Classifications

• • 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
• • 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
  • F23D14/48—Nozzles
  • F23D14/58—Nozzles characterised by the shape or arrangement of the outlet or outlets from the nozzle, e.g. of annular configuration
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2206/00—Burners for specific applications
  • F23D2206/10—Turbines

Definitions

• Disclosed embodiments are generally related to a fuel nozzle for use in a combustion turbine engine, such as a gas turbine engine and, more particularly, to a pre-mixing type of fuel nozzle that in one non-limiting application may be used in a distributed combustion system (DCS) injection system.
• DCS distributed combustion system
• fuel is delivered from a fuel source to a combustion section where the fuel is mixed with air and ignited to generate hot combustion products defining working gases.
• the working gases are directed to a turbine section.
• the combustion section may comprise one or more stages, each stage supplying fuel to be ignited. See US patent Nos. 8,281594 and 8,752,386 in connection with fuel nozzles involving pre-mixing of air and fuel.
• FIG. 1 is an isometric view that may be helpful for visualizing an upstream end of one non-limiting embodiment of a fuel nozzle embodying aspects of the invention that may be used in a combustor of a combustion turbine engine.
• FIG. 2 is a top view of the upstream end of the fuel nozzle shown in FIG. 1.
• FIG. 3 is a bottom view of a downstream end of the fuel nozzle shown in FIG. 1.
• FIG. 4 is a cross-sectional view illustrating a non-limiting schematic representation of respective pre-mixing conduits and air flow conduits constructed in the body of the fuel nozzle.
• FIG. 5 is a cross-sectional view illustrating a non-limiting schematic representation of fuel flow in a fuel-directing structure constructed in the body of the fuel nozzle.
• FIG. 6 is a top view illustrating a non-limiting schematic representation of fuel- injecting locations in a given pre-mixing conduit.
• FIG. 7 is a simplified schematic of one non- limiting embodiment of a combustion turbine engine, such as a gas turbine engine, that can benefit from disclosed embodiments of the present invention.
• the inventors of the present invention have recognized certain issues that can arise in the context of certain prior art fuel nozzles involving pre-mixing of air and fuel, also referred in the art as micro-mixing. These prior art fuel nozzles generally involve a large number of point injection arrays having a relatively small diameter, and the fabrication of such injection arrays may involve costly fabrication techniques. In view of such a recognition, the present inventors propose an improved fuel nozzle that can benefit from more economical fabrication techniques while providing appropriate levels of NO x emissions and enabling practically a flashback- free operation, even on applications involving a relatively high-content of hydrogen fuel.
• FIG. 1 is an isometric view of one non- limiting embodiment of a fuel nozzle 10 embodying aspects of the invention that in one non-limiting application may be used in a combustor of a combustion turbine engine, such as a gas turbine engine.
• Fuel nozzle 10 includes a body 12 having an inlet end 14 and an outlet end 16 and defines a central axis 18 that extends between inlet end 14 and outlet end 16 along an axial direction of the fuel nozzle.
• an array of pre-mixing conduits 20 extends between inlet end 14 and outlet end 16 of body 12.
• the array of pre-mixing conduits 20 is circumferentially disposed about central axis 18.
• Each pre-mixing conduit 20 is fluidly coupled to receive air at a respective inlet.
• fuel nozzle 10 further includes an array of air flow conduits 22 disposed radially inwardly relative to the array of pre-mixing conduits 20.
• fuel nozzle 10 may include means to aerodynamically reduce flow recirculation (flow separation) in the array of pre- mixing conduits 20.
• the means to aerodynamically reduce the flow recirculation in a respective pre-mixing conduit 20 may comprise an inter-conduit passageway 24 arranged to provide fluid communication between the respective pre-mixing conduit 20 and a corresponding air flow conduit 22. It will be appreciated that the geometry of pre-mixing conduits 20 may be optionally configured to reduce flow recirculation in combination or in lieu of inter-conduit passageways 24.
• fuel nozzle 10 further includes a fuel- directing structure 26 that in one-non-limiting embodiment includes a plurality of non-swirl elements 28.
• Each non-swirl element includes a radially-extending passageway to direct fuel flow along a radial direction (schematically represented by arrows 30).
• Each non-swirl element 28 includes at least one orifice 32 arranged to inject the fuel that flows along the radial direction into a respective air/ fuel pre- mixing conduit.
• orifices 32 may be located in regions of relatively high axial flow velocity, thus increasing the static pressure drop across orifices 32. See FIG. 6 that illustrates a non-limiting example of fuel-injecting locations
• Fuel- directing structure 26 further includes a central passageway 36 (FIG. 5) arranged to direct fuel flow along the axial direction (schematically represented by arrows 38) towards a central outlet 39.
• the array of pre-mixing conduits 20 each comprises at least a respective pre-mixing conduit segment (schematically represented by line 40 (FIG. 4)) having a cross-sectional area that increases as the respective pre- mixing conduit segment extends from a location between inlet end 14 and outlet end 16 towards a respective outlet 41 of the respective pre-mixing conduit.
• line 40 FIG. 4
• pre-mixing conduit segment 40 includes at least one surface 42 tilted radially inwardly relative to central axis 18 as the segment extends towards the respective outlet 41 of the respective pre-mixing conduit 20.
• the array of air flow conduits 22 each comprises at least a respective air flow conduit segment (schematically represented by line 44 (FIG. 4) having a cross-sectional area that decreases as the respective air flow conduit segment 44 extends from a respective inlet 45 of the respective air flow conduit 22 towards a location between inlet end 14 and outlet end 16.
• the array of air flow conduits 22 each comprises an outlet 46 arranged radially inwardly relative to central axis 18.
• central outlet 39 of central passageway 36 in combination with the respective outlets 46 of the array of air flow conduits 22 forms a jet-assisted mixing stage.
• FIG. 7 is a simplified schematic of one non- limiting embodiment of a combustion turbine engine 50, such as gas turbine engine, that can benefit from disclosed embodiments of the present invention.
• Combustion turbine engine 50 may comprise a compressor 52, a combustor 54, a combustion chamber 56, and a turbine 58.
• compressor 52 takes in ambient air and provides compressed air to a diffuser 60, which passes the compressed air to a plenum 62 through which the compressed air passes to combustor 54, which mixes the compressed air with fuel, and provides combusted, hot working gas via a transition 64 to turbine 58, which can drive power-generating equipment (not shown) to generate electricity.
• a shaft 66 is shown connecting turbine 58 to drive compressor 52.
• Disclosed embodiments of a fuel nozzle embodying aspects of the present invention may be incorporated in combustor 54 of the combustion turbine engine to achieve superior pre-mixing of fuel and air.
• disclosed embodiments are expected to provide a cost-effective fuel nozzle including arrays of fluid flow conduits that produce a substantially homogenous mixture of fuel and air at the outlet end of the nozzle and thus effective to produce appropriate pre-mixing of fuel and air conducive to ultra-low levels of NO x emissions. Additionally, disclosed embodiments need not involve swirler elements, and thus flashback resistance is substantially high, even for fuel blends comprising a high hydrogen content (e.g., at least 50% hydrogen content by volume).
• a high hydrogen content e.g., at least 50% hydrogen content by volume
• practical embodiments of the disclosed fuel nozzle may comprise fluid flow conduits having a minimum diameter in a range from about 0.75 mm to about 1 mm and thus capable of benefitting from relatively low-cost manufacturing technologies, such as, without limitation, three-dimensional (3D) printing, direct metal laser sintering (DLMS), etc., in lieu of presently costlier manufacturing technologies.
• relatively low-cost manufacturing technologies such as, without limitation, three-dimensional (3D) printing, direct metal laser sintering (DLMS), etc.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Spray-Type Burners (AREA)

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Publications (1)

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• 2015
  • 2015-04-01 WO PCT/US2015/023849 patent/WO2016160010A1/en active Application Filing
  • 2015-04-01 EP EP15717727.0A patent/EP3278030A1/de not_active Withdrawn
  • 2015-04-01 US US15/555,188 patent/US20180051883A1/en not_active Abandoned

Non-Patent Citations (2)

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