DEVICE AND METHOD FOR SEALING A GAS PATH IN A TURBINE
A device for sealing a gas path in a turbine includes a first shroud segment and a slot in a surface of the first shroud segment. A barrier extends inside the slot, and a bypass channel in the slot provides fluid communication between the barrier and the slot to the gas path in the turbine. A method for sealing a gas path in a turbine includes placing a barrier between a first slot in a first shroud segment and a second slot in a second shroud segment and flowing a fluid between the barrier and the first slot to the gas path in the turbine, wherein the fluid flows through a first bypass channel in the first slot.
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The present disclosure generally involves a device and method for sealing a gas path in a turbine.
BACKGROUND OF THE INVENTIONTurbines are widely used in a variety of aviation, industrial, and power generation applications to perform work. Each turbine generally includes alternating stages of peripherally mounted stator vanes and rotating blades. The stator vanes may be attached to a stationary component such as a casing that surrounds the turbine, and the rotating blades may be attached to a rotor located along an axial centerline of the turbine. A compressed working fluid, such as steam, combustion gases, or air, flows along a gas path through the turbine to produce work. The stator vanes accelerate and direct the compressed working fluid onto the subsequent stage of rotating blades to impart motion to the rotating blades, thus turning the rotor and performing work.
Compressed working fluid that leaks around or bypasses the stator vanes or rotating blades reduces the efficiency of the turbine. U.S. Pat. No. 4,902,198 describes an apparatus for film cooling that includes inner and outer shroud segments circumferentially arranged along a gas path. Strip seals seated in slots between adjacent shroud segments reduce the amount of compressed working fluid that escapes from the gas path between adjacent shroud segments. In addition, holes in the shroud segments and intermittent reliefs in the strip seals provide a fluid passage across the strip seals and into the gas path. In this manner, a pressurized fluid may be supplied through the holes, across the reliefs, and into the gas path to prevent leakage from the gas path while also providing film cooling to the strip seals. However, the reliefs in the strip seals weaken the strip seals, possibly leading to premature failure, increased maintenance, and/or foreign material being released into the gas path. As a result, continued improvements in sealing devices and methods for sealing the gas path in a turbine would be useful.
BRIEF DESCRIPTION OF THE INVENTIONAspects 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 device for sealing a gas path in a turbine that includes a first shroud segment and a slot in a surface of the first shroud segment. A barrier extends inside the slot, and a bypass channel in the slot provides fluid communication between the barrier and the slot to the gas path in the turbine.
Another embodiment of the present invention is a device for sealing a gas path in a turbine that includes a first shroud segment that has a first slot and a second shroud segment adjacent to the first shroud segment, wherein the second shroud segment has a second slot. A barrier extends from inside the first slot to inside the second slot, and the barrier has a substantially flat surface facing the gas path and in contact with each of the first and second slots. A first fluid passage to the gas path in the turbine is between the barrier and the first slot.
The present invention may also include a method for sealing a gas path in a turbine. The method includes placing a barrier between a first slot in a first shroud segment and a second slot in a second shroud segment and flowing a fluid between the barrier and the first slot to the gas path in the turbine, wherein the fluid flows through a first bypass channel in the first slot.
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.
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.
Various embodiments of the present invention include a device and method for sealing a gas path in a turbine. In particular embodiments, a barrier between adjacent shroud segments may prevent a compressed working fluid from freely flowing between the shroud segments and out of the gas path. The barrier may extend from inside slots formed in adjacent surfaces of the shroud segments. One or more of the shroud segments may include a fluid port and/or a fluid passage or bypass channel between the barrier and the slot. A pressurized fluid may be supplied through the fluid port to flow between the barrier and the slot and into the gas path to prevent leakage from the gas path while also providing convective and/or film cooling to the slot and barrier. Although exemplary embodiments of the present invention will be described generally in the context of a gas path in a turbine, one of ordinary skill in the art will readily appreciate that embodiments of the present invention may be applied to any gas path containing a pressurized fluid.
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One or more shroud segments 22 may include a fluid port 34 through the shroud segment 22. The fluid port 34 may provide fluid communication through the shroud segment 22 to the slots 26. In this manner, a pressurized fluid such as compressed air, an inert gas, or steam may be supplied through the shroud segment 22 to the slot 26 to flow over the barrier 28 in the slots 26 and between the shroud segments 22 to provide convective and/or film cooling. Alternately or in addition, a fluid passage or bypass channel 36 between the barrier 28 and one or more slots 26 may provide fluid communication to allow the pressurized fluid to flow past the barrier 28 and into the gas path. In
The various embodiments shown in
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 languages of the claims.
Claims
1. A device for sealing a gas path in a turbine, comprising:
- a. a first shroud segment;
- b. a slot in a surface of said first shroud segment;
- c. a barrier extending inside said slot; and
- d. a bypass channel in said slot, wherein said bypass channel provides fluid communication between said barrier and said slot to the gas path in the turbine.
2. The device as in claim 1, further comprising a second shroud segment adjacent to said first shroud segment, wherein said first and second shroud segments have adjacent surfaces.
3. The device as in claim 1, wherein said barrier comprises a plurality of sections that extends between said slot.
4. The device as in claim 1, wherein said bypass channel extends substantially perpendicular to a fluid flow in the gas path in the turbine.
5. The device as in claim 1, wherein said bypass channel comprises a plurality of uniformly spaced grooves in said slot.
6. The device as in claim 1, wherein said bypass channel has an arcuate shape.
7. The device as in claim 1, further comprising a fluid port through said first shroud segment to said slot in said first shroud segment.
8. A device for sealing a gas path in a turbine, comprising:
- a. a first shroud segment, wherein said first shroud segment has a first slot;
- b. a second shroud segment adjacent to said first shroud segment, wherein said second shroud segment has a second slot;
- c. a barrier extending from inside said first slot to inside said second slot, wherein said barrier has a substantially flat surface facing the gas path and in contact with each of said first and second slots; and
- d. a first fluid passage to the gas path in the turbine between said barrier and said first slot.
9. The device as in claim 8, wherein said barrier has a dimension that is larger inside said first and second slots than between said first and second shroud segments.
10. The device as in claim 8, wherein said barrier comprises a plurality of sections that extend from inside said first slot to inside said second slot.
11. The device as in claim 8, wherein said first fluid passage extends in the direction of said second shroud segment.
12. The device as in claim 8, wherein said first fluid passage comprises a plurality of uniformly spaced grooves in said first slot.
13. The device as in claim 8, wherein said first fluid passage comprises a plurality arcuate grooves in said first slot.
14. The device as in claim 8, further comprising a fluid port through said first shroud segment to said first slot in said first shroud segment.
15. The device as in claim 8, further comprising a second fluid passage between said barrier and said second slot to the gas path in the turbine.
16. A method for sealing a gas path in a turbine, comprising:
- a. placing a barrier between a first slot in a first shroud segment and a second slot in a second shroud segment; and
- b. flowing a fluid between said barrier and said first slot to the gas path in the turbine, wherein said fluid flows through a first bypass channel in said first slot.
17. The method as in claim 16, further comprising flowing said fluid through a plurality of grooves in said first slot.
18. The method as in claim 16, further comprising flowing said fluid through a fluid port in said first shroud segment to said first slot in said first shroud segment.
19. The method as in claim 16, further comprising flowing the fluid between said barrier and said second slot to the gas path in the turbine, wherein said fluid flows through a second bypass channel in said second slot.
Type: Application
Filed: Jan 5, 2012
Publication Date: Jul 11, 2013
Applicant: GENERAL ELECTRIC COMPANY (Schenectady, NY)
Inventors: Aaron Gregory Winn (Piedmont, SC), Kevin Thomas McGovern (Simpsonville, SC), Ravichandran Meenakshisundaram (Greenville, SC)
Application Number: 13/343,911
International Classification: F01D 11/08 (20060101);