Patent Application
20250035005
The present application claims priority to Indian Patent Application Serial Number 202311049688 filed on Jul. 24, 2023.
The present disclosure relates generally to turbomachines, and more particularly, to seal assemblies, such as face seal rings, having at least one damping element for reducing radial vibrations of the turbomachine.
Turbomachines include compressors and/or turbines, such as gas turbines, steam turbines, and hydraulic turbines. Generally, turbomachines include a rotor, which may be a shaft or drum, which supports turbomachine blades and a stator. For example, the turbomachine blades may be arranged in stages along the rotor of the turbomachine. The turbomachine may further include various seals to reduce or block flow (e.g., working fluid flow) leakage between various components of the turbomachine. For example, the turbomachine may include one or more face seal rings configured to reduce or block flow leakage between the shaft (e.g., rotating shaft) and a housing of the turbomachine.
However, it can be difficult to design a seal where the center of fluid pressure always passes through the geometrical center of the seal. Therefore, there is usually a pressure moment coupling between radial and axial vibrations of the seal. The presence of radial vibrations of the stator can cause significant reduction in the axial gap between the rotor and the seal, including catastrophic rubs. High seal response amplitude also adds to wear at interfaces, that limits the useful life of the seal.
A full and enabling disclosure, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which refers to the appended Figures, in which:
Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present disclosure.
Reference now will be made in detail to embodiments of the disclosure, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the disclosure, not limitation of the disclosure. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the disclosure. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present disclosure covers such modifications and variations as come within the scope of the appended claims and their equivalents.
The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations. Additionally, unless specifically identified otherwise, all embodiments described herein should be considered exemplary.
The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.
The term “at least one of” in the context of, e.g., “at least one of A, B, and C” refers to only A, only B, only C, or any combination of A, B, and C.
The term “turbomachine” refers to a machine including one or more compressors, a heat generating section (e.g., a combustion section), and one or more turbines that together generate a torque output.
The term “gas turbine engine” refers to an engine having a turbomachine as all or a portion of its power source. Example gas turbine engines include turbofan engines, turboprop engines, turbojet engines, turboshaft engines, etc., as well as hybrid-electric versions of one or more of these engines.
The term “combustion section” refers to any heat addition system for a turbomachine. For example, the term combustion section may refer to a section including one or more of a deflagrative combustion assembly, a rotating detonation combustion assembly, a pulse detonation combustion assembly, or other appropriate heat addition assembly. In certain example embodiments, the combustion section may include an annular combustor, a can combustor, a cannular combustor, a trapped vortex combustor (TVC), or other appropriate combustion system, or combinations thereof.
As used herein, the term “rotor” refers to any component of a rotary machine, such as a turbine engine, that rotates about an axis of rotation. By way of example, a rotor may include a shaft or a spool of a rotary machine, such as a turbine engine.
As used herein, the term “stator” refers to any component of a rotary machine, such as a turbine engine, that has a coaxial configuration and arrangement with a rotor of the rotary machine. A stator may be disposed radially inward or radially outward along a radial axis in relation to at least a portion of a rotor. Additionally, or in the alternative, a stator may be disposed axially adjacent to at least a portion of a rotor.
The terms “low” and “high”, or their respective comparative degrees (e.g., -er, where applicable), when used with a compressor, a turbine, a shaft, or spool components, etc. each refer to relative speeds within an engine unless otherwise specified. For example, a “low turbine” or “low speed turbine” defines a component configured to operate at a rotational speed, such as a maximum allowable rotational speed, lower than a “high turbine” or “high speed turbine” of the engine.
The terms “forward” and “aft” refer to relative positions within a gas turbine engine or vehicle and refer to the normal operational attitude of the gas turbine engine or vehicle. For example, with regard to a gas turbine engine, forward refers to a position closer to an engine inlet and aft refers to a position closer to an engine nozzle or exhaust.
The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows.
As used herein, the terms “axial” and “axially” refer to directions and orientations that extend substantially parallel to a centerline of the gas turbine engine. Moreover, the terms “radial” and “radially” refer to directions and orientations that extend substantially perpendicular to the centerline of the gas turbine engine. In addition, as used herein, the terms “circumferential” and “circumferentially” refer to directions and orientations that extend arcuately about the centerline of the gas turbine engine.
The terms “coupled”, “fixed”, “attached to”, and the like refer to both direct coupling, fixing, or attaching, as well as indirect coupling, fixing, or attaching through one or more intermediate components or features, unless otherwise specified herein.
As used herein, the terms “first”, “second”, “third” and so on may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.
The term “adjacent” as used herein with reference to two walls and/or surfaces refers to the two walls and/or surfaces contacting one another, or the two walls and/or surfaces being separated only by one or more nonstructural layers and the two walls and/or surfaces and the one or more nonstructural layers being in a serial contact relationship (i.e., a first wall/surface contacting the one or more nonstructural layers, and the one or more nonstructural layers contacting the a second wall/surface).
As used herein, the terms “integral”, “unitary”, or “monolithic” as used to describe a structure refers to the structure being formed integrally of a continuous material or group of materials with no seams, connections joints, or the like. The integral, unitary structures described herein may be formed through additive manufacturing to have the described structure, or alternatively through a casting process, etc.
Approximating language, as used herein throughout the specification and claims, is applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about”, “approximately”, and “substantially”, are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value, or the precision of the methods or machines for constructing or manufacturing the components and/or systems. For example, the approximating language may refer to being within a 1, 2, 4, 10, 15, or 20 percent margin. These approximating margins may apply to a single value, either or both endpoints defining numerical ranges, and/or the margin for ranges between endpoints.
Here and throughout the specification and claims, range limitations are combined and interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.
The present disclosure is generally directed to seal assemblies for rotary machines having at least one damping element. The seal assemblies according to embodiments of the present disclosure may be utilized in any rotary machine and, in particular, are suitable for rotary machines including turbomachines and gas turbine engines, and the like. In certain embodiments, the seal assemblies according to the present disclosure include aspirating seals that provide a thin film of pressurized fluid between a face of a seal and a face of a rotor. The thin film of fluid may be provided by one or more aspiration conduits (for example, high-pressure aspiration conduits) that allow fluid, such as pressurized air or gasses within a turbine engine, to flow from a higher-pressure region on one side of the seal assembly to a lower-pressure region on another side of the seal assembly. In other embodiments, the fluid flowing through the aspiration conduits provides a thin film of pressurized fluid between the seal face and the rotor face. The thin film of pressurized fluid may act as a fluid bearing, such as a gas bearing, that inhibits contact between the seal and the rotor. For example, the fluid bearing may be a hydrostatic bearing, an aerostatic bearing, an aerodynamic bearing or a combination of aerostatic and aerodynamic features referred to as a hybrid bearing, or the like.
As such, seal assemblies according to embodiments of the present disclosure are generally considered to be non-contacting seals, in that the fluid bearing generally inhibits contact between the seal face and the rotor face. In particular, the seal assemblies of the present disclosure generally include a primary seal defined by a rotor face of a seal rotor and a slider face of a seal slider. The primary seal may be configured as an aspirating face seal ring, a fluid bearing, a gas bearing, or the like. In addition, or in the alternative, the primary seal may be configured as a radial film riding seal, an axial film riding seal, a radial carbon seal, an axial carbon seal, or the like.
However, for such seals, it can be difficult to design a seal where the center of fluid pressure always passes through the geometrical center of the seal. Therefore, there is usually a pressure moment coupling between radial and axial vibrations of the seal. The presence of radial vibrations of the stator can cause significant reduction in the axial gap between the rotor and the seal, including catastrophic rubs. High seal response amplitude also adds to wear at interfaces, that limits the useful life of the seal. Under high vibration, stalls, and/or high thermal gradients, the non-contacting components can come into contact with each other, thereby causing metal-to-metal rubs and/or seal wear. This contact may change the seal force balance and may also cause the seal to run tighter, which causes more wear.
Accordingly, the present disclosure is generally directed to seal assemblies for rotary machines having at least one damping element. In certain embodiments, for example, the present disclosure is generally directed to seal assemblies that introduce tuned mass damper elements into the design of the face seal ring. In particular, in an embodiment, seal assemblies of the present disclosure include features on the seal slider of the face seal ring to accommodate circumferential mass segments, as well as spring and damper elements. Further, in an embodiment, the spring and damping elements are both in axial and radial directions. Various embodiments of spring elements may be utilized, including but not limited to leaf springs, helical springs, flexures created in-place using wire electrical discharge machining (EDM), etc. As such, in an embodiment, the damping elements allow the seal to remain centered in the radial direction. Isolating the seal from radial vibrations leads to reliable, rub-free operation of the seal in the presence of significant radial vibrations of the stator.
Moreover, in an embodiment, the seal assemblies of the present disclosure operate by addition of as little as about 5% to about 10% additional mass on the seal slider. Additionally, in an embodiment, a damping parameter is defined and selected in a range (e.g., from about 0.1 to about 0.7) that allows two defined parameters: broadband frequency attenuation benefit and operating frequency amplification to be at most 0.5, simultaneously.
Referring now to the drawings,
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As shown particularly in
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In an embodiment, as shown, the seal assembly 100 provides sealing across the annular gap 74. The seal assembly 100 may be used to provide sealing across the annular gap 74 between various types of axially spaced apart forward and aft shafts 52, 54 as illustrated in
Referring now to
Furthermore, the seal assembly 100 includes a secondary seal 80, also referred to herein as a joint, disposed at an interface between the ring carrier 86 and a stator 78 mounted to an engine frame attachment 92. In such embodiments, the secondary seal/joint 80 is capable of linear and tilt displacement to allow the stator 78 to displace with respect to the rotor 14. In particular, as shown, the secondary seal 80 includes a bellow 90 or annular seal that is capable of compressing and expanding to allow the ring carrier 86 to translate axially with respect to the stator 78. In this manner, the ring carrier 86 (and thus the carbon face seal ring 76) may be biased toward the rotor 14 to seal the sealing interface 82.
With the secondary seal 80 in place, leakage between the ring carrier 86 and the stator 78 is limited, meanwhile allowing the ring carrier 86 to move axially away or toward the rotor 14 to accommodate any rotor translation in the axial direction due to different thermal expansion of the various components, or due to thrust reversal. The diameter of the secondary seal 80, or conventionally called pressure-balance diameter, is selected to control a closing force of the ring carrier 86.
In particular embodiments, as the rotor 14 spins with respect to the non-rotating component 88, a circumferential gradient in the film thickness (e.g., the gap between the carbon face seal ring 76 and the rotor 14) is created to generate hydrodynamic pressure at the sealing interface 82. Hence, a separation force prevents the carbon face seal ring 76 from contacting the rotor 14 during motion. This happens when the hydrodynamic opening force is larger than the net closing force created by external pressure acting on the ring carrier 86 and by the bellow 90.
Referring now particularly to
In an embodiment, as shown, the damping element(s) 200 further includes at least one mass element 202. For example, in an embodiment, the mass element(s) 202 of the damping element(s) 200 described herein may increase a total mass of the non-rotating component 88 by about 5% to about 10%. In further embodiments, the total mass of the non-rotating component 88 may be increased by less than 5% or more than 10%. More specifically, as shown in the embodiments of
For example, in an embodiment, as shown particularly in
In further embodiments, the spring element(s) 204 may be any suitable type of spring formed using a variety of techniques. For example, as shown in
Referring now to
Referring now to
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In particular, as shown in
Further aspects are provided by the subject matter of the following clauses:
A seal assembly for a turbomachine, the seal assembly comprising: a rotating component; a non-rotating component comprising a ring carrier, a face seal ring, and a joint disposed between the ring carrier and the non-rotating component, the non-rotating component arranged with the rotating component at a sealing interface, the joint capable of linear and tilt displacement to allow the non-rotating component to displace with respect to the rotating component, the sealing interface defining a gap between the face seal ring and the rotating component; and at least one damping element arranged with the ring carrier for maintaining the seal assembly centrally in a radial direction in the turbomachine, the at least one damping element comprising at least one mass element.
The seal assembly of any preceding clause, wherein the at least one damping element comprises at least one tuned mass damper comprising at least one spring element attached to the at least one mass element.
The seal assembly of any preceding clause, wherein the at least one spring element and the at least one mass element of the at least one damping element are disposed in at least one recess formed in a radially exterior surface of the ring carrier.
The seal assembly of any preceding clause, wherein the at least one spring element extends from a surface of the ring carrier radially inward and into a recess formed between the face seal ring and the ring carrier.
The seal assembly of any preceding clause, wherein the at least one spring element extends from a surface of the ring carrier radially inward between the face seal ring and the ring carrier.
The seal assembly of any preceding clause, wherein the at least one spring element comprises at least one of a helical spring or a leaf spring.
The seal assembly of any preceding clause, wherein the at least one damping element is formed integrally with the ring carrier.
The seal assembly of any preceding clause, wherein the at least one damping element comprises a plurality of damping elements, the plurality of damping elements extending in both axial and radial directions.
The seal assembly of any preceding clause, wherein the at least one damping element further comprises a flexible hairpin carrier, the at least one mass element being a radial foil damper supported by the spring element and arranged within the flexible hairpin carrier.
The seal assembly of any preceding clause, wherein the at least one damping element further comprises a flexible hairpin carrier, the at least one mass element being a fluid restricted by a plurality of seal members arranged within the flexible hairpin carrier.
The seal assembly of any preceding clause, wherein the at least one mass element of the at least one damping element further comprises one or more mass balls moveably arranged in one or more channels containing a viscous fluid.
The seal assembly of any preceding clause, wherein the at least one mass element of the at least one damping element increases a total mass of the non-rotating component by about 5% to about 10%.
The seal assembly of any preceding clause, wherein a mass fraction of the at least one mass element of the at least one damping element ranges from about 0.05 to about 0.25 and a damping parameter represented as ca/(2√(maka) ranges from about 0.1 to about 0.7 to provide an optimal combination of a broadband amplification and an operating frequency amplification less than 0.5.
The seal assembly of any preceding clause, wherein the seal assembly is configured as at least one of a carbon face seal ring, an aspirating face seal ring, a hybrid face seal ring, a fluid bearing, a gas bearing, or a film riding seal.
A turbomachine, comprising: a rotor; a stator arranged with the rotor at a sealing interface; and a seal assembly at the sealing interface, the seal assembly comprising: a ring carrier; a face seal ring; and a joint disposed between the ring carrier and the non-rotating component, the joint capable of linear and tilt displacement to allow the stator to displace with respect to the rotor, the sealing interface defining a gap between the face seal ring and the rotor; and at least one damping element arranged with the ring carrier for maintaining the seal assembly centrally in a radial direction in the turbomachine, the at least one damping element comprising at least one mass element.
The turbomachine of any preceding clause, wherein the at least one damping element comprises at least one tuned mass damper comprising at least one spring element attached to the at least one mass element.
The turbomachine of any preceding clause, wherein the at least one spring element and the at least one mass element of the at least one damping element are disposed in at least one recess formed in a radially exterior surface of the ring carrier.
The turbomachine of any preceding clause, wherein the at least one spring element extends from a surface of the ring carrier radially inward and into a recess formed between the face seal ring and the ring carrier.
The turbomachine of any preceding clause, wherein the at least one spring element extends from a surface of the ring carrier radially inward between the face seal ring and the ring carrier.
The turbomachine of any preceding clause, wherein the at least one spring element comprises at least one of a helical spring or a leaf spring.
This written description uses exemplary embodiments to describe the presently disclosed subject matter, including the best mode, and also to enable any person skilled in the art to practice such subject matter, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the presently disclosed subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such 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 with insubstantial differences from the literal languages of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202311049688 | Jul 2023 | IN | national |
