Rotor blade damping structure

Abstract

The present invention is titled Rotor Blade Damping Structure. The present invention provides a rotor blade assembly that includes a first rotor blade (48) and a second rotor blade (50) positioned adjacent to each other. The first rotor blade (48) and the second rotor blade (50) each include a platform (66) and a fin (52) that extends radially outward from a root (64) coupled to the platform (66) to a tip (68). The fin (52) includes a partial span shroud. The partial span shroud (72, 73) extends from the fin (52) and is disposed between the root (64) and the tip (68). The partial span shroud (72, 73) includes a pressure side portion (76) that extends from a pressure side surface (54) and a suction side portion (74) that extends from a suction side surface (56). A damper (100) contacts both the partial span shroud (72, 73) of the first rotor blade (48) and the partial span shroud (72, 73) of the second rotor blade (50) at an interference joint (75). The damper (100) is capable of moving relative to the partial span shrouds (72, 73) of both the first rotor blade (48) and the second rotor blade (50).

Description

Technical Field

[0001] The present disclosure generally relates to turbine rotor blades. More specifically, the present disclosure relates to structures for attenuating vibrations in a turbine rotor blade assembly.

[0002] Statement Regarding Federally Sponsored Research or Development

[0003] This invention was made with government support under Contract No. DE-FE0031613 awarded by the U.S. Department of Energy. The government has certain rights in the invention. Background Art

[0004] Turbines are used in a variety of industries and applications for energy transfer purposes. For example, a gas turbine engine typically includes a compressor section, a combustion section, a turbine section, and an exhaust section. The compressor section gradually increases the pressure of the working fluid entering the gas turbine engine and supplies the compressed working fluid to the combustion section. The compressed working fluid and fuel (e.g., natural gas) are mixed and burned in the combustion section in a combustion chamber to generate high-pressure and high-temperature combustion gases. The combustion gases flow from the combustion section into the turbine section, where the combustion gases expand to do work. For example, the expansion of the combustion gases in the turbine section can cause a rotor shaft connected to, for example, a generator to rotate to generate electricity. The combustion gases then leave the gas turbine via the exhaust section.

[0005] Generally, turbine rotor blades are exposed to unsteady aerodynamic loads that cause the rotor blades to vibrate. If these vibrations are not adequately attenuated, they can lead to high-cycle fatigue and premature failure of the blades. In all turbine stages, the last-stage blades (LSBs) are the tallest and thus the most vibration-challenging components of the turbine. Conventional vibration damping methods for turbine blades include platform dampers, damping lacing wires, shrouds, etc.

[0006] Platform dampers are located below the blade platform and are effective for mid-span and long-span blades that have motion at the blade platform. IGT-class aft blades have short spans to reduce blade weight and, in turn, the pulling loads on the rotor, which renders platform dampers ineffective.

[0007] Generally speaking, turbine rotor blades obtain their vibration damping mainly from shrouds. The shrouds can be located at the blade tip (tip shrouds) or at a partial span between the hub and the tip (partial-span shrouds). These shrouds contact adjacent blades and provide vibration damping when they rub against each other.

[0008] In many cases, the partial span shroud contact load may be too high, which prevents the partial span shroud contact surface from sliding and providing vibration damping. One solution to this problem is to add a second partial span shroud to share the contact load. While this improves vibration damping, it results in weight gain and performance degradation due to increased blockage in the flow path. Therefore, it is beneficial to have vibration damping techniques that improve vibration damping without overly blocking the flow path. Additionally, although traditional nodular-sleeve dampers can provide sufficient vibration damping, there is a stiffness loss due to the lack of shroud-to-shroud contact, which makes frequency avoidance difficult.

[0009] Accordingly, a system that provides vibration damping for a rotor blade without loss of stiffness and without creating a large blockage in the flow path is desired in the art. SUMMARY

[0010] Aspects and advantages of the rotor blade assembly and turbine in accordance with the present disclosure will be set forth in part in the following description, or will be obvious from the description, or may be learned by practice of the present technique.

[0011] According to one embodiment, a rotor blade assembly for a turbine is provided. The rotor blade assembly includes a first rotor blade and a second rotor blade positioned adjacent to one another. The first rotor blade and the second rotor blade each include a platform and an airfoil that extends radially outward from a root coupled to the platform to a tip. The airfoil includes a pressure side surface, a suction side surface, and a partial span shroud. The partial span shroud extends from the airfoil and is disposed between the root and the tip. The partial span shroud includes a pressure side portion extending from the pressure side surface and a suction side portion extending from the suction side surface. The suction side portion of the partial span shroud of the first rotor blade and the pressure side portion of the partial span shroud of the second rotor blade form a mating joint with one another. A damper contacts both the partial span shroud of the first rotor blade and the partial span shroud of the second rotor blade at the mating joint. The damper is capable of moving relative to the partial span shrouds of both the first rotor blade and the second rotor blade.

[0012] According to another embodiment, a turbine is provided. The turbine includes a compressor section, a combustor section, and a turbine section. A rotor disk is provided in one of the compressor section or the turbine section. A first rotor blade and a second rotor blade are mounted adjacent to each other on the rotor disk. The first rotor blade and the second rotor blade each include a platform and an airfoil that extends radially outward from a root connected to the platform to a tip. The airfoil includes a pressure side surface, a suction side surface, and a partial span shroud. The partial span shroud extends from the airfoil and is disposed between the root and the tip. The partial span shroud includes a pressure side portion extending from the pressure side surface and a suction side portion extending from the suction side surface. The suction side portion of the partial span shroud of the first rotor blade and the pressure side portion of the partial span shroud of the second rotor blade form a mating joint with each other. A damper contacts both the partial span shroud of the first rotor blade and the partial span shroud of the second rotor blade at the mating joint. The damper is movable relative to the partial span shrouds of both the first rotor blade and the second rotor blade.

[0013] These and other features, aspects, and advantages of the rotor blade assembly and turbine of the present invention will become better understood with reference to the following description and the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present technology and, together with the description, serve to explain the principles of the present technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The complete and enabling disclosure of the rotor blade assembly and turbine of the present invention, including the best mode of making and using the systems and methods of the present invention, to one of ordinary skill in the art is set forth in this specification with reference to the accompanying drawings, in which:

[0015] Figure 1 is a schematic view of a turbine according to an embodiment of the present disclosure;

[0016] Figure 2 shows a perspective view of a rotor blade assembly according to an embodiment of the present disclosure;

[0017] Figure 3 shows according to an embodiment of the present disclosure Figure 2 a top plan view of the rotor assembly shown;

[0018] Figure 4 shows an enlarged perspective view of an airfoil according to an embodiment of the present disclosure;

[0019] Figure 5 shows a cross-sectional side view of a sleeve damper according to an embodiment of the present disclosure;

[0020] Figure 6 shows a perspective view of a rotor blade assembly having a sleeve damper coupled thereto according to an embodiment of the present disclosure;

[0021] Figure 7 is according to an embodiment of the present disclosure Figure 6 a top plan view of the rotor assembly shown;

[0022] Figure 8 shows an expanded sleeve damper according to an embodiment of the present disclosure;

[0023] Figure 9 shows a cross-sectional view of a sleeve damper according to an embodiment of the present disclosure;

[0024] Figure 10 shows a plan view of a rotor assembly with an insert damper according to an embodiment of the present disclosure;

[0025] Figure 11 shows a perspective view of a rotor blade in which an insert damper is positioned according to an embodiment of the present disclosure;

[0026] Figure 12 shows an enlarged plan view of a rotor assembly with a first insert damper and a second insert damper according to an embodiment of the present disclosure;

[0027] Figure 13 shows a perspective view of a rotor blade with a pin damper according to an embodiment of the present disclosure; and

[0028] Figure 14 shows a top view of a rotor assembly with a pin damper according to an embodiment of the present disclosure. Detailed Description

[0029] Reference will now be made in detail to embodiments of the rotor blade assembly and turbine of the present invention, one or more examples of which are shown in the drawings. Each example is provided by way of explanation of the technology of the present invention and not as a limitation of the technology. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the technology of the present invention without departing from the scope or essence of the technology protected by the claims. For example, features shown or described as part of one embodiment can be used in another embodiment to yield yet another embodiment. Accordingly, the present disclosure is intended to cover such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0030] The detailed description uses numerical and alphabetical names to refer to the feature structures in the drawings. Similar or like names in the drawings and the specification have been used to refer to similar or like components of the present invention. As used herein, the terms "first", "second", and "third" may be used interchangeably to distinguish one component from another and are not intended to denote the position or importance of the individual components.

[0031] As used herein, the terms "upstream" (or "upward") and "downstream" (or "downward") refer to the relative direction with respect to the fluid flow in a fluid passage. For example, "upstream" refers to the direction from which the fluid flows, and "downstream" refers to the direction towards which the fluid flows. The term "radially" refers to a relative direction that is substantially perpendicular to the axial centerline of a particular component, the term "axially" refers to a relative direction that is substantially parallel and / or coaxially aligned with the axial centerline of a particular component, and the term "circumferentially" refers to a relative direction that extends around the axial centerline of a particular component. Terms indicating approximation, such as "substantially" or "about", include values within plus or minus ten percent of the specified value. When used in the context of an angle or direction, such terms include within plus or minus ten degrees of the stated angle or direction. For example, "substantially vertical" includes directions within plus or minus ten degrees of vertical in any direction (e.g., clockwise or counterclockwise).

[0032] Referring now to the drawings, Figure 1 there is shown a schematic view of an embodiment of a turbine, which in the illustrated embodiment is a gas turbine 10. Although an industrial or land-based gas turbine is shown and described herein, the present disclosure is not limited to land-based and / or industrial gas turbines unless otherwise specified in the claims. For example, the invention as described herein can be used in any type of turbine, including but not limited to steam turbines, aircraft gas turbines, or marine gas turbines.

[0033] As shown, the gas turbine 10 generally includes an inlet section 12, a compressor section 14 disposed downstream of the inlet section 12, a plurality of burners (not shown) within a burner section 16 disposed downstream of the compressor section 14, a turbine section 18 disposed downstream of the burner section 16, and an exhaust section 20 disposed downstream of the turbine section 18. Additionally, the gas turbine 10 may include one or more shafts 22 coupled between the compressor section 14 and the turbine section 18.

[0034] The compressor section 14 generally may include a plurality of rotor disks 24 (one of which is shown) and a plurality of rotor blades 26 that extend radially outward from each rotor disk 24 and are connected to each rotor disk. Each rotor disk 24 in turn may be coupled to or form a part of a shaft 22 that extends through the compressor section 14.

[0035] The turbine section 18 generally may include a plurality of rotor disks 28 (one of which is shown) and a plurality of rotor blades 30 that extend radially outward from each rotor disk 28 and are interconnected to each rotor disk. Each rotor disk 28 in turn may be coupled to or form a part of a shaft 22 that extends through the turbine section 18. The turbine section 18 also includes an outer casing 31 that circumferentially surrounds a portion of the shaft 22 and the rotor blades 30, thereby at least partially defining a hot gas path 32 through the turbine section 18.

[0036] During operation, a working fluid such as air flows through the inlet section 12 and into the compressor section 14 where the air is progressively compressed, thereby providing pressurized air to the burners of the compressor section 16. The pressurized air is mixed with fuel and burned within each burner to produce combustion gases 34. The combustion gases 34 flow from the burner section 16 through the hot gas path 32 and into the turbine section 18 where energy (kinetic and / or thermal) is transferred from the combustion gases 34 to the rotor blades 30, causing the shaft 22 to rotate. The mechanical rotational energy can then be used to power the compressor section 14 and / or generate electricity. The combustion gases 34 that exit the turbine section 18 can then be exhausted from the gas turbine 10 via the exhaust section 20.

[0037] Figure 2 A perspective view of a rotor blade assembly 45 according to an embodiment of the present disclosure that can be incorporated in any stage of the turbine section 18 or the compressor section 14 is provided, and Figure 3 is a top plan view of the rotor assembly 45. In an exemplary embodiment, the rotor blade assembly 45 can be used within the turbine section 18. As Figure 2 and Figure 3 collectively show, the turbine rotor blade assembly 45 includes a rotor disk 46 that can represent the rotor disk 24 and / or the rotor disk 28 described herein. A first rotor blade 48 and a second rotor blade can be positioned adjacent to each other and mounted to the rotor disk 46. In an exemplary embodiment, the first rotor blade 48 and the second rotor blade 50 can be positioned adjacent to each other such that there is no rotor blade between the first rotor blade 48 and the second rotor blade 50.

[0038] In a particular configuration, each of the rotor blades 48, 50 can include a mounting portion 74 (such as a dovetail joint) that is configured to connect and / or secure the rotor blades 48, 50 to the rotor disk 46. As Figure 2As shown, each of the rotor blades 48, 50 may include a platform 66 and a fin 52 extending from the platform 66. In many embodiments, the fin 52 may extend radially outward from the platform relative to the axial centerline of the gas turbine 10. In various embodiments, the fin 52 includes a pressure side surface 54 and an opposite suction side surface 56. The pressure side surface 54 and the suction side surface 56 intersect or meet at a leading edge 58 and a trailing edge 60 of the fin 52. The leading edge 58 and the trailing edge 60 may be spaced apart from each other and define the termini of the fin 52 in the axial direction. A chord line (not shown) extends between the leading edge 58 and the trailing edge 60 such that the pressure side surface 54 and the suction side surface 56 extend along the chord or chordwise between the leading edge 58 and the trailing edge 60.

[0039] In many embodiments, the pressure side surface 54 generally defines the aerodynamic, concave outer surface of the fin 52. Similarly, the suction side surface 56 may generally define the aerodynamic, convex outer surface of the fin 52. The leading edge 58 of the fin 52 may be the first portion of the fin 52 to engage (i.e., be exposed to) the combustion gases along the hot gas path 32. The combustion gases may be directed along the aerodynamic profile of the fin 52 (i.e., along the suction side surface 56 and the pressure side surface 54) and then discharged at the trailing edge 60.

[0040] As Figure 2 shown, the fin 52 includes a root or first end 64 that intersects and extends radially outward from the platform 66 of the turbine rotor blade 50. The fin 52 radially terminates at a second end or tip 68 of the fin 52. The root 64 of the fin 52 may define the intersection between the fin 52 and the platform 66. The tip 68 is disposed radially opposite the root 64. Thus, the tip 68 may generally define the radially outermost portion of the rotor blade 50 and may thus be configured to be positioned adjacent a stationary shroud or seal (not shown) of the turbine section 18.

[0041] The pressure side surface 54 and the suction side surface 56 extend in the span and define the span length 70 of the fin 52 between the root 64 and / or the platform 66 and the tip 68 of the fin 52. In other words, each rotor blade 50 includes a fin 52 having opposite pressure side surface 54 and suction side surface 56 that extend chordwise or chordwise between opposite leading edge 58 and trailing edge 60 and spanwise or in the span direction 70 between the root 64 and the tip 68 of the fin 52.

[0042] The span length 70 can be measured from the root 64 to the tip 68 of the vane 52. A percentage of the span length 70 can be used to indicate a position along the span length 70. For example, "0% span" can refer to the root 64 of the vane 52. Similarly, "100% span" can refer to the tip 68 of the vane. Thus, the term "partial span" can refer to a position along the span length 70 that is between 0% span and 100% span but does not include the endpoint values.

[0043] As Figure 2 and Figure 3 Collectively shown, the first rotor blade 48 can include a first partial-span shroud 72, and the second rotor blade 50 can include a second partial-span shroud 73. Each of the partial-span shrouds 72, 73 can extend from a respective vane 52 of the rotor blades 48, 52. In many embodiments, the partial-span shrouds 72, 73 can each be disposed between the root 64 and the tip 68 of the respective vane 52. For example, the partial-span shrouds 72 and the span shroud 73 of the rotor blade 48 and the rotor blade 50 can be disposed at a common location along the length of the respective vane 52, e.g., between the root 64 and the tip 68 of the vane 52. In many embodiments, the partial-span shrouds 72, 73 can be spaced apart from both the root 64 and the tip 68 of the respective vane 52. The partial-span shrouds 72, 73 can be used to connect adjacent rotor blades 48, 50. The connection of the adjacent rotor blades 48, 50 can advantageously attenuate the operating vibrations experienced by the rotor blades 48, 50, which means that the rotor blades 48, 50 are subject to less mechanical stress during operation and deteriorate more slowly.

[0044] In many embodiments, the first partial-span shroud 72 and the second partial-span shroud 73 can each include a pressure-side portion 76 extending from the pressure-side surface 54 and a suction-side portion 74 extending from the suction-side surface 56. As shown, the pressure-side portion 76 of the partial-span shroud 72 of the first rotor blade 48 is coupled to the suction-side portion 74 of the partial-span shroud 73 of the second rotor blade 50. In many embodiments, the pressure-side portion 76 and the suction-side portion 74 of each partial-span shroud 72, 73 can extend relative to each other and be coupled to the partial-span shrouds 72, 73 of the adjacent rotor blades 48, 50. In various embodiments, the pressure-side portion 76 and the suction-side portion 74 are both cantilevered such that they extend from respective attachment ends 78, 79 connected to the vane 52 to free ends 80, 81 away from the vane 52. Thus, the free end 80 of the pressure-side portion 76 of the first partial-span shroud 72 of the first rotor blade 48 is disposed at least near the free end 81 of the suction-side portion 74 of the second partial-span shroud 73 of the second rotor blade 50. In an exemplary embodiment, when the rotor assembly is fully assembled, the partial-span shrouds 72, 73 of the rotor blades 48, 50 can extend circumferentially and define a shroud ring concentric with the rotor disk 46.

[0045] As Figure 3 shown, both the suction side portion 74 and the pressure side portion 76 of the partial span shrouds 72, 73 can each include respective contact surfaces 82, 84 that are oriented relative to each other. For example, the contact surface 82 of the suction side portion 74 of the first partial span shroud 72 can extend from the attachment end 79 generally inclined to the axial direction to the free end 81. Similarly, the contact surface 84 of the pressure side portion 76 of the second partial span shroud 73 can extend from the attachment end 78 generally inclined to the axial direction to the free end 80. As Figure 3 shown, the contact surface 82 of the suction side portion 74 of the first partial span shroud 72 can correspond to and contact the contact surface 84 of the pressure side portion 76 of the second partial span shroud 73 to couple the rotor blades 48, 50 together. In many embodiments, the contact surface 82 and the contact surface 84 can move relative to each other. For example, during operation of the gas turbine 10, the contact surface 82 and the contact surface 84 can rub against each other to dissipate, in a frictional manner, vibrations of the rotor blades 48, 50 that could cause damage.

[0046] In many embodiments, the suction side portion 74 of the first partial span shroud 72 of the first rotor blade 48 and the pressure side portion 76 of the second partial span shroud 73 of the second rotor blade 50 can form a joint 75 with each other. For example, during operation of the gas turbine 10, the suction side portion 74 of the first partial span shroud 72 and the pressure side portion 76 of the partial span shroud 73 can rub against each other at an interference joint 75 (which is provided between the partial span shrouds 72, 73) to dissipate, in a frictional manner, vibrations of the rotor blades 48, 50 that could cause damage.

[0047] In an exemplary embodiment, one or more dampers (such as the sleeve damper 100, the plug damper 200, and / or the pin damper 400 described herein) can contact both the partial span shrouds 72, 73 at the interference joint 75 to advantageously increase the vibration damping of the partial span shrouds 72, 73 and extend the overall life of the rotor blades 48, 50. For example, in many embodiments, the damper can move relative to the first partial span shroud 72 of the first rotor blade 48 and the second partial span shroud 73 of the second rotor blade 50 to dissipate, in a frictional manner, vibrations of the rotor blades 48, 50. For example, the damper can move and / or slide relative to the first partial span shroud 72 of the first rotor blade 48 and the second partial span shroud 73 of the second rotor blade 50 to dissipate, in a frictional manner, vibrations of the rotor blades 48, 50.

[0048] Figure 4Shows an enlarged perspective view of a first rotor blade 48 according to an embodiment of the present disclosure. As shown, the sleeve damper 100 is slidably coupled to the partial span shroud 72 of the airfoil 52 such that the sleeve damper 100 is capable of moving relative to the partial span shroud 72. In many embodiments, the sleeve damper 100 may be a hollow member that surrounds the partial span shroud 72. For example, the sleeve damper 100 may surround the partial span shroud 72 in both the axial and radial directions. In various embodiments, the sleeve damper 100 may have a shape corresponding to (or mimicking) the outer shape of the partial span shroud 72. As Figure 5 shown, which shows a cross-sectional view of the sleeve damper 100, the sleeve damper 100 may include an inner surface 102 that corresponds to (or mimics) the outer surface 86 of the partial span shroud 72 in order to contact the entire partial span shroud 72, thereby better utilizing the movement between the rotor blades 48, 50 and dissipating vibrations in a frictional manner.

[0049] As Figure 5 shown, the sleeve damper 100 may define a teardrop-shaped opening 104. For example, the sleeve damper 100 may include a leading edge 106 having a generally circular shape, a trailing edge 108 having a generally circular shape and axially separated from the leading edge, and a pair of sides 109 extending generally straight between the leading edge 106 and the trailing edge 108. Both the leading edge 106 and the trailing edge 108 of the sleeve damper 100 may be generally rounded semi-circular shapes that form the axial ends of the sleeve damper 100. In many embodiments, the width 110 of the sleeve damper 100 may taper from the leading edge 106 to the trailing edge 108 of the sleeve damper 100 such that the sides 109 converge towards each other generally in the axial direction A.

[0050] Figure 6 is a perspective view of a rotor blade assembly 45 having a sleeve damper 100 coupled thereto according to an embodiment of the present disclosure, and Figure 7 is Figure 6 a top plan view of the rotor assembly 45 shown. As Figure 6 and Figure 7As shown, for clarity, the portions of the partial span shrouds 72, 73 covered by the sleeve damper 100 are shown in dashed lines. As shown, when the first rotor blade 48 and the second rotor blade 50 are installed in the complete rotor assembly 45, the sleeve damper 100 can surround a portion of the first partial span shroud 72 and a portion of the second partial span shroud 73 such that the sleeve damper 100 partially contacts both the first partial span shroud 72 and the second partial span shroud 73 of the rotor blades 48, 50. In this way, the sleeve damper 100 utilizes the relative movement between the partial span shrouds 72, 73 of the rotor blades 48, 50 to increase the frictional damping therebetween. In this way, the sleeve damper 100 is configured to advantageously reduce the vibrations experienced by the rotor blades 48, 50 during operation. For example, the sleeve damper 100 provides an increased surface area in contact with both the partial span shrouds 72, 73, which advantageously increases the amount of frictional damping between the partial span shrouds 72, 73, thereby reducing the amount of vibrations that could cause damage to the rotor blades 48, 50.

[0051] In an exemplary embodiment, the sleeve damper 100 can contact the outer surface 86 of the first partial span shroud 72 and the outer surface 87 of the second partial span shroud 73 such that the sleeve damper 100 is positioned within the flow of the combustion gas 34 and is directly exposed to the flow. In such embodiments, the sleeve damper 100 can include an outer surface 112 that corresponds to the contours of the outer surfaces 86, 87 of the partial span shrouds 72, 73 in order to provide frictional damping to the rotor blades 48, 50 without impeding (or blocking) the flow of the combustion gas 34 above the partial span shrouds 72, 73.

[0052] In a particular embodiment, the sleeve damper 100 can surround the suction side portion 74 of the first partial span shroud 72 and the pressure side portion 76 of the second partial span shroud 73. As Figure 7 shown, the sleeve damper 100 can extend between the suction side surface 56 of the first rotor blade 48 and the pressure side surface 54 of the second rotor blade 50. In this way, the suction side surface 56 and the pressure side surface 54 of the adjacent rotor blades 48, 50 form the boundaries of the sleeve damper 100. For example, the sleeve damper 100 can move and / or slide on the outer surfaces 86, 87 of the partial span shrouds 72, 73 of the adjacent rotor blades 48, 50, but the suction side surface 56 and the pressure side surface 54 of the fin 52 form boundaries that prevent the sleeve damper 100 from sliding too far and disengaging from the partial span shrouds 72, 73.

[0053] Figure 8An alternative embodiment of the sleeve damper 100 is shown, where the sleeve has been deployed to show one or more cuts or openings 114 that may be defined thereon. In such an embodiment, the openings are used to advantageously reduce the weight of the sleeve damper 100. As Figure 8 shown, the openings may be defined within the side portions 109 of the sleeve damper 100 to remove a majority of the weight of the sleeve damper.

[0054] Figure 9 A cross-sectional view of another alternative embodiment of the sleeve damper 100 is shown. As shown, one of the side portions 109 in the pair of side portions 109 may be completely removed to reduce the total weight of the sleeve damper 100. In such an embodiment, the sleeve damper 100 may include only one side portion 109 extending between the leading edge 106 and the trailing edge 108. As shown, the sleeve damper 100 may define a gap 115 between the leading edge 106 and the trailing edge 108 of the sleeve damper 100.

[0055] Alternatively or in addition to the sleeve damper 100 described above, the rotor assembly 45 may further include an insert damper 200 that contacts both the first partial-span shroud 72 of the first rotor blade 48 and the second partial-span shroud 73 of the second rotor blade 50 to advantageously increase the vibration damping of the partial-span shrouds 72, 73 and extend the overall life of the rotor blades 48, 50. For example, the insert damper 200 may contact only the inner surfaces of the partial-span shrouds 72, 73 of the rotor blades 48, 50 such that the insert damper 200 is not exposed to the combustion gases 34 passing outside of the partial-span shrouds 72, 73.

[0056] Figure 10 An embodiment of a rotor assembly 45 having an insert damper 200 in accordance with an embodiment of the present disclosure is shown. As Figure 10 shown, the first partial-span shroud 72 of the first rotor blade 48 and the second partial-span shroud 73 of the rotor blade 50 may each define one or more internal cavities, e.g., a first internal cavity 202 defined within the pressure-side portion 76 of the partial-span shrouds 72, 73 and a second internal cavity 203 defined within the suction-side portion 74 of the partial-span shrouds 72, 73. As Figure 10As shown, when the rotor blades 48, 50 are positioned adjacent to each other on the rotor disk 46, the inner cavities 202, 203 of the partial span shrouds 72, 73 combine to form an inner chamber 204. For example, as shown, the pressure side portion 76 of the first partial span shroud 72 may be connected to the suction side portion 74 of the second partial span shroud 73 such that the corresponding inner cavities 202, 203 are aligned and form the inner chamber 204. One or more plug dampers 200 may be positioned within the inner chamber 204. For example, as shown, one or more plug dampers 200 may extend between the first cavity 202 and the second cavity 203 such that the plug damper 200 contacts the inner surfaces of both the first partial span shroud 72 and the second partial span shroud 73. In this way, the plug damper 200 is received within and contacts the partial span shrouds 72 and 73, which advantageously allows the plug damper 200 to provide frictional damping to the rotor blades 48, 50 without impeding the flow of the combustion gas 34.

[0057] Figure 11 A perspective view of another embodiment of the first rotor blade 48 in which a plug damper 300 is positioned is shown. Although Figure 11 only the first rotor blade 48 is shown, it should be understood that the features shown and described with reference to the first rotor blade 48 may be incorporated into the second rotor blade 50. As Figure 11 shown, the plug damper 300 may extend through the entire first partial span shroud 72. For example, as shown, the plug damper 300 may extend from the suction side portion 76 of the partial span shroud 72 through the fin 52 to the pressure side portion 74 of the partial span shroud 72.

[0058] Figure 12 A rotor assembly 45 is shown in which the first rotor blade 48 and the second rotor blade 50 are positioned directly adjacent to each other, e.g., mounted directly adjacent to each other on the rotor disk 46 such that no rotor blade is positioned between the first rotor blade 48 and the second rotor blade 50 ( Figure 2 ). As shown, the plug damper 300 may be the first plug damper 300 positioned within the first partial span shroud 72, and the rotor assembly may further include a second plug damper 302 positioned within the second partial span shroud 73. In an exemplary embodiment, the first plug damper 300 and the second plug damper 302 may be received within the partial span shrouds 72, 73 such that they provide frictional damping to the rotor blades 48, 50 without being exposed to the combustion gas 34. Both the first plug damper 300 and the second plug damper 302 are capable of slidingly moving relative to the first partial span shroud 72, the second partial span shroud 73, and each other.

[0059] In certain embodiments, as shown, the first plug damper 300 may extend continuously through the airfoil 52 of the first rotor blade and across the interference joint 75, and the second plug damper 302 may extend continuously through the airfoil 52 of the second rotor blade 50. For example, the first plug damper 300 may extend continuously (i.e., without breaks or separations) within the first partial span shroud 72 and into the second partial span shroud 73. For example, as shown, the first plug damper 300 may extend from a first end 304 at a free end 81 of the suction side portion 76 of the first partial span shroud through the airfoil 52 of the first rotor blade 48, across the interference joint 75, to a second end 306 disposed within the suction side portion 76 of the second partial span shroud 73. In this way, the first plug damper 300 may extend continuously between the first partial span shroud 72 and the second partial span shroud 73. Similarly, the second plug damper 302 may extend continuously within the second partial span shroud 72, i.e., without breaks or separations. For example, as shown, the second plug damper 302 may extend from a first end 308 at a free end 81 of the suction side portion 76 of the second partial span shroud through the airfoil 52 of the second rotor blade 50 to a second end 310. Although only two rotor blades 48, 50 are shown in Figure 12 FIG. 1, in a complete rotor assembly circumferentially extending around the axis 22 of the turbine 18, the partial span shroud of each rotor blade may include a plug damper that extends within the partial span shroud and into an adjacent partial span shroud such that the plug dampers form a circumferential ring around the axis 22 of the turbine 18.

[0060] In many embodiments, such as Figure 12As shown, the first insert damper 300 can contact and overlap with the second insert damper 302. For example, the first end 308 of the second insert damper 302 can circumferentially overlap with the second end 306 of the first insert damper 300 such that the radially outer surface 312 of the first insert damper 300 contacts the radially inner surface 314 of the second insert damper 302. In this way, the insert dampers 300, 302 can movably contact the inner surfaces of the first partial span damper 72 and the second partial span damper 73, which allows the first insert dampers 300, 302 to provide frictional damping to the rotor blades 48, 50 by utilizing the relative movement between the partial span shrouds 72, 73. For example, the insert dampers 300, 302 are configured to advantageously reduce the vibrations experienced by the rotor blades 48, 50 during operation. For example, the insert dampers 300, 302 provide an increased surface area of internal contact with both of the partial span shrouds 72, 73, which advantageously increases the amount of frictional damping between the partial span shrouds 72, 73, thereby reducing the amount of vibrations that could cause damage to the rotor blades 48, 50. Additionally, since the insert dampers 300, 302 are positioned within the partial span shrouds 72, 73, they do not cause any blockage or obstruction to the flow of the combustion gas 34 above the fins 52.

[0061] Figure 13 A perspective view of a first rotor blade 48 having a pin damper 400 extending from a first partial span shroud 72 is shown, and Figure 14 A top view of a rotor assembly 45 having a pin damper 400 positioned within and extending between a first partial span shroud 72 and a second partial span shroud 73 is shown. As Figure 13 and Figure 14 collectively show, the pin damper 400 can be a generally cylindrical damper that extends within and between the partial span shrouds 72, 73 so as to dissipate vibrations between the rotor blades 48, 50 in a frictional manner. In many embodiments, the rotor assembly 45 can include a first pin damper 402 and a second pin damper 404. As Figure 13As shown, the first pin damper 402 and the second pin damper may have different diameters. For example, the first pin damper 402 may have a smaller diameter than the second pin damper 404. The first pin damper 402 and the second pin damper 404 may each be positioned within and extend between a first partial-span shroud 72 of the first rotor blade 48 and a second partial-span shroud 73 of the second rotor blade 50. As shown, each of the pin dampers 402, 404 may contact both the inner surface of the first partial-span shroud 72 and the inner surface of the second partial-span shroud 73 so as to utilize the relative movement between the partial-span shrouds 72, 73 and generate frictional damping. In this way, the pin dampers 402, 404 are configured to advantageously reduce the vibrations experienced by the rotor blades 48, 50 during operation. For example, the insert dampers 402, 404 provide an increased surface area of internal contact with both of the partial-span shrouds 72, 73, which advantageously increases the amount of frictional damping between the partial-span shrouds 72, 73, thereby reducing the amount of vibration that could cause damage to the rotor blades 48, 50. In addition, since the pin dampers 402, 404 are housed within the partial-span shrouds 72, 73, they do not cause any blockage or obstruction to the flow of the combustion gas 34 above the fins 52.

[0062] Although various dampers 100, 200, 300, 400 are described herein in the context of partial-span shrouds 72, 73. It is contemplated within the scope of the present invention that the dampers 100, 200, 300, 400 may be used on tip-span shrouds. For example, the dampers 100, 200, 300, 400 may be positioned above or within the tip-span shroud so as to provide increased vibration damping without a significant loss of stiffness.

[0063] The dampers 100, 200, 300, 400 described herein have many advantages over existing designs. For example, the dampers 100, 200, 300, 400 all provide vibration damping for the rotor blades without loss of stiffness, add a minimum amount of additional weight to the rotor assembly, and if worn, they can be easily replaced or repaired. In addition, the dampers 100, 200, 300, 400 described herein can be easily tuned by adjusting the weight, cause little or no blockage to the flow of the combustion gas above the rotor blades, and provide vibration damping even when the partial-span shrouds 72, 73 are not in contact with each other (such as under partial-speed operating conditions). In addition, the dampers 100, 200, 300, 400 provide increased flexibility in the design of the rotor blade shrouds due to the increased damping at low partial-speed conditions. For example, the contact load between the shrouds may have increased flexibility due to the dampers 100, 200, 300, 400.

[0064] This written description uses examples to disclose the invention, including the best mode, and also enables any person skilled in the art to practice the invention, including making and using any device or system and performing any combined method. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. If these other examples include structural elements that are not different from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims, then these other examples are intended to be within the scope of the claims.

Claims

1. A rotor blade assembly (45) for a turbine, the rotor blade assembly (45) comprising: a first rotor blade (48) and a second rotor blade (50) positioned adjacent to each other, each of the first rotor blade (48) and the second rotor blade (50) comprising: a platform (66); and a fin (52) that extends radially outward from a root (64) connected to the platform (66) to a tip (68), the fin (52) comprising a pressure side surface (54), a suction side surface (56), and a partial span shroud (72, 73) that extends from the fin (52) and is disposed between the root (64) and the tip (68), the partial span shroud (72, 73) having a pressure side portion (76) extending from the pressure side surface (54) and a suction side portion (74) extending from the suction side surface (56), wherein the suction side portion (74) of the partial span shroud (72, 73) of the first rotor blade (48) and the pressure side portion (76) of the partial span shroud (72, 73) of the second rotor blade (50) form a mating joint (75) with each other; and first and second pin dampers (402, 404) each positioned within and extending between the partial span shrouds (72, 73) of the first rotor blade (48) and the second rotor blade (50) at the mating joint (75), wherein the first and second pin dampers (402, 404) are movable relative to the partial span shrouds (72, 73) of both the first rotor blade (48) and the second rotor blade (50).

2. The rotor blade assembly (45) according to claim 1, further comprising a sleeve damper (100) in contact with an outer surface (86) of the partial span shroud (72, 73) of the first rotor blade (48) and an outer surface (86) of the partial span shroud (72, 73) of the second rotor blade (50).

3. The rotor blade assembly (45) according to claim 2, wherein the sleeve damper (100) surrounds the suction side portion (74) of the partial span shroud (72, 73) of the first rotor blade (48) and the pressure side portion (76) of the partial span shroud (72, 73) of the second rotor blade (50).

4. The rotor blade assembly (45) according to claim 2, wherein the sleeve damper (100) extends between the suction side surface (56) of the first rotor blade (48) and the pressure side surface (54) of the second rotor blade (50).

5. The rotor blade assembly (45) according to claim 2, wherein the sleeve damper (100) defines one or more openings (104).

6. A turbine, the turbine comprising: Compressor section (14); Combustor section (16); Turbine section (18); A rotor disk (24) disposed in one of the compressor section (14) or the turbine section (18), with a first rotor blade (48) and a second rotor blade (50) mounted adjacent to each other on the rotor disk, the first rotor blade (48) and the second rotor blade (50) each comprising: A platform (66); and A fin (52) that extends radially outward from a root (64) connected to the platform (66) to a tip (68), the fin (52) including a pressure side surface (54), a suction side surface (56), and a partial span shroud (72, 73) that extends from the fin (52) and is disposed between the root (64) and the tip (68), the partial span shroud (72, 73) having a pressure side portion (76) extending from the pressure side surface (54) and a suction side portion (74) extending from the suction side surface (56), wherein the pressure side portion (76) of the partial span shroud (72, 73) of the first rotor blade (48) and the suction side portion (74) of the partial span shroud (72, 73) of the second rotor blade (50) form a mating joint (75) with each other; and First and second pin dampers (402, 404) each positioned within and extending between the partial span shrouds (72, 73) of the first rotor blade (48) and the second rotor blade (50) at the mating joint (75), wherein the first and second pin dampers (402, 404) are movable relative to the partial span shrouds (72, 73) of both the first rotor blade (48) and the second rotor blade (50).

7. The turbine according to claim 6, further comprising a sleeve damper (100) in contact with an outer surface (86) of the partial span shroud (72, 73) of the first rotor blade (48) and an outer surface (86) of the partial span shroud (72, 73) of the second rotor blade (50).

8. The turbine according to claim 7, wherein the sleeve damper (100) surrounds the suction side portion (74) of the partial span shroud (72, 73) of the first rotor blade (48) and the pressure side portion (76) of the partial span shroud (72, 73) of the second rotor blade (50).

9. The turbine according to claim 7, wherein the sleeve damper (100) extends between the suction side surface (56) of the first rotor blade (48) and the pressure side surface (54) of the second rotor blade (50).

10. The turbine according to claim 7, wherein the sleeve damper (100) defines one or more openings (104).

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