System for providing fuel to a combustor

A system for providing fuel to a combustor of a gas turbine includes an annular fuel distribution manifold that at least partially defines a fuel plenum. The fuel distribution manifold includes a forward end axially separated from an aft end, a flange that extends radially outward and circumferentially around the forward end and an annular support ring that extends downstream from the flange. A LLI assembly extends downstream from the fuel distribution manifold. The LLI assembly includes a unibody liner that at least partially defines a primary combustion zone and a secondary combustion zone within the combustor. A LLI injector extends substantially radially through the unibody liner and provides for fluid communication through the unibody liner into the secondary combustion zone. A fluid conduit in fluid communication with the fuel plenum extends between the LLI injector and the fuel distribution manifold.

FIELD OF THE INVENTION

The present invention generally involves a combustor of a gas turbine. More specifically, the invention relates to a system for providing fuel to a secondary combustion zone defined within the combustor.

BACKGROUND OF THE INVENTION

A typical gas turbine that is used to generate electrical power includes an axial compressor at the front, one or more combustors downstream from the compressor, and a turbine at the rear. Ambient air may be supplied to the compressor, and rotating blades and stationary vanes in the compressor progressively impart kinetic energy to the working fluid (air) to produce a compressed working fluid at a highly energized state. The compressed working fluid exits the compressor and flows towards a head end of combustor where it reverses direction at an end cover and flows through the one or more nozzles into a primary combustion zone that is defined within a combustion chamber in each combustor. The compressed working fluid mixes with fuel in the one or more fuel nozzles and/or within the combustion chamber and ignites to generate combustion gases having a high temperature and pressure. The combustion gases expand in the turbine to produce work. For example, expansion of the combustion gases in the turbine may rotate a shaft connected to a generator to produce electricity.

A typical combustor includes an end cover coupled to a compressor discharge casing, an annular cap assembly that extends radially and axially within the compressor discharge casing, an annular combustion liner that extends downstream from the cap assembly, and a transition piece having an annular transition duct that extends between the combustion liner and a first stage of stationary nozzles. The stationary nozzles are positioned generally adjacent to an inlet to the turbine section.

In a particular combustor design, one or more LLI injectors, also known as late lean injectors, are circumferentially arranged around and mounted to the combustion liner downstream from the fuel nozzles and/or the primary combustion zone. Various fluid conduits and fluid couplings extend within the compressor discharge casing to route fuel from a fuel source to the LLI injectors. A portion of the compressed working fluid exiting the compressor is routed through the LLI injectors to mix with the fuel to produce a lean fuel-air mixture. The lean fuel-air mixture may then be injected into the combustion chamber for additional combustion in a secondary combustion zone to raise the combustion gas temperature and increase the thermodynamic efficiency of the combustor. The late lean injectors are effective at increasing combustion gas temperatures without producing a corresponding increase in the production of undesirable emissions such as oxides of nitrogen (NOX). The late lean injectors are particularly beneficial for reducing NOXduring base load and/or turndown operation of the gas turbine.

Installation and removal of a combustor having late lean injection hardware to and/or from a space limited environment such as the compressor discharge casing of the gas turbine has become increasingly challenging due in part to a decreasing footprint of many current gas turbine designs. For example, access to the various fluid couplings, fluid conduits and/or the LLI injectors may be restricted. In addition, valuable man hours required to assemble or disassemble the various late lean injection components to the combustor while mounted to the gas turbine may be excessive due to the difficulty related to proper installation and removal of the late lean injection hardware. Therefore, a system for providing fuel to the combustor that reduces assembly time and complexity of the combustor would be useful.

BRIEF DESCRIPTION OF THE INVENTION

One embodiment of the present invention is a system for providing fuel to a combustor of a gas turbine. The system includes an annular fuel distribution manifold that at least partially defines a fuel plenum. The fuel distribution manifold includes a forward end axially separated from an aft end, a flange that extends radially outward and circumferentially around the forward end and an annular support ring that extends downstream from the flange. A LLI injection assembly extends downstream from the fuel distribution manifold. The LLI injection assembly includes a unibody liner that at least partially defines a primary combustion zone and a secondary combustion zone within the combustor. A LLI injector extends substantially radially through the unibody liner and provides for fluid communication through the unibody liner into the secondary combustion zone. A fluid conduit in fluid communication with the fuel plenum extends between the LLI injector and the fuel distribution manifold.

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 at least one outer casing52such as a compressor discharge casing and/or an outer turbine casing. The outer casing52is in fluid communication with the compressor16and at least partially defines a high pressure plenum54that surrounds at least a portion of the combustor50. An end cover56is coupled to the outer casing52at one end of the combustor50. The combustor50generally includes at least one axially extending fuel nozzle58that extends downstream from the end cover56and an annular cap assembly60that extends radially and axially within the outer casing52downstream from the end cover56.

The outer casing generally includes at least one opening62for installing the combustor50. In one embodiment, an access or arm-way64extends through the outer casing52to provide for access to at least a portion of the combustor50from outside of the outer casing52. In one embodiment, the gas turbine10includes a stage of stationary turbine nozzles66that at least partially define an inlet68to the turbine28. The turbine28includes an inner casing70that circumferentially surrounds various stages of turbine rotor blades72that are coupled to the shaft30(FIG. 1) within the turbine28. In particular embodiments, the stationary turbine nozzles66are connected to the inner casing70. In further embodiments, the stationary nozzles66are also coupled to an inner support ring74.

In various embodiments, as shown inFIG. 2, the combustor50includes a system for providing fuel to a secondary combustion zone within the combustor50, herein referred to as “system100”.FIG. 3provides an assembled view of the system100according to particular embodiments, andFIG. 4provides an exploded view of the system100as shown inFIG. 3. As shown inFIG. 3, the system generally includes an upstream or forward end102and a downstream or aft end104. The forward end102is axially separated from the aft end104with respect to an axial centerline106of the system100. As shown inFIG. 3, the system100may be provided as a pre-assembled or at least partially pre-assembled combustion module108, thereby providing various benefits over exiting combustor configurations. For example, man hours related to on site assembly and disassembly may be significantly reduced. In addition or in the alternative, leak checks of critical fuel connections may be completed prior to installation of the system100, thereby improving overall safety and/or reliability of the combustor50.

In particular embodiments, as shown inFIG. 4, the combustion module100includes an annular fuel distribution manifold110that extends downstream from the forward end102towards the aft end206, a LLI injection assembly112that extends downstream from the fuel distribution manifold110and terminates at the aft end206, and at least one fluid conduit114that fluidly couples and/or connects the fuel distribution manifold110to the LLI injection assembly112. As shown inFIG. 2, the fuel distribution manifold110may at least partially surround a portion of the cap assembly60when installed into the combustor50.

In various embodiments, as shown inFIG. 3, the fluid conduit114provides for fluid communication between the fuel distribution manifold110and a LLI injector116such as a late-lean injector of the LLI injection assembly112. In one embodiment, the fluid conduit114is generally serpentine shaped. The serpentine shaped fluid conduit114allows for relative movement between the fuel distribution manifold110and the LLI injection assembly112as the outer casing52and or the combustor50transition through various thermal transient conditions such as during startup, shutdown and/or turndown operation of the gas turbine10. In addition, the serpentine shaped fluid conduit114may reduce load stress at a fuel connection port118(FIGS. 3 and 4) and/or at the LLI injector116, thereby improving the reliability of the system100and/or the overall performance of the combustor50.

In particular embodiments, as shown inFIG. 4, a flange120extends radially outward from and circumferentially around an upstream end122of the fuel distribution manifold110. A fuel distribution cap124extends outward from an outer surface126of the flange120. The outer surface126extends circumferentially around the flange120. An annular support sleeve or ring128extends downstream from the upstream end122of the flange120towards a downstream end130of the fuel distribution manifold110. The support ring128generally includes an inner surface132radially separated from an outer surface134. A compression spring seal136such as a hula seal may be disposed along the inner surface132.

In particular embodiments, as shown inFIG. 4, the fuel distribution cap124extends partially across the outer surface126of the flange120. For example, the fuel distribution cap124generally extends axially and circumferentially across at least a portion of the outer surface126of the flange120and radially outward from the outer surface126of the flange120. The fuel distribution cap124may be connected to the flange120by welding, brazing or by any other mechanical means known in the art suitable for the operating environment of the fuel distribution manifold110.

FIG. 5provides a cross sectional downstream view of the fuel distribution manifold110including the fuel distribution cap124according to one embodiment of the present invention, andFIG. 6provides an enlarged view of a portion of the fuel distribution manifold110including a portion of the fuel distribution cap124as shown inFIG. 5, according to at least one embodiment of the present disclosure. As shown inFIG. 5, a primary fuel plenum138extends circumferentially within the flange120. The primary fuel plenum138may be cast into the flange120and/or may be machined into the flange120. A plurality of bolt holes140extend axially through the flange120. The bolt holes140are generally evenly spaced circumferentially around the flange120to provide for an even pre-load around the circumference of the flange120when installed into the combustor50as shown inFIG. 2.

As shown inFIGS. 5 and 6, at least two orifices142extend through the outer surface126of the flange120to provide for fluid communication into the primary fuel plenum138. As shown inFIG. 5, each orifice142includes an inlet144generally adjacent to the outer surface126of the flange120and an outlet146that is generally adjacent and in fluid communication with the primary fuel plenum138. Each orifice142includes an inner surface148that extends between the inlet132and the outlet134. By having at least two of the orifices142, additional fuel inlet area may be provided when compared to a single orifice without offsetting the circumferential spacing between the bolt holes140. As a result fuel velocity may be lowered as fuel enters the primary fuel plenum138, thereby resulting in a more even fuel distribution within the primary fuel plenum138. In addition, by having at least two orifices142rather than one large orifice, wall thickness between each orifice142and a corresponding bolt hole140is optimized, thereby enhancing the durability of the flange120and allowing for a thinner flange120which decreases weight and cost. In addition, by having at least two orifices142, an even pre-load at each bolt hole140location around the flange120, thereby providing for an even/robust seal between the outer casing52(FIG. 2) and the flange120while maintaining a sufficient mass flow of the fuel20into the primary fuel plenum138.

In one embodiment, as shown inFIG. 6, the at least two orifices142comprises a first orifice152and a second orifice154extend radially through the outer surface126of the flange120to provide for fluid communication into the primary fuel plenum138. Both the first orifice152and the second orifice154orifice extend between two adjacent bolt holes140without interrupting a common circumferential spacing between each of the plurality of bolt holes140. In one embodiment, each of the first and the second orifices152,154includes an orifice insert156. Each orifice insert156is coaxially or concentrically aligned within each corresponding orifice152,154. The orifice inserts156may be sized and/or shaped the same or differently so as to achieve a desired flow rate of fuel flowing into the primary fuel plenum138.

In one embodiment, as shown inFIG. 6, each orifice insert156includes a rib158or other separation feature. The rib158generally positions the orifice insert156concentrically and/or coaxially into the corresponding orifice152,154. The rib158also provides for an insulation gap160between the orifice insert156and the corresponding orifice152,154, thereby reducing conductive cooling of the flange120caused by the fuel flowing through the corresponding orifice inserts152,154into the primary fuel plenum138. As a result, thermal stress associated with the thermal gradients between the fuel and the flange120may be reduced which enhances the overall durability of the fuel distribution manifold110.

In particular embodiments, as shown inFIGS. 5 and 6, the fuel distribution cap124extends or flares out across a portion of the outer surface126of the flange120to form a fuel distribution plenum162. The fuel distribution cap124generally extends across the inlet144of each of the orifices142and provides for fluid communication between the fuel distribution plenum162and the inlet144of each of the orifices142. By flaring the fuel distribution cap124, pressure head of the fuel20is at least partially stabilized before it is fed into each orifice142. As a result, the flow velocity of the fuel20may be regulated so as to evenly distribute the fuel20between each orifice142as the fuel flows into the primary fuel plenum138, thereby enhancing the overall performance of the fuel distribution manifold110. In particular embodiments, the fuel distribution cap124includes an inlet port164that provides for fluid communication between the fuel source22(FIG. 2) and the fuel distribution plenum162(FIGS. 5 and 6).

In one embodiment, as shown inFIG. 6, the fuel distribution cap124comprises a floor portion166that partially defines the fuel distribution plenum162. The floor portion defines at least one outlet167coaxially aligned with a corresponding orifice142and/or orifice insert156. An insulation gap168is defined between the floor portion166of the fuel distribution cap124and the outer surface126of the flange. In operation, the flange120is generally much hotter than the fuel20flowing into the fuel distribution cap124and into the orifices142. The insulation gap168provides an insulation boundary between the fuel20and the outer surface126of the flange120, thereby reducing thermal stresses around the fuel distribution cap124and along the flange120outer surface126. As a result, the overall durability of the fuel distribution manifold110may be enhanced.

Referring back toFIG. 4, the LLI injection assembly112generally includes a unibody liner200that extends between the fuel distribution manifold and the aft end206of the system100.FIG. 7provides a top view of the unibody liner as shown inFIG. 4according to various embodiments.FIG. 8provides a cross section side view of the unibody liner as shown inFIG. 7. As shown inFIGS. 7 and 8, the unibody liner200generally includes a main body202having a generally annular shape.

As shown inFIGS. 7 and 8, the main body202has a forward end204axially separated from an aft end206with respect to an axial centerline208of the unibody liner200. The main body202extends continuously from the forward end204to the aft end206, thereby eliminating the need for a separate combustion liner and transition duct as traditionally required in conventional combustion designs. In particular embodiments, the main body202comprises a conical portion210, a LLI injection portion212that extends downstream from the conical portion210and a transition portion214that extends downstream from the LLI injection portion212. In particular embodiments, the unibody liner200further includes a support portion216that extends upstream from the forward end204. The unibody liner200may be cast as a singular component or may be formed from individual components which are connected so as to form a continuous hot gas path through the combustor.

As shown inFIGS. 2 and 8, the unibody liner200generally defines a primary combustion zone218downstream from the forward end204and defined generally within the conical portion210, and a secondary combustion zone220that is disposed downstream from the primary combustion zone218and upstream from the aft end206. The secondary combustion zone220is defined at least partially within the LLI injection portion212.

The conical portion210extends between the forward end204and the LLI injection portion212, and the transition portion214extends downstream from the LLI injection portion212and terminates generally adjacent to the aft end206. The LLI injection portion212generally extends across at least a portion of the secondary combustion zone220. The conical portion210generally has a substantially circular cross section with respect to a plane that is perpendicular to the axial centerline208. The LLI injection portion212may have a substantially circular cross section and/or a substantially non-circular cross section with respect to a plane that is perpendicular to the axial centerline208. As shown inFIG. 7, the transition portion214has a substantially non-circular cross section with respect to a plane that is perpendicular to the axial centerline208.

In particular embodiments, as shown inFIGS. 7 and 8, one or more LLI injector openings222extend through the main body202downstream from the forward end204and upstream from the aft end206. The LLI injector openings222are disposed within the LLI injection portion212of the main body202. The LLI injector openings222provide for fluid communication through the main body202and into a hot gas path224that is at least partially defined within the main body202. In particular embodiments, as shown inFIG. 2, each of the LLI injector116extends at least partially through a corresponding one LLI injector opening222.

In at least one embodiment, as shown inFIG. 8, an axial flow length226is defined along the axial centerline208. The axial flow length226extends through the main body202between the forward end204and the aft end206. In particular embodiments, the LLI injection openings222generally define an intersection point228along the axial flow length226where the conical portion210and the LLI injection portion212intersect. The intersection point228may be defined adjacent to or upstream from the LLI injection openings222. Another intersection point230is generally defined along the axial flow length226where the LLI injection portion212and the transition portion214intersect. This intersection point230is generally defined at a position along the axial flow length226where the main body202transitions from a substantially circular cross section to a substantially non-circular cross section downstream from the LLI injector openings222.

The intersection points228and230are generally defined within a plane that is substantially perpendicular to the axial centerline208. The intersection points228and230may shift upstream or downstream from the shown positions shown inFIG. 8depending on such factors as the diameter of the unibody liner200, a desired or required mass flow rate through the unibody liner200, operating temperatures within the unibody liner200, thermal profile of the unibody liner200and/or positioning of the LLI openings222.

As shown inFIG. 8, the main body202defines a cross-sectional flow area232. The cross sectional flow area232is generally defined with respect to a plane that extends perpendicular to the axial centerline208. The cross-sectional flow area232may increase, decrease, or remain constant along any portion of the axial flow length226. The size of the cross-sectional flow area232of the body100main body202generally affects a flow velocity of the combustion gases26(FIG. 2) flowing through the main body202.

FIG. 9provides a normalized graphical illustration300of cross-sectional flow area232with respect to axial flow length226across the conical portion210, the LLI injection portion212and the transition portion214of the main body202of the unibody liner200. As illustrated by line304, the cross-sectional flow area232generally decreases along the axial flow length226from a maximum cross-sectional flow area232at the forward end204to a smaller cross-sectional flow area232at the intersection point228defined between the conical portion210and the LLI injection portion212of the main body202. It should be appreciated that line304also illustrates a cross-sectional area of a typical traditional liner (not shown).

In particular embodiments, as illustrated by line306, the cross-sectional flow area232may increase, remain constant and/or may decrease along the axial flow length226across the LLI injection portion212. In particular embodiments, as illustrated by lines308,310and312, the cross-sectional flow area232increases along at least a portion of the axial flow length226that is defined downstream from the intersection point230. In contrast, as illustrated by line314, the cross-sectional flow area232of the traditional liner continues to decrease through the LLI injection portion212and the transition portion214.

In one embodiment, as illustrated by line308, the cross-sectional flow area232increases continuously downstream from the intersection point230between the LLI injection portion212and the aft end206at a substantially continuous rate. In another embodiment, the cross-sectional flow area232increases continuously along a first portion316of the axial flow length226that is defined downstream from the intersection point230at a first rate of increase, and then increases at a second rate of increase along a second portion318of the axial flow length226that is defined downstream from the first portion316. In another embodiment, the cross-sectional flow area232increases continuously along the first portion316of the axial flow length226that is defined downstream from the intersection point230and then decreases along the second portion318of the axial flow length226that is defined downstream from the first portion316.

FIG. 10provides a normalized graphical illustration400of flow velocity402of the combustion gases26(FIG. 2) through the main body202of the unibody liner200including the traditional transition liner or duct with respect to axial flow length226through the conical portion210, the LLI injection portion212and the transition portion214of the main body202and traditional liner or duct. As shown betweenFIGS. 9 and 10, line404correlates to line304, line406correlates to line306, line408correlates to line308, line410correlates to line310, line412correlates to line312, line414correlates to line314,416correlates to316and418correlates to318.

As shown inFIGS. 9 and 10, and illustrated in lines304and404, the flow velocity of the combustion gases26(FIG. 2) increase as the cross-sectional flow area232decreases along the axial flow length226through the conical portion210. As illustrated by lines306,314and406and414, the flow velocity will increase at a much higher rate along the axial flow length226within the LLI injection portion212due to additional mass flow of the second combustible mixture and/or the compressed air through the main body202(FIG. 8) and into the hot gas path224(FIG. 8).

The increased flow velocity generally results in increased heat transfer coefficients at the transition portion214which results in hot spots or areas of high thermal stress on an inner surface (not shown) of the main body202of the unibody liner200and/or the traditional liner or duct. In the various embodiments of the present invention, as shown inFIG. 9by lines308,310,312, an increase in the cross-sectional flow area232at or downstream from the LLI injection portion212will result in a decrease in the flow velocity402of the combustion gases26(FIG. 2) as shown inFIG. 10by lines410,412and414. By maintaining or reducing the flow velocity402through the main body202of the unibody liner200at or downstream from the LLI injection portion212, heat transfer coefficients of the main body202are significantly reduced, thereby improving the durability and overall performance of the combustor.

Referring back toFIG. 4, in particular embodiments an aft frame250circumferentially surrounds the downstream end206of the unibody liner200. As shown inFIG. 2, the aft frame250may be coupled to the outer casing52to provide support for the aft end104of the system100. A mounting bracket251may be coupled to the aft frame250. The mounting bracket251may pivot in a forward direction and/or aft direction with respect to the axial centerline106(FIG. 3) of the system100. In this manner, the position or orientation of the mounting bracket251may be manipulated before and/or during installation of the system100to accommodate for tolerance stack up issues and/or to guide the system100and/or the LLI assembly112into position during installation into the combustor50.

As shown inFIG. 2the aft frame250is coupled to the outer casing52and the flange120is coupled to another portion of the outer casing52. This mounting scheme results in relative movement between the fuel distribution manifold110and the LLI assembly112as the combustor50and/or the gas turbine10transitions between various thermal transient conditions such as during startup, shutdown and/or turndown operation. As a result, the mounting bracket251may be allowed to pivot to accommodate for the relative movement between the fuel distribution manifold110and the LLI assembly112.

In particular embodiments, the aft frame250includes an inner portion252radially separated from an outer portion254and a pair of opposing sides256that extend between the inner and the outer portions252and254.FIG. 11provides an enlarged perspective view of one exemplary side portion258of the opposing side portions256of the aft frame250as shown inFIG. 4, according to at least one embodiment of the present disclosure.FIG. 12provides an enlarged backside view of the side portion258as shown inFIG. 11.

As shown inFIG. 11, the aft frame250includes a side seal slot260that extends along the side portion258. The side seal slot260extends at least partially between the inner portion252and the outer portion254of the aft frame250. Although the side seal slot260will be generally described with reference to one side portion256the for clarity, it should recognized by one of ordinary skill in the art that either or both of the opposing side portions256of the aft frame250may include a side seal slot260as described herein.

As shown inFIG. 11, the side seal slot260is at least partially defined between a downstream wall or aft wall262and an upstream wall or forward wall264of the aft frame250. The upstream wall264and the downstream wall262extend outward from and substantially perpendicular to an inner surface266of the side portion258. The upstream wall264and the downstream wall262extend at least partially between the inner portion252and the outer portion254of the aft frame250. In particular embodiments, the downstream wall262extends from the inner portion252to the outer portion254.

In one embodiment, as shown inFIG. 11, the upstream wall264comprises a first segment268and a second segment270. The first segment268extends along the first side portion258from the inner portion252towards the outer portion254of the aft frame250. The second segment270extends from an intersection point272with the first segment268towards the outer portion254of the aft frame250. The first segment268defines a first outer surface274, the second segment270defines a second outer surface276and the downstream wall262defines a third outer surface278.

In particular embodiments, as shown inFIG. 12, the first segment268of the upstream wall264extends outward from the inner surface266of the first side106of the aft frame250a first outward distance280. The first outward distance being defined between the inner surface266and the first outer surface274of the first segment268. The second segment270extends outward from the inner surface266a second outward distance282. The second outward distance282being defined between the inner surface266and the second outer surface274of the second segment270. The downstream wall262extends outward from the inner surface266of the aft frame250a third outward distance284. The third outward distance284being defined between the inner surface266and the third outer surface274of the downstream wall262. Each of the first outward distance280, the second outward distance282and the third outward distance284is measured with respect to a line that is substantially perpendicular to the inner surface266. In one embodiment, the third outward distance284is greater than the second outward distance282of the second segment270of the upstream wall.

In particular embodiments, as shown inFIG. 12, the first outward distance280of the first segment268is greater than the second outward distance282of the second segment270, thereby defining a step286at the intersection point272of the first segment268and the second segment270of the upstream wall264between the first outer surface274and the second outer surface276. As a result, the second segment270at least partially defines a key-way or side seal guide feature288, as shown inFIGS. 11 and 12, in the side portion258of the aft frame250.

FIGS. 13, 14 and 15illustrate one method for installing a side seal290into the side seal slot260utilizing the side seal guide feature288as illustrated inFIGS. 11 and 12and as described herein. In particular embodiments, as shown inFIGS. 11 and 12, the step286may be configured to guide a bottom portion292(FIG. 13) of the side seal290into the side seal slot260in a substantially axial and/or a radial direction with respect to the axial centerline208of the unibody liner200. For example, as shown inFIG. 12, the step286may be chamfered. In addition or in the alternative, the step286may be curved or rounded to guide the bottom portion292of the side seal290into the side seal slot260during installation of the system100into the combustor50.

As shown inFIG. 13, the side seal290may be inserted generally radially through the arm-way64. As shown inFIG. 14, the side seal290may be lowered such that a top portion294of the side seal290has generally cleared the outer casing52. The bottom portion292of the side seal290is generally aligned with the side seal guide feature288. The side seal290is then manipulated axially with respect to the axial centerline208into the side seal guide feature288towards the downstream wall262into the side seal slot260.FIG. 15provides a backside view of two adjacent aft frames250with the side seal290disposed between two adjacent side seal slots260as described herein. As shown inFIG. 15, the side seal290is then inserted radially into the side seal slot260. The side seal guide feature reduces radial clearance296needed between the outer casing52in order to install the side seal290without bending and/or twisting the side seal290. As a result, the potential for damaging the side seal290during installation may be greatly reduced, thereby increasing the mechanical life of the side seal290and/or reducing leakage of compressed working fluid between the high pressure plenum54and the hot gas path224.

Referring back toFIG. 4, in particular embodiments the LLI assembly further includes a flow sleeve500that circumferentially surrounds the unibody liner200.FIG. 16provides a cross sectional side view of the system100as shown inFIGS. 2, 3 and 4. As shown inFIGS. 4 and 16, the flow sleeve500includes a forward end502and an outer forward portion504disposed proximate to the forward end502, and an aft end506that is axially separated from the forward end502. The flow sleeve500extends continuously between the fuel distribution manifold110and the aft frame250and/or the aft end206of the main body202of the unibody liner200, thereby eliminating the need for an additional impingement sleeve. The forward portion504of the flow sleeve500may at least partially define an outer engagement surface508. In particular embodiments, as shown inFIGS. 4 and 16, the flow sleeve500extends continuously between the fuel distribution manifold110and the aft frame250. In particular embodiments, as shown inFIG. 5, the forward portion504of the flow sleeve500is positioned generally concentrically within the support ring128of the fuel distribution manifold110.

FIG. 17provides an enlarged view of a portion of the combustor50including a portion of the cap assembly60and a portion of the system100as shown inFIG. 2. In particular embodiments, as shown inFIG. 17, the outer engagement surface508of the forward portion504of the flow sleeve500is slidingly engaged with the inner surface132of the support ring128. In this manner, the flow sleeve500is allowed to slide or translate along the inner side132of the support ring128of the fuel distribution manifold110during operation of the combustor24. As further shown inFIG. 17, the support portion216of the main body202of the unibody liner200at least partially surrounds a portion of the cap assembly60.

In particular embodiments, as shown inFIG. 17, the compression or spring seal136extends radially between the outer engagement surface508of the forward portion504of the flow sleeve500and the inner side132of the support ring128. In particular embodiments, the spring seal136may be connected to the support ring128. In the alternative, the spring seal136may be connected to the flow sleeve500. The spring seal136at least partially provides structural support for the flow sleeve500during installation and/or operation of the gas turbine10while allowing for axial movement between the fuel distribution manifold110and the LLI assembly112during various operational modes of the gas turbine10such as during startup, shutdown and/or turndown operations.

In particular embodiments, as shown inFIG. 16, the flow sleeve500is radially separated from the unibody liner200so as to define an annular cooling flow passage510therebetween. The cooling flow passage510generally extends continuously along the length of the unibody liner200. For example, the cooling flow passage510extends continuously between the aft frame250and the forward end502of the flow sleeve500.

In particular embodiments, as shown inFIG. 4, the flow sleeve500may comprise a plurality of cooling or impingement holes512that provide for fluid communication through the flow sleeve500into the cooling flow passage510(FIG. 17) during operation of the gas turbine10. In at least one embodiment, as shown inFIG. 4, the flow sleeve500includes two semi-annular flow sleeve sections514that wrap at least partially around the unibody liner200. As shown inFIG. 3, the two semi-annular flow sleeve sections514may be joined together using a plurality of fasteners516such as bolts or other locking fasteners which are suitable for the operating environment of the system100within the combustor50. In the alternative, the semi-annular flow sleeve sections514may be welded or joined together by any mechanical means suitable for the operating environment within the combustor50.

In one embodiment, as shown inFIG. 16, the flow sleeve500is radially separated from the unibody liner200at a radial distance518that is generally constant between the aft frame250and the forward end204of the main body202of the unibody liner200. In another embodiment, the radial distance518between the unibody liner200and the flow sleeve500varies along/across the main body202of the unibody liner200. For example, the radial distance518may increase and/or decrease across the conical portion210, the LLI injection portion212and/or the transition portion214of the main body202of the unibody liner200to control a flow rate and/or velocity of the compressed working fluid18(FIG. 2) at a particular location on the main body202as it flows through the cooling flow passage510, thereby allowing for enhanced localized control over the cooling effectiveness of the compressed working fluid18in particular areas of the cooling flow passage510.

In particular embodiments, the flow sleeve500is separated from the main body202of the unibody liner200at a first radial distance520with respect to the conical portion210and a second radial distance522with respect to the transition portion214. In particular embodiments, the first radial distance520is greater than the second radial distance522along at least a portion of the conical portion210, thereby providing for effective impingement cooling at the transition portion214of the main body202of the unibody liner200while reducing a pressure drop of the compressed working fluid18as it flows from the high pressure plenum54(FIG. 2), through the cooling holes512(FIG. 4), into the cooling flow passage510(FIG. 16) and along the main body202. In the alternative, the second radial distance522may be greater than the first radial distance520along at least a portion of the transition portion214to control a flow velocity of the compressed working fluid18through the cooling flow passage510across the conical portion210.

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 passage510through the plurality of cooling holes512. The compressed working fluid18is focused onto the transition portion214of the main body202to provide impingement or jet cooling to the transition portion214. The radial distance518between the flow sleeve500and the conical portion210and/or the transition portion214is set at 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 passage510, thereby effectively cooling the main body202of the unibody liner200, particularly at hot spots formed by increased combustion temperatures caused that may result from late-lean injection. The continuously extending flow sleeve500eliminates traditional connection joints of current flow sleeve assemblies. As a result, leakage from the cooling flow passage510may be reduced or eliminated, thereby improving the overall efficiency of the combustor50. In addition, by eliminating the multiple components of existing flow sleeve assemblies, time and costs associated with assembly, disassembly and manufacture of the system100may be reduced.

As further shown inFIG. 17, the support portion216of the main body202of the unibody liner200may at least partially surround a portion of the cap assembly60and a compression or spring seal524may extend radially between the cap assembly60and the main body202. This allows for radial support of the unibody liner200while allowing for axial movement between the LLI assembly112and the fuel distribution manifold during operation of the gas turbine10.

Referring back toFIG. 4, in particular embodiments, the system100includes at least one outer air shield600that at least partially circumferentially surrounds at least a portion of the flow sleeve500. As shown inFIG. 3, the outer air shield(s)600surround the LLI injector116to form an injection air plenum604around the LLI injector116. In particular embodiments, as shown inFIGS. 3 and 4, the outer air shield(s)600are segmented into multiple outer air shields600.

FIG. 18provides a perspective view of the system100according to at least one alternate embodiment of the present invention, andFIG. 19provides a cross section side view of the system as shown inFIG. 18. As shown inFIGS. 18 and 19, the outer air shield600may comprise of two or more semi-annular outer air shield sections602that extend circumferentially around at least a portion of the flow sleeve500. As shown inFIG. 19the outer air shield600is radially separated from the flow sleeve500to define the injection air plenum604between the outer air shield600and the flow sleeve500. In particular embodiments, the outer air shield600at least partially surrounds each LLI injector116. The LLI injector116is in fluid communication with the injection air plenum604to allow for flow between the air injection plenum604and the hot gas path224(FIG. 2).

In particular embodiments, as shown inFIGS. 18 and 19, at least one inlet passage606extends through the outer air shield600to define a flow path608into the injection air plenum604. The inlet passage606generally provides for fluid communication between the high pressure plenum54(FIG. 2) and the injection air plenum604(FIG. 19). In this manner, the compressed working fluid18flows from the high pressure plenum54(FIG. 2), through the inlet passage606(FIGS. 18 and 19) along the flow path608(FIG. 19) into the air injection plenum604. The compressed working fluid18then flows through the injector116and into the hot gas path224. As shown inFIG. 18, the inlet passages606may be arranged in one or more rows610that extend circumferentially around at least a portion of the outer air shield600.

In various embodiments, as shown inFIGS. 18 and 19, the system includes an outer sleeve or flow regulation sleeve612. The flow regulation sleeve612extends circumferentially around at least a portion of the outer air shield600generally proximate to the inlet passages606. In one embodiment, the flow regulation sleeve612is positioned upstream from the inlet passages606with respect to a direction of flow of the compressed working fluid18flowing from the high pressure plenum54(FIG. 2) into the inlet passages606. In other words, the flow regulation sleeve612may be positioned over or on top of the inlet passages606. In particular embodiments, the flow regulation sleeve612is slidingly engaged with an outer surface614(FIG. 18) of the outer air shield600to provide for relative movement between the outer air shield600and the flow regulation sleeve612during operation of the combustor50. As shown inFIGS. 18 and 19, the flow regulation sleeve612may be coupled to a linkage mechanism616. The linkage mechanism616may be coupled to an actuating mechanism (not shown) such as a linear actuator to cause the flow regulation sleeve612to translate axially across and/or circumferentially around the outer air shield600.

FIG. 20illustrates a side view of a portion of the outer air shield600and the flow regulation sleeve612according to one embodiment of the present invention. As shown, the flow regulation sleeve612slides or translates in the axial direction618across the outer air shield600with respect to the axial centerline106of the system100. The flow regulation sleeve612generally slides or translates axially across the inlet passages606through various axial positions so as to at least partially open or at least partially close the inlet passages606, thereby increasing or restricting a flow rate of the compressed working fluid18flowing through the inlet passages606along the flow path608(FIG. 19) and into the injection air plenum604(FIG. 19). As a result, the flow of the compressed working fluid18(FIG. 19) flowing into the injection air plenum604during operation of the injector116may be adjusted, thereby providing for active control of the mass flow into the hot gas path224(FIG. 2) during late-lean injection, thus resulting in improved overall performance of the combustor50.

FIG. 21provides a perspective view of the system100including the flow regulation sleeve612according to an alternate embodiment of the present disclosure, andFIGS. 22 and 23illustrate the flow regulation sleeve612at various circumferential positions according to various embodiments of the present invention. As shown, the flow regulation sleeve612slides or translates circumferentially or in a circumferential direction620around the outer air shield600with respect to the axial centerline106of the system100. As shown inFIGS. 22 and 23, the flow regulation sleeve612generally slides or translates circumferentially across the inlet passages606through various positions so as to at least partially open or at least partially close the inlet passages606, thereby restricting or increasing flow of the compressed working fluid18(FIG. 2) flowing into the injection air plenum604along the flow paths90defined by the inlet passages606.

In particular embodiments, as shown inFIGS. 22 and 23the flow regulation sleeve612includes a plurality of openings622. The openings622are generally arranged to at least partially align with the inlet passages606as the flow regulation sleeve612slides or translates through the various circumferential positions. The flow regulation sleeve612may be positioned at any point between a first position624(FIG. 22) wherein flow of the compressed working fluid18through the inlet passages606(FIG. 19) along the flow paths608(FIG. 19) is fully restricted, and a second position626(FIG. 23) where flow of the compressed working fluid18(FIG. 2) through the inlet passages606(FIG. 19) along the flow paths608(FIG. 19) is fully open or unrestricted by the flow regulation sleeve612, thereby increasing the flow through the inlet passages606along the flow paths608and into the injection air plenum604.

During certain operation modes of the gas turbine10such as during cold fuel operation, liquid fuel operation and/or start-up operation the flow regulation sleeve612may be actuated so that is slides or translates across and/or around the outer air shield600to at least partially or fully restrict the flow of the compressed working fluid18through the inlet passages606, thereby reducing or preventing air dilution to the combustion gases26(FIG. 2) flowing through the hot gas path224.

The flow regulation sleeve612provides a flow barrier between the high pressure plenum54(FIG. 2) and the injection air plenum604(FIG. 19). As a result, a greater portion of the compressed working fluid18may be routed through the cooling flow passage510and through the fuel nozzle58(FIG. 2), thereby reducing the potential for flame holding at the fuel nozzle58. In addition, by shutting off or restricting the flow of the compressed working fluid18to the injection air plenum604, dilution of the combustion gases26flowing through the hot gas path224may be reduced or eliminated, thereby enhancing emissions performance and/or mechanical performance of the combustor50.