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.
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.
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.
The present invention is described in detail below with reference to the attached drawing figures, wherein:
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
The present invention is shown in detail in
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
Referring to
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
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
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
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
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
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.
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.
Number | Date | Country | |
---|---|---|---|
61815835 | Apr 2013 | US |