The present invention generally involves a turbomachine. More specifically, the invention relates to locking spacer assemblies for securing rotor blades to a rotor disk of the turbomachine.
Various turbomachines such as a gas turbine or steam turbine include a shaft, multiple rotor disks coupled to the shaft and various rotor blades mounted to the rotor disks. A conventional gas turbine includes a rotatable shaft with various rotor blades mounted to discs in the compressor and turbine sections thereof. Each rotor blade includes an airfoil over which pressurized air, combustion gases or other fluids such as steam flows, and a platform at the base of the airfoil that defines a radially inner boundary for the air or fluid flow.
The rotor blades are typically removable, and therefore include a suitable root portion such as a T-type root portion that is configured to engage a complementary attachment slot in the perimeter of the rotor disk. The root may either be an axial-entry root or a circumferential-entry root that engages with corresponding axial or circumferential slots formed in the disk perimeter. A typical root includes a neck of minimum cross sectional area and root protrusions that extend from the root into a pair of lateral recesses located within the attachment slot.
For circumferential roots, a single attachment slot is formed between forward and aft continuous circumferential posts or hoops that extend circumferentially around the entire perimeter of forward and aft faces of the rotor disk. The cross-sectional shape of the circumferential attachment slot includes lateral recesses defined by the forward and aft rotor disk posts or hoops that cooperate with the root protrusions of the rotor blades to radially retain the individual blades during turbine operation.
In the compressor section of a gas turbine, for example, rotor or compressor blades (specifically the root components) are inserted into and around the circumferential slot and rotated approximately ninety degrees to bring the root protrusions of the rotor blades into contact with the lateral recesses to define a complete stage of rotor blades around the circumference of the rotor disks. The rotor blades include platforms at the airfoil base that may be in abutting engagement around the slot. In other embodiments, spacers may be installed in the circumferential slot between adjacent rotor blade platforms. Once all of the blades (and spacers) have been installed, a final remaining space or spaces in the attachment slot is typically filled with a specifically designed spacer assembly, as generally known in the art.
A common technique used to facilitate the insertion of the final spacer assembly into the circumferential slot is to include a non-axi symmetric loading slot in the rotor disc. Various conventional spacer assemblies have been designed to eliminate the need for a loading slot in the rotor disk. However, these assemblies include complex devices. These conventional assemblies are generally difficult to assemble, costly to manufacture and may result in rotor imbalance. Accordingly, there is a need for an improved locking spacer assembly that is relatively easy to assemble within the final space between platforms of adjacent rotor blades of a turbomachine such as compressor and/or turbine rotor blades of a gas turbine.
Aspects and advantages of the invention are set forth below in the following description, or may be obvious from the description, or may be learned through practice of the invention.
One embodiment of the present invention is a locking spacer assembly for insertion into a circumferential attachment slot between platforms of adjacent rotor blades. The locking spacer assembly includes a first end piece configured to fit into a space between the platforms of adjacent rotor blades. The first end piece comprises an outer surface and an inner surface. The outer surface has a profile that is adapted to project into the attachment slot. A second end piece is configured to fit into a space between the platforms. The second end piece comprises an outer surface and an inner surface. The outer surface has a profile that is adapted to project into the attachment slot. The inner surfaces of the first and second end pieces generally face each other. A spacer block is configured to be inserted between the inner surfaces of the first and second end pieces. The spacer block is bonded to each of the first end piece and the second end piece.
Another embodiment of the present invention is a locking spacer assembly for insertion into a circumferential attachment slot between platforms of adjacent rotor blades. The locking spacer assembly includes a first end piece configured to fit into a space between the platforms of adjacent rotor blades. The first end piece comprises an outer surface and an inner surface. The outer surface has a profile that is adapted to project into the attachment slot. A second end piece is configured to fit into a space between the platforms. The second end piece comprises an outer surface and an inner surface. The outer surface has a profile that is adapted to project into the attachment slot. The inner surfaces of the first and second end pieces generally face each other. The first end piece is bonded to the second end piece along a joint defined between the inner surfaces.
Another embodiment of the present invention is a turbomachine. The turbomachine includes a compressor, a combustor and a turbine. At least one of the compressor or the turbine comprises a rotor disk having forward and aft posts. The forward and aft posts at least partially define a continuous circumferentially extending attachment slot. The turbomachine further includes a plurality of rotor blades. Each of the rotor blades extends from a corresponding one platform of a plurality of platforms. Each of the plurality of platforms is secured to the attachment slot by an inwardly extending root. A locking spacer assembly is disposed in a space between at least two of the plurality of platforms. The locking spacer assembly comprises a first end piece that is configured to fit into a space between the platforms of the adjacent rotor blades. The first end piece comprises an outer surface and an inner surface. The outer surface has a profile that is adapted to project into the attachment slot. A second end piece is configured to fit into the space between the platforms. The second end piece comprises an outer surface and an inner surface. The outer surface has a profile adapted to project into the attachment slot. The inner surfaces of the first and second end pieces generally face each other. The first end piece is bonded to the second end piece.
Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the specification.
A full and enabling disclosure of the present invention, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:
Reference will now be made in detail to present embodiments of the invention, one or more examples of which are illustrated 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 description have been used to refer to like or similar parts of the invention. As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.
As used herein, 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. The term “radially” refers to the relative direction in a plane that is substantially perpendicular to an axial centerline of a particular component, and the term “axially” refers to the relative direction in a plane that is substantially parallel to an axial centerline of a particular component.
Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
Although exemplary embodiments of the present invention will be described generally in the context of a gas turbine for purposes of illustration, one of ordinary skill in the art will readily appreciate that embodiments of the present invention may be applied to any turbomachine having a shaft and rotating blades coupled to the shaft such as a steam turbine or the like, and are not limited to a gas turbine unless specifically recited in the claims.
Referring now to the drawings, wherein identical numerals indicate the same elements throughout the figures,
Multiple rotor wheels or disks 28 are disposed coaxially along the shaft 24 within the compressor 14 and/or the turbine 22. Each rotor disk 28 is configured to receive a plurality of radially extending rotor blades 30 that are circumferentially spaced around and removably fixed to the rotor disk 28. The rotor blades 30 may be configured for use within the compressor 14 such as a compressor rotor blade 32 or for use within the turbine 22 such as a turbine bucket or turbine rotor blade 34. Each blade 30 has a longitudinal centerline axis 36 and includes an airfoil portion 38 having a leading edge 40 and a trailing edge 42.
In operation, a working fluid 44 such as air is routed into the compressor 14 where it is progressively compressed in part by the compressor rotor blades 32 as it is routed towards the combustion section 16. A compressed working fluid 46 flows from the compressor 14 and is supplied to the combustion section 16. The compressed working fluid 46 is distributed to each of the combustors 18 where it is mixed with a fuel to provide a combustible mixture. The combustible mixture is burned to produce combustion gases 48 at a relatively high temperature and high velocity. The combustion gases 48 are routed through the turbine 22 where thermal and kinetic energy is transferred to the turbine rotor blades 34, thereby causing the shaft 24 to rotate. In particular applications, the shaft 24 is coupled to a generator (not shown) to produce electricity.
The root portion 52 may include protrusions 58 that are received into lateral recesses 60 defined within the attachment slot 54 and at least partially defined by recessed wall portions 62 of the post components 56. The forward and aft post components 56 and/or the rotor disk 28 may further define sidewall portions 64 of the attachment slot 54. It should be readily appreciated that the configuration of the root portion 52 and attachment slot 54 provided in
It should be appreciated that in particular embodiments, the locking spacer assembly 100 can be used to fill final spaces 68 between platforms 50 of adjacent rotor blades 30 including the compressor rotor blades 32 located within the compressor 14 and/or the turbine rotor blades 34 located within the turbine 22. As such, the locking spacer assembly 100 will be generally described below as being installed between platforms 50 of adjacent rotor blades 30, wherein the platforms 50 may be part of a compressor rotor blade 32 or a turbine rotor blade 34 so as to fully encompass both applications.
As shown in
The outer surface 122 has a profile that is defined along the root portion 112. The profile is adapted to project into a first lateral recess 126 of the attachment slot 54. For example, the profile may include a first projection 128. The first projection 128 may be shaped to project into the first lateral recess 126. The outer surface 122 may be curved or otherwise shaped so as to mirror the curve of the post components 56. It should be readily appreciated that the first projection 128 can have any desired profile and need not have the particular profile illustrated in
In particular embodiments, an arcuate groove 130 or other stress relief feature such as a blend or fillet is defined by the first end piece 102 proximate to a location where the first projection 128 is defined or extends generally axially outwardly from the root portion 112 of the first end piece 102. The arcuate groove 130 may be included to provide a point of low stress or a location for stress relief on the first end piece 102. As later illustrated, the arcuate groove 130 may be located on the root portion 112 at a corner formed between the forward or aft post component 56 and the first lateral recess 126.
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The outer surface 148 has a profile that is defined along the root portion 138. The profile of the outer surface 148 is adapted to project into a second lateral recess 152 of the attachment slot 54. For example, the profile may include a second projection 154. The second projection 154 may be shaped to project into the second lateral recess 152. The outer surface 148 may be curved or otherwise shaped so as to mirror the curve of the post components 56. It should be readily appreciated that the second projection 154 can have any desired profile and need not have the particular profile illustrated in
In particular embodiments, an arcuate groove 156 or other stress relief feature such as a blend or fillet is defined by the second end piece 104 proximate to a location where the second projection 154 is defined or extends generally axially outwardly from the root portion 138 of the second end piece 104. The arcuate groove 156 may be included to provide a point of low stress or a location for stress relief on the second end piece 104. As later illustrated, the arcuate groove 156 may be located on the root portion 138 at a corner formed between the forward or aft post component 56 and the second lateral recess 152.
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In particular embodiments, as shown in
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In this configuration, one of the first or second end pieces 102, 104 are inserted into the attachment slot 54 and the other of the first or second end pieces 102, 104 is angled into the attachment slot 54 such that the first and second inner surfaces 120, 146 are adjacent. The first and second end pieces 102, 104 are then bonded together along the connection joint 170, thereby locking the locking spacer assembly 100 into position and securing the adjacent rotor blades 30 to the rotor disk 28.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated 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. 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 language of the claims.