Damper element having spring-suspended bearing member for vibration damping system for turbine blades

Abstract

The present disclosure relates to a damper element (270) for a vibration damping system (220) that can be used in a body opening (160) in a rotating blade in a turbine (108). The damper element (270) includes: a base member (272) having an axially fixed position within the body opening (160); and a spring suspended support member (274) having a spring (280) fixedly coupled to the base member (272) at a first end (282) of the spring (280) and a support member (286) coupled to a second end (288) of the spring (280). The support member (286) frictionally engages the bearing surface (290) to attenuate vibrations when the spring (280) is in an elastically extended state affected by centrifugal force caused by rotation of the rotating blade above a predefined rotational speed. The spring-suspended support member (274) provides a friction-based vibration damping interface that is subjected to the effect of the reduction in the centrifugal force of the rotating blade (114) by providing a reaction force reduction using a spring (280).

Description

Technical Field

[0001] The present disclosure generally relates to damping vibrations in rotating blades. More particularly, the present disclosure relates to a vibration damping system including a plurality of damper elements each having a spring-suspended support member. Background Art

[0002] One problem in turbine operation is the tendency of rotating turbine blades to be subjected to vibration stress during operation. In many facilities, turbines operate under conditions of frequent acceleration and deceleration. During acceleration or deceleration of the turbine, the airfoil of the blade is temporarily subjected to vibration stress at least at certain resonant frequencies, and in many cases, subjected to vibration stress at secondary or tertiary frequencies. The nozzle airfoil is also subjected to similar vibration stress. For example, changes in gas temperature, pressure and / or density may excite vibrations throughout the rotor assembly, especially in the blade airfoil. Gas leaving the turbine and / or compressor section upstream in a periodic or "pulsating" manner may also excite undesirable vibrations. When the airfoil is subjected to vibration stress, its vibration amplitude may easily accumulate to a degree that may negatively affect the operation and / or component life of the gas turbine. Previously, although stacked solid damper elements in turbine blades have been used to attenuate vibrations, centrifugal forces may cause the damper elements to lock together, thereby reducing or eliminating the ability of the damper elements to attenuate vibrations. Summary of the invention

[0003] All aspects, examples and features mentioned below can be combined in any technically possible way.

[0004] An aspect of the present disclosure provides a damper element of a vibration damping system in a body opening in a rotating blade in a turbine, the damper element comprising: a base member having an axially fixed position within the body opening; and a spring-suspended support member having a spring fixedly coupled to the base member at a first end of the spring and a support member coupled to a second end of the spring; wherein the spring is configured to achieve an elastically extended state under the influence of centrifugal forces caused by rotation of the rotating blade at a speed above a predefined rotational speed, and wherein the elastically extended state of the spring causes the support member to frictionally engage a first support surface to dampen vibrations.

[0005] Another aspect of the present disclosure includes any of the aforementioned aspects, and the spring constant of the spring and the total mass of the support member and the spring are configured to allow the support member to move from a position disengaged from the first support surface to a frictional engagement with the first support surface in response to a centrifugal force caused by rotation of the rotating blade at a speed higher than a predefined rotational speed.

[0006] Another aspect of the disclosure includes any of the preceding aspects, and the base member has a first side and a second side, and the spring includes a plurality of partial helical coils extending from the first side of the base member to the support member.

[0007] Another aspect of the present disclosure includes any of the aforementioned aspects, and each partial spiral coil includes a first end and a second end, wherein the first end is connected to the first side of the base member at a first circumferential position relative to the central axis of the base member, and the second end is connected to the support member at a second circumferential position relative to the central axis of the base member that is different from the first circumferential position.

[0008] Another aspect of the disclosure includes any of the foregoing aspects, and the first end of each partial helical coil is coupled to the first side of the base member at a perpendicular angle, and the second end of each partial helical coil is coupled to the support member at a perpendicular angle.

[0009] Another aspect of the present disclosure includes any of the foregoing aspects and further includes a positioning member having a first end and a second end, the positioning member coupled to and extending from a first side of the base member at the first end of the positioning member, the positioning member extending adjacent the spring.

[0010] Another aspect of the present disclosure includes any of the aforementioned aspects, and the damper element is a first damper element among a plurality of identical damper elements arranged in a stacked configuration; wherein a first support surface engaged by a support member of the first damper element is located on a second side of a base member adjacent to the damper element, and wherein a second end of the positioning member is configured to frictionally engage a second support surface on the second side of the base member adjacent to the damper element to attenuate vibrations.

[0011] Another aspect of the present disclosure includes any of the aforementioned aspects, and the positioning member is configured to axially fix the base member in position within the body opening relative to an adjacent damper element among the plurality of damper elements, and the spring positions the support member to: be at a certain distance from a first support surface of the adjacent damper element, wherein the rotating blade rotates at a speed lower than a predefined rotational speed and the spring is in a non-fully extended state; and frictionally engage the first support surface of the adjacent damper element to attenuate vibrations, wherein the rotating blade rotates at a speed higher than a predefined rotational speed and the spring is in an elastically extended state.

[0012] Another aspect of the disclosure includes any of the foregoing aspects, and the first bearing surface is located on one of: a side of a base member adjacent to the damper element and an end surface of a body opening in the rotating blade.

[0013] Another aspect of the present disclosure includes any of the aforementioned aspects, and the base member, the spring, and the support member are additionally manufactured and integrally coupled.

[0014] Another aspect of the present invention includes a vibration damping system for a rotating blade of a turbine, the vibration damping system comprising: a plurality of stacked damper elements for positioning in a body opening defined in the rotating blade, each damper element comprising: a base member having an axially fixed position within the body opening; and a spring-suspended support member having a spring fixedly coupled to the base member at a first end of the spring and a support member coupled to a second end of the spring; wherein, when the spring is in an elastically extended state under the influence of centrifugal forces caused by rotation of the rotating blade at a speed above a predefined rotational speed, the support member frictionally engages a first support surface to dampen vibrations.

[0015] Another aspect of the present disclosure includes any of the aforementioned aspects, and the spring constant of the spring and the total mass of the support member and the spring are configured to allow the support member to move from a position disengaged from the first support surface to a frictional engagement with the first support surface in response to a centrifugal force caused by rotation of the rotating blade at a speed higher than a predefined rotational speed.

[0016] Another aspect of the disclosure includes any of the preceding aspects, and the base member has a first side and a second side, and the spring includes a plurality of partial helical coils extending from the first side of the base member to the support member.

[0017] Another aspect of the present disclosure includes any of the aforementioned aspects, and each partial spiral coil includes a first end and a second end, wherein the first end is connected to the first side of the base member at a first circumferential position relative to the central axis of the base member, and the second end is connected to the support member at a second circumferential position relative to the central axis of the base member that is different from the first circumferential position.

[0018] Another aspect of the disclosure includes any of the foregoing aspects, and the first end of each partial helical coil is coupled to the first side of the base member at a perpendicular angle, and the second end of each partial helical coil is coupled to the support member at a perpendicular angle.

[0019] Another aspect of the present disclosure includes any of the foregoing aspects, and each damper element further includes a positioning member having a first end and a second end, the positioning member being coupled to a first side of the base member at the first end of the positioning member and extending from the first side, the positioning member extending adjacent to the spring.

[0020] Another aspect of the present disclosure includes any of the aforementioned aspects, and the first bearing surface frictionally engaged by the first damper element is located on a second side of a base member of a second adjacent damper element opposite to the first side of the base member of the second adjacent damper element, and wherein a positioning member of the first damper element is configured to frictionally engage with a second bearing surface of the second adjacent damper element on the second side of the base member of the second adjacent damper element to attenuate vibrations, the positioning member of the first damper element axially fixes the base member of the second adjacent damper element in position within the body opening, and a spring of the first damper element positions the supporting member of the first damper element to: be at a distance from the first bearing surface, wherein the rotating blades rotate at a speed lower than a predefined rotational speed and the spring is in an incompletely extended state; and frictionally engage the first bearing surface to attenuate vibrations, wherein the rotating blades rotate at a speed higher than a predefined rotational speed and the spring is in an elastically extended state.

[0021] Another aspect of the disclosure includes any of the foregoing aspects, and the first bearing surface is located on one of: a side of a base member adjacent to the damper element and an end surface of a body opening in the rotating blade.

[0022] Another aspect of the present invention relates to a vibration damping system for a rotating blade in a turbine, the vibration damping system comprising: a plurality of stacked damper elements for positioning in a body opening defined in the rotating blade, each damper element comprising: a base member having a first side and a second side; a spring having a first end and a second end, the spring being coupled to the first side of the base member at the first end of the spring; a support member being coupled to the second end of the spring; and a positioning member having a first end and a second end, the positioning member being coupled to the first side of the base member at the first end of the positioning member and extending adjacent to the spring, and wherein the spring positions the support member: at a distance from a first bearing surface, wherein the rotating blade rotates at less than a predefined rotational speed and the spring is in a non-fully extended state; and frictionally engaging the first bearing surface to dampen vibrations, wherein the spring is in an elastically extended state under the influence of centrifugal forces caused by the rotation of the rotating blade at more than the predefined rotational speed.

[0023] Another aspect of the disclosure includes any of the foregoing aspects and, for all but a radially outermost damper element of the plurality of stacked damper elements in the body opening, the first bearing surface includes a second side of the base member adjacent the damper element.

[0024] Another aspect of the disclosure includes any of the foregoing aspects and, for a radially outermost damper element of the plurality of stacked damper elements in the body opening, the first bearing surface includes an end surface of the body opening defined in the rotating blade.

[0025] Another aspect of the present disclosure includes a damper element for a vibration damping system in a body opening in a rotating blade in a turbine, the damper element comprising: a base member having an axially fixed position within the body opening; and a spring-suspended support member comprising: a coil spring fixedly coupled to the base member at a center of the coil spring; and a support member coupled to a first side of the coil spring at an outer periphery of the support member, wherein the support member extends radially distally from the first side of the coil spring; wherein, when the coil spring is in an elastically extended state under the influence of centrifugal forces caused by the rotation of the rotating blade at a speed higher than a predefined rotational speed, the support member frictionally engages the first support surface to dampen vibrations.

[0026] Another aspect of the present disclosure includes any of the aforementioned aspects, and the spring constant of the coil spring and the total mass of the support member and the coil spring are configured to allow the coil spring to move from a position disengaged from the first support surface to a frictional engagement with the first support surface in response to centrifugal force caused by rotation of the rotating blade at a speed higher than a predefined rotational speed.

[0027] Another aspect of the present disclosure includes any of the aforementioned aspects, and the damper element is a first damper element among a plurality of identical damper elements arranged in a stacked configuration; wherein a first supporting surface engaged by a supporting member of the first damper element is one of: a second side of a disc spring of a second adjacent damper element opposite to the first side of the disc spring of the second adjacent damper element, and an end surface of the main body opening.

[0028] Another aspect of the disclosure includes any of the foregoing aspects, and the base member includes an elongated body having a first end surface thereof configured to mate with a second end surface of the base member adjacent the damper element.

[0029] Another aspect of the present disclosure includes any of the aforementioned aspects, and the base member further includes a locating collar disposed concentrically with the elongated body and abutting the second side of the coil spring.

[0030] Another aspect of the present disclosure includes any of the aforementioned aspects, and the base member, the coil spring, and the support member are additionally manufactured and integrally coupled.

[0031] Another aspect of the present invention includes a vibration attenuation system for a rotating blade, the vibration attenuation system comprising: a plurality of damper elements for positioning in a stacked arrangement in a body opening defined in the rotating blade, each damper element comprising: a base member having an axially fixed position within the body opening; and a spring-suspended support member comprising: a coil spring fixedly coupled to the base member at a center of the coil spring; and a support member coupled to a first side of the coil spring at an outer periphery of the support member, wherein the support member extends radially distally from the first side of the coil spring; wherein, when the coil spring is in an elastically extended state due to the influence of centrifugal forces caused by the rotation of the rotating blade at a speed higher than a predefined rotational speed, the support member frictionally engages the first support surface to attenuate vibrations.

[0032] Another aspect of the present disclosure includes any of the aforementioned aspects, and the spring constant of the coil spring and the total mass of the support member and the coil spring are configured to allow the support member to move from a position disengaged from the first support surface to a frictional engagement with the first support surface in response to a centrifugal force caused by rotation of the rotating blade at a speed higher than a predefined rotational speed.

[0033] Another aspect of the present disclosure includes any of the aforementioned aspects, and the plurality of damper elements include a first damper element and a second adjacent damper element; wherein the first supporting surface engaged by the supporting member of the first damper element is one of: a second side of the disc spring of the second adjacent damper element opposite to the first side of the disc spring of the second adjacent damper element, and an end surface of the main body opening.

[0034] Another aspect of the disclosure includes any of the foregoing aspects, and the base member includes an elongated body having a first end surface thereof configured to mate with a second end surface of the base member adjacent the damper element.

[0035] Another aspect of the present disclosure includes any of the aforementioned aspects, and the base member further includes a locating collar disposed concentrically with the elongated body and abutting the second side of the coil spring.

[0036] Another aspect of the present disclosure includes any of the aforementioned aspects, and a plurality of damper elements are additively manufactured and integrally coupled.

[0037] Another aspect of the present disclosure includes any of the aforementioned aspects, and the base member, the disc spring, and the support member of each damper element are additively manufactured and integrally coupled.

[0038] Another aspect of the disclosure includes any of the foregoing aspects, and a support member of a radially outermost damper element of a plurality of damper elements in the body opening is frictionally engaged with an end surface of the body opening defined in the rotating blade.

[0039] Another aspect of the present invention includes a vibration damping system for a rotating blade in a turbine, the vibration damping system comprising: a plurality of stacked damper elements for positioning in a body opening defined in the rotating blade, each damper element comprising: a base member having an axially fixed position within the body opening; and a spring-suspended support member comprising: a coil spring fixedly coupled to the base member at a center of the coil spring; and a support member coupled to a first side of the coil spring at a periphery of the support member, wherein the support member extends radially distally from the first side of the coil spring; wherein the coil spring of a first damper element of the plurality of damper elements positions the support member of the first damper element: at a distance from a first bearing surface, wherein the rotating blade rotates at less than a predefined rotational speed and the coil spring is in a non-fully extended state; and frictionally engages the first bearing surface to damp vibrations, wherein the coil spring of the first damper element is in an elastically extended state under the influence of centrifugal forces caused by the rotation of the rotating blade at more than the predefined rotational speed.

[0040] Another aspect of the present disclosure includes any of the aforementioned aspects, and the first bearing surface is one of: a second side of the coil spring of the second adjacent damper element opposite to the first side of the coil spring of the second adjacent damper element, and an end surface of the body opening.

[0041] Another aspect of the present disclosure includes any of the preceding aspects, and the base member further includes a locating collar abutting the second side of the coil spring.

[0042] Two or more aspects described in this disclosure (including those described in this summary) can be combined to form implementations not specifically described herein.

[0043] The details of one or more implementations are set forth in the drawings and description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] These and other features of the present disclosure will be more readily understood from the following detailed description of various aspects of the present disclosure taken in conjunction with the accompanying drawings which depict various embodiments of the present disclosure, wherein:

[0045] Figure 1 shows a cross-sectional view of an illustrative turbomachine in the form of a gas turbine system including a turbine section;

[0046] Figure 2 The embodiment according to the present disclosure is shown as Figure 1 a cross-sectional view of a portion of an exemplary turbine section for use with a turbine of;

[0047] Figure 3 shows a perspective view of an exemplary turbine blade including a vibration damping system according to an embodiment of the present disclosure;

[0048] Figure 4 shows a schematic cross-sectional view of a turbine blade having a vibration damping system including a plurality of damper elements according to an embodiment of the present disclosure;

[0049] Figure 5 shows a schematic cross-sectional view of a turbine blade having a vibration damping system including a plurality of damper elements according to an embodiment of the present disclosure;

[0050] Figure 6 The embodiment according to the present disclosure is shown as follows Figure 4 and Figure 5 A cross-sectional view of a damper element shown in a vibration damping system;

[0051] Figure 7 The embodiment according to the present disclosure is shown Figure 6 A perspective view of a damper element;

[0052] Fig. 8A shows a cross-sectional view of a vibration damping system including a plurality of damper elements in a first position according to an embodiment of the present disclosure;

[0053] Figure 8B shows a cross-sectional view of a vibration damping system including a plurality of damper elements in a second position according to an embodiment of the present disclosure;

[0054] Fig. 9 shows a cross-sectional view of a damper element according to other embodiments of the present disclosure;

[0055] Fig.10 shows a schematic diagram of a rotating blade and damper element according to an embodiment of the present disclosure, the schematic diagram illustrating the relevant forces in the operation of the vibration damping system;

[0056] Fig.11A illustrates a cross-sectional view of a vibration damping system including a plurality of damper elements in a first position according to other embodiments of the present disclosure;

[0057] Fig. 11B illustrates a cross-sectional view of a vibration damping system including a plurality of damper elements in a second position according to other embodiments of the present disclosure;

[0058] Fig.12 shows a cross-sectional view of a vibration damping system including a plurality of damper elements according to another embodiment of the present disclosure;

[0059] Fig.13 shows a schematic cross-sectional view of a turbine blade having a vibration damping system including a plurality of damper elements according to other embodiments of the present disclosure;

[0060] Fig.14 shows a schematic cross-sectional view of a turbine blade having a vibration damping system including a plurality of damper elements according to other embodiments of the present disclosure;

[0061] Fig.15 The embodiment according to the present disclosure is shown as follows Fig.13 and Fig.14 A side view of a damper element shown in the vibration damping system;

[0062] Fig.16 An additional embodiment according to the present disclosure is shown. Fig.15 A perspective view of a damper element;

[0063] Fig.17A An embodiment of the present disclosure includes a first position Fig.15 A side view of a vibration attenuation system having a plurality of damper elements;

[0064] Fig. 17B An embodiment of the present disclosure includes a Fig.15 A side view of a vibration attenuation system having a plurality of damper elements;

[0065] Fig.18A An embodiment of the present disclosure includes a first position Fig.15 an enlarged side view of a vibration damping system having a plurality of damper elements; and

[0066] Fig.18B An embodiment of the present disclosure includes a Fig.15 An enlarged side view of a vibration damping system with multiple damper elements.

[0067] It should be noted that the drawings of the present disclosure are not necessarily drawn to scale. The drawings are intended to depict only typical aspects of the present disclosure and therefore should not be considered to limit the scope of the present disclosure. In the drawings, like numbers represent like elements between drawings. DETAILED DESCRIPTION

[0068] First, in order to clearly describe the subject matter of the present disclosure, it will be necessary to select certain terms when referring to and describing the relevant machine components within the turbine. To the extent possible, common industry terms will be used and adopted in a manner consistent with the accepted meaning of the terms. Unless otherwise stated, such terms should be given a broad interpretation consistent with the context of the present application and the scope of the appended claims. A person of ordinary skill in the art will understand that several different or overlapping terms may be used to refer to a particular component. An object that may be described as a single part in this article may include multiple parts and be referenced as consisting of multiple parts in another context. Alternatively, an object that may be described as including multiple parts in this article may be referred to as a single part elsewhere.

[0069] In addition, several descriptive terms may be used regularly throughout this document, and it should prove helpful to define these terms at the beginning of this section. It is often necessary to describe parts that are arranged at different radial positions relative to a central axis. The term "radial" refers to movement or position perpendicular to the axis. For example, if a first component is closer to the axis than a second component, this document will describe the first component as being "radially inward" along the second component or on the "inside" of the second component. On the other hand, if the first component resides farther away from the axis than the second component, this document may describe the first component as being "radially outward" or "outside" of the second component. The term "axial" refers to movement or position parallel to the axis. Finally, the term "circumferential" refers to movement or position around the axis. It should be understood that such terms can be applied relative to the central axis of the damper element or the central axis of the turbine.

[0070] In addition, several descriptive terms may be used regularly herein, as described below. The terms "first," "second," and "third" may be used interchangeably to distinguish one component from another and are not intended to indicate the position or importance of individual components.

[0071] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "one", "a kind of" and "the" are intended to also include plural forms, unless the context clearly indicates otherwise. It will be further understood that when used in the specification, the terms "include" and / or "comprising" specify the presence of stated features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or their groups. "Optional" or "optionally" means that the event or situation described subsequently may or may not occur, or the parts or elements described subsequently may or may not exist, and the description includes the situation where the event occurs or the parts exist and the situation where the event does not occur or the parts do not exist.

[0072] Where an element or layer is referred to as being "on," "engaged to," "connected to," or "coupled to," it may be directly on, engaged to, connected to, or coupled to, or there may be intervening elements or layers. In contrast, when an element is referred to as being "directly on," "directly engaged to," "directly connected to," or "directly coupled to," there are no intervening elements or layers. Other words used to describe relationships between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent" versus "immediately adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0073] Embodiments of the present disclosure provide a damper element and a vibration damping system for turbine blades. The damper element for the vibration damping system can be used in a body opening in a rotating blade in a turbine. The damper element includes: a base member having an axial fixed position within the body opening; and a spring-suspended support member having a spring fixedly coupled to the base member at a first end of the spring and a support member coupled to a second end of the spring. When the spring is in an elastically extended state under the influence of centrifugal forces caused by the rotation of the rotating blade at a speed higher than a predefined rotation, the support member frictionally engages the support surface to dampen vibrations. The spring-suspended support member provides a first friction-based vibration damping interface that is subjected to the influence of a reduction in centrifugal forces (i.e., gravitational equivalent (g-force)) formed by the rotating blade by using a spring to provide a reaction force reduction. When the rotating blade rotates at a speed lower than a predefined rotation, the spring-suspended support member remains disengaged from the support surface.

[0074] In certain embodiments, the damper element may be provided with a spring-suspended support member alone, such that any friction-based vibration attenuation provided occurs under less than the full effects of centrifugal forces. In other embodiments, the damper element may include a spring-suspended support member for providing a first friction-based vibration attenuation interface without the full effects of centrifugal forces, and other auxiliary mechanisms for providing a second friction-based vibration attenuation interface that is subject to all centrifugal forces of the rotating blades. In this latter embodiment, the spring-suspended support member still provides the first friction-based vibration attenuation interface in the event that the centrifugal forces exceed the ability of one or more of the auxiliary mechanisms to continue to provide friction-based vibration attenuation.

[0075] The damper element can be customized in terms of overall size, spring constant, support member and / or spring mass, and other characteristics, to work under a limited centrifugal force present at a predefined rotational speed of the rotating blade. The predefined rotational speed and therefore the centrifugal force can be user-defined. In a non-limiting example, the predefined rotational speed can be 75% of the rotational speed of the rotating blade when the turbine is fully loaded. In this way, vibration damping can occur during acceleration of the rotating blade (e.g., early in the turbine startup process) and during deceleration of the rotating blade (e.g., during the turbine shutdown process). Even at 100% rotational speed when the turbine is fully loaded, the centrifugal force observed by the friction engagement surface of the first friction-based vibration damping interface remains below the total centrifugal force. Therefore, although other vibration damping interfaces are rendered inoperative due to centrifugal force, this vibration damping may also occur. The vibration damping system utilizes a simple arrangement to reduce blade vibration and does not add too much additional mass to the blade. Therefore, the vibration damping system and the damper element do not increase the total centrifugal force against the tip end of the blade or do not require changes in the blade configuration.

[0076] With reference to the accompanying drawings, Figure 1 is a cross-sectional view of an exemplary machine including a turbine to which the teachings of the present disclosure may be applied. Figure 1 , a turbomachine 90 in the form of a combustion turbine or gas turbine (GT) system 100 (hereinafter referred to as "GT system 100") is shown. GT system 100 includes a compressor 102 and a combustor 104. Combustor 104 includes a combustion region 105 and a fuel nozzle portion 106. GT system 100 also includes a turbine 108 (i.e., an extended turbine or turbine section) and a common compressor / turbine shaft 110 (hereinafter referred to as "rotor 110").

[0077] GT system 100 may be, for example, a 7HA.03 engine commercially available from General Electric Company, Greenville, SC. ​​The present disclosure is not limited to any one particular GT system and may be implemented with other engines, including, for example, General Electric Company's HA, F, B, LM, GT, TM, and E-class engine models, as well as engine models from other companies. More importantly, the teachings of the present disclosure are not necessarily applicable only to turbines in GT systems, and may be applied to virtually any type of industrial machine or other turbine, such as steam turbines, jet engines, compressors (e.g., Figure 1 ), a turbofan, a turbocharger, etc. Therefore, reference to the turbine 108 of the GT system 100 is for descriptive purposes only and is not limiting.

[0078] Figure 2 A cross-sectional view of an exemplary portion of turbine 108 is shown. In the example shown, turbine 108 includes a Figure 1 1 and 2. The GT system 100 of FIG. 1 is used with four stages L0-L3. The four stages are referred to as L0, L1, L2, and L3. Stage L0 is the first stage and is the smallest stage (in the radial direction) of the four stages. Stage L1 is the second stage and is disposed adjacent to the first stage L0 in the axial direction. Stage L2 is the third stage and is disposed adjacent to the second stage L1 in the axial direction. Stage L3 is the fourth stage (the last stage) and is the largest (in the radial direction). It should be understood that four stages are shown as an example only, and each turbine may have more or less than four stages.

[0079] A plurality of stationary turbine blades or nozzles 112 (hereinafter referred to as “nozzles 112” or “nozzles 112”) may cooperate with a plurality of rotating turbine blades 114 (hereinafter referred to as “blades 114” or “blades 114”) to form each stage L0-L3 of the turbine 108 and define a portion of the working fluid path through the turbine 108. The blades 114 of each stage are formed by, for example, coupling them circumferentially to the rotor 110 ( Figure 1 ) is coupled to the rotor 110 ( Figure 1 That is, blades 114 are mechanically coupled to rotor 110 in a circumferentially spaced manner, for example, via rotor wheel 116. Stationary nozzle segment 115 includes a housing 118 mounted thereto and surrounding rotor 110 ( Figure 1 ) a plurality of nozzles 112 spaced circumferentially. It should be appreciated that the blades 114 are spaced circumferentially from the rotor 110 ( Figure 1 ) rotates together and is therefore subjected to centrifugal forces, while nozzle 112 is stationary.

[0080] refer to Figure 1 and Figure 2 In operation, air flows through the compressor 102, and the pressurized air is supplied to the combustor 104. Specifically, the pressurized air is supplied to the fuel nozzle section 106, which is integral with the combustor 104. The fuel nozzle section 106 is in fluid communication with the combustion zone 105. The fuel nozzle section 106 is also connected to a fuel source ( Figure 1The compressor 102 may also be rotatably coupled to the rotor 110. At least one end of the rotor 110 may extend axially away from the compressor 102 or the turbine 108 and may be attached to a load or machine (not shown), such as, but not limited to, a generator, a load compressor, and / or another turbine.

[0081] Figure 3 A perspective view of a (rotating) blade 114 of the type in which embodiments of the vibration damping system 120 of the present disclosure may be employed is shown. As will be described herein, Figure 4 and Figure 5 A schematic cross-sectional view of a blade 114 including a vibration damping system 120 is shown according to various embodiments of the present disclosure.

[0082] refer to Figure 3 Each blade 114 includes a body 128 having a base end 130, a tip end 132, and an airfoil 134 extending between the base end 130 and the tip end 132. Figure 3 As shown in FIG. 1 , the blade 114 includes a dovetail 140 at the base end 130 by which the blade 114 is attached to the rotor 110 ( Figure 1 ) of the rotor wheel 116 ( Figure 2 ). The base end 130 of the blade 114 may also include a shank 142 extending between the dovetail 140 and a platform 146. The platform 146 is disposed at the junction of the airfoil 134 and the shank 142 and defines a working fluid path through the turbine 108 ( Figure 2 ) is a portion of the inner boundary of a .

[0083] It will be appreciated that the airfoil 134 in the blade 114 is a moving part of the blade 114 that intercepts the flow of the working fluid and causes the rotor 110 ( Figure 1) rotation. It will be seen that the airfoil 134 of the blade 114 includes a concave pressure side (PS) outer sidewall 150 and a circumferentially or laterally opposed convex suction side (SS) outer sidewall 152 extending axially between opposed leading and trailing edges 154, 156, respectively. The sidewalls 150 and 152 also extend in a radial direction from the base end 130 (i.e., the platform 146 for the blade 114) to the tip end 132 (i.e., the tip end 158 for the blade 114). Note that in the example shown, although the blade 114 does not include a tip shroud, the teachings of the present disclosure are equally applicable to blades that include a tip shroud at the tip end 158. Figure 3 The blades 114 shown in FIG. 1 are merely exemplary, and the teachings of the present disclosure may be applicable to any type of blades.

[0084] During operation of the turbine, the blades 114 can be excited into vibration by a number of different forcing functions. For example, changes in the working fluid temperature, pressure, and / or density can excite vibrations throughout the rotor assembly, particularly within the airfoils and / or tips of the blades 114. Gases exiting the turbine and / or compressor section upstream in a periodic or "pulsating" manner can also excite undesirable vibrations. The present disclosure is intended to reduce vibrations of the rotating turbine blades 114 without significantly changing the blade design.

[0085] Figure 4 and Figure 5 Schematic cross-sectional views of a blade 114 including a vibration damping system 120 according to an embodiment of the present disclosure are each shown. The vibration damping system 120 for the blade 114 may include a body opening 160 that extends through the body 128 at least partially between the tip end 132 and the base end 130 and through the airfoil 134. The body opening 160 may extend a portion of the distance between the base end 130 and the tip end 132, or it may extend through one or more of the base end 130 or the tip end 132. The body opening 160 may be defined in any portion of any structure of the body 128. In the case where the body 128 includes, for example, an internal dividing wall (not shown) for defining a cooling circuit therein, the body opening 160 may be defined as an inner cavity in the dividing wall in the body 128. The body opening 160 generally extends radially in the body 128. However, the body opening 160 may be angled relative to the radial extent of the body 128 and may be curved. The body opening 160 has an inner surface 162.

[0086] like Figure 4 As shown in FIG. 1 , the body opening 160 may begin at the base end 130 of the blade 114 or as shown in FIG. Figure 5 As shown in FIG. 1 , the main body opening may begin at the tip end 132 of the blade 114. More specifically, as shown in FIG. Figure 4 As shown in FIG. 1 , the body opening 160 may open in the base end 130 and terminate in the tip end 132, or as shown in FIG. Figure 5 As shown in , the body opening may open in the tip end 132 and terminate in the base end 130. The open end may facilitate assembly of the vibration damping system 120 in the blade 114 and may allow the system to be retrofitted into existing blades. Figure 4 As shown in FIG. 1 , in the case where the main body opening 160 extends through the base end 130 , a closing member 164 for closing the main body opening 160 may be provided. Figure 5 As shown in FIG. 1 , where the body opening 160 extends through the tip end 132 , a closure member 166 may be provided for the body opening 160 . In addition to closing the body opening 160 , the closure members 164 , 166 also prevent the vibration damping system 120 from being removed from the body opening 160 .

[0087] The vibration damping system 120 for the blade 114 may include a plurality of damper elements 170 ( Figures 6 to 12 )、270( Figures 13 to 18B ). A damper element for the vibration attenuation system 120 is positioned in a body opening 160 in the rotating blades 114 of the turbine 108. According to embodiments of the present disclosure, the damper element can take a variety of forms. In general, the damper element includes: a base member having an axially fixed position within the body opening; and a spring-suspended support member having a spring fixedly coupled to the base member at a first end of the spring and a support member coupled to a second end of the spring. When the spring is in an elastically extended state under the influence of centrifugal forces caused by the rotation of the rotating blades at a speed greater than a predefined rotational speed, the support member frictionally engages the first support surface to attenuate vibrations, thereby forming the mentioned first friction-based vibration attenuation interface. As will be further described, the first friction-based vibration attenuation interface is subjected to the reduced influence of the centrifugal forces formed by the rotating blades by using the spring to provide a reaction force reduction.

[0088] Figure 6 shows a cross-sectional view of a damper element 170 according to certain embodiments of the present disclosure, and Figure 7 A perspective view of the damper element is shown. Fig. 8A A cross-sectional view of three stacked damper elements 170 in a first position in the body opening 160 of the blade 114 is shown, and Figure 8B A cross-sectional view of three stacked damper elements 170 is shown in a second position. Any number of damper elements 170 may be used in the vibration damping system 120 according to embodiments of the present disclosure.

[0089] like Figure 6 , Figure 7 and FIG. 8A to FIG. 8B As shown in FIG. 1 , each damper element 170 may include a base member 172 having an axially fixed position ( FIG. 8A to FIG. 8B ). The base member 172 can have a cross-sectional shape configured to match or interface with the cross-sectional shape of the body opening 160, such as a circular or other shape. As will be further described, except that the base member 172 of the radially outermost damper element 170X (as the end of a single damper element or a stack of damper elements) engages with the end surface 210 of the body opening 160, the base member 172 does not engage the inner surface 162 of the body opening 160. In this way, the base member 172 is axially fixed in place in the body opening 160 by the common interaction of the base members over the length of the body opening 160 and under the influence of centrifugal force. The base member 172 may include a slender body 173 ( Figure 6 ), the elongated body having its first end surface 176A (only Figure 6 to Figure 7 ), the first end surface is configured to be adjacent to the second end surface 176B of the base member 172 of the damper element 170 (only Figure 6 That is, the base member 172 may include a mating end surface 176 ( FIG. 8A to FIG. 8B ), the mating end surface is configured to fixedly position the base member 172 in the body opening 160 in a stacked arrangement. The mating end surface 176 can also provide a friction-based vibration damping interface that is friction-based vibration damping interface under centrifugal force CF ( Figure 8B ) under the full influence of the vibration damping therebetween, thereby forming the mentioned second friction-based vibration damping interface. In the example shown, the mating end surfaces 176 are mating curved concave and convex surfaces, such as domes. Other shapes that allow relative frictional movement are also possible, such as but not limited to: conical concave / convex, square concave / convex, etc. The second friction-based vibration damping can occur at each set of mating surfaces 176 in the stacked damper element 170.

[0090] As noted, the base member 172 is axially fixed in place within the body opening 160 by the combined interaction of the base members over the length of the body opening 160 and the base member of the radially outermost damper element 170X engaging the end surface 210 of the body opening 160. Figure 8BAs shown in FIG. 1 , the base member 172 of the radially outermost damper element 170X may also have a mating end surface 176A that mates with a mating surface 208 in the end surface 210 of the body opening 160. The mating end surfaces 176A, 208 may provide the endmost interface of a second friction-based vibration damping interface that is provided under the centrifugal force CF ( Figure 8B ) to dampen vibrations therebetween under the full influence of the stacked damper element 170. In the example shown, the mating end surfaces 176A, 208 are also mating curved concave and convex surfaces, such as domes. As mentioned herein, other shapes are also possible. It should also be noted that the mating surfaces 176, 208 do not need to be the same at every interface along the stacked damper element 170.

[0091] The damper element 170 also includes a spring-suspended support member 174 ( Figure 6 to Figure 7 ).exist Figure 6 , Figure 7 , FIG. 8A to FIG. 8B , a spring-suspended support member 174 includes a coil spring 180 fixedly coupled to a base member 172 at a center 194 of the coil spring 180, and a support member 186 coupled to a first side 198 of the coil spring 180 at a periphery (i.e., relative to the center 194) of the support member. The support member 186 may include any element capable of frictionally engaging a first support surface 190 to attenuate vibrations. As will be described, the location of the first support surface 190 may vary depending on the particular damper element 170. In Figure 6 , Figure 7 , FIG. 8A to FIG. 8B In the embodiment of the present invention, the coil spring 180 includes any form of coil spring, which is also alternatively referred to as, for example, a Belleville washer, a Belleville spring, a cup spring washer, a conical coil spring, a conical spring washer, etc. Although shown in a planar initial configuration, the coil spring 180 can also have any truncated cone arrangement and other shapes. The coil spring 180 can have any form that can provide a desired spring action or spring constant.

[0092] The coil spring 180 has a center 194 coupled to the base member 172 and a first side 198 ( Figure 6) periphery 196. The coil spring 180 also includes a second side 200 opposite the first side 198. The center 194 of the coil spring 180 can be fixedly coupled to the elongated body 173 of the base member 172 in any manner now known or later developed. For example, where the center 194 includes an opening, the center 194 of the coil spring 180 can be welded or brazed to the base member 172. Alternatively, the coil spring 180 and the base member 172 can be additionally manufactured as an integral component along with the support member 186. The support member 186 is coupled to the first side 198 of the coil spring 180 and extends radially distally from the first side 198 of the coil spring 180, i.e., relative to the turbine axis. In certain embodiments, as Figure 6 , Figure 7 , FIG. 8A to FIG. 8B As shown in FIG. 1 , the support member 186 may extend radially inward, ie, from the first side 198 of the coil spring 180 toward the base end 130 of the blade 114 .

[0093] Fig. 9 174, wherein the support member 186 also extends radially distally from the first side 198 of the coil spring 180, but extends radially outwardly from the first side 198 of the coil spring 180, i.e., toward the tip end 132 ( Figures 4 to 5 ) extension. Fig. 9 In, with Figures 6 to 8B In comparison, the positions of the first side 198 and the second side 200 are switched.) The coil spring 180 may have a different thickness than the support member 186. The thickness of the coil spring 180 may vary within its radial extent to provide any desired spring action or spring constant.

[0094] In certain embodiments, the damper elements 170 are stacked together in the body opening 160. Any number of damper elements 170 may be stacked in the body opening 160. FIG. 8A to FIG. 8B Three damper elements 170 are shown stacked in the body opening 160 . Fig. 8AThe damper element 170 is shown in a position where the blade 114 is not rotating or alternatively is rotating at a rotational speed ω (omega), which is lower than a predefined rotational speed at which the damper element 170 operates. In this first position, the coil spring 180 is in a not fully extended state, and there is a gap G between the first bearing surface 190 (in the form of the second side 200 of the coil spring 180) and the end surface 204 of the support member 186. The "not fully extended state" of the coil spring 180 can be a relaxed state where the coil spring 180 is not extended (as occurs when the rotating blade 114 is not rotating) or a partially extended state where the coil spring 180 is partially extended (as occurs when the rotating blade 114 has a sufficient rotational speed to generate a centrifugal force CF to cause the coil spring 180 to partially extend but not enough to cause the support member 186 to frictionally engage the first bearing surface 190).

[0095] In contrast, Figure 8B The damper element 170 is shown in a second position in which the coil spring 180 is in an elastically stretched state under the influence of the centrifugal force CF caused by the rotating blade 114 rotating at a speed higher than a predefined rotation speed. In this position, the coil spring 180 is at its outer periphery 196 (towards the tip end 132 ( Figures 4 to 5 ) elastically stretches radially outward, so that the gap G ( Fig. 8A ) disappears, and causes the support member 186 to frictionally engage the first support surface 190 to dampen vibrations. As shown, for stacked damper elements 170 other than the radially outermost damper element 170X, the first support surface 190 may be a second side 200 of the coil spring 180 adjacent to the damper element. That is, the first support surface 190 includes a second side 200 of the coil spring 180 opposite the first side 198. Here, the end surface 204 of the support member 186 frictionally engages the second side 200 of the coil spring 180 adjacent to the damper element 170 to dampen vibrations. For the radially outermost damper element 170X, the second side 200 of its coil spring 180 frictionally engages the first support surface 190, which is a portion of the end surface 210 (i.e., the radially outer end surface 210) of the body opening 160. In view of the foregoing, it will be appreciated that the first bearing surface 190 may be located on one of the following: the second side 200 of the coil spring 180; the first side 198; and / or the end surface 210 of the body opening 160 in the rotating blade 114. Although the "elastically extended state" indicates that the coil spring 180 has been fully extended so that the support member 186 frictionally engages the first bearing surface 190, the coil spring may not be fully extended because the travel distance of the support member 186 is limited by the first bearing surface 190.

[0096] In certain embodiments, the base member 172, the coil spring 180, and the support member 186 are additively manufactured and integrally coupled. In other embodiments, the base member 172, the coil spring 180, and the support member 186 can be formed separately from any material (metal, ceramic, etc.) that imparts the desired stiffness characteristics. These members can be fixedly coupled using any now known or later developed process (e.g., welding, brazing, fasteners, etc.).

[0097] The spring constant of the coil spring 180 and the total mass of the support member 186 and the coil spring 180 are configured to allow the coil spring 180 to disengage from the first bearing surface 190 in response to the centrifugal force CF caused by the rotation of the rotating blade 114 at a speed higher than the predefined rotation speed. Fig. 8A ) is moved to a position where it frictionally engages with the first bearing surface 190 ( Figure 8B ). Fig.10 A schematic diagram illustrating the forces involved in the operation of the damper element 170 is shown. For a given rotational speed ω of the rotating blade 114, a certain centrifugal force CF, i.e., the gravitational equivalent (g-force), is generated on the rotating blade 114. More specifically, the centrifugal force CF is equal to the damper mass m d times the radius (the approximate position of the damper element 170 mass relative to the turbine axis) times the square of the rotational speed ω, ie CF = m d rω 2 The damper element 170 also exerts a reaction force R on the end surface 210 of the main body opening 160, which is equal to the centrifugal force CF, that is, R=CF. When the rotating blade 114 rotates at the rotation speed ω, the rotating blade also forms a lateral vibration force VF. The vibration force VF can be simplified to be equal to the damper mass m d Multiply by the simple harmonic oscillation sine function Right now The friction force FF that resists the vibration attenuation of the components of the damper element 170 is equal to the reaction force R multiplied by the friction coefficient μ (mu) of the relevant friction engagement surface (e.g. 190 or 198, 210), that is, FF = μR or FF = μCF. If the damper element 170 has friction vibration attenuation that occurs between its surfaces (e.g., the first bearing surface 190 and the bearing member 186), these surfaces need to slide back and forth to attenuate the vibration. In order for this to occur, the vibration force VF must be greater than the friction force FF, that is, VF>FF. Therefore, the vibration force VF must be greater than the product of the centrifugal force CF and the friction coefficient μ of the surface, that is, VF>μCF.

[0098] According to an embodiment of the present disclosure, the coil spring 180 in the damper element 170 applies a reaction force Kx that constructively reduces the centrifugal force CF (and the reaction force R) to reduce the amount of vibration force VF required to begin vibration attenuation. That is, the coil spring 180 reduces the force between the vibration attenuation surfaces (e.g., the first bearing surface 190 and the support member 186) to reduce the amount of vibration force VF required to begin vibration attenuation. The damper element 170 can be sized to operate at different centrifugal forces CF, radial positions, vibration frequencies, and rotational speeds, among other factors.

[0099] exist FIG. 8A to FIG. 8B , the damper element 170 is illustrated as a separate entity stacked together, for example, by the mating surfaces 176 of the base member 172. FIG. 11A to FIG. 11B In other embodiments shown in FIG. 1 , the base member 172 may be a one-piece base member having a one-piece elongated body 214 (rather than a plurality of elongated bodies 173). The coil spring 180 is fixedly coupled to the elongated body 214. In this case, the plurality of damper elements 170 (i.e., the base member 172) are integral with one another. Although FIG. 11A to FIG. 11B The support member 186 is shown extending radially inwardly relative to the corresponding coil spring 180. Figure 6 implementation plan, but FIG. 11A to FIG. 11B The implementation scheme is equally applicable to Fig. 9 The teaching content in which the support member 186 extends radially outward relative to the corresponding disc spring 180.

[0100] exist Figure 6 , Figure 7 , FIG. 8A to FIG. 8B , Fig. 9 and FIG. 11A to FIG. 11B , as mentioned, the coil spring 180 is fixedly coupled to the base member 172 or the base member 272, such as by fusion welding or via integral additive manufacturing. Fig.12 A cross-sectional view of another embodiment of a coil spring 180 that may, but need not, be fixedly coupled to a base member 172, 214 is shown. Fig.12 194, the base member 172 also includes a positioning collar 216 that can be arranged concentrically with its elongated body 173. In this example, a single base member 172 with an integral elongated body 214 is illustrated. Thus, the positioning collar 216 can axially position the corresponding coil spring 180 relative to the base member 172, while the coil spring 180 is not fixedly coupled to the base member 172. The positioning collar 216 can be a tubular member that slides onto the base member 172, or can be integrally formed with the base member 172. In any case, the end 218 of the positioning collar 216 can abut the second side 200 of the coil spring 180 adjacent the center 194 to position the coil spring 180 and provide a surface on which the coil spring 180 can elastically expand.

[0101] Figures 13 to 17B A vibration damping system 220 including a different spring-suspended support member 274 is shown according to other embodiments of the present disclosure. Fig.13 and Fig.14 Each shows a schematic cross-sectional view of a blade 114 including a vibration damping system 220 according to an embodiment of the present disclosure. The vibration damping system 220 for the blade 114 may include a body opening 160 extending through the body 128, as previously described herein. Fig.13 As shown in FIG. 1 , the body opening 160 may begin at the base end 130 of the blade 114 or as shown in FIG. Fig.14 As shown in FIG. 1 , the main body opening may begin at the tip end 132 of the blade 114. Fig.13 As shown in FIG. 1 , in the case where the main body opening 160 extends through the base end 130 , a closing member 164 for closing the main body opening 160 may be provided. Fig.14 As shown in FIG. 1 , where the body opening 160 extends through the tip end 132 , a closure member 166 may be provided for the body opening 160 . In addition to closing the body opening 160 , the closure members 164 , 166 also prevent the vibration damping system 120 from being removed from the body opening 160 .

[0102] The vibration damping system 220 for the blade 114 may include a plurality of damper elements 270. The damper elements 270 for the vibration damping system 220 are positioned at the turbine 90 ( Figure 1 ) in the main body opening 160 in the rotating blade 114. Fig.15 shows a side view of a damper element 270 according to an embodiment of the present disclosure, and Fig.16 A perspective view of the damper element is shown. Fig.17A shows a side view of two stacked damper elements 270 in a first position in the body opening 160 of the blade 114 according to an embodiment of the present disclosure, and Fig. 17B 1 shows a side view of two stacked damper elements 170 in a second position according to an embodiment of the present disclosure. Fig.15 and Fig.16 As shown in FIG. 1 , each damper element 270 may include a base member 272 having an axially fixed position ( FIG. 17A to FIG. 17B The base member 272 may have a cross-sectional shape configured to match the cross-sectional shape of the body opening 160, such as a circular or other shape. The base member 272 does not engage the body opening 160. The base member 272 may include a first side 294 and a second side 296.

[0103] The damper element 270 also includes a spring-suspended support member 274. Fig.15 , Fig.16 , FIG. 17A to FIG. 17B , a spring-suspended support member 274 includes a spring 280 fixedly coupled to a base member 272 at a first end 282 of the spring 280 and a support member 286 coupled to a second end 288 of the spring 280. The support member 286 may include any element capable of frictionally engaging a first support surface 290 to attenuate vibrations. In the example shown, the support member 286 includes a circular plate having a surface 292. As will be described, the first support surface 290 that is frictionally engaged with the support member 286 may vary depending on the position of the particular damper element 270 in the stack.

[0104] exist Fig.15 , Fig.16 , FIG. 17A to FIG. 17B and FIG. 18A to FIG. 18B , the spring 280 includes a plurality of partial helical coils 300 extending from a first side 294 of a base member 272 to a support member 286. Each partial helical coil 300 includes a first end 302 coupled to the first side 294 of the base member 272 at a first circumferential position relative to the central axis CA of the base member 272, and a second end 304 coupled to the support member 286 at a second circumferential position different from the first circumferential position relative to the central axis CA of the base member 272. In this way, each coil 300 provides a partial helical coil because, although they extend in a helical manner, they extend only a portion of 360° around the central axis CA of the base member 286. The first end 302 of each partial helical coil 300 can be coupled to the first side 294 of the base member 272 at a perpendicular angle, and the second end 304 of each partial helical coil 300 can be coupled to the support member 286 at a perpendicular angle. Other angles are also possible. Any number of helical coils 300 having any cross-sectional shape and / or size can be used to form a desired spring constant for the spring 280. The spring 280 allows the support member 286 to move radially relative to the turbine axis within the body opening 160 in the rotating blade 114 to counteract the centrifugal force CF ( Fig. 17B , 18B ). Although a specific partial coil spring 280 has been disclosed herein, it should be understood that other forms of coil springs may also be provided.

[0105] The damper element 270 may also include a positioning member 310 having a first end 312 and a second end 314. The positioning member 310 positions the damper elements 270 relative to each other in the stack and the stack relative to the body opening 160. For example, the damper elements 270 may be positioned relative to each other and the stack as a whole relative to the body opening 160 by positioning the end surfaces 316 ( FIG. 17A to FIG. 18B) sequential positioning, the positioning member 310 also fixes the position of the damper element 270 relative to the main body opening 160. (Note that FIG. 17A to FIG. 17B and FIG. 18A to FIG. 18B Shown based on Fig.13 The end surface 316 in the tip end 132 of the embodiment, wherein the closure member 164 (not shown) is located in the base end 130 of the rotating blade 114. Fig.14 , in the case where a closure member 166 is used in the tip end 132 of the rotating blade 114, at least a portion of the end surface 316 of the body opening 160 can be provided by the closure member 166.) The positioning member 310 is coupled to the first side 294 of the base member 272 at the first end 312 of the positioning member 310 and extends from the first side. The positioning member 310 extends adjacent to the spring 280. More specifically, the positioning member 310 can extend within the spring 280 and be surrounded by the spring.

[0106] like FIG. 17A to FIG. 17B As shown in FIG. 1 , for all damper elements except the radially outermost damper element 270X, the first bearing surface 290 frictionally engaged by the bearing member 286 may be the second side 296 of the base member 272. This first friction-based vibration damping interface occurs under the influence of a portion / reduction of the centrifugal force CF of the rotating blade 114 due to the reaction force Kx ( Fig.10 ) is reduced. In addition, for all damper elements except the radially outermost damper element 270X, the second end 314 of the positioning member 310 is configured to frictionally engage with a second bearing surface 320 on the second side 296 of the base member 272 to attenuate vibration. This second friction-based vibration attenuation interface occurs under the entire centrifugal force CF of the rotating blade 114 transmitted through the stacked positioning member 310. The second bearing surface 320 can be any surface on the second side 296 of the base member 272 that is configured to cooperate with the second end 314 of the positioning member 310. In the example shown, the second bearing surface 320 includes a concave surface that is configured to cooperate with a convex surface of the second end 314 of the positioning member 310, such as a dome shape. As mentioned with respect to the previous embodiment, other mating surface shapes are also possible.

[0107] For the radially outermost damper element 270X, the first bearing surface 290 may be any portion of the end surface 316 of the body opening 160 that is frictionally engaged by the support member 286 (i.e., the surface 292 of the support member 286). Similarly, for the radially outermost damper element 270X, the second bearing surface 320 that is frictionally engaged by the second end 314 of the positioning member 310 may be a portion of the end surface 316 of the body opening 160 that has, for example, a concave surface to mate with the second end 314 of the positioning member 310 of the radially outermost damper element 270X. As mentioned with respect to the previous embodiment, other mating surface shapes are also possible.

[0108] like Fig.17A and Fig.18A , the positioning member 310 has a length configured to axially fix the corresponding base member 272 in place within the body opening 160. The spring 280 (in conjunction with the positioning member 310) positions the support member 286 in one of two positions determined by the rotational speed of the rotating blade 114. In the first position, the spring 280 positions the support member 286 to be at a distance (i.e., gap G) from the first support surface 290, wherein the rotating blade 114 rotates at a speed lower than the predefined rotational speed and the spring 280 is in a not fully extended state. The "not fully extended state" of the spring 280 can be a relaxed state in which the spring 280 is not extended (as occurs when the rotating blade 114 is not rotating) or a partially extended state in which the spring 280 is partially extended (as occurs when the rotating blade 114 has a sufficient rotational speed to form a centrifugal force CF so that the spring 280 is partially extended but not enough to cause the support member 286 to frictionally engage the first support surface 290).

[0109] In this position, the support member 286 (its surface 292) does not engage the first support surface 290 when the rotating blade 114 is not rotating or is not rotating at a rotational speed higher than a predefined rotational speed, which is sufficient to generate a centrifugal force CF sufficient to guide the support member 286 to frictionally engage with the first support surface 290. In this case, the spring 280 is in an unextended state, so that there is a gap G between the support member 286 and the first support surface 290, that is, the gap exists on the second side 296 adjacent to the base member 272 or on the end surface 316 of the main body opening 160. However, in this case, the second end 314 of the positioning member 310 is still configured to frictionally engage with the second support surface 320 on the second side 296 of the base member 272 or the inner surface 162 of the main body opening 160 to dampen vibration.

[0110] In contrast, in (such as Fig. 17B and Fig.18BIn the second position (shown in FIG. 1 ), the spring 280 positions the support member 286 to frictionally engage the first support surface 290 to dampen vibrations, wherein the rotating blade 114 rotates at a speed greater than the predefined rotational speed and the spring 280 is in an elastically stretched state. In this case, once the rotating blade 114 has a rotational speed greater than the predefined rotational speed, sufficient centrifugal force CF is generated to force the base member 286 to frictionally engage the first support surface 290 to dampen vibrations. Fig.10 As described, the spring 280 reduces the amount of rotational speed and associated centrifugal force CF required to achieve frictional engagement and vibration damping through the interface between the support member 286 and the first support surface 290. The "elastically extended state" indicates that the spring 280 has been fully extended to allow the support member 286 to frictionally engage the first support surface 290, but the spring may not be fully extended because the travel distance of the support member 286 is limited by the first support surface 290. In addition, in this case, the second end 314 of the positioning member 310 is still configured to frictionally engage with the second support surface 320 on the second side 296 of the base member 272 or the end surface 316 of the body opening 160 to dampen vibration. However, if the centrifugal force CF is sufficient to prevent operation of this second friction-based vibration damping interface (i.e., by applying a force that prevents frictional movement), the first friction-based vibration damping interface between the support member 286 and the first support surface 290 remains operational.

[0111] The damper elements 270 are stacked together in the body opening 160 . FIG. 17A to FIG. 17B and 18A to Fig.18B Two damper elements 270 are shown stacked in the body opening 160. Any number of damper elements 270 may be stacked in the body opening 160. Fig.17A and Fig.18A The damper element 270 is shown in a (first) position in which the blade 114 is not rotating or is rotating at a rotational speed ω, which is lower than a predefined rotational speed at which the damper element 270 operates. In this position, the spring 280 (helical coil 300) is not fully extended and there is a gap G between the support member 286 and the first support surface 290 (e.g., the second side 296 of the base member 272 or the end surface 316 of the body opening 160).

[0112] In contrast, Fig. 17B and Fig.18BThe damper element 270 is shown in a (second) position in which the spring 280 (helical coil 300) is in an elastically extended state under the influence of the centrifugal force CF caused by the rotation of the rotating blade 114 at a speed higher than the predefined rotational speed. In this position, the spring 280 is radially extended outward, so that the gap G disappears and the support member 286 frictionally engages the corresponding first support surface 290 to dampen the vibration. As shown, for the stacked damper elements 270 other than the radially outermost damper element 270X, the first support surface 290 can be a second side 296 of the base member 272 adjacent to the damper element. That is, the first support surface 290 includes a second side 296 of the base member 272 opposite to the first side 294. Here, the surface 292 of the support member 286 frictionally engages the second side 296 of the base member 272 adjacent to the damper element 270 to dampen the vibration. For the radially outermost damper element 270X, the surface 292 of the support member 286 frictionally engages the first support surface 290, which is a portion of the end surface 316 of the body opening 160. The positioning member 310 of the radially outermost damper element 270X may also have its second end 314 engaged with a mating second support surface 320 in the end surface 316 of the body opening 160 to dampen vibrations.

[0113] The spring constant of the spring 280 (helical coil 300) and the total mass of the support member 286 and the spring 280 are configured to allow the spring 280 to disengage from the first support surface 290 in response to the centrifugal force CF caused by the rotation of the rotating blade 114 at a speed higher than the predefined rotation speed. Fig.17A , Fig.18A ) moves to a position where it frictionally engages with the first bearing surface 290 ( Fig. 17B , Fig.18B ). As previously mentioned with respect to Fig.10 As explained, for a given rotating blade 114, a certain centrifugal force CF, i.e., a gravity equivalent (g-force), is formed on the rotating blade 114 for a rotational speed ω. When the rotating blade 114 rotates at the rotational speed ω, the rotating blade also forms a lateral vibration force VF. The friction force FF that resists the vibration attenuation of the components of the damper element 270 is equal to the reaction force R multiplied by the friction coefficient μ of the relevant friction engagement surface (e.g., 190 and 296 or 316), i.e., FF=μR or FF=μCF. If the damper element 270 has friction vibration attenuation that occurs between its surfaces (e.g., the first bearing surface 290 and the supporting member 286), the surface needs to slide back and forth to attenuate the vibration. In order for this to occur, the vibration force VF must be greater than the friction force FF, i.e., VF>FF. Therefore, the vibration force VF must be greater than the product of the centrifugal force CF and the friction coefficient μ of the surface, i.e., VF>μCF.

[0114] According to an embodiment of the present disclosure, the spring 280 in the damper element 270 forms a reaction force Kx that constructively reduces the centrifugal force CF (and the reaction force R) to reduce the amount of vibration force VF required to begin vibration attenuation. That is, the spring 280 reduces the force between the vibration attenuation surfaces (e.g., the first bearing surface 290 and the support member 286) to reduce the amount of vibration force VF required to begin vibration attenuation. The damper element 270 can be sized to operate at different centrifugal forces CF, radial positions, vibration frequencies, and rotational speeds, among other factors.

[0115] In certain embodiments, the base member 272, the spring 280, and the support member 286 (and the positioning member 310) are additively manufactured and integrally connected. In other embodiments, the base member 272, the spring 280, and the support member 286 can be formed separately and fixedly connected together using any now known or later developed process (e.g., welding, brazing, fasteners, etc.).

[0116] Any number of damper elements 170, 270 may be used in the vibration damping system 120 depending on, among other factors, the length of the blade 114, the desired vibration damping, and / or the available space. As described, the endmost damper element in the stack of damper elements 170X, 270X may abut the end surface 210, 316 of the body opening 160, see e.g. Fig. 11B , Fig. 17B and Fig.18B Alternatively, if Figure 5 and Fig.14 As shown in FIG, a portion of the end surface 210 , 316 may be provided by the closure member 166 .

[0117] In addition to the two forms of vibration damping previously described, vibration damping may also occur through frictional engagement of the outer dimensions of components of the damper element 170, 270 with the inner dimensions of the inner surface 162 of the body opening 160 in the blade 114. For example, Fig.11A , Fig. 11B In another example, the outer surface of the support member 186 and / or the coil spring 180 can frictionally engage the inner surface 162 of the body opening 160 to dampen vibrations. FIG. 17A to FIG. 17B In one embodiment, the outer surfaces of the support member 286, the spring 280, and / or the base member 272 can frictionally engage the inner surface 162 of the body opening 160 to dampen vibrations.

[0118] As mentioned herein, the damper elements 170, 270 can be manufactured in any now known or later developed manner. For example, the damper elements 170, 270 can be cast, and the components can be assembled, for example, by welding or otherwise fastening the components together. In other embodiments, the damper elements 170, 270 can be additively manufactured. Any form of additive manufacturing suitable for the materials used can be used, such as but not limited to direct metal laser melting (DMLM).

[0119] Embodiments of the present disclosure provide various technical and commercial advantages, examples of which are discussed herein. The vibration damping system 120 reduces blade vibrations using a simple arrangement and does not add much additional mass to the blade 114. The vibration damping system 120 does not increase the centrifugal force on the tip end 132 of the blade 114 or require a change in the configuration of the blade 114. One or more damper elements 170, 270 may be used. The damper element 170, 270 includes a first friction-based vibration damping interface that damps vibrations when the blade 114 is subjected to the full centrifugal force of the normal rotational speed of the blade 114. Advantageously, the one or more damper elements 170, 270 may also provide a second friction-based vibration damping interface, the frictional engagement of which damps vibrations when the blade 114 is subjected to a constructively reduced centrifugal force (e.g., at a reduced rotational speed). This latter vibration damping may occur at a rotational speed that is less than the full load rotational speed of the turbine. For example, vibration damping can occur during acceleration of the rotating blades (e.g., early in the turbine startup process) and during deceleration of the rotating blades (e.g., during the turbine shutdown process). This latter vibration damping may occur despite the fact that other vibration damping interfaces are ineffective because centrifugal forces render them ineffective.

[0120] As used throughout the specification and claims, approximate language can be used to modify any quantitative representation that can be permitted to vary without resulting in a change in the basic function to which it is associated. Therefore, values ​​modified by one or more terms (such as "about", "approximately" and "substantially") are not limited to the precise values ​​specified. In at least some cases, approximate language can correspond to the precision of the instrument used to measure the value. Here and throughout the specification and claims, range limitations can be combined and / or interchanged; unless the context or language indicates otherwise, these ranges are identified and include all subranges contained therein. "Approximately" applied to a particular value of a range applies to both end values ​​and may indicate + / -10% of the value unless otherwise dependent on the precision of the instrument measuring the value.

[0121] The corresponding structures, materials, actions and equivalents of all means or steps plus function elements in the following claims are intended to include any structure, material or action for performing functions in conjunction with other claimed elements specifically claimed. A description of the present disclosure has been given for the purpose of illustration and description, but it is not intended to be exhaustive or limit the present disclosure to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and essence of the present disclosure. Embodiments have been selected and described in order to best explain the principles of the present disclosure and its practical application, and to enable other persons of ordinary skill in the art to understand the various embodiments of the present disclosure and various modifications as are suitable for the intended specific use.

Claims

1. A damper element (270) for a vibration damping system (220) in a body opening (160) in a rotating blade (114) in a turbine (108), the damper element (270) comprising: a base member (272) having an axially fixed position within the body opening (160); and a spring-suspended support member (274) having the spring (280) fixedly coupled to the base member (272) at a first end (282) of the spring (280) and a support member (286) coupled to a second end (288) of the spring (280), Wherein, when the spring (280) is in an elastically extended state under the influence of centrifugal force caused by the rotation of the rotating blade (114) at a speed higher than a predefined rotation speed, the support member (286) frictionally engages the first support surface (290) to dampen vibration.

2. The damper element (270) of claim 1, wherein a spring constant of the spring (280) and a combined mass of the support member (286) and the spring (280) are configured to allow the support member (286) to move from a disengaged position with the first support surface (290) to a frictional engagement with the first support surface (290) in response to the centrifugal force caused by the rotation of the rotating blade (114) at a speed greater than the predefined rotational speed.

3. The damper element (270) of claim 1, wherein the base member (272) has a first side (294) and a second side (296), and the spring (280) includes a plurality of partial helical coils (300) extending from the first side (294) of the base member (272) to the support member (286).

4. A damper element (270) according to claim 3, wherein each partial helical coil (300) includes a first end (302) connected to the first side (294) of the base member (272) at a first circumferential position relative to the central axis of the base member (272), and a second end (304) connected to the support member (286) at a second circumferential position different from the first circumferential position relative to the central axis of the base member (272).

5. The damper element (270) of claim 4, wherein the first end (302) of each partial helical coil (300) is coupled to the first side (294) of the base member (272) at a perpendicular angle, and the second end (304) of each partial helical coil (300) is coupled to the support member (286) at a perpendicular angle.

6. The damper element (270) of claim 3, further comprising a positioning member (310) having a first end (312) and a second end (314), the positioning member (310) being coupled to the first side (294) of the base member (272) at the first end (312) of the positioning member (310) and extending from the first side, the positioning member (310) extending adjacent to the spring (280).

7. The damper element (270) of claim 6, wherein the first bearing surface (290) is located on the second side (296) of the base member (272), and wherein the second end (314) of the positioning member (310) is configured to frictionally engage with a second bearing surface (320) on the second side (296) of the base member (272) to attenuate vibrations.

8. The damper element (270) of claim 6, wherein the positioning member (310) secures the base member (272) axially in position within the body opening (160), and the spring (280) positions the support member (286) such that: being at a distance from the first bearing surface (290), wherein the rotating blade (114) rotates at a speed lower than the predefined rotation speed and the spring (280) is in a non-fully extended state; and The first bearing surface (290) is frictionally engaged to damp vibrations, wherein the rotating blade (114) rotates above the predefined rotational speed and the spring (280) is in a resiliently extended state.

9. The damper element (270) of claim 1, wherein the first bearing surface (290) is located on one of: a side of the base member (272) adjacent to the damper element (270) and an end surface (210) of the body opening (160) in the rotating blade (114).

10. The damper element (270) according to claim 1, wherein the base member (272), the spring (280), and the support member (286) are additively manufactured and integrally coupled.

11. A vibration damping system (220) for a rotating blade (114), the vibration damping system (220) comprising: A plurality of stacked damper elements (270) for positioning in a body opening (160) defined in the rotating blade (114), each damper element (270) comprising: a base member (272) having an axially fixed position within the body opening (160); and a spring-suspended support member (274) having the spring (280) fixedly coupled to the base member (272) at a first end (282) of the spring (280) and a support member (286) coupled to a second end (288) of the spring (280), Wherein, when the spring (280) is in an elastically extended state under the influence of centrifugal force caused by the rotation of the rotating blade (114) at a speed higher than a predefined rotation speed, the support member (286) frictionally engages the first support surface (290) to dampen vibration.

12. The vibration damping system (220) of claim 11, wherein a spring constant of the spring (280) and a combined mass of the support member (286) and the spring (280) are configured to allow the support member (286) to move from a disengaged position from the first support surface (290) to a frictional engagement with the first support surface (290) in response to the centrifugal force caused by the rotation of the rotating blade (114) at a speed greater than the predefined rotational speed.

13. The vibration attenuation system (220) of claim 11, wherein the base member (272) has a first side (294) and a second side (296), and the spring (280) includes a plurality of partial helical coils (300) extending from the first side (294) of the base member (272) to the support member (286).

14. The vibration attenuation system (220) of claim 13, wherein each partial helical coil (300) includes a first end (302) coupled to the first side (294) of the base member (272) at a first circumferential position relative to a central axis of the base member (272), and a second end (304) coupled to the support member (286) at a second circumferential position relative to the central axis of the base member (272) that is different from the first circumferential position.

15. The vibration attenuation system (220) of claim 14, wherein the first end (302) of each partial helical coil (300) is coupled to the first side (294) of the base member (272) at a perpendicular angle, and the second end (304) of each partial helical coil (300) is coupled to the support member (286) at a perpendicular angle.

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