Airfoil section using cavity damping

Abstract

To provide an article, such as a turbine blade.SOLUTION: An article, such as a turbine blade, includes an airfoil (20). The airfoil (20) includes a body (21), the body (21) having an elongated internal cavity (26) extending from a tip (29) of the body (21). The cavity (26) is defined by an internal wall within the body (21). At least one elongated damping element is disposed in the elongated internal cavity (26) and frictionally engages the internal wall. Thus, the least one elongated damping element is capable of damping vibrations in the article.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure generally relates to self-damping turbine blades. Further, the present disclosure relates to damping of blades used in turbines.

Background Art

[0002] One concern in turbine operation is that turbine blades tend to be subject to vibration stresses during operation. In many facilities, the turbine is operated under conditions of frequent acceleration and deceleration. During acceleration or deceleration of the turbine, the blades are exposed to vibration stresses at least momentarily, and often at secondary or tertiary frequencies, at a particular frequency. When the blades are exposed to vibration stresses, the amplitude of their vibration can easily increase to a point where it can change the operation.

[0003] The turbine and compressor sections within an axial flow turbine engine generally include a rotor assembly comprising a rotating disk and a plurality of rotor blades circumferentially disposed around the disk. Each blade includes a root, an airfoil, and a platform positioned in a transition area between the root and the airfoil. The root of the blade is received in a complementary-shaped recess within the disk. The platform of the blade extends laterally outward and collectively forms a flow path for fluid passing through the rotor stage. The leading edge of each blade is generally referred to as the leading edge, and the trailing edge is referred to as the trailing edge. The front is defined as upstream behind the gas flow through the engine.

[0004] During operation, the blades may be excited into vibration by several different forcing functions. For example, variations in gas temperature, pressure, and / or density may excite vibrations within the rotor assembly as a whole, particularly within the blade airfoils. Gas exiting upstream of the turbine and / or compressor section in a periodic or "pulsing" manner may also excite undesirable vibrations.

[0005] Blades can be dampened to avoid vibrations. For example, it is known that dampers can be attached to the outer surface of the airfoil. A recognized drawback of adding friction dampers to the outer surface is that the dampers are exposed to the harsh and corrosive environment inside the engine. As soon as the dampers begin to corrode, their effectiveness can be compromised. In addition, corrosion can cause the dampers to detach from the airfoil. [Overview of the project]

[0006] A first aspect of the present disclosure provides an article such as a turbine blade. The blade comprises an airfoil portion, which comprises a body, the body having an elongated internal cavity extending from the tip of the body, the cavity having an inner wall within the body. At least one elongated damping element is disposed within the elongated internal cavity and frictionally engages with the inner wall. Thus, at least one elongated damping element is capable of damping vibrations in the article.

[0007] Further aspects of the present disclosure provide articles such as turbine blades. The blade comprises an airfoil section. The airfoil section comprises a body, the body having an elongated internal cavity extending from the tip of the body. The cavity has an inner wall within the body. At least one elongated damping element is disposed within the elongated internal cavity and frictionally engages with the inner wall. The at least one elongated damping element disposed within the elongated internal cavity comprises an impingement sleeve. The impingement sleeve has at least one contact point projection on each side of the impingement sleeve, each at least one contact point projection frictionally engages with the inner wall of the cavity. Thus, the at least one elongated damping element is capable of damping vibrations in the article.

[0008] Another aspect of the present disclosure provides an article such as a turbine blade. The blade comprises an airfoil section. The airfoil section comprises a body, the body having an elongated internal cavity extending from the tip of the body. The cavity has an inner wall within the body. At least one elongated damping element is disposed within the elongated internal cavity and frictionally engages with the inner wall. The at least one elongated damping element comprises at least one elongated damping bias element. The at least one elongated damping bias element comprises a serpentine spring element that is frictionally fitted into the cavity and in contact with the inner wall of the cavity. Thus, the at least one elongated damping element is capable of damping vibrations in the article.

[0009] The exemplary embodiments of this disclosure are designed to solve the problems described herein and / or other problems not discussed herein.

[0010] These and other features of the Disclosure will be more readily apparent from the following detailed description of various aspects of the Disclosure, in conjunction with the accompanying drawings illustrating various embodiments of the Disclosure. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic side view of a blade according to an embodiment of the present disclosure. [Figure 2] This is a schematic side view of a blade and at least one damping element according to an embodiment of the present disclosure. [Figure 3] This is a schematic side view of at least one damping element in the form of a partial blade and impingement sleeve according to an embodiment of the present disclosure. [Figure 4] This is a schematic upper cross-sectional view of at least one damping element in the form of a blade and an impingement sleeve according to an embodiment of the present disclosure. [Figure 5] This is a schematic side view of at least one damping element in the form of a partial blade and impingement sleeve, according to a particular embodiment of the present disclosure. [Figure 6]This is a further schematic perspective view of at least one damping element in the form of a partial blade and impingement sleeve according to a particular embodiment of the present disclosure. [Figure 7] This is a schematic side view of at least one damping element in the form of a blade and at least one damping bias element according to an embodiment of the present disclosure. [Figure 8] This is a schematic side view of a portion of at least one damping element in the form of a blade and at least one damping bias element according to an embodiment of the present disclosure. [Figure 9] This is a perspective view of a damping bias element according to an embodiment of the present disclosure. [Modes for carrying out the invention]

[0012] Please note that the drawings in this disclosure are not necessarily to scale. The drawings are intended to illustrate only typical embodiments of this disclosure and should not be considered to limit the scope of this disclosure. In the drawings, similar reference numerals represent similar elements between drawings.

[0013] As a first issue, in order to clearly explain the current disclosure, it is necessary to select specific technical terms when referring to and describing relevant mechanical components within a turbine system. Wherever this is done, common industrial terminology will be used and utilized in the same sense as its accepted meaning, whenever possible. Unless otherwise stated, such terminology should be given a broad interpretation consistent with the context of this application and the appended claims. Those skilled in the art will understand that, in many cases, certain components may be referred to using several different or overlapping terms. What may be described herein as a single component may also be included in and referred to in another context as consisting of multiple components. Conversely, what may be described herein as consisting of multiple components may be referred elsewhere as a single component.

[0014] In addition, several descriptive terms may be used in accordance with the rules of this specification, and it will be useful to define these terms at the beginning of this section. These terms and their definitions are as follows, unless otherwise specified. As used herein, “downstream” and “upstream” are terms indicating the direction of fluid flow relative to the working fluid through the turbine system, or, for example, the flow of air through the combustor, or the coolant through one of the turbine component systems. The term “downstream” corresponds to the direction of fluid flow, and the term “upstream” refers to the opposite direction of flow. In reverse flow configurations, it is recognized that the upstream and downstream directions may differ depending on where the component is located in the turbine system. The terms “forward” and “rear” refer to directions unless otherwise specified, with “forward” referring to the front end of the turbine system and “rear” referring to the rear end of the turbine system. Often, it is required to describe components that are in different radial positions with respect to the central axis. The term “radial” refers to movement or position perpendicular to the axis. In such cases, if the first component is located closer to the axis than the second component, this specification states that the first component is “radially inward” or “inward” of the second component. On the other hand, if the first component is located further from the axis than the second component, this specification may state that the first component is “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 about the axis. It will be understood that such terms can be applied in relation to the central axis of a turbine system, for example, the axis of its rotor.

[0015] In addition, as described below, several descriptive terms may be used in accordance with the rules. The terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of any individual component.

[0016] Referring to Figure 1, a turbine blade assembly (hereinafter referred to as a blade) 10 is shown. The blade 10 includes a root 18, an airfoil 20, an airfoil body 21, a tip 29, and a platform 22. The root 18 (often called a dovetail or fir tree) includes a geometric shape that conforms to one geometric shape of a recess in the turbine disk (not shown for the sake of illustration). The fir tree configuration is common and is used in this case for illustrative purposes only and is not intended to limit embodiments in any way.

[0017] In an embodiment, referring to the figures, in Figure 1, the tip 29 defines an opening 25 for an elongated internal cavity 26 (hereinafter referred to as the "cavity," shown as a dashed line in Figure 2) that extends from the tip 29 of the airfoil 20 to the length within the blade 10. This cavity may be as short as extending only to a portion of the span of the airfoil 20, or it may be tall enough to extend completely through the airfoil 20 and the root 18. Furthermore, the cavity 26 is defined by an inner wall 26' (Figure 3) and presents a shape that generally reflects the geometric shape around the body 21 outside the airfoil 20. Alternatively, the cavity 26 may be configured to allow enhanced damping of the blade 10 when at least one damping element is provided, as will be discussed below.

[0018] Although the figures of the embodiments herein show an open tip 29, a cap (not shown) can be added to the tip 29 of the airfoil section 20. The cap can close the cavity 26 after the impingement sleeve 30 is provided in the cavity, as described below.

[0019] Figure 3 shows at least one damping element, and in the illustrated embodiment of Figure 3, an impingement sleeve 30 is provided. The impingement sleeve 30 can be inserted into the cavity 26 of the airfoil section, and the airfoil section 20 is shown with a partial vertical length for purposes of illustration only. In Figure 3, the impingement sleeve 30 includes at least one retaining member. In the embodiment of Figure 3, the at least one retaining member includes at least one contact point protrusion 32 on each side of the impingement sleeve 30.

[0020] The at least one contact point protrusion 32 spaces the impingement sleeve 30 from the inner wall 26' of the cavity 26 and defines a space 27 (see Figure 4). The space 27 surrounds the impingement sleeve 30 and is surrounded by the inner wall 26' of the cavity 26. Thus, by being positioned in this way, the impingement sleeve 30 allows the flow of cooling fluid within the cavity 26 around each of the at least one contact point protrusion 32. Thus, the impingement sleeve 30 and the at least one contact point protrusion 32 reduce the overall size of the cavity 26. Such a reduced size reduces the amount of cooling fluid or cooling air required to keep the airfoil section 20 at an acceptable operating temperature.

[0021] The at least one contact point protrusion 32 is shown in Figures 3, 4, and 5, and other figures, as essentially circular "dimples" on the impingement sleeve 30. This configuration is merely an example of a possible configuration of the at least one contact point protrusion 32. The at least one contact point protrusion 32 can be formed in any configuration or shape that allows the at least one contact point protrusion 32 to engage frictionally with the wall 26' of the cavity 26. Such shapes include, but are not limited to, at least one of conical, rectangular, triangular, pyramidal, and / or polygonal, as long as the at least one contact point protrusion 32 spaces the impingement sleeve 30 from the wall 26' of the cavity 26, provides a frictional engagement therebetween, and dampens the vibration and relative movement of the airfoil section 20.

[0022] Thus, the impingement sleeve 30 partially fills the cavity 26. The impingement sleeve 30, via at least one of its contact point projections 32, engages the side walls of the cavity, establishing a contact load therebetween and maintaining the impingement sleeve 30 spaced apart from the forward and rear areas of the cavity (the front and rear regions of the airfoil 20). Thus, the impingement sleeve 30 and the inner wall 26' of the cavity 26 in these forward and rear areas (the leading and trailing edges) do not contact the impingement sleeve 30 itself directly.

[0023] Furthermore, the embodiment allows the impingement sleeve 30 to extend and occupy as many cavities as possible. This spatial positioning of the impingement sleeve 30 within the cavity 26 allows for enhanced and extended damping, to the extent possible, reduces the amount of cooling fluid or cooling air required for the blade, and can also extend the durability and life of the blade 10 and the associated turbomachine.

[0024] The configuration and engagement of at least one contact point projection 32 of the impingement sleeve 30 with the inner wall 26' of the cavity 26 inherently and naturally define at least one retaining structural member for the impingement sleeve 30 relative to the wall 26' of the cavity 26.

[0025] At least one contact point projection 32 can also act as a turbulent element that provides turbulent mixing, swirling, and desirable flow characteristics to the cooling fluid or cooling air. The resulting flow can forcibly cool the airfoil 20 by a combination of circulating cooling and turbulence, and thus achieve an enhanced cooling effect with the same or less amount of cooling fluid or cooling air.

[0026] The frictional engagement between at least one contact point projection 32 of the impingement sleeve 30 and the inner wall of the cavity 26 allows for damping of the airfoil 20. The impingement sleeve 30 and the frictional engagement can reduce and substantially eliminate vibrations of the airfoil 20 during operation. The vibrations of the airfoil 20 can result from operational use, loads, vibrations, and any stresses that occur during operation, as discussed above. Therefore, by reducing, mitigating, and potentially substantially eliminating vibrations (in some cases), the airfoil 20 should be subjected to fewer harmful forces, stresses, and vibrations. These beneficial reductions of forces, stresses, and vibrations can, according to embodiments, extend and enhance the durability and lifespan of the damped airfoil 20 and blade 10.

[0027] According to the embodiments, the impingement sleeve 30 is inserted into the cavity 26. In some embodiments, the impingement sleeve 30 is inserted into the cavity 26 which extends partially down the length of the body 21 and terminates in front of the platform 22 (Figure 5). In other embodiments, the impingement sleeve 30 is inserted into the cavity 26 which extends down the entire length of the body 21 and terminates at the platform 22. And in some further embodiments, the impingement sleeve 30 is inserted into the cavity 26 which extends partially down the length of the body 21, extends beyond the platform 22 and enters the root 18, and terminates at the root 18 (Figure 6).

[0028] The impingement sleeve 30 and cavity 26 can extend as deep as possible into the body 21 of the blade 10. The feasibility of the depth of the impingement sleeve 30 is not limited, but takes into account various factors such as configuration, material, and dimensions.

[0029] In large blades 20, such as those of large turbines, the blade 10 may include, but is not limited to, a partial span shroud 200 (Figure 5) for stability and operational purposes. The partial span shroud 200 is provided on the airfoil 20 and comprises a pair of partial span connectors 218 extending from the airfoil 20 on both the negative and positive pressure sides of the blade 20, respectively. Each of the pair of partial span shrouds 200 may be sized to complement and engage with a corresponding partial span connector on an adjacent turbine blade 20.

[0030] As shown in Figure 5, this embodiment provides an impingement sleeve 30 that extends partially downward along the length of the body 21 and terminates at a partial span shroud 200 in front of the platform 22. In this embodiment, at least one retaining pin 220 is provided that extends through at least one retaining pin opening 222 within the partial span shroud 200 to secure the impingement sleeve 30 within the cavity 26 at the partial span shroud 200. Each retaining pin 220 can be sized to align with the outer surface of the body 21, in this case the partial span shroud 200, to provide a smooth surface that is essentially coplanar.

[0031] The impingement sleeve 30 may have at least one impingement sleeve through hole 33. The at least one impingement sleeve through hole 33 is aligned with at least one retaining pin opening 222. Thus, a retaining pin 220 inserted into at least one retaining pin opening 222 in the partial span shroud 200 extends through the airfoil body 21, exits through at least one impingement sleeve through hole 33 in the impingement sleeve 30, and enters into at least one opposing retaining pin opening 222 on the opposite side of the airfoil body 21 in the partial span shroud 200. Thus, as the blade 10 rotates during operation, frictional contact of the impingement sleeve 30 via at least one contact point projection 32 to the inner wall of the cavity 26 holds the impingement sleeve 30 inward, and the at least one retaining pin 220 and at least one retaining pin opening 222 engage with the partial span shroud 200 to provide additional fastening.

[0032] In embodiments where the impingement sleeve 30 extends down the length of the body 21 and into the root 18 by the platform 22, a similar configuration with retaining pins 220 can be provided to the root 18. Each retaining pin 220 can again be sized to align with the outer surface of the body 21, in this case the base 18, to provide a smooth surface that is essentially coplanar. In this embodiment, at least one retaining pin 220 is provided extending through at least one retaining pin opening 181 in the base 18 to secure the impingement sleeve 30 in the cavity 26 at the base 18. Thus, during operation of this embodiment, as the blade 10 rotates, frictional contact of the impingement sleeve 30 via at least one contact point projection 32 to the inner wall of the cavity 26 holds the impingement sleeve 30 inward, and at least one retaining pin 220 engages with the base 18, providing additional fastening at at least one retaining pin opening 181.

[0033] The impingement sleeve 30 can be formed from a material compatible with the material on which the blade 10 is formed. For example, the impingement sleeve 30 may include, but is not limited to, superalloys such as GTD-444 (a trademark of General Electric), L605 (a platform material for some blades), CMC material (which can provide lightness and wear resistance), and other such materials. Furthermore, if the material of the impingement sleeve 30 oxidizes to some extent and its oxide has lubricating properties, the lubricating oxidation advantageously allows for further damping of the impingement sleeve 30 and the blade 10.

[0034] In another aspect of the embodiment shown in Figure 7, the cavity 26 of the blade 10 comprises at least one damping bias element 130. The at least one damping bias element 130 comprises a meandering spring element that contacts the inner wall 26' of the cavity 26. In Figure 7, a portion of the body 21 is cut to show two of the at least one damping bias element 130 in the cavity 26 (for viewing purposes only). Although two meandering damping bias elements 130 are shown in Figure 7, embodiments and aspects of the present disclosure include at least one meandering damping bias element 130. Other embodiments and aspects of the present disclosure may also include two or more meandering damping bias elements 130 in the recess. For ease of explanation and to avoid limiting embodiments in any way, the following embodiments will discuss the element 130 as “at least one damping bias element 130”.

[0035] Each of the at least one damping bias element 130 extends from the tip 29 of the body 21 toward the base 18. As described above, in some embodiments, the at least one damping bias element 130 may be inserted into a cavity 26 that extends partially downward along the length of the body 21 and terminates before the platform 22 (this aspect of the embodiment is not shown). In other embodiments, the at least one damping bias element 130 may be inserted into a cavity 26 that extends downward along the entire length of the body 21 and terminates at the platform 22. And in some further embodiments, the at least one damping bias element 130 may be inserted into the cavity 26, extend partially downward along the length of the body 21, pass through the platform 22, enter the root 18, and terminate at the root 18 (Figure 7).

[0036] At least one damping bias element 130 can be described as a meandering, reverse-bending end spring clip. Conventional spring clips have their arm "open" end extending outward to receive an element held by the spring clip, but at least one damping bias element 130 is a reverse-bending end spring clip, as shown herein. Thus, the arm "open" end 136 of arm 135 extends on itself. This configuration of at least one damping bias element 130 provides an enhanced outward bias force (see arrow A in Figures 8 and 9) and a k-factor that enhances the force against the wall 26', as determined by Hooke's Law. Thus, the configuration of at least one damping bias element 130 and its spring force (discussed below) makes it possible for at least one damping bias element 130 to inherently and naturally define at least one retaining structural member against the wall 26' of the cavity 26.

[0037] At least one damping bias element 130 can be retained within the cavity 26 by its outward bias force pushing against the wall 26' of the cavity 26, as embodied herein. Figure 8 shows the tip 29 of the blade 10 as embodied herein. At least one damping bias element 130 (shown in detail in Figure 9) is subjected to a compressive force when in contact with the wall 26' while within the cavity 26. Thus, the outward bias force of at least one damping bias element 130 can dampen vibrations, stresses, etc., during the operation of the blade 10.

[0038] Referring to Figure 9, at least one damping bias element 130 comprises a base 132 and a base leg round 131. Each base leg round 131 defines a bend to form a return portion 133. Each return portion 133 extends inward toward the “mid-section” of the base 132, but at a distance X from the base. The return portions 133 extending from each base leg 131 bend over themselves, forming an inner bend 134. From the inner bend 134, at least one damping bias element 130 extends outward or backward from the innermost extent of the inner bend 134, defining a set of arms 135. The arms 135 are concave opposite to each other, and their radii are essentially aligned with the midpoint of the base 132 at a distance Y from the base 132. Essentially, as the arms begin to bend toward each other, they form a circular area. The arm "open" end 136 of at least one damping bias element 130 arm 135 is bent back into a circular shape toward the interior of the formed circular area.

[0039] At least one damping bias element 130, when positioned within the cavity, contacts the wall 26' at the outermost points of the base leg round 131 and the arm 135, all of which, according to the embodiment, form at least one retaining structural member. Thus, each at least one damping bias element 130 makes four contact points with the inner wall 26'. The ends 136 of the arm are closer to each other when compressed within the cavity 26 (as shown in Figure 8) than when in an uncompressed state outside the cavity 26 (as shown in Figure 9, for example). This aspect of the embodiment is best illustrated in Figure 8.

[0040] When two or more at least one damping bias elements 130 are provided in the cavity 26, each of the at least one damping bias elements 130 acts independently of the others. Also, when two or more at least one damping bias elements 130 are provided, the two or more at least one damping bias elements 130 may have similar k coefficients. In other embodiments, when two or more at least one damping bias elements 130 are provided, each of the two or more at least one damping bias elements 130 may have different k coefficients that provide gradient or differential damping characteristics to the blade 10.

[0041] At least one damping bias element 130 can be coupled or attached to one or more points on at least one of the airfoil section 20 and the cavity 26. The coupling or attachment can be achieved by a suitable physical bonding system, including, but not limited to, mechanical bonding, metallurgical (welding or brazing) bonding, any adhesive, etc., as known now or in the future.

[0042] Furthermore, as embodied herein, at least one damping bias element 130 can be retained within the cavity 26 by coupling with a cap 129. The cap 129 is attached to the body 21 of the airfoil section 20 at its tip 29. When the cap 129 is attached to the cavity 26 and closes the cavity 26, it does not allow the at least one damping bias element 130 to move out of the cavity 26. Also, since the cap 129 can contact the end of the at least one damping bias element 130 at its tip 29, it is possible to restrict the movement of the at least one damping bias element 130 in all directions, including but not limited to outside the cavity 26, by, for example, touching the at least one damping bias element 130 and restricting its movement.

[0043] Furthermore, as shown in Figures 7 and 8, considering the volume of at least one damping bias element 130 within the cavity, the cavity 26 retains space both within and around the at least one damping bias element 130. Therefore, the cooling fluid or cooling air flowing through the cavity 26 is not obstructed by the at least one damping bias element 130 within the cavity.

[0044] Each at least one damping bias element 130 acts to reinforce the wall 26' of the blade body 21. The reinforcement is achieved by the expansion pressure from each at least one retaining structural member of the at least one damping bias element 130 against the inner wall 26' of the cavity 26. This pressure controls the damping, stress, vibration, etc. that the blade may experience.

[0045] The technical terms used herein are for the sole purpose of describing specific embodiments and are not intended to limit this disclosure. Where used herein, the singular forms “a,” “an,” and “the” are intended to include the plural unless otherwise specified. Where used herein, the terms “comprise” and / or “comprising” express the existence of the described features, integers, steps, actions, elements, and / or components, but do not exclude the existence or addition of one or more other features, integers, steps, actions, elements, components, and / or sets thereof. “Optional” or “optional” means that the events or circumstances described later may or may not occur, and this statement includes both instances in which the event occurs and instances in which it does not.

[0046] When an element or layer is referred to as “on top of,” “engaged,” “disengaged,” “connected,” or “joined” with respect to another element or layer, it may be directly on top of, engaged with, connected to, or joined to the other element or layer, or there may be an intervening element or layer. Conversely, when an element is referred to as “directly on top of,” “directly engaged,” “directly connected,” or “directly joined” with respect to another element or layer, there may be no intervening element or layer. Other words used to describe relationships between elements should be interpreted similarly (e.g., “between” versus “directly between,” “adjacent to” versus “directly adjacent to.”). As used herein, the term “and / or” includes any of the related enumerated items and any combination of one or more of them.

[0047] Throughout this specification and the claims, the approximation language can be applied to modify any quantitative expression that may vary to a reasonable extent without altering the fundamental function of the expression. Thus, values ​​modified by terms such as “approximately,” “about,” and “substantially” are not limited to the exact value specified. In at least some examples, the approximation language may correspond to the precision of the instrument used to measure the value. Herein, and throughout this specification and the claims, limitations on ranges are interchangeable and / or substitutable, and unless the context and wording specifically indicate otherwise, such ranges are identified and include all subranges encompassed therein. “About,” applied to a particular value within a range, may indicate + / - 10% of the stated value, unless applied to the values ​​at both ends and particularly dependent on the precision of the instrument used to measure the value.

[0048] All corresponding structures, materials, actions, and equivalents of all elements of means-plus-function or step-plus-function in the following claims are intended to encompass all structures, materials, or actions for performing that function in combination with any other specifically claimed elements. The descriptions in this disclosure are presented for illustrative and explanatory purposes and are not intended to be exhaustive or to limit the disclosure to the forms disclosed herein. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of this disclosure. These embodiments have been selected and described in order to best illustrate the principles and practical applications of this disclosure and to enable other those skilled in the art to understand the various embodiments of this disclosure with various modifications to suit specific intended uses. [Explanation of Symbols]

[0049] 10 blades 18. Root, base 20 Turbine blades, large blades, airfoil sections 21 Airfoil section 22 platforms 25 Opening 26. Elongated internal cavity, recess 26' internal wall 27 Space 29 Tip 30 impingement sleeves 32 Contact point protrusion 33 Impingement sleeve through hole 129 Cap 130 Damping Bias Element 131 Base Leg Round 132 base 133 Return section 134 Inner bend 135 Arm 136 End 181 Retaining pin opening 200 Partial Span Shroud 218 Partial Span Connector 220 retaining pins 222 Retaining pin opening A. Bias X distance Y distance

Claims

1. An article, and said article is A wing-shaped portion (20) including a main body (21), wherein the main body (21) has an elongated internal cavity (26) extending from the tip (29) of the main body (21), and the cavity (26) is defined by an inner wall (26') inside the main body (21), At least one elongated damping element, which is disposed within the elongated internal cavity (26) and frictionally engages with the inner wall (26') and is therefore capable of damping vibrations, It is equipped with, An article wherein the at least one elongated damping element comprises at least one retaining structural member, the at least one elongated damping element is frictionally positioned within the elongated internal cavity (26) by frictional fitting of the at least one retaining structural member to the inner wall (26') of the cavity (26), the at least one elongated damping element positioned within the elongated internal cavity (26) comprises a hollow impingement sleeve (30), the at least one retaining member of the impingement sleeve (30) comprises a plurality of contact point protrusions (32) on the impingement sleeve (30), each of the plurality of contact point protrusions (32) frictionally engages with the inner wall (26') of the cavity (26), and each of the plurality of contact point protrusions (32) is a circular dimple.

2. The article according to claim 1, wherein the plurality of contact point protrusions (32) define a space (27) that separates the impingement sleeve (30) from the inner wall (26') of the cavity (26), and the space (27) surrounds the impingement sleeve (30) and is surrounded by the inner wall (26') of the cavity (26).

3. The article according to claim 2, wherein the plurality of contact point protrusions (32) engage with the side walls of the inner wall (26') of the cavity (26) to keep the impingement sleeve (30) away from the front and rear areas of the cavity (26), and the impingement sleeve (30) and the inner wall (26') of the cavity (26) do not come into direct contact with each other in the front and rear areas.

4. The article according to claim 1, wherein the airfoil (20) includes a tip (29), a platform (22), and a root (18), the platform (22) and the root (18) are located at the opposite end of the airfoil (20) from the tip (29), the cavity (26) extends from the tip (29) of the airfoil (20) toward the platform (22) and the root (18), and the at least one elongated damping element extends longitudinally from the tip (29) toward the platform (22) and the root (18).

5. The article according to claim 4, wherein the at least one elongated damping element extends longitudinally from the tip (29) and terminates at or below the platform (22).

6. The article according to claim 4, wherein the at least one elongated damping element extends longitudinally from the tip (29) and extends into the root (18).

7. The airfoil portion (20) comprises a tip (29) and a platform (22), the platform (22) being at the end of the airfoil portion (20) opposite to the tip (29), and the cavity (26) extending from the tip (29) of the airfoil portion (20) toward the platform (22), The article according to claim 1, wherein the airfoil (20) further comprises at least one partial span shroud (200) on the body (21), the at least one partial span shroud (200) positioned between the tip (29) of the airfoil (20) and the platform (22), and the at least one elongated damping element extending from the tip (29) of the airfoil (20) and terminating in the cavity (26) in the partial span shroud (200).

8. The article according to claim 7, wherein the at least one partial span shroud (200) further comprises at least one retaining pin opening (222), and the impingement sleeve (30) comprises at least one impingement sleeve (30) through hole (33) aligned with the at least one retaining pin opening (222), and the article further comprises retaining pins (220) configured to extend through the at least one retaining pin opening (222) in the at least one partial span shroud (200) and the at least one impingement sleeve (30) through hole (33) in the impingement sleeve (30) for securing the at least one impingement sleeve (30) to the partial span shroud (200) of the airfoil portion (20).

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