Damper stacks for turbine rotor blades

Abstract

The present invention is entitled a damper stack for turbine rotor blades. The invention provides a damper stack (70), rotor blades (26, 30), and a turbine. The rotor blade (26) includes a body comprising a shank (38) and blades (36) extending radially outward from the shank (38). The rotor blade (26, 30) also includes a platform (42) surrounding the body, the platform (42) including ramps (56, 58). The rotor blade (26, 30) also includes a damper stack (70) disposed at the ramps (56, 68) and extending generally in an axial direction. The damper stack (70) includes a plurality of damper pins (72), each of the plurality of damper pins (72) contacting an adjacent damper pin (72).

Description

Technical Field

[0001] This disclosure relates in general to rotor blades for turbines, and more specifically to a stack of dampers used within rotor blades. Background Technology

[0002] 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 this compressed working fluid to the combustion section. The compressed working fluid and fuel (e.g., natural gas) mix in the combustion section and are burned in the combustion chamber to produce high-pressure, high-temperature combustion gases. The combustion gases flow from the combustion section into the turbine section, where they 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 exit the gas turbine via the exhaust section.

[0003] Compressor and turbine sections typically comprise multiple rotor blades, usually arranged in multiple stages. During engine operation, vibrations can be introduced into the rotor blades. For example, flow fluctuations of the compressed working fluid or hot combustion gas or steam can cause rotor blade vibration. A fundamental design consideration for turbine designers is to avoid or minimize resonance with the natural frequencies of the rotor blades and dynamic stresses arising from forced responses and / or aeroelastic instabilities, thereby controlling high-cycle fatigue of the rotor blades.

[0004] To improve the high-cycle fatigue life of rotor blades, vibration dampers are typically provided below and / or between the platform to frictionally dissipate vibrational energy and reduce the corresponding amplitude of vibrations during operation. The amount of vibrational energy removed by the vibration damper is a function of the dynamic weight of the vibration damper and the responsive load.

[0005] While known dampers may be largely adequate during typical operation, improvements in overall damper effectiveness are still desirable. For example, one problem with many known dampers is that they provide damping only at isolated locations in contact with the associated rotor blades (such as at the ends and possibly at the center). Another problem with many known dampers is their inability to adapt to complex platform shapes, such as those including curved sections.

[0006] Therefore, there is a need in the art for improved damper designs. Specifically, damper designs that provide improved damping along the entire length of the damper (e.g., by providing increased rotor blade contact) would be advantageous. Furthermore, damper designs that adapt to complex platform shapes would be advantageous. Summary of the Invention

[0007] The aspects and advantages of the damper stacks, rotor blades and turbines according to this disclosure will be set forth in part in the following description, or may be apparent from the description, or may be learned by practice of the art.

[0008] According to one embodiment, a rotor blade for a turbine is provided. The rotor blade includes a body comprising a shank and blades extending radially outward from the shank. The rotor blade also includes a platform surrounding the body, the platform including an inclined plane. The rotor blade further includes a damper stack disposed at the inclined plane and extending generally in an axial direction. The damper stack includes a plurality of damper pins, each of the plurality of damper pins contacting an adjacent damper pin.

[0009] According to another embodiment, a turbine is provided. The turbine includes a compressor section, a combustor section, and a turbine section. The turbine also includes a plurality of rotor blades disposed in at least one of the compressor section or the turbine section. Each of the plurality of rotor blades includes a body including a shank and blades extending radially outward from the shank. Each of the plurality of rotor blades also includes a platform surrounding the body, the platform including an inclined surface. Each of the plurality of rotor blades also includes a damper stack disposed at the inclined surface and extending generally in an axial direction. The damper stack includes a plurality of damper pins, each of the plurality of damper pins contacting an adjacent damper pin.

[0010] These and other features, aspects, and advantages of the damper stack, rotor blades, 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 technology and, together with the description, serve to explain the principles of the technology. Attached Figure Description

[0011] This specification sets forth, with reference to the accompanying drawings, a complete and feasible disclosure of the damper stacks, rotor blades, and turbines of the present invention, which will be of ordinary skill in the art, including the best mode for manufacturing and using the systems and methods of the present invention, wherein:

[0012] Figure 1 A schematic diagram of a turbine according to an embodiment of the present disclosure is shown;

[0013] Figure 2 A perspective view of a rotor blade according to an embodiment of the present disclosure is shown;

[0014] Figure 3 A perspective view of rotor blades according to other embodiments of this disclosure is shown;

[0015] Figure 4This is a side view showing adjacent rotor blades according to an embodiment of the present disclosure;

[0016] Figure 5 This is a perspective view of a damper stack according to an embodiment of this disclosure;

[0017] Figure 6 This is a cross-sectional view of a damper stack according to an embodiment of this disclosure;

[0018] Figure 7 This is a cross-sectional view of a damper stack according to other embodiments of this disclosure; and

[0019] Figure 8 This is a cross-sectional view of a damper stack according to other embodiments of this disclosure. Detailed Implementation

[0020] Reference will now be made in detail to embodiments of the damper stack, rotor blades, and turbine of the present invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation of the technology and not as a limitation thereof. Indeed, it will be apparent to those skilled in the art that modifications and variations may be made to the technology of the invention without departing from the scope or spirit of the technology of the invention as protected by the claims. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, this disclosure is intended to cover these modifications and variations that fall within the scope of the appended claims and their equivalents.

[0021] The detailed description uses numbers and letters to refer to feature structures in the drawings. Similar or analogous names in the drawings and description have been used to refer to similar or analogous parts of the invention. As used herein, the terms "first," "second," and "third" are used interchangeably to distinguish one part from another and are not intended to indicate the location or importance of the various parts.

[0022] Now refer to the attached diagram, Figure 1 A schematic diagram of one embodiment of a turbine is shown, which in the illustrated embodiment is a gas turbine 10. Although industrial or land-based gas turbines are shown and described herein, this disclosure is not limited to land-based and / or industrial gas turbines unless otherwise specified in the claims. For example, the damping techniques described herein can be used in any type of turbine, including but not limited to steam turbines, aircraft gas turbines, or marine gas turbines.

[0023] As shown in the figure, the gas turbine 10 typically includes an inlet section 12, a compressor section 14 disposed downstream of the inlet section 12, a plurality of burners (not shown) disposed in 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 connected between the compressor section 14 and the turbine section 18.

[0024] The compressor section 14 may typically include a plurality of rotor disks 24 (one of the plurality of rotor disks is shown) and a plurality of rotor blades 26 extending radially outward from each rotor disk 24 and connected to each rotor disk. Each rotor disk 24 may then be coupled to or form an extension of shaft 22 through a portion of the compressor section 14.

[0025] Turbine section 18 typically includes a plurality of rotor disks 28 (one of the plurality of rotor disks is shown) and a plurality of rotor blades 30 extending radially outward from each rotor disk 28 and interconnecting to each rotor disk. Each rotor disk 28 may then be coupled to or form an extension of shaft 22 through a portion of turbine section 18. Turbine section 18 also includes an outer housing 31 that circumferentially surrounds a portion of shaft 22 and rotor blades 30, thereby at least partially defining a hot gas path 32 through turbine section 18.

[0026] During operation, a working fluid, such as air, flows through inlet section 12 and into compressor section 14, where the air is gradually compressed to supply pressurized air to the combustors in combustion section 16. The pressurized air mixes with fuel and burns in each combustor to produce combustion gases 34. Combustion gases 34 flow from combustor section 16 through hot gas path 32 into turbine section 18, where energy (kinetic and / or thermal) is transferred from combustion gases 34 to rotor blades 30, causing shaft 22 to rotate. This mechanical rotational energy can then be used to power compressor section 14 and / or to generate electricity. The combustion gases 34 exiting turbine section 18 can then be discharged from gas turbine 10 via exhaust section 20.

[0027] Figure 2 and Figure 3 An embodiment of a rotor blade according to an embodiment of the present disclosure is shown. In the illustrated embodiment, the rotor blade is a turbine blade or fan blade 30, but in an alternative embodiment, the rotor blade may be a compressor blade or fan blade 26.

[0028] The rotor blade 30 may include a body comprising a vane 36 and a shank 38. The vane 36 may extend radially outward from and be positioned within the shank 38. The shank 38 may include a root or dovetail 40 which may be attached to the rotor disk 28 to facilitate rotation of the rotor blade 30.

[0029] The blade 36 may have a generally aerodynamic profile. For example, the blade 36 may have an outer surface that defines a pressure side and a suction side, each extending between a leading edge and a trailing edge. The outer surface of the shank 38 may include a pressure side, a suction side, a leading edge surface, and a trailing edge surface.

[0030] Platform 42 typically surrounds the main body. A typical platform may be located at the junction or transition between the vane 36 and the shank 38, and may extend outward in generally axial and tangential directions, as shown. In the turbine section 18, platform 42 typically serves as a radially inward flow boundary for the combustion gas 34 flowing through the hot gas path 32. Platform 42 may include a leading edge surface 52 axially spaced from a trailing edge surface 54. The leading edge surface 52 is positioned in the flow of combustion gas 34, and the trailing edge surface 54 is positioned downstream of the leading edge surface 52. Furthermore, platform 42 may include a pressure side ramp 56 circumferentially spaced from a suction side ramp 58.

[0031] In some implementation schemes, such as Figure 2 As shown, the pressure-side ramp 56 and / or the suction-side ramp 58 may be generally flat surfaces (which can typically be planar or inclined). In other embodiments, such as Figure 3 As shown, the pressure-side inclined surface 56 and / or the suction-side inclined surface 58, or at least a portion thereof, may be curved planes. For example, the inclined surfaces 56 and / or 58 may be curved relative to the axial direction, the radial direction, and / or the tangential direction.

[0032] As described above, a plurality of rotor blades 30 may be disposed on each of one or more rotor disks 28 and may extend radially outward therefrom. The rotor blades 30 disposed on the rotor disks 28 may be assembled in a circumferential array such that when the rotor blades 30 are assembled in this manner, the pressure side slope 56 of each rotor blade 30 faces the suction side slope 58 of each adjacent rotor blade 30. Figure 4 A pair of circumferentially adjacent rotor blades 30' and 30'" are shown. As shown, when the rotor blades 30' and 30'" are positioned in this way, the pressure side slope 56 of the rotor blade 30'" faces the suction side slope 58 of the adjacent rotor blade 30'.

[0033] See now Figures 2 to 8One or more damper stacks 70 may be provided in a groove 60 in the rotor blade 30 according to the present disclosure. Specifically, the groove 60 may be defined in the inclined surfaces 56, 58 of the platform 42 of the rotor blade 30. The groove 60 may extend generally in the axial direction. The damper stacks 70 may be disposed in the groove 60, such as... Figure 2 and Figure 3 As shown. It is worth noting that, in an exemplary embodiment, the lateral portion of the damper stack 70 protrudes from the recess 60 such that, when assembled as described herein, the damper stack 70 also contacts the recess 60 defined in adjacent ramps 56, 58 of adjacent rotor blades 30.

[0034] Each damper stack 70 may be disposed within and in contact with the inclined surfaces 56, 58 (e.g., pressure-side inclined surface 56 or suction-side inclined surface 58) of the rotor blade 30, and may extend generally along the axial direction and thus generally along the length of the respective inclined surfaces 56, 58, as shown. Furthermore, as Figure 4 As shown, the damper stack 70 according to this disclosure can be disposed between and in contact with adjacent circumferentially adjacent rotor blades 30, facing the pressure-side inclined surface 56 or the suction-side inclined surface 58.

[0035] The damper stack 70 according to this disclosure is advantageously used as a vibration damper. In operation, the damper stack 70 frictionally dissipates vibrational energy and reduces the corresponding amplitude of the vibration. The amount of vibrational energy removed by the damper stack 70 is a function of several factors, including but not limited to the dynamic weight of the damper stack 70, the geometry of the stack 70, and the reactive load between adjacent rotor blades 30', 30"

[0036] Each damper stack 70 may include a plurality of damper pins 72 arranged end-to-end in a linear or curved shape corresponding to the groove 60. Each damper pin 72 may contact adjacent damper pins 72 in the damper stack 70. The use of the damper stack 70 according to this disclosure advantageously provides improved damping of the rotor blade 30 according to this disclosure. For example, the use of a plurality of discrete damper pins 72 in the arrangement shown and described herein advantageously provides improved damping over the entire length of the damper stack 70, due to the discrete motion that may be achieved by each damper pin 72 of the damper stack 70 within the groove 60 and by the simultaneous contact of the damper stack 70 with the groove 60 of the adjacent rotor blades 30', 30" of the adjacent rotor blades. In addition, such a damper stack 70 and its associated damper pins 72 may be adapted to the platform shape of complex planes, curved surfaces and / or partially curved surfaces.

[0037] See now for the appendix. Figures 5 to 8Various embodiments of a damper stack 70 according to this disclosure are shown. As discussed, the damper stack 70 includes a plurality of damper pins 72. Each damper pin 72 has a length 73 defined between a first end 74 and a second end 76 of the damper pin 72. The damper pins 72 may be arranged in a longitudinal linear array such that adjacent ends 74, 76 of adjacent damper pins 72 are in contact with each other.

[0038] For example, a plurality of damper pins 72 may include a first damper pin 72' and a second damper pin 72'", each of which extends between a first end 74 and a second end 76. The first end 74 of the first damper pin 72' may contact the second end 76 of the second damper pin 72'. In some embodiments, the second end 76 of the first damper pin 72' may contact another adjacent damper pin 72, and / or the first end 74 of the second damper pin 72' may contact another adjacent damper pin 72.

[0039] In addition to contacting the rotor blades 30', 30" in the contact with adjacent damper pins 72, the contact between them provides a significant damping mechanism for damping the rotor blades 30', 30" in the contact with the rotor blades. Therefore, the ends 74, 76 of adjacent damper pins 72 may have suitable shapes to provide such primary damping. In some embodiments, the contact ends 74, 76 of adjacent damper pins 72 may have complementary spherical shapes. For example, as... Figure 6 and Figure 7 As shown, the first end 74 of the first damper pin 72' may have an outward (convex) spherical shape, and the second end 76 of the second damper pin 72'" may have an inward (concave) spherical shape, or vice versa. In other embodiments, the contact ends 74, 76 of adjacent damper pins 72 may have mirror shapes. For example, as Figure 8 As shown, the first end 74 of the first damper pin 72' and the second end 76 of the second damper pin 72" can be flat surfaces adjacent to each other. Other suitable end shapes 74, 76 (such as conical, dome-shaped, or other complementary shapes) can be used, provided that such shapes provide suitable primary damping.

[0040] In some embodiments shown in the figure, the damper pin 72 may have a generally elliptical or rounded cross-sectional profile. Alternatively, other suitable cross-sectional profiles may be utilized. The cross-sectional profile may be constant or may vary along the length 73 of the damper pin 72. Furthermore, the damper pin 72 may have any suitable cross-sectional size. Additionally, the damper pin 72 may be formed of any suitable material. For multiple damper pins 72 in the damper stack 70, the shape, size, and / or material may be identical, or for one or more damper pins 72 within the damper stack 70, the shapes may vary.

[0041] As discussed, each of the plurality of damper pins 72 may have a length 73. In some embodiments, the length 73 of the damper pins 72 in the damper stack 70 may be the same. For example, as Figure 6 and Figure 8 As shown, the length 73 of the first damper pin 72' and the second damper pin 72" can be the same. In other embodiments, such as Figure 7 As shown, the length 73 of one or more damper pins 72 in the damper stack 70 may differ from that of the other damper pins 72 in the stack. For example, as Figure 7 As shown, the length 73 of the first damper pin 72' may be different from the length 73' of the second damper pin 72".

[0042] In an exemplary embodiment, each of the plurality of damper pins 72 has a hollow cross-sectional profile, such that it defines an internal channel 78 through the damper pin 72 and the damper stack 70. In other embodiments, the damper pins 72 and the damper stack 70 according to this disclosure may be solid, such that no internal channel is defined therethrough.

[0043] Additionally, in some embodiments as shown, wire 80 may extend through one or more damper pins 72 of the damper stack 70. For example, wire 80 may extend through an internal channel 78 or through a separately defined internal channel, leaving channel 78 empty. Wire 80 typically engages the damper pins 72 together. In other embodiments, other suitable components may be used to engage the damper pins 72 together, or the damper pins 72 may not be engaged together.

[0044] The damper stack 70 may include end pins 82, which are the outermost damper pins 72 on the respective ends of the damper stack 70. The end pins 82 are spaced apart from each other in the axial direction. As shown, the damper stack 70 includes a first end pin 82' spaced apart from a second end pin 82" in the axial direction. In some embodiments as shown, a cut-out portion 84 may be defined in each of these end pins 82', 82" such as in the outermost segment of the pin 82', 82" that includes the outermost end 74 or 76 (i.e., the end not adjacent to another pin 72). The cut-out portion 84 defines a shoulder 86 of the end pin 82', 82" . The shoulder 86 may include a support surface 88, which may be a flat planar surface in an exemplary embodiment.

[0045] In some embodiments, the recess 60 includes one or more shoulder slot portions 62, such as at respective ends of the recess 60. These portions 62 define a support surface 64, which in exemplary embodiments may be a flat planar surface. In these embodiments, shoulders 86 of end pins 82', 82" may be disposed in such shoulder slot portions 62 such that support surfaces 88 can contact support surfaces 64. Therefore, the damper stack 70 can be supported in the recess 60 and may reduce or prevent unwanted rotation during use and operation.

[0046] 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 methods. The patentable scope of the invention is defined by the claims, but may include other examples that would occur to a person skilled in the art. Such other examples are intended to be within the scope of the claims if they comprise structural elements that are not different from the literal language of the claims, or if they comprise equivalent structural elements that are not substantially different from the literal language of the claims.

Claims

1. A turbine, the turbine comprising: Compressor section (14); Burner section (16); Turbine section (18); A plurality of rotor blades (26, 30), the plurality of rotor blades being disposed in at least one of the compressor section (14) or the turbine section (18), each of the plurality of rotor blades (26, 30) comprising: The main body includes a handle (38) and a wing (36) extending radially outward from the handle (38). Platform (42), the platform surrounding the body, the platform (42) including inclined planes (56, 58); and A damper stack (70) is disposed on the inclined planes (56, 58) and extends generally in the axial direction. The damper stack (70) includes a plurality of damper pins (72), each of the plurality of damper pins (72) contacting an adjacent damper pin (72). Each of the plurality of damper pins extends between a first end and a second end. A first end of a first damper pin defines a spherical convex shape, and a second end of a second damper pin defines a spherical concave shape, the second end of the second damper pin engaging with the first end of the first damper pin.

2. The turbine according to claim 1, wherein each of the plurality of damper pins (72) extends between the first end (74) having the convex shape and the second end (76) having the concave shape.

3. The turbine according to claim 2, wherein the first end (74) of the first damper pin (72') has an outward spherical shape, and the second end (76) of the second damper pin (72") has an inward spherical shape.

4. The turbine according to any one of claims 2 to 3, wherein the length (73) of each of the plurality of damper pins (72) is defined between the first end (74) and the second end (76) of the damper pin, and wherein the length (73) of one of the plurality of damper pins is different from the length (73) of another of the plurality of damper pins.

5. The turbine according to any one of claims 1 to 4, wherein the damper stack (70) further comprises a wire (80) extending through each of the plurality of damper pins (72).

6. The turbine according to any one of claims 1 to 5, wherein the groove (60) is defined in the inclined surface (56, 58), and wherein the damper stack (70) is partially disposed in the groove (60).

7. The turbine according to any one of claims 1 to 6, wherein the plurality of damper pins (72) includes a first end pin (82') and a second end pin (82"), the first end pin (82') and the second end pin (82") being spaced apart in the axial direction, the first end pin (82') and the second end pin (82') each including a shoulder (86) defined by a cutout portion (84).

8. The turbine of claim 7, wherein each of the shoulders (86) comprises a flat support surface (64).

9. The turbine according to any one of claims 7 to 8, wherein the groove (60) is defined in the inclined surface, wherein the damper stack (70) is partially disposed in the groove (60), and wherein each of the shoulders (86) is disposed in a shoulder slot portion (62) of the groove (60).

10. The turbine according to any one of claims 1 to 9, wherein the plurality of rotor blades (30) are disposed in the turbine section (18).

11. The turbine according to any one of claims 1 to 10, wherein the turbine is a gas turbine (10).

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