Catalytic combustor cooling tube vibration dampening device

Information

  • Patent Grant
  • 6662564
  • Patent Number
    6,662,564
  • Date Filed
    Thursday, September 27, 2001
    23 years ago
  • Date Issued
    Tuesday, December 16, 2003
    21 years ago
Abstract
A dampening device for suppressing vibrations of a tube assembly in a catalytic combustor which includes, a plurality of closely oriented, parallel tubes with each tube having at least one expanded region and at least one narrow region. The expanded regions being structured to contact at least one adjacent tube, thus providing support and minimizing degradation of the joint connecting the tubes to the tube sheet, and degradation of the tubes themselves. Such degradation can result from vibration due to flow of cooling air inside of the tubes, flow of the fuel/air mixture passing over the tubes transverse and longitudinal to the tube bundle, and/or other system/engine vibrations.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




This invention relates to a catalytic combustor for a combustion turbine and, more specifically, to a device for suppressing vibration in the plurality of cooling tubes which pass through the fuel/air mixture plenum within a catalytic combustor.




2. Background Information




Combustion turbines, generally, have three main assemblies: a compressor assembly, a combustor assembly, and a turbine assembly. In operation, the compressor compresses ambient air. The compressed air flows into the combustor assembly where it is mixed with a fuel. The fuel and compressed air mixture is ignited creating a heated working gas. The heated working gas is expanded through the turbine assembly. The turbine assembly includes a plurality of stationary vanes and rotating blades. The rotating blades are coupled to a central shaft. The expansion of the working gas through the turbine section forces the blades, and therefore the shaft, to rotate. The shaft may be connected to a generator.




Typically, the combustor assembly creates a working gas at a temperature between 2,500 to 2,900 degrees Fahrenheit (1371 to 1593 degrees centigrade). At high temperatures, particularly above about 1,500 degrees centigrade, the oxygen and nitrogen within the working gas combine to form the pollutants NO and NO


2


, collectively known as NOx. The formation rate of NOx increases exponentially with flame temperature. Thus, for a given engine working gas temperature, the minimum NOx will be created by the combustor assembly when the flame is at a uniform temperature, that is, there are no hot spots in the combustor assembly. This is accomplished by premixing all of the fuel with all of the of air available for combustion (referred to as low NOx lean-premix combustion) so that the flame temperature within the combustor assembly is uniform and the NOx production is reduced.




Lean pre-mixed flames are generally less stabile than non-well-mixed flames, as the high temperature/fuel rich regions of non-well-mixed flames add to a flame's stability. One method of stabilizing lean premixed flames is to react some of the fuel/air mixture in conjunction with a catalyst prior to the combustion zone. To utilize the catalyst, a fuel/air mixture is passed over a catalyst material, or catalyst bed, causing a pre-reaction of a portion of the mixture and creating radicals which aid in stabilizing combustion at a downstream location within the combustor assembly.




Prior art catalytic combustors completely mix the fuel and the air prior to the catalyst. This provides a fuel lean mixture to the catalyst. However, with a fuel lean mixture, typical catalyst materials are not active at compressor discharge temperatures. As such, a preburner is required to heat the air prior to the catalyst adding cost and complexity to the design as well as generating NOx emissions, See e.g., U.S. Pat. No. 5,826,429. It is, therefore, desirable to have a combustor assembly that burns a fuel lean mixture, so that NOx is reduced, but passes a fuel rich mixture through the catalyst bed so that a preburner is not required. The preburner can be eliminated because the fuel rich mixture contains sufficient mixture strength, without being preheated, to activate the catalyst and create the necessary radicals to maintain a steady flame, when subjected to compressor discharge temperatures. As shown in U.S. patent application Ser. No.


09-670,035,


which is incorporated by reference, this is accomplished by splitting the flow of compressed air through the combustor. One flow stream is mixed with fuel, as a fuel rich mixture, and passed over the catalyst bed. The other flow stream may be used to cool the catalyst bed.




One disadvantage of using a catalyst is that the catalyst is subject to degradation when exposed to high temperatures. High temperatures may be created by the reaction between the catalyst and the fuel, pre-ignition within the catalyst bed, and/or flashback ignition from the downstream combustion zone extending into the catalyst bed. Prior art catalyst beds included tubes. These tubes were susceptible to vibration because they were cantilevered, being connected to a tube sheet at their upstream ends. The inner surface of the tubes were free of the catalyst material and allowed a portion of the compressed air to pass, unreacted, through the tubes. The fuel/air mixture passed over the tubes, and reacted with, the catalyst. Then, the compressed air and the fuel/air mixture were combined. The compressed air absorbed heat created by the reaction of the fuel with the catalyst and/or any ignition or flashback within the catalyst bed. See U.S. patent application Ser. No.


09-670,035.






The disadvantage of such systems is susceptibility of the tubular configuration to vibration damage resulting from: (1) flow of cooling air inside of the tubes, (2) flow of the fuel/air mixture passing over the tubes transverse and longitudinal to the tube bundle, and (3) other system/engine vibrations. Such vibration has caused problems in the power generation field, including degradation of the joint (e.g. braze) connecting the tubes to the tubesheet and degradation of the tubes themselves, both resulting from tube to tube and/or tube to support structure impacting.




There is, therefore, a need for a dampening device for a catalytic reactor assembly of a combustion turbine, which suppresses vibration of the plurality of closely oriented parallel tubes.




There is further a need for a dampening device for a catalytic reactor assembly to effectively baffle and promote even distribution of the fuel/air mixture.




There is further a need for a dampening device for a catalytic reactor assembly that provides a stronger, reinforced attachment of the tubes to the tubesheet.




There is further a need for a dampening device for a catalytic reactor assembly that provides resistance to reverse flow of the fuel/air mixture caused by eddie currents, which in turn can lead to backflash (premature ignition of the fuel in the combustor).




There is further a need for a dampening device for a catalytic reactor assembly that maintains appropriate pressure differential to promote uniform distribution of the fuel/air mixture and ensure adequate cooling is maintained.




SUMMARY OF THE INVENTION




The present invention satisfies these needs, and others, by providing a dampening device with expanded regions on the tubes that maintain tube to tube contact and thus suppress vibration. The invention consists of at least one expanded region and at least one narrow region on each tube. The expanded region may be achieved by a localized increase in the nominal tube circumference, a sleeve or furrel placed over the tube and enlarging the circumference, or by machining or swaging the tube to create narrow regions. The localized expansions extend for a portion of the tube length, having a gradual transition between the nominal circumference and the center of expansion. If the tube is cut or swaged to create narrow regions in between the nominal tube circumference regions, the nominal tube circumference would serve as the expanded region. There may also be multiple expanded regions on a tube.




The expanded regions may be symmetric along the tube length and/or around the tube circumference. Alternatively, the expansions could be non-symmetric, or even single-sided. Expansions located at the ends of the tubes are examples of single-sided expansions. Moreover, an expanded region on one tube may contact another expanded region on another tube, or alternatively, may be staggered so that an expanded region on one tube contacts the narrow region of an adjacent tube. The tubes and the expanded regions thereon could be a variety of shapes such as bulges, ridges, and/or helices, so long as the flow path around the tubes and desired pressure drop is maintained.




By maintaining tube to tube contact, adjacent tubes support one another rather than impact one another during various modes of vibration. Moreover, expansion of the tubes to provide contact at a plane just downstream of the fuel/air inlet has been predicted analytically to effectively baffle and to promote even distribution of the fuel/air mixture.




The upstream ends of the tubes may be bulged or expanded to provide additional support of the fragile joints (e.g. brazes) where the tubes attach to the tube sheet. Similarly, the tubes may be bulged at their downstream ends to provide resistance to reverse flow and therefore backflash, because eddie currents are eliminated by the gradual bulging profile. The expanded or flared inlet and outlet ends of the tubes also provide a substantial reduction (e.g. approximately 14 percent for a flared inlet, 22 percent for a flared outlet) in pressure differential between the air inside the tubes and the air/fuel mixture passing over them. Avoiding an excessive pressure differential allows more effective cooling.











BRIEF DESCRIPTION OF THE DRAWINGS




A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:





FIG. 1

is a cross sectional view of a combustion turbine.





FIG. 2

is a partial cross sectional view of a combustor assembly shown on FIG.


1


.





FIG. 3

is an isometric view showing modular catalytic cores disposed about a central axis.





FIGS. 4A-4H

are cross sectional, close-up views of the various embodiments of the invention. Each figure shows a different embodiment of two of the many cooling tubes within a catalytic combustor module.

FIG. 4A

is a side view of an embodiment in which symmetric localized expansions on one tube contact the expansions on an adjacent tube.

FIG. 4B

a side view of an embodiment with staggered localized expansions.

FIG. 4C

is a side view of tubes having furrels disposed symmetrically.

FIG. 4D

is a side view of tubes having furrels as staggered localized expansions.

FIG. 4E

is a side view a ridge embodiment in which the ridge is a helix.

FIG. 4F

is a side view of an embodiment with expanded regions of various widths, lengths and heights FIG.


4


F′ is a cross-sectional view taken along line


4


F′—


4


F′ on FIG.


4


F.

FIG. 4G

is an isometric view of a symmetric ridge expansion. FIG.


4


G′ is a cross-sectional view taken along line


4


G′—


4


G′ on FIG.


4


G.

FIG. 4H

is an isometric view of a non-symmetric ridge expansion. FIG.


4


H′ is a cross-sectional view taken along line


4


H′—


4


H′ on FIG.


4


H.





FIG. 5A

shows an isometric view of a furrel that may be used as an expanded region of the tube.





FIG. 5B

shows an isometric view of furrels disposed on the tubes.





FIG. 5C

shows an isometric view of an alternate furrel.





FIG. 5D

is a side view of an alternate furrel.





FIG. 6

is an end view of the invention looking along the longitudinal axis of one of the combustor tube modules.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT




As is well known in the art and shown in

FIG. 1

, a combustion turbine


1


includes a compressor assembly


2


, a catalytic combustor assembly


3


, a transition section


4


, and a turbine assembly


5


. A flow path


10


exists through the compressor


2


, catalytic combustor assembly


3


, transition section


4


, and turbine assembly


5


. The turbine assembly


5


may be mechanically coupled to the compressor assembly


2


by a central shaft


6


. Typically, an outer casing


7


encloses a plurality of catalytic combustor assemblies


3


and transition sections


4


. Outer casing


7


creates a compressed air plenum


8


. The catalytic combustor assemblies


3


and transition sections


4


are disposed within the compressed air plenum


8


. The catalytic combustor assemblies


3


are, preferably, disposed circumferentiality about the central shaft


6


.




In operation, the compressor assembly


2


inducts ambient air and compresses it. The compressed air travels through the flow path


10


to the compressed air plenum


8


defined by casing


7


. Compressed air within the compressed air plenum


8


enters a catalytic combustor assembly


3


where, as will be detailed below, the compressed air is mixed with a fuel and ignited to create a working gas. The working gas passes from the catalytic combustor assembly


3


through transition section


4


and into the turbine assembly


5


. In the turbine assembly


5


the working gas is expanded through a series of rotatable blades


9


which are attached to shaft


6


and the stationary vanes


11


. As the working gas passes through the turbine assembly


5


, the blades


9


and shaft


6


rotate creating a mechanical force. The turbine assembly


5


can be coupled to a generator to produce electricity.




As shown in

FIG. 2

, the catalytic combustor assembly


3


includes a fuel source


12


, a support frame


14


, an igniter assembly


16


, fuel tubes


18


, and a catalytic reactor assembly


20


. The catalytic reactor assembly


20


includes a catalytic core


21


, an inlet nozzle


22


, and an outer shell


24


. The catalytic core


21


includes an inner shell


26


, a tube sheet


28


, a plurality of elongated tubes


30


, and an inner wall


32


. The catalytic core


21


is an elongated toroid which is disposed axially about the igniter assembly


16


. Inner wall


32


is disposed adjacent to igniter assembly


16


. Both the inner shell


26


and the inner wall


32


have interior surfaces


27


,


33


respectively, located within the fuel/air plenum


38


(described below).




Outer shell


24


is in a spaced relation to inner shell


26


thereby creating a first plenum


34


. The first plenum


34


has a compressed air inlet


36


. The compressed air inlet


36


is in fluid communication with an air source, preferably the compressed air plenum


8


. A fuel inlet


37


penetrates outer shell


24


. Fuel inlet


37


is located downstream of air inlet


36


. The fuel inlet


37


is in fluid communication with a fuel tube


18


. The fuel tube


18


is in fluid communication with the fuel source


12


.




A fuel/air plenum


38


is defined by tube sheet


28


, inner shell


26


, and inner wall


32


. There is at least one fuel/air mixture inlet


40


on inner shell


26


, which allows fluid communication between first plenum


34


and fuel/air plenum


38


. The fuel/air plenum


38


has a downstream end


42


, which is in fluid communication with a mixing chamber


44


.




The plurality of tubes


30


each have a first end


46


, a medial portion


47


and a second end


48


. Each tube first end


46


extends through tube sheet


28


and is in fluid communication with inlet nozzle


22


. The tube first ends


46


, which are the upstream ends, are isolated from the fuel inlet


37


. Thus, fuel cannot enter the first end


46


of the tubes


30


. Each tube second end


48


is in fluid communication with mixing chamber


44


. The tubes


30


have an interior surface


29


and an exterior surface


31


. Each tube


30


has at least one expanded region


140


, at least one narrow region


160


and at least one transition region


135


. The narrow region


160


is typically the tube nominal diameter, however, as set forth below, the nominal tube diameter can be the expanded region


140


when the tube


30


is swaged to reduce the diameter in the narrow region


160


. A catalytic material


30




a


may be bonded to the tube outer surface


31


. Possible catalytic materials


30




a


include, but are not limited to, platinum, palladium, rhodium, iridium, osmium, ruthenium or other precious metal based combinations of elements with for example, and not limited to, cobalt, nickel or iron. Additionally, the catalytic material


30




a


may be bonded to the interior surface


27


of inner shell


26


and the interior surface


33


of inner wall


32


. Thus, the surfaces within the fuel/air plenum


38


are, generally, coated with a catalytic material. In the preferred embodiment, the tubes


30


are tubular members. The tubes


30


may, however, be of any shape and may be constructed of members such as plates. The mixing chamber


44


has a downstream end


49


, which is in fluid communication with a flame zone


60


. Flame zone


60


is also in fluid communication with igniter assembly


16


.




The igniter assembly


16


includes an outer wall


17


, which defines an annular passage


15


. The annular passage


15


is in fluid communication with compressed air plenum


8


. The igniter assembly


16


is in further communication with a fuel tube


18


. The igniter assembly


16


mixes compressed air from annular passage


15


and fuel from tube


18


and ignites the mixture initially with either a spark igniter or a igniter flame (not shown). The compressed air in annular passage


15


is swirled by vanes in annular passage


15


. The angular momentum of the swirl causes a vortex flow with a low-pressure region along the centerline of the igniter assembly


16


. Hot combustion products from flame zone


60


are re-circulated upstream along the low-pressure region and continuously ignite the incoming fuel air mixture to create a stabile pilot flame. Alternately, a spark igniter could be used instead of the pilot flame.




In operation, air from an air source, which is fed to the combustor, such as the compressed air plenum


8


, is divided into at least two portions; a first portion, which is about 10 to 20 percent of the compressed air in the flow path


10


, flows through air inlet


36


into the first plenum


34


. A second portion of air, which is about 75 to 85 percent of the compressed air within the flow path


10


, flows through inlet


22


into tubes


30


. A third portion of air, which is about 5 percent of the compressed air in the flow path


10


, may flow through the igniter assembly


16


.




The first portion of air enters the first plenum


34


. Within first plenum


34


the compressed air is mixed with a fuel that enters first plenum


34


through fuel inlet


37


thereby creating a fuel/air mixture. The fuel/air mixture is, preferably, fuel rich. The fuel rich fuel/air mixture passes through fuel/air inlet


40


into the fuel/air plenum


38


. As the fuel rich fuel/air mixture, which is created in first plenum


34


, enters the fuel/air plenum


38


, the fuel/air mixture reacts with the catalytic material disposed on the tube outer surfaces


31


, inner shell interior surface


27


, and inner wall interior surface


33


. The reacted fuel/air mixture exits the fuel/air plenum


38


into mixing chamber


44


.




The second portion of air travels through inlet


22


and enters the tube first ends


46


, traveling through tubes


30


to the tube second end


48


. Air which has traveled through tubes


30


also enters mixing chamber


44


. As the air travels through tubes


30


, it absorbs heat created by the reaction of the fuel/air mixture with the catalytic material. Within mixing chamber


44


, the reacted fuel/air mixture and compressed air is further mixed to create a fuel lean pre-ignition gas. The fuel lean pre-ignition gas exits the downstream end of the mixing chamber


49


and enters the flame zone


60


. Within flame zone


60


the fuel lean pre-ignition gas is ignited by ignition assembly


16


thereby creating a working gas.




As shown in

FIG. 3

, for ease of construction the catalytic reactor assembly may be separated into modules


50


that are disposed about a central axis


100


. Each module


50


includes inner shell


26




a,


an inner wall


32




a


and sidewalls


52


,


54


. A plurality of tubes


30


are enclosed by inner shell


26




a,


inner wall


32




a


and sidewalls


52


,


54


. Each module


50


also has a tube sheet


28




a,


an outer shell


24




a


and a fuel inlet


37




a.


The rhomboid tube sheet


28




a


is coupled to the inner shell


26




a,


inner wall


32




a


and sidewalls


52


,


54


of the upstream end of the module


50


by a fastening process (e.g. brazing). The tube sheet


28


is segmented, supporting a plurality of tubes


30


passing therethrough at the tubes


30


upstream ends


46


. As shown, six modules


50


form a generally hexagonal shape about the central axis


100


. Of course, any number of modules


50


of various shapes could be used.




The use of the catalytic material


30




a


allows a controlled reaction of the rich fuel/air mixture at a relatively low temperature such that almost no NOx is created in fuel/air plenum


38


. The reaction of a portion of the fuel and air preheats the fuel/air mixture which aids in stabilizing the downstream flame in flame zone


60


. When the fuel rich mixture is combined with the air, from the second portion of compressed air, a fuel lean pre-ignition gas is created. Because the pre-ignition gas is fuel-lean, the amount of NOx created by the combustor assembly


3


is reduced. Because compressed air only travels through the tubes


30


, there is no chance that a fuel air mixture will ignite within the tubes


30


. Thus, the tubes


30


will always be effective to remove heat from the fuel/air plenum


38


thereby extending the working life of the catalytic material


30




a.






A vibration dampening device


120


, shown in

FIGS. 4A-4G

, consists of at least one expanded region


140


and at least one narrow region


160


on one or more of the tubes


30


. The narrow region


160


, in most of the embodiments, is simply the unexpanded part of the tube or the nominal tube circumference. The expanded region


140


permits the plurality of closely oriented and parallel tubes


30


to remain in contact with one another, thus suppressing vibration. At least one expanded region


140


on each tube


30


is located on the tube medial portion


47


.




The expanded regions


140


may be formed numerous ways, including but not limited to, a localized expansion


130


of the nominal tube circumference with a gradual transition region


135


between the nominal tube circumference and the center of expansion, as shown in

FIG. 4A

; a sleeve or furrel


130




a


placed over the tube


30


, thus enlarging the circumference as shown in

FIG. 4C

; or by using the nominal circumference as the expanded region


140


after machining or swaging the tube


30


to remove tube material and create narrow regions


160


. The expanded region


140


does not extend the entire length of the tube


30


but there may be more than one expanded region


140


on each tube


30


. As discussed in more detail below, the expanded region


140


may be symmetric


230


(

FIG. 4G

) along the tube length and/or around the tube circumference. Alternatively, the expansions could be non-symmetric


330


, single-sided expansions


430


(FIG.


4


H), or any combination thereof. The catalyst material


30




a


may cover the entire tube


30


or only the narrow regions


160


, in which case the contacting expanded regions


140


are not coated.




As shown in

FIG. 4A

, in one embodiment, each tube


30


has an expanded region


140


at its first end


46


, which is the upstream end of the tube


30


, at least one expanded region


140


at the tube medial portion


47


and an expanded region


140


at it's second end


48


, which is the downstream end of the tube


30


. The upstream end


46


expanded region


140


help provide additional strength and support at the vibration susceptible tube sheet


28


junctions between the tubes


30


and the inner shell


26


, inner wall


32


, and side walls


52


,


54


. At the point where the tubes


30


pass through the tube sheet


28


, the expanded regions


140


do not contact each other. That is, to allow the tube sheet


28


to be contiguous, the expanded regions


140


are spaced from each other at the tube sheet


28


. Both expanded region


140


located at the first end and the second end


46


,


48


also help to generate the desired flow path around the tubes


30


and the desired minimal pressure drop within the module


50


.




In this embodiment, the expanded regions


140


are localized expansions


130


of the nominal outside tube circumference. The localized expansions


130


have at least one transition region


135


, forming a gradual angle between the nominal outside tube circumference and the center of the expanded region


140


. The gradual transition


135


and subtle expansion profile


130


are necessary to promote even flow through the module


50


and prevent an excessive pressure drop. An abrupt transition


135


and/or expansion


140


would likely create eddie currents which have damaging consequences such as back flash. The tubes


30


upstream ends


46


and downstream ends


48


are both expanded and each of the expanded regions


140


of one tube


30


contact the expanded regions


140


of the adjacent tubes


30


. The catalyst


30




a


is only covering the unexpanded or narrow regions


160


of the tube


30


. A flow path


138


, corresponding to the fuel/air plenum


38


, exists between the adjacent tubes


30


. The flow path


138


is structured to avoid excessive pressure drop within, and promote uniform flow through the module


50


.




In another embodiment, shown in

FIG. 4B

, the localized expansions


130


of one tube


30


are staggered with respect to the localized expansions


130


of at least one other, adjacent tube


30


, so that the narrow region


160


of one tube contacts the localized expansion


130


of the adjacent tube


30


. In this embodiment a different flow path


138


is created. As shown in

FIG. 4B

, the flow path


138


gaps are smaller but more numerous. However, the same beneficial uniform flow and minimal pressure drop can be achieved. Additionally, all of the tubes


30


do not have the same expansion pattern. As seen in

FIG. 4B

, every other tube does not have expansions


140


at the upstream


46


and downstream


48


ends. The end expansion


140


on one tube


30


supports the nominal tube circumference or narrow region


160


, of the adjacent tube


30






In another embodiment, shown in

FIGS. 4C

,


4


D,


5


A,


5


B, and


5


C, a furrel


130




a


is disposed over the tube


30


, thus creating an expanded region


240


. A furrel


130




a


is a separate sleeve or piece of material having a greater outside diameter than the nominal diameter of the tube


30


. As shown in

FIG. 5A

, the furrels


130




a


may be various lengths and shapes as long as a flow path


138


is formed between the expanded regions


240


. The furrels


130




a


may be held in place on the tube


30


by any commonly used fastening means such as brazing, or a setscrew


131


(FIGS.


5


C and


5


D). The preferred furrel


130




a


shape, shown in

FIG. 5A

, is a sleeve tapered on both sides to form a gradual transition region


135


between the tube nominal circumference and the region with the greatest diameter on the furrel


130




a


. As shown in

FIG. 5C

, the furrel


130




a


may be formed without a transition. As before, the catalyst material


30




a


may cover the entire tube


30


or only the narrow regions


160


, and the furrels


130




a


of one tube


30


may contact the furrels


130




a


of the adjacent tubes


30


as shown in

FIG. 4C

or they may be staggered as shown in FIG.


4


D.





FIGS. 4E-4G

show another embodiment in which the expanded regions


140


comprise a narrow ridge


340


expansion, extending longitudinally along the tube


30


and extending radially beyond the nominal diameter of the tube


30


. As shown in

FIG. 4E

, the ridge


340


may form a helix


330


A as it wraps around the tube


30


. The helix


330


A would touch the helix


330


A of the adjacent tubes


30


, thus providing support. Moreover, the helix shape


330


A may enhance the flow path


138


around the tubes


30


and through the module


50


to improve catalytic reaction and achieve the best balance of fuel/air mixture combining with the cooling air exiting the tubes


30


at the downstream ends


48


. Alternatively, as shown in

FIGS. 4F

,


4


F′,


4


G, and


4


H the ridge


330


B may be generally straight, that is, extending in a direction parallel to, but spaced from, the tube axis. The ridges


330


B may have various lengths, widths and heights. Additionally, the ridges


330


B may be disposed at various locations around the circumference of the tubes


30


. FIGS.


4


G and


4


G′ illustrates symmetric ridges


330


B, with the ridges


330


B spaced generally 90 degrees apart around the circumference of the tube


30


. FIGS.


4


H and


4


H′ show non-symmetric ridges


330


C wherein the ridge


330


C is located on one side of the tube


30


.

FIG. 4H

also shows varying the pattern of the expanded region


340


depending on the tube


30


location within the module


50


. That is, ridge


330


D is configured for a tube


30


located in a corner of a module


50


, where for example the inner shell


26


and one of the side walls


52


connect. Various tube


30


size, shape, location and symmetry combinations could be utilized to benefit from the best amalgamation of tube


30


support, module


50


flow rate, and pressure drop within the module


50


.




As

FIG. 6

shows the tubes


30


in a module


50


. The expanded regions


140


contact each other where the tubes


30


are adjacent to other tubes


30


, or contact the interior shell surface


27


or inner wall surface


33


where the tubes


30


are located adjacent to either the interior shell


26


or inner wall


32


. The tubes


30


support each other and therefore reduce vibration. The fuel/air mixture flows past the expanded regions


140


through the plenum gaps constituting the flow path


138


and then combines with the cooling air exiting the tubes


30


at the tube downstream ends


48


.

FIG. 5

shows the medial portion of the module


50


, looking down the longitudinal tube axis, of the embodiment in which the expansions


140


are localized tube expansions


130


of the nominal tube circumference.




While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. For example, although the tubes


30


have been shown to be circular, various shapes could be used. For example the tubes could be oval or any other shape so long as the contacting surfaces preserve a flow path


138


for the fuel rich mixture to traverse and the benefit of minimal pressure drop is sustained. Accordingly, the particular arrangements disclosed, are meant to be illustrative only and not limiting as to the scope of invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.



Claims
  • 1. A dampening device for suppressing vibrations of a tube assembly in a catalytic combustor, said dampening device comprising:a plurality of proximate, elongated, parallel tubes; each tube of said plurality of tubes having a first end, a medial portion, a second end, at least one expanded region on said medial portion, and at least one narrow region; and each said expanded region being structured to contact at least one adjacent tube.
  • 2. The dampening device of claim 1, wherein said at least one expanded regions are localized expansions of the tube circumference, said localized expansions having at least one gradual transition region between the nominal outside tube circumference and said expanded region.
  • 3. The dampening device of claim 1 wherein said at least one expanded regions have a greater circumference than the nominal tube circumference.
  • 4. The dampening device of claim 1 wherein:said at least one expanded regions include a furrel disposed over said tube; and said furrel having a circumference greater than the nominal tube circumference.
  • 5. The dampening device of claim 1 wherein said at least one expanded regions include at least one longitudinal ridge extending beyond the nominal tube circumference.
  • 6. The dampening device of claim 5 wherein:said at least one ridge includes a plurality of ridges; said plurality of ridges being symmetric.
  • 7. The dampening device of claim 5 wherein:said at least one ridge includes a plurality of ridges; said plurality of ridges being non-symmetric.
  • 8. The dampening device of claim 1 wherein at least said at least one narrow region of said plurality of tubes is coated with a catalyst, said catalyst being selected from the group consisting of platinum, palladium, rhodium, iridium, osmium, ruthenium, cobalt, nickel and iron.
  • 9. A tube module for a catalytic combustor comprising:a plurality of proximate, elongated parallel cooling tubes; said tubes each having a first end, a medial portion, and a second end; a tube sheet; a shell coupled to said tube sheet thereby defining a plenum; said tubes coupled to said tube sheet with said first ends passing through said tube sheet, said tube medial portion extending through said plenum; and a dampening assembly for suppressing vibration of said plurality of tubes comprising at least one expanded region, disposed on said tube medial portion, and at least one narrow region on each tube, said at least one expanded region being structured to contact at least one adjacent tube.
  • 10. The dampening device of claim 9, wherein said at least one expanded regions are localized expansions of the tube circumference, said localized expansions having at least one gradual transition region between the nominal outside tube circumference and said expanded region.
  • 11. The dampening device of claim 9 wherein said at least one expanded region have a greater circumference than the nominal tube circumference.
  • 12. The dampening device of claim 9 wherein:said at least one expanded regions include a furrel disposed over said tube; and said furrel having a circumference greater than the nominal tube circumference.
  • 13. The dampening device of claim 9 wherein said at least one expanded regions include at least one longitudinal ridge extending beyond the nominal tube circumference.
  • 14. The tube module of claim 9 wherein said at least one narrow region of said plurality of tubes is coated with a catalyst, said catalyst being selected from the group consisting of platinum, palladium, rhodium, iridium, osmium, ruthenium, cobalt, nickel and iron.
  • 15. A combustion turbine comprising:a compressor assembly; a turbine assembly; a catalytic combustor assembly; wherein said catalytic combustor assembly includes: an air source; a fuel delivery means; a said catalytic combustor assembly in fluid communication with said air source and fuel delivery means, and having a fuel/air plenum which is coated with a catalytic material; said fuel/air plenum having a plurality of proximate, parallel elongated cooling air tubes passing therethrough, said tubes each having a first end, a medial portion, and a second end, and a means for suppressing vibration of said plurality of cooling tubes having at least one expanded region, disposed on said tube medial portion, and at least one narrow region on each said tube, said at least one expanded region being structured to contact at least one adjacent tube; said tube first ends being in fluid communication with said air source and isolated from said fuel delivery means; and a means for igniting a fuel/air mixture.
  • 16. The dampening device of claim 15, wherein said at least one expanded regions are localized expansions of the tube circumference, said localized expansions having at least one gradual transition region between the nominal outside tube circumference and said expanded region.
  • 17. The dampening device of claim 15 wherein said at least one expanded region have a greater circumference than the nominal tube circumference.
  • 18. The dampening device of claim 15 wherein:said at least one expanded region includes a furrel disposed over said tube; and said furrel having a circumference greater than the nominal tube circumference.
  • 19. The dampening device of claim 15 wherein said at least one expanded regions include at least one longitudinal ridge extending beyond the nominal tube circumference.
  • 20. The combustion turbine of claim 15 wherein at least said at least one narrow region of said plurality of tubes is coated with a catalyst, said catalyst being selected from the group consisting of platinum, palladium, rhodium, iridium, osmium, ruthenium, cobalt, nickel and iron.
US Referenced Citations (3)
Number Name Date Kind
3718426 Harris Feb 1973 A
6174159 Smith et al. Jan 2001 B1
6415608 Newburry Jul 2002 B1
Foreign Referenced Citations (1)
Number Date Country
1915304 Oct 1969 DE