a diameter smaller than the interior of the dome; and (ii) a heat shield facet that thermally protects the dome facet from the heat generated by combustion; a plurality of pin assemblies arranged circumferentially around the longitudinal centerline axis and securing the at least one heat shield to the at least one dome, the plurality of pin assemblies including fasteners having pin ends fitted into holes in the interior of the heat shield in a clearance fit, the fasteners being fixed to the interior of the dome, the pin ends sliding in the holes during relative thermal expansion and contraction between the at least one dome and the at least one heat shield; a seal arranged circumferentially around the longitudinal centerline axis in front of the plurality of pin assemblies, between the interior of the dome and the interior of the heat shield, for maintaining the concentricity of the interior of the heat shield relative to the interior of the dome; and a turbine section located downstream of the burner, the turbine section including a turbine that rotates due to the combustion gases.

[0096] According to the aforementioned clause of the turbine engine, wherein the seal is a first seal, the dome defines a cavity, and the combustor further includes: a second seal disposed between the dome and the heat shield; and a cooling air flow gap defined by the seal, the second seal, the dome, and the heat shield, wherein the cavity is at a relatively high pressure, the combustion chamber is at a relatively low pressure, and the cooling air flow gap is at a relatively intermediate pressure that is less than the pressure of the cavity but greater than the pressure of the combustion chamber.

[0097] According to the turbine engine described in the foregoing clause, the first seal restricts the flow of compressed air from the cavity to the cooling air flow gap, maintaining the relative high pressure in the cavity and the relative intermediate pressure in the cooling air flow gap.

[0098] According to the turbine engine described in the foregoing clause, the second seal restricts the flow of compressed air from the cooling air flow gap to the combustion chamber, maintaining the relative intermediate pressure in the cooling air flow gap and the relative low pressure in the combustion chamber.

[0099] A method for assembling a heat shield mounting assembly, the method comprising inserting the heat shield interior of a heat shield into the dome interior of a dome, the heat shield interior and the dome interior being generally annular, the diameter of the heat shield interior being smaller than the diameter of the dome interior; assembling a plurality of pin assemblies by inserting a plurality of fasteners into the dome interior; inserting the pin end of each of the plurality of fasteners into one of a plurality of holes in the heat shield interior in a clearance fit such that the heat shield and the dome are radially unconstrained relative to each other; and assembling a seal between the dome interior and the heat shield interior in front of the plurality of pin assemblies, wherein the method does not involve melting any components.

[0100] The method described in the foregoing clause further includes securing a plurality of bushings into the plurality of holes in the heat insulation cover, such that the pin end is assembled onto the bushing in a clearance fit manner.

[0101] The method according to any of the preceding clauses, wherein the seal is a piston seal comprising an inner ring and an outer ring, the inner ring contacting the interior of the heat shield and the outer ring contacting the interior of the dome.

[0102] The method according to any of the preceding clauses, wherein the seal is a brush seal comprising a plurality of solid rings and a brush, the brush contacting the interior of the heat insulation cover, the brush having a plurality of bundle-like members.

[0103] The method according to any of the preceding clauses, wherein the seal is a C-shaped seal.

[0104] The method according to any of the preceding clauses further includes assembling a second seal between the dome and the heat shield to define a cooling airflow gap between the seal, the second seal, the dome, and the heat shield.

[0105] A method for removing and reassembling a heat shield from a heat shield mounting assembly, the method comprising removing a plurality of fasteners secured to a dome and having pin ends that clearance-fit with a plurality of holes in the heat shield, moving the heat shield rearward, inspecting the heat shield and the plurality of fasteners, optionally replacing one or more of the heat shield and the fasteners, inserting a generally annular heat shield interior into the generally annular dome interior from the rear, and mounting the plurality of fasteners through the dome and the heat shield, wherein the method does not involve cutting or melting any components.

[0106] The method described in the foregoing clauses further includes inspecting and optionally replacing the seal between the dome and the heat shield.

[0107] The method according to any of the foregoing clauses further includes inspecting and optionally replacing multiple bushings on the heat shield.

[0108] While the foregoing description pertains to preferred embodiments of the present disclosure, those skilled in the art will understand that other variations and modifications can be made without departing from the present disclosure. Furthermore, even if not explicitly stated above, features described in connection with one embodiment of the present disclosure can be used in conjunction with other embodiments.

Claims

1. A combustor for a turbine engine, characterized in that, The burner includes: A fuel nozzle mixer assembly, disposed at the front end of the burner, is used to receive and mix fuel and air, and to inject the fuel and air into the combustion chamber for combustion; At least one dome, the at least one dome defining a longitudinal centerline axis, the at least one dome including a dome interior and a generally planar dome surface, the dome interior being generally annular in shape and arranged around the longitudinal centerline axis; At least one heat shield, the heat shield being fastened to the at least one dome and unconstrained relative to the at least one dome to allow relative thermal expansion and contraction in the radial direction relative to the longitudinal centerline axis, the heat shield comprising: Inside the heat shield, the interior is (i) generally annular, (ii) arranged around the longitudinal centerline axis, (iii) having a diameter smaller than the interior of the dome, and (iv) assembled inside the interior of the dome; and A heat shield face, which thermally protects the dome face from the heat generated by the combustion; A plurality of pin assemblies, circumferentially arranged around the longitudinal centerline axis, secure the at least one heat shield to the at least one dome. Each pin assembly includes a fastener with a pin end fitted into a hole within the heat shield in a clearance fit. The fastener is fixed to the interior of the dome, and the pin end slides within the hole during relative thermal expansion and contraction between the at least one dome and the at least one heat shield. A seal is arranged circumferentially around the longitudinal centerline axis, in front of the plurality of pin assemblies, between the interior of the dome and the interior of the heat shield, for maintaining the concentricity of the interior of the heat shield relative to the interior of the dome.

2. The burner according to claim 1, characterized in that, in, The dome includes a groove inside, and the seal is installed in the groove.

3. The burner according to claim 1, characterized in that, in, The fastener is secured to the dome by a fastener thread and a corresponding dome thread.

4. The burner according to claim 1, characterized in that, in, The heat shield is assembled to the dome without the need for melting and subsequent material curing.

5. The burner according to claim 1, characterized in that, in, The seal is a brush seal, which includes a brush seal housing and a brush. The brush contacts the interior of the heat insulation cover and has multiple bundle-like components.

6. The burner according to claim 5, characterized in that, in, The brush is made of metal, polymer, plastic or composite material.

7. The burner according to claim 1, characterized in that, in, The seal is a C-shaped seal.

8. The burner according to claim 7, characterized in that, in, The C-shaped seal includes a forward-facing opening.

9. The burner according to claim 1, characterized in that, It further includes a bushing fixed in the hole, the bushing allowing relative movement between the pin end and the bushing.

10. The burner according to claim 9, characterized in that, in, The bushing is press-fitted into the hole, screwed into the hole, or bonded to the hole with adhesive.

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