Vibration damping system for turbomachinery blades on a spacer adjacent to a blade stage - Patents.com

Abstract

To provide a vibration-damping system for turbine blades in a turbine.SOLUTION: Each turbine blade 114 includes a platform 136 having a radially inner surface 137. A system 128 includes a spacer 150 axially adjacent to the platform of at least one turbine blade in the turbine, e.g., adjacent to a turbine blade stage. The spacer includes a body 154 with a gas path-facing surface 156 forming a portion of an annulus for a working fluid flow path. A damping element coupler 162 is on the body of the spacer, and a vibration-damping element 164 is configured to couple to the damping element coupler. The vibration-damping element and the damping element coupler are disposed to cause the vibration-damping element to engage the radially inner surface of the platform of the turbine blades to dampen vibration of the turbine blades during operation of the turbine.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] This disclosure relates generally to vibration damping in industrial machines, and more particularly to damping blades used in turbomachines using a vibration damping system coupled to a spacer adjacent a blade stage. [Background technology]

[0002] One concern in turbomachinery operation is the tendency of blades to experience vibratory stresses during operation. In many installations, turbomachinery is operated under conditions of frequent acceleration and deceleration. During acceleration or deceleration of the turbomachinery, the blades are exposed, at least momentarily, to vibratory stresses at specific frequencies, often at secondary or tertiary frequencies. Blades may also vibrate during steady-state operation. When blades are exposed to vibratory stresses, the amplitude of the vibrations can easily increase to a point that could alter operation.

[0003] In one example, a compressor in an axial turbomachine system typically includes a rotor assembly comprising a rotor disk and a plurality of blades circumferentially arranged around the rotor disk. Each blade includes a base (or root), an airfoil, and a platform positioned in a transition area between the base and the airfoil. The blade base is received in a complementary shaped recess in the rotor disk. The blade platforms extend laterally outward and collectively form a flowpath for the working fluid passing through the rotor stage. The forward edge of each blade is commonly referred to as the leading edge, and the aft edge is referred to as the trailing edge. "Forward" is defined as upstream of "aft" for gas flow through the system.

[0004] During operation, blades can be excited to vibrate by several different forcing functions. For example, fluctuations in gas temperature, pressure, and / or density can excite vibrations throughout the rotor assembly, particularly within the blade airfoils. The gases experience periodic or "pulsating" flows that can also excite undesirable vibrations.

[0005] Blades can be damped against vibration in several ways. Current approaches can be categorized as single-blade, blade-to-blade, blade-to-rotor-disk, and passive approaches. In a single-blade approach, a damper can be attached to the exterior surface of the airfoil. A recognized drawback of adding a damper to the exterior surface is that it exposes the damper to the harsh and corrosive environment within the engine. As soon as the damper begins to corrode, its effectiveness can be compromised. Additionally, corrosion can cause the damper to detach from the airfoil. With the blade-to-blade approach, various physical structures of the blade can be altered to stiffen the blade against vibration. For example, a mid-span shroud can be used to connect adjacent blades. Modifying or adding structures to the blade creates additional challenges by changing the blade's aerodynamic performance and adding weight and / or length. Blades can also be damped by structures that engage the platform of adjacent blades, such as damping pins. Single-blade and blade-to-blade approaches may not provide grounding for vibration, which significantly reduces the damper's effectiveness during in-phase vibration response.

[0006] Blades may also be damped using a blade-to-rotor disk approach, where a damping element engages the underside of the platform or shank of an adjacent blade. The damping element is then bonded to the rotor disk. These arrangements are typically very complex to install and / or repair, as they must fit between the shanks and / or platforms of adjacent blades.

[0007] Mechanisms have also been employed to passively absorb pressures that cause vibrations during use. In one example, a cavity, or in another example, a baffle, may be provided adjacent the outer tip of the blade to absorb pressure fluctuations during operation. In another case, a high-pressure airflow may be directed from an upstream location to the leading edge of the blade stage. Summary of the Invention

[0008] A first aspect of the present disclosure provides a vibration damping system for at least one turbomachine blade in a turbomachine, each turbomachine blade having a platform with a radially inner surface, the system including a spacer axially adjacent the platform of the at least one turbomachine blade in the turbomachine, and a vibration damping system positioned on a body of the spacer. vibration a damping element coupler; vibration a vibration damping element configured to couple to the damping element coupler, vibration The damping element coupler is positioned to engage the vibration damping element with a radially inner surface of the platform of the at least one turbomachine blade to damp vibration of the at least one turbomachine blade.

[0009] A second aspect of the present disclosure provides a spacer for positioning adjacent a turbomachine blade stage in a turbomachine, the spacer including a body, a dovetail on the body, and a vibration-damping element coupler on the body, the vibration-damping element coupler arranged to position the vibration-damping element to engage a radially inner surface of a platform of at least one turbomachine blade in the turbomachine blade stage and to damp vibration of the at least one turbomachine blade.

[0010] A third aspect of the present disclosure provides a vibration damping element for a pair of circumferentially adjacent turbomachine blades in a turbomachine, each turbomachine blade having a platform with a radially inner surface, the vibration damping element comprising a U-shaped body having first and second legs extending from a base portion connecting the first and second legs, the U-shaped body being disposed on a body of a spacer axially adjacent the pair of circumferentially adjacent turbomachine blades in the turbomachine. vibrationThe damping element coupler has a U-shaped body defining a receiver for coupling the U-shaped body to the damping element coupler, and a first bearing surface on the base portion configured to engage a radially inner surface of each turbomachine blade, the first bearing surface being oriented at a non-parallel angle relative to a rotor axis of the turbomachine.

[0011] A fourth aspect of the present disclosure includes a method including coupling a vibration-damping element to a body of a spacer axially adjacent a pair of circumferentially adjacent turbomachine blades in a turbomachine, the vibration-damping element extending adjacent a radially inner surface of each platform of the pair of circumferentially adjacent turbomachine blades, and during operation of the turbomachine, damping vibration of the pair of circumferentially adjacent turbomachine blades by engaging the vibration-damping element with the radially inner surface of each platform of the pair of circumferentially adjacent turbomachine blades and engaging the vibration-damping element with the body of the spacer axially adjacent the pair of circumferentially adjacent turbomachine blades.

[0012] The exemplary aspects of the present disclosure are designed to solve the problems described herein and / or other problems not discussed.

[0013] These and other features of the present disclosure will be more readily understood from the following detailed description of the various aspects of the disclosure, taken in conjunction with the accompanying drawings which illustrate various embodiments of the present disclosure. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic illustration of an exemplary turbomachine in the form of a gas turbine system; [Figure 2] FIG. 1 is a cross-sectional view of a portion of an exemplary compressor according to an embodiment of the present disclosure. [Figure 3] 1 is a perspective view of an exemplary turbomachine blade according to an embodiment of the present disclosure; [Figure 4] 1 is a circumferential side view of a vibration damping system for a turbomachine blade according to an embodiment of the present disclosure; [Figure 5]FIG. 1 is a perspective view of a blade with a vibration damping system according to an embodiment of the present disclosure. [Figure 6] FIG. 1 is an enlarged perspective view of a blade with a vibration damping system according to an embodiment of the present disclosure. [Figure 7] FIG. 10 is an enlarged end view of a vibration damping element according to an embodiment of the present disclosure. [Figure 8] FIG. 1 is an enlarged perspective view of a spacer according to an embodiment of the present disclosure. [Figure 9] FIG. 10 is an enlarged perspective view of a spacer according to another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] It should be noted that the drawings of the present disclosure are not necessarily to scale. The drawings are intended to depict only typical aspects of the present disclosure and therefore should not be considered limiting of the scope of the present disclosure. In the drawings, like numbers represent like elements between the drawings.

[0016] As an initial matter, in order to clearly explain the subject matter of this disclosure, it becomes necessary to select specific terminology when referring to and describing relevant machine components within turbomachinery. In doing so, wherever possible, common industry terminology will be used and utilized consistent with its accepted meaning. Unless otherwise noted, such terminology should be given a broad interpretation consistent with the context of this application and the scope of the appended claims. Those skilled in the art will recognize that in many cases, a particular component may be referred to using several different or overlapping terms. What may be described herein as being a single component may include, and be referred to in other contexts as consisting of multiple components. Alternatively, what may be described herein as comprising multiple components may be referred to elsewhere as a single component.

[0017] Additionally, several descriptive terms may be used regularly herein, and it will prove useful to define these terms at the beginning of this section. These terms and their definitions are as follows, unless otherwise stated: As used herein, "downstream" and "upstream" are terms that indicate a direction relative to the flow of a working fluid through a turbomachine, or a fluid, such as, for example, the flow of air through a combustor, or a coolant through one of the turbomachine's component systems. The term "downstream" corresponds to the direction of fluid flow, and the term "upstream" refers to the opposite direction of flow. It is recognized that in counter-flow configurations, the upstream and downstream directions may change depending on where in the turbomachine one is located. The terms "forward" and "aft" refer to directions, unless otherwise specified, with "forward" referring to the front end of the turbomachine and "aft" referring to the rear section of the turbomachine.

[0018] It is often desired to describe components at different radial locations relative to a central axis. The term "radial" refers to movement or position perpendicular to the axis. In such cases, if a first component is located closer to the axis than a second component, the first component may be described herein as being "radially inward" or "inward" of the second component. Conversely, if a first component is located farther from the axis than the second component, the first component may be described herein as being "radially outward" or "outward" of the second component. The term "axial" refers to movement or position parallel to the axis. Finally, the term "circumferential" refers to movement or position around the axis. It will be understood that such terms may be applied with respect to the central axis of a turbomachinery system, e.g., the axis of its rotor.

[0019] Additionally, as noted below, certain descriptive terms may be used herein in a conventional manner: the terms "first," "second," and "third" may be used interchangeably to distinguish one component from another, and are not intended to denote the location or importance of the individual components.

[0020] Embodiments of the present disclosure provide, among other things, a vibration damping system for turbomachine blades in a turbomachine, e.g., a compressor. Each turbomachine blade includes a platform having a radially inner surface. The system includes a spacer axially adjacent the platform of at least one turbomachine blade in the turbomachine, e.g., adjacent a turbomachine blade stage. The spacer includes a body and includes a gaspath-facing surface that forms a portion of an annulus for a working fluid flowpath. vibration A damping element coupler is positioned on the body of the spacer, and the vibration damping element is vibration The damping element is configured to couple to the coupler. vibration The damping element coupler is positioned to engage the vibration damping element with a radially inner surface of the platform of the turbomachine blade, i.e., to damp vibration of the turbomachine blade during operation of the turbomachine. The vibration damping element frictionally damps vibration of the turbomachine blade and damps vibration through the spacer to the ground through to the rotor disk. The vibration damping system can also frictionally damp vibration between adjacent blades for out-of-phase vibration response. The vibration damping system including the vibration damping element reduces blade vibration with simple deployment and does not require changes to the blade configuration.

[0021] Referring to the drawings, FIG. 1 is a schematic diagram of an exemplary turbomachine to which the teachings of the present disclosure may be applied. Shown in FIG. 1 is a turbomachine 90 in the form of a combustion turbine or gas turbine (GT) system 100 (hereinafter, "GT system 100"). GT system 100 includes a compressor 102 and a combustor 104. Combustor 104 includes a combustion region 105 and a fuel nozzle section 106. GT system 100 also includes a turbine 108 and a common compressor / turbine shaft 110 (hereinafter, "rotor 110"). The present disclosure is not limited to any particular GT system and may be implemented in connection with other engines, including, for example, other General Electric HA, F, B, LM, GT, TM, and E-class engine models, as well as engine models from other manufacturers. Although embodiments of the present disclosure are described with respect to turbomachine blades in the form of compressor blades in compressor 102, the teachings of the present disclosure are not necessarily applicable only to compressors, but indeed may be applied to any type of turbomachine or turbomachine section, e.g., steam turbines, jet engines, gas turbines (such as 108 in FIG. 1), turbofans, turbochargers, etc. Thus, reference to compressor 102 is merely illustrative and not limiting.

[0022] FIG. 2 illustrates a cross-sectional view of an exemplary portion of the axial compressor 102 of the turbomachine 90 (FIG. 1). In the illustrated example, the compressor 102 includes four compressor blade stages S1-S4 arranged along an axis A, i.e., the axis of the rotor 110. Each compressor blade stage includes a plurality of compressor blades 114 (hereinafter, "blades 114") circumferentially attached to the rotor 110 by a rotor disk 116. That is, the blades 114 of each stage are mechanically coupled to the rotor 110 by a respective rotor disk 116. The rotor disk 116 couples the blades to the rotor 110 in a circumferentially spaced-apart relationship. The four stages are designated S1, S2, S3, and S4. Stage 1 is the first stage and is the largest (radially) of the four stages. Stage 2 is the second stage and is the axially next stage. Stage 3 is the third stage and is the axially next stage. Stage 4 is the fourth and final stage and is the smallest (radially) stage. It should be understood that four stages is shown by way of example only, and that each turbomachine may have more or less than four stages.

[0023] A stage may include only rotary compressor blades 114, or as shown, a plurality of stationary vanes or vanes 112 may cooperate with the compressor blades 114 to form each of stages 1-4 of the turbomachine 90 (FIG. 1) and define a portion of the working fluid flowpath through the turbomachine 90 (FIG. 1). A static vane section 115 includes a plurality of stationary vanes 112 spaced circumferentially around the rotor 110 and coupled to a static casing 124. A spacer 150 (having a body) may be located adjacent a blade stage, e.g., stage 1 and / or stage 2 in the example shown in FIG. 2. As described herein, each spacer 150 is axially adjacent to a platform of a blade 114 in the turbomachine 90. The spacers 150 may simply be positioned between platforms 136 (FIG. 3) or may include a gaspath-facing surface that forms part of an annulus for the working fluid flowpath through the turbomachine 90. The spacers 150 need not be adjacent to each stage of blades 114.

[0024] During operation, rotor disk 116 and blades 114 rotate about axis A of compressor 102 while stator vanes 112 remain stationary. In this manner, blades 114 cooperate with adjacent stator vanes 112 to impart kinetic energy to and compress an incoming flow of air 120, which is then delivered to combustor 104 (FIG. 1). Other types of compressor configurations may also be used.

[0025] 1 and 2 , during operation, air flows through the compressor 102, and the compressed air is supplied to the combustor 104. Specifically, the compressed air is supplied to a fuel nozzle section 106 integrated with the combustor 104. The fuel nozzle section 106 is in flow communication with a combustion zone 105. The fuel nozzle section 106 is also in flow communication with a fuel source (not shown in FIG. 1 ) and delivers fuel and air to the combustion zone 105. The combustor 104 ignites and combusts the fuel. The combustor 104 is in flow communication with a turbine 108, in which thermal energy of the gas stream is converted to mechanical rotational energy by directing the combusted fuel, e.g., a working fluid, into a working fluid flowpath to rotate blades 114. The vanes 112, and spacers 150 (if provided), define the working fluid flowpath. The turbine 108 is rotatably coupled to and drives a rotor 110. Compressor 102 is rotatably coupled to rotor 110. At least one end of rotor 110 may extend axially away from turbomachine 90 and may be attached to a load or machine (not shown), such as, but not limited to, an electrical generator, a load compressor, and / or another turbine.

[0026] FIG. 3 shows a perspective view of a type of blade 114 that may employ an embodiment of a vibration-damping system 128 (FIG. 4) of the present disclosure. Each of the plurality of blades 114 may include a root or base 130 at which the blade 114 is attached to the rotor 110 (FIG. 1) using a rotor disk 116 (FIG. 2). The base 130 may include a dovetail 132 configured to fit into a corresponding dovetail slot around the periphery of the rotor disk 116 (FIGS. 2 and 4) of the rotor 110 (FIG. 1). The base 130 may further include a shank 134 extending between the dovetail 132 and a platform 136, which is disposed at the junction of the airfoil body 138 and the base 130 and defines a portion of the inner boundary of the working fluid flowpath (FIG. 2) through the turbomachine 90. Each platform 136 includes a radially inner surface 137 and a radially outer (gaspath-facing) surface 139.

[0027] It will be appreciated that the airfoil body 138 is the active component of the blade 114 that interrupts the flow of the working fluid. It will be seen that the airfoil body 138 of the blade 114 may include a concave pressure side (PS) outer wall 140 and a circumferentially or laterally opposed convex suction side (SS) outer wall 142 that extend axially between opposing leading and trailing edges 144 and 146, respectively. The sidewalls 140 and 142 also extend radially from the platform 136 to an outer tip 148. Thus, the airfoil body 138 extends from the platform 136 to the outer tip 148. The blade 114 may also include a part-span shroud (not shown) extending from each outer wall 140, 142. As will be appreciated, the part-span shroud may be located along the radial span of the blade 114 and may interact or interlock with the part-span shroud of an adjacent blade to, among other things, reduce vibration of each blade 114. Although exemplary blades 114 have been described, it will be appreciated that blades may vary in construction across different types of turbomachines.

[0028] As described above, during turbomachine operation, blades 114 may be excited to vibrate by a number of different forcing functions. For example, fluctuations in the temperature, pressure, and / or density of the working fluid may excite vibrations throughout the rotor assembly, particularly within the blade airfoils 138 and / or outer tips 148. Gases exiting upstream of the turbine and / or compressor sections in a cyclical or "pulsating" manner may also excite undesirable vibrations. Embodiments of the present disclosure are directed to reducing vibrations in large rotating turbomachine blades 114 without significantly modifying the blade's physical structure.

[0029] FIG. 4 illustrates a circumferential side view of a vibration damping system 128 (hereinafter “system 128”) for at least one turbomachine blade 114 in turbomachine 90, e.g., a compressor blade in compressor 102. FIG. 5 illustrates a perspective view of system 128 including blade 114 and spacer 150, and FIG. 6 illustrates an enlarged perspective view thereof. As discussed above, each turbomachine blade 114 has a platform 136 including a radially inner surface 137. In one example, as best shown in the axial view without spacer 150 of FIG. 7, radially inner surface 137 of platform 136A and / or 136B may be positioned in a recess 141 in platform 136. However, recess 141 may not be necessary in all cases.

[0030] The system 128 includes a spacer 150 axially adjacent a platform 136 of a turbomachine blade in the turbomachine 90, i.e., adjacent a turbomachine blade stage. The spacer 150 includes a body 154. The spacer 150 may also include a gaspath-facing surface 156 on the body 154 that forms part of an annulus (into and out of the page) for a working fluid flowpath (arrows WF). That is, the spacer 150 forms part of the annulus adjacent the platform 136 to define the working fluid flowpath WF adjacent the blade 114. The spacer 150 may also be referred to as an annulus filler. In other embodiments, the spacer 150 may not include a gaspath-facing surface 156 and may instead be positioned radially inward of the platform 136 of the blade 114. In either case, the spacer 150 may have any desired circumferential or axial extent. The spacer 150 typically does not have any structure within the working fluid flowpath. Spacer 150 may also include a dovetail 160 on body 154 for coupling to rotor disk 116 (disk shown in phantom in FIG. 4).

[0031] The system 128 according to an embodiment of the present disclosure can also include a spacer 150 having a vibration-damping element coupler 162 (hereinafter, "coupler 162") on the body 154 and a vibration-damping element 164 (hereinafter, "element 164") configured to couple to the coupler 162. As shown in Figures 4-7, the element 164 and coupler 162 are positioned to engage the element 164 with a radially inner surface 137 of a platform 136 of a turbomachine blade 114, for example, to damp vibrations of the turbomachine blade 114 during operation of the turbomachine 90 (Figure 1). The element 164 can engage a single turbomachine blade 114 (see, for example, Figures 4-6).

[0032] However, as shown in Figure 7, the element 164 typically engages a pair of circumferentially adjacent turbomachine blades 114A, 114B, where the radially inner surfaces 137 of the platforms 136A, 136B of the pair of circumferentially adjacent turbomachine blades 114A, 114B are adjacent to one another in the turbomachine 90. Here, the element 164 and vibration The damping element coupler 162 is positioned to engage the element 164 with the radially inner surface 137 of the platform 136A, 136B of each of a pair of circumferentially adjacent turbomachine blades 114A, 114B to damp vibrations of the pair of circumferentially adjacent turbomachine blades 114A, 114B. In this manner, vibrations of both blades 114A, 114B are damped simultaneously.

[0033] Element 164 and coupler 162 can take a variety of forms depending, for example, on the blades used, the shape of platform 136, the spacing between the spacer and the blade, etc. Accordingly, the specific examples illustrated and described herein should not be considered limiting, except as claimed herein.

[0034] In the embodiment shown in the enlarged perspective views of Figures 4, 6, and 8, coupler 162 may extend from axial surface 168 of body 154 of spacer 150. Axial surface 168 may be any axially facing surface of spacer 150 that is sufficiently close to blade 114. Coupler 162 may extend in any direction necessary to position element 164 at a desired location. Axial surface 168 may provide a bearing surface for engaging element 164.

[0035] In one example, as best shown in FIG. 7 , the element 164 includes a U-shaped body 170 configured to seat on the coupler 162 ( FIGS. 4-6 , 8 ). More specifically, the element 164 may include the U-shaped body 170 having a first leg 172 and a second leg 174 extending from a base portion 176 that joins the first leg 172 and the second leg 174. In this manner, the U-shaped body 170 defines a receiver 178 for coupling the U-shaped body 170 to the coupler 162 disposed on the body 154 of the spacer 150 axially adjacent to the blades 114, e.g., a pair of circumferentially adjacent turbomachine blades 114A, 114B in the turbomachine 90.

[0036] Coupler 162 can include any suitable shape for positioning element 164. For example, as shown in the enlarged perspective view of FIG. 8 , coupler 162 can include surface 169 configured to receive element 164 thereon. For example, coupler 162 can have a rounded surface shaped to complement receiver 178. Any form of holder and / or fastener can be used to hold element 164 in coupler 162. In the illustrated example, surface 169 also forms lip 171 for (axially) retaining element 164.

[0037] The element 164 may include a number of bearing surfaces that engage the blades 114 and the spacers 150 and frictionally damp vibrations through the spacers 150 to the rotor disk 116 and between the blades. For example, as best shown in FIG. 7 , the element 164 may include a (first) bearing surface 180 on the base portion 176 configured to engage the radially inner surface 137 of the platform 136 of the blade 114 to dampen blade vibrations. For example, in FIG. 7 , both radially inner surfaces 137 are engaged by the bearing surface 180. As best shown in FIG. 4 , the bearing surface 180 may be at a non-parallel angle α with respect to the rotor axis A of the turbomachine 90. The angle α may be any angle desirable to facilitate applying pressure to the radially inner surfaces 137 of the blades 114 during operation of the turbomachine 90, for example, via centrifugal force. The angle α may also assist in creating a desired axial spacing between the blades 114 and the spacers 150. The angle α may also be such that the bearing surface 180 is parallel to the rotor axis A of the turbomachine 90, if desired.

[0038] As shown in FIGS. 4 and 7 , the element 164 may also include another (second) bearing surface 182 configured to axially engage the body 154, e.g., the axial surface 168 ( FIG. 4 ) of the body 154 of the spacer 150. As best shown in FIG. 7 , the bearing surface 182 may include a radially outer surface 183 and a spaced-apart radially inner surface 184. The radially inner surface 184 may be at an end 186 of each of the first and second legs 172, 174. The radially outer surface 183 may be on the base portion 176. Each of the radially outer and inner surfaces 183, 184 of the second bearing surface 182 is configured to axially engage the body 154 of the spacer 150, e.g., to enable proper positioning of the bearing surface 182 and / or to provide additional vibration damping of the blade 114. The bearing surface 182 is configured to engage the axial surface 168 (FIG. 4) of the body 154 of the spacer 150 at a location radially inward from the radially outer bearing surface 183 .

[0039] While particular bearing surfaces are shown herein, it will be appreciated that elements 164 can have a wide variety of alternative shapes to provide different bearing surfaces. For example, all of bearing surfaces 182 of elements 164 axially facing spacer 150 may be a continuous bearing surface capable of engaging axial surface 168 of body 154. In either case, vibrations may be guided within spacer 150 and to rotor disk 116 (FIG. 4) coupled to rotor 110 (FIG. 1), i.e., gland.

[0040] Vibration damping system 128 and its components can be formed using any now known or later developed manufacturing process, such as casting, machining, and / or additive manufacturing. For example, elements 164 including coupler 162 and / or spacer 150 can be additively manufactured.

[0041] The vibration-damping system 128 can also be added or retrofitted to spacers 150 and blades 114 that are already in use but are not necessarily ready for replacement. In this case, the coupler 162 can take a variety of alternative forms, for example. For example, as shown in the enlarged perspective view of the spacer 150 in FIG. 9 , the coupler 162 can alternatively include a number of bolts 190 coupled to the body 154 of the spacer 150, e.g., the extending axial surface 168. In either case, the coupler 162 can be coupled to the body 154 in any manner. In one example, the coupler 162 can be integrally formed with the body 154 of the spacer 150, e.g., by additive manufacturing. Alternatively, the coupler 162 can be later coupled to the body 154 of the spacer 150, e.g., welded to the spacer 150, fastened to the spacer 150, threaded into the spacer 150 (see, e.g., bolts 190 in FIG. 9 ), etc. In this latter case, according to an embodiment of the present disclosure, a previously used spacer 150 can be retrofitted for use with vibration damping system 128 by adding coupler 162. If desired, but not necessary in all cases, used blade 114 can also be machined to form recess 141 (FIG. 7) in its platform 136.

[0042] A method according to an embodiment of the present disclosure may include coupling an element 164 to a body 154 of a spacer 150 axially adjacent to a blade 114, such as a pair of circumferentially adjacent blades 114A, 114B ( FIG. 7 ) in the turbomachine 90 ( FIG. 2 ). The element 164 extends adjacent to a radially inner surface 137 of each platform 136 of the blade 114, e.g., a pair of circumferentially adjacent blades 114A, 114B ( FIG. 7 ). When the turbomachine 90 is in a non-operating state, the bearing surface 180 may be spaced from the radially inner surface 137 of the platform 136 to, for example, allow for easier installation of the element 164. During operation of the turbomachine 90, damping vibration of the blade 114 is generated by engaging the element 164 with the radially inner surface 137 of each platform 136 of the blade 114 and engaging the vibration-damping element 164 with the body 154 of the spacer 150 axially adjacent to the blade 114. When the vibration damping system 128 is applied to a pair of circumferentially adjacent turbomachine blades 114A, 114B as shown in Figure 7, damping vibration of the pair of circumferentially adjacent blades 114A, 114B (Figure 7) occurs by engaging the vibration damping element 164 with the radially inner surface 137 of each platform 136A, 136B of the pair of circumferentially adjacent turbomachine blades 114A, 114B and by engaging the vibration damping element 164 with the body 154 of the spacer 150 of the axially adjacent blade 114. Here, inter-blade vibrations are damped.

[0043] It should be noted that while embodiments of the present disclosure have been described herein with respect to blades that are part of a compressor, the teachings of the present disclosure may be applied to a variety of other applications of articles including airfoils, e.g., turbine section 108 ( FIG. 1 ), jet engines, steam turbines, and other turbomachinery. Furthermore, while embodiments of the present disclosure are shown with respect to spacer 150 aft or downstream of blade 114, it will be recognized that the teachings of the present disclosure may readily be applied to blade 114 that the spacer is forward of or upstream of, for example, by mounting coupler 162 on an axially aft-facing surface of body 154 of spacer 150 rather than on axially forward-facing axial face 168.

[0044] The disclosed embodiment provides mechanical (friction) damping that spans the under-platform surface of the blade 114 and is supported by features on the adjacent spacer 150. The vibration damping system 128 functions as both an inter-blade damper and a blade-to-ground damper. As a result, the system 128 dissipates energy in the form of friction / heat from both synchronous and asynchronous stimuli, thereby reducing vibratory stresses and increasing damage tolerance. The vibration damping system 128 can reduce vibratory stresses to an acceptable level (for blades responding above acceptable levels) and / or increase damage tolerance (by further reducing vibratory stresses) for blades that already meet acceptable vibratory stress limits. The attachment method of the element 164 to the rotor disk 116 via the spacer 150 allows for simple assembly / disassembly with deterministic and repeatable contact behavior. Additionally, the geometry of the vibration damping element 164 and the under-platform interface of the blade 114 (e.g., the radially inner surface 137) can be easily modified to customize vibration damping characteristics.

[0045] As used herein throughout this specification and claims, approximation language can be applied to modify any quantitative expression that can reasonably vary without resulting in a change in the basic function involved. Thus, values ​​modified by terms such as "approximately," "about," and "substantially" are not limited to the exact value specified. In at least some instances, approximation language can correspond to the precision of the instrument used to measure the value. Throughout this specification and claims, range limitations are combinable and / or interchangeable, and unless the context and language dictate otherwise, such ranges are identified and include all subranges encompassed therein. The term "about," as applied to a particular value in a range, applies to both endpoints and can indicate + / - 10% of the stated value, unless specifically dependent on the precision of the instrument used to measure the value.

[0046] The corresponding structure, material, acts, and equivalents of all means-plus-function or step-plus-function elements in the following claims are intended to encompass any structure, material, or acts for performing that function in combination with other specifically claimed claim elements. The description of the present disclosure has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the disclosure. The present embodiments were chosen and described in order to best explain the principles and practical application of the disclosure and to enable others skilled in the art to understand the disclosure in its various embodiments with various modifications as suited to the particular uses envisioned. [Explanation of symbols]

[0047] 90 Turbomachinery 100 Gas Turbine (GT) System 102 Compressor 104 Combustor 105 Combustion Zone 106 Fuel Nozzle Section 108 Turbine / Turbine Section 110 Compressor / Turbine Shaft / Rotor 112 Stationary vane / stator vane 114 Compressor blades / Turbine blades / Turbomachinery blades 114A Turbomachinery Blade 114B Turbomachinery Blade 115 Static Vane Section 116 rotor disc 120 Air 124 Static Casing 128 Vibration Damping System 130 base 132 Dovetail 134 Shank 136 Platform Platform 136A 136B Platform 137 Radial inner surface 138 Airfoil Body / Blade Airfoil 139 Radial outer surface 140 Concave pressure side (PS) outer wall / side wall 141 recess 142 Convex negative pressure side (SS) outer wall 144 leading edge 146 Trailing edge 148 Outer tip 150 spacer 154 Main Unit 156 Gas path facing surface 160 Dovetail 162 Vibration damping element coupler 164 Vibration Damping Elements 168 Axial Surface 169 Surface 170 U-shaped body 171 Lip 172 First Leg 174 Second Leg 176 Base part 178 Receptor 180 first bearing surface 182 second bearing surface 183 Radial outer surface / radial outer bearing surface 184 Radial inner surface 186 End 190 volts A rotor shaft S1 Compressor blade stage S2 Compressor blade stage S3 Compressor blade stage S4 Compressor blade stage WF Working fluid flow path

Claims

1. A vibration damping system (128) for at least one turbine blade (114) in a turbine (108), each turbine blade (114) having a platform (136, 136A, 136B) with a radially inner surface (137), said system (128) comprising: a spacer (150) axially adjacent the platform (136, 136A, 136B) of the at least one turbine blade (114) in the turbine (108), the spacer (150) including a body (154) having a gas path-facing surface (156) that forms a portion of an annulus for a working fluid flow path (WF); a vibration damping element coupler (162) on the body (154) of the spacer (150); a vibration damping element (164) configured to couple to said vibration damping element coupler (162); Equipped with the vibration-damping element (164) and the vibration-damping element coupler (162) are positioned to engage the vibration-damping element (164) with the radially inner surface (137) of the platform (136, 136A, 136B) of the at least one turbine blade (114) to damp vibrations of the at least one turbine blade (114) during operation of the turbine (108). System (128).

2. the at least one turbine blade (114) comprises a pair of circumferentially adjacent turbine blades (114, 114A, 114B), the radially inner surfaces (137) of the platforms (136, 136A, 136B) of the pair of circumferentially adjacent turbine blades (114, 114A, 114B) being adjacent to one another in the turbine (108); the vibration-damping element (164) and the vibration-damping element coupler (162) are arranged to engage the vibration-damping element (164) with the radially inner surface (137) of the platform (136, 136A, 136B) of each of the pair of circumferentially adjacent turbine blades (114, 114A, 114B) to damp vibrations of the pair of circumferentially adjacent turbine blades (114, 114A, 114B); 10. The system (128) of claim 1.

3. The system (128) of any preceding claim, wherein the vibration damping element coupler (162) extends from an axial surface (168) of the body (154) of the spacer (150).

4. The system (128) of claim 1, wherein the vibration damping element (164) includes a U-shaped body (170) configured to seat in the vibration damping element coupler (162).

5. 2. The system of claim 1, wherein the vibration damping element includes a first surface configured to engage the radially inner surface of the platform of the at least one turbine blade and damp vibrations of the at least one turbine blade.

6. 6. The system of claim 5, wherein the vibration damping element includes a second surface configured to axially engage the body of the spacer and to damp vibrations of the at least one turbine blade.

7. 7. The system of claim 6, wherein the second surface includes a radially outer surface and a spaced apart radially inner surface, each of the radially outer surface and the radially inner surface of the second surface configured to axially engage the body of the spacer and to damp vibrations of the at least one turbine blade.

8. The system (128) of claim 5, wherein the first surface (180) extends at an angle relative to an axis of a rotor (110) of the turbine (108).

9. 2. The system of claim 1, wherein in a non-operating state of the turbine, a first face is spaced apart from the radially inner surface of the platform.

10. The system (128) of claim 1, wherein the radially inner surface (137) of the platform (136, 136A, 136B) is positioned to reside in a recess (141) in the platform (136, 136A, 136B).

11. The system (128) of any preceding claim, wherein the vibration damping element coupler (162) includes at least one bolt (190) integral with the body (154) of the spacer (150).

12. A spacer (150) for positioning adjacent a stage of turbine blades (114) in a turbine (108), comprising: A main body (154); dovetails (132, 160) on said body (154); a gas path facing surface (156) on the body (154) and forming part of an annulus for a working fluid flow path (WF) adjacent the stage of turbine blades (114); a vibration-damping element coupler (162) on the body (154), the vibration-damping element (164) positioned to engage a radially inner surface (137) of a platform (136, 136A, 136B) of at least one turbine blade (114) and to damp vibrations of the at least one turbine blade (114) during operation of the turbine (108); A spacer (150) comprising:

13. the at least one turbine blade (114) comprises a pair of circumferentially adjacent turbine blades (114A, 114B); the vibration-damping element coupler (162) is positioned to engage the vibration-damping element (164) with the radially inner surface (137) of the platform (136, 136A, 136B) of each of the pair of circumferentially adjacent turbine blades (114A, 114B) to damp vibrations of the pair of circumferentially adjacent turbine blades (114A, 114B). The spacer (150) of claim 12.

14. The spacer (150) of claim 12, wherein the vibration damping element coupler (162) extends from an axial surface (168) of the body (154).

15. 13. The spacer (150) of claim 12, wherein the vibration damping element coupler (162) includes a surface (169) configured to receive a U-shaped vibration damping element (164) thereon.

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