BLADE DISK SEAL
An apparatus and method are disclosed for reducing the operating stresses in a disk of a gas turbine engine while providing a seal plate to minimize leakage of a cooling fluid from the blades positioned in the disk. The seal plate is fastened to a tang of one or more of the blades. The seal plate configuration can be utilized with a newly manufactured disk and blades or with a modification to an existing disk and blades. The disk, blade, and seal plate configuration reduce operating stresses in the disk that are caused by mechanical loading on the disk by one or more rotating blades.
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This application claims priority to the Provisional Patent Application having Ser. No. 61/012,475 and filed on Dec. 10, 2007.
TECHNICAL FIELDThe present invention relates to gas turbine engines. More particularly, embodiments of the present invention relate to an apparatus and method for reducing stress in a blade disk while minimizing leakage of cooling fluids directed towards one or more blades.
BACKGROUND OF THE INVENTIONGas turbine engines operate to produce mechanical work or thrust. Specifically, land-based gas turbine engines typically have a generator coupled thereto for the purposes of generating electricity. A gas turbine engine comprises a number of components including a compressor section which has a series of rotating compressor blades. The compressor, which receives air from an engine inlet, passes the air through the compressor, where the pressure of the air increases. The compressed air is then directed into one or more combustors where fuel is mixed with the compressed air and the mixture is ignited. The hot combustion gases are then directed into a turbine section, which is coupled by a shaft to the compressor section. The hot combustion gases pass through the turbine causing the turbine blades, which are attached to disks, to rotate, which also drives the compressor. Depending on the type of gas turbine engine, an electrical generator may also be coupled to the engine shaft for harnessing its mechanical output in order to generate electricity.
Referring to
Embodiments of the present invention are directed towards a system and method for, among other things, reducing stress levels in a disk assembly while providing a seal between a portion of the disk and one or more blades for a gas turbine engine.
The present invention provides embodiments for a disk assembly of a gas turbine engine in which a seal plate is secured thereto in order to prevent leakage of cooling air that is directed to cool a blade installed in the disk. The assembly has a disk with generally axially extending slots for receiving one or more blades. In one embodiment, each blade in the disk has a tang that extends radially inward, and one or more seal plates positioned to receive and engage the tang. The tang of the blade is secured to a seal plate by a fastener.
In an alternate embodiment of the present invention, a method of providing a sealing configuration between tangs of one or more blades and a disk is provided. This embodiment can be utilized in a variety of disk configurations, including modifying an existing turbine disk to remove areas of high concentrated stress. The method includes making alterations to the tang of the blade in order for it to mate with a seal plate. These alterations include machining a flat surface into a bottom of the tang and drilling a through hole in the tang. Once the blade is placed in the slot of the disk, the seal plate is placed around a portion of the tang such that a fastener can be placed through the seal plate and the tang, thereby joining the seal plate and tang together.
In yet another embodiment, a seal plate capable of minimizing cooling fluid leakage between a disk and one or more blades is provided. In one embodiment, the seal plate has generally parallel first and second members that are connected by a leg with the first and second members each having through holes for receiving a fastener. The first and second members are spaced apart a distance sufficient to receive a blade tang therebetween.
Additional advantages and features of the present invention will be set forth in part in a description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned from practice of the invention.
The present invention is described in detail below with reference to the attached drawing figures, wherein:
The subject matter of the present invention is described with specificity herein to meet statutory requirements. However, the description itself is not intended to limit the scope of this patent. Rather, the inventors have contemplated that the claimed subject matter might also be embodied in other ways, to include different components, combinations of components, steps, or combinations of steps similar to the ones described in this document, in conjunction with other present or future technologies.
Referring initially to
One or more blades 310 are positioned within the blade slots 306 and extend radially outward from the disk 300. Referring now to
Referring to
Turning to
Referring to
The disk 300 utilizes one or more fasteners 340 to secure the seal plate 326 to the tang 316 of the blade 310. Fasteners 340 are placed through the one or more holes 336 in the first member 328, through the hole 324 in the tang 316, and engages a set of threads 342 of the one or more threaded holes 338 in the second member 332. This arrangement is depicted in
As previously discussed, a sealing arrangement is required for blades which receive a supply of cooling fluid. While embodiments of this invention can be applied to a variety of blades and disk designs, including newly manufactured components, one particular embodiment in which this invention is applicable is with respect to a method of modifying an existing turbine disk having regions of excessive stress in an attachment area between a blade and the disk. For clarity purposes, the same figures will be used in describing this embodiment of the present invention that is directed towards modifying a turbine disk, as have been previously referenced.
As previously discussed, the turbine disk 300 has a plurality of blade slots 306 for receiving blades along its outer circumferential surface 302. However, this disk also contains a tangential cooling cavity 350 (see
An alternate embodiment of the present invention applies the seal plate arrangement previously discussed to a modified blade disk, when the structure of the cooling cavity 350 adjacent to known high stress regions has been modified. Referring back to
Once modifications have been made to the disk 300 and blade 310, the blade 310 is then placed into the blade slot 306 of the now modified disk 300 and a seal plate 326 is slid at least partially around the tang 316 and into a seal slot 322 of the disk 300. Referring to
Once the seal plate 326 is positioned around the tang 316, a threaded fastener 340 is placed through the through hole 336 in the seal plate 326 and through the through hole 324 in the tang 316 such that the fastener 340 engages the threaded hole 338 in the second member 332 of the seal plate 326. The fastener 340 is then secured to the first member 328 by a means such as tack welding so as to prevent the fastener 340 from backing out and coming loose during engine operation.
Although this seal plate 326 has been described in use with a particular modification to a blade disk 300, as shown in
Depending on the blade construction, the seal plate geometry can vary to include additional members similar to members 328 and 332. Also, the spacing between the members 328 and 332 can vary and as a result, the length of the leg 333 will also vary. Furthermore, depending on the blade and disk configuration, it is possible that more than one seal plate 326 will be required. For example, multiple seal plates 326 can be used, with one at a forward end of a blade/disk assembly and another at an aft end of the blade/disk assembly.
While the seal plate 326 and fastener 340 have been described with respect to a threaded engagement, this is but one type of coupling. Alternate forms of fastening the seal plate 326 and the blade tang 316 together are envisioned as such, slight modifications to the seal plate 326 and/or blade tang 316 may be required. For example, depending on the fastener type, the hole 338 may not be threaded, but instead may be a through hole or a tapered hole so as to engage an alternate form of the fastener 340.
Although the present invention has been described in terms of a threaded fastener, the fastener 340 is not limited to this configuration. In fact, alternate sealing arrangements between the seal plate 326 and the blade tang 316 can be utilized, such as a snap fit or trapping the seal plate 326 between the tang 316 and the disk 310. Furthermore, the second member 332 may not have a hole 338. In this embodiment, a fastener can pass through the first member and the tang and contact the second member 332
An alternate embodiment of the present invention is shown in
The circumferentially-extending member 1106 also includes an angled surface 1114 that mates to an angled surface 1116 of the blade tang 1118. During operation, as the blade 1104 rotates, the blade 1104 moves slightly radially outward away, from the disk 1102 due to the circumferential pull created by the blade weight and rotation. However, the blade 1102 is fixed in place radially by an attachment (not shown). The coverplate 1100, is secured to a blade tang 1118 by one or more pins 1120 that pass through respective openings in the coverplate 1100 and tang 1118. This securing means permits the coverplate 1100 to move slightly radially outward such that the angled surface 1114 of the coverplate comes into and maintains a line-on-line contact with the blade tang 1118.
Referring now to
In this alternate embodiment, the second vertical member 1110 further comprises a slot 1122 that contains a generally circumferentially-extending seal 1124 that has a circular cross section, such as a wire seal. The slot 1122 is formed from material removed or void from the radially outer portion of the second vertical member 1110. The circumferentially-extending seal 1124 extends the circumference of the disk 1102 to provide a supplemental seal to the angled surfaces 1114 and 1116.
The present invention has been described in relation to particular embodiments, which are intended in all respects to be illustrative rather than restrictive. Alternative embodiments will become apparent to those of ordinary skill in the art to which the present invention pertains without departing from its scope.
From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects set forth above, together with other advantages which are obvious and inherent to the system and method. It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and within the scope of the claims.
Claims
1. A disk assembly for a gas turbine engine comprising:
- a disk having an outer circumferentially extending surface, a center axis, a thickness, and a plurality of blade slots having a slot length extending at least partially through the thickness, the plurality of blade slots are spaced generally equally about the outer circumferentially extending surface;
- one or more blades positioned in each of the blade slots and extending radially outward from the disk, the one or more blades each having a root portion, an airfoil portion, and a tang;
- one or more seal plates configured to receive the tang of the blade so as to secure the one or more seal plates to the tangs of the one or more blades;
- wherein at least one seal is formed between the tang of the blade and the one or more seal plates.
2. The disk assembly of claim 1, wherein the root portion has a root length and a profile corresponding substantially to the blade slots.
3. The disk assembly of claim 1, further comprising one or more fasteners for securing the one or more seal plates to the tangs of the one or more blades.
4. The disk assembly of claim 3, wherein the tang has a thickness and extends radially inward and is spaced axially from the root portion by a seal slot, the tang also having a through hole.
5. The disk assembly of claim 4, wherein the seal plate comprises a first member having a first thickness and a second member having a second thickness, the first member being generally parallel to the second member and separated from the second member by a leg, the first member having one or more through holes in the first thickness and the second member having one or more holes in the second thickness.
6. The disk assembly of claim 5, wherein the leg of the seal plate contacts the tang upon rotation of the disk assembly.
7. The disk assembly of claim 5, wherein the one or more fasteners and the one or more holes in the second member are threaded such that when one or more fasteners are placed through the one or more holes in the first member, through the hole in the tang, the one or more fasteners engage with a corresponding one or more threaded holes in the second member.
8. The disk assembly of claim 7, wherein the one or more fasteners are positioned such that at least the second member of the one or more seal plates contacts the tang.
9. A seal plate for minimizing a cooling fluid leakage between a portion of a disk and one or more blades, the seal plate comprising:
- a first member having a first thickness, a first height, a first width and a first through hole;
- a second member having a second thickness, a second height, and a second width, where the second member is generally parallel to the first member; and
- a leg connecting the first member to the second member, the leg having at least one flat portion; wherein
- the seal plate is capable of being positioned to seal a joint between a portion of the disk and the one or more blades and is secured to the one or more blades by a fastener.
10. The seal plate of claim 9, wherein the first thickness is less than the second thickness and the first height is greater than the second height.
11. The seal plate of claim 9, wherein the second member further comprises a second through hole.
12. The seal plate of claim 9, wherein the first through hole has a constant diameter and the second through hole is threaded.
13. The seal plate of claim 12, wherein the fastener has threads that correspond to the threads of the second through hole.
14. The seal plate of claim 9, wherein the first and second widths are equal to or greater than a width of a slot in the disk.
15. A disk assembly for a gas turbine engine comprising:
- a disk having an outer circumferentially extending surface, a center axis, a thickness, a hook portion, and a plurality of blade slots having a slot length extending at least partially through the thickness, the plurality of blade slots are spaced generally equally about the outer circumferentially extending surface;
- one or more blades positioned in each of the blade slots and extending radially outward from the disk, the one or more blades each having a root portion, an airfoil portion, and a tang;
- one or more seal plates configured to engage the hook portion of the disk so as to secure the one or more seal plates to the tangs of the one or more blades;
- wherein at least one seal is formed between the hook portion of the disk and the one or more seal plates.
16. The disk assembly of claim 15 further comprising a pin for securing the seal plate to the tang of the blade.
17. The disk assembly of claim 16, wherein the pin prevents circumferential movement of the seal plate relative to the blade.
18. The disk assembly of claim 15, wherein the seal is formed upon rotation of the disk assembly by centrifugal loads such that the one or more seal plates move radially outward and contact a portion of the hook portion of the disk.
19. The disk assembly of claim 18, wherein the seal is formed along corresponding chamfered surfaces of the hook portion and seal plates.
20. The disk assembly of claim 15, wherein the one or more plates comprises up to six plates.
21. A seal plate for minimizing a cooling fluid leakage between a portion of a disk and one or more blades, the seal plate comprising:
- a circumferentially extending base member;
- a first vertical member extending radially outward from an end of the circumferentially extending base member; and,
- a second vertical member extending radially outward from the first vertical member; wherein
- the first and second vertical members are connected by an axial member.
22. The seal plate of claim 21, wherein the circumferentially-extending base member has a portion with an angled surface.
23. The seal plate of claim 22, wherein the angled surface contacts the angled surface of a blade tang to form a sealing surface.
24. The seal plate of claim 21 further comprising one or more openings for a pin.
25. The seal plate of claim 24, wherein the pin attaches to the tang of the blade.
26. The seal plate of claim 21 further comprising a circumferentially-extending seal positioned between the second vertical member and the disk.
Type: Application
Filed: Dec 9, 2008
Publication Date: Jun 11, 2009
Applicant: ALSTOM TECHNOLOGIES, LTD. LLC (BADEN)
Inventors: J. Page Strohl (Stuart, FL), Anthony Petett (Lexington Park, MD), Robert J. Kraft (Tequesta, FL)
Application Number: 12/330,755
International Classification: F01D 5/30 (20060101);