US20190003713A1 - Air-shielded fuel injection assembly to facilitate reduced nox emissions in a combustor system - Google Patents
Air-shielded fuel injection assembly to facilitate reduced nox emissions in a combustor system Download PDFInfo
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- US20190003713A1 US20190003713A1 US16/132,430 US201816132430A US2019003713A1 US 20190003713 A1 US20190003713 A1 US 20190003713A1 US 201816132430 A US201816132430 A US 201816132430A US 2019003713 A1 US2019003713 A1 US 2019003713A1
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- Prior art keywords
- air
- fuel injection
- fuel
- assembly
- injection port
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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
- F23R3/286—Continuous combustion chambers using liquid or gaseous fuel characterised by the fuel supply having fuel-air premixing devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
- F02C7/22—Fuel supply systems
- F02C7/222—Fuel flow conduits, e.g. manifolds
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/46—Details, e.g. noise reduction means
- F23D14/62—Mixing devices; Mixing tubes
- F23D14/64—Mixing devices; Mixing tubes with injectors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2240/00—Components
- F05D2240/35—Combustors or associated equipment
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2240/00—Components
- F05D2240/35—Combustors or associated equipment
- F05D2240/36—Fuel vaporizer
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D2206/00—Burners for specific applications
- F23D2206/10—Turbines
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
- F23D2900/11002—Liquid fuel burners with more than one nozzle
Definitions
- the embodiments described herein relate generally to combustion systems, and more specifically, to systems that facilitate optimal mixing of liquid and gaseous fuels with oxidizer in a turbine combustor, such as gas turbine engine or liquid fuel aero-engine.
- Combustors are commonly used in industrial, power generation and aero operations to ignite fuel to produce combustion gases having a high temperature and pressure.
- turbo-machines such as gas turbine engines or aero-engines, may include one or more combustors to generate power or thrust.
- a typical turbine system includes an inlet section, a compressor section, a combustion section, a turbine section, and an exhaust section.
- the inlet section cleans and conditions a working fluid (e.g., air) and supplies the working fluid to the compressor section.
- the compressor section increases the pressure of the working fluid and supplies a compressed working fluid to the combustion section.
- the combustion section mixes fuel with the compressed working fluid and ignites the mixture to generate combustion gases having a high temperature and pressure.
- the combustion gases flow to the turbine section where they expand to produce work. For example, expansion of the combustion gases in the turbine section may rotate a shaft connected to a generator to produce electricity.
- the combustion section may include one or more combustors annularly arranged between the compressor section and the turbine section, and the temperature of the combustion gases directly influences the thermodynamic efficiency, design margins, and resulting emissions of the combustor.
- higher combustion temperatures generally improve the thermodynamic efficiency of the combustor.
- higher combustion temperatures also promote flame holding conditions in which the combustion flame migrates towards the fuel being supplied by nozzles, possibly causing accelerated damage to the nozzles in a relatively short amount of time.
- higher combustion temperatures generally increase the disassociation rate of diatomic nitrogen, increasing the production of nitrogen oxides (NO x ) for the same residence time in the combustor.
- a lower combustion temperature associated with reduced fuel flow and/or part load operation (turndown) generally reduces the chemical reaction rates of the combustion gases, increasing the production of carbon monoxide and unburned hydrocarbons for the same residence time in the combustor.
- the combustor may include a cap assembly that extends radially across at least a portion of the combustor, and one or more fuel nozzles may be radially arranged across the cap assembly to supply fuel to the combustor.
- the combustor may also include at least one annular liner that extends downstream from the cap assembly. The liner at least partially defines a combustion chamber within the combustor. The liner further defines a hot gas path that extends between the combustion chamber and an inlet to the turbine.
- the fuel nozzles may include swirler vanes and/or other flow guides to enhance mixing between the fuel and the compressed working fluid to produce a lean fuel-air mixture for combustion. The swirling fuel-air mixture flows into the combustion chamber where it ignites to generate the hot combustion gases. The hot combustion gases are routed through the hot gas path to the inlet of the turbine.
- the overall effectiveness of the engine is at least partially dependent upon how well the fuel-air combination that flows from the injector mixes with the swirling fuel-air mixture in the combustion chamber and/or with the hot combustion gases flowing through the liner generally downstream from the combustion chamber. For example, enhanced mixing of the fuel-air combination from the injector with the swirling fuel-air mixture in the combustion chamber and/or with the hot combustion gases flowing through the liner reduces peak flame temperature within the combustor, thereby reducing NO x levels.
- an air-shielded fuel injector assembly for use in a combustion chamber of a turbine engine.
- the air-shielded fuel injector assembly including a fuel manifold having a plurality of fuel injection ports and an air manifold having a plurality of air injection ports.
- Each fuel injection port is configured to introduce a fuel column into an annular cavity of a mixer assembly
- Each air injection port is configured to introduce an air curtain to minimize recirculation upstream of the fuel injection column and increase penetration of the fuel injection column into the cavity.
- a mixer assembly for use in a combustion chamber of a turbine engine assembly.
- the mixer assembly including a mixer having a main housing and defining an annular cavity, an air-shielded fuel injection assembly in fluid communication with the annular cavity and a swirler positioned upstream from the air-shielded fuel injection assembly.
- the air-shielded fuel injection assembly including a plurality of fuel injection ports and a plurality of air injection ports. Each fuel injection port is configured to introduce a fuel column into the annular cavity. Each air injection port is configured to introduce one of an upstream air curtain or a downstream air curtain relative to an associated fuel injection column.
- the swirler is positioned upstream from the air-shielded fuel injection assembly and includes a plurality of vanes for swirling air traveling through the swirler to mix air and the one of an upstream air curtain or a downstream air curtain and the associated fuel injection column.
- a turbine engine assembly including a compressor section, a combustor section and a turbine section configured in a downstream axial flow relationship.
- the combustor section including a combustion chamber and a mixer assembly disposed in the combustion chamber.
- the mixer assembly including a mixer having a main housing and defining an annular cavity, an air-shielded fuel injection assembly in fluid communication with the annular cavity and a swirler positioned upstream from the air-shielded fuel injection assembly.
- the air-shielded fuel injection assembly including a plurality of fuel injection ports and a plurality of air injection ports. Each fuel injection port is configured to introduce a fuel column into the annular cavity.
- Each air injection port is configured to introduce one of an upstream air curtain or a downstream air curtain relative to an associated fuel injection column introduced by an associated fuel injection port of the plurality of fuel injection ports.
- the swirler is positioned upstream from the air-shielded fuel injection assembly and includes a plurality of vanes for swirling air traveling through the wirier to mix air, and the air curtain and the associated fuel injection column dispensed by the plurality of fuel injection ports and the plurality of air injection ports.
- FIG. 1 is schematic diagram of an exemplary turbine engine assembly including a combustion section, according to one or more embodiments disclosed herein
- FIG. 2 is a simplified side cross-section view of a portion of an exemplary combustor, according to one or more embodiments disclosed herein;
- FIG. 3 is a simplified side cross-section view of a mixer assembly including an air-shielded fuel injection assembly, according to one or more embodiments disclosed herein;
- FIG. 4 is an enlarged simplified diagram illustrating the air-shielded fuel injection assembly of FIG. 3 , according to one or more embodiments disclosed herein;
- FIG. 5 provides a side diagrammatic view of the fuel injection flow pattern as a result of the air-shielded fuel injection assembly, according to one or more embodiments disclosed herein;
- FIG. 6 is a top schematic view illustrating alignment of an air injection port and an associated fuel injection port, according to one or more embodiments disclosed herein;
- FIG. 7 is a simplified side cross-section view of an alternate embodiment of a mixer assembly including an air-shielded fuel injection assembly, according to one or more embodiments disclosed herein;
- FIG. 8 is an enlarged simplified diagram illustrating the air-shielded fuel injection assembly of FIG. 7 , according to one or more embodiments disclosed herein.
- first end is used throughout this application to refer to directions and orientations located upstream in an overall axial flow direction of fluids with respect to a center longitudinal axis of a combustion chamber.
- axial and “axially” are used throughout this application to refer to directions and orientations extending substantially parallel to a center longitudinal axis of a combustion chamber.
- radial and “radially” are used throughout this application to refer to directions and orientations extending substantially perpendicular to a center longitudinal axis of the combustion chamber.
- upstream and downstream are used throughout this application to refer to directions and orientations located in an overall axial flow direction with respect to the center longitudinal axis of the combustion chamber.
- FIG. 1 provides a diagram of an exemplary turbine engine assembly 10 that may incorporate various embodiments of the present disclosure.
- the disclosed turbine engine assembly 10 e.g., a gas turbine engine, a liquid fueled aero-engine, etc.
- the disclosed turbine engine assembly 10 may employ one or more mixer assemblies (described presently), including one or more fuel nozzles (e.g., turbine fuel nozzles) with an improved design for fuel injection to enhance premixing of the fuel, and control over the fuel-air profile, while reducing emissions (e.g., NO x ) in the turbine engine assembly 10 .
- mixer assemblies described presently
- fuel nozzles e.g., turbine fuel nozzles
- NO x emissions
- FIG. 1 depicts in diagrammatic form an exemplary turbine engine assembly 10 (high bypass type engine) utilized with aircraft having a longitudinal or axial centerline axis 11 therethrough for reference purposes.
- Assembly 10 preferably includes a core turbine engine generally identified by numeral 12 and a fan section 14 positioned upstream thereof.
- Core engine 12 typically includes a generally tubular outer casing 16 that defines an annular inlet 18 .
- Outer casing 16 further encloses and supports a booster compressor 20 for raising the pressure of the air that enters core engine 12 to a first pressure level.
- a high pressure, multi-stage, axial-flow high pressure compressor 21 receives pressurized air from booster 20 and further increases the pressure of the air.
- the pressurized air flows to a combustor 22 , generally defined by a combustion liner 23 , and including a mixer assembly 24 , where fuel is injected into the pressurized air stream, via one or more fuel nozzles 25 to raise the temperature and energy level of the pressurized air.
- the high energy combustion products flow from combustor 22 to a first (high pressure) turbine 26 for driving high pressure compressor 21 through a first (high pressure) drive shaft 27 , and then to a second (low pressure) turbine 28 for driving booster compressor 20 and fan section 14 through a second (low pressure) drive shaft 29 that is coaxial with first drive shaft 27 .
- the combustion products leave core engine 12 through an exhaust nozzle 30 to provide propulsive jet thrust.
- Fan section 14 includes a rotatable, axial-flow fan rotor 32 that is surrounded by an annular fan casing 34 .
- fan casing 34 is supported from core engine 12 by a plurality of substantially radially-extending, circumferentially-spaced outlet guide vanes 36 . In this way, fan casing 34 encloses the fan rotor 32 and a plurality of fan rotor blades 38 .
- a downstream section 40 of fan casing 34 extends over an outer portion of core engine 12 to define a secondary, or bypass, airflow conduit 42 that provides additional propulsive jet thrust.
- Air flow 43 enters the turbine engine assembly 10 through an inlet 44 to fan casing 34 .
- Air flow 43 passes through fan blades 38 and splits into a first compressed air flow (represented by arrow 45 ) and a second compressed air flow (represented by arrow 46 ) which enters booster compressor 20 .
- the pressure of the second compressed air flow 46 is increased and enters high pressure compressor 21 , as represented by arrow 47 .
- combustion products 48 exit combustor 22 and flow through the first turbine 26 . Combustion products 48 then flow through the second turbine 28 and exit the exhaust nozzle 30 to provide thrust for the turbine engine assembly 10 .
- the one or more fuel nozzles in the mixer assembly 24 intake the fuel from a fuel supply (e.g., liquid and/or gas fuel), mix the fuel with air, and distribute the air-fuel mixture into the one or more combustor 22 in a suitable ratio for optimal combustion, emissions, fuel consumption, and power output.
- a fuel supply e.g., liquid and/or gas fuel
- the turbine engine assembly 10 includes the mixer assembly 24 including the one or more fuel nozzles 25 , including an air-shielded fuel injection assembly (described presently).
- the combustor 50 includes a combustion chamber 52 in which combustor air is mixed with fuel and burned.
- the combustor 50 includes an outer liner 54 and an inner liner 56 .
- the outer liner 54 defines an outer boundary of the combustion chamber 52
- the inner liner 56 defines an inner boundary of the combustion chamber 52 .
- An annular dome, generally designated by 58 mounted upstream from the outer liner 54 and the inner liner 56 defines an upstream end of the combustion chamber 52 .
- One or more mixer assemblies of the present invention, generally designated by 60 are positioned on the dome 58 .
- each of the mixer assemblies 60 includes a novel air-shielded fuel injection assembly (described presently) for delivery of a mixture of fuel and air to the combustion chamber 52 .
- a novel air-shielded fuel injection assembly (described presently) for delivery of a mixture of fuel and air to the combustion chamber 52 .
- Other features of the combustion chamber 52 are conventional and will not be discussed in further detail.
- each mixer assembly 60 generally comprises a pilot mixer, generally designated by 62 , and a main mixer, generally designated by 64 and including the air-shielded fuel injection assembly (described presently), surrounding the pilot mixer 62 .
- the pilot mixer 62 includes an annular pilot housing 66 having a hollow interior 68 .
- a pilot fuel nozzle, generally designated by 70 is mounted in the annular pilot housing 66 along a centerline 71 of the mixer assembly 60 .
- the pilot fuel nozzle 70 includes a fuel injector 72 adapted for dispensing droplets of fuel into the hollow interior 68 of the pilot housing 66 . It is envisioned that the fuel injector 72 may include an injector such as described in U.S. Pat. No. 5,435,884, which is hereby incorporated by reference.
- the pilot mixer 62 also includes a concentrically mounted axial swirler, generally designated by 80 , and having a plurality of vanes 84 , positioned upstream from the pilot fuel nozzle 70 .
- Each of the vanes 84 is skewed relative to the centerline 71 of the mixer 60 for swirling air traveling through the pilot swirler 80 so it mixes with the droplets of fuel dispensed by the pilot fuel nozzle 70 to form a fuel-air mixture selected for optimal burning during ignition and low power settings of the engine.
- the pilot mixer 62 of the disclosed embodiment has a single axial swirler 80 , those skilled in the art will appreciate that the pilot mixer 62 may include more swirlers without departing from the scope of the present disclosure.
- the swirlers may be configured having differing numbers of vanes as well as configured to swirl air in the same direction or in opposite directions.
- the pilot interior 68 may be sized and the pilot swirler 80 airflow and swirl angle may be selected to provide good ignition characteristics, lean stability and low CO and HC emissions at low power conditions.
- the housing 66 includes a generally diverging inner surface 74 adapted to provide controlled diffusion for mixing the pilot air with the main mixer airflow.
- the diffusion also reduces the axial velocities of air passing through the pilot mixer 62 and allows recirculation of hot gasses to stabilize the pilot flame.
- the main mixer 64 includes a main housing 90 surrounding the pilot housing 66 and defining an annular cavity 92 and an air-shielded fuel injection assembly 65 in fluid communication with the annular cavity 92 .
- the air-shielded fuel injection assembly 65 includes a fuel manifold 94 and an air manifold 95 mounted in a housing 96 between the pilot housing 6 and the main housing 90 .
- the fuel manifold 94 has a plurality of fuel injection ports 98 for introducing a fuel column 100 , comprised of droplets of fuel, into the cavity 92 of the main mixer 64 .
- the fuel manifold 94 may have any number of fuel injection ports 98 without departing from the scope of the present disclosure.
- the fuel manifold 94 has a single circumferential row consisting of 10 evenly spaced ports.
- the ports 98 are arranged in a single circumferential row in the embodiment shown in FIG. 3 , those skilled in the art will appreciate that they may be arranged in other configurations without departing from the scope of the present disclosure.
- the air manifold 95 includes a plurality of air injection ports 102 for introducing an air curtain 104 about each of the fuel injection columns 100 and into the cavity 92 of the main mixer 64 .
- each of the plurality of air injection ports 102 is associated with one of the plurality of fuel injection ports 98 and configured upstream of the associated fuel injection port 98 to form an upstream curtain of air thereabout the fuel column 100 introduced by the associated fuel injection port 98 .
- the term “curtain” is used to indicate at least a partial “wrapping” of the injected air about the injected fuel column or injection of air relative to the injected fuel column in a manner so as to steer the trajectory 101 of the injected fuel droplets.
- the formation of the upstream air curtain 104 about each of the fuel injection columns 100 minimizes recirculation upstream (behind) each of the fuel injection columns 100 and increases liquid jet penetration into the cavity 92 .
- the improved jet penetration provides reduction in fuel wall wetting near fuel injector ports 98 .
- the formation of the upstream air curtain 104 about each of the fuel injection columns 100 provides for a tunable assembly that includes the flexibility to adjust the degree of fuel-air mixing to achieve low NO x and complete combustion under variable conditions, resulting in lower emissions.
- the formation of the upstream air curtain 104 about each of the fuel injection columns 100 provides reduction in fuel residence time, resulting in lower likelihood of autoignition in the main mixer 64 .
- the mixers are physically separated.
- the distance between the pilot mixer 62 and the main mixer 64 may be selected to improve ignition characteristics, combustion stability at high and lower power and low CO and HC emissions at low power conditions.
- the main mixer 64 also includes a swirler 110 positioned upstream from the plurality of fuel injection ports 98 and the plurality of air injection ports 102 .
- the main swirler 110 may have other configurations without departing from the scope of the present disclosure, in one embodiment the main swirler is a radial swirler having a plurality of radially skewed vanes 112 for swirling air traveling through the swirler 110 to mix air passing through the swirler 110 and injected by the air injection ports 102 and the droplets of fuel dispensed by the fuel ports 98 in the annular housing 96 to form a fuel-air mixture selected for optimal burning during high power settings of the engine.
- the main wirier 110 may have a different number of vanes 112 without departing from the scope of the present disclosure, in one embodiment the main wirier has 40 vanes.
- the main mixer 64 is primarily designed to achieve low NO x under high power conditions by operating with a lean air-fuel mixture and by maximizing the fuel and air pre-mixing via the upstream air curtain 104 about the fuel injection column 100 .
- the radial wirier 110 of the main mixer 64 swirls the incoming air through the radial vanes 112 and establishes the basic flow field of the combustor 50 ( FIG. 2 ).
- fuel droplets are injected radially outward into the swirling air stream downstream from the main swirler 110 as fuel injection column 100 .
- the main swirler 110 in combination with the formation of the upstream air curtain 104 about the fuel injection column 100 allows for thorough mixing within the main mixer cavity 92 upstream from its exit. This swirling mixture enters the combustor chamber 52 ( FIG. 2 ) where it is burned completely.
- the upstream air curtain 104 of FIG. 3 as it relates to the fuel injection column 100 and the resulting air/fuel flows.
- the upstream air curtain 104 is injected via the air injection port 102 .
- the air injection port 102 has a general contoured configuration as shown in FIG. 4 .
- the contoured configuration has a general “kidney bean” shape.
- the air injection port 102 may have any custom shape that provides for the injection of an air jet that serves as a shield for the liquid fuel column, and more particularly the fuel injection column 100 .
- the shape and location of the air jet inlet, and more particularly the air injection port 102 , as well as the distance between the fuel injection port 98 and the air injection port 102 may be adjusted on a case-by-case basis, provided a center of the air injection port 102 is aligned with the center of an associated fuel injection port 98 (as described presently).
- an upstream swirl crossflow 120 Illustrated by directional arrow in FIGS. 3-5 , is an upstream swirl crossflow 120 .
- the presence of the upstream air curtain 104 about the fuel injection column 100 will increase the penetration of the liquid jet, and more particularly the fuel injection column 100 , into the upstream swirl crossflow 120 .
- a trajectory 101 of the fuel droplets in the fuel injection column 100 away from the fuel injection port 98 determine a flow angle “ ⁇ ” as best illustrated in FIG. 6 , which shows the view from the top looking down, with the upstream-to-downstream axial direction represented from bottom to top in FIG. 6 .
- the center of the air injection port 102 which in this particular embodiment is illustrated as rectangular in shape, and the center of the fuel injection port 98 are aligned along a vector 130 forming the flow angle “ ⁇ ”.
- the area of the air injection port 102 is designed based on expected pressure, drop near the air shield region, and more particularly, the upstream air curtain 104 , air density and desired amount of air flow through the shield region.
- a distance ⁇ between the center of the fuel injection port 98 and the air injection port 102 may be adjusted on a case-by-case basis.
- FIGS. 7 and 8 illustrated is an alternate embodiment of the air-shielded fuel injection assembly to facilitate reduced NO x emissions in a combustor system, generally designated 150 .
- the air manifold 95 includes a plurality of air injection ports 102 for introducing an air curtain 152 relative to each of the fuel injection columns 100 and into the cavity 92 of the main mixer 64 .
- FIGS. 7 and 8 illustrated is an alternate embodiment of the air-shielded fuel injection assembly to facilitate reduced NO x emissions in a combustor system, generally designated 150 .
- the air manifold 95 includes a plurality of air injection ports 102 for introducing an air curtain 152 relative to each of the fuel injection columns 100 and into the cavity 92 of the main mixer 64 .
- each of the plurality of air injection ports 102 is associated with one of the plurality of fuel injection ports 98 and configured downstream of the associated fuel injection port 98 to form a downstream curtain of air 152 relative to the fuel column 100 introduced via the associated fuel injection port 98 .
- the term “curtain” is used to indicate at least a partial “wrapping” of the injected air about the injected fuel column or injection of air relative to the injected fuel column in a manner so as to steer the trajectory of the injected fuel droplets.
- the disclosure provides an air-shielded fuel injection assembly to enhance the mixing of the fuel flowing from the fuel injector with air supplied via a swirler to the combustion chamber and thus reduces production of undesirable emissions such as oxides of nitrogen or NO x .
- the air-shielded fuel injection column provides for the reduction in the risk of autoignition that may lead to improved durability of the hardware, and thereby a reduction in the need for maintenance or replacement.
- Another benefit of the disclosure is that the fuel-to-air ratio or volume of fuel divided by the volume of air profile at the fuel injector exit can be controlled so that the NO x performance can be optimized.
- various embodiments of the present disclosure may allow extended combustor operating conditions, extend the life and/or maintenance intervals for various combustor components, maintain adequate design margins of flame holding, and/or reduce undesirable emissions.
- improved fuel-air mixing is also expected to yield better efficiency at a cruise condition.
- the proposed mixer assembly including the proposed injector design improves fuel/air mixing (compared to current fuel injector products), which consequently improves combustion efficiency, lowers NO x emissions and auto-ignition probabilities.
- the fuel injector provides wider operability, lower fuel pump pressure and increased durability.
- the fuel injector as disclosed herein requires less maintenance than known fuel injectors, results in a safer engine and weighs less than known fuel injectors, resulting in fuel cost savings.
- an air-shielded fuel injector Exemplary embodiments of an air-shielded fuel injector are described in detail above.
- the air-shielded fuel injectors are not limited to use with the specified turbine containing systems described herein, but rather, the air-shielded fuel injectors can be utilized independently and separately from other turbine containing system components described herein.
- the present disclosure is not limited to the embodiments of the air-shielded fuel injectors described in detail above. Rather, other variations of the air-shielded fuel injector embodiments may be utilized within the spirit and scope of the claims.
Abstract
Description
- The embodiments described herein relate generally to combustion systems, and more specifically, to systems that facilitate optimal mixing of liquid and gaseous fuels with oxidizer in a turbine combustor, such as gas turbine engine or liquid fuel aero-engine.
- Combustors are commonly used in industrial, power generation and aero operations to ignite fuel to produce combustion gases having a high temperature and pressure. For example, turbo-machines such as gas turbine engines or aero-engines, may include one or more combustors to generate power or thrust. A typical turbine system includes an inlet section, a compressor section, a combustion section, a turbine section, and an exhaust section. The inlet section cleans and conditions a working fluid (e.g., air) and supplies the working fluid to the compressor section. The compressor section increases the pressure of the working fluid and supplies a compressed working fluid to the combustion section. The combustion section mixes fuel with the compressed working fluid and ignites the mixture to generate combustion gases having a high temperature and pressure. The combustion gases flow to the turbine section where they expand to produce work. For example, expansion of the combustion gases in the turbine section may rotate a shaft connected to a generator to produce electricity.
- The combustion section may include one or more combustors annularly arranged between the compressor section and the turbine section, and the temperature of the combustion gases directly influences the thermodynamic efficiency, design margins, and resulting emissions of the combustor. For example, higher combustion temperatures generally improve the thermodynamic efficiency of the combustor. However, higher combustion temperatures also promote flame holding conditions in which the combustion flame migrates towards the fuel being supplied by nozzles, possibly causing accelerated damage to the nozzles in a relatively short amount of time. In addition, higher combustion temperatures generally increase the disassociation rate of diatomic nitrogen, increasing the production of nitrogen oxides (NOx) for the same residence time in the combustor. Conversely, a lower combustion temperature associated with reduced fuel flow and/or part load operation (turndown) generally reduces the chemical reaction rates of the combustion gases, increasing the production of carbon monoxide and unburned hydrocarbons for the same residence time in the combustor.
- In a particular combustor design, the combustor may include a cap assembly that extends radially across at least a portion of the combustor, and one or more fuel nozzles may be radially arranged across the cap assembly to supply fuel to the combustor. The combustor may also include at least one annular liner that extends downstream from the cap assembly. The liner at least partially defines a combustion chamber within the combustor. The liner further defines a hot gas path that extends between the combustion chamber and an inlet to the turbine. The fuel nozzles may include swirler vanes and/or other flow guides to enhance mixing between the fuel and the compressed working fluid to produce a lean fuel-air mixture for combustion. The swirling fuel-air mixture flows into the combustion chamber where it ignites to generate the hot combustion gases. The hot combustion gases are routed through the hot gas path to the inlet of the turbine.
- Although generally effective at enabling higher operating temperatures, the overall effectiveness of the engine is at least partially dependent upon how well the fuel-air combination that flows from the injector mixes with the swirling fuel-air mixture in the combustion chamber and/or with the hot combustion gases flowing through the liner generally downstream from the combustion chamber. For example, enhanced mixing of the fuel-air combination from the injector with the swirling fuel-air mixture in the combustion chamber and/or with the hot combustion gases flowing through the liner reduces peak flame temperature within the combustor, thereby reducing NOx levels.
- As a result, an improved system for supplying fuel to a combustor that enhances mixing of the fuel-air combination that flows from the fuel injectors would be useful.
- Aspects and advantages of the disclosure are set forth below in the following description, or may be obvious from the description, or may be learned through practice of the disclosure.
- In one aspect, an air-shielded fuel injector assembly for use in a combustion chamber of a turbine engine is provided. The air-shielded fuel injector assembly including a fuel manifold having a plurality of fuel injection ports and an air manifold having a plurality of air injection ports. Each fuel injection port is configured to introduce a fuel column into an annular cavity of a mixer assembly Each air injection port is configured to introduce an air curtain to minimize recirculation upstream of the fuel injection column and increase penetration of the fuel injection column into the cavity.
- In another aspect, a mixer assembly for use in a combustion chamber of a turbine engine assembly is provided. The mixer assembly including a mixer having a main housing and defining an annular cavity, an air-shielded fuel injection assembly in fluid communication with the annular cavity and a swirler positioned upstream from the air-shielded fuel injection assembly. The air-shielded fuel injection assembly including a plurality of fuel injection ports and a plurality of air injection ports. Each fuel injection port is configured to introduce a fuel column into the annular cavity. Each air injection port is configured to introduce one of an upstream air curtain or a downstream air curtain relative to an associated fuel injection column. The swirler is positioned upstream from the air-shielded fuel injection assembly and includes a plurality of vanes for swirling air traveling through the swirler to mix air and the one of an upstream air curtain or a downstream air curtain and the associated fuel injection column.
- In yet another aspect, a turbine engine assembly is provided. The turbine engine assembly including a compressor section, a combustor section and a turbine section configured in a downstream axial flow relationship. The combustor section including a combustion chamber and a mixer assembly disposed in the combustion chamber. The mixer assembly including a mixer having a main housing and defining an annular cavity, an air-shielded fuel injection assembly in fluid communication with the annular cavity and a swirler positioned upstream from the air-shielded fuel injection assembly. The air-shielded fuel injection assembly including a plurality of fuel injection ports and a plurality of air injection ports. Each fuel injection port is configured to introduce a fuel column into the annular cavity. Each air injection port is configured to introduce one of an upstream air curtain or a downstream air curtain relative to an associated fuel injection column introduced by an associated fuel injection port of the plurality of fuel injection ports. The swirler is positioned upstream from the air-shielded fuel injection assembly and includes a plurality of vanes for swirling air traveling through the wirier to mix air, and the air curtain and the associated fuel injection column dispensed by the plurality of fuel injection ports and the plurality of air injection ports.
- A full and enabling disclosure of the present disclosure, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:
-
FIG. 1 is schematic diagram of an exemplary turbine engine assembly including a combustion section, according to one or more embodiments disclosed herein -
FIG. 2 is a simplified side cross-section view of a portion of an exemplary combustor, according to one or more embodiments disclosed herein; -
FIG. 3 is a simplified side cross-section view of a mixer assembly including an air-shielded fuel injection assembly, according to one or more embodiments disclosed herein; -
FIG. 4 is an enlarged simplified diagram illustrating the air-shielded fuel injection assembly ofFIG. 3 , according to one or more embodiments disclosed herein; -
FIG. 5 provides a side diagrammatic view of the fuel injection flow pattern as a result of the air-shielded fuel injection assembly, according to one or more embodiments disclosed herein; -
FIG. 6 is a top schematic view illustrating alignment of an air injection port and an associated fuel injection port, according to one or more embodiments disclosed herein; -
FIG. 7 is a simplified side cross-section view of an alternate embodiment of a mixer assembly including an air-shielded fuel injection assembly, according to one or more embodiments disclosed herein; and -
FIG. 8 is an enlarged simplified diagram illustrating the air-shielded fuel injection assembly ofFIG. 7 , according to one or more embodiments disclosed herein. - Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.
- The exemplary methods and systems described herein overcome the structural disadvantages of known fuel injectors by providing optimal mixing of liquid and gaseous fuels with oxidizer in the combustor. It should also be appreciated that the term “first end” is used throughout this application to refer to directions and orientations located upstream in an overall axial flow direction of fluids with respect to a center longitudinal axis of a combustion chamber. It should be appreciated that the terms “axial” and “axially” are used throughout this application to refer to directions and orientations extending substantially parallel to a center longitudinal axis of a combustion chamber. It should also be appreciated that the terms “radial” and “radially” are used throughout this application to refer to directions and orientations extending substantially perpendicular to a center longitudinal axis of the combustion chamber. It should also be appreciated that the terms “upstream” and “downstream” are used throughout this application to refer to directions and orientations located in an overall axial flow direction with respect to the center longitudinal axis of the combustion chamber.
- Each example is provided by way of explanation of the disclosure, not limitation of the disclosure. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present disclosure 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 disclosure covers such modifications and variations as come within the scope of the appended claims and their equivalents. Although exemplary embodiments of the present disclosure will be described generally in the context of a fuel injector assembly for 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 disclosure may be applied to any combustor assembly incorporated into any turbomachine, and not limited to gas turbine engines.
- Referring now to the drawings, wherein identical numerals indicate the same elements throughout the figures,
FIG. 1 provides a diagram of an exemplaryturbine engine assembly 10 that may incorporate various embodiments of the present disclosure. As described in detail below, the disclosed turbine engine assembly 10 (e.g., a gas turbine engine, a liquid fueled aero-engine, etc.) may employ one or more mixer assemblies (described presently), including one or more fuel nozzles (e.g., turbine fuel nozzles) with an improved design for fuel injection to enhance premixing of the fuel, and control over the fuel-air profile, while reducing emissions (e.g., NOx) in theturbine engine assembly 10. -
FIG. 1 depicts in diagrammatic form an exemplary turbine engine assembly 10 (high bypass type engine) utilized with aircraft having a longitudinal oraxial centerline axis 11 therethrough for reference purposes.Assembly 10 preferably includes a core turbine engine generally identified bynumeral 12 and afan section 14 positioned upstream thereof.Core engine 12 typically includes a generally tubularouter casing 16 that defines anannular inlet 18.Outer casing 16 further encloses and supports abooster compressor 20 for raising the pressure of the air that enterscore engine 12 to a first pressure level. A high pressure, multi-stage, axial-flowhigh pressure compressor 21 receives pressurized air frombooster 20 and further increases the pressure of the air. The pressurized air flows to acombustor 22, generally defined by acombustion liner 23, and including a mixer assembly 24, where fuel is injected into the pressurized air stream, via one or more fuel nozzles 25 to raise the temperature and energy level of the pressurized air. The high energy combustion products flow fromcombustor 22 to a first (high pressure)turbine 26 for drivinghigh pressure compressor 21 through a first (high pressure) driveshaft 27, and then to a second (low pressure)turbine 28 for drivingbooster compressor 20 andfan section 14 through a second (low pressure) driveshaft 29 that is coaxial withfirst drive shaft 27. After driving each ofturbines core engine 12 through anexhaust nozzle 30 to provide propulsive jet thrust. -
Fan section 14 includes a rotatable, axial-flow fan rotor 32 that is surrounded by anannular fan casing 34. It will be appreciated thatfan casing 34 is supported fromcore engine 12 by a plurality of substantially radially-extending, circumferentially-spaced outlet guide vanes 36. In this way,fan casing 34 encloses thefan rotor 32 and a plurality offan rotor blades 38. Adownstream section 40 offan casing 34 extends over an outer portion ofcore engine 12 to define a secondary, or bypass,airflow conduit 42 that provides additional propulsive jet thrust. - From a flow standpoint, it will be appreciated that an initial air flow, represented by
arrow 43, enters theturbine engine assembly 10 through aninlet 44 tofan casing 34. Air flow 43 passes throughfan blades 38 and splits into a first compressed air flow (represented by arrow 45) and a second compressed air flow (represented by arrow 46) which entersbooster compressor 20. The pressure of the secondcompressed air flow 46 is increased and entershigh pressure compressor 21, as represented byarrow 47. After mixing with fuel and being combusted incombustor 22combustion products 48exit combustor 22 and flow through thefirst turbine 26.Combustion products 48 then flow through thesecond turbine 28 and exit theexhaust nozzle 30 to provide thrust for theturbine engine assembly 10. - During operation, the one or more fuel nozzles in the mixer assembly 24, intake the fuel from a fuel supply (e.g., liquid and/or gas fuel), mix the fuel with air, and distribute the air-fuel mixture into the one or
more combustor 22 in a suitable ratio for optimal combustion, emissions, fuel consumption, and power output. Theturbine engine assembly 10 includes the mixer assembly 24 including the one or more fuel nozzles 25, including an air-shielded fuel injection assembly (described presently). - Referring to the drawings and in particular to
FIG. 2 , illustrated is anexemplary combustor 50, generally similar tocombustors 22 ofFIG. 1 . Thecombustor 50 includes acombustion chamber 52 in which combustor air is mixed with fuel and burned. Thecombustor 50 includes anouter liner 54 and aninner liner 56. Theouter liner 54 defines an outer boundary of thecombustion chamber 52, and theinner liner 56 defines an inner boundary of thecombustion chamber 52. An annular dome, generally designated by 58, mounted upstream from theouter liner 54 and theinner liner 56 defines an upstream end of thecombustion chamber 52. One or more mixer assemblies of the present invention, generally designated by 60, are positioned on thedome 58. According to this disclosure, each of themixer assemblies 60 includes a novel air-shielded fuel injection assembly (described presently) for delivery of a mixture of fuel and air to thecombustion chamber 52. Other features of thecombustion chamber 52 are conventional and will not be discussed in further detail. - Illustrated in
FIG. 3 is a first embodiment of air-shielded fuel injection assembly according to the disclosure. As illustrated, eachmixer assembly 60 generally comprises a pilot mixer, generally designated by 62, and a main mixer, generally designated by 64 and including the air-shielded fuel injection assembly (described presently), surrounding thepilot mixer 62. Thepilot mixer 62 includes anannular pilot housing 66 having ahollow interior 68. A pilot fuel nozzle, generally designated by 70, is mounted in theannular pilot housing 66 along acenterline 71 of themixer assembly 60. Thepilot fuel nozzle 70 includes afuel injector 72 adapted for dispensing droplets of fuel into thehollow interior 68 of thepilot housing 66. It is envisioned that thefuel injector 72 may include an injector such as described in U.S. Pat. No. 5,435,884, which is hereby incorporated by reference. - In the illustrated embodiment, the
pilot mixer 62 also includes a concentrically mounted axial swirler, generally designated by 80, and having a plurality ofvanes 84, positioned upstream from thepilot fuel nozzle 70. Each of thevanes 84 is skewed relative to thecenterline 71 of themixer 60 for swirling air traveling through thepilot swirler 80 so it mixes with the droplets of fuel dispensed by thepilot fuel nozzle 70 to form a fuel-air mixture selected for optimal burning during ignition and low power settings of the engine. Although thepilot mixer 62 of the disclosed embodiment has a singleaxial swirler 80, those skilled in the art will appreciate that thepilot mixer 62 may include more swirlers without departing from the scope of the present disclosure. As will further be appreciated by those skilled in the art, when more than one swirler is included in the pilot mixer, the swirlers may be configured having differing numbers of vanes as well as configured to swirl air in the same direction or in opposite directions. Further, thepilot interior 68 may be sized and thepilot swirler 80 airflow and swirl angle may be selected to provide good ignition characteristics, lean stability and low CO and HC emissions at low power conditions. - The
housing 66 includes a generally diverginginner surface 74 adapted to provide controlled diffusion for mixing the pilot air with the main mixer airflow. The diffusion also reduces the axial velocities of air passing through thepilot mixer 62 and allows recirculation of hot gasses to stabilize the pilot flame. - The
main mixer 64 includes amain housing 90 surrounding thepilot housing 66 and defining anannular cavity 92 and an air-shieldedfuel injection assembly 65 in fluid communication with theannular cavity 92. The air-shieldedfuel injection assembly 65 includes afuel manifold 94 and anair manifold 95 mounted in ahousing 96 between the pilot housing 6 and themain housing 90. Thefuel manifold 94 has a plurality offuel injection ports 98 for introducing afuel column 100, comprised of droplets of fuel, into thecavity 92 of themain mixer 64. Thefuel manifold 94 may have any number offuel injection ports 98 without departing from the scope of the present disclosure. In one embodiment thefuel manifold 94 has a single circumferential row consisting of 10 evenly spaced ports. Although theports 98 are arranged in a single circumferential row in the embodiment shown inFIG. 3 , those skilled in the art will appreciate that they may be arranged in other configurations without departing from the scope of the present disclosure. - The
air manifold 95 includes a plurality ofair injection ports 102 for introducing anair curtain 104 about each of thefuel injection columns 100 and into thecavity 92 of themain mixer 64. In this particular embodiment, each of the plurality ofair injection ports 102 is associated with one of the plurality offuel injection ports 98 and configured upstream of the associatedfuel injection port 98 to form an upstream curtain of air thereabout thefuel column 100 introduced by the associatedfuel injection port 98. As used herein, the term “curtain” is used to indicate at least a partial “wrapping” of the injected air about the injected fuel column or injection of air relative to the injected fuel column in a manner so as to steer thetrajectory 101 of the injected fuel droplets. As will be understood by those skilled in the art, usingfuel injection ports 98 andair injection ports 102 at different axial locations along themain mixer cavity 92 so as to provide for the formation of theupstream air curtain 104 about each of thefuel injection columns 100 minimizes recirculation upstream (behind) each of thefuel injection columns 100 and increases liquid jet penetration into thecavity 92. The improved jet penetration provides reduction in fuel wall wetting nearfuel injector ports 98. In addition, the formation of theupstream air curtain 104 about each of thefuel injection columns 100 provides for a tunable assembly that includes the flexibility to adjust the degree of fuel-air mixing to achieve low NOx and complete combustion under variable conditions, resulting in lower emissions. In addition, the formation of theupstream air curtain 104 about each of thefuel injection columns 100 provides reduction in fuel residence time, resulting in lower likelihood of autoignition in themain mixer 64. - In an embodiment, by positioning the
annular housing 96 of thefuel manifold 94 and theair manifold 95 between thepilot mixer 62 and themain mixer 64, the mixers are physically separated. As will also be appreciated by those skilled in the art, the distance between thepilot mixer 62 and themain mixer 64 may be selected to improve ignition characteristics, combustion stability at high and lower power and low CO and HC emissions at low power conditions. - The
main mixer 64 also includes aswirler 110 positioned upstream from the plurality offuel injection ports 98 and the plurality ofair injection ports 102. Although themain swirler 110 may have other configurations without departing from the scope of the present disclosure, in one embodiment the main swirler is a radial swirler having a plurality of radially skewedvanes 112 for swirling air traveling through theswirler 110 to mix air passing through theswirler 110 and injected by theair injection ports 102 and the droplets of fuel dispensed by thefuel ports 98 in theannular housing 96 to form a fuel-air mixture selected for optimal burning during high power settings of the engine. Although theswirler 110 may have a different number ofvanes 112 without departing from the scope of the present disclosure, in one embodiment the main wirier has 40 vanes. Themain mixer 64 is primarily designed to achieve low NOx under high power conditions by operating with a lean air-fuel mixture and by maximizing the fuel and air pre-mixing via theupstream air curtain 104 about thefuel injection column 100. The radial wirier 110 of themain mixer 64 swirls the incoming air through theradial vanes 112 and establishes the basic flow field of the combustor 50 (FIG. 2 ). During operation, fuel droplets are injected radially outward into the swirling air stream downstream from themain swirler 110 asfuel injection column 100. Themain swirler 110 in combination with the formation of theupstream air curtain 104 about thefuel injection column 100 allows for thorough mixing within themain mixer cavity 92 upstream from its exit. This swirling mixture enters the combustor chamber 52 (FIG. 2 ) where it is burned completely. - Referring now to
FIGS. 4 and 5 , illustrated in schematic illustrations, is theupstream air curtain 104 ofFIG. 3 as it relates to thefuel injection column 100 and the resulting air/fuel flows. As illustrated, theupstream air curtain 104 is injected via theair injection port 102. In this particular embodiment, theair injection port 102 has a general contoured configuration as shown inFIG. 4 . In an embodiment, the contoured configuration has a general “kidney bean” shape. In an alternate embodiment, theair injection port 102 may have any custom shape that provides for the injection of an air jet that serves as a shield for the liquid fuel column, and more particularly thefuel injection column 100. The shape and location of the air jet inlet, and more particularly theair injection port 102, as well as the distance between thefuel injection port 98 and theair injection port 102 may be adjusted on a case-by-case basis, provided a center of theair injection port 102 is aligned with the center of an associated fuel injection port 98 (as described presently). - Illustrated by directional arrow in
FIGS. 3-5 , is anupstream swirl crossflow 120. The presence of theupstream air curtain 104 about thefuel injection column 100 will increase the penetration of the liquid jet, and more particularly thefuel injection column 100, into theupstream swirl crossflow 120. Atrajectory 101 of the fuel droplets in thefuel injection column 100 away from thefuel injection port 98 determine a flow angle “α” as best illustrated inFIG. 6 , which shows the view from the top looking down, with the upstream-to-downstream axial direction represented from bottom to top inFIG. 6 . The center of theair injection port 102, which in this particular embodiment is illustrated as rectangular in shape, and the center of thefuel injection port 98 are aligned along avector 130 forming the flow angle “α”. The area of theair injection port 102 is designed based on expected pressure, drop near the air shield region, and more particularly, theupstream air curtain 104, air density and desired amount of air flow through the shield region. A distance λ between the center of thefuel injection port 98 and theair injection port 102 may be adjusted on a case-by-case basis. - Referring now to
FIGS. 7 and 8 , illustrated is an alternate embodiment of the air-shielded fuel injection assembly to facilitate reduced NOx emissions in a combustor system, generally designated 150. Elements similar to those previously illustrated and described with regard to the first embodiment illustrated inFIGS. 3-6 are designated with identical numerals and are not further described. In the illustrated embodiment ofFIGS. 7 and 8 , theair manifold 95 includes a plurality ofair injection ports 102 for introducing anair curtain 152 relative to each of thefuel injection columns 100 and into thecavity 92 of themain mixer 64. In contrast to the embodiment ofFIGS. 3-6 , in this particular embodiment, each of the plurality ofair injection ports 102 is associated with one of the plurality offuel injection ports 98 and configured downstream of the associatedfuel injection port 98 to form a downstream curtain ofair 152 relative to thefuel column 100 introduced via the associatedfuel injection port 98. As previously indicated, the term “curtain” is used to indicate at least a partial “wrapping” of the injected air about the injected fuel column or injection of air relative to the injected fuel column in a manner so as to steer the trajectory of the injected fuel droplets. As will be understood by those skilled in the art, usingfuel injection ports 98 andair injection ports 102 at different axial locations along themain mixer cavity 92 so as to provide for the formation of thedownstream air curtain 152 relative to each of thefuel injection columns 100 enables the injected fuel to be kept away from a boundary layer, accelerates the flow of the injectedfuel column 100, makes the fuel/air mixture lean and enables reduction in fuel accumulation along a center body of the downstream assembly. - As emissions regulations tighten, hardware known for lower emissions will become increasingly important. Research has shown that in large mixers, fuel jet penetration had a first order impact on NOx emissions. The benefit from increasing mixer effective area to allow in more air flow to reduce NOx depends on whether penetration was sufficient. By shaping and sizing the
air injection port 102 so as to steer a trajectory of thefuel injection column 100 upward and/or in an axial downstream direction, as previously disclosed, improved mixing may be achieved. In addition, fuel drool and wetting (i.e., preventing liquid fuel droplets from landing on a metal center body) may be reduced, that in conjunction with a reduction in residence time, results in a reduction in fuel autoignition and/or flashback and subsequent flame holding in the boundary layer. - Accordingly, as disclosed herein and as illustrated in
FIGS. 1 -S provided are various technological advantages and/or improvements over existing mixer assemblies and fuel injection. The disclosure provides an air-shielded fuel injection assembly to enhance the mixing of the fuel flowing from the fuel injector with air supplied via a swirler to the combustion chamber and thus reduces production of undesirable emissions such as oxides of nitrogen or NOx. In addition, the air-shielded fuel injection column provides for the reduction in the risk of autoignition that may lead to improved durability of the hardware, and thereby a reduction in the need for maintenance or replacement. Another benefit of the disclosure is that the fuel-to-air ratio or volume of fuel divided by the volume of air profile at the fuel injector exit can be controlled so that the NOx performance can be optimized. As a result of the above, various embodiments of the present disclosure may allow extended combustor operating conditions, extend the life and/or maintenance intervals for various combustor components, maintain adequate design margins of flame holding, and/or reduce undesirable emissions. In addition, improved fuel-air mixing is also expected to yield better efficiency at a cruise condition. - This written description uses examples to disclose the disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
- The proposed mixer assembly including the proposed injector design improves fuel/air mixing (compared to current fuel injector products), which consequently improves combustion efficiency, lowers NOx emissions and auto-ignition probabilities. In addition, in an embodiment the fuel injector provides wider operability, lower fuel pump pressure and increased durability. Advantageously, the fuel injector as disclosed herein requires less maintenance than known fuel injectors, results in a safer engine and weighs less than known fuel injectors, resulting in fuel cost savings.
- Exemplary embodiments of an air-shielded fuel injector are described in detail above. The air-shielded fuel injectors are not limited to use with the specified turbine containing systems described herein, but rather, the air-shielded fuel injectors can be utilized independently and separately from other turbine containing system components described herein. Moreover, the present disclosure is not limited to the embodiments of the air-shielded fuel injectors described in detail above. Rather, other variations of the air-shielded fuel injector embodiments may be utilized within the spirit and scope of the claims.
- While the disclosure has been described in terms of various specific embodiments, those skilled in the art will recognize that the disclosure can be practiced with modification within the spirit and scope of the claims.
Claims (16)
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US16/132,430 US20190003713A1 (en) | 2014-08-15 | 2018-09-16 | Air-shielded fuel injection assembly to facilitate reduced nox emissions in a combustor system |
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US14/461,069 US10288291B2 (en) | 2014-08-15 | 2014-08-15 | Air-shielded fuel injection assembly to facilitate reduced NOx emissions in a combustor system |
US16/132,430 US20190003713A1 (en) | 2014-08-15 | 2018-09-16 | Air-shielded fuel injection assembly to facilitate reduced nox emissions in a combustor system |
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US14/461,069 Division US10288291B2 (en) | 2014-08-15 | 2014-08-15 | Air-shielded fuel injection assembly to facilitate reduced NOx emissions in a combustor system |
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US14/461,069 Active 2037-08-08 US10288291B2 (en) | 2014-08-15 | 2014-08-15 | Air-shielded fuel injection assembly to facilitate reduced NOx emissions in a combustor system |
US16/132,430 Abandoned US20190003713A1 (en) | 2014-08-15 | 2018-09-16 | Air-shielded fuel injection assembly to facilitate reduced nox emissions in a combustor system |
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FR3082284B1 (en) * | 2018-06-07 | 2020-12-11 | Safran Aircraft Engines | COMBUSTION CHAMBER FOR A TURBOMACHINE |
CN110657452B (en) * | 2018-06-29 | 2020-10-27 | 中国航发商用航空发动机有限责任公司 | Low-pollution combustion chamber and combustion control method thereof |
CN109737452B (en) * | 2019-01-23 | 2021-07-30 | 南方科技大学 | Center grading low-pollution combustion chamber suitable for gaseous fuel |
CN113531584B (en) * | 2020-04-15 | 2023-05-23 | 上海慕帆动力科技有限公司 | Combustion device of gas turbine |
KR102322596B1 (en) * | 2020-07-17 | 2021-11-05 | 두산중공업 주식회사 | Nozzle assembly for combustor and gas turbine combustor including the same |
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US10288291B2 (en) | 2019-05-14 |
US20160363319A1 (en) | 2016-12-15 |
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