Flow sleeve for a combustion module of a gas turbine

A combustion module for a combustor of a gas turbine includes an annular fuel distribution manifold disposed at an upstream end of the combustion module. The fuel distribution manifold includes an annular support sleeve having an inner surface. The combustion module further includes a fuel injection assembly having an annular combustion liner that extends downstream from the fuel distribution manifold and that terminates at an aft frame, and an annular flow sleeve that circumferentially surrounds the combustion liner. The flow sleeve extends downstream from the fuel distribution manifold and terminates at the aft frame. The flow sleeve extends continuously between the support sleeve and the aft frame. A forward portion of the flow sleeve is positioned concentrically within the support sleeve where the forward portion is slidingly engaged with the inner surface of the support sleeve.

FIELD OF THE INVENTION

The present invention generally involves a combustor for a gas turbine. More specifically, the invention relates to a flow sleeve for a combustion module of the combustor.

BACKGROUND OF THE INVENTION

A combustion section of a gas turbine generally includes a plurality of combustors that are arranged in an annular array around an outer casing such as a compressor discharge casing. Pressurized air flows from a compressor to the compressor discharge casing and is routed to each combustor. Fuel from a fuel nozzle is mixed with the pressurized air in each combustor to form a combustible mixture within a primary combustion zone of the combustor. The combustible mixture is burned to produce hot combustion gases having a high pressure and high velocity.

In a typical combustor, the combustion gases are routed towards an inlet of a turbine of the gas turbine through a hot gas path that is at least partially defined by an annular combustion liner and an annular transition duct that extends downstream from the combustion liner and terminates at the inlet to the turbine. Thermal and kinetic energy are transferred from the combustion gases to the turbine to cause the turbine to rotate, thereby producing mechanical work. For example, the turbine may be coupled to a shaft that drives a generator to produce electricity.

In particular combustors, a combustion module is utilized to inject a generally lean fuel-air mixture into the hot gas path downstream from the primary combustion zone. The combustion module generally includes an annular fuel distribution manifold that circumferentially surrounds a portion of a cap assembly that partially surrounds the fuel nozzle, and a fuel injection assembly that extends between the fuel distribution manifold and the inlet to the gas turbine. The fuel injection assembly includes an annular combustion liner that extends continuously between the cap assembly and the inlet to the turbine. The continuously extending combustion liner defines the hot gas path within the combustor, thereby eliminating the separate transition duct. The combustion liner includes an annular main body that comprises of a conical section having a substantially circular cross section and a transition section that extends downstream from the conical section and that has a substantially non-circular cross section. The fuel injection assembly further includes a plurality of radially extending fuel injectors, also known as late lean fuel injectors that inject the lean fuel-air combustible mixture into the hot gas path downstream from the primary combustion zone. As a result, the combustion gas temperature is increased and the thermodynamic efficiency of the combustor is improved without producing a corresponding increase in the production of undesirable emissions such as oxides of nitrogen (NOX). However, the increase in the temperature of the combustion gases results in an increase of thermal stresses on the combustion liner.

One technique for cooling the combustion liner of the combustion module includes surrounding the combustion liner with a flow sleeve assembly so as to define a cooling flow passage therebetween, and routing a portion of the compressed working fluid through the cooling passage to provide at least one of impingement, convective or conductive cooling to the combustion liner. The flow sleeve assembly generally includes an annular support sleeve that surrounds a forward end portion of the combustion liner and that is positioned concentrically within the fuel distribution manifold, an annular flow sleeve that is coupled to an aft end of the support sleeve and that surrounds the conical section of the combustion liner, and an annular impingement sleeve that is coupled to an aft end of the flow sleeve and that surrounds the transition section of the combustion liner.

While the flow sleeve assembly is generally effective for cooling the combustion liner, the multiple connections between the various components may leak or develop leaks over time due to tolerance issues and/or due to thermal and/or mechanical cycle fatigue, thereby impacting the overall cooling effectiveness and durability of the flow sleeve assembly. In addition, the loss of the compressed working fluid from the cooling passage may result in a decrease of combustor performance due to a decrease in the amount of the compressed working fluid that is routed to the fuel nozzle for combustion. Furthermore, the multiple components increase time and costs associated with assembly, disassembly and the manufacture of the combustion module. Therefore, an improved system for cooling the combustion liner of the combustion module would be useful.

BRIEF DESCRIPTION OF THE INVENTION

One embodiment of the present invention is a combustion module for a combustor of a gas turbine that includes an annular fuel distribution manifold disposed at an upstream end of the combustion module. The fuel distribution manifold includes an annular support sleeve having an inner surface. The combustion module further includes a fuel injection assembly having an annular combustion liner that extends downstream from the fuel distribution manifold and that terminates at an aft frame, and an annular flow sleeve that circumferentially surrounds the combustion liner. The flow sleeve extends downstream from the fuel distribution manifold and terminates at the aft frame. The flow sleeve extends continuously between the support sleeve and the aft frame. A forward portion of the flow sleeve is positioned concentrically within the support sleeve where the forward portion is slidingly engaged with the inner surface of the support sleeve.

Another embodiment of the present invention is a combustor. The combustor includes an end cover that is coupled to an outer casing that surrounds the combustor, an axially extending fuel nozzle that extends downstream from the end cover, an annular cap assembly that extends radially and axially within the combustor where the cap assembly at least partially surrounds the fuel nozzle, and a combustion module having an annular fuel distribution manifold that circumferentially surrounds at least a portion of the cap assembly. The combustion module further includes a fuel injection assembly that extends downstream from the fuel distribution manifold. The fuel injection assembly includes an annular combustion liner that extends downstream from the cap assembly and that terminates at an aft frame, and an annular flow sleeve that surrounds the combustion liner. The flow sleeve includes a forward portion that is positioned concentrically within the fuel distribution manifold, and an aft end that is coupled to the aft frame. The flow sleeve extends continuously between the forward portion of the flow sleeve and the aft frame.

The present invention may also include a gas turbine. The gas turbine generally includes a compressor, a compressor discharge casing disposed downstream from the compressor and a turbine disposed downstream from the compressor discharge casing. A combustor extends at least partially through the compressor discharge casing. The combustor includes an end cover that is coupled to the compressor discharge casing, an axially extending fuel nozzle that extends downstream from the end cover, an annular cap assembly that is disposed downstream from the end cover and that at least partially surrounds the fuel nozzle, and a combustion module that extends downstream from the cap assembly. The combustion module includes an annular fuel distribution manifold that circumferentially surrounds at least a portion of the cap assembly. The fuel distribution manifold includes a radially extending mounting flange that is coupled to the compressor discharge casing and an axially extending annular support sleeve that includes an inner surface. The combustion module further includes a fuel injection assembly that extends downstream from the fuel distribution manifold. The fuel injection assembly includes an annular combustion liner that extends downstream from the cap assembly and terminates at an aft frame. An annular flow sleeve surrounds the combustion liner and a plurality of fuel injectors extend through the flow sleeve and the combustion liner downstream from the cap assembly. The fuel injectors are fluidly connected to the fuel distribution manifold. The flow sleeve includes a forward portion that is positioned concentrically within the support sleeve between the combustion liner and the inner surface of the support sleeve and an aft end that is coupled to the aft frame. The flow sleeve extends continuously between the forward portion of the flow sleeve and the aft frame.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention. As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows. The term “radially” refers to the relative direction that is substantially perpendicular to an axial centerline of a particular component, and the term “axially” refers to the relative direction that is substantially parallel to an axial centerline of a particular component.

Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. Although exemplary embodiments of the present invention will be described generally in the context of a combustor incorporated into a gas turbine for purposes of illustration, one of ordinary skill in the art will readily appreciate that embodiments of the present invention may be applied to any combustor incorporated into any turbomachine and is not limited to a gas turbine combustor unless specifically recited in the claims.

Referring now to the drawings, wherein identical numerals indicate the same elements throughout the figures,FIG. 1provides a functional block diagram of an exemplary gas turbine10that may incorporate various embodiments of the present invention. As shown, the gas turbine10generally includes an inlet section12that may include a series of filters, cooling coils, moisture separators, and/or other devices to purify and otherwise condition a working fluid (e.g., air)14entering the gas turbine10. The working fluid14flows to a compressor section where a compressor16progressively imparts kinetic energy to the working fluid14to produce a compressed working fluid18at a highly energized state.

The compressed working fluid18is mixed with a fuel20from a fuel supply22to form a combustible mixture within one or more combustors24. The combustible mixture is burned to produce combustion gases26having a high temperature and pressure. The combustion gases26flow through a turbine28of a turbine section to produce work. For example, the turbine28may be connected to a shaft30so that rotation of the turbine28drives the compressor16to produce the compressed working fluid18. Alternately or in addition, the shaft30may connect the turbine28to a generator32for producing electricity. Exhaust gases34from the turbine28flow through an exhaust section36that connects the turbine28to an exhaust stack38downstream from the turbine28. The exhaust section36may include, for example, a heat recovery steam generator (not shown) for cleaning and extracting additional heat from the exhaust gases34prior to release to the environment.

FIG. 2provides a cross sectional side view of a portion of an exemplary gas turbine10including an exemplary combustor50that may encompass various embodiments of the present disclosure. As shown, the combustor50is at least partially surrounded by an outer casing52such as a compressor discharge casing54that is disposed downstream from the compressor and/or an outer turbine casing56. The outer casing52is in fluid communication with the compressor16and at least partially defines a high pressure plenum58that surrounds at least a portion of the combustor50. An end cover60is coupled to the outer casing52at one end of the combustor50.

As shown inFIG. 2, the combustor50generally includes at least one axially extending fuel nozzle62that extends downstream from the end cover60, an annular cap assembly64that extends radially and axially within the outer casing52downstream from the end cover60, an annular hot gas path duct or combustion liner66that extends downstream from the cap assembly64and an annular flow sleeve68that surrounds at least a portion of the combustion liner66. The combustion liner66defines a hot gas path70for routing the combustion gases26through the combustor50. The end cover60and the cap assembly64at least partially define a head end72of the combustor50.

The cap assembly64generally includes a forward end74that is position downstream from the end cover60, an aft end76that is disposed downstream from the forward end74, and one or more annular shrouds78that extend at least partially therebetween. In particular embodiments, the axially extending fuel nozzle(s)62extend at least partially through the cap assembly64to provide a first combustible mixture80that consists primarily of the fuel20(FIG. 1) and a portion of the compressed working fluid18from the compressor16to a primary combustion zone82that is defined within the combustion liner66downstream from the aft end76of the cap assembly64.

In particular embodiments, the combustor50further includes one or more radially extending fuel injectors84also known as late-lean fuel injectors that extend through the flow sleeve68and the combustion liner66at a point that is downstream from the at least one axially extending fuel nozzle62. The combustion liner66defines a combustion chamber86within the combustor50. In particular embodiments, the combustion liner66further defines a secondary combustion zone88that is proximate to the fuel injector(s)84and downstream from the primary combustion zone82. In particular embodiments, the combustion liner66, the flow sleeve68and the fuel injector(s)84are provided as part of a combustion module100that extends through the outer casing52and that circumferentially surrounds at least a portion of the cap assembly64.

FIG. 3provides a perspective view of the combustion module100as shown inFIG. 2, andFIG. 4provides an exploded perspective view of the combustion module100as shown inFIG. 3. As shown inFIG. 3, the combustion module100is generally provided as an assembled or singular component. The combustion module100includes a forward or upstream end102that is axially separated from an aft or downstream end104with respect to an axial centerline106of the combustion module100.

In particular embodiments, as shown inFIG. 4, the combustion module100includes an annular fuel distribution manifold108disposed at the upstream end102of the combustion module100and a fuel injection assembly110that extends downstream from the fuel distribution manifold108and that terminates at the downstream end104of the combustion module100. The fuel distribution manifold108includes a radially extending mounting flange112that extends circumferentially around a forward end114of the fuel distribution manifold108. As shown inFIG. 2, the mounting flange112at least partially defines a fuel plenum116. As shown inFIGS. 2 and 4, a fuel inlet port118extends outward from the mounting flange112. The fuel inlet port118provides for fluid communication between the fuel supply22(FIG. 1) and the fuel plenum116(FIG. 2). As shown inFIG. 4, the fuel distribution manifold108further includes an annular support sleeve120having an inner side122that is radially separated from an outer side124. The annular support sleeve120extends generally axially downstream from the mounting flange112.

In particular embodiments, as shown inFIG. 4, the combustion liner66, the flow sleeve68and the fuel injector(s)84are included as part of the fuel injection assembly110. As shown inFIG. 3, each fuel injector84may be fluidly coupled to the fuel distribution manifold108through a fluid conduit126that extends between the fuel injector84and the mounting flange112.

FIG. 5provides a cross sectional side view of the combustion module100as shown inFIGS. 2, 3 and 4, andFIG. 6provides a side view of the combustion liner66of the combustion module100. As shown inFIG. 5, the combustion liner66extends downstream from the fuel distribution manifold108and an aft or downstream end128of the combustion liner66terminates at an aft frame130or other support structure that circumferentially surrounds the aft end128as shown inFIG. 3. As shown inFIG. 3, a mounting bracket131may be coupled to the aft frame130. In one embodiment, as shown inFIG. 2, the aft frame130and/or the mounting bracket131is coupled to the outer turbine casing56and the mounting flange112of the fuel distribution manifold108is connected to the compressor discharge casing54so as to constrain the combustion module100at both the forward and aft ends102,104of the combustion module100.

As shown inFIG. 6, the combustion liner66comprises an annular main body132. The main body132generally includes a forward end134axially separated from an aft end136with respect to an axial centerline138of the combustion liner66. The main body132extends continuously from the forward end134to the aft end136. The main body132includes an outer or cold side140that extends between the forward end134and the aft end136. In particular embodiments, as shown inFIGS. 3 and 6, a plurality of cooling features142such as raised ribs or turbulators extend radially outward from the outer surface140of the main body132.

In particular embodiments, as shown inFIG. 6, the main body132comprises a conical section144and a transition section146, thereby eliminating the need for a separate transition duct. A transitional intersection148is defined between the forward end134and the aft end136of the main body132at a point where the conical section144and the transition section146intersect. For example, where the main body132begins to change from a generally circular cross section to a non-circular cross section. In particular embodiments, an annular flange150is disposed at the forward end132of the main body132. The flange150at least partially surrounds a portion of the cap assembly64(FIG. 2). In particular embodiments, as shown in FIG.6, the cooling features142may be disposed on the conical section144and/or the transition section146of the main body132.

As shown inFIGS. 4 and 5, the flow sleeve68includes a forward end152and an outer forward portion154disposed proximate to the forward end152and an aft end156that is axially separated from the forward end152with respect to the axial centerline106(FIG. 5) of the combustion module100. The forward portion154of the flow sleeve68may at least partially define an outer engagement surface158. In particular embodiments, as shown inFIG. 5, the flow sleeve68extends continuously between the fuel distribution manifold108and the aft frame130. In particular embodiments, as shown inFIG. 5, the forward portion154of the flow sleeve68is positioned generally concentrically within the support sleeve120of the fuel distribution manifold108.

FIG. 7provides an enlarged view of a portion of the combustor50including a portion of the cap assembly64and a portion of the combustion module100as shown inFIG. 2. In particular embodiments, as shown inFIG. 7, the outer engagement surface158of the forward portion154of the flow sleeve68is slidingly engaged with the inner surface122of the support sleeve120. In this manner, the flow sleeve68is allowed to slide or translate along the inner side122of the support sleeve120of the fuel distribution manifold108during operation of the combustor24. As further shown inFIG. 7, the flange150of the main body132of the combustion liner66at least partially surrounds a portion of the cap assembly64.

In particular embodiments, as shown inFIG. 7, a compression or spring seal162such as a hula seal extends radially between the outer engagement surface158of the forward portion154of the flow sleeve68and the inner side122of the support sleeve120. In particular embodiments, the spring seal162may be connected to the support sleeve120. In the alternative, the spring seal162may be connected to the flow sleeve68. The spring seal162at least partially provides structural support for the flow sleeve68during installation and/or operation of the gas turbine10while allowing for axial movement between the fuel distribution manifold108and the fuel injection assembly110during various operational modes of the gas turbine10such as during startup, shutdown and/or turndown operations.

In particular embodiments, as shown inFIG. 5, the flow sleeve68is radially separated from the combustion liner66so as to define an annular cooling flow passage164therebetween. The cooling flow passage164generally extends continuously along the length of the combustion liner66. For example, the cooling flow passage164extends continuously between the aft frame130and the forward portion154and/or the forward end152of the flow sleeve68.

In particular embodiments, as shown inFIG. 4, the flow sleeve68may comprise a plurality of cooling or impingement holes166that provide for fluid communication through the flow sleeve68into the cooling flow passage164(FIG. 5) during operation of the gas turbine10. In at least one embodiment, as shown inFIGS. 3 and 4, the flow sleeve68includes two semi-annular flow sleeve sections168that wrap at least partially around the combustion liner66(FIG. 5). As shown inFIG. 3, the two semi-annular flow sleeve sections168are joined together using a plurality of fasteners170such as bolts or other locking fasteners which are suitable for the operating environment of the combustion module100. In the alternative, the semi-annular flow sleeve sections168may be welded or joined together by any mechanical means suitable for the operating environment within the combustor50.

In one embodiment, as shown inFIG. 5, the flow sleeve68is radially separated from the combustion liner66at a radial distance172that is generally constant between the aft frame and the forward end152of the main body132of the combustion liner66. In another embodiment, the radial distance172between the combustion liner66and the flow sleeve68varies along/across the cold side140of the main body132of the combustion liner66. For example, the radial distance172may increase and/or decrease across the conical section144and/or the transition section146of the combustion liner66to control a flow rate and/or velocity of the compressed working fluid18(FIG. 2) at a particular location on the main body132as it flows through the cooling flow passage164, thereby allowing for enhanced localized control over the cooling effectiveness of the compressed working fluid18in particular areas of the cooling flow passage164.

In particular embodiments, the flow sleeve68is separated from the combustion liner64at a first radial distance174with respect to the conical section144and a second radial distance176with respect to the transition section146. In particular embodiments, the first radial distance174is greater than the second radial distance176along at least a portion of the conical section144of the combustion liner66, thereby providing for effective impingement cooling at the transition section146of the main body132of the combustion liner66while reducing a pressure drop of the compressed working fluid as it flows from the high pressure plenum58, through the cooling holes166, into the cooling flow passage164and onto the cold side140of the main body132. In the alternative, the second radial distance176may be greater than the first radial distance168along at least a portion of the transition section146of the combustion liner66to control a flow velocity of the compressed working fluid18through the cooling flow passage164across the conical section144of the main body132of the combustion liner66.

In operation, as described above and as illustrated in the various figures, a portion of the compressed working fluid18from the compressor16is routed into the cooling flow passage164through the plurality of cooling or impingement holes166. The compressed working fluid18is focused onto the outer or cold side140of the combustion liner66at the transition section146to provide impingement or jet cooling to the transition section146of the main body132of the combustion liner66. The radial distance172between the flow sleeve68and the conical section144and/or the transition section146of the combustion liner66is set as a constant distance and/or a varying radial distance to control the flow volume and/or velocities of the compressed working fluid18through the cooling flow passage164, thereby effectively cooling the combustion liner, particularly at hot spots formed by increased combustion temperatures caused by late-lean fuel injection.

The compressed working fluid18provides at least one of impingement, convective or conductive cooling to the combustion liner66as it is routed through the cooling flow passage164and on towards the head end58of the combustor50. The continuously extending flow sleeve68eliminates any of the connection joints of previous flow sleeve assemblies. As a result, leakage from the cooling flow passage is eliminated, thereby improving the overall efficiency of the combustor50. In addition, by eliminating the multiple components of existing flow sleeve assemblies, the time and costs associated with assembly, disassembly and manufacture of the combustion module100are decreased.