US20130152594A1 - Gas turbine and fuel injector for the same - Google Patents
Gas turbine and fuel injector for the same Download PDFInfo
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- US20130152594A1 US20130152594A1 US13/327,131 US201113327131A US2013152594A1 US 20130152594 A1 US20130152594 A1 US 20130152594A1 US 201113327131 A US201113327131 A US 201113327131A US 2013152594 A1 US2013152594 A1 US 2013152594A1
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- fuel
- central cavity
- combustor
- fuel injector
- air
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23R—GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS
- F23R3/00—Continuous combustion chambers using liquid or gaseous fuel
- F23R3/28—Continuous combustion chambers using liquid or gaseous fuel characterised by the fuel supply
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23R—GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS
- F23R3/00—Continuous combustion chambers using liquid or gaseous fuel
- F23R3/28—Continuous combustion chambers using liquid or gaseous fuel characterised by the fuel supply
- F23R3/36—Supply of different fuels
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Abstract
A fuel injector for a gas turbine engine includes an injector housing having a central cavity configured to fluidly couple with a combustor of the gas turbine engine. The fuel injector may include a fuel nozzle at the upstream end of the central cavity. The fuel nozzle may be configured to direct a first fuel into the central cavity. The fuel injector may also include an annular air inlet disposed circumferentially about the fuel nozzle at the upstream end of the central cavity, and an annular air discharge outlet circumferentially disposed about the exit opening of the central cavity. The fuel injector may further include an annular fuel discharge outlet circumferentially disposed about the air discharge outlet. The fuel discharge outlet may be configured to discharge a second fuel into the combustor circumferentially around the air discharge outlet.
Description
- The present disclosure relates generally to a fuel injector for a gas turbine engine.
- In a typical gas turbine engine (GTE), one or more fuel injectors direct a liquid or gaseous hydrocarbon fuel into a combustion chamber (called combustor) for combustion. The combustion of hydrocarbon fuels in the combustor produce undesirable exhaust constituents such as NOx. Different techniques are used to reduce the amount of NOx emitted by GTEs. In one technique, a lean premixed fuel-air mixture is directed to the combustor to burn at a relatively low combustion temperature. A low combustion temperature reduces NOx formation. In another technique, steam is directed to the combustor to reduce the temperature and reduce NOx production. U.S. Pat. No. 7,536,862 B2 to Held et al. (the '862 patent) describes a fuel injector for a gas turbine engine in which fuel is injected from the fuel injector into the combustor through primary and secondary openings. Steam is injected alongside the fuel to decrease the temperature of the flame in the combustor, and thereby reduce NOx production.
- In one aspect, a fuel injector for a gas turbine engine is disclosed. The fuel injector includes an injector housing including a central cavity extending along a longitudinal axis from an upstream end to a downstream end. The downstream end of the central cavity may include an exit opening configured to fluidly couple the central cavity to a combustor of the gas turbine engine. The fuel injector may include a fuel nozzle at the upstream end of the central cavity. The fuel nozzle may be configured to direct a first fuel into the central cavity. The fuel injector may also include an annular air inlet of the central cavity disposed circumferentially about the fuel nozzle at the upstream end of the central cavity, and an annular air discharge outlet circumferentially disposed about the exit opening of the central cavity. The fuel injector may further include an annular fuel discharge outlet circumferentially disposed about the air discharge outlet. The fuel discharge outlet may be configured to discharge a second fuel into the combustor circumferentially around the air discharge outlet.
- In another aspect, a method of operating a gas turbine engine is disclosed. The method may include directing a premixed fuel-air mixture into a combustor of the gas turbine engine through a central cavity of a fuel injector. The premixed fuel-air mixture may be a mixture of a first fuel and a first quantity of compressed air. The central cavity may extend from a first end fluidly coupled to the combustor to a second end. The method may also include directing a second quantity of compressed air into the combustor circumferentially around the premixed fuel-air mixture. The method may further include increasing an angular velocity of a second fuel in the fuel injector, and directing the second fuel into the combustor circumferentially around the second quantity of compressed air.
- In yet another aspect, a gas turbine engine is disclosed. The gas turbine engine may include a combustor system including a combustor, and a fuel injector extending from a first end to a second end. The fuel injector may be coupled to the combustor at the first end and may include a central cavity extending from the first end to the second end along a longitudinal axis. The central cavity may be configured to direct a premixed fuel-air mixture into the combustor. The fuel injector may include a fuel nozzle centrally located on the central cavity at the second end and may be configured to direct a gaseous fuel into the central cavity. The fuel injector may also include a first air discharge outlet circumferentially disposed around the fuel nozzle. The first air discharge outlet may be configured to direct a first quantity of compressed air into the central cavity to mix with the gaseous fuel and create the premixed fuel-air mixture in the central cavity. The fuel injector may also include a second air discharge outlet configured to direct a second quantity of compressed air into the combustor circumferentially around the premixed fuel-air mixture entering the combustor from the central cavity. The fuel injector may further include an outer passageway circumferentially disposed about the central cavity. The outer passageway may be configured to selectively direct a gaseous fuel and/or a liquid fuel into the combustor circumferentially around the second quantity of compressed air when operated in a co-firing mode or singly when operated in a more conventional mode.
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FIG. 1 is an illustration of an exemplary disclosed gas turbine engine system; -
FIG. 2 is a perspective view of an exemplary fuel injector used in the turbine engine ofFIG. 1 ; -
FIG. 3 is a cross-sectional illustration of the fuel injector ofFIG. 2 ; and -
FIG. 4 is a flow chart that illustrates an exemplary operation of the fuel injector ofFIG. 2 . -
FIG. 1 illustrates an exemplary gas turbine engine (GTE) 100. GTE 100 may have, among other systems, acompressor system 10, acombustor system 20, aturbine system 70, and anexhaust system 90 arranged along anengine axis 98.Compressor system 10 compresses air and delivers the compressed air to anenclosure 72 ofcombustor system 20. The compressed air is then directed fromenclosure 72 into acombustor 50 through one ormore fuel injectors 30 positioned therein. One or more types of fuel (such as, for example, a gaseous fuel and a liquid fuel) may be directed to thefuel injector 30 through fuel lines (not identified). GTE 100 may operate using different types of fuel depending upon availability of a particular fuel. For instance, when GTE 100 operates at a site with an abundant supply of a gaseous fuel (such as natural gas), the gaseous fuel may be used to operate the GTE 100. Under some operating conditions, another type of fuel (such as diesel fuel) may be used to operate the GTE 100. The fuel burns incombustor 50 to produce combustion gases at high pressure and temperature. These combustion gases are used in theturbine system 70 to produce mechanical power.Turbine system 70 extracts energy from these combustion gases, and directs the exhaust gases to the atmosphere throughexhaust system 90. The layout of GTE 100 illustrated inFIG. 1 , and described above, is only exemplary andfuel injectors 30 of the current disclosure may be used with any configuration and layout of GTE 100. -
FIG. 2 is a perspective view of an embodiment offuel injector 30 which may be coupled tocombustor 50.FIG. 3 is a cross-sectional view offuel injector 30 schematically illustrated as being coupled tocombustor 50. In the description that follows, reference will be made to bothFIGS. 2 and 3 .Fuel injector 30 may be a single fuel injector or a dual fuel injector. A dual fuel injector is an injector that is configured to deliver different types of fuel (for example, gaseous and liquid fuel) to thecombustor 50.Fuel injector 30 extends from afirst end 12 to asecond end 14 along alongitudinal axis 88. As illustrated inFIG. 2 , thefuel injector 30 may have a shape resembling the frustum of a cone proximate thefirst end 12. Thefirst end 12 of thefuel injector 30 may be coupled tocombustor 50, and thesecond end 14 of thefuel injector 30 may extend into enclosure 72 (seeFIG. 1 ). As is known in the art,combustor 50 is an annular chamber, bounded by aliner 52, located aroundengine axis 98 of GTE 100 (seeFIG. 1 ). - Compressed air from
enclosure 72 entersfuel injector 30 through one ormore inlet openings second end 14 offuel injector 30. In some embodiments, these inlet openings may be ring-shaped openings annularly positioned aroundlongitudinal axis 88. However inlet openings of other shapes are also contemplated. For instance, in some embodiments,inlet openings longitudinal axis 88. Althoughinlet openings longitudinal axis 88. Because of this larger opening area, the quantity (volume/time, mass flow rate, etc.) of air entering thefuel injector 30 through inlet opening 16 a will be larger than that entering through inlet opening 18 a. At thesecond end 14, one or both ofinlet openings fuel injector 30. In some embodiments, theinlet openings fuel injector 30 through theseinlet openings - Compressed air that enters through inlet opening 16 a flows through a
central cavity 16 of thefuel injector 30.Central cavity 16 is a centrally located passageway that extends along thelongitudinal axis 88 from the inlet opening 16 a at thesecond end 14 to anexit opening 16 b at thefirst end 12. Theexit opening 16 b directs the compressed air in thecentral cavity 16 into thecombustor 50.Exit opening 16 b may be centrally positioned at thefirst end 12 of thefuel injector 30 around thelongitudinal axis 88. In some embodiments, thecentral cavity 16 may be cylindrically shaped and have a substantially constant diameter from thefirst end 12 to thesecond end 14. However, in some embodiments, thecentral cavity 16 may have a generally convergent shape such that the diameter of thecentral cavity 16 at thefirst end 12 is smaller than the diameter at thesecond end 14. In some embodiments, thecentral cavity 16 may converge substantially uniformly along an entire length of thefuel injector 30. However in some embodiments, thecentral cavity 16 may only converge along a portion of its length. For example, only a portion of the length of thecentral cavity 16 proximatefirst end 12 may be convergent while the remaining portion (that is, proximate the second end 14) of thecentral cavity 16 may be substantially cylindrical. The angle of convergence may depend upon the application. In some embodiments, the angle of convergence may be such that the diameter of thecentral cavity 16 at thefirst end 12 is 2-3% smaller than its diameter at thesecond end 14. A convergentcentral cavity 16 increases the velocity of the compressed air as it flows therethrough. - A
fuel nozzle 26 may be positioned at thesecond end 14 of thecentral cavity 16 to direct a fuel into thecentral cavity 16. Afuel pipe 24 may direct the fuel into thefuel nozzle 26. In general,fuel pipe 24 and thefuel nozzle 26 may direct any type of fuel into thecentral cavity 16. In some embodiments a gaseous fuel may be directed into thecentral cavity 16 through thefuel nozzle 26. In some embodiments, this gaseous fuel may be a high calorific fuel gas (such as, for example, natural gas, oil well gas, coal gas, etc.). This fuel may mix with compressed air entering thecentral cavity 16 through the inlet opening 16 a and create a premixed fuel-air mixture incentral cavity 16. The premixed fuel-air mixture travels downstream and enters thecombustor 50 through exit opening 16 b to undergo combustion. In embodiments where thecentral cavity 16 is convergent, the linear velocity of the fuel-air mixture increases as it travels towards the convergent portion. The increased linear velocity forces the ignited fuel-air mixture away from thefuel injector 30 and thereby assists in reducing flashback. - Compressed air that enters the
fuel injector 30 through inlet opening 18 a flows through aninner air passage 18 and enters thecombustor 50 through anexit opening 18 b at thefirst end 12.Exit opening 18 b of theinner air passage 18 is an annularly shaped opening positioned radially outwards of exit opening 16 b of thecentral cavity 16.Inner air passage 18 is an annular passageway symmetrically disposed about thelongitudinal axis 88, and positioned radially outwards of thecentral passageway 16. The compressed air from theinner air passage 18 flows into thecombustor 50 around the premixed fuel-air mixture that enters the combustor 50 from thecentral cavity 16. At the outlet offuel injector 30, the compressed air from theinner air passage 18 acts as a shroud around the premixed fuel-air mixture from thecentral cavity 16. The relative size of theinlet openings combustor 50 through theinner air passage 18 is sufficient to act as a shroud around the premixed fuel-air mixture (from the central cavity 16) without diluting the concentration of the fuel in the fuel-air mixture. The shape of theinner air passage 18 may also be configured to reduce the mixing of the air from theinner air passage 18 with the premixed fuel-air mixture from thecentral cavity 16. - Because of the generally conical shape of the
fuel injector 30 proximate thefirst end 12, theinner air passage 18 may progressively converge towards thelongitudinal axis 88 as it approaches theexit opening 18 b. That is, the radial distance of theinner air passage 18 from thelongitudinal axis 88 may decrease as theinner air passage 18 extends towards theexit opening 18 b. In some embodiments, as illustrated inFIG. 3 , only a portion of the length of theinner air passage 18, proximate thefirst end 12, may have a convergent shape. However, it is contemplated that in some embodiments, substantially an entire length of the inner air passage 18 (from thesecond end 14 to the first end 12) may be convergent. The gradually decreasing radial distance of theinner air passage 18 will decrease the cross-sectional area of the passage as it approaches theexit opening 18 b. The decreasing cross-sectional area will increase the linear velocity of the compressed air in theinner air passage 18 as it moves towards theexit opening 18 b. The decreasing radial distance will increase the spin or the angular velocity of the compressed air in theinner air passage 18 as it travels towards theexit opening 18 b. Because of the principle of conservation of angular momentum, the compressed air exiting theexit opening 18 b with increased angular velocity will move outwardly in a direction away from thelongitudinal axis 88. The convergent shape of theinner air passage 18 thus reduces the tendency of the compressed air from theinner air passage 18 to mix with, and dilute, the premixed fuel-air mixture from thecentral cavity 16 immediately upon exit into thecombustor 50. It should be noted that a convergent shape of theinner air passage 18 is not a requirement, and in some embodiments, theinner air passage 18 may not be convergent. In some embodiments,inner air passage 18 may includeswirler vanes 22 positioned thereon. Theseswirler vanes 22 may impart a swirl to the compressed air as it travels towards thecombustor 50. -
Fuel injector 30 also includes an annularly shapedouter passage 32 disposed radially outwards of theinner air passage 18. Theouter passage 32 may extend from an inlet opening 32 a proximate thesecond end 14 to an annularly shaped exit opening 32 b positioned radially outwards exit opening 18 b ofinner air passage 18. The inlet opening 32 a may open into anannular chamber 34 disposed at thesecond end 14 of thefuel injector 30.Annular chamber 34 may be an annular cavity that extends around thefuel injector 30 at thesecond end 14. Theannular chamber 34 may include multiple inlet ports (withfluid conduits 36 coupled thereto) to direct one or more fluids into theannular chamber 34. In some embodiments, these multiple inlet ports may include afirst inlet port 34 a, asecond inlet port 34 b, athird inlet port 34 c, and afourth inlet port 34 d. Thefirst inlet port 34 a may be configured to deliver a gaseous fuel, asecond inlet port 34 b may be configured to direct a liquid fuel, athird inlet port 34 c may be configured to direct shop air, and afourth inlet port 34 d may be configured to direct steam (or water) into theannular chamber 34. During operation ofGTE 100, one or more fluids may be selectively directed into theannular chamber 34 through these multiple inlet ports at the same time. For example, in some applications a liquid fuel and shop air may be directed into theannular chamber 34, at the same time, during starting of theGTE 100. AfterGTE 100 reaches a desired speed, the liquid fuel and shop air supply may be stopped, and gaseous fuel may be directed into theannular chamber 34. The fluid (liquid fuel, gaseous fuel, shop air, steam, etc.) in theannular chamber 34 may travel through theouter passage 32 and enter thecombustor 50 through exit opening 32 b. - Compressed air from
enclosure 72 also enters thecombustor 50 through anair swirler 28 positioned circumferentially outwardly of thefuel injector 30 at thefirst end 12.Air swirler 28 may include one or more blades or vanes shaped to induce a swirl to the compressed air passing therethough. Although theair swirler 28 illustrated inFIG. 3 is an axial air swirler, any type of air swirler known in the art (for example, radial air swirler) may be used. As the compressed air from theenclosure 72 flows into thecombustor 50 through theair swirler 28, a swirl will be induced to the air. This swirled air will spin outwardly and move towards the outer walls ofcombustor 50. Since air swirlers and their role in the functioning ofGTE 100 are known in the art, for the sake of brevity,air swirler 28 is not discussed in detail herein. - In some embodiments, a portion of the length (or even the entire length) of the
outer passage 32 may converge towards thelongitudinal axis 88 as it approaches theexit opening 32 b. That is, the radial distance (and hence the cross-sectional area) of theouter passage 32 from thelongitudinal axis 88 may decrease towards thecombustor 50. As explained earlier with reference to theinner air passage 18, this decreasing radial distance increases the linear and angular velocity of the fluid as it travels through theouter passage 32. Due to the increased angular velocity, the fluid exiting theexit opening 32 b will spin outwardly and move in a direction away from the longitudinal axis 88 (because of conservation of angular momentum). This outwardly moving fluid will meet and mix with the swirled air stream from theair swirler 28 and rapidly mix. When the fluid directed through theouter passage 32 is a fuel (liquid or gaseous), the mixing of the fuel and air reduces the flame temperature, and thereby the NO production, in thecombustor 50. The angle of convergence (the angle between theouter passage 32 and the longitudinal axis 88) of theouter passage 32 may be any value and may depend upon the application. In some exemplary embodiments, an angle of convergence of between about 20° and 80° may be suitable. It should be noted that, althoughFIG. 3 illustrates the thickness of the convergentouter passage 32 and the convergentinner air passage 18 as decreasing towards thefirst end 12, this is not a requirement. That is, in some embodiments, a convergent passage (outer passage 32 and/or inner air passage 18) may be a passageway with a constant thickness along its length that angles towards thelongitudinal axis 88. - In some embodiments, some or all of the multiple ports (first, second, third, and
fourth port annular chamber 34 such that the fluids enter theannular chamber 34 tangentially to induce a spin to the fluid. The induced spin may assist in thorough mixing of the fluid with gases in thecombustor 50. A fluid may be tangentially directed into theannular chamber 34 by tangentially positioning a port or by adapting the shape of the port (for example, a curved port, angled port, etc.) for tangential entry. Although a cylindrically shapedannular chamber 34 is illustrated inFIGS. 2 and 3 , in some embodiments,annular chamber 34 may be a toroidal (snail shell shaped) cavity in which the area of the cavity decreases with distance around thelongitudinal axis 88. In such an embodiment, as a fluid enters the toroidalannular chamber 34 and travels around the gradually narrowing cavity, a spin is introduced to the fluid. - Although the
annular chamber 34 is illustrated as having four inlet ports, this is only exemplary. Other embodiments offuel injectors 30 may have a different number of inlet ports. For example, in some embodiments offuel injector 30, only one inlet port may be provided to direct a gaseous fuel or a liquid fuel into theannular chamber 34, and in another embodiment two inlet ports may be provided to direct a liquid fuel and shop air into theannular chamber 34. Any type of gaseous fuel (natural gas, coal gas, etc.) and liquid fuel (for example, kerosene, diesel fuel, etc.) may be directed into theannular chamber 34 through the first andsecond ports first port 34 a and thefuel nozzle 26, while in other embodiments, different gaseous fuels may be provided through thefirst port 34 a and thefuel nozzle 26.Third port 34 c may direct shop air to theannular chamber 34. The shop air may be air compressed using a different compressor than thatcompressor system 10 of theGTE 100. In some embodiments, shop air may be directed to thecombustor 50 only during lightoff of theGTE 100. During lightoff, the shop air may have a higher pressure than the compressed air of thecompressor system 10. The shop air may assist in atomization of the liquid fuel when liquid fuel is directed into theannular chamber 34. The steam directed into theannular chamber 34 through thefourth port 34 d may assist in reducing the flame temperature (and thereby reduce NO production) in thecombustor 50. - A common concern with fuel injectors is the cross-contamination of fuel delivery lines during operation. During operation, combustion driven turbulent pressure fluctuations may induce small pressure variations in the vicinity of
different fuel injectors 30 in thecombustor 50. These pressure differences may induce fuel to migrate into fuel lines in lower pressure regions and create carbonaceous deposits therein. For example, whenGTE 100 operates with liquid fuel delivered throughouter passage 32, thecentral cavity 16 may only direct compressed air (from inlet opening 16 a) to thecombustor 50. Absent the compressed air supply through exit opening 18 b that forms a shroud (or an air shell, air curtain, etc.) around exit opening 16 b, pressure fluctuations in thecombustor 50 may cause the liquid fuel to enter the central cavity 16 (and the liquid fuel nozzle 26) and ignite or decompose therein to cause coking. However, the compressed air supply through outlet opening 18 b circumferentially disposed around outlet opening 16 b prevents the liquid fuel from migrating into thecentral cavity 16. The increased angular momentum of the liquid fuel emanating from the outlet opening 32 b of theouter passage 32 will also cause the liquid fuel to move in a direction away from thelongitudinal axis 88 and assist in keeping the liquid fuel away from thecentral cavity 16. In a similar manner, the compressed air supply through the outlet opening 18 b shrouds and prevents the premixed fuel-air mixture from thecentral cavity 16 from entering and depositing in theouter passage 32. - The disclosed fuel injector may be applicable to any turbine engine. In one embodiment of the fuel injector, two separate streams of fuel are directed into the combustor through the fuel injector, and the respective fuel outlets are positioned to reduce cross-contamination. A compressed air stream is configured to separate the two fuel outlets from each other. In some embodiments, the fuel through the fuel outlets is directed to the combustor in a manner to reduce flashback. The operation of a gas turbine engine with an embodiment of a disclosed fuel injector will now be described.
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FIG. 4 is a flowchart that illustrates an exemplary application offuel injector 30.GTE 100 may be started with a liquid fuel directed tocombustor 50 throughouter passage 32, and transitioned to a gaseous fuel directed tocombustor 50 throughcentral cavity 16 at a nominal power. During startup, compressed air fromenclosure 72 is directed into thecombustor 50 through theair swirler 28 and through one ormore fuel injectors 30 coupled to the combustor 50 (step 110). The compressed air supplied though eachfuel injector 30 flows through thecentral cavity 16 and theinner air passage 18 of thefuel injector 30. In the current application, the total amount of compressed air that is directed into thecombustor 50 through thefuel injectors 30 and theair swirler 28 is termed as “injection air.” In atypical GTE 100, about 15-25% of the total air directed to thecombustor 50 is injection air. The remaining amount of compressed air (that is, 75-85%) enters thecombustor 50 through other paths (for instance, as cooling air supply through perforations on theliner 52, etc.). In an exemplary embodiment of thefuel injector 30, about 15% of the injection air enters thecombustor 50 through thefuel injectors 30, and the remaining amount (about 85%) enters thecombustor 50 through theair swirler 28. Of the portion of the injection air that enters thecombustor 50 through the fuel injectors 30 (about 15% of the injection air), about 5% flows through thecentral cavity 16, and the remaining amount (about 10%) flows through theouter air passage 18. That is, in such an exemplary embodiment offuel injector 30, the amount (volume/time, flow rate, etc.) of compressed air flowing through theinner air passage 18 is about 2 (that is, about 10%/about 5%) times higher than the amount of air flowing in through thecentral cavity 16. In general, the amount of compressed air flowing through theinner air passage 18 may be between about 1.5 and 4 times the amount of air flowing in through thecentral cavity 16. The compressed air exiting into the combustor 50 from theinner air passage 18 surrounds theexit opening 16 b of thecentral cavity 16, and acts as a shroud around the compressed air from thecentral cavity 16. - Liquid fuel is also directed into the
combustor 50, around the compressed air supply from theinner air passage 18, through outer passage 32 (step 120). In some embodiments, due to the shape of theouter passage 32 that directs the liquid fuel to thecombustor 50, the angular velocity and the linear velocity of the liquid fuel may increase as the fuel travels towards thecombustor 50. The increased angular velocity may cause the liquid fuel that exits into thecombustor 50 to be flung outwards towards the combustor walls and away from thecentral cavity 16. The outwardly traveling liquid fuel may reduce the possibility of the liquid fuel migrating into thecentral cavity 16 and decomposing therein. The compressed air supply from theinner air passage 18 may also act as an air curtain that prevents the liquid fuel from migrating into thecentral cavity 16. - Within the
combustor 50, the outwardly moving liquid fuel stream will mix with the portion of injection air flowing into thecombustor 50 through the air swirler 28 (step 130). The mixed liquid fuel and air will ignite and travel outwards towards the combustion walls and spread around the combustor 50 (step 140). TheGTE 100 is then accelerated to a desired power value (idle speed, a nominal load, etc.) using the liquid fuel (step 150). After the desired power value is reached, gaseous fuel may be injected into thecentral cavity 16 through the fuel nozzle 26 (step 160). This gaseous fuel mixes with the portion of the injection air that flows through thecentral cavity 16 and creates a premixed fuel-air mixture (step 170). This premixed fuel-air mixture enters thecombustor 50, shrouded by the compressed air supply from the circumferentially disposed exit opening 18 b (step 180). Within the combustor, the premixed fuel-air mixture ignites (step 190). - The liquid fuel supply through the
outer passage 32 may now be stopped (step 200). The compressed air stream surrounding the premixed fuel-air mixture from thecentral cavity 16 prevents the fuel-air mixture from migrating upwards into theouter passage 18 and decomposing therein. In some embodiments, the shape of thecentral cavity 16 may be configured to increase the linear velocity of the premixed fuel-air mixture entering thecombustor 50. The increased linear velocity of the fuel-air mixture assists in moving the ignited mixture away from thefuel injector 30 and reducing the possibility of flashback. In some embodiments, after terminating the liquid fuel supply viaouter passage 32, gaseous fuel may be supplied to thecombustor 50 through theouter passage 32. In some embodiments, when the flame temperature within thecombustor 50 causes the NOx emissions to increase above a desired value, steam may be directed into thecombustor 50 through theouter passage 32 to reduce the flame temperature. In some embodiments, along with the liquid fuel, shop air may also be directed into thecombustor 50 through theouter air passage 32 to provide additional air for combustion. The ability to direct multiple fuels and other fluids into thecombustor 50 through thefuel injector 30 increases the versatility of the fuel injector 40 while reducing NOx emissions. - It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed fuel injector. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed fuel injector. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.
Claims (18)
1. A fuel injector for a gas turbine engine comprising:
an injector housing including a central cavity extending along a longitudinal axis from an upstream end to a downstream end, the downstream end of the central cavity including an exit opening configured to fluidly couple the central cavity to a combustor of the gas turbine engine;
a fuel nozzle at the upstream end of the central cavity, the fuel nozzle being configured to direct a first fuel into the central cavity;
an annular air inlet of the central cavity disposed circumferentially about the fuel nozzle at the upstream end of the central cavity;
an annular air discharge outlet circumferentially disposed about the exit opening of the central cavity; and
an annular fuel discharge outlet circumferentially disposed about the air discharge outlet, the fuel discharge outlet being configured to discharge a second fuel into the combustor circumferentially around the air discharge outlet.
2. The fuel injector of claim 1 , further including an annular inner passageway extending from an inlet opening at the upstream end to the annular air discharge outlet at the downstream end, the inner passageway being disposed radially outwards of and symmetrically about the central cavity.
3. The fuel injector of claim 2 , wherein at least a portion of the inner passageway forms a convergent passageway.
4. The fuel injector of claim 2 , further including an annular outer passageway extending from the upstream end to the fuel discharge outlet at the downstream end, the outer passageway being disposed symmetrically about the central cavity and radially outwards the inner passageway.
5. The fuel injector of claim 4 , wherein at least a portion of the outer passageway forms a convergent passageway.
6. The fuel injector of claim 4 , further including an annular chamber extending around the upstream end of the injector housing, wherein the outer passageway is fluidly coupled to the annular chamber at the upstream end.
7. The fuel injector of claim 6 , further including a plurality of inlet ports coupled to the annular chamber, wherein a first inlet port of the plurality of inlet ports is configured to direct the second fuel into the outer passageway.
8. The fuel injector of claim 7 , wherein the second fuel is a liquid fuel and the plurality of inlet ports includes a second inlet port configured to direct a gaseous fuel into the outer passageway.
9. The fuel injector of claim 8 , wherein the plurality of inlet ports includes a third inlet port configured to direct steam into the outer passageway.
10. The fuel injector of claim 1 , wherein at least a portion of the central cavity is a convergent passageway.
11. A method of operating a gas turbine engine comprising:
directing a premixed fuel-air mixture into a combustor of the gas turbine engine through a central cavity of a fuel injector, the premixed fuel-air mixture being a mixture of a first fuel and a first quantity of compressed air, the central cavity extending from an upstream end to a downstream end fluidly coupled to the combustor;
directing a second quantity of compressed air into the combustor circumferentially around the premixed fuel-air mixture; and
directing a second fuel into the combustor circumferentially around the second quantity of compressed air, wherein directing the second fuel includes increasing an angular velocity of the second fuel in the fuel injector.
14. The method of claim 13, wherein directing the premixed fuel-air mixture includes directing the first fuel into the upstream end of the central cavity, and directing the first quantity of compressed air into the central cavity circumferentially around the first fuel.
15. The method of claim 13, further including increasing an angular velocity and a linear velocity of the second quantity of compressed air in the fuel injector prior to directing the second quantity of compressed air into the combustor.
16. The method of claim 13, further including directing steam into the combustor circumferentially around the second quantity of compressed air.
17. A gas turbine engine, comprising:
a combustion system including a combustor; and
a fuel injector extending from an upstream end to a downstream end along a longitudinal axis, the fuel injector being coupled to the combustor at the downstream end, the fuel injector including:
a central cavity extending from the upstream end to a central opening at the downstream end, the central cavity being configured to direct a fuel into the combustor through the central opening;
an annular air discharge outlet circumferentially disposed about the central opening, the annular air discharge outlet being configured to direct compressed air into the combustor circumferentially around the fuel entering the combustor from the central cavity; and
an outer passageway circumferentially disposed about the central cavity, the outer passageway being configured to selectively direct a gaseous fuel and a liquid fuel into the combustor circumferentially around the compressed air from the air discharge outlet.
18. The gas turbine of claim 17 , wherein the outer passageway is fluidly coupled to an annular chamber that extends around the fuel injector at the upstream end, the annular chamber including a plurality of inlet ports coupled thereto, the plurality of inlet ports including a first inlet port configured to direct the gaseous fuel into the outer passageway, a second inlet port configured to direct the liquid fuel into the outer passageway, and a third inlet port configured to direct steam into the outer passageway.
19. The gas turbine of claim 17 , wherein at least a portion of the central cavity is a convergent passageway.
20. The gas turbine engine of claim 17 , wherein at least a portion of the outer passageway is a convergent passageway.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/327,131 US20130152594A1 (en) | 2011-12-15 | 2011-12-15 | Gas turbine and fuel injector for the same |
Applications Claiming Priority (1)
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US13/327,131 US20130152594A1 (en) | 2011-12-15 | 2011-12-15 | Gas turbine and fuel injector for the same |
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Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4977740A (en) * | 1989-06-07 | 1990-12-18 | United Technologies Corporation | Dual fuel injector |
US5218824A (en) * | 1992-06-25 | 1993-06-15 | Solar Turbines Incorporated | Low emission combustion nozzle for use with a gas turbine engine |
US5784875A (en) * | 1995-11-27 | 1998-07-28 | Innovative Control Systems, Inc. | Water injection into a gas turbine using purge air |
US5836163A (en) * | 1996-11-13 | 1998-11-17 | Solar Turbines Incorporated | Liquid pilot fuel injection method and apparatus for a gas turbine engine dual fuel injector |
US6363726B1 (en) * | 2000-09-29 | 2002-04-02 | General Electric Company | Mixer having multiple swirlers |
US20040035114A1 (en) * | 2002-08-22 | 2004-02-26 | Akinori Hayashi | Gas turbine combustor, combustion method of the gas turbine combustor, and method of remodeling a gas turbine combustor |
US20040219079A1 (en) * | 2003-01-22 | 2004-11-04 | Hagen David L | Trifluid reactor |
US20070003897A1 (en) * | 2005-06-24 | 2007-01-04 | Hiromi Koizumi | Burner, gas turbine combustor, burner cooling method, and burner modifying method |
US20080302105A1 (en) * | 2007-02-15 | 2008-12-11 | Kawasaki Jukogyo Kabushiki Kaisha | Combustor of a gas turbine engine |
-
2011
- 2011-12-15 US US13/327,131 patent/US20130152594A1/en not_active Abandoned
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4977740A (en) * | 1989-06-07 | 1990-12-18 | United Technologies Corporation | Dual fuel injector |
US5218824A (en) * | 1992-06-25 | 1993-06-15 | Solar Turbines Incorporated | Low emission combustion nozzle for use with a gas turbine engine |
US5784875A (en) * | 1995-11-27 | 1998-07-28 | Innovative Control Systems, Inc. | Water injection into a gas turbine using purge air |
US5836163A (en) * | 1996-11-13 | 1998-11-17 | Solar Turbines Incorporated | Liquid pilot fuel injection method and apparatus for a gas turbine engine dual fuel injector |
US6363726B1 (en) * | 2000-09-29 | 2002-04-02 | General Electric Company | Mixer having multiple swirlers |
US20040035114A1 (en) * | 2002-08-22 | 2004-02-26 | Akinori Hayashi | Gas turbine combustor, combustion method of the gas turbine combustor, and method of remodeling a gas turbine combustor |
US20040219079A1 (en) * | 2003-01-22 | 2004-11-04 | Hagen David L | Trifluid reactor |
US20070003897A1 (en) * | 2005-06-24 | 2007-01-04 | Hiromi Koizumi | Burner, gas turbine combustor, burner cooling method, and burner modifying method |
US20080302105A1 (en) * | 2007-02-15 | 2008-12-11 | Kawasaki Jukogyo Kabushiki Kaisha | Combustor of a gas turbine engine |
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AS | Assignment |
Owner name: SOLAR TURBINES INCORPORATED, CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:OSKAM, GARETH W.;REEL/FRAME:027393/0149 Effective date: 20111206 |
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STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |