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
  • F23R3/02—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
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
  • F23C7/00—Combustion apparatus characterised by arrangements for air supply
  • F23C7/002—Combustion apparatus characterised by arrangements for air supply the air being submitted to a rotary or spinning motion
  • F23C7/004—Combustion apparatus characterised by arrangements for air supply the air being submitted to a rotary or spinning motion using vanes
• • 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
  • F23D11/36—Details
  • F23D11/38—Nozzles; Cleaning devices therefor
  • F23D11/383—Nozzles; Cleaning devices therefor with swirl means
• • 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
  • F23R3/34—Feeding into different combustion zones
  • F23R3/343—Pilot flames, i.e. fuel nozzles or injectors using only a very small proportion of the total fuel to insure continuous combustion
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
  • F23C2900/00—Special features of, or arrangements for combustion apparatus using fluid fuels or solid fuels suspended in air; Combustion processes therefor
  • F23C2900/07001—Air swirling vanes incorporating fuel injectors
• • 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
  • F23D2900/14—Special features of gas burners
  • F23D2900/14021—Premixing burners with swirling or vortices creating means for fuel or air

Definitions

• the invention relates to a fuel distributor, in particular for a burner and a swirler.
• the main purpose of the burner is to mix fuel and air together to obtain stable and efficient combustion with good flame stability and the smallest possible amount of NOx emissions. Therefore, the burner design must ensure that the proper amounts of fuel and air are introduced in the right locations within the burner and that these amounts of fuel and air are thoroughly mixed, so that complete combustion takes place with a minimum amount of excess air in order to achieve optimum overall efficiency.
• the two burner principles which could be combined to use their respective advantages, are the premix combustion burner and the diffusion flame burner.
• the air required for combustion, is mixed with the burner fuel before delivery to the combustion zone.
• the fuel In the diffusion flame burner, the fuel is not mixed with the air ahead of the combustion zone, but delivered as pure fuel in the immediate vicinity of the combustion zone. Diffusion flame burners provide good flame stability. The NOx production is relatively high. Low emission gas turbine engines often use a combustor with two operating modes including a pilot nozzle that forms a diffusion flame and a plurality of main nozzles for discharging a fuel/air mixture to form premixed flames as the main combustion around the diffusion flame.
• the US 5,901,555 describes a conventional gas turbine with the main burners divided into a plurality of groups in accordance with the load. The flow rate of the pilot fuel is increased when the gas turbine load is low, to achieve stable combustion.
• An object of the invention is to provide an improved fuel distributor .
• An inventive fuel distributor uses the pressure gradient across the combustion system to control the proportion of fuel provided to different areas of the combustion system. These areas could provide pilot fuel at low loads, or better mixing of the fuel and air at high loads.
• the system comprises a cavity with an inlet opening and at least two fuel injection openings.
• the fuel distributor relies on having a larger injection opening arranged in the cavity of the fuel distributor in an upstream section, relative to the flow of compressor air, and a smaller injection opening arranged in the cavity in a downstream section, relative to the flow of compressor air, and serving as feed near combustor pressure.
• a restrictor is arranged at the inlet opening to balance between the fuel flows through the at least one smaller outlet opening and the at least one larger third opening, respectively.
• the restrictor is adjustable to adapt the pressure for different fuel types.
• the third opening with a larger cross-sectional area and exposed to higher external air pressure as main fuel injection opening.
• the principle of the fuel distributor is applied to a diffusion flame burner, where the fuel distributor has a tubular form with the outlet opening at the end of the tube facing the combustion chamber and with third openings arranged upstream the tube, relative to the flow of the fuel. At low fuel flows, the majority of the fuel will enter the combustion chamber through the outlet opening. Compressor air can enter the fuel distributor through the third openings and give some premixing of the fuel and the air. As the fuel flow increases, the pressure in the cavity increases and fuel will spill out through the third openings and will mix with compressor air and enter the combustion chamber .
• the principle of the fuel distributor is applied to a swirler.
• the cavity of the fuel distributor is arranged in the base plate of the swirler.
• the fuel openings and the third openings are arranged in the mixing ducts, that is, in the passages of the swirler.
• the openings may be arranged in the base plate of the swirler or in the swirler vanes. If arranged in the swirler vanes, the arrangement could be at different heights to improve the fuel distribution over the swirler vane height. Smaller fuel outlet openings would be closer to the swirler exit hole with lower pressure. Larger third openings would rather be in an upstream part of the swirler passages relative to the flow of compressor air, with higher pressure.
• the fuel outlet openings would serve as pilot and the third openings as main fuel injection openings.
• the pressure drop of the air between an outlet opening and a third opening in a mixing duct or a swirler passage is controlled by making the mixing duct or swirler passage convergent or divergent.
• the inventive fuel distributor provides an increasing level of premix as the fuel flow increases.
• the inventive fuel distributor even provides some premixing of fuel and air at low flows, thus further reducing NOx emissions.
• the fuel/air mixing within a premix duct like e.g. a swirler passage can be varied as the fuel flow changes without the use of control valves, thus reducing costs and increasing reliability.
• Figure 1 represents an inventive diffusion flame burner at low fuel flow
• Figure 2 represents an inventive diffusion flame burner at high fuel flow
• Figure 3 represents a swirler
• Figure 4 represents a fuel distributor arranged in a swirler base plate with openings in the swirler base plate at low fuel flow
• Figure 5 represents a fuel distributor arranged in a swirler base plate with openings in the swirler base plate at high fuel flow
• Figure 6 represents a fuel distributor arranged in a swirler base plate with openings in the side face of a swirler vane
• Figure 7 shows a swirler vane corresponding to the fuel distributor of Figure 7
• Figure 8 shows the percentage of mass flow through the fuel injection openings as a function of the fuel mass flow
• Figure 9 represents a fuel distributor arranged in a swirler base plate with openings in the side face of a swirler vane and converging swirler passage.
• FIG. 1 shows the scheme of the inventive fuel distributor 1 applied in a diffusion flame burner 2.
• the fuel distributor 1 comprises a distribution element 18 defining a cavity 3 with an inlet opening 4, an outlet opening 5, opposing the inlet opening 4, and two third openings 6.
• the third openings 6 are larger than the outlet opening 5.
• a restrictor 7 is arranged upstream the inlet opening 4 relative to the fuel flow 8, and sized to give the correct pressure to balance the fuel flows 8 between the outlet opening 5 and the third openings 6.
• Pressure Pl at the third openings 6 is greater than pressure P2 at the outlet opening 5.
• the majority of the fuel 8 will enter the combustion chamber 9 through the outlet opening 5.
• air 10 may enter the cavity 3 through third openings 6 and give some premixing of the fuel 8 and air 10.
• the pressure in the cavity 3 increases.
• Pl fuel 8 will spill out of the third openings 6, as shown in Figure 2, and mix with air 10. The fuel/air premix will then enter the combustion chamber 9.
• the swirler 11 for a gas turbine engine is shown.
• the swirler 11 comprises swirler vanes 12 arranged on a swirler vane support 13.
• the swirler vanes 12 can be fixed to a burner head (not shown) with their sides showing away from the swirler vane support 13.
• swirler passages 14 are formed between neighbouring swirler vanes 12 .
• the swirler passages 14 extend between a swirler passage inlet opening 15 and a swirler passage outlet opening 16.
• the swirler passages 14 are delimited by opposing side faces 16 of swirler vanes
• Outlet openings 5 and third openings 6 are arranged in the swirler passages 14 in the swirler vane support 13.
• FIG. 4 a cross-sectional view of an inventive fuel distributor 1 arranged in a swirler vane support 13 is shown.
• the outlet opening 5 and the third opening 6 open out into a swirler passage 14.
• Compressor air 10 is entering the swirler passage 14 from the left by the swirler passage inlet opening 15, where the pressure Pl exceeds the pressure P2 at the swirler passage outlet opening 16.
• Figure 4 shows the fuel distributor at low loads.
• Fuel 8 enters the cavity 3 of the fuel distributor 1 by the inlet opening 4 through the restrictor 7. A predominant proportion of the fuel 8 enters the swirler passage 14 through the outlet opening 5. Only a small amount of fuel 8 enters the swirler passage 14 through the third opening 6. This is beneficial for providing pilot fuel to the outlet opening 5.
• Figures 6 and 7 show an alternative arrangement where the distribution of the fuel flow 8 across the height of the swirler passage 14 could be varied.
• the cavity 3 of the fuel distributor 1 is again arranged in the swirler vane support 13.
• the outlet opening 5 and the third opening 6 are arranged at different heights of the swirler vane 12 in the swirler passage 14.
• the outlet opening 5 has a smaller cross- sectional area and is arranged close to the swirler passage outlet opening 16, where the pressure is low
• the third opening 6 has a larger cross-sectional area and is arranged close to the swirler passage inlet opening 15, where the pressure is higher than at the swirler passage outlet opening 16.
• Figure 9 shows a further embodiment of the inventive fuel distributor 1.
• the general layout is similar to the embodiment described in Figure 6.
• the pressure drop of the air 10 in the swirler passage 14 between the outlet opening 5 and the third opening 6 is varied by making the swirler passage 14 convergent (as shown in Figure 9) or divergent (not shown) .

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Fuel-Injection Apparatus (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)

Priority Applications (1)

Applications Claiming Priority (3)

Publications (2)

Family

ID=38573478

Family Applications (2)

Family Applications Before (1)

Country Status (5)

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Family Cites Families (7)

• 2007
  • 2007-05-18 EP EP07009960A patent/EP1992878A1/fr not_active Withdrawn
• 2008
  • 2008-05-09 EP EP08750236A patent/EP2147256B1/fr not_active Not-in-force
  • 2008-05-09 CN CN2008800165789A patent/CN101688669B/zh not_active Expired - Fee Related
  • 2008-05-09 RU RU2009147021/06A patent/RU2470228C2/ru not_active IP Right Cessation
  • 2008-05-09 WO PCT/EP2008/055762 patent/WO2008141955A1/fr not_active Ceased
  • 2008-05-09 AT AT08750236T patent/ATE549582T1/de active

Non-Patent Citations (1)

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