Combustor and cap assemblies for combustors in a gas turbine
The cap assembly of a turbine combustor includes a plurality of burner tubes sealed against fuel nozzles extending in the tubes. These piston seals are coated with a high velocity oxygen fuel coating to extend their service life. The outer cap body assembly includes concentric seal rings each with cantilevered convex fingers circumferentially offset from one another to seal between the cap assembly casing and the inner liner. The cap assembly casing is provided with a plurality of holes at predetermined locations about the casing to minimize or eliminate response to combustion dynamics.
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The present invention relates to combustors and cap assemblies for combustors having increased service life and particularly relates to combustors and cap assemblies therefor for converting combustors and cap assemblies having a predetermined life cycle to combustors and cap assemblies having extended life cycles.
BACKGROUND OF THE INVENTIONIn gas turbines, a plurality of combustors are typically arranged in an annular array about the axis of the turbine. For example, in one known turbine, eighteen combustors are circumferentially spaced about the turbine axis. Each combustor combines fuel and compressor discharge air into an fuel/air mixture which is then combusted with the resulting gases expanded through the blades of the turbine whereby work is extracted from the turbine.
Combustors including cap assemblies are typically rated for a predetermined number of hours of operation before requiring service. For example, a cap assembly may be rated for 8,000 hours of operation before requiring servicing New versions of the cap assembly, however, are capable of extended hours of operation, e.g. 24,000 hours. This has led to an excess supply of cap assembly hardware having the lower rated hours of operation. These excess cap assemblies thus constitutes stranded assets since the lower rated cap assemblies would not be utilized in upgraded or providing new cap assemblies in new turbines. Accordingly, there has been a need to convert the lower rated cap assemblies which are otherwise stranded assets to the higher rated cap assemblies with extended hours of service whereby the lower rated cap assemblies can be utilized for turbine upgrades or provided in new turbines.
BRIEF DESCRIPTION OF THE INVENTIONIn a preferred embodiment of the present invention there is provided a cap assembly for a turbine combustor comprising: a plurality of burner tubes; a fuel nozzle in each burner tube; and seals between the burner tubes and the fuel nozzles, each seal including a ring having a high velocity oxygen fuel coating on a surface thereof.
In a further preferred embodiment of the present invention there is provided a combustor comprising: a combustor liner; a cap assembly in part received within an end of the liner; a seal between the cap assembly part and said liner including pair of generally annular rings with each said ring having a plurality of spring fingers at circumferentially spaced locations thereabout, said rings being concentrically disposed relative to one another with the spring fingers of one ring circumferentially offset from the spring fingers of another ring enabling the spring fingers of each ring to register with gaps between the spring fingers of said another ring.
In another preferred embodiment of the present invention there is provided a cap assembly for a turbine combustor comprising: a plurality of burner tubes; a fuel nozzle in each burner tube; an outer body sleeve surrounding said plurality of burner tubes and having a plurality of openings sized and located to protect against onset of a mode of combustion dynamics.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the drawings, particularly to
The burner tubes 20 typically have piston seals 28 for sealing about the burner tubes and to the fuel nozzle which is received within the burner tubes. Prior burner tube piston seals constituted a limiting factor in the service life of the cap assembly of the combustor. In accordance with a preferred embodiment of the present invention, to extend the service life of the cap assembly in this aspect of the invention, a high velocity oxygen fuel coating 30 is provided on each piston seal 28 to extend the service life of the piston seal. The material of the seal per se is conventional and may comprise HAST-X and the coating is identified FSX-414. The coating may be applied to a thickness of approximately 7-9 mils whereby superior wear properties are provided to the piston seal 28.
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While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Claims
1. A cap assembly for a turbine combustor comprising:
- a plurality of burner tubes;
- a fuel nozzle in each burner tube; and
- seals between the burner tubes and the fuel nozzles, each seal including a ring having a high velocity oxygen fuel coating on a surface thereof.
2. A cap assembly according to claim 1 wherein said seal is formed of HAST-X.
3. A combustor comprising:
- a combustor liner;
- a cap assembly in part received within an end of the liner; and
- a seal between the cap assembly and said liner including pair of generally annular rings, each said ring having a plurality of spring fingers at circumferentially spaced locations thereabout, said rings being concentrically disposed relative to one another with the spring fingers of one ring circumferentially offset from the spring fingers of another ring enabling the spring fingers of each ring to register with gaps between the spring fingers of said another ring.
4. A combustor according to claim 3 wherein each ring has a margin along an edge thereof with the spring fingers cantilevered from said edge.
5. A combustor according to claim 4 wherein the spring fingers are arcuate with each spring finger following the arcuate contour of registering portions of a pair of spring fingers of said another ring.
6. A combustor according to claim 5 wherein the spring fingers are secured to a casing of the cap assembly, said spring fingers of an outermost ring having radially outward cantilevered convex portions for sealing about an inner surface of the liner.
7. A combustor according to claim 6 wherein said radially outward convex portions have a high velocity oxygen fuel coating.
8. A cap assembly for a turbine combustor comprising:
- a plurality of burner tubes;
- a fuel nozzle in each burner tube;
- an outer body sleeve surrounding said plurality of burner tubes and having a plurality of openings sized and located to protect against onset of a mode of combustion dynamics.
Type: Application
Filed: Apr 13, 2005
Publication Date: Oct 19, 2006
Applicant: General Electric Company (Schenectady, NY)
Inventors: Jere Johnson (Greenville, SC), Mark Bailey (Simpsonville, SC), Robert Berry (Anderson, SC), Stewart Beitz (Greenville, SC), James Monaghan (Moore, SC)
Application Number: 11/104,549
International Classification: F23R 3/42 (20060101);