Fuel nozzle centering device and method for gas turbine combustors

Information

  • Patent Grant
  • 6250062
  • Patent Number
    6,250,062
  • Date Filed
    Tuesday, August 17, 1999
    25 years ago
  • Date Issued
    Tuesday, June 26, 2001
    23 years ago
Abstract
A fuel nozzle centering assembly and method employ bodies of a substantially wearable and sacrificial material mounted to an outer periphery of a tip of a burner fuel nozzle for a gas turbine combustor. The tip of the fuel nozzle extends through an opening of an annular collar attached to a liner of a main combustion chamber of the gas turbine combustor and an outer periphery of the tip is disposed radially inwardly from the annular collar such that the bodies of sacrificial material are disposed between the outer periphery of the fuel nozzle tip and the annular collar of the liner and space the fuel nozzle tip from the liner collar. The bodies of material prevent the fuel nozzle tip from contacting the liner collar during assembling of the fuel nozzle into the liner. The bodies wear away substantially upon initial operation of the combustor such that the bodies will reduce contact with the liner collar during further operation of the combustor and the fuel nozzle tip will remain spaced from and out of contact with the liner collar during operation of the combustor.
Description




BACKGROUND OF THE INVENTION




The present invention generally relates to gas turbine combustors and, more particularly, is concerned with a fuel nozzle centering device and method for gas turbine combustors.




As depicted in

FIGS. 1

to


3


, a prior art gas turbine generally includes a combustor


10


having a main combustion chamber


12


and one or more burners


14


attached to the main combustion chamber


12


. Compressed air enters the burner


14


from the left and flows to the right through the combustor


10


. Air is provided by a compressor (not shown) and may be reversed flowed over the combustor


10


before entering the burner


14


. While only one burner


14


is shown for clarity of illustration, a plurality of burners


14


is preferably used. Typically, five or six burners are arranged in a circular array on the main combustion chamber


12


.




The main combustion chamber


12


includes a liner


16


having an upstream end


16


A and an opening


18


defined in the liner


16


by an annular collar


20


attached to the upstream end


16


A of the liner


16


. The burner


14


typically includes a cylindrical flow tube (not shown) and a fuel nozzle


22


concentrically disposed within the flow tube. The fuel nozzle


22


includes a cylindrical hub


24


, an annular flange


26


interconnected with and extending circumferentially around the hub


24


, and a tip


28


interconnected with and disposed downstream from the hub


24


. The fuel nozzle flange


26


defines a plurality of through-holes


30


which are circumferentially spaced apart from one another. The combustor


10


also includes a cover


32


and a plurality of bolts


34


. The cover


32


has a plurality of holes


36


defined therein being alignable with the holes


30


of the fuel nozzle flange


26


. The bolts


34


are inserted through the through-holes


30


of the fuel nozzle flange


26


and into the holes


36


of the cover


34


and thereby removably secure the fuel nozzle flange


26


and combustor cover


32


to one another. The fuel nozzle tip


28


has an outer periphery


38


where it is assembled into the liner collar


20


.




Due to many stack-up tolerances involved in assembling fuel nozzles of burners into the liner of the main combustion chamber, fuel nozzle misalignment is commonplace and causes a redundancy in liner head end support by sharing the support load between the fuel nozzle and liner stops (not shown). Operational experience and analysis has shown that this type of system creates an environment where dynamics are higher and part wear is increased. In the current system, fuel nozzles are assembled into liner collars through a complex assembly of parts. To allow for the stack-up of tolerances, clearances between the parts, especially at the bolts, is necessary. Because of this, misalignment of the fuel nozzle often occurs.




Various devices and methods have been developed over the years toward providing a solution of the aforementioned problem of misalignment of the fuel nozzle. The primary devices and methods employed in the industry have been the use of floating liner collars


40


, as shown in

FIG. 2

, and of a body bound arrangement, as shown in FIG.


3


. The floating liner collar


40


makes up for fuel nozzle misalignment by allowing the liner collar to “float” through a predetermined clearance. While this device and method has been somewhat satisfactory, it is expensive due to its complexity and has been prone to create additional wear problems, particularly in the liner collar itself. The body bound arrangement usually replaces three of the bolt through-holes with tapered bolts


42


that attempt to center the fuel nozzle. After time, however, the bolts or holes become worn and the same misalignment problems arise. Further, due to its complexity, this design can be difficult and expensive for retrofit applications.




Consequently, a need still exists for an innovation which will provide a solution to the aforementioned problems in the prior art without introducing any new problems in place thereof.




SUMMARY OF THE INVENTION




The present invention provides a fuel nozzle centering device and method for gas turbine combustors designed to satisfy the aforementioned need. The fuel nozzle centering device and method alleviate fuel nozzle contact such that system dynamics are reduced, part wear is reduced and overall combustor life is extended.




In an exemplary embodiment of the present invention, a gas turbine combustor comprises a main combustor chamber having a liner and an annular collar mounted to the liner so as to define an opening therethrough, at least one burner attached to the main combustor chamber and having a fuel nozzle mounted adjacent to the liner with a tip of the fuel nozzle disposed through the opening of the annular collar of the main combustor chamber and an outer periphery of the tip disposed within and adjacent to the annular collar, and a fuel nozzle centering device mounted to the tip of the fuel nozzle and disposed between the outer periphery of the fuel nozzle tip and the annular collar of the liner, the device including a sacrificial body of material contacting the liner collar and spacing the fuel nozzle tip radially inwardly from the liner collar such that the fuel nozzle tip is prevented from contacting the liner collar during assembling of the fuel nozzle of the burner to the liner of the main combustion chamber, the sacrificial body of material being at least partially wearable away upon initial operation of the gas turbine combustor such that the sacrificial body of material will diminish in quantity and thereby reduce contact with the liner collar during further operation of the gas turbine combustor so that the fuel nozzle tip will remain spaced from and substantially out of contact with the liner collar of the main combustion chamber during continued operation of the gas turbine combustor. The body of sacrificial material can have a substantially annular configuration and extend around the outer periphery of the fuel nozzle tip of the burner. The body of material may be in the form of a bead, tape or a wire. The device can include a plurality of bodies of the material having substantially the same sizes and being are spaced apart such as at equal distances from one another.




In another exemplary embodiment of the present invention, a method for centering a fuel nozzle of a burner in a gas turbine combustor comprises the steps of providing at least one and, preferably, a plurality of bodies of a substantially wearable and sacrificial material, mounting the bodies to an outer periphery of a tip of a fuel nozzle of a burner for a gas turbine combustor, assembling the fuel nozzle with its tip extending through an opening of an annular collar attached to a liner of a main combustion chamber of the combustor, and preventing the fuel nozzle tip of the burner from coming into contact with the liner collar of the main combustion chamber during the assembling step by the bodies contacting the liner collar of the main combustion chamber and spacing the fuel nozzle tip of the burner from the liner collar. The method further comprises the step of wearing away the bodies at least partially and, preferably, substantially upon initial operation of the gas turbine combustor such that the bodies will reduce contact with the liner collar of the main combustion chamber during further operation of the combustor and the fuel nozzle tip of the burner will remain spaced from and out of contact with the liner collar of the main combustion chamber during operation of the combustor.




These and other features and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there is shown and described an illustrative embodiment of the invention.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a schematic fragmentary longitudinal sectional view of a prior art gas turbine combustor showing one prior art arrangement wherein a tip of a fuel nozzle of a burner is assembled into a collar of a liner of a main combustion chamber of the prior art combustor.





FIG. 2

is a schematic fragmentary longitudinal sectional view of the prior art gas turbine combustor generally similar to that of

FIG. 1

but showing another prior art arrangement wherein a floating collar is disposed between the fuel nozzle tip of the burner and the main combustion chamber liner of the prior art combustor.





FIG. 3

is a schematic fragmentary longitudinal sectional view of the prior art gas turbine combustor generally similar to that of

FIG. 1

but showing still another prior art arrangement wherein bolt through holes of the prior art combustor shown in

FIG. 1

are replaced with tapered bolts.





FIG. 4

is a schematic fragmentary longitudinal sectional view of the prior art gas turbine combustor generally similar to that of

FIG. 1

but showing a first exemplary embodiment of a fuel nozzle centering device of the present invention disposed between the fuel nozzle tip of the burner and the liner collar of the main combustion chamber of the prior art combustor.





FIG. 5

is an enlarged schematic cross-sectional view of the fuel nozzle centering device taken along line


5





5


of FIG.


4


.





FIG. 6

is a schematic cross-sectional view similar to that of

FIG. 5

but showing a second exemplary embodiment of the fuel nozzle centering device of the present invention.





FIG. 7

is a schematic cross-sectional view similar to that of

FIG. 6

but showing a third exemplary embodiment of the fuel nozzle centering device of the present invention.











DETAILED DESCRIPTION OF THE INVENTION




Referring to the drawings and particularly to

FIGS. 4 and 5

, there is illustrated a fuel nozzle centering device, generally designated


50


, of the present invention used in the prior art gas turbine combustor


10


of FIG.


1


. The fuel nozzle centering assembly


50


basically includes at least one and, preferably, a plurality of bodies


52


made of a substantially wearable and sacrificial material. The material of each body


52


may be plastic or any other suitable material.




The bodies


52


are mounted to the outer periphery


38


of the fuel nozzle tip


28


of each burner


14


for the gas turbine combustor


10


. In view that the tip


28


of the fuel nozzle


22


extends through the opening


18


of the annular collar


20


attached to the combustion chamber liner


16


and is disposed radially inwardly therefrom, the bodies


52


are disposed between the annular collar


20


of the liner


16


and the outer periphery


38


of the fuel nozzle tip


28


and space the fuel nozzle tip


28


from the liner collar


20


.




The bodies


52


of sacrificial material will prevent the fuel nozzle tip


28


from contacting the liner collar


20


during assembling of the fuel nozzle


22


into the liner


16


. The bodies


52


will wear away at least partially, and preferably substantially, upon initial operation of the combustor


10


such that the bodies


52


will reduce contact with the liner collar


20


during further operation of the combustor


10


and the fuel nozzle tip


28


will remain spaced from and out of contact with the liner collar


20


during operation of the combustor


10


. The immediate wearing away of the bodies


52


upon operation of the combustor


10


is desirable to achieve an optimum level of performance of the device


50


. The immediate wearing away may occur as melting or any other suitable type of disintegration of the bodies


52


to achieve removal of the bodies


52


from the fuel nozzle tip


28


of the burner


14


.




If only one body


52


is provided, it may have a substantially annular configuration and extend around the outer periphery


38


of the fuel nozzle tip


28


of the burner


14


, as shown in

FIGS. 4 and 5

. The one body


52


may be in the form of a brazed bead


54


as seen in

FIGS. 4 and 5

, or a brazed tape


56


as seen in

FIG. 6

, or a wire


58


as seen in FIG.


7


. If a plurality of bodies


52


are provided, as is preferred, they are spaced apart from one another and, preferably, are spaced equal distances apart from one another, as shown in

FIGS. 5

to


7


. The bodies


52


can number six or are of any other suitable number. Each of the bodies


52


may also be in the form of the brazed bead


54


, tape


56


or wire


58


. The bodies


52


preferably have substantially the same sizes, but need not be so limited.




The device


50


is a temporary solution which allows the fuel nozzle flange


26


of the burner


14


to be bolted to the combustor cover


34


so as to maintain a centered assembly in the process. The bodies


52


of the device


50


will wear away to achieve substantial disintegration thereof such that any contact between the fuel nozzle tip


28


of the burner


14


and the liner collar


20


of the main combustion chamber


12


is very limited in duration or nonexistent during steady state operation of the gas turbine.




The method for centering the fuel nozzle


22


of the burner


14


of the gas turbine combustor


10


includes the steps of providing at least one and, preferably, the plurality of bodies


52


made of the substantially wearable and sacrificial material, mounting the bodies


52


to the outer periphery


38


of the tip


28


of the fuel nozzle


22


of the burner


14


for the gas turbine combustor


10


, assembling the fuel nozzle


22


of the burner


14


into the liner


16


of the main combustion chamber


12


of the combustor


10


, and preventing the fuel nozzle tip


28


of the burner


14


from coming into contact with the collar


20


of the liner


16


of the main combustion chamber


12


during the assembling step by the bodies


52


contacting the liner collar


20


of the main combustion chamber


12


and spacing the fuel nozzle tip


28


of the burner


14


from the liner collar


20


of the main combustion chamber


12


. The fuel nozzle centering method also includes the step of wearing away the bodies


52


at least partially and, preferably, substantially upon initial operation of the gas turbine combustor


10


such that the bodies


52


will reduce contact with the liner collar


20


of the main combustion chamber


12


during further operation of the combustor


10


and the fuel nozzle tip


28


of the burner


14


will remain spaced from and out of contact with the liner collar


20


of the main combustion chamber


12


during operation of the combustor


10


.




It is thought that the present invention and its advantages will be understood from the foregoing description and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely preferred or exemplary embodiment thereof.



Claims
  • 1. A gas turbine combustor, comprising:a main combustor chamber having a liner and an annular collar mounted to said liner so as to define an opening therethrough; at least one burner attached to said main combustor chamber and having a fuel nozzle mounted adjacent to said liner and a tip of said fuel nozzle disposed through said opening of said annular collar of said main combustor chamber with an outer periphery of said tip disposed within and adjacent to said annular collar; and a fuel nozzle centering device mounted to said outer periphery of said tip of said fuel nozzle and disposed between said outer periphery of said fuel nozzle tip and said annular collar of said liner, said device including a sacrificial body of material contacting said liner collar and spacing said fuel nozzle tip radially inwardly from said liner collar such that said fuel nozzle tip is prevented from contacting said liner collar during assembling of said fuel nozzle of said burner to said liner of said main combustion chamber, said sacrificial body of material being at least partially wearable away upon initial operation of said gas turbine combustor such that said sacrificial body of material will diminish in quantity and thereby reduce contact with said liner collar during further operation of said gas turbine combustor so that said fuel nozzle tip will remain spaced from and substantially out of contact with said liner collar of said main combustion chamber during continued operation of said gas turbine combustor.
  • 2. The combustor of claim 1 in which said body of sacrificial material has a substantially annular configuration and extends around said outer periphery of said fuel nozzle tip of said burner.
  • 3. The combustor of claim 1 in which said body of sacrificial material is in the form of a bead.
  • 4. The combustor of claim 1 in which said body of sacrificial material is in the form of tape.
  • 5. The combustor of claim 1 in which said body of sacrificial material is in the form of a wire.
  • 6. A gas turbine combustor, comprising:a main combustor chamber having a liner with an upstream end and an annular collar mounted to said upstream end of said liner so as to define an opening therethrough; at least one burner attached to said main combustor chamber and having a fuel nozzle mounted adjacent to said upstream end of said liner, said fuel nozzle having a tip disposed through said opening of said annular collar of said main combustor chamber with an outer periphery of said tip disposed within and adjacent to said annular collar; and a fuel nozzle centering device mounted to said outer periphery of said tip of said fuel nozzle of said burner and disposed between said outer periphery of said fuel nozzle tip and said annular collar of said liner, said fuel nozzle centering device including a plurality of sacrificial bodies of material contacting said collar of said liner and spacing said fuel nozzle tip radially inwardly from said liner collar such that said fuel nozzle tip is prevented from contacting said liner collar of said main combustion chamber during assembling of said fuel nozzle of said burner to said liner of said main combustion chamber, said sacrificial bodies of material being at least partially wearable away upon initial operation of said gas turbine combustor such that said sacrificial bodies of material will diminish in quantity and reduce contact with said liner collar during further operation of said gas turbine combustor so that said fuel nozzle tip will remain spaced from and out of contact with said liner collar of said main combustion chamber during continued operation of said gas turbine combustor.
  • 7. The combustor of claim 6 in which said bodies have substantially the same sizes.
  • 8. The combustor of claim 6 in which said bodies are spaced apart from one another.
  • 9. The combustor of claim 6 in which said bodies are spaced apart equal distances from one another.
  • 10. The combustor of claim 6 in which each of said bodies is in the form of a bead.
  • 11. The combustor of claim 6 in which each of said bodies is in the form of tape.
  • 12. The combustor of claim 6 in which each of said bodies is in the form of a wire.
  • 13. A method for centering a fuel nozzle of a burner in a gas turbine combustor, the method comprising the steps of:providing at least one body of a substantially wearable and sacrificial material; mounting the body to an outer periphery of a tip of a fuel nozzle of a burner for a gas turbine combustor; assembling the fuel nozzle of the burner to a liner of a main combustion chamber of the gas turbine combustor with the tip of the fuel nozzle extending through an opening of an annular collar attached to the liner; and preventing the fuel nozzle tip of the burner from coming into contact with the annular collar of the liner of the main combustion chamber during the assembling step by the body of sacrificial material contacting the liner collar of the main combustion chamber and spacing the fuel nozzle tip of the burner from the liner collar.
  • 14. The method of claim 13 in which the providing step includes providing a plurality of bodies of a substantially wearable and sacrificial material.
  • 15. The method of claim 14 further comprising the step of:wearing away the bodies at least partially upon initial operation of the gas turbine combustor such that the bodies will reduce contact with the liner collar of the main combustion chamber during further operation of the gas turbine combustor while the fuel nozzle tip of the burner will remain spaced from and out of contact with the liner collar of the main combustion chamber during operation of the gas turbine combustor.
  • 16. The method of claim 13 further comprising the step of:wearing away the body at least partially upon initial operation of the gas turbine combustor such that the body will reduce contact with the liner collar of the main combustion chamber during further operation of the gas turbine combustor while the fuel nozzle tip of the burner will remain spaced from and out of contact with the liner collar of the main combustion chamber during operation of the gas turbine combustor.
US Referenced Citations (6)
Number Name Date Kind
3853273 Bahr et al. Dec 1974
4656713 Rosa et al. Apr 1987
5408830 Lovett Apr 1995
5471840 Lovett Dec 1995
5518395 Maughan May 1996
5676538 Lovett Oct 1997