Patent Description:
One concern in turbine operation is the tendency of the turbine blades or nozzles to undergo vibrational stress during operation. In many installations, turbines are operated under conditions of frequent acceleration and deceleration. During acceleration or deceleration of the turbine, the airfoils of the blades are, momentarily at least, subjected to vibrational stresses at certain frequencies and in many cases to vibrational stresses at secondary or tertiary frequencies. Nozzle airfoils experience similar vibrational stress. Variations in gas temperature, pressure, and/or density, for example, can excite vibrations throughout the rotor assembly, especially within the nozzle or blade airfoils. Gas exiting upstream of the turbine and/or compressor sections in a periodic, or "pulsating" manner can also excite undesirable vibrations. When an airfoil is subjected to vibrational stress, its amplitude of vibration can readily build up to a point which may alter operations. Wire mesh vibration damping members can be used to dampen vibration but have a tendency to move from their initial position during operation of the turbine nozzle or blade. <CIT> relates to a turbine damper that includes an elongated body sized to fit inside a turbine blade, the elongated body elongated along a radial direction of the turbine blade relative to a rotation axis of the turbine blade, and plural dampening masses coupled with the elongated body and disposed at different locations along the radial direction. <CIT> relates to a damping system for a turbomachine slip ring including a slip ring assembly.

All aspects, examples and features mentioned below can be combined in any technically possible way.

Two or more aspects described in this invention, including those described in this summary section, may be combined to form implementations not specifically described herein.

It is noted that the drawings of the invention are not necessarily to scale. The drawings are intended to depict only typical aspects of the invention and therefore should not be considered as limiting the scope of the invention.

As an initial matter, in order to clearly describe the subject matter of the current invention, it will become necessary to select certain terminology when referring to and describing relevant machine components within a turbine. To the extent possible, common industry terminology will be used and employed in a manner consistent with its accepted meaning. Unless otherwise stated, such terminology should be given a broad interpretation consistent with the context of the present application and the scope of the appended claims. Those of ordinary skill in the art will appreciate that often a particular component may be referred to using several different or overlapping terms. What may be described herein as being a single part may include and be referenced in another context as consisting of multiple components. Alternatively, what may be described herein as including multiple components may be referred to elsewhere as a single part.

In addition, several descriptive terms may be used regularly herein, and it should prove helpful to define these terms at the onset of this section. These terms and their definitions, unless stated otherwise, are as follows. As used herein, "downstream" and "upstream" are terms that indicate a direction relative to the flow of a fluid, such as the working fluid through the turbine engine or, for example, the flow of air through the combustor or coolant through one of the turbine's component systems. The term "downstream" corresponds to the direction of flow of the fluid, and the term "upstream" refers to the direction opposite to the flow (i.e., the direction from which the flow originates). The terms "forward" and "aft," without any further specificity, refer to directions, with "forward" referring to the front or compressor end of the engine, and "aft" referring to the rearward section of the turbomachine.

It is often required to describe parts that are disposed at differing radial positions with regard to a center axis. The term "radial" refers to movement or position perpendicular to an axis. For example, if a first component resides closer to the axis than a second component, it will be stated herein that the first component is "radially inward" or "inboard" of the second component. If, on the other hand, the first component resides further from the axis than the second component, it may be stated herein that the first component is "radially outward" or "outboard" of the second component. The term "axial" refers to movement or position parallel to an axis. Finally, the term "circumferential" refers to movement or position around an axis. It will be appreciated that such terms may be applied in relation to the center axis of the turbine.

It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. "Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur or that the subsequently describe component or element may or may not be present, and that the description includes instances where the event occurs or the component is present and instances where it does not or is not present.

Where an element or layer is referred to as being "on," "engaged to," "connected to" or "coupled to" another element or layer, it may be directly on, engaged to, connected to, or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly engaged to," "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers present.

Embodiments of the invention provide vibration damping systems for a turbine nozzle (vane) or turbine blade. The systems may include a body opening extending through a body of the turbine nozzle or blade between the tip end and the base end thereof, e.g., through the airfoil among potentially other parts of the nozzle or blade. A vibration damping element is disposed in the body opening and includes one or more elongated bodies each having a first, free end and a second end fixed relative to the base end or the tip end. At least one wire mesh member surrounds the elongated body(ies). A retention system is used to facilitate assembly, retain the wire mesh member(s) relative to a length of the elongated body, and/or retain the body opening in the turbine nozzle or blade.

The wire mesh member has a first outer dimension (ODM1) in an inoperative state and a second, larger outer dimension (ODM2) in an operative state. In an inoperative state, the wire mesh member slides freely in the body opening in the turbine nozzle or blade for assembly. In an operative state, the wire mesh member(s) frictionally engages with an inner surface of the body opening in the turbine nozzle or blade to damp vibration. The wire mesh member(s) is retained in the operative state by the retention system that includes a retention member on the elongated body. The retention member fixes the wire mesh member relative to a length of the elongated body in the body opening of the turbine nozzle or blade. Additionally, in the operative state, the wire mesh member frictionally engages with an inner surface of the body opening to damp vibration. Related methods of operation and assembly are also disclosed.

A vibration damping system may also include a vibration damping element including a plurality of contacting members including a plurality of damper pins. Each damper pin includes a body, and a wire mesh member surrounds the body of at least one of the plurality of damper pins. The wire mesh member has an outer dimension sized for frictionally engaging within a body opening in the turbine nozzle or blade to damp vibration. The plurality of contacting members may also include a spacing member that is devoid of a wire mesh member. The damper pins can have different sizes to accommodate contiguous body openings of different sizes in the nozzle or blade, reducing the weight of the vibration damping element. In this setting, the body opening can also be angled relative to a radial extent of the turbine nozzle or blade.

The vibration damping systems including the wire mesh member(s) reduce nozzle or blade vibration with a simple arrangement and do not add much extra mass to the nozzle or blade. Accordingly, the systems do not add additional centrifugal force to the nozzle base end or blade tip end or require a change in nozzle or blade configuration.

Referring to the drawings, <FIG> is a schematic view of an illustrative machine including a turbine(s) to which teachings of the invention can be applied. In <FIG>, a turbomachine <NUM> in the form of a combustion turbine or gas turbine (GT) system <NUM> (hereinafter, "GT system <NUM>") is shown. GT system <NUM> includes a compressor <NUM> and a combustor <NUM>. Combustor <NUM> includes a combustion region <NUM> and a fuel nozzle section <NUM>. GT system <NUM> also includes a turbine <NUM> and a common compressor/turbine shaft <NUM> (hereinafter referred to as "rotor <NUM>"). GT system <NUM> may be a 7HA. <NUM> engine, commercially available from General Electric Company, Greenville, S. The present invention is not limited to any one particular GT system and may be implemented in connection with other engines including, for example, the other HA, F, B, LM, GT, TM and E-class engine models of General Electric Company and engine models of other companies. More importantly, the teachings of the invention are not necessarily applicable to only a turbine in a GT system and may be applied to practically any type of industrial machine or other turbine, e.g., steam turbines, jet engines, compressors (as in <FIG>), turbofans, turbochargers, etc. Hence, reference to turbine <NUM> of GT system <NUM> is merely for descriptive purposes and is not limiting.

<FIG> shows a cross-sectional view of an illustrative portion of turbine <NUM>. In the example shown, turbine <NUM> includes four stages L0-L3 that may be used with GT system <NUM> in <FIG>. The four stages are referred to as L0, L1, L2, and L3. Stage L0 is the first stage and is the smallest (in a radial direction) of the four stages. Stage L1 is the second stage and is disposed adjacent the first stage LO in an axial direction. Stage L2 is the third stage and is disposed adjacent the second stage L1 in an axial direction. Stage L3 is the fourth, last stage and is the largest (in a radial direction). It is to be understood that four stages are shown as one example only, and each turbine may have more or less than four stages.

A plurality of stationary turbine vanes or nozzles <NUM> (hereafter "nozzle <NUM>," or "nozzles <NUM>") may cooperate with a plurality of rotating turbine blades <NUM> (hereafter "blade <NUM>," or "blades <NUM>") to form each stage L0-L3 of turbine <NUM> and to define a portion of a working fluid path through turbine <NUM>. Blades <NUM> in each stage are coupled to rotor <NUM> (<FIG>), e.g., by a respective rotor wheel <NUM> that couples them circumferentially to rotor <NUM> (<FIG>). That is, blades <NUM> are mechanically coupled in a circumferentially spaced manner to rotor <NUM>, e.g., by rotor wheels <NUM>. A static nozzle section <NUM> includes a plurality of stationary nozzles <NUM> circumferentially spaced around rotor <NUM> (<FIG>). It is recognized that blades <NUM> rotate with rotor <NUM> (<FIG>) and thus experience centrifugal force, while nozzles <NUM> are static.

With reference to <FIG> and <FIG>, in operation, air flows through compressor <NUM>, and pressurized air is supplied to combustor <NUM>. Specifically, the pressurized air is supplied to fuel nozzle section <NUM> that is integral to combustor <NUM>. Fuel nozzle section <NUM> is in flow communication with combustion region <NUM>. Fuel nozzle section <NUM> is also in flow communication with a fuel source (not shown in <FIG>) and channels fuel and air to combustion region <NUM>. Combustor <NUM> ignites and combusts fuel to produce combustion gases. Combustor <NUM> is in flow communication with turbine <NUM>, within which thermal energy from the combustion gas stream is converted to mechanical rotational energy by directing the combusted fuel (e.g., working fluid) into the working fluid path to turn blades <NUM>. Turbine <NUM> is rotatably coupled to and drives rotor <NUM>. Compressor <NUM> is rotatably coupled to rotor <NUM>. At least one end of rotor <NUM> may extend axially away from compressor <NUM> or turbine <NUM> and may be attached to a load or machinery (not shown), such as, but not limited to, a generator, a load compressor, and/or another turbine.

<FIG> and <FIG> show perspective views, respectively, of a (stationary) nozzle <NUM> or (rotating) blade <NUM>, of the type in which embodiments of a vibration damping system <NUM> and vibration damping element <NUM> of the present invention may be employed. As will be described herein, <FIG> show schematic cross-sectional views of a nozzle <NUM> or blade <NUM> including vibration damping system <NUM>.

Referring to <FIG> and <FIG>, each nozzle or blade <NUM>, <NUM> includes a body <NUM> having a base end <NUM>, a tip end <NUM>, and an airfoil <NUM> extending between base end <NUM> and tip end <NUM>. As shown in <FIG>, nozzle <NUM> includes an outer endwall <NUM> at base end <NUM> and an inner endwall <NUM> at tip end <NUM>. Outer endwall <NUM> couples to casing <NUM> (<FIG>). As shown in <FIG>, blade <NUM> includes a dovetail <NUM> at base end <NUM> by which blade <NUM> attaches to a rotor wheel <NUM> (<FIG>) of rotor <NUM> (<FIG>). Base end <NUM> of blade <NUM> may further include a shank <NUM> that extends between dovetail <NUM> and a platform <NUM>. Platform <NUM> is disposed at the junction of airfoil <NUM> and shank <NUM> and defines a portion of the inboard boundary of the working fluid path (<FIG>) through turbine <NUM>.

It will be appreciated that airfoil <NUM> in nozzle <NUM> and blade <NUM> is the active component of the nozzle <NUM> or blade <NUM> that intercepts the flow of working fluid and, in the case of blades <NUM>, induces rotor <NUM> (<FIG>) to rotate. It will be seen that airfoil <NUM> of nozzle <NUM> and blade <NUM> include a concave pressure side (PS) outer wall <NUM> and a circumferentially or laterally opposite convex suction side (SS) outer wall <NUM> extending axially between opposite leading and trailing edges <NUM>, <NUM>, respectively. Sidewalls <NUM> and <NUM> also extend in the radial direction from base end <NUM> (i.e., outer endwall <NUM> for nozzle <NUM> and platform <NUM> for blade <NUM>) to tip end <NUM> (i.e., inner endwall <NUM> for nozzle <NUM> and a tip end <NUM> for blade <NUM>). Note, in the example shown, blade <NUM> does not include a tip shroud; however, teachings of the invention are equally applicable to a blade including a tip shroud at tip end <NUM>.

As noted, during operation of a turbine, nozzles <NUM> or blades <NUM> may be excited into vibration by a number of different forcing functions. Variations in, for example, working fluid temperature, pressure, and/or density can excite vibrations throughout the rotor assembly, especially within the airfoils and/or tips of the blades or nozzles. Gas exiting upstream of the turbine and/or compressor sections in a periodic, or "pulsating," manner can also excite undesirable vibrations. The present invention aims to reduce the vibration of a stationary turbine nozzle <NUM> or rotating turbine blade <NUM> without significant change of nozzle or blade design.

Referring to <FIG>, schematic cross-sectional views of nozzle <NUM> or blade <NUM> including vibration damping system <NUM> are illustrated. (Nozzle <NUM> in the schematic view of <FIG> is shown flipped vertically compared to that shown in <FIG> and without the inner endwall <NUM>, for ease of description. ) Vibration damping system <NUM> for turbine nozzle <NUM> or blade <NUM> may include a body opening <NUM> extending through body <NUM> between tip end <NUM> and base end <NUM> thereof and through airfoil <NUM>. Body opening <NUM> may extend part of the distance between base end <NUM> and tip end <NUM>, or it may extend through one or more of base end <NUM> or tip end <NUM>. Body opening <NUM> may be defined in any part of any structure of body <NUM>. For example, where body <NUM> includes an internal partition wall (not shown), for example, for defining a cooling circuit therein, body opening <NUM> may be defined as an internal cavity in the partition wall in body <NUM>. Body opening <NUM> generally extends radially in body <NUM>. However, as will be described herein, some angling, and perhaps curving, of body opening <NUM> relative to a radial extent of body <NUM> is possible.

Vibration damping system <NUM> for nozzles <NUM> or blades <NUM> may also include a vibration damping element <NUM> disposed in body opening <NUM>. Vibration damping element <NUM> may include one or more elongated bodies <NUM> each including a first, free end <NUM> and a second end <NUM> fixed relative to base end <NUM> or tip end <NUM>. Body opening <NUM> has a dimension greater than a corresponding outer dimension of elongated body(ies) <NUM>, allowing elongated body(ies) <NUM> a limited movement range within body opening <NUM> to dampen vibrations through deflection thereof within body opening <NUM>. Elongated body(ies) <NUM> may damp vibration by deflection thereof in body opening <NUM> as they extend radially between tip end <NUM> and base end <NUM> of body <NUM> of turbine nozzle <NUM> or blade <NUM>.

Elongated body(ies) <NUM> may have any length desired to provide a desired deflection and vibration damping within nozzle <NUM> or blade <NUM> and, as will be described, to engage with any number of wire mesh members <NUM>. Elongated body(ies) <NUM> may have any desired cross-sectional shape to provide a desired vibration damping within nozzle <NUM> or blade <NUM>. For example, elongated body(ies) <NUM> may have a circular or oval cross-sectional shape, i.e., they are cylindrical or rod shaped (see e.g., <FIG>). However, other cross-sectional shapes are also possible. Elongated body(ies) <NUM> may be made of any material having the desired vibration resistance required for a particular application, e.g., a metal or metal alloy. In some embodiments, elongated body(ies) <NUM> may need to be very rigid or stiff, which could require alternative stiffer materials than metal or metal alloy such as, but not limited to, ceramic matrix composites (CMC).

Vibration damping element <NUM> of vibration damping system <NUM> also includes at least one wire mesh member <NUM> surrounding each elongated body <NUM>. As will be further described, wire mesh member(s) <NUM> frictionally engages with an inner surface <NUM> of body opening <NUM> to damp vibration. <FIG> shows a perspective view, and <FIG> shows an enlarged partial view of an illustrative wire mesh member <NUM>. Wire mesh member <NUM> includes any now known or later developed wire mesh damping material suitable for restricting movement of elongated body(ies) <NUM>. As will be described herein, wire mesh member(s) <NUM> may also surround damper pins <NUM> (<FIG>) in other embodiments of the invention. Wire mesh member(s) <NUM> may also be coated in various coating materials to alter frictional properties thereof. Wire mesh member <NUM> may be referred to as 'metal rubber. " As shown in <FIG>, wire mesh member(s) <NUM> may include a knitted wire-mesh material <NUM>.

As will be described in greater detail herein, wire mesh member(s) <NUM> surround elongated body(ies) <NUM> or a damper pin <NUM> (<FIG>). More particularly, a mesh opening <NUM> in wire mesh member(s) <NUM> has a shape and dimensions to surround one elongated body <NUM>, numerous elongated bodies 168A-B (see e.g., <FIG>), or a body <NUM> of a damper pin <NUM> (<FIG>). In the examples shown in <FIG>, mesh opening <NUM> is circular and has an inner dimension (IDM), e.g., inner diameter, sized to surround an elongated body <NUM> or body <NUM> of damper pin <NUM> (<FIG>). Other shapes are also possible.

As will be further described, an outer shape of wire mesh member(s) <NUM> is shaped and dimensioned to fit snugly within body opening <NUM> in an operative state. For example, wire mesh member(s) <NUM> may have an outer dimension (ODM), e.g., outer diameter, configured to have an interference fit within body opening <NUM> of turbine nozzle <NUM> or blade <NUM> in an operative state. In the example shown, wire mesh member(s) <NUM> and body opening <NUM> have circular cross-sections; however, other shapes are also possible, e.g., polygonal, oval, etc..

Wire mesh member(s) <NUM> may be stiff, but still compliant in the radial and axial direction thereof. In this manner, wire mesh member(s) <NUM> provides damping of vibration by frictional engagement thereof with inner surface <NUM> of body opening <NUM> in an operative state. The length L of wire mesh member(s) <NUM> can be customized for the particular application. Any number of wire mesh member(s) <NUM> can be used, i.e., one or more. Where a plurality of wire mesh members <NUM> are used, they may be spaced along elongated body(ies) <NUM>. Each wire mesh member <NUM> may thus engage with a different portion of inner surface <NUM> of body opening <NUM> and a different portion of a respective elongated body <NUM>. In certain embodiments, two or more wire mesh members <NUM> may axially engage with one another to collectively form a longer, stacked wire mesh member.

Wire mesh member(s) <NUM> are retained with retention member(s) <NUM> relative to a length of elongated body <NUM> or damper pin <NUM> (<FIG>). While wire mesh member(s) <NUM> are retained in this manner, it will be recognized that the wire mesh member(s) <NUM> move a limited amount as part of their function. In embodiments where a single wire mesh member <NUM> with a single retention member <NUM> is illustrated (e.g., <FIG> and <FIG>), it will be recognized that the wire mesh member <NUM> may include two or more spaced wire mesh members <NUM> each with their own retention member <NUM>.

Vibration damping system <NUM> using a vibration damping element <NUM> with elongated body <NUM> can take a number of forms. <FIG> and <FIG> show embodiments in which a single elongated body <NUM> is used, and <FIG> shows an embodiment in which more than one elongated body <NUM> is used.

<FIG> shows an embodiment in which second end <NUM> of elongated body <NUM> is fixed relative to tip end <NUM> of body <NUM>, and first, free end <NUM> extends towards base end <NUM>. Second end <NUM> may be fixed within outer endwall <NUM> (<FIG>) of nozzle <NUM> or within tip end <NUM> (<FIG>) of blade <NUM>. While the single elongated body <NUM> is shown having free end <NUM> thereof extending into base end <NUM>, i.e., into inner endwall <NUM> (<FIG>) of nozzle <NUM> or into shank <NUM> (<FIG>) of blade <NUM>, that is not necessary in all cases. Second end <NUM> may be fixed in any now known or later developed manner. In one example, where used in turbine blade <NUM>, second end <NUM> can be fixed by radial loading during operation of turbine <NUM> (<FIG>), i.e., by centrifugal force. In another example, second end <NUM> may be physically fixed, e.g., by fastening using couplers, fasteners, and/or welding. For example, an elongated body 168A (shown in <FIG>) includes second end <NUM> that may be physically fixed in tip end <NUM> by threaded fasteners (not shown).

Wire mesh member(s) <NUM> may be retained in position or limited in movement using a number of techniques. In accordance with embodiments of the invention, a retention system <NUM> includes a retention member <NUM> on elongated body <NUM> to fix wire mesh member(s) <NUM> relative to a length of elongated body <NUM> in an operative state in body opening <NUM> of turbine nozzle <NUM> or blade <NUM>. In one example shown in <FIG>, retention member <NUM> extends from elongated body <NUM> to engage an end <NUM> (<FIG>) of wire mesh member(s) <NUM> to allow limited sliding movement (and limited compression) of at least one wire mesh member 180A relative to a length of elongated body <NUM> (i.e., longitudinally along elongated body <NUM>) and radially relative to an axis of turbine <NUM> (<FIG>). In some cases, retention member(s) <NUM> also prevents wire mesh member(s) <NUM> from moving off elongated body <NUM>. As illustrated in <FIG>, where other wire mesh members 180B, 180C are optionally provided, retention members <NUM> may not be necessary. In another non-claimed example, as shown in <FIG>, for turbine blades <NUM>, tip end <NUM> may retain wire mesh member 180C against centrifugal force of the rotating blade. Alternative forms of a retention member <NUM> will be described herein.

Body opening <NUM> may terminate in base end <NUM>, or as shown in <FIG>, it may extend through base end <NUM>. The latter scenario may assist in assembly of vibration damping system <NUM> in nozzle <NUM> or blade <NUM> and may allow retrofitting of the system into an existing nozzle or blade. Where body opening <NUM> extends through base end <NUM>, as shown in <FIG>, a closure <NUM> for body opening <NUM> in base end <NUM> may be provided. Closure <NUM> may also be employed to retain and/or direct elongated body <NUM> into an operational state within body opening <NUM>.

In the <FIG> embodiment, vibration damping system <NUM> operates with second end <NUM> of elongated body <NUM> moving with tip end <NUM>, i.e., with airfoil <NUM>, driving relative motion with base end <NUM> of nozzle <NUM> or blade <NUM>. Here, vibration damping system <NUM> allows vibration damping through deflection of elongated body <NUM> and frictional engagement of wire mesh member(s) <NUM> with inner surface <NUM> of body opening <NUM>. For turbine blades <NUM>, this arrangement may also advantageously present lower radial force (G-load) on wire mesh member(s) <NUM> because of the presence of wire mesh member 180A in base end <NUM> rather than tip end <NUM>. Wire mesh member(s) 180A in base end <NUM> may result in less compression of member(s) <NUM> in turbine blade <NUM>, thus extending their useful life for blades <NUM>. In nozzles or blades, base end <NUM> may also provide lower temperatures, which could be beneficial for longevity of the system.

Referring to <FIG>, in another embodiment, second end <NUM> of elongated body <NUM> is fixed relative to base end <NUM> of body <NUM> of turbine nozzle <NUM> or blade <NUM>, and first, free end <NUM> extends towards tip end <NUM>. Any number of wire mesh member(s) <NUM> (one or a plurality) are retained from sliding movement along the elongated body <NUM> using any now known or later developed retention member(s) <NUM>. In one example, retention member <NUM> may be positioned on elongated body <NUM> (i.e., radial outer end thereof) to prevent wire mesh member(s) <NUM> from moving relative to a length of elongated body <NUM>, e.g., because of centrifugal force.

For turbine blades <NUM>, vibration damping system <NUM> may also optionally include a compression member <NUM> movable along elongated body <NUM> to compress wire mesh member(s) <NUM> against retention member <NUM> during operation of turbine nozzle <NUM> or blade <NUM>, i.e., beyond the compression provided by centrifugal force of the rotating blades <NUM>. The compression adds force to the frictional engagement of wire mesh member(s) <NUM> with inner surface <NUM> of body opening <NUM> to provide additional vibration damping. Wire mesh member(s) <NUM> is/are positioned between retention member <NUM> and compression member <NUM>. Compression member <NUM> may include any form of movable weight that can compress wire mesh member(s) <NUM>, e.g., as caused by the application of centrifugal force on blade <NUM> during use.

Body opening <NUM> may terminate in base end <NUM> (as shown in <FIG>), or it may extend through base end <NUM> (as shown in <FIG>). In the latter scenario, a fixing member <NUM> may be provided to fixedly couple second end <NUM> of elongated body <NUM> relative to base end <NUM>. Where body opening <NUM> extends through base end <NUM>, fixing member <NUM> may also be employed to retain elongated body <NUM> in an operational state within body opening <NUM>. Fixing member <NUM> may include any now known or later developed structure to fixedly couple elongated body <NUM> relative to base end <NUM> in body opening <NUM>, e.g., a plate with a fastener or weld for elongated body <NUM>. In the <FIG> embodiment, elongated body <NUM> is not vibrating extensively with airfoil <NUM>, so the majority of relative motion exists between wire mesh member(s) <NUM> and inner surface <NUM> of body opening <NUM>. The compression of wire mesh member(s) <NUM> increases frictional engagement with inner surface <NUM> of body opening <NUM> to increase vibration damping.

Referring to <FIG>, in another non-claimed embodiment, more than one elongated body <NUM> can be used. Here, elongated bodies <NUM> include at least one first elongated body 168A having second end 172A thereof fixed relative to tip end <NUM> of body <NUM>, and first, free end 170A thereof extending towards base end <NUM>. Elongated bodies <NUM> also include at least one second elongated body 168B having second end 172B thereof fixed relative to base end <NUM> of body <NUM>, and first, free end 170B thereof extending towards tip end <NUM>. Any number of each elongated bodies 168A, 168B may be employed.

Wire mesh member(s) <NUM> surround both types of elongated bodies 168A, 168B to force each elongated body 168A, 168B into contact with at least one other elongated body 168A, 168B during operation of turbine nozzle <NUM> or blade <NUM>. In this manner, each elongated body 168A, 168B is in contact with at least one other first elongated body 168A fixed to tip end <NUM> and/or at least one other second elongated body 168B fixed to base end <NUM>.

<FIG> show cross-sectional views along view line A-A in <FIG> of various embodiments. <FIG> shows a cross-sectional view of an embodiment including one first elongated body 168A, and one second elongated body 168B. <FIG> shows a cross-sectional view including a plurality of (e.g., two) first elongated bodies 168A, and a plurality of (e.g., two) second elongated bodies 168B. Any number of each type of elongated body 168A, 168B may be used so long as they can be surrounded by wire mesh member(s) <NUM> to allow limited movement within body opening <NUM>, e.g., circumferentially (into and out of page) and radially (up and down page).

In the <FIG> embodiment, a retention member <NUM> may be provided to retain wire mesh member(s) <NUM> relative to a length of first and second elongated bodies 168A, 168B. In one example, retention member <NUM> may be positioned on one or more of elongated bodies 168A and/or 168B, as in <FIG>, to prevent wire mesh member(s) <NUM> from moving relative to a length of elongated bodies <NUM>, e.g., because of centrifugal or vibrational forces of blades <NUM> or vibrational forces of nozzle <NUM>. Alternatively, as shown in <FIG>, retention member <NUM> may be provided by a closed end <NUM> of body opening <NUM> at tip end <NUM> in body <NUM>. (Note, this retention member arrangement can also be used as an alternative for the <FIG> embodiment. ) In <FIG>, fixed end 172A of elongated body(ies) 168A may be fixed by being threaded or otherwise fastened into closed end <NUM> of body opening <NUM>. Although not shown, fixed end 172B of elongated body(ies) 168B may be similarly fixed in base end <NUM>.

Vibration damping system <NUM> may also optionally include, for blades <NUM>, a compression member <NUM> movable along one or more of first elongated body(ies) 168A and second elongated body(ies) 168B to compress wire mesh member(s) <NUM> against retention member <NUM> during operation of turbine blade <NUM>. Wire mesh member(s) <NUM> is/are positioned between retention member <NUM> and compression member <NUM>. Compression member <NUM> may include any form of movable weight that can compress wire mesh member(s) <NUM>, e.g., as occurs with the application of centrifugal force on blade <NUM> during use.

In the <FIG> embodiments, while some vibration damping occurs by way of elongated body(ies) 168A, 168B deflecting and some vibration damping occurs by wire mesh member(s) <NUM> frictionally engaging inner surface <NUM> of body opening <NUM>, they are not the primary damping mechanism. Rather, the primary damping mechanism is elongated bodies 168A, 168B rubbing together. The force by which elongated bodies 168A, 168B engage can be controlled, in part, by the compression of wire mesh member(s) <NUM> by centrifugal force and/or compression member <NUM>.

A method of damping vibration in turbine nozzle <NUM> or blade <NUM> according to various embodiments may include, during operation of turbine nozzle <NUM> or blade <NUM>, providing various levels of different vibration damping. For example, a method may damp vibration by deflection of elongated body(ies) <NUM> disposed radially in body opening <NUM> and extending between tip end <NUM> and base end <NUM> of body <NUM> of turbine nozzle <NUM> or blade <NUM>. As noted, each elongated body(ies) <NUM> may include first, free end <NUM> and second end <NUM> fixed relative to base end <NUM> or tip end <NUM> of body <NUM>. The method may also damp vibration by frictional engagement of wire mesh member(s) <NUM> surrounding elongated body(ies) <NUM> with inner surface <NUM> of body opening <NUM>. The knitted nature of wire mesh member(s) <NUM> may create friction, thus dissipating the input energy from the vibration. The frictional forces restrict motion of elongated body(ies) <NUM>, thus reducing displacement. For rotating blades <NUM>, damping of vibration by frictional engagement may be increased, where desired, by compressing wire mesh member(s) <NUM> to increase a force of frictional engagement of wire mesh member(s) <NUM> with inner surface <NUM> of body opening <NUM>.

In certain embodiments, like those shown in <FIG>, which include multiple types of elongated bodies 168A, 168B, the method may also include damping vibration by frictionally engaging each of elongated bodies 168A, 168B with one or more other elongated bodies 168A, 168B. In the <FIG> embodiment, for blades <NUM>, compressing wire mesh member(s) <NUM> may result in increasing the damping of vibration by increasing a force of the frictional engagement of wire mesh member(s) <NUM> with inner surface <NUM> of body opening <NUM>, and increasing the damping of vibration by increasing a force of the frictional engagement of each of elongated bodies 168A, 168B with one or more other elongated bodies 168A, 168B.

Assembly of vibration damping system <NUM> and retention of wire mesh member(s) <NUM> in body opening <NUM> relative to a length of elongated body <NUM> of vibration damping element(s) <NUM> can be carried out in a number of ways. As noted, wire mesh member(s) <NUM> are sized to achieve an interference fit with inner surface <NUM> of body opening <NUM> in an operative state to provide vibration damping. In one non-limiting example, wire mesh member <NUM> may have an outer dimension (ODM), e.g., outer diameter, in an operative state of approximately <NUM> millimeters (mm) and body opening <NUM> may have an inner dimension (IDB), e.g., inner diameter, of approximately <NUM>. In one approach, wire mesh member(s) <NUM> are positioned on elongated body(ies) <NUM> and forced into body opening <NUM>, perhaps with the aid of a lubricant such as graphite powder.

In some cases, the forceful insertion can displace wire mesh member(s) <NUM> or cause damage to the members. Hence, it may be difficult to position each wire mesh member <NUM> in body opening <NUM>, and it may be difficult to position each wire mesh member <NUM> in the desired longitudinal position along elongated body(ies) <NUM> and achieve the interference fit. At the same time, over-compression of wire mesh member(s) <NUM> can occur if one or more wire mesh member(s) <NUM> are allowed to slide or compress too much relative to a length of elongated body(ies) <NUM>. Over-compression can also occur where a particular wire mesh member <NUM> is too long, resulting in one end <NUM> (<FIG>) thereof being compressed significantly more than an opposing end <NUM> (<FIG>) thereof.

Wire mesh member(s) <NUM> may be assembled and retained in position or limited in movement using a variety of techniques. For example, as described relative to <FIG> and <FIG>, a retention member <NUM> may be positioned on elongated body <NUM>, e.g., as a wider part thereof, to allow limited sliding movement (and limited compression) of at least one wire mesh member <NUM> relative to a length of elongated body <NUM>, i.e., longitudinally along elongated body <NUM> and radially relative to an axis of turbine <NUM> (<FIG>). For assembly, wire mesh member(s) <NUM> may be positioned on elongated body <NUM> and collectively inserted with elongated body <NUM> into body opening <NUM>. Alternatively, elongated body <NUM> may be fixed in body opening <NUM>, and wire mesh member <NUM> can be forced onto, and perhaps along, elongated body <NUM> until it meets retention member <NUM>. Where an end of body opening <NUM> acts as a retention member <NUM>, as in <FIG>, wire mesh member(s) <NUM> may be positioned in body opening <NUM>, and elongated body(ies) <NUM> inserted into the wire mesh member(s) <NUM>. In any event, in the examples shown in <FIG>, retention member <NUM> of retention system <NUM> is external of wire mesh member(s) <NUM> and abuts an end <NUM> (<FIG>) of wire mesh member(s) <NUM> to position it/them in an operative state in body opening <NUM>.

Referring to <FIG>, additional embodiments of retention system <NUM> with retention member(s) <NUM> for vibration damping elements <NUM> will now be described. In these embodiments, as in previous embodiments, retention member <NUM> is on elongated body <NUM> to fix wire mesh member <NUM> in body opening <NUM> of turbine nozzle <NUM> or blade <NUM> in an operative state. However, retention member(s) <NUM> in these embodiments engage within mesh opening <NUM> (<FIG>) to better secure wire mesh member(s) <NUM> in the operative state. While these embodiments will be described as mutually exclusive of retention member(s) <NUM> in <FIG>, it will be recognized that any of the various embodiments may be used together.

The <FIG> embodiments enable a method of assembling vibration damping system <NUM> in turbine nozzle <NUM> or blade <NUM> that includes positioning wire mesh member(s) <NUM> in body opening <NUM> prior to positioning elongated body <NUM> therein. As shown in <FIG>, wire mesh member(s) <NUM> have mesh opening <NUM> therein having inner dimension (IDM) and (first) outer dimension (ODM). As shown in <FIG>, outer dimension ODM of wire mesh member(s) <NUM> may be sized to be less than an inner dimension (IDB) of body opening <NUM>. Hence, wire mesh member(s) <NUM> slide freely and easily in body opening <NUM> in turbine nozzle <NUM> or blade <NUM> in the inoperative state, i.e., in which they are not fixed by a retention member <NUM>. Any number of wire mesh member(s) <NUM> can be positioned in body opening <NUM> in this manner. The method may then include positioning elongated body <NUM> within respective mesh opening(s) <NUM> of wire mesh member(s) <NUM> within body opening <NUM>.

As shown for example in <FIG>, during the assembly process, retention member(s) <NUM> on elongated body <NUM> are used to fix wire mesh member(s) <NUM> relative to a length of elongated body <NUM> in an operative state in body opening <NUM> of turbine nozzle <NUM> or blade <NUM> by creating a (second) larger outer dimension (ODM2) in wire mesh member(s) <NUM> that frictionally engages with inner surface <NUM> of body opening <NUM> in turbine nozzle <NUM> or blade <NUM>. The method may also include, as shown in <FIG> and <FIG>, fixing elongated body <NUM> relative to one of base end <NUM> and tip end <NUM> such that second end <NUM> of elongated body <NUM> is fixed relative to base end <NUM> or tip end <NUM> and first end <NUM> remains free (i.e., unfixed).

<FIG> shows a perspective view of elongated body <NUM> including a retention system <NUM>; <FIG> shows an exploded, schematic cross-sectional view of retention system <NUM> in <FIG> before assembly; and <FIG> shows a schematic cross-sectional view of retention system <NUM> of <FIG> after assembly and positioning in body opening <NUM>. In this embodiment and as shown in <FIG> and <FIG>, each retention member <NUM> includes a protrusion <NUM> on a first portion <NUM> of an outer surface <NUM> of elongated body <NUM>. Elongated body <NUM> also includes a second portion <NUM> on outer surface <NUM> where protrusion <NUM> is not present. As shown in <FIG>, wire mesh member(s) <NUM> have a first outer dimension (ODM1) and mesh opening <NUM> has an inner dimension (IDM) in an inoperative state, i.e., apart from an elongated body <NUM> (see also <FIG>). In the inoperative state shown in <FIG>, inner dimension (IDM) of mesh opening <NUM> in a first section of wire mesh member <NUM> may be larger than outer dimension (ODB) of second portion <NUM> of elongated body <NUM> to allow wire mesh member <NUM> to slide freely over second portion <NUM> of elongated body <NUM>. Additionally, first outer dimension (ODM1) of wire mesh member <NUM> may be smaller than inner dimension (IDMB) of body opening <NUM> so it can slide freely in body opening <NUM> of turbine nozzle <NUM> or blade <NUM>. In this manner, during assembly, wire mesh member(s) <NUM> can be positioned in body opening <NUM>, and elongated body <NUM> engaged into wire mesh member <NUM> in body opening <NUM>.

As shown in <FIG>, as insertion of elongated body <NUM> into wire mesh member(s) <NUM> occurs, protrusion(s) <NUM> expands wire mesh member(s) <NUM> in the first section thereof to create second, larger outer dimension (ODM2) therein. To attain an operative state, positioning of elongated body <NUM> may include engaging protrusion(s) <NUM> within inner dimension (IDM) of mesh opening <NUM> in the first section of wire mesh member(s) <NUM> to create second, larger outer dimension (ODM2) on wire mesh member(s) <NUM>. That is, protrusion(s) <NUM> engage within inner dimension (IDM) (<FIG>) of mesh opening <NUM> in the first section of wire mesh member(s) <NUM> to create second, larger outer dimension (ODM2) on wire mesh member(s) <NUM>. The first section of wire mesh member <NUM> is compressed and fixed relative to a length of elongated body <NUM> where protrusion(s) <NUM> exist, i.e., in an operative state in an interference fit.

Where protrusion <NUM> does not exist, a second section of wire mesh member <NUM> different than the first section is not compressed, and wire mesh member <NUM> may slide freely and stretch relative to second portion <NUM> of elongated body <NUM>. That is, wire mesh member <NUM> is allowed to stretch (see double-headed arrow A in <FIG>) over second portion <NUM>. Hence, wire mesh member(s) <NUM> surrounds elongated body <NUM> and has first outer dimension ODM1 in an inoperative state. Where protrusion(s) <NUM> exist, wire mesh member(s) <NUM> has second, larger outer dimension ODM2 in an operative state.

As shown in <FIG>, in the operative state, wire mesh member <NUM> frictionally engages with inner surface <NUM> of body opening <NUM> in turbine nozzle <NUM> or blade <NUM> to damp vibration, i.e., where protrusion <NUM> exists. Protrusion <NUM> may have any shape necessary to allow sliding insertion into, and outward compression of, wire mesh member(s) <NUM> during assembly. Protrusion(s) <NUM> may extend any extent around and/or along elongated body <NUM> to create the desired second outer dimension (ODM2). In the exemplary embodiment, protrusion(s) <NUM> may extend symmetrically around the full circumference of elongated body <NUM>, although such symmetry is not required. Any number of protrusion(s) <NUM> may be provide on elongated body <NUM>, e.g., one for each wire mesh member <NUM>. The <FIG> embodiments can also use a retention member <NUM> like that shown in <FIG> and <FIG>.

It will be recognized that the <FIG> embodiment may also be used in a method in which wire mesh member(s) <NUM> are positioned on elongated body <NUM> before insertion into body opening <NUM>. That is, each wire mesh member <NUM> may be positioned over a respective protrusion <NUM> on elongated body <NUM> to create second larger outer dimension (ODM2), and then elongated body <NUM> and wire mesh member(s) <NUM> can be inserted into body opening <NUM> together, perhaps with the aid of a lubricant. The <FIG> embodiment can also be used in circumstances in which elongated body <NUM> is fixed in body opening <NUM> first, and then wire mesh member(s) <NUM> are inserted over elongated body <NUM>. This latter approach would require the section of elongated body <NUM> that includes protrusions <NUM> to be accessible through tip end <NUM> or base end <NUM> of turbine nozzle <NUM> or blade <NUM>.

<FIG> shows an exploded side view, and <FIG> shows an assembled side view of an elongated body <NUM> including a retention system <NUM> and retention member <NUM>, according to another embodiment of the invention. In this embodiment, each retention member <NUM> includes a threaded section <NUM> on a first portion <NUM> of an outer surface <NUM> of elongated body <NUM>. Elongated member <NUM> may also optionally include a non-threaded section <NUM> on a second portion <NUM> on outer surface <NUM> of elongated body <NUM>. Where thread-free, second portion <NUM> is provided, inner dimension (IDM) of mesh opening <NUM> of wire mesh member <NUM> slides freely relative to second portion <NUM> of elongated body <NUM>. Any number of threaded sections <NUM> can be provided to thread into a respective number of wire mesh members <NUM>. Threaded section(s) <NUM> have an outer dimension (ODT) larger than inner dimension (IDM) (<FIG>) of mesh opening <NUM> in wire mesh member <NUM> to create second, larger outer dimension (ODM2) (<FIG>) on wire mesh member <NUM> in the operative state (<FIG>), i.e., when threaded into wire mesh member(s) <NUM>. For this embodiment, after positioning wire mesh member(s) <NUM> in body opening <NUM>, the positioning of elongated body <NUM> may include threading first portion(s) <NUM> into mesh opening <NUM> to create second, larger outer dimension (ODM2) on wire mesh member(s) <NUM>. Threaded portion(s) <NUM> can also find advantage in disassembling vibration damping element <NUM> by unthreading wire mesh member(s) <NUM>.

Threaded section(s) <NUM> may have any threading format necessary to allow threaded insertion into, and outward compression of, wire mesh member(s) <NUM> during assembly. Threaded section(s) <NUM> may extend any extent around and/or along elongated body <NUM> to create the desired second outer dimension (ODM2). Any number of threaded section(s) <NUM> may be provided on elongated body <NUM>, e.g., one for each wire mesh member <NUM>. Threaded section <NUM> may also alternatively extend an entire length of elongated body <NUM>. The <FIG> embodiments can also use a retention member <NUM> like that shown in <FIG> and <FIG>.

It will be recognized that the <FIG> embodiment may also be used in a method in which wire mesh member(s) <NUM> are positioned on elongated body <NUM> before insertion into body opening <NUM>. That is, wire mesh member(s) <NUM> may be positioned over threaded sections <NUM> on elongated body <NUM> to create second larger outer dimension (ODM2), and then elongated body <NUM> and wire mesh member(s) <NUM> can be inserted into body opening <NUM> together, perhaps with the aid of a lubricant.

Vibration damping element <NUM> employing a rigid, elongated body <NUM> is not always desirable. For example, as noted, assembly can be challenging, especially where more than a couple of wire mesh members <NUM> are desired. As noted, wire mesh member(s) <NUM> are arranged in an interference fit with inner surface <NUM> of body opening <NUM> to provide vibration damping. Use of a rigid, elongated body <NUM> can present challenges in obtaining fixation of more than a couple wire mesh members <NUM>. To address this challenge, embodiments of the disclosure may also include a vibration damping element <NUM> that includes a plurality of contacting members <NUM> that contact one another in a stacked or columnar manner within body opening <NUM>. Contacting members <NUM> may include a plurality of damper pins <NUM>, at least one of which may include a wire mesh member <NUM> thereon. In this manner, assembly may include positioning any number of damper pins <NUM> with wire mesh members <NUM> thereon sequentially into body opening <NUM> to create vibration damping element <NUM>.

<FIG> shows a schematic cross-sectional view of turbine nozzle <NUM> or blade <NUM> having a non-claimed vibration damping system <NUM> for a turbine nozzle <NUM> or blade <NUM>. In this setting, vibration damping element <NUM> includes a plurality of contacting members <NUM> including a plurality of damper pins <NUM>. Any number of damper pins <NUM> may be used to create vibration damping element <NUM>. For example, in <FIG>, ten (<NUM>) sequential damper pins <NUM> are used.

<FIG> shows a cross-sectional view of a non-claimed damper pin <NUM> in a body opening <NUM> in a turbine nozzle <NUM> or blade <NUM>. Each damper pin <NUM> includes a body <NUM>. A wire mesh member <NUM>, as described herein, surrounds body <NUM> of at least one of plurality of damper pins <NUM>. Wire mesh member <NUM> may have an outer dimension (ODM2) sized to frictionally engage within body opening <NUM> having inner dimension (IDB) in turbine nozzle <NUM> or blade <NUM> to damp vibration. As shown in <FIG>, damper pins <NUM> are arranged in a stacked or columnar fashion (somewhat similar to a spinal column) such that friction between damper pins <NUM> dampens vibration. Wire mesh members <NUM> allow damper pins <NUM> to be inserted in a centered fashion and forces pins <NUM> to move independently to dampen vibration by friction between adjacent damper pins <NUM>. Friction between wire mesh members <NUM> and inner surface <NUM> of body opening <NUM> also dampens vibration. Damper pins <NUM> may be inserted in body opening <NUM> with force, perhaps with the aid of a lubricant, e.g., a graphite lubricant.

<FIG> shows a cross-sectional view of another non-claimed optional embodiment. In this embodiment, plurality of contacting members <NUM> may further include a spacing member <NUM> between a pair of damper pins <NUM>. Spacing member(s) <NUM> have a body <NUM>. Any number of spacing members <NUM> may be employed to lengthen vibration damping element <NUM>. Spacing member(s) <NUM> are devoid of wire mesh member <NUM>, i.e., there is no wire mesh member on body <NUM> of spacing member <NUM>. Body <NUM> of spacing member(s) <NUM> can have any desired outer dimension (ODS) smaller than inner dimension (IDB) (<FIG>) of body opening <NUM>. Spacing member(s) <NUM> can have any desired length.

As shown in <FIG> and <FIG>, each spacing member <NUM> and each damper pin <NUM> are configured to slidingly engage along mating end surfaces <NUM>, <NUM> of body <NUM> of damper pins <NUM> or body <NUM> of spacing member <NUM> to form frictional joints therebetween. That is, each spacing member <NUM> and each damper pin <NUM> have a body having a first mating end surface <NUM> and a second mating end surface <NUM> complementary to first mating end surface <NUM>. The mating end surfaces <NUM>, <NUM> of spacing member <NUM> each slidingly engage with a complementary mating end surface <NUM>, <NUM> of the pair adjacent damper pins <NUM> to form a pair of frictional joints. In the example shown in <FIG> and <FIG>, mating end surfaces <NUM>, <NUM> have a concave end surface <NUM> and a convex end surface <NUM> complementary to concave end surface <NUM>. That is, concave end surface <NUM> and convex end surface <NUM> each have a radius of curvature that allows them to slidingly engage to form a pair of frictional joints. As shown in <FIG>, concave end surface <NUM> and convex end surface <NUM> of damper pins <NUM> each may slidingly engage with a complementary convex end surface <NUM> and concave end surface <NUM> of adjacent damper pins <NUM> to form a frictional joint. As shown in <FIG>, where spacing member(s) <NUM> are used, concave end surface <NUM> and convex end surface <NUM> of body <NUM> of spacing member(s) <NUM> each may slidingly engage with a complementary convex end surface <NUM> and concave end surface <NUM> of the pair of damper pins 252A, 252B adjacent thereto to form frictional joints. Various shapes of mating end surfaces <NUM>, <NUM> are possible.

Referring to <FIG>, where necessary, convex end surface <NUM> and/or concave end surface <NUM> of each damper pin <NUM> may include a retention member <NUM> engaging with a longitudinal end <NUM> of a respective wire mesh member <NUM> to prevent wire mesh member <NUM> from moving and/or compressing relative to a length of the respective body <NUM> of damper pin <NUM>. In one example, retention member <NUM> includes an enlarged surface <NUM> of one of ends <NUM>, <NUM> (<NUM> as shown) that holds wire mesh member <NUM> on body <NUM> against a radial centrifugal force F on, for example, a turbine blade <NUM>. Other forms of retention member <NUM> may also be employed.

<FIG> show cross-sectional views of an alternative embodiment of damper pins <NUM>. In <FIG>, similar to the <FIG> embodiments, body <NUM> of each of damper pins <NUM> may include a retention member <NUM> engaging within mesh opening <NUM> in the respective wire mesh member <NUM> to fix wire mesh member <NUM> relative to a length of the respective body <NUM> of damper pin <NUM>. <FIG> shows a retention member <NUM> in the form of a protrusion <NUM>, similar to that described relative to <FIG>. <FIG> shows a retention member <NUM> in the form of threaded section <NUM>, similar to that described relative to <FIG>. Here, retention member <NUM> includes a threaded section <NUM> on an outer surface of body <NUM> of the respective damper pin <NUM>. Threaded section <NUM> has an outer dimension (ODT) larger than an inner dimension (IDM) (<FIG>) of mesh opening <NUM> of wire mesh member <NUM> to create a larger outer dimension (ODM2) on wire mesh member <NUM> sized for frictionally engage with inner dimension (IDB) of body opening <NUM>.

<FIG> also shows that other shapes than rounded convex and concave ends <NUM>, <NUM> may be employed for the mating surfaces. For example, as shown in <FIG>, ends <NUM>, <NUM> can be planar. <FIG> shows another option in which ends <NUM>, <NUM> are conical or frusto-conical. <FIG> also shows that the position of mating surfaces <NUM>, <NUM>, such as but not limited to convex end surface <NUM> and concave end surface <NUM> can be switched. In <FIG>, in contrast to the arrangement in <FIG>, convex end surface <NUM> is on the radial inner end of body <NUM> and concave end surface <NUM> is on the radially outer end of body <NUM>. Any of the varieties of mating surfaces <NUM>, <NUM> described herein can be switched in this manner.

Damper pins <NUM> also are advantageous to allow vibration damping with contiguous body openings <NUM> having different sizes. In this setting, as shown for example in the schematic cross-sectional view of <FIG>, vibration damping element <NUM> includes contacting members <NUM> having more than one plurality (set) of damper pins 252C, 252D. In the example shown, vibration damping element <NUM> includes first plurality of damper pins 252C in a first body opening 160C, and a second plurality of damper pins 252D in a second, contiguous body opening 160D. First body opening 160C has a different inner dimension than second body opening 160D (e.g., IDB1 < IDB2). Each damper pin 252C, 252D includes a body 260C, 260D, respectively, as previously described. A first wire mesh member 180C surrounds body 260C of at least one of first plurality of damper pins 252C (shown with all three having them and no spacing member). Wire mesh member(s) 180C has a first outer dimension (ODMC) sized to frictionally engage with an inner surface 182C of first body opening 160C having a first inner dimension (IDB1) in turbine nozzle <NUM> or blade <NUM> to damp vibration therein. Each body 260C of damper pins 252C is sized appropriately for wire mesh members 180C.

Vibration damping element <NUM> including contacting members <NUM> also includes second plurality of damper pins 252D with each damper pin 252D having body 260D. A second wire mesh member 180D surrounds body 260D of at least one of the second plurality of damper pins 252D (shown with both pins 252D having them and no spacing member). Each body 260D of damper pins 252D is sized appropriately for wire mesh members 180D. Second wire mesh member(s) 180D have a second outer dimension (ODMD) for frictionally engaging with an inner surface 182D of second body opening 160D in turbine nozzle <NUM> or blade <NUM>. In the example shown, second body opening 160D has a second, larger inner dimension (IDB2) than first inner dimension (IDB1) of first body opening 160C. Despite the different sizes, first body opening 160C and second body opening 160D are contiguous and may share a common longitudinal axis.

Damper pin sets 252C, 252D having different sizes can be advantageous to minimize weight of vibration damping element <NUM>, while still maintaining a desired vibration damping performance. Any number of damper pin sets 252C, 252D may be employed with different sized body openings 160C, 160D. While not shown for clarity, contact members <NUM> may also include any number of spacing members <NUM> (<FIG>).

Although not shown, larger damper pins 252D may engage with and load against smaller damper pins 252C via mating end surfaces <NUM>, <NUM>. However, as shown, larger damper pins 252D may be isolated from smaller damper pins 252C such that larger damper pins 252D do not load against smaller damper pins 252C. The isolation can be created in a variety of ways. In one non-claimed example, shown in <FIG>, second body opening 160D may be configured to engage with an end <NUM> of a terminating one of larger damper pins 252D, e.g., via a tapered surface <NUM> thereof.

As shown in the schematic cross-sectional view of <FIG>, which is a non-claimed example, where it is desirable to lower the weight of vibration damping element <NUM>, at least one contacting member <NUM> may include a hollow region <NUM> defined therein. In <FIG>, hollow regions <NUM> are shown only in damper pins <NUM>, but hollow regions <NUM> are equally applicable to spacing members <NUM>. Hollow regions <NUM> can be applied to any embodiment described herein.

<FIG> shows a schematic cross-sectional view of another non-claimed optional embodiment. Another advantage of damper pins <NUM> is that each pin and respective wire mesh member <NUM> can bear its own weight. Consequently, damper pins <NUM> can be used in a body opening <NUM> in turbine nozzle <NUM> or blade <NUM> that extends at an angle α relative to a radial direction (R) of turbine nozzle <NUM> or blade <NUM>. Angle α can be, for example, any angle between <NUM>°-<NUM>°. As shown in the non-claimed example in <FIG>, damper pins <NUM> can also be used in a body opening <NUM> in turbine nozzle <NUM> or blade <NUM> that extends in a curved manner relative to a radial direction (R) of turbine nozzle <NUM> or blade <NUM>. Any radius of curvature R can be used.

It will be apparent that some embodiments described herein are applicable mainly to rotating turbine blades <NUM> that experience centrifugal force during operation and thus that may require certain structure to maintain high performance vibration damping. That said, any of the above-described embodiments can be part of a turbine nozzle <NUM> or blade <NUM>.

Embodiments of the disclosure provide vibration damping element(s) <NUM> including elongated body(ies) <NUM> or a plurality of damper pins <NUM> with wire mesh member(s) <NUM> to reduce nozzle <NUM> or blade <NUM> vibration with a simple arrangement. A variety of retention systems may be used to maintain a position of wire mesh members <NUM>. Vibration damping system <NUM> does not add much extra mass to nozzle(s) <NUM> or blade(s) <NUM>, and so it does not add additional centrifugal force to blade tip end or require a change in nozzle or blade configuration.

Accordingly, a value modified by a term or terms, such as "about," "approximately" and "substantially," is not to be limited to the precise value specified. Here and throughout the specification and claims, range limitations may be combined and/or interchanged; such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. "Approximately," as applied to a particular value of a range, applies to both end values and, unless otherwise dependent on the precision of the instrument measuring the value, may indicate +/- <NUM>% of the stated value(s).

Claim 1:
A vibration damping element (<NUM>) for a vibration damping system (<NUM>) for a turbine nozzle or blade (<NUM>, <NUM>), comprising:
an elongated body (<NUM>); characterised in that the vibration damping element (<NUM>) further comprises:
a wire mesh member (<NUM>) surrounding the elongated body (<NUM>) and having a first outer dimension in an inoperative state and a second, larger outer dimension in an operative state, wherein in the operative state, the wire mesh member (<NUM>) frictionally engages with an inner surface (<NUM>) of a body opening (<NUM>) in the turbine nozzle or blade (<NUM>, <NUM>) to damp vibration, and in the inoperative state, the wire mesh member (<NUM>) slides freely in the body opening (<NUM>) in the turbine nozzle or blade (<NUM>, <NUM>); and
a retention member (<NUM>) on the elongated body (<NUM>) to fix a first section of the wire mesh member (<NUM>) relative to a length of the elongated body (<NUM>) in the operative state in the body opening (<NUM>) of the turbine nozzle or blade (<NUM>, <NUM>).