US20180238548A1 - Passive purge injectors - Google Patents
Passive purge injectors Download PDFInfo
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- US20180238548A1 US20180238548A1 US15/439,014 US201715439014A US2018238548A1 US 20180238548 A1 US20180238548 A1 US 20180238548A1 US 201715439014 A US201715439014 A US 201715439014A US 2018238548 A1 US2018238548 A1 US 2018238548A1
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- circuit
- air
- gaseous fuel
- fuel
- outlet
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Classifications
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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
- F23R3/02—Continuous combustion chambers using liquid or gaseous fuel characterised by the air-flow or gas-flow configuration
- F23R3/04—Air inlet arrangements
- F23R3/10—Air inlet arrangements for primary air
- F23R3/12—Air inlet arrangements for primary air inducing a vortex
- F23R3/14—Air inlet arrangements for primary air inducing a vortex by using swirl vanes
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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
- F23R3/283—Attaching or cooling of fuel injecting means including supports for fuel injectors, stems, or lances
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D11/00—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space
- F23D11/24—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space by pressurisation of the fuel before a nozzle through which it is sprayed by a substantial pressure reduction into a space
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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
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D2204/00—Burners adapted for simultaneous or alternative combustion having more than one fuel supply
- F23D2204/10—Burners adapted for simultaneous or alternative combustion having more than one fuel supply gaseous and liquid fuel
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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
- F23R2900/00—Special features of, or arrangements for continuous combustion chambers; Combustion processes therefor
- F23R2900/00004—Preventing formation of deposits on surfaces of gas turbine components, e.g. coke deposits
Definitions
- the present disclosure relates to injectors, and more particularly to multiple circuit injectors with passive purge for inactive circuits.
- Dual-fuel gas-turbine fuel injectors often require active purging of the idle fuel circuit with air in order to prevent unwanted fouling and liquid fuel collecting in the idle gas circuit.
- This active purging requires costly additional subsystems, which can also add a parasitic efficiency loss to the engine.
- Passive-purge concepts have been used to obviate the need for active purging; however, traditional passive-purge injectors only function for a relatively narrow range of Wobbe Index fuels around the design point.
- the Wobbe Index is a way of comparing energy density of one fuel to another, and varies proportionally with calorific value and inversely with the square root of specific gravity.
- a fuel with a higher Wobbe Index value can be supplied at a lower flow rate than a fuel with a lower Wobbe Index value. If gaseous fuel is used with a Wobbe Index value sufficiently lower than the design point for a given traditional passive purge injector, then the gaseous fuel will tend to backflow into the diffuser cavity and lead to possible engine damage.
- a method of injecting fuel in a gas turbine engine includes injecting gaseous fuel from a gaseous fuel circuit of an injector in a first mode, wherein flow of gaseous fuel from the gaseous fuel circuit constricts air flow from an air circuit outboard or inboard of the gaseous fuel circuit in the first mode.
- the method includes injecting liquid fuel from a liquid fuel circuit in a second mode, wherein the second mode includes idling flow in the gaseous fuel circuit and flowing air through the air circuit for passive purge to prevent liquid fuel from migrating into the gaseous fuel circuit. Switching the air circuit between constricted flow in the first mode and unconstricted flow in the second mode is accomplished by activating or idling the gaseous fuel circuit, respectively.
- Injecting gaseous fuel includes injecting a gaseous fuel that lies within a range of different Wobbe Index values ranging from a first Wobbe Index value to a second Wobbe index value, wherein regardless of where the gaseous fuel falls in the range of different Wobbe Index values, it does not prevent operation in the first mode constricting air flow from the air circuit in the first mode, and wherein regardless of where the gaseous fuel falls in the range of different Wobbe Index values, it does not prevent operation in the second mode preventing liquid fuel migrating into the gas circuit in the second mode.
- the first Wobbe Index value and the second Wobbe Index value can differ by a factor up to 3. It is also contemplated that the first Wobbe Index value and the second Wobbe Index value can differ by a factor of 3 or more.
- Constricting air flow from the air circuit in the first mode can include flowing gaseous fuel from the gaseous fuel circuit in a flow path that crosses an outlet opening of the air circuit, restricting how much air can flow through the air circuit.
- Flowing gaseous fuel in a flow path that crosses the outlet opening of the air circuit can include flowing the gaseous fuel from a converging lip bounding an outlet of the gaseous fuel circuit to a converging lip bounding the outlet opening of the air circuit.
- the converging lip bounding the outlet of the gaseous fuel circuit can impart a momentum vector on gas flowing out of the gaseous fuel circuit to at least partially block off the outlet opening of the air circuit.
- Back-flowing gaseous fuel into a compressor discharge cavity supplying air to the air circuit can be prevented in the first mode.
- some air can be discharged through the constricted air circuit, and gaseous fuel from the gaseous fuel circuit and air from the air circuit can both exit the injector through a common exit passage.
- Constricting air flow from the air circuit in the first mode can include constricting up to 65% of the air flow through the air circuit compared to air flow through the air circuit in the second mode.
- Flowing air through the air circuit for passive purge can include impinging air from the air circuit onto an outer surface of a liquid injector inboard of the gaseous fuel circuit.
- Passive purge to prevent liquid fuel from migrating into the gaseous fuel circuit can include scrubbing liquid fuel from a conical surface of a liquid injector inboard of the gaseous flow circuit with impinging air flow from the air circuit.
- Impinging air from the air circuit onto the outer surface of the liquid injector can include issuing air from an outlet opening of the air circuit defined between two converging lips of the injector.
- Back-flowing liquid fuel into a compressor discharge cavity supplying air to the air circuit can be prevented in the second mode. It is also contemplated that migrating liquid fuel into the gaseous fuel circuit and/or growing carbon on a conical surface of a liquid injector inboard of the gaseous flow circuit can be prevented in the second mode.
- a fuel injector can include a liquid injector having a liquid fuel circuit, a gaseous fuel circuit outboard or inboard of the liquid fuel circuit, and an air circuit outboard or inboard of the gaseous fuel circuit.
- the gaseous fuel circuit and liquid fuel circuit can be configured to operate in the two modes described above.
- a converging lip can bound an outlet of the gaseous fuel circuit, wherein the converging lip is configured to impart a momentum vector on gas flowing out of the gaseous fuel circuit to at least partially block off the outlet opening of the air circuit in the first mode.
- a fuel injecting arrangement includes a body comprising:
- a converging lip can bound an outlet of the gaseous fuel circuit forming a conical shape, wherein the converging lip is configured to impart a momentum vector on gas flowing out of the gaseous fuel circuit to at least partially block off the outlet opening of the air circuit in the first mode, such that gaseous fuel flowing through the gaseous fuel circuit is directed at least partially radially inwardly prior to being mixed with air.
- a fuel injecting arrangement includes a body comprising:
- FIG. 1 is a cross-sectional side elevation view of an exemplary embodiment of an injector constructed in accordance with the present disclosure, showing the injector in a first mode with gaseous fuel issuing from the gaseous fuel circuit;
- FIG. 2 is a cross-sectional side elevation view of the injector of FIG. 1 , showing the injector in a second mode with the gaseous fuel circuit idle, wherein passive purging of liquid fuel is provided by air from the air circuit.
- FIG. 1 a partial view of an exemplary embodiment of an injector in accordance with the disclosure is shown in FIG. 1 and is designated generally by reference character 100 .
- FIG. 2 Other aspects of injectors in accordance with the disclosure are provided in FIG. 2 , as will be described.
- the systems and methods described herein can be used to provide passive purge of liquid fuel in dual-fuel, e.g., gaseous and liquid fuel, injection for gas turbine engines over a wide range of Wobbe Index values for the gaseous fuel.
- Fuel injector 100 includes a liquid injector 102 having a liquid fuel circuit 104 (two or more liquid fuel circuits can be used, e.g., a primary for low power and a secondary high power), a gaseous fuel circuit 106 outboard of the liquid fuel circuit 104 , and an air circuit 108 outboard of the gaseous fuel circuit 106 .
- liquid fuel circuit 104 two or more liquid fuel circuits can be used, e.g., a primary for low power and a secondary high power
- a gaseous fuel circuit 106 outboard of the liquid fuel circuit 104
- an air circuit 108 outboard of the gaseous fuel circuit 106 .
- the gaseous fuel circuit 106 and liquid fuel circuit 104 are configured to operate in the two modes described below and shown respectively in FIG. 1 and FIG. 2 .
- a converging lip 110 bounds the outlet 112 of the gaseous fuel circuit 106 forming a conical shape.
- a method of injecting fuel in a gas turbine engine includes injecting gaseous fuel from a gaseous fuel circuit, e.g. gaseous fuel circuit 106 , of an injector, e.g., injector 100 .
- Flow of gaseous fuel from the gaseous fuel circuit constricts air flow from an air circuit, e.g. air circuit 108 , outboard of the gaseous fuel circuit in the first mode.
- the converging lip 110 is configured to impart a momentum vector, represented by the flow arrows in FIG.
- Constricting air flow from the air circuit in the first mode can include flowing gaseous fuel from the gaseous fuel circuit in a flow path that crosses an outlet opening, e.g. outlet opening 114 , of the air circuit, restricting how much air can flow through the air circuit, as indicated by the flow arrows in FIG. 1 .
- This can include flowing the gaseous fuel from converging lip 110 to a converging lip 116 bounding the outlet opening 114 of the air circuit, i.e. as shown in FIG. 1 by the flow arrows of gaseous fuel circuit 106 crossing outlet opening 114 from tip to tip of the lips 110 and 116 .
- a compressor discharge cavity e.g., the space designated by reference character 118 , supplies air to the air circuit.
- the flow patterns in the first mode By the flow patterns in the first mode, back-flowing gaseous fuel into the compressor discharge cavity 118 can be prevented. It is also contemplated that migrating fuel into the gaseous fuel circuit 106 and/or growing carbon on the conical surface 122 of the liquid injector 102 inboard of the gaseous flow circuit can be prevented in the second mode. In the first mode some air can be discharged through the constricted air circuit 108 , as indicated by the flow arrows in FIG. 1 in air circuit 108 , and gaseous fuel from the gaseous fuel circuit and air from the air circuit can both exit the injector through a common exit passage 120 . The amount of air constriction in the first mode will vary depending on the Wobbe Index of the gaseous fuel being used, with fuels at low end of allowable
- Constricting air flow from the air circuit in the first mode can include constricting up to 65% or more of the air flow through the air circuit compared to air flow through the air circuit in the second mode, which is described below.
- the method includes injecting liquid fuel from a liquid fuel circuit, e.g., liquid fuel circuit 104 , in the second mode as represented schematically in FIG. 2 by the droplets issuing from the outlet 113 of the liquid fuel circuit 104 .
- the second mode includes idling flow in the gaseous fuel circuit and flowing air through the air circuit for passive purge to prevent liquid fuel from migrating into the gaseous fuel circuit, as indicated by the flow arrows in air circuit 108 in FIG. 2 .
- Back-flowing liquid fuel into a compressor discharge cavity 118 can also be prevented in the second mode. Switching the air circuit between constricted flow in the first mode and unconstricted flow in the second mode is accomplished by activating or idling the gaseous fuel circuit, respectively.
- Flowing air through the air circuit for passive purge includes impinging air from the air circuit onto an outer surface 122 of the liquid injector 102 . This scrubs liquid fuel from a conical surface 122 with impinging air flow from the air circuit. Impinging air from the air circuit onto the outer surface of the liquid injector can include issuing air from an outlet opening, e.g., outlet opening 114 , of the air circuit defined between two converging lips, e.g. lips 110 and 116 , of the injector.
- the method includes injecting gaseous fuel that lies within a range of different Wobbe Index values ranging from a first Wobbe Index value to a second Wobbe Index value, wherein regardless of where the gaseous fuel falls within the range of different Wobbe Index values, it does not prevent operation in the first and second modes as described herein.
- the first Wobbe Index value and the second Wobbe Index value can differ by a factor up to 3 or more. For example, this allows use of a given fuel injector constructed in accordance with this disclosure in gas turbine engines at various locations where the gas supplies are very different from one another in Wobbe Index values, i.e., this allows for greater flexibility in what installations/locations the injectors can be used compared to traditional injectors.
- This also allows for switching, or gradual change in a given gas supply, from a first gaseous fuel supplied to the gaseous fuel circuit to a second gaseous fuel, wherein the first gaseous fuel has a different Wobbe Index value from the second gaseous fuel, i.e. this allows for greater operational flexibility than traditional injectors.
- a nominal value for the range of Wobbe Index could be for natural gas at 1370 BTU/scf (or anywhere in a wider range for natural gas of 1310-1390 BTU/scf), and the range can go down to 1 ⁇ 3 to 1 ⁇ 4 of that nominal value, for example for low BTU landfill gas (“BTU” refers to British thermal units (where 1 BTU equals 1055.06 Joules) and “scf” refers to standard cubic feet, an amount of natural gas contained at standard temperature and pressure in one cubic foot, where one cubic foot equals 0.0283 cubic meters).
- BTU refers to British thermal units (where 1 BTU equals 1055.06 Joules)
- scf refers to standard cubic feet, an amount of natural gas contained at standard temperature and pressure in one cubic foot, where one cubic foot equals 0.0283 cubic meters).
- switching from the first gaseous fuel to the second gaseous fuel does not prevent operation in the first mode constricting air flow from the air circuit in the first mode, and wherein switching from the first fuel to the second fuel does not prevent operation in the second mode preventing liquid fuel migrating into the gas circuit in the second mode.
- CFD computational fluid dynamics
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Abstract
Description
- The present disclosure relates to injectors, and more particularly to multiple circuit injectors with passive purge for inactive circuits.
- Dual-fuel gas-turbine fuel injectors often require active purging of the idle fuel circuit with air in order to prevent unwanted fouling and liquid fuel collecting in the idle gas circuit. This active purging requires costly additional subsystems, which can also add a parasitic efficiency loss to the engine. Passive-purge concepts have been used to obviate the need for active purging; however, traditional passive-purge injectors only function for a relatively narrow range of Wobbe Index fuels around the design point. The Wobbe Index is a way of comparing energy density of one fuel to another, and varies proportionally with calorific value and inversely with the square root of specific gravity. For a given energy output requirement, a fuel with a higher Wobbe Index value can be supplied at a lower flow rate than a fuel with a lower Wobbe Index value. If gaseous fuel is used with a Wobbe Index value sufficiently lower than the design point for a given traditional passive purge injector, then the gaseous fuel will tend to backflow into the diffuser cavity and lead to possible engine damage.
- The conventional techniques have been considered satisfactory for their intended purpose. However, there is an ever present need for improved passive purge injectors, specifically regarding the flexibility of the energy content in the gaseous fuel. This disclosure provides a solution for this problem.
- A method of injecting fuel in a gas turbine engine includes injecting gaseous fuel from a gaseous fuel circuit of an injector in a first mode, wherein flow of gaseous fuel from the gaseous fuel circuit constricts air flow from an air circuit outboard or inboard of the gaseous fuel circuit in the first mode. The method includes injecting liquid fuel from a liquid fuel circuit in a second mode, wherein the second mode includes idling flow in the gaseous fuel circuit and flowing air through the air circuit for passive purge to prevent liquid fuel from migrating into the gaseous fuel circuit. Switching the air circuit between constricted flow in the first mode and unconstricted flow in the second mode is accomplished by activating or idling the gaseous fuel circuit, respectively. Injecting gaseous fuel includes injecting a gaseous fuel that lies within a range of different Wobbe Index values ranging from a first Wobbe Index value to a second Wobbe index value, wherein regardless of where the gaseous fuel falls in the range of different Wobbe Index values, it does not prevent operation in the first mode constricting air flow from the air circuit in the first mode, and wherein regardless of where the gaseous fuel falls in the range of different Wobbe Index values, it does not prevent operation in the second mode preventing liquid fuel migrating into the gas circuit in the second mode.
- The first Wobbe Index value and the second Wobbe Index value can differ by a factor up to 3. It is also contemplated that the first Wobbe Index value and the second Wobbe Index value can differ by a factor of 3 or more.
- Constricting air flow from the air circuit in the first mode can include flowing gaseous fuel from the gaseous fuel circuit in a flow path that crosses an outlet opening of the air circuit, restricting how much air can flow through the air circuit. Flowing gaseous fuel in a flow path that crosses the outlet opening of the air circuit can include flowing the gaseous fuel from a converging lip bounding an outlet of the gaseous fuel circuit to a converging lip bounding the outlet opening of the air circuit. The converging lip bounding the outlet of the gaseous fuel circuit can impart a momentum vector on gas flowing out of the gaseous fuel circuit to at least partially block off the outlet opening of the air circuit. Back-flowing gaseous fuel into a compressor discharge cavity supplying air to the air circuit can be prevented in the first mode. In the first mode some air can be discharged through the constricted air circuit, and gaseous fuel from the gaseous fuel circuit and air from the air circuit can both exit the injector through a common exit passage. Constricting air flow from the air circuit in the first mode can include constricting up to 65% of the air flow through the air circuit compared to air flow through the air circuit in the second mode.
- Flowing air through the air circuit for passive purge can include impinging air from the air circuit onto an outer surface of a liquid injector inboard of the gaseous fuel circuit. Passive purge to prevent liquid fuel from migrating into the gaseous fuel circuit can include scrubbing liquid fuel from a conical surface of a liquid injector inboard of the gaseous flow circuit with impinging air flow from the air circuit. Impinging air from the air circuit onto the outer surface of the liquid injector can include issuing air from an outlet opening of the air circuit defined between two converging lips of the injector. Back-flowing liquid fuel into a compressor discharge cavity supplying air to the air circuit can be prevented in the second mode. It is also contemplated that migrating liquid fuel into the gaseous fuel circuit and/or growing carbon on a conical surface of a liquid injector inboard of the gaseous flow circuit can be prevented in the second mode.
- A fuel injector can include a liquid injector having a liquid fuel circuit, a gaseous fuel circuit outboard or inboard of the liquid fuel circuit, and an air circuit outboard or inboard of the gaseous fuel circuit. The gaseous fuel circuit and liquid fuel circuit can be configured to operate in the two modes described above. A converging lip can bound an outlet of the gaseous fuel circuit, wherein the converging lip is configured to impart a momentum vector on gas flowing out of the gaseous fuel circuit to at least partially block off the outlet opening of the air circuit in the first mode.
- In another aspect, a fuel injecting arrangement includes a body comprising:
-
- at least one liquid fuel circuit having at least one liquid fuel outlet;
- at least one air flow circuit having at least one air outlet positioned radially of the liquid fuel outlet; and
- a gaseous fuel circuit having a gaseous fuel outlet positioned radially of the at least one liquid fuel outlet and radially of the at least one air outlet, the fuel injecting arrangement being configured such that the air flow is constricted from flowing out the at least one air outlet that is immediately radially adjacent to the gaseous fuel outlet when gaseous fuel is flowing out from the gaseous fuel outlet, while also preventing back flow of gaseous fuel into the at least one air outlet that is immediately radially adjacent to the gaseous fuel outlet for a Wobbe Index ranging from a nominal value to a value that is ⅓ to ¼ of the nominal value. The fuel injecting arrangement is further configured such that when liquid fuel is flowing out from the at least one liquid fuel outlet and the gaseous fuel circuit is idle, air flowing from the at least one air outlet that is immediately radially adjacent to the gaseous fuel outlet prevents liquid from settling on the gaseous fuel outlet or back flowing into the gaseous flow circuit through the gaseous fuel outlet.
- A converging lip can bound an outlet of the gaseous fuel circuit forming a conical shape, wherein the converging lip is configured to impart a momentum vector on gas flowing out of the gaseous fuel circuit to at least partially block off the outlet opening of the air circuit in the first mode, such that gaseous fuel flowing through the gaseous fuel circuit is directed at least partially radially inwardly prior to being mixed with air.
- In another aspect a fuel injecting arrangement includes a body comprising:
-
- at least one liquid fuel circuit having at least one liquid fuel outlet;
- at least one air flow circuit having at least one air outlet positioned radially outward of the liquid fuel outlet; and
- a gaseous fuel circuit having a gaseous fuel outlet positioned radially between the at least one liquid fuel outlet the at least one air outlet, the gaseous fuel outlet having a frustoconical shape such that gaseous fuel flowing out from the gaseous fuel outlet is directed partially radially inwardly prior to being mixed with air.
- These and other features of the systems and methods of the subject disclosure will become more readily apparent to those skilled in the art from the following detailed description of the preferred embodiments taken in conjunction with the drawings.
- So that those skilled in the art to which the subject disclosure appertains will readily understand how to make and use the devices and methods of the subject disclosure without undue experimentation, preferred embodiments thereof will be described in detail herein below with reference to certain figures, wherein:
-
FIG. 1 is a cross-sectional side elevation view of an exemplary embodiment of an injector constructed in accordance with the present disclosure, showing the injector in a first mode with gaseous fuel issuing from the gaseous fuel circuit; and -
FIG. 2 is a cross-sectional side elevation view of the injector ofFIG. 1 , showing the injector in a second mode with the gaseous fuel circuit idle, wherein passive purging of liquid fuel is provided by air from the air circuit. - Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, a partial view of an exemplary embodiment of an injector in accordance with the disclosure is shown in
FIG. 1 and is designated generally byreference character 100. Other aspects of injectors in accordance with the disclosure are provided inFIG. 2 , as will be described. The systems and methods described herein can be used to provide passive purge of liquid fuel in dual-fuel, e.g., gaseous and liquid fuel, injection for gas turbine engines over a wide range of Wobbe Index values for the gaseous fuel. -
Fuel injector 100 includes aliquid injector 102 having a liquid fuel circuit 104 (two or more liquid fuel circuits can be used, e.g., a primary for low power and a secondary high power), agaseous fuel circuit 106 outboard of theliquid fuel circuit 104, and anair circuit 108 outboard of thegaseous fuel circuit 106. Those skilled in the art will readily appreciate that although depicted in the order described above, the circuits can be ordered withgaseous fuel circuit 106 inboard of theliquid fuel circuit 104, and with theair circuit 108 inboard of thegaseous fuel circuit 106 without departing from the scope of this disclosure. Thegaseous fuel circuit 106 andliquid fuel circuit 104 are configured to operate in the two modes described below and shown respectively inFIG. 1 andFIG. 2 . Aconverging lip 110 bounds theoutlet 112 of thegaseous fuel circuit 106 forming a conical shape. - In the first mode, a method of injecting fuel in a gas turbine engine includes injecting gaseous fuel from a gaseous fuel circuit, e.g.
gaseous fuel circuit 106, of an injector, e.g.,injector 100. Flow of gaseous fuel from the gaseous fuel circuit constricts air flow from an air circuit,e.g. air circuit 108, outboard of the gaseous fuel circuit in the first mode. Theconverging lip 110 is configured to impart a momentum vector, represented by the flow arrows inFIG. 1 , on gas flowing out of thegaseous fuel circuit 106 to at least partially block off the outlet opening 114 of theair circuit 108 in the first mode, such that gaseous fuel flowing through thegaseous fuel circuit 106 is directed at least partially radially inwardly prior to being mixed with air. - Constricting air flow from the air circuit in the first mode can include flowing gaseous fuel from the gaseous fuel circuit in a flow path that crosses an outlet opening, e.g. outlet opening 114, of the air circuit, restricting how much air can flow through the air circuit, as indicated by the flow arrows in
FIG. 1 . This can include flowing the gaseous fuel from converginglip 110 to aconverging lip 116 bounding the outlet opening 114 of the air circuit, i.e. as shown inFIG. 1 by the flow arrows ofgaseous fuel circuit 106 crossing outlet opening 114 from tip to tip of thelips reference character 118, supplies air to the air circuit. By the flow patterns in the first mode, back-flowing gaseous fuel into thecompressor discharge cavity 118 can be prevented. It is also contemplated that migrating fuel into thegaseous fuel circuit 106 and/or growing carbon on theconical surface 122 of theliquid injector 102 inboard of the gaseous flow circuit can be prevented in the second mode. In the first mode some air can be discharged through theconstricted air circuit 108, as indicated by the flow arrows inFIG. 1 inair circuit 108, and gaseous fuel from the gaseous fuel circuit and air from the air circuit can both exit the injector through acommon exit passage 120. The amount of air constriction in the first mode will vary depending on the Wobbe Index of the gaseous fuel being used, with fuels at low end of allowable - Wobbe Index range reducing air flow to near zero. Constricting air flow from the air circuit in the first mode can include constricting up to 65% or more of the air flow through the air circuit compared to air flow through the air circuit in the second mode, which is described below.
- With reference now to
FIG. 2 , the method includes injecting liquid fuel from a liquid fuel circuit, e.g.,liquid fuel circuit 104, in the second mode as represented schematically inFIG. 2 by the droplets issuing from theoutlet 113 of theliquid fuel circuit 104. The second mode includes idling flow in the gaseous fuel circuit and flowing air through the air circuit for passive purge to prevent liquid fuel from migrating into the gaseous fuel circuit, as indicated by the flow arrows inair circuit 108 inFIG. 2 . Back-flowing liquid fuel into acompressor discharge cavity 118 can also be prevented in the second mode. Switching the air circuit between constricted flow in the first mode and unconstricted flow in the second mode is accomplished by activating or idling the gaseous fuel circuit, respectively. - Flowing air through the air circuit for passive purge includes impinging air from the air circuit onto an
outer surface 122 of theliquid injector 102. This scrubs liquid fuel from aconical surface 122 with impinging air flow from the air circuit. Impinging air from the air circuit onto the outer surface of the liquid injector can include issuing air from an outlet opening, e.g., outlet opening 114, of the air circuit defined between two converging lips,e.g. lips - The method includes injecting gaseous fuel that lies within a range of different Wobbe Index values ranging from a first Wobbe Index value to a second Wobbe Index value, wherein regardless of where the gaseous fuel falls within the range of different Wobbe Index values, it does not prevent operation in the first and second modes as described herein. The first Wobbe Index value and the second Wobbe Index value can differ by a factor up to 3 or more. For example, this allows use of a given fuel injector constructed in accordance with this disclosure in gas turbine engines at various locations where the gas supplies are very different from one another in Wobbe Index values, i.e., this allows for greater flexibility in what installations/locations the injectors can be used compared to traditional injectors. This also allows for switching, or gradual change in a given gas supply, from a first gaseous fuel supplied to the gaseous fuel circuit to a second gaseous fuel, wherein the first gaseous fuel has a different Wobbe Index value from the second gaseous fuel, i.e. this allows for greater operational flexibility than traditional injectors. A nominal value for the range of Wobbe Index could be for natural gas at 1370 BTU/scf (or anywhere in a wider range for natural gas of 1310-1390 BTU/scf), and the range can go down to ⅓ to ¼ of that nominal value, for example for low BTU landfill gas (“BTU” refers to British thermal units (where 1 BTU equals 1055.06 Joules) and “scf” refers to standard cubic feet, an amount of natural gas contained at standard temperature and pressure in one cubic foot, where one cubic foot equals 0.0283 cubic meters).
- Since the Wobbe Index value of a fuel varies proportionally with calorific value and inversely with the square root of specific gravity, the lower the Wobbe Index value of a given fuel, the greater the flow rate of the fuel will have to be to maintain a desired energy output. In traditional injectors, switching fuels from a higher Wobbe Index value to a lower value would have been problematic because the flow rate for a low Wobbe Index fuel is typically high enough to upset the pressure balance with outboard air purge circuits, causing backflow of gaseous fuel into the purge air circuits. However, in injectors in accordance with this disclosure, switching from the first gaseous fuel to the second gaseous fuel does not prevent operation in the first mode constricting air flow from the air circuit in the first mode, and wherein switching from the first fuel to the second fuel does not prevent operation in the second mode preventing liquid fuel migrating into the gas circuit in the second mode. This is due to the flow patterns shown in
FIGS. 1 and 2 for the first and second modes, respectively. The air and gaseous fuel circuits can be designed for a given application to operate as described herein using computational fluid dynamics (CFD) analysis, modeling for two different Wobbe Index values in the gaseous fuel circuit to span the range of desired Wobbe Index values. - The methods and systems of the present disclosure, as described above and shown in the drawings, provide for passive purge in dual fuel injectors with superior properties including increased acceptable range in Wobbe Index for gaseous fuels compared to traditional passive purge injection, without back-flowing gaseous or liquid fuel into the compressor discharge cavity. While the apparatus and methods of the subject disclosure have been shown and described with reference to preferred embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the scope of the subject disclosure.
Claims (16)
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/439,014 US20180238548A1 (en) | 2017-02-22 | 2017-02-22 | Passive purge injectors |
EP18157925.1A EP3366999A1 (en) | 2017-02-22 | 2018-02-21 | Passive purge injectors |
JP2018029362A JP2018136116A (en) | 2017-02-22 | 2018-02-22 | Passive purge injector |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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US15/439,014 US20180238548A1 (en) | 2017-02-22 | 2017-02-22 | Passive purge injectors |
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US20180238548A1 true US20180238548A1 (en) | 2018-08-23 |
Family
ID=61274080
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US15/439,014 Abandoned US20180238548A1 (en) | 2017-02-22 | 2017-02-22 | Passive purge injectors |
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US (1) | US20180238548A1 (en) |
EP (1) | EP3366999A1 (en) |
JP (1) | JP2018136116A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20210172604A1 (en) * | 2019-12-06 | 2021-06-10 | United Technologies Corporation | High shear swirler with recessed fuel filmer |
US11808219B2 (en) | 2021-04-12 | 2023-11-07 | Pratt & Whitney Canada Corp. | Fuel systems and methods for purging |
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US20090224080A1 (en) * | 2008-03-04 | 2009-09-10 | Delavan Inc | Pure Air Blast Fuel Injector |
US20100162711A1 (en) * | 2008-12-30 | 2010-07-01 | General Electric Compnay | Dln dual fuel primary nozzle |
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CA1178452A (en) * | 1981-07-23 | 1984-11-27 | Robie L. Faulkner | Gas turbine engines |
DE19652899A1 (en) * | 1996-12-19 | 1998-06-25 | Asea Brown Boveri | Burner arrangement for a gas turbine |
US6123273A (en) * | 1997-09-30 | 2000-09-26 | General Electric Co. | Dual-fuel nozzle for inhibiting carbon deposition onto combustor surfaces in a gas turbine |
US7104070B2 (en) * | 2004-03-04 | 2006-09-12 | General Electric Company | Liquid fuel nozzle apparatus with passive water injection purge |
JP4728176B2 (en) * | 2005-06-24 | 2011-07-20 | 株式会社日立製作所 | Burner, gas turbine combustor and burner cooling method |
US8123150B2 (en) * | 2010-03-30 | 2012-02-28 | General Electric Company | Variable area fuel nozzle |
JP6474951B2 (en) * | 2013-04-10 | 2019-02-27 | 三菱日立パワーシステムズ株式会社 | Combustor |
-
2017
- 2017-02-22 US US15/439,014 patent/US20180238548A1/en not_active Abandoned
-
2018
- 2018-02-21 EP EP18157925.1A patent/EP3366999A1/en not_active Ceased
- 2018-02-22 JP JP2018029362A patent/JP2018136116A/en not_active Ceased
Patent Citations (5)
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US3285007A (en) * | 1963-11-11 | 1966-11-15 | Rolls Royce | Fuel injector for a gas turbine engine |
US5615555A (en) * | 1993-10-19 | 1997-04-01 | European Gas Turbines Limited | Dual fuel injector with purge and premix |
GB2373043A (en) * | 2001-03-09 | 2002-09-11 | Alstom Power Nv | Fuel injector for a dual fuel turbine engine |
US20090224080A1 (en) * | 2008-03-04 | 2009-09-10 | Delavan Inc | Pure Air Blast Fuel Injector |
US20100162711A1 (en) * | 2008-12-30 | 2010-07-01 | General Electric Compnay | Dln dual fuel primary nozzle |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20210172604A1 (en) * | 2019-12-06 | 2021-06-10 | United Technologies Corporation | High shear swirler with recessed fuel filmer |
US11378275B2 (en) * | 2019-12-06 | 2022-07-05 | Raytheon Technologies Corporation | High shear swirler with recessed fuel filmer for a gas turbine engine |
US11808219B2 (en) | 2021-04-12 | 2023-11-07 | Pratt & Whitney Canada Corp. | Fuel systems and methods for purging |
Also Published As
Publication number | Publication date |
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JP2018136116A (en) | 2018-08-30 |
EP3366999A1 (en) | 2018-08-29 |
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