REMOVABLE SWIRLER ASSEMBLY FOR A COMBUSTION LINER

Abstract

A novel and improved swirler assembly for use in a combustion liner of a gas turbine engine is disclosed. The swirler assembly is removable and sized to provide an improved assembly, repairability, and fit-up in the combustion liner. The swirler assembly includes a premix tube, premix swirler and a plurality of axially spaced mounting blocks for receiving removable fasteners for securing the swirler assembly to the combustor.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application Ser. No. 61/815,835, filed on Apr. 25, 2013. This application is related by subject matter to commonly-assigned U.S. Non-Provisional patent applications entitled PREMIXER ASSEMBLY FOR GAS TURBINE COMBUSTOR (Attorney Docket No. PSM-317/PSSF.199281) and SWIRLER ASSEMBLY AND STIFFENING MECHANISM FOR PREMIXER ASSEMBLY OF A GAS TURBINE COMBUSTOR (Attorney Docket No. PSM-318/PSSF.199282) and assigned to the same assignee as the present application.

TECHNICAL FIELD

The present invention generally relates to a gas turbine combustor. More specifically, the present invention is directed towards a removable swirler portion of combustion liner having features designed to enhance combustor performance and increase component life through improved assembly and disassembly techniques and improved cooling configurations.

BACKGROUND OF THE INVENTION

In a typical gas turbine engine, a compressor having alternating stages of rotating and stationary airfoils is coupled to a turbine through an axial shaft, with the turbine also having alternating stages of rotating and stationary airfoils. The compressor stages decrease in size in order to compress the air passing therethrough. The compressed air is then supplied to one or more combustors, which mixes the air with fuel. An ignition source proximate the one or more combustors ignite the mixture, forming hot combustion gases. The expansion of the hot combustion gases drives the stages of a turbine, which is coupled to the compressor through an axial shaft. The exhaust gases can then be used as a source of propulsion, to generate steam through a heat recovery steam generator, or in powerplant operations to turn a shaft coupled to a generator for producing electricity.

The combustion system of a gas turbine engine can take on a variety of configurations. A combustion system for a gas turbine engine can comprise a single combustion chamber, a plurality of individual combustion chambers spaced about the axis of the engine, a plenum-type combustion system, or a variety of other combustion systems. Depending on the engine geometry, performance requirements, and physical operating location, the exact combustor arrangement will vary.

One such combustion system comprises a casing secured to the frame of the engine, a combustion liner secured within at least a part of the casing, and one or more fuel nozzles positioned within or adjacent to the combustion liner for injecting a fuel (gas, liquid, or both) into the combustion chamber. The combustion system is in fluid communication with the engine. More specifically, the casing and liner arrangement provides a way for air from the compressor to enter the combustion system, where it mixes with fuel from the one or more fuel nozzles. The fuel-air mixture is ignited by an ignition source, such as a spark igniter. Hot combustion gases travel through the combustion liner and often through one or more transition pieces and into the turbine. The transition piece is essentially a duct having a geometry that changes from the shape of the combustor to the inlet of the turbine.

The combustion liner is at the center of combustor operations. The combustion liner geometry is dictated by a variety of factors including the operating parameters of the engine, performance requirements, and available geometry. While combustion liner geometries can vary, the combustion liner typically includes at least a portion for receiving fuel nozzles, for mixing fuel and air together and for containing the reaction when the fuel and air mixture is ignited.

Combustion liners of the prior art have met certain performance requirements, but have also exhibited various shortcomings. For example, prior combustion liners have been primarily or exclusively welded assemblies, thereby making it difficult for operators or repair facilities to access all of the features of the combustion liner to be repaired. Furthermore, prior combustor designs of similar structure were capable of operating approximately 8,000 hours prior to refurbishment or replacement. In an effort to improve gas turbine engine efficiency, there is a strong desire in the operator community to be able to extend the timeframe between repairs, so as to reduce engine downtime and repair/overhaul costs.

SUMMARY

In accordance with the present invention, there is provided a novel and improved swirler assembly for use in a combustion liner of a gas turbine engine. The swirler assembly is removable and sized to provide an improved assembly, repairability, and fit-up in the combustion liner. A plurality of main swirler assemblies are located in a combustion liner about a central axis and sized to receive a plurality of fuel nozzles.

In accordance with an embodiment of the present invention, there is provided a swirler assembly for a gas turbine combustor comprising a premix tube, a premix swirler positioned within the premix tube, a first mounting block positioned along an outer wall of the premix tube proximate an inlet end and having a plurality of first holes, and a second mounting block also positioned along the outer wall of the premix tube, the second mounting block spaced a distance from the first mounting block and having one or more second holes perpendicular to the plurality of first holes.

In accordance with another embodiment of the present invention, there is provided a multi-point, multi-directional fastening assembly for use in a gas turbine combustor comprising a first mounting block secured to a body with the first mounting block having a forward face, an opposing aft face, generally parallel side faces, an arc-shaped outer face and a plurality of holes located in the arc-shaped outer face. The fastening assembly also comprises a second mounting block secured to the body and having one or more holes, where the plurality of holes in the first mounting block are oriented generally perpendicular to the one or more holes in the second mounting block.

In accordance with yet another embodiment of the present invention there is provided a removable swirler assembly in a combustor comprising a generally cylindrical body, a center core and a plurality of vanes extending between the center core and the generally cylindrical body. The removable swirler assembly also comprises a first mounting block secured to the generally cylindrical body where the first mounting block having a forward face, an opposing aft face, generally parallel side faces, an arc-shaped outer face and a plurality of holes located in the arc-shaped outer face. The removable swirler assembly also comprises a second mounting block secured to the body and having one or more holes, where the removable swirler is fastened to the combustor at both the first and second mounting blocks through a plurality of removable fasteners.

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 instant invention will now be described with particular reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The present invention is described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 is a partial cross section view of a gas turbine engine of the prior art in which a combustion system in accordance with an embodiment of the present invention is capable of being used;

FIG. 2 is a cross section view of a gas turbine combustor of the prior art capable of operating within the gas turbine engine of FIG. 1;

FIG. 3 is a perspective view of a combustion liner incorporating an embodiment of the present invention;

FIG. 4 is a cross section view of a combustion liner incorporating an embodiment in accordance with an embodiment of the present invention;

FIG. 5 is an alternate view of the cross section of FIG. 4, incorporating an embodiment of the present invention;

FIG. 6 is a cross section view of a combustion liner taken through the swirler assembly in accordance with an embodiment of the present invention;

FIG. 7 is an alternate view of the cross section of FIG. 6, in accordance with an embodiment of the present invention;

FIG. 8 is a perspective view of a swirler assembly portion of the combustion liner of FIG. 3 in accordance with an embodiment of the present invention;

FIG. 9 is a detailed cross section view taken through an inlet portion of the combustion liner of FIG. 3 including a cross section of the swirler assembly in accordance with an embodiment of the present invention; and,

FIG. 10 is a partial cross section view of the swirler assembly of the combustion liner in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION

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 FIG. 1, a gas turbine engine 100 of the prior art is depicted in partial cross section. The gas turbine engine 100 generally comprises an outer casing 102, enveloping the main portions of the engine. A shaft 104 extends axially along an engine axis A-A and is coupled to a compressor 106 and a turbine 108. The compressor 106 receives air through inlet region 110 and directs the air through alternating rows of rotating and stationary airfoils of decreasing size in order to compress the air as it passes therethrough, thereby increasing the temperature and pressure of the air. The compressed air is then directed through one or more combustion systems 112 where fuel and air are mixed together and ignited to form hot combustion gases. The hot combustion gases are then directed into the turbine 108 and through alternating rows of rotating and stationary airfoils of increasing size, so as to expand the fluid and convert the energy of the combustion gases into mechanical work to drive the shaft 104. The shaft 104 may also be coupled to a shaft of an electrical generator for purposes of generating electricity (not shown).

FIG. 2 discloses a cross section of a combustor 200 of a gas turbine engine of the prior art. As such, this typical gas turbine combustor 200 comprises a casing 202, a cover 204, one or more fuel injectors 206, and a combustion liner 208. A transition piece 210 connects the combustion liner 208 to an inlet of the turbine 212.

The present invention is shown in detail in FIGS. 3-10 and discloses a new and improved removable swirler assembly for use in a combustor of a gas turbine engine. Referring initially to FIGS. 3-7, a combustion liner 300 having a removable swirler assembly 332 is disclosed. The combustion liner 300 comprises a generally cylindrical liner body 302 having an inlet end 304, an outlet end 306, or discharge end, and an axis B-B extending through the combustor. The combustion liner 300 is generally cylindrical in cross section, but it is understood that the combustion liner 300 can vary in shape, have tapered sections, or sections of varying diameter. The combustion liner 300 is generally fabricated from rolled sheet metal that is welded along an axial seam and can be formed or expanded into a modified cylindrical structure depending on the specific combustion geometry. The combustion liner 300 is preferably manufactured from a high temperature alloy, such as Haynes 230, capable of withstanding elevated combustor conditions upwards of approximately 1500 deg Fahrenheit. Alternate materials can be used such as Hastelloy-X or Inconel.

The combustion liner 300 further comprises an inlet ring basket 308 secured to the generally cylindrical body 302. The inlet ring basket 308, as depicted in FIG. 3-7, consists of a series of generally axially-oriented spindles 310 coupled to a forward ring 312 and extends forward from the inlet end 304 of the combustion liner 300. The forward ring 312 is positioned a distance from the combustion liner 300 in order to establish a mating location for a set of fuel nozzles (not shown) in order to position the fuel nozzles in the proper axial position within the combustor. The inlet ring basket 308 can be a fabricated component or a casting and is preferably made from a stainless steel material. Referring now to FIG. 10, the inlet ring basket 308 also includes a plurality of lugs 309 extending radially inward from the inlet ring basket 308 for use in securing a premixer assembly 330, as discussed in more detail below. The lugs 309 can be fabricated separately and welded to the inlet ring basket 308 or cast as part of the inlet ring basket 308.

Referring to FIGS. 4-7, the combustion liner 300 also comprises a premixer assembly 330. One component of the premixer 330 is one or more removable swirlers 332. Referring now to FIGS. 8-10, a swirler assembly 332 is depicted in the premixer assembly 330. The swirler assembly 332 comprises a premix tube 342 having an inlet end 342A and an opposing outlet end 342B, and a longitudinal axis C-C extending therethrough. The swirler assembly 332 also comprises a premix swirler 336 positioned within the premix tube 342 where the premix swirler 336 has a plurality of turning vanes 338 for imparting a swirl to a passing flow through the premix tube 342. For the embodiment depicted in FIGS. 8-10, the premix tube 342 is generally cylindrical. However, alternate shapes for the premix tube 342 are possible.

The swirler assembly 332 also comprises two mounting blocks for securing the swirler assembly in a gas turbine combustor. A first mounting block 344 is positioned along an outer wall of the premix tube 342 proximate the inlet end 342A of the premix tube 342. The first mounting block 344 has a first forward face 344A, an opposing first aft face 344B, a pair of generally parallel side faces 345, and an outer face 347. The outer face 347 can have an arc-like shape to it, at least along a portion of the outer face, in order for the mounting block 344 to conform to the shape of the inlet ring basket 308. The outer face 347 is used to set the radial position of the swirler assembly 332 and its contact with the inlet ring basket 308 to allow tighter dimensional control of the swirler assembly 332 relative to a fuel nozzle. The first mounting block 344 also includes a plurality of first holes 348 located in the arc-shaped outer face 347 and oriented generally perpendicular to the longitudinal axis C-C of the premix tube 342, as shown in FIG. 8.

The swirler assembly 332 also comprises a second mounting block 346 positioned along the outer wall of the premix tube 342 and spaced an axial distance from the first mounting block 344. The second mounting block 346 has a second forward face 346A and an opposing second aft face 346B, where the second aft face 346B is machined to a predetermined size in order to form a specific axial dimension for mounting the swirler assembly 332 in the proper axial location in the combustor. To position the swirler assembly 332 in the proper axial location, the second mounting block 346 includes a relief cut 360 machined into the second aft face 346B. The second mounting block 346 also has one or more second holes 356 extending through the second mounting block 346 in a direction generally perpendicular to the plurality of first holes 348.

For the embodiment of the present invention depicted in FIGS. 8-10, the second mounting block 346 is in direct axial alignment with the first mounting block 344. However, depending on the combustor geometry, the first and second mounting blocks 344 and 346 may not be in axial alignment, but clocked circumferentially relative to one another.

Each of the first mounting block 344 and second mounting block 346 are secured to the premix tube 342. Different methods of attachment for the mounting blocks are possible. In one embodiment, the first mounting block 344 and second mounting block 346 are welded to the premix tube 342. A bead of compatible weld material (compatible between the material of premix tube 342 and the mounting blocks 344 and 346) is laid down at the intersection of the mounting block and the premix tube 342.

An alternate method of securing the first and second mounting blocks 344 and 346 to the premix tube 342 is through a braze joint. A braze joint will help form a more complete joint as the entire surface of the mounting block in contact with the premix tube 342 is joined to the premix tube 342. In contrast, a weld joint only secures the mounting block to the premix tube 342 at the edges where the mounting block contacts the premix tube.

In yet another embodiment, it is possible for the mounting blocks 344 and 346 to be integral with the premix tube 342. The incorporation of the mounting blocks 344 and 346 into the premix tube 342 can be accomplished by a casting or forging.

The exact size, spacing and quantity of holes in the first mounting block 344 and the second mounting block 346 can vary and depends on a variety of factors such as combustor geometry, size of the swirler assemblies 332, and mechanical and thermal loading on the swirler assemblies 332. For an embodiment of the present invention depicted in FIGS. 8-10, the first mounting block 344 comprises two first holes 348 with the first holes 348 oriented generally perpendicular to the longitudinal axis C-C. The second mounting block 346 comprises one or more second holes 356, and the embodiment shown in FIGS. 8-10 utilizes a single second hole 356. However, it is possible that more than one second hole 356 is needed in order to secure the swirler assembly 342 to a combustor. For the embodiment shown in FIGS. 8-10, the second hole 356 is generally parallel to axis C-C.

As discussed above, the swirler assembly 332 is designed to be easily removable from a combustor to better facilitate maintenance and repair. Therefore, a plurality of removable fasteners 350 and 358 are utilized to secure the swirler assembly 332 in the combustor. In one embodiment, the removable fasteners, such as bolts, engage a corresponding thread pattern in the plurality of first holes 348 and one or more second holes 356. A thread pattern is but one way of securing the removable fasteners. Alternatively, the one or more second holes 356 could be through holes (i.e. not threaded) and utilize a nut adjacent to surface 346A. Furthermore, a bolt/stud could be welded/installed in lieu of hole 356 with a nut then placed on the surface of the dome plate 334.

The swirler assemblies 332 are positioned so as to be in fluid communication with adjacent tubes 352, also referred to as hoovers, which pass the flow of fuel and air from the swirler assembly 332 to the mixing zone of the combustion liner 300. That is, the swirler assemblies 332 are positioned so as to be adjacent to or slightly engaged in the tubes 352. In order to ensure that the swirler assemblies 332 are in the proper radial position in the combustion liner and form a radial clearance with the tubes 352, a plurality of stand offs 354 are located about the outer surface of each of the premix tubes 342, adjacent the outlet end 342B.

As discussed above, the swirler assemblies 332 are removably secured to the combustor through a plurality of fasteners 350 and 358, such as bolts or other means. For example, and as shown in FIGS. 6-10, the main swirler assemblies 332 are secured to the dome plate 334 by way of fasteners 350 and 358 passing through first holes 348 and second hole 356. Through the use of both radially and axially oriented fasteners 350 and 358, better positioning and tolerance control of the swirler assemblies 332 relative to the premixer assembly 330 and combustion liner 300 is achieved. Furthermore, through removably securing the swirler assemblies 332 to the premixer assembly 330, access for overhaul and repairs to the premixer assembly 330 is vastly improved compared to prior art combustors which had swirler assemblies welded to the premixer assembly. As one skilled in the art will appreciate, in addition to accessibility issues, welding of the swirler assemblies also causes deformation of the swirler assemblies, which can thereby affect flow control.

The swirler assemblies 332 are preferably manufactured from a material comparable to the premixer assembly 330, such as a type of stainless steel. The swirler assemblies 332 can also be a fabricated assembly of various machined parts or a casting.

Referring now to FIGS. 9 and 10, a swirler assembly 332 is shown installed within the premixer assembly 330. As discussed above, the swirler assembly 332 is secured in position by fasteners 350 and 358, which are oriented in both a radial and axial direction. The swirler assembly 332 is slid into position such that the standoffs 354 provide a radial clearance with respect to the tubes 352 and the second mounting block 346 contacts the lug 309 of the inlet ring basket 308 at the proper axial location due to the relief cut 360.

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 and required operations 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 swirler assembly for a gas turbine combustor comprising:

a premix tube having an inlet end, an opposing outlet end and a longitudinal axis extending therethrough;

a premix swirler positioned within the premix tube, the swirler having a plurality of turning vanes for imparting a swirl to a passing flow;

a first mounting block positioned along an outer wall of the premix tube proximate the inlet end and having a plurality of first holes oriented generally perpendicular to the longitudinal axis; and,

a second mounting block positioned along the outer wall of the premix tube a distance from the first mounting block, the second mounting block has one or more second holes extending through the second mounting block in a direction perpendicular to the plurality of first holes.

2. The swirler assembly of claim 1, wherein the premix tube is generally conical.

3. The swirler assembly of claim 1, wherein each of the first mounting block and second mounting block are secured to the premix tube.

4. The swirler assembly of claim 3, wherein the first and second mounting blocks are secured to the premix tube by a weld or braze joint.

5. The swirler assembly of claim 1, wherein the plurality of holes in the first mounting block comprise at least two holes.

6. The swirler assembly of claim 1, wherein the one or more second holes is threaded.

7. The swirler assembly of claim 1, wherein the second mounting block has a second forward face and opposing second aft face, where the second aft face is finish machined to a predetermined axial dimension.

8. A multi-point, multi-directional fastening assembly for use in a gas turbine combustor comprising:

a first mounting block secured to a body, the first mounting block having a first forward face, an opposing first aft face, a pair of side faces, an outer face, and a plurality of holes located in the outer face; and,

a second mounting block secured to the body, the second mounting block having one or more holes located therein;

wherein the second mounting block is spaced an axial distance from the first mounting block.

9. The fastening assembly of claim 8, wherein the outer face is arc-shaped at least at regions surrounding the plurality of holes.

10. The fastening assembly of claim 8, wherein the first mounting block is secured to the body by a weld or braze joint.

11. The fastening assembly of claim 8, wherein the second mounting block is secured to the body by a weld or braze joint.

12. The fastening assembly of claim 8, wherein the first and second mounting blocks are integral to the body.

13. The fastening assembly of claim 8, wherein the plurality of holes in the first mounting block are generally perpendicular to the one or more mounting holes in the second mounting block.

14. A removable swirler assembly in a combustor comprising:

a generally cylindrical body;

a center core positioned within the cylindrical body proximate an inlet of the generally cylindrical body;

a plurality of vanes extending between the center core and the generally cylindrical body;

a first mounting block secured to the generally cylindrical body, the first mounting block having a first forward face, an opposing aft face, a pair of side faces, and an outer face having a plurality of holes located therein; and,

a second mounting block secured to the generally cylindrical body, the second mounting block having one or more holes located therein;

wherein the removable swirler is fastened to the combustor at both the first mounting block and second mounting block through a plurality of removable fasteners.

15. The removable swirler of claim 14, wherein the plurality of vanes are oriented so as to impart swirl to a passing flow of air and fuel.

16. The removable swirler of claim 14, wherein the first mounting block extends in a circumferential distance greater than the second mounting block.

17. The removable swirler of claim 14, wherein the plurality of holes in the first mounting block are generally perpendicular to the single hole in the second mounting block.

18. The removable swirler of claim 14 further comprising a plurality of fasteners placed into the plurality of openings of the first mounting block for securing the swirler to the combustor.

19. The removable swirler of claim 14, wherein the outer face of the first mounting block is arc-shaped at least at regions proximate the plurality of holes.