Split-type protective cover for vibration damping

Abstract

A method, apparatus, system and article are disclosed. A split shroud for an inner shroud of a gas turbine engine comprises: at least one front shroud segment and at least one rear shroud segment, the at least one rear shroud segment being coupled to the at least one front shroud segment, the at least one front shroud segment and the at least one rear shroud segment forming a split line.

Description

Technical Field

[0001] The present disclosure relates generally to gas turbines, and more particularly, to a split shroud for vibration reduction. Background Art

[0002] A gas turbine engine generally includes an inlet section, a compressor section, a combustion section, a turbine section, and an exhaust section in a sequential flow order. In operation, air enters the inlet section and flows to the compressor section, where one or more axial compressors progressively compress the air until it reaches the combustion section, thereby producing combustion gases. The combustion gases flow from the combustion section through a hot gas path defined within the turbine section, and then exit the turbine section via the exhaust section. Summary of the invention

[0003] Methods, apparatus, systems, and articles of manufacture for reducing turbine engine vibrations are disclosed.

[0004] Certain examples provide an apparatus including at least one front shroud segment and at least one rear shroud segment, the at least one rear shroud segment coupled to the at least one front shroud segment, the at least one front shroud segment and the at least one rear shroud segment forming a split line.

[0005] Certain examples provide a gas turbine engine comprising: a split shroud damper comprising at least one front shroud segment and at least one rear shroud segment, at least one rear shroud segment being coupled to at least one front shroud segment, at least one front shroud segment and at least one rear shroud segment forming a split line; and a sealed box coupled to at least one front shroud segment and at least one rear shroud segment.

[0006] Certain examples provide an apparatus comprising a first device for detuning and / or damping component vibrations and a second device for detuning and / or damping component vibrations, the second device for detuning and / or damping component vibrations being coupled to the first device for detuning and / or damping component vibrations. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 An example gas turbine engine is shown.

[0008] Figure 2 Shows Figure 1 An example cross-sectional side view of a high pressure compressor of a turbofan engine is shown in .

[0009] Figure 3 An example perspective view of a first example split shroud damper is shown.

[0010] Figure 4A An example top view of a second example split shroud damper is illustrated.

[0011] Figure 4B An example top view of a third example split shroud damper is shown.

[0012] The drawings are not drawn to scale. On the contrary, the thickness of the layer or region can be magnified in the drawings. Although the layers and regions with clear lines and boundaries are shown in the figures, some or all of these lines and / or boundaries may be idealized. In fact, the boundaries and / or lines may be unobservable, mixed and / or irregular. Generally, the same reference numerals will be used throughout the drawings and the accompanying written description to refer to the same or similar parts. As used in this patent, it is stated that any part (e.g., layer, film, region, zone or plate) is in any way on (e.g., positioned on, located on, set on or formed on, etc.) another part, indicating that either the referenced part is in contact with another part, or the referenced part is above another part, and one or more intermediate parts are located between them. As used herein, unless otherwise specified, connection references (e.g., attachment, connection, connection and engagement) may include intermediate members between elements referenced by the connection reference and / or relative movement between those elements. Therefore, connection references do not necessarily infer that two elements are directly connected and / or are in a fixed relationship with each other. As used herein, stating that any part is "in contact with" another part is defined to mean that there is no intermediate part between the two parts. DETAILED DESCRIPTION

[0013] Engine and component vibrations occur during normal engine operation. For example, forces acting on one or more airfoils (e.g., blades, vanes, etc.) during engine operation may cause one or more airfoils to vibrate an undesirable amount, thereby introducing stress and ultimately wear on one or more airfoils. Component vibration mode responses to engine vibrations or other sources include airfoil mode responses (e.g., one airfoil is vibrating), soldier mode responses (e.g., one or more airfoils attached to a shroud vibrate together), etc. Vibration mode responses may eventually lead to airfoil wear (e.g., trunnion cracking, trunnion locking, etc.). There is a constant need to reduce the vibration response of components. Certain examples provide a split shroud damper that increases damping (e.g., friction damping) between split connections, thereby improving the durability of one or more airfoils and an associated engine.

[0014] In the detailed description below, reference is made to the accompanying drawings which form a part thereof, and in which specific examples that can be put into practice are shown by way of example. These examples are described in sufficient detail to enable those skilled in the art to practice the subject matter, and it should be understood that other examples can be utilized. Therefore, the following detailed description is provided to describe example embodiments, and is not to be considered as limiting the scope of the subject matter described in this disclosure. Certain features from the different aspects described below can be combined to form yet new aspects of the subject matter discussed below.

[0015] Descriptors "first", "second", "third", etc. are used herein to identify multiple elements or components that can be referred to separately. Unless otherwise specified or understood from the context of their use, such descriptors are not intended to confer any meaning of priority, physical order or arrangement in a list, or time ordering, but are merely used as labels to refer to multiple elements or components, respectively, to facilitate understanding of the disclosed examples. In some examples, the descriptor "first" can be used to refer to an element in the detailed description, while the same element can be referred to in the claims by different descriptors such as "second" or "third". In such cases, it should be understood that such descriptors are only used to facilitate reference to multiple elements or components.

[0016] The terms "upstream" and "downstream" refer to relative directions with respect to the flow of fluid in a fluid path. For example, "upstream" refers to the direction from which the fluid is flowing, and "downstream" refers to the direction toward which the fluid is flowing. As used herein, "vertical" refers to a direction perpendicular to the ground. As used herein, "horizontal" refers to a direction parallel to the centerline of the gas turbine engine 100. As used herein, "lateral" refers to a direction perpendicular to the axial vertical direction (e.g., entering and leaving the engine). Figure 1 , 2 etc. plane).

[0017] Various terms are used herein to describe the orientation of features. As used herein, the orientation of features, forces, and moments are described with reference to the axial direction, radial direction, and circumferential direction of the vehicle associated with the features, forces, and moments. In general, the figures are labeled with a set of axes, including an axial axis A, a radial axis R, and a circumferential axis C.

[0018] "Include" and "comprising" (and all their forms and tenses) are used herein as open-ended terms. Thus, whenever a claim adopts any form of "include" or "comprising" (e.g., includes, contains, has, etc.) as a preamble or in any type of claim recitation, it should be understood that additional elements, terms, etc. may be present without exceeding the scope of the corresponding claim or recitation. As used herein, when the phrase "at least" is used as a transitional term, such as in the preamble of a claim, it is open-ended in the same manner as the terms "include" and "comprising" are open-ended. The term "and / or" when used in the form of, for example, A, B, and / or C, refers to any combination or subset of A, B, C, such as (1) A alone, (2) B alone, (3) C alone, (4) A and B, (5) A and C, (6) B and C, and (7) A and B and C. As used herein in the context of describing structures, components, items, objects, and / or things, the phrase "at least one of A and B" is intended to refer to any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. Similarly, as used herein in the context of describing structures, components, items, objects, and / or things, the phrase "at least one of A or B" is intended to refer to any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. As used herein in the context of describing the performance or execution of processes, instructions, actions, activities, and / or steps, the phrase "at least one of A and B" is intended to refer to any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. Similarly, as used herein in the context of describing the performance or execution of processes, instructions, actions, activities, and / or steps, the phrase "at least one of A or B" is intended to refer to any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B.

[0019] As used herein, singular references (e.g., "a", "a", "first", "second", etc.) do not exclude the plural. As used herein, the term "a" or "an" entity refers to one or more of that entity. The terms "a" (or "a"), "one or more" and "at least one" may be used interchangeably herein. In addition, although listed separately, multiple devices, elements or method actions may be implemented by, for example, a single unit or processor. In addition, although individual features may be included in different examples or claims, these may be combined, and inclusion in different examples or claims does not mean that the combination of features is not feasible and / or not advantageous.

[0020] The gas turbine engine includes multiple rows of buckets, multiple rows of rotor blades, etc. In some examples, the buckets of the gas turbine engine are variable stator buckets ("VSV"), which allow individual stator buckets to rotate about their respective axes (e.g., radial axes). In some existing designs, the VSV and shroud assembly include a 360-degree segment, two 180-degree segments, or other number of segments that form a single row of stators associated with a particular stage of the compressor. Although the examples disclosed herein are described with reference to a stator in a compressor, the examples disclosed herein may be applied to stators in any section of a gas turbine engine.

[0021] In some examples, the rotation of the VSV is controlled by a trunnion disposed within the shroud and / or a sealed box below the shroud and VSV. As used herein, a "trunnion" is a part and / or feature that allows parts and / or features to be supported thereon and / or rotated thereby. In some prior art, tests have shown that the trunnion may have unfavorable cracking and fatigue, depending on the vibration response mode (e.g., soldier mode response, etc.). In view of the shroud end mass, the vibration response during engine operation is based at least in part on the conflicting design parameters of the VSV (e.g., stiffness, durability, etc.). This response can cause the trunnion to lock (e.g., stop rotating) within the sealed box, which can reduce engine performance and fatigue the VSV. For example, during a particular vibration response, the cylindrical shape of the trunnion may deform in a manner that causes three points of the trunnion to contact the shroud, which prevents the trunnion from rotating, thereby locking the VSV. In addition, trunnion locking can cause fatigue and cracking of the cylindrical trunnion.

[0022] Based on the reduction of engine vibration, the examples disclosed herein can reduce the undesirable effects caused by these deformations in the engine. For example, by segmenting the inner shroud of the gas turbine engine to form a split shroud damper, the vibration response is mitigated. The split shroud damper can include one or more shroud segments connected via bolted joints.

[0023] Reference will now be made in detail to examples of the present invention, one or more of which are illustrated in the accompanying drawings. Each example is provided to explain the present invention, not to limit the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the present invention without departing from the scope or spirit of the present invention. For example, a feature shown or described as part of one example may be used together with another example to produce yet another example. Therefore, the present invention is intended to encompass such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0024] Figure 1 1 is a schematic cross-sectional view of a prior art turbofan-type gas turbine engine 100 (“turbofan engine 100”). Figure 1As shown, turbofan engine 100 defines a longitudinal or axial centerline axis 102 extending therethrough for reference. Generally, turbofan engine 100 may include a core turbine or gas turbine engine 104 disposed downstream of a fan section 106 .

[0025] The core turbine 104 generally includes a substantially tubular casing 108 that defines an annular inlet 110. The casing 108 may be formed by a single shell or multiple shells. The casing 108 surrounds a compressor section having a supercharger or low-pressure compressor 112 ("LP compressor 112") and a high-pressure compressor 114 ("HP compressor 114"), a combustion section 116, a turbine section having a high-pressure turbine 118 ("HP turbine 118") and a low-pressure turbine 120 ("LP turbine 120"), and an exhaust section 122 in a series flow relationship. A high-pressure shaft or spool 124 ("HP shaft 124") is drivingly coupled to the HP turbine 118 and the HP compressor 114. A low-pressure shaft or spool 126 ("LP shaft 126") is drivingly coupled to the LP turbine 120 and the LP compressor 112. The LP shaft 126 may also be coupled to a fan spool or shaft 128 of the fan section 106. In some examples, LP shaft 126 may be directly coupled to fan shaft 128 (ie, a direct drive configuration). In an alternative configuration, LP shaft 126 may be coupled to fan shaft 128 via reduction gear 130 (eg, an indirect drive or geared configuration).

[0026] like Figure 1 As shown, fan section 106 includes a plurality of fan blades 132 coupled to and extending radially outward from fan shaft 128. An annular fan casing or nacelle 134 circumferentially surrounds fan section 106 and / or at least a portion of core turbine 104. Nacelle 134 is supported relative to core turbine 104 by a plurality of circumferentially spaced outlet guide vanes 136. In addition, a downstream section 138 of nacelle 134 may surround an outer portion of core turbine 104 to define a bypass airflow passage 140 therebetween.

[0027] like Figure 1As shown, air 142 enters an inlet portion 144 of the turbofan engine 100 during operation of the turbofan engine 100. A first portion 146 of the air 142 flows into the bypass flow passage 140, while a second portion 148 of the air 142 flows into the inlet 110 of the LP compressor 112. One or more successive stages of LP compressor stator vanes 150 and LP compressor rotor blades 152 coupled to the LP shaft 126 progressively compress the second portion 148 of the air 142 flowing through the LP compressor 112 to be directed to the HP compressor 114. Next, one or more successive stages of HP compressor stator vanes 154 and HP compressor rotor blades 156 coupled to the HP shaft 124 further compress the second portion 148 of the air 142 flowing through the HP compressor 114. This provides the compressed air 158 to the combustion section 116, where it is mixed with fuel and combusted to provide combustion gases 160.

[0028] The combustion gases 160 flow through the HP turbine 118, where one or more successive stages of HP turbine stator blades 162 and HP turbine rotor blades 164 coupled to the HP shaft 124 extract a first portion of kinetic and / or thermal energy from the combustion gases 160. This energy extraction supports the operation of the HP compressor 114. The combustion gases 160 then flow through the LP turbine 120, where one or more successive stages of LP turbine stator blades 166 and LP turbine rotor blades 168 coupled to the LP shaft 126 extract a second portion of thermal and / or kinetic energy therefrom. This energy extraction causes the LP shaft 126 to rotate, thereby supporting the operation of the LP compressor 112 and / or the rotation of the fan shaft 128. The combustion gases 160 then exit the core turbine 104 through the exhaust section 122 of the core turbine 104.

[0029] As with the turbofan engine 100, the core turbine 104 is used for similar purposes and sees similar environments in land-based gas turbines, turbojets, and non-ducted fan engines, where the ratio of the first portion 146 of air 142 to the second portion 148 of air 142 is less than that of the turbofan engine, and where the fan section 106 does not have a nacelle 134. In each of the turbofan engine, turbojets, and non-ducted engines, a speed reduction device (e.g., a speed reduction gearbox 130) may be included between any shaft and the spool. For example, the speed reduction gearbox 130 may be disposed between the LP shaft 126 and the fan shaft 128 of the fan section 106.

[0030] Figure 2 Shows Figure 1 An example cross-sectional side view of an HP compressor 114 of a turbofan engine 100 is shown. The HP compressor 114 includes one or more consecutive stages. Figure 2 The illustrated example includes a first stage 206, a second stage 208 axially downstream of the first stage 206, a third stage 210 axially downstream of the second stage 208, and a fourth stage 212 axially downstream of the third stage 210. However, the HP compressor 114 may include more or fewer stages as needed or desired.

[0031] Each of the stages 206, 208, 210, 212 includes a row 214 of stator vanes 202 and a row 216 of rotor blades 204. The stator vanes 202 in row 214 are circumferentially spaced apart. In the examples disclosed herein, the stator vanes 202 are variable stator vanes ("VSV 202"), which may be coupled to one or more synchronizing rings or brackets, for example. The synchronizing rings or brackets are coupled to an actuator to rotate the VSV 202 at least partially about a radial axis. For example, the VSV 202 is coupled to a VSV lever arm 230. In the examples disclosed herein, the VSV 202 may rotate about an axis in a radial direction R to mitigate compressor stall or surge. Each VSV 202 includes a trunnion 227 to couple with a corresponding inner shroud 226. In Figure 2 In the example shown, the trunnion 227 is disposed radially inwardly from the engine case 232. Figure 2 In the example shown, inner shroud 226 is coupled to a sealed box 228 .

[0032] Similarly, rotor blades 204 in row 216 are also circumferentially spaced apart. Figure 2 In the example shown, the row 216 of rotor blades 204 is positioned axially downstream of the row 214 of stator vanes 202. Each rotor blade 204 includes a connection portion 234 (not labeled relative to the rotor blades 204 of stages 208, 210, 212) extending radially inward from the engine case 232 for coupling with a corresponding rotor disk 218. The connection portion may include an axial dovetail, a circumferential dovetail, a fir tree, or other connection portion shape.

[0033] The rows 214 of the stator blades 202 and the rows 216 of the rotor blades 204 of each of the stages 206, 208, 210, 212 collectively define a compressed gas path 222 through which the second portion 148 of the air 142 flows. In particular, the stator blades 202 direct the second portion 222 of the air 142 onto the rotor blades 204, which imparts kinetic energy to the second portion 148 of the air 142. In this regard, the rotor blades 204 convert the second portion 148 of the air 142 flowing through the HP compressor 114 into the compressed air 158. If the exit guide vanes are included, the exit guide vanes direct the compressed air flow 158 into the combustion section 116.

[0034] A coupling, such as a labyrinth seal 224, is located between each pair of adjacent rotor disks 218. For example, Figure 2 In the example shown, the first labyrinth seal 224 is located between the rotor disks 218 of the first and second stages 206, 208. The second labyrinth seal 224 is located between the rotor disks 218 of the second and third stages 208, 210. The third labyrinth seal 224 is located between the rotor disks 218 of the third and fourth stages 210, 212. The fourth labyrinth seal 224 is axially positioned downstream of the rotor disk 218 of the fourth stage 212. The labyrinth seal 224 prevents interstage leakage of the second portion 148 of the air 142 across the compressor stages 206, 208, 210, 212. In addition, the labyrinth seal 224 allows relative rotation between each row 214 of the stator vanes 202 and the adjacent rotor disk 218. This allows the rotor blades 204 to rotate while the stator vanes 202 remain stationary. In other examples, the coupling may be a brush seal (not shown) or any type of suitable seal. In this regard, when the HP turbine 118 drives the HP shaft 124 , all of the rotor disks 218 rotate in unison. Furthermore, each of the labyrinth seals 224 is coupled with each corresponding pair of adjacent rotor disks 218 , thereby defining a rotor disk space 220 .

[0035] Figure 3 An example perspective view of a first example split shroud 300 is illustrated. Figure 3 Examples of graphics include Figure 1 and Figure 2 1 is a perspective view of a cross-sectional side view of the HP compressor 114. The HP compressor 114 includes a VSV 202 of a row 214 of a second stage 208. However, rows 214 of stages 206, 210, 212 may additionally or alternatively be included. Figure 3 Only one VSV 202 is shown in FIG. 1 , but it should be understood that one or more VSVs 202 may be included. The HP compressor 114 includes an inner shroud 226 implemented by a split shroud 300 coupled to a seal box 228 .

[0036] The split shroud 300 includes a VSV 202 coupled to the split shroud 300 via a trunnion 227. That is, the trunnion 227 engages with an opening 302 in the split shroud 300. Figure 3In the illustrated example of , the split shroud 300 includes 16 openings 302 (e.g., corresponding to 16 VSVs 202 (not shown)). The split shroud 300 includes a first front shroud segment 304, a second front shroud segment 306, and a third front shroud segment 308. The split shroud 300 also includes a first rear shroud segment 310, a second rear shroud segment 312, and a third rear shroud segment 314. That is, the rear shroud segments 310, 312, 314 are located axially downstream of the front shroud segments 304, 306, 308. The shroud segments 304, 306, 308, 310, 312, 314 can be any material suitable for the environment and compatible with the shroud and damping system. In some examples, the shroud segments 304, 306, 308, 310, 312, 314 are steel. However, the shroud segments 304 , 306 , 308 , 310 , 312 , 314 may additionally or alternatively be titanium, iron, or nickel alloys having sufficient strength, fatigue resistance, and / or other material properties, etc., for vibration damping.

[0037] In the examples disclosed herein, the shroud segments 304, 306, 308, 310, 312, 314 of the split shroud 300 provide mass damping and mis-tuning behavior during engine operation. That is, the mis-tuning of the shroud segments 304, 306, 308, 310, 312, 314 can help damp and / or reduce component vibration. For example, the shroud segments 304, 306, 308, 310, 312, 314 act as anti-modes to certain vibration responses. That is, the VSV 202 vibrates at a first frequency during normal engine operation based on the design parameters of the VSV 202 (e.g., durability, stiffness, etc.). The shroud segments 304, 306, 308, 310, 312, 314 can be tuned (e.g., designed to have a certain durability, stiffness, weight, etc.) to vibrate at a second frequency during normal engine operation, so that the second frequency interferes with the first frequency. That is, the shroud segments 304, 306, 308, 310, 312, 314 may be tuned to act anti-mode to the vibrations of the gas turbine engine 100. Thus, the shroud segments 304, 306, 308, 310, 312, 314 provide vibration reduction from damping, detuning damping, or detuning alone.

[0038] For example, the gas turbine engine 100 may vibrate at a first frequency of 10 Hz. The shroud segments 304, 306, 308, 310, 312, 314 may be tuned to vibrate at a second frequency that is an integral of a non-system response, such as 13 Hz or 14 Hz. The vibration of the shroud segments 304, 306, 308, 310, 312, 314 interferes with the vibration of the VSV 202, and thus suppresses the vibration of the VSV 202 and reduces trunnion cracking. In some examples, the shroud segments 304, 306, 308, 310, 312, 314 are tuned to vibrate at the same frequency. Additionally or alternatively, the shroud segments 304, 306, 308, 310, 312, 314 are tuned to vibrate at different frequencies. At least the front shroud segments 304, 306, 308 may be used to implement a first device for detuning and damping component vibration. At least the rear shroud segments 310, 312, 314 may be used to implement a second means for detuning and damping component vibrations.

[0039] In the illustrated example, the shroud segments 304, 306, 308, 310, 312, 314 are coupled via pins. However, the shroud segments 304, 306, 308, 310, 312, 314 may be coupled by bolts, screws, etc. For example, the first front shroud segment 304 is bolted to the second front shroud segment 306 and the first rear shroud segment 310. Additionally or alternatively, the shroud segments 304, 306, 308, 310, 312, 314 may be tilted apart so that the shroud segments are locked together. In the examples disclosed herein, friction damping between the shroud segments 304, 306, 308, 310, 312, 314 reduces movement (e.g., vibration) of the shroud segments 304, 306, 308, 310, 312, 314 during the vibration mode response.

[0040] exist Figure 3 In the example shown, the forward shroud segments 304, 306, 308 have a first axial length 316, and the aft shroud segments 310, 312, 314 have a second axial length 318. The first axial length 316 is shorter than the second axial length 318. That is, the forward shroud segments 304, 306, 308 are not symmetrical with the aft shroud segments 310, 312, 314. However, in some examples, the first axial length 316 may be longer than or equal to the second axial length 318.

[0041] Figure 4A An example top view of a second example split shroud 400 is illustrated. The second split shroud 400 includes a first front shroud segment 402, a second front shroud segment 404, and a third front shroud segment 406. The second split shroud 400 also includes a first rear shroud segment 408, a second rear shroud segment 410, a third rear shroud segment 412, and a fourth rear shroud segment 414. Figure 4AIn the example shown, the shroud segments 404, 410, 412 have equal circumferences. However, in some examples, the shroud segments 402, 404, 406, 408, 410, 412, 414 have unequal circumferences.

[0042] exist Figure 4A In the example shown, the first front shield segment 402 is bolted to the second front shield segment 404 to form a first dividing line 403. The second front shield segment 404 is bolted to the third front shield segment 406 to form a second dividing line 405. The first rear shield segment 408 is bolted to the second rear shield segment 410 to form a third dividing line 409. The second rear shield segment 410 is bolted to the third rear shield segment 412 to form a fourth dividing line 411. The third rear shield segment 412 is bolted to the fourth rear shield segment 414 to form a fifth dividing line 413. The front shield segments 402, 404, 406 and the rear shield segments 408, 410, 412, 414 form a sixth dividing line 415. Figure 4A In the example shown, the dividing lines 403 , 405 , 409 , 411 , 413 are parallel to the axial axis, that is, the dividing lines 403 , 405 , 409 , 411 , 413 are perpendicular to the sixth dividing line 415 .

[0043] exist Figure 4A In the example shown, the forward shroud segments 402, 404, 406 have a first axial length 416 and the aft shroud segments 408, 410, 412, 414 have a second axial length 418. The first axial length 416 is equal to the second axial length 418. However, in some examples, the first axial length 416 may be longer or shorter than the second axial length 418.

[0044] Figure 4B An example top view of a third example split shroud 450 is illustrated. The third split shroud 450 includes a first front shroud segment 452, a second front shroud segment 454, a third front shroud segment 456, and a fourth front shroud segment 458. The third split shroud 450 also includes a first rear shroud segment 460, a second rear shroud segment 462, a third rear shroud segment 464, and a fourth rear shroud segment 466.

[0045] exist Figure 4BIn the example shown, the first front shield segment 452 is bolted to the second front shield segment 454 to form a first dividing line 453. The second front shield segment 454 is bolted to the third front shield segment 456 to form a second dividing line 455. The third front shield segment 456 is bolted to the fourth front shield segment 458 to form a third dividing line 457. The first rear shield segment 460 is bolted to the second rear shield segment 462 to form a fourth dividing line 461. The second rear shield segment 462 is bolted to the third rear shield segment 464 to form a fifth dividing line 463. The third rear shield segment 464 is bolted to the fourth rear shield segment 466 to form a sixth dividing line 465. The front shield segments 452, 454, 456, 458 and the rear shield segments 460, 462, 464, 466 form a seventh dividing line 467. Figure 4A In the example shown, the dividing lines 453, 455, 457, 461, 463, 465 are not parallel to the axial axis. In other words, the dividing lines 453, 455, 457, 461, 463, 465 are not perpendicular to the seventh dividing line.

[0046] exist Figure 4B In the example shown, the forward shroud segments 452, 454, 456, 458 have a first axial length 468, while the aft shroud segments 460, 462, 464, 466 have a second axial length 470. The first axial length 468 is equal to the second axial length 470. However, in some examples, the first axial length 468 may be longer or shorter than the second axial length 470.

[0047] Split shroud 300, split shroud 400, and / or split shroud 450 may prevent and / or reduce strain caused by engine vibrations of VSV 202 during normal engine operation. Reduction / prevention of engine vibrations increases the reliability of VSV 202 and the durability of VSV 202. For example, improved reliability / durability of VSV 202 may reduce the risk of stall due to blade locking. Additionally or alternatively, split shroud 300, split shroud 400, and / or split shroud 450 may reduce weight, cost, etc. of gas turbine engine 100.

[0048] In operation, the split shroud (e.g., split shroud 300, split shroud 400, and / or split shroud 450) coupled to the seal box 228 provides detuning and / or damping to act in an anti-mode manner on vibrations generated by the gas turbine engine 100. That is, the examples disclosed herein improve the reliability / durability of the gas turbine engine by reducing vibrations of the gas turbine engine (e.g., vibrations of one or more airfoils, etc.). In some examples, the split shroud reduces component vibrations, which reduces deformation and / or strain caused by gas turbine operation.

[0049] Although certain example methods, apparatus, and articles of manufacture have been disclosed herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus, and articles of manufacture that fully fall within the scope of the claims of this patent.

[0050] Example methods, apparatus, systems, and articles of manufacture for reducing engine vibration are disclosed herein.

[0051] Further aspects of the invention are provided by the subject matter of the following clauses. Example 1 includes a split shroud for an inner shroud of a gas turbine engine, the split shroud comprising: at least one front shroud segment; and at least one rear shroud segment, the at least one rear shroud segment coupled to the at least one front shroud segment, the at least one front shroud segment and the at least one rear shroud segment forming a split line.

[0052] Example 2 includes the split shroud of any preceding clause, wherein the at least one forward shroud segment and the at least one aft shroud segment are tuned to act anti-mode to engine vibration based on at least one of durability, stiffness, or weight.

[0053] Example 3 includes the split shroud of any preceding clause, wherein the at least one forward shroud segment has a first axial length and the at least one aft shroud segment has a second axial length.

[0054] Example 4 includes the split shroud of any preceding clause, wherein the first axial length is equal to the second axial length.

[0055] Example 5 includes the split shroud of any preceding clause, wherein the first axial length is longer than the second axial length.

[0056] Example 6 includes the split shroud of any preceding clause, wherein the first axial length is shorter than the second axial length.

[0057] Example 7 includes the split shroud of any preceding clause, wherein the at least one front shroud segment is bolted to the at least one rear shroud segment.

[0058] Example 8 includes the split shroud of any preceding clause, wherein the at least one forward shroud segment and the at least one aft shroud segment form at least one opening coupling the split shroud damper to an airfoil.

[0059] Example 9 includes the split shield of any preceding clause, wherein the at least one front shield segment is a first front shield segment coupled to a second front shield segment, and the dividing line is a first dividing line, wherein the first front shield segment and the second front shield segment form a second dividing line.

[0060] Example 10 includes the split shield of any preceding clause, wherein the second dividing line is perpendicular to the first dividing line.

[0061] Example 11 includes the split shield of any preceding clause, wherein the second dividing line is not perpendicular to the first dividing line.

[0062] Example 12 includes a gas turbine engine, comprising: a split shroud, the split shroud comprising: at least one front shroud segment; and at least one rear shroud segment, the at least one rear shroud segment being connected to the at least one front shroud segment, the at least one front shroud segment and the at least one rear shroud segment forming a dividing line; and a sealing box, the sealing box being connected to the at least one front shroud segment and the at least one rear shroud segment.

[0063] Example 13 includes the gas turbine engine of any preceding clause, wherein the at least one forward shroud segment and the at least one aft shroud segment are tuned to act anti-mode to engine vibration based on at least one of durability, stiffness, or weight.

[0064] Example 14 includes the gas turbine engine of any preceding clause, wherein the at least one forward shroud segment has a first axial length and the at least one aft shroud segment has a second axial length.

[0065] Example 15 includes the gas turbine engine of any preceding clause, wherein the first axial length is equal to, longer than, or shorter than the second axial length.

[0066] Example 16 includes the gas turbine engine of any preceding clause, wherein the at least one forward shroud segment is bolted to the at least one aft shroud segment.

[0067] Example 17 includes the gas turbine engine of any preceding clause, wherein the at least one forward shroud segment and the at least one aft shroud segment form at least one opening coupling the split shroud damper to an airfoil.

[0068] Example 18 includes a gas turbine engine according to any of the preceding clauses, wherein the at least one forward shroud segment is a first forward shroud segment coupled to a second forward shroud segment, and the dividing line is a first dividing line, wherein the first forward shroud segment and the second forward shroud segment form a second dividing line.

[0069] Example 19 includes the gas turbine engine of any preceding clause, wherein the second dividing line is perpendicular to the first dividing line.

[0070] Example 20 includes a split shroud damper for a gas turbine engine, the split shroud damper comprising: a first device for detuning and damping component vibrations; and a second device for detuning and damping component vibrations, the second device for detuning and damping component vibrations being coupled to the first device for detuning and damping component vibrations.

[0071] The following claims are hereby incorporated into the Detailed Description by reference, with each claim standing on its own as a separate embodiment of the present disclosure.

Claims

1. A split shroud for an inner shroud of a gas turbine engine, characterized in that: The split shield comprises: at least a first front shroud segment, a second front shroud segment, and a third front shroud segment; and At least one rear shroud segment is connected to the first front shroud segment, the first front shroud segment and the at least one rear shroud segment form a first dividing line, the first front shroud segment and the second front shroud segment form a second dividing line, and the second front shroud segment and the third front shroud segment form a third dividing line, wherein, during operation of the gas turbine engine, the first front shroud segment vibrates at a first frequency, the second front shroud segment vibrates at a second frequency, the third front shroud segment vibrates at a third frequency, and the rear shroud segment vibrates at a fourth frequency.

2. The split type shield according to claim 1, characterized in that: Wherein the at least first, second and third front shroud segments and the at least one rear shroud segment are tuned to act anti-mode to engine vibrations based on at least one of durability, stiffness or weight.

3. The split type shield according to claim 1, characterized in that: Wherein the first forward shroud segment has a first axial length and the at least one rearward shroud segment has a second axial length.

4. The split type shield according to claim 3, characterized in that: Wherein the first axial length is equal to the second axial length.

5. The split type shield according to claim 3, characterized in that: The first axial length is longer than the second axial length.

6. The split type shield according to claim 3, characterized in that: The first axial length is shorter than the second axial length.

7. The split type shield according to claim 1, characterized in that: Wherein the first front shroud segment is bolted to the at least one rear shroud segment.

8. The split type shield according to claim 1, characterized in that: Wherein the first forward shroud segment and the at least one aft shroud segment form at least one opening, the at least one opening coupling the split shroud to the airfoil.

9. The split shield according to claim 1, characterized in that: The second cutting line is perpendicular to the first cutting line.

10. The split type shield according to claim 1, characterized in that: The second cutting line is not perpendicular to the first cutting line.

11. A gas turbine engine, characterized in that: include: A split shield, the split shield comprising: at least a first front shroud segment, a second front shroud segment, and a third front shroud segment; and at least one aft shroud segment, the at least one aft shroud segment being coupled to the first forward shroud segment, the first forward shroud segment and the at least one aft shroud segment forming a first dividing line, the first forward shroud segment and the second forward shroud segment forming a second dividing line, the second forward shroud segment and the third forward shroud segment forming a third dividing line, wherein during operation of the gas turbine engine, the first forward shroud segment vibrates at a first frequency, the second forward shroud segment vibrates at a second frequency, the third forward shroud segment vibrates at a third frequency, and the aft shroud segment vibrates at a fourth frequency; and A sealing box is coupled to the first, second, and third front shroud segments and the at least one rear shroud segment.

12. The gas turbine engine according to claim 11, characterized in that Wherein at least the first, second and third front shroud segments and the at least one rear shroud segment are tuned to act anti-mode to engine vibration based on at least one of durability, stiffness or weight.

13. The gas turbine engine according to claim 11, characterized in that Wherein the first forward shroud segment has a first axial length and the at least one rearward shroud segment has a second axial length.

14. The gas turbine engine according to claim 13, characterized in that The first axial length is equal to the second axial length, longer than the second axial length, or shorter than the second axial length.

15. The gas turbine engine according to claim 11, characterized in that Wherein the first front shroud segment is bolted to the at least one rear shroud segment.

16. The gas turbine engine according to claim 11, characterized in that Wherein the first forward shroud segment and the at least one aft shroud segment form at least one opening, the at least one opening coupling the split shroud to the airfoil.

17. The gas turbine engine according to claim 11, characterized in that The second cutting line is perpendicular to the first cutting line.

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