Damping device for damping shaft vibrations

Abstract

A damping device, a turbine and a method for damping vibrations are provided. For example, a damping device for damping vibrations of a shaft rotatable about a rotation axis is provided. The damping device defines a radial direction and an axial direction. The damping device includes a bearing, a housing and a damper element. The housing and the damper element define a cavity for receiving a damping fluid therebetween. The cavity has a length that is bent away from the rotation axis along the axial direction. As another example, a turbine including a shaft rotatable about a rotation axis includes a damping device positioned annularly around the shaft. The damping device includes a housing and a damper element, the housing and the damper element defining a cavity therebetween for receiving a damping fluid having a curved shape. The cavity is bent in a plane extending in a radial direction and an axial direction and including the rotation axis.

Description

Technical Field

[0001] The present subject matter generally relates to damping devices for damping shaft vibrations. Background Art

[0002] Many turbine engines contain squeeze film damper (SFD) devices that damp radial vibrations caused by relative radial motion between the rotor and the support structure. The SFD is typically mounted around one or more rotor bearings and has a cylindrical fluid film that moves under radial loads from the bearings. Therefore, axial damping is typically formed independently of radial damping, requiring larger or additional dampers for effective axial, radial, and rotational damping. In addition, typical dampers may provide ineffective damping in the axial and rotational directions, which may lead to rotor instability, reduced engine performance, and component damage. Therefore, a damping device that addresses one or more of the above challenges would be useful. In particular, a damping device that includes features for damping rotor vibrations of a turbine in radial, axial, and rotational directions in a single device would be desirable. Summary of the invention

[0003] Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0004] In an exemplary embodiment of the present subject matter, a turbine is provided. The turbine includes a shaft rotatable about a rotation axis and a damping device annularly positioned about the shaft. The damping device defines a radial direction and an axial direction; the axial direction is parallel to the rotation axis. The damping device includes a bearing operably coupled to the shaft, a housing, and a damper element. The housing and the damper element define a cavity therebetween for receiving a damping fluid. The cavity has a curved shape. The shaft extends longitudinally along the axial direction, and the cavity is curved in a plane extending along the radial direction and the axial direction and including the rotation axis.

[0005] In another exemplary embodiment of the present subject matter, a damping device for damping vibrations of a shaft rotatable about a rotation axis is provided. The damping device defines a radial direction and an axial direction; the axial direction is parallel to the rotation axis. The damping device includes a bearing, a housing, and a damper element. The housing and the damper element define a cavity therebetween for receiving a damping fluid. The cavity has a length along the axial direction, and the length of the cavity curves away from the rotation axis.

[0006] In another exemplary embodiment of the present subject matter, a method of damping vibrations of a shaft is provided. The method includes rotating the shaft about an axis of rotation; damping axial vibrations of the shaft by a damping device; and damping a tipping moment of the shaft by the damping device. The damping device defines a radial direction and an axial direction. The axial direction is parallel to the axis of rotation so that the shaft extends longitudinally in the axial direction. The damping device includes a bearing, a housing, and a damper element. The housing and the damper element define a cavity therebetween for receiving a damping fluid. The cavity has a curved shape and is curved in a plane extending along the radial direction and the axial direction and including the axis of rotation.

[0007] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims.The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] This specification sets forth a complete and enabling disclosure of the present invention, including the best mode thereof, to one of ordinary skill in the art with reference to the accompanying drawings, in which:

[0009] Figure 1 Schematic cross-sectional views of exemplary gas turbine engines are provided according to various embodiments of the present subject matter.

[0010] Figure 2 A cross-sectional view of a damping device according to an exemplary embodiment of the present subject matter is provided.

[0011] Figure 3 A cross-sectional view of a damping device according to another exemplary embodiment of the present subject matter is provided.

[0012] 4 provides a schematic cross-sectional view of a prior art damping fluid film that is linear in a plane defined by radial and axial directions and includes the axis of rotation of a shaft that is damped by the damping fluid film.

[0013] Figure 5 A schematic cross-sectional view of a damping fluid film of the subject invention is provided, the damping fluid film being curved within a plane defined by radial and axial directions and including the axis of rotation of a shaft damped by the damping fluid film.

[0014] Figure 6 A flow chart is provided that illustrates a method of damping vibrations of a shaft according to an exemplary embodiment of the present subject matter. DETAILED DESCRIPTION

[0015] Reference will now be made in detail to the present embodiments of the invention, one or more examples of which are shown in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and the specification are used to refer to like or similar parts of the invention.

[0016] As used herein, the terms "first", "second", and "third" are used interchangeably to distinguish one component from another, and are not intended to indicate the location or importance of a single component. The terms "forward" and "rearward" refer to relative positions within a gas turbine engine or vehicle, and refer to the normal operating posture of the gas turbine engine or vehicle. For example, for a gas turbine engine, forward refers to a position closer to the engine inlet, and rearward refers to a position closer to the engine nozzle or exhaust. The terms "upstream" and "downstream" refer to the relative direction of the flow of a fluid relative to a fluid path. For example, "upstream" refers to the direction from which the fluid flows, and "downstream" refers to the direction to which the fluid flows. Unless otherwise specified herein, the terms "connected", "fixed", "attached", etc. refer to direct connection, fixation or attachment, as well as indirect connection, fixation or attachment through one or more intermediate components or features. Unless the context clearly dictates otherwise, the singular forms "one", "an", and "the" include plural references.

[0017] In addition, as used herein, the term "axial" or "axially" refers to the dimension along the longitudinal axis of the engine. The term "forward" used with "axial" or "axially" refers to the direction toward the engine inlet, or a component that is relatively closer to the engine inlet than another component. The term "rearward" or "rear" used with "axial" or "axially" refers to the direction toward the engine exhaust, or a component that is relatively closer to the engine exhaust than another component. The term "radial" or "radially" refers to the dimension extending between the central longitudinal axis (or centerline) of the engine and the outer circumference of the engine. Radially inward is toward the longitudinal axis, and radially outward is away from the longitudinal axis.

[0018] Approximate language used in this specification and claims is used to modify any quantitative representation that can be allowed to vary without causing a change in the basic function associated with it. Therefore, values ​​modified by one or more terms, such as "approximately", "approximately" and "substantially" are not limited to the precise values ​​specified. In at least some instances, approximate language may correspond to the accuracy of an instrument used to measure a value, or the accuracy of a method or machine used to build or manufacture a component and / or system. Approximate language can refer to within + / -1%, 2%, 4%, 10%, 15% or 20% of a single value, a range of values, and / or an endpoint defining a range of values.

[0019] Here and throughout the specification and claims, range limitations are combined and interchanged, and unless context or language indicates otherwise, these ranges are identified and include all sub-ranges contained therein. For example, all ranges disclosed herein include the endpoints, and the endpoints are independently combinable with each other.

[0020] Generally, the present subject matter relates to a damping device for damping shaft vibrations. More specifically, the present subject matter relates to a damping device for damping vibrations of a shaft rotatable about an axis of rotation, wherein the damping device includes a cavity for receiving a damping fluid such that a fluid film formed by the damping fluid is non-cylindrical. For example, the cavity is curved in a plane extending along a radial direction and an axial direction defined by the damping device and including the axis of rotation. In addition, the cavity can have a length extending parallel to the axis of rotation, and the cavity can be curved such that the length is curved away from the axis of rotation. The curved fluid film produced by the curved cavity of the damping device can provide moment or rotational damping as well as radial and axial damping. A turbine including such a damping device and a method of damping shaft vibrations are also provided.

[0021] Referring now to the drawings, wherein like numerals refer to like elements throughout, Figure 1 is a schematic cross-sectional view of a gas turbine engine according to an exemplary embodiment of the present disclosure. More specifically, Figure 1 In the embodiment of the present invention, the gas turbine engine is a high bypass turbofan jet engine 10, referred to herein as a "turbofan engine 10". Figure 1 As shown, the turbofan engine 10 defines an axial direction A (extending parallel to a longitudinal centerline 12 provided for reference), a circumferential direction C (extending about the longitudinal centerline 12 and the axial direction A), and a radial direction R. Generally, the turbofan 10 includes a fan section 14 and a core turbine engine 16 disposed downstream of the fan section 14 .

[0022] The depicted exemplary core turbine engine 16 generally includes a substantially tubular outer casing 18 defining an annular inlet 20. The outer casing 18 surrounds in series flow relationship a compressor section including a supercharger or low pressure (LP) compressor 22 and a high pressure (HP) compressor 24; a combustion section 26; a turbine section including a high pressure (HP) turbine 28 and a low pressure (LP) turbine 30; and an ejection exhaust nozzle section 32. A high pressure (HP) shaft or valve core 34 drivingly connects the HP turbine 28 to the HP compressor 24. A low pressure (LP) shaft or valve core 36 drivingly connects the LP turbine 30 to the LP compressor 22.

[0023] For the depicted embodiment, fan section 14 includes a fan 38 having a plurality of fan blades 40 coupled in a spaced-apart manner to a disk or hub 42. As shown, fan blades 40 extend outwardly from disk 42 generally in a radial direction R. Fan blades 40 and disk 42 may rotate together about longitudinal centerline 12 via LP shaft 36. In some embodiments, a power gearbox having a plurality of gears may be included for reducing the rotational speed of LP shaft 36 to a more efficient rotational fan speed.

[0024] Still refer to Figure 1 In an exemplary embodiment of the present invention, the disk 42 is covered by a rotatable forward nacelle 48 having an aerodynamic profile to facilitate airflow through the plurality of fan blades 40. In addition, the exemplary fan section 14 includes an annular fan case or outer nacelle 50 that circumferentially surrounds the fan 38 and / or at least a portion of the core turbine engine 16. It should be understood that the fan case (nacelle) 50 may be configured to be supported relative to the core turbine engine 16 by a plurality of circumferentially spaced outlet guide vanes 52. In addition, a downstream portion 54 of the fan case 50 may extend above the exterior of the core turbine engine 16 to define a bypass airflow passage 56 therebetween.

[0025] During operation of the turbofan engine 10, a volume of air 58 enters the turbofan 10 through the fan case 50 and / or the associated inlet 60 of the fan section 14. As the volume of air 58 passes through the fan blades 40, a first portion of the air 58, as indicated by arrow 62, is directed or delivered into the bypass airflow passage 56, and a second portion of the air 58, as indicated by arrow 64, is directed or delivered into the LP compressor 22. The ratio between the first portion of air 62 and the second portion of air 64 is generally referred to as the bypass ratio. The second portion of air 64 then increases in pressure as it is delivered through the compressor section into the combustion section 26, where it is mixed with fuel and combusted to provide combustion gases 66. More specifically, the compressor section includes an LP compressor 22 and an HP compressor 24, each of which may include a plurality of compressor stages 80, each stage 80 including an annular array or circumferential row of stationary compressor blades 82 (also referred to as compressor stator blades 82) and an annular array or circumferential row of rotating compressor blades 84 (also referred to as compressor rotor blades 84) located immediately downstream of the compressor blades 82. The plurality of compressor blades 84 in the LP compressor 22 are coupled to the LP shaft or valve core 36, and the plurality of compressor blades in the HP compressor 24 are coupled to the HP shaft or valve core 34. The plurality of compressor blades 82 in the LP compressor 22 are coupled to a compressor casing, and the plurality of compressor blades 82 in the HP compressor 24 are coupled to a compressor casing; at least a portion of the HP compressor blade blades are connected to a compressor casing 90. In some embodiments, the compressor casing 90 may extend through both the LP compressor 22 and the HP compressor 24 and support all of the compressor blades 82. In other embodiments, the compressor casing 90 supports only a portion of the compressor blades 82, and may support only a portion of the compressor blades 82 in the HP compressor 24. As previously described, as the second portion of air 64 passes through successive stages of compressor buckets 82 and blades 84 , the volume of air 64 is pressurized, ie, the pressure of air 64 is increased prior to combusting with fuel in the combustion section 26 to form combustion gases 66 .

[0026] The combustion gases 66 are routed through the HP turbine 28, wherein a portion of the heat and / or kinetic energy is extracted from the combustion gases 66 by successive stages of HP turbine stator vanes 68 connected to the casing 18 and HP turbine rotor blades 70 connected to the HP shaft or spool 34, thereby rotating the HP shaft or spool 34 to support operation of the HP compressor 24. The combustion gases 66 are then routed through the LP turbine 30, wherein a second portion of the heat and kinetic energy is extracted from the combustion gases 66 by successive stages of LP turbine stator vanes 72 connected to the casing 18 and LP turbine rotor blades 74 connected to the LP shaft or spool 36, thereby rotating the LP shaft or spool 36 to support operation of the LP compressor 22 and / or rotation of the fan 38.

[0027] The combustion gases 66 are then routed through the jet exhaust nozzle section 32 of the core turbine engine 16 to provide propulsive thrust. At the same time, the pressure of the first portion of air 62 is significantly increased as the first portion of air 62 is routed through the bypass airflow passage 56 before being discharged from the fan nozzle exhaust portion 76 of the turbine fan 10, also providing propulsive thrust. The HP turbine 28, the LP turbine 30, and the jet exhaust nozzle section 32 at least partially define a hot gas path 78 for routing the combustion gases 66 through the core turbine engine 16.

[0028] Although Figure 1 The gas turbine engine of FIG. 1 is depicted as a turboshaft configuration, but it should be understood that the teachings of the present disclosure may be applied to other types of turbine engines, more general turbomachines, and other shaft systems. For example, the turbine engine may be another suitable type of gas turbine engine, such as a turboprop engine, a turbojet engine, a turbofan engine, an aeroderivative engine, etc. The present invention is also applicable to other types of turbomachinery, such as steam turbine engines and centrifugal pumps. The present disclosure may also be applied to other types of shaft systems, such as a tail rotor drive shaft of a rotating aircraft (e.g., a helicopter).

[0029] Figure 2 A schematic cross-sectional view of a damping device 100 according to an exemplary embodiment of the present subject matter is provided. Figure 3 A schematic cross-sectional view of a damping device 100 according to another exemplary embodiment of the present subject matter is provided. Figure 2 and Figure 3 The damping device 100 may be used to damp shaft vibrations of one or more shafts of any suitable turbine, drive system, or any suitable shaft system. As an example, the damping device 100 may be operably configured to damp Figure 1 As another example, damping device 100 may be operably configured to damp axial vibrations of one or more shafts of gas turbine engine 10. As another example, damping device 100 may be operably configured to damp axial vibrations of a drive shaft of a transmission system (e.g., a tail rotor drive shaft of a rotary aircraft). As yet another example, damping device 100 may be operably configured to damp axial vibrations of a counter-rotating bladeless gas turbine engine (i.e., a gas turbine engine having a counter-rotating drum to which blades are attached that are interdigitated with blades of an inner rotor, rather than having an annular array of axially spaced stator vanes). Other applications are possible.

[0030] like Figure 2 and Figure 3As shown in each of the drawings, the damping device 100 defines an axial direction A, a radial direction R, and a circumferential direction C, which, in the exemplary embodiment, correspond to the axial, radial, and circumferential directions A, R, C of the engine 10. The shaft 102 extends through the damping device 100 so that the damping device 100 is positioned annularly around the shaft 102. In addition, the shaft 102 extends longitudinally along the axial direction A and is rotatable around the rotation axis AX. The axial direction A extends parallel to the rotation axis AX, the radial direction R extends to and from the rotation axis AX in a direction orthogonal to the axial direction A, and the circumferential direction C extends 360 degrees (360°) around the rotation axis AX. In an embodiment where the damping device 100 is used for a turbine (e.g., the engine 10), the rotation axis AX may be the centerline axis 12 of the engine 10, or may be parallel to the engine centerline axis.

[0031] like Figure 2 and Figure 3 As further shown, each exemplary damping device 100 includes a bearing 104 operably coupled to the shaft 102, a housing 106, and a damper element 108. The housing 106 and the damper element 108 are positioned between a support structure 110 and the bearing 104, such as along a radial direction R. More specifically, each of the housing 106 and the damper element 108 extends annularly or circumferentially around the shaft 102 and the bearing 104, and the housing also extends annularly or circumferentially around the damper element 108. The support structure 110 may be any suitable structure, such as a strut or a housing.

[0032] and Figure 2 and 3 In keeping with the above, the housing 106 and the damper element 108 of each exemplary damping device 100 define therebetween a damping fluid F ( Figure 5 ) of the cavity 112. The cavity 112 has a curved shape. More specifically, each of the housing 106 and the damper element 108 is curved in complementary directions to define the curved shape of the cavity 112. Figure 2 In an exemplary embodiment of the present invention, the damper element 108 is bent away from the rotation axis AX, so that the damper element 108 has a convex curved shape. Figure 3 In the exemplary embodiments of the present invention, the damper element 108 is curved toward the rotation axis AX, so that the damper element 108 has a concave curved shape. In each of the illustrated exemplary embodiments, the cavity 112 is curved in a plane P extending in the radial direction R and the axial direction A and including the rotation axis AX. Furthermore, in each of these exemplary embodiments, the cross-section of the curved shape is a semicircle, but other cross-sectional shapes and curved shapes may also be used to define a non-linear fluid film parallel to the rotation axis.

[0033] like Figure 5As shown, when the damping fluid F is received in the cavity 112, the damping fluid F provides a fluid film having a curved shape of the cavity 112 for damping the shaft vibration. In addition, the fluid film formed by the damping fluid F has a fluid film length L extending along the axial direction A or parallel to the rotation axis AX. f .like Figure 5 As shown, the length L f The angle of the curved shape is measured from a first position (1) to a second position (2), wherein the second position (2) is spaced apart from the first position (1) along the axial direction A. Figure 2 , 3 5, the length L of the cavity 112 and the damping fluid film F f Bends away from the axis of rotation AX.

[0034] Furthermore, the cavity 112 and the membrane of the damping fluid F have a radius of curvature r CURVE , and the fluid film length Lf can be the radius of curvature r CURVE For example, for a function with Figure 2 , 3 For a fluid film with a semicircular cross section as shown in Figure 5, the length Lf is the circumference or arc length of the semicircle:

[0035] L f =πr curve

[0036] The radius or average radius of the fluid film and the length L of the fluid film f Determines the contact surface area of ​​the film of damping fluid F. Comparing Figure 4 with Figure 5 In comparison, FIG. 4 shows a known or prior art fluid film that is rectilinear in plane P and has a film thickness c, Figure 5 The curved fluid film of the present subject matter also has a film thickness c, which has a larger contact surface area than the straight fluid film of the prior art. More specifically, having an axial length L art The straight fluid film has a contact surface area smaller than the contact surface area of ​​the curved fluid film, which is determined by the curvature radius r of the curved film of the damping fluid F. CURVE and length L f Therefore, the prior art straight fluid membrane provides less damping than the curved fluid membrane of the present subject matter. Therefore, a smaller damping device 100 can be used to provide equivalent damping to a prior art damper such as that shown in FIG. 4 , which can facilitate a more compact damper.

[0037] Furthermore, the amount of damping provided by the curved fluid film can be varied between exemplary damping devices 100, for example by varying the radius of curvature r of the damping device 100. CURVEMore specifically, the amount of curvature is proportional to the amount of damping, such that when the radius of curvature r of the damping fluid film of the first damping device 100 is CURVE is greater than the curvature radius r of the damping fluid film of the second damping device 100 CURVE , the first damping device 100 provides greater damping than the second damping device 100. Therefore, the larger radius of curvature r CURVE The damping device 100 has a smaller curvature radius r than CURVE The damping device 100 provides greater or more damping, whereas the damping device 100 having a smaller radius of curvature r CURVE The damping device 100 has a larger curvature radius r than CURVE The damping device 100 provides less damping.

[0038] As shown in FIG. 4 , the geometric center of the linear fluid film of the prior art is defined as a radial distance or radius r from the rotation axis AX. Center At , the rotation axis AX may be an engine centerline axis (eg, centerline axis 12) in a turbine engine such as engine 10 in which an embodiment of the damping device 100 is used. Figure 5 As shown, the geometric center of the curved fluid film is defined at a radial distance or radius r from the rotation axis AX. Center As shown in Figure 4 and Figure 5 As shown in comparison, the curved fluid film of the present subject matter is at two locations spaced apart from each other along the axial direction A and at a radius r drawn to the geometric center of the curved film. Center In contrast, the straight fluid film is along the entire axial length L of the straight fluid film. art with the radius r drawn to the geometric center of the straight line membrane Center Center intersection.

[0039] It should be understood that the prior art fluid film is referred to as "straight" because it has a straight cross-section in a plane P extending along the radial direction R and the axial direction A and including the rotation axis AX. In addition, the prior art fluid film is cylindrical, extending longitudinally parallel to the rotation axis AX, so that the prior art fluid film circumferentially surrounds the rotation axis AX. As described herein, the damping device 100 produces a curved fluid film in the plane P that has a curved (e.g., semicircular) cross-sectional shape and is non-cylindrical.

[0040] It should be understood that in embodiments where the curved shape is a semicircle, each of the upper and lower cross-sections of the fluid cavity 112 and the damping fluid membrane is a semicircle. Figure 5 Shows Figure 2 The damping fluid fills the upper cross section of the cavity 112. That is, referring to Figure 2In the cross-sectional view of the embodiment of the present invention, the upper cross-section of the damping device 100 is shown above the rotation axis AX, and the lower cross-section of the damping device 100 is shown below the rotation axis AX, wherein "above" and "below" the rotation axis represent relative vertical positions relative to the page. In other embodiments, the cavity 112 may have other curved shapes.

[0041] In addition, see Figure 2 and 3 , the upper part of the damping device 100 works against the lower part of the damping device 100. Therefore, the film of the damping fluid F is squeezed in opposite directions, providing axial damping. In addition, because the damping fluid film is curved, it is squeezed in both the axial direction A and the radial direction R, which provides overturning moment (OTM) damping. Therefore, unlike conventional dampers that only provide radial damping or only provide axial damping, the damping device 100 provides axial and moment damping; moment damping may also be referred to as rotational damping. Such axial and moment damping is particularly useful for bearing arrangements that can withstand moment loads. In addition, the damping device 100 described herein is a radially and axially cross-coupled damper that improves the stability margin by providing additional stator damping in addition to the radial degree of freedom.

[0042] like Figure 2 and Figure 3 As shown, the damping device 100 defines a fluid inlet 114 for the damping fluid F to enter the cavity 112. It should be understood that Figure 2 and Figure 3 The semicircular cross-sectional shape of the hollow cavity 112 may also be described as a parabola or parabola shape, such that the cavity 112 has a vertex 116 that passes through the axis of symmetry of the parabola. Figure 2 As shown, for a convex parabolic cavity 112, the fluid inlet 114 may be defined radially outward of the apex 116. Figure 3 As shown, for the concave parabolic cavity 112, the fluid inlet 114 is defined radially inward of the vertex 116. It should be understood that the damping device 100 may further define a fluid outlet (not shown) for exhausting the damping fluid F from the cavity 112. For example, during operation, the damping fluid F may be circulated through the cavity 112 via a circulation system, for example, to introduce relatively cool damping fluid into the cavity 112 and remove relatively hot damping fluid from the cavity 112. The relatively cool damping fluid F may enter the cavity 112 through the fluid inlet 114 and may exit the cavity 112 through the fluid outlet.

[0043] In the exemplary embodiment, damping device 100 also includes a support arm 118 for evenly distributing damping fluid F within cavity 112. More specifically, support arm 118 helps position damping device 100 relative to shaft 102 to provide a uniform film of damping fluid F along the circumference of damper element 108. A centering spring or other biasing mechanism may be used with support arm 118 to adjust the position of damping device 100 and thereby control the uniformity of the damping fluid film.

[0044] and Figure 2 and Figure 3 In accordance with the present invention, the bearing 104 includes an inner race 104A and an outer race 104B. As shown in the exemplary embodiment depicted, the support arm 118 can be disposed between the damper element 108 and the outer race 104B of the bearing 104. In addition, the inner race 104A can be coupled to the shaft 102 and the outer race 104B can be coupled to the damper element 108.

[0045] In the exemplary embodiment, bearing 104 is a dual roller element bearing having two rows of roller elements 120. In other embodiments, bearing 104 may be a single roller element bearing having a single row of roller elements 120, or bearing 104 may have any other number of rows of roller elements 120. Furthermore, roller elements 120 may be balls, such that bearing 104 is a ball roller bearing; tapered rollers, such that bearing 104 is a tapered roller bearing; or any other suitable roller elements.

[0046] like Figure 2 and Figure 3 As further shown, the damping device 100 has a first end 122 and a second end 124. In an exemplary embodiment, the damping device 100 includes a first end seal 126 on the first end 122 between the housing 106 and the bearing 104 and a second end seal 128 on the second end 124 between the housing 106 and the bearing 104. That is, the end seals 126, 128 are configured to prevent the damping fluid F from leaking from the damping device 100, wherein the first end seal 126 seals the cavity 112 on the first end 122 of the damping device 100, and the second end seal 128 seals the cavity 112 on the second end 124 of the damping device 100, and the second end 124 is axially opposite to the first end 122.

[0047] This topic also provides various damping methods, such as methods for damping moments on an axis. Figure 6, an exemplary method 600 of damping vibrations on a shaft (e.g., shaft 102) is shown. The exemplary method 600 includes rotating the shaft 102 about a rotation axis AX at 602. The exemplary method 600 also includes damping axial vibrations of the shaft 102 via the damping device 100 and damping an overturning moment of the shaft 102 via the damping device 100 at 604 and 606, respectively. Thus, both axial and moment (or rotational) damping are provided by a single damping device 100.

[0048] As described herein, the damping device 100 provides a non-cylindrical damping fluid film that is bent in a plane P extending along a radial direction R and an axial direction A defined by the damping device 100 and including the rotation axis of the shaft 102, the vibration of which is damped by the damping device 100. More specifically, the damping device 100 includes a housing 106 and a damper element 108 that are complementarily bent to define a curved cavity 112 therebetween, and a damping fluid F is contained in the curved cavity 112. The housing 106 and the damper element 108 both circumferentially surround a bearing 104 that is operably coupled to the shaft 102; the damper element 108 is coupled to the bearing 104. Therefore, the shaft vibration and damping provided by the damping fluid F are transmitted through the bearing 104. As described herein, the non-cylindrical nature of the damping fluid film provides damping in more than one degree of freedom, namely, damping of axial and moment or bending vibrations (e.g., by allowing axial and radial squeezing of the bending fluid film, which results in overturning moment (OTM) damping), unlike conventional cylindrical damping fluid films that only provide damping in one degree of freedom.

[0049] Thus, the present subject matter relates to a damper device that provides damping in radial, axial, and rotational directions in a single device. More specifically, the damper device described herein provides a non-cylindrical fluid film between the inner and outer races of a bearing that provides radial and axial damping as well as moment damping when required. As described herein, providing radial and axial damping within the same damper allows for cross-linked damping that provides overturning moment (OTM) damping on a rotor supported by the bearing. For example, the damper device described herein allows for bending or axial and radial squeezing of the damping fluid supply, which results in overturning moment damping. Thus, the fluid film provides additional stator damping (rotational and axial damping), which improves the stability of the rotor because the additional stator damping in addition to the radial direction helps to improve the stability margin. In addition, the circumferential or curved fluid film provided by the damper of the present subject matter has a larger effective length and a larger average film radius than the linear fluid film of a conventional damper, which increases damping within the same geometry (i.e., the damper of the present invention increases damping compared to a conventional damper of the same size). Therefore, compared to conventional dampers, the damping device described herein can have a compact design (i.e., the damper size can be reduced without reducing damping performance) while providing benefits such as OTM damping and improved stability. More compact dampers can be used in certain applications, such as counter-rotating gas turbine engines. In addition, since smaller and / or fewer dampers can be used without compromising damping performance, the present subject matter allows gas turbine engines equipped with such dampers to reduce vibration, reduce loads, and save weight / cost. Reducing the engine weight of an aircraft engine helps the aircraft save fuel, i.e., the aircraft has reduced fuel consumption. Other benefits and advantages of the present subject matter can also be achieved.

[0050] Further aspects of the invention are provided by the subject matter of the following clauses:

[0051] 1. A turbine, comprising a shaft rotatable about a rotation axis; and a damping device, the damping device being positioned around the shaft, the damping device defining a radial direction and an axial direction, the axial direction being parallel to the rotation axis, the damping device comprising a bearing operably coupled to the shaft, a housing and a damper element, the housing and the damper element defining between them a cavity for receiving a damping fluid, the cavity having a curved shape, wherein the shaft extends longitudinally along the axial direction, and wherein the cavity is curved in a plane extending along the radial direction and the axial direction and including the rotation axis.

[0052] 2. A turbine according to any preceding clause, wherein the cross-section of the curved shape has a radius of curvature, and wherein the length of the cross-section of the curved shape is a function of the radius of curvature, the length being measured along the curved shape from a first position to a second position, the second position being spaced apart from the first position along the axial direction.

[0053] 3. A turbine as claimed in any preceding clause, wherein said curved shape is semi-circular.

[0054] 4. A turbine according to any preceding clause, wherein each of the housing and the damper element is curved in complementary directions to define the curved shape of the cavity, and wherein the damper element is curved away from the axis of rotation so that the damper element has a convex curved shape.

[0055] 5. A turbine according to any preceding clause, wherein the damping arrangement further comprises a fluid inlet for the damping fluid to enter the cavity, wherein the shape of the cross-section of the damper element is a parabola, and wherein the fluid inlet is defined radially outwardly of a vertex of the cross-section.

[0056] 6. A turbine according to any preceding clause, wherein each of the housing and the damper element is curved in complementary directions to define the curved shape of the cavity, and wherein the damper element is curved towards the axis of rotation so that the damper element has a concave curved shape.

[0057] 7. A turbine according to any preceding clause, wherein the damping arrangement further comprises a fluid inlet for the damping fluid to enter the cavity, wherein the shape of the cross-section of the damper element is a parabola, and wherein the fluid inlet is defined radially inwardly of the apex of the cross-section.

[0058] 8. A turbine according to any preceding clause, wherein the damping device further comprises a compression arm for evenly distributing the damping fluid within the cavity.

[0059] 9. A turbine according to any preceding clause, wherein the bearing comprises an inner race and an outer race, and wherein the compression arm is provided between the damper element and the outer race.

[0060] 10. The turbine of any preceding clause, wherein the bearing comprises an inner race and an outer race, and wherein the outer race is coupled to the damper element.

[0061] 11. A turbine according to any preceding clause, wherein said housing circumferentially surrounds said damper element and said bearing.

[0062] 12. A turbine according to any preceding clause, wherein the damping device has a first end and a second end, the second end being axially opposite the first end, and wherein the damping device further comprises a first end seal on the first end between the housing and the bearing, and a second end seal on the second end between the housing and the bearing.

[0063] 13. A turbine as claimed in any preceding clause wherein said bearing is a ball roller bearing.

[0064] 14. A turbine as claimed in any preceding clause wherein the bearing is a tapered roller bearing.

[0065] 15. A turbine as claimed in any preceding clause, wherein the bearing is a duplex bearing.

[0066] 16. A damping device for damping vibrations of a shaft rotatable about a rotation axis, the damping device defining a radial direction and an axial direction, the axial direction being parallel to the rotation axis, the damping device comprising a bearing; a housing; and a damper element, the housing and the damper element defining a cavity between the housing and the damper element for receiving a damping fluid, the cavity having a length along an axial direction, wherein the length of the cavity is bent away from the rotation axis.

[0067] 17. A damping device according to any preceding clause, said length being curved in a plane extending along said radial direction and said axial direction and including said axis of rotation.

[0068] 18. A damping device according to any preceding clause, wherein the bearing comprises an inner race and an outer race, wherein the outer race is coupled to the damper element, wherein the damping device has an upstream end and a downstream end, wherein the damping device further comprises a compression arm for evenly distributing the damping fluid within the cavity, a first end seal on the upstream end between the housing and the bearing, and a second end seal on the downstream end between the housing and the bearing, and wherein the compression arm is disposed between the damper element and the outer race.

[0069] 19. A damping device according to any preceding clause, wherein the bearing is a roller bearing.

[0070] 20. A damping device as claimed in any preceding clause, wherein the damping device provides damping in more than one degree of freedom.

[0071] 21. A method for damping shaft vibration, the method comprising: rotating the shaft around a rotation axis; damping axial vibration of the shaft by a damping device; and damping the overturning moment of the shaft by the damping device, wherein the damping device defines a radial direction and an axial direction, the axial direction is parallel to the rotation axis, so that the shaft extends longitudinally along the axial direction, wherein the damping device includes a bearing, a housing and a damper element operably connected to the shaft, the housing and the damper element define a cavity therebetween for receiving a damping fluid, the cavity having a curved shape, wherein the cavity is curved in a plane extending along the radial direction and the axial direction and including the rotation axis.

[0072] 22. The method of any preceding clause, wherein the housing and the damper element are complementarily curved to define a curved cavity therebetween.

[0073] 23. The method of any preceding clause, wherein the housing and the damper element each circumferentially surround the bearing.

[0074] 24. The method of any preceding clause, wherein the damper element is coupled to the bearing.

[0075] 25. The method of any preceding clause, wherein the cavity is non-cylindrical in shape.

[0076] 26. The method of any preceding clause, wherein the curved shape is a semicircle.

[0077] 27. The method of any preceding clause, wherein the damping fluid assumes a curved shape of the cavity, and wherein damping axial vibrations and overturning moments of the shaft via the damping device comprises axial and radial compression of a curved fluid film.

[0078] This written description uses examples to disclose the invention, including the best mode, and also to enable those skilled in the art to practice the invention, including making and using any devices or systems and performing any combined methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. These other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ much from the literal language of the claims.

Claims

1. A turbine, characterized in that: include: A shaft capable of rotating about an axis of rotation; and a damping device positioned around the shaft, the damping device defining a radial direction and an axial direction, the axial direction being parallel to the axis of rotation, the damping device comprising: a bearing operably coupled to the shaft, case, a damper element, the housing and the damper element being of complementary non-linear shapes to define a cavity therebetween for receiving a damping fluid, the cavity having a curved shape, and the cavity having a semi-circular shape and an arcuate portion extending radially inwardly, and a support structure, wherein the housing is located between the support structure and the damper element; wherein the shaft extends longitudinally along the axial direction, and Therein, the cavity is curved in a plane extending along the radial direction and the axial direction and including the rotation axis.

2. The turbine according to claim 1, characterized in that wherein the cross-section of the curved shape has a radius of curvature, and wherein a length of the cross-section of the curved shape is a function of the radius of curvature, the length being measured from a first position to a second position along the curved shape, the second position being spaced apart from the first position along the axial direction.

3. The turbine according to claim 1, characterized in that Wherein the curved shape is a semicircle.

4. The turbine according to claim 1, characterized in that wherein each of the housing and the damper element is curved in complementary directions to define the curved shape of the cavity, and wherein the damper element is curved away from the rotational axis such that the damper element has a convex curved shape.

5. The turbine according to claim 4, characterized in that in, The damping device further comprises a fluid inlet for the damping fluid to enter the cavity, wherein the shape of the cross-section of the damper element is a parabola, and wherein the fluid inlet is defined radially outwardly of a vertex of the cross-section.

6. The turbine according to claim 1, characterized in that wherein each of the housing and the damper element is curved in complementary directions to define the curved shape of the cavity, and wherein the damper element is curved towards the rotational axis such that the damper element has a concave curved shape.

7. The turbine according to claim 6, characterized in that in, The damping device further comprises a fluid inlet for the damping fluid to enter the cavity, wherein the shape of the cross-section of the damper element is a parabola, and wherein the fluid inlet is defined radially inwardly of a vertex of the cross-section.

8. The turbine according to claim 1, characterized in that in, The damping device further comprises a pressing arm for evenly distributing the damping fluid in the cavity.

9. The turbine according to claim 8, characterized in that Wherein the bearing comprises an inner race and an outer race, and wherein the compression arm is disposed between the damper element and the outer race.

10. The turbine according to claim 1, characterized in that Wherein the bearing comprises an inner race and an outer race, and wherein the outer race is coupled to the damper element.

11. The turbine according to claim 1, characterized in that Wherein the housing circumferentially surrounds the damper element and the bearing.

12. The turbine according to claim 1, characterized in that in, The damping device has a first end and a second end, the second end being axially opposite the first end, and wherein the damping device further includes a first end seal on the first end between the housing and the bearing, and a second end seal on the second end between the housing and the bearing.

13. The turbine according to claim 1, characterized in that The bearing is a ball roller bearing.

14. The turbine according to claim 1, characterized in that The bearing is a tapered roller bearing.

15. The turbine according to claim 1, characterized in that The bearing is a duplex bearing.

16. A damping device for damping vibrations of a shaft rotatable about a rotation axis, the damping device defining a radial direction and an axial direction, the axial direction being parallel to the rotation axis, characterized in that: The damping device comprises: Bearings; case; a damper element, the housing and the damper element being of complementary non-linear shapes to define a cavity therebetween for receiving a damping fluid, the cavity having a length along the axial direction, and the cavity having a semicircular shape and an arcuate portion extending radially inwardly, and a support structure, wherein the housing is located between the support structure and the damper element; Wherein, the length of the cavity is curved away from the rotation axis.

17. The damping device according to claim 16, characterized in that in, The length is curved in a plane extending along the radial direction and the axial direction and including the rotation axis.

18. The damping device according to claim 16, characterized in that: wherein the bearing comprises an inner race and an outer race, wherein the outer race is coupled to the damper element, wherein the damping device has an upstream end and a downstream end, wherein the damping device further comprises a compression arm for evenly distributing the damping fluid within the cavity, a first end seal on the upstream end between the housing and the bearing, and a second end seal on the downstream end between the housing and the bearing, and wherein the compression arm is disposed between the damper element and the outer race.

19. The damping device according to claim 16, characterized in that: The bearing is a roller bearing.

20. A method for damping shaft vibration, characterized in that: The method comprises: rotating the shaft about an axis of rotation; damping the axial vibration of the shaft by a damping device; The overturning moment of the shaft is damped by the damping device, wherein the damping device defines a radial direction and an axial direction, the axial direction being parallel to the rotation axis such that the shaft extends longitudinally along the axial direction, wherein the damping device comprises a bearing operably coupled to the shaft, a housing and a damper element, the housing and the damper element being of complementary non-linear shapes to define a cavity therebetween for receiving a damping fluid, the cavity having a curved shape, and the cavity having a semi-circular shape and an arcuate portion extending radially inwardly, and wherein the damping device further comprises a support structure, wherein the housing is located between the support structure and the damper element; The cavity is curved in a plane extending along the radial direction and the axial direction and including the rotation axis.

Images