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
  • 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
• • 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
  • F23D2900/14701—Swirling means inside the mixing tube or chamber to improve premixing

Definitions

• the invention relates to a fuel injection system and improvements for the further diminishment of air pollutants such as nitrogen oxides (NO x ) .
• the first is to use a fine distribution of fuel in the air, generating a fuel/air mixture with a low fuel fraction.
• the thermal mass of the excess air present in the reaction zone of a lean premixed combustor absorbs heat and limits the temperature rise of the products of combustion to a level where thermal NO x is not excessively formed.
• the second measure is to provide a thorough mixing of fuel and air prior to combustion. The better the mixing, the fewer regions exist where the fuel concentration is significantly higher than average, the fewer the regions reaching higher temperatures than average, the lower the fraction of thermal NO x will be.
• premixing of fuel and air in a gas turbine engine takes place by injecting fuel into an air stream in a swirling zone of a combustor which is located upstream from the combustion zone.
• the swirling produces a mixing of fuel and air before the mixture enters the combustion zone.
• An object of the invention is to provide a swirler, allowing for a better pre-mixing of gaseous fuel and compressor air to provide a homogeneous fuel/air mixture and thereby reduce formation of NO x .
• Another objective is to provide a burner with an improved swirler.
• Still another objective is to provide a gas turbine with an improved swirler.
• An inventive swirler incorporates a modified radial swirler assembly.
• the modification is best described by a partly twisted radial swirler.
• None of the prior art is targeting the generation of turbulent secondary flows along the swirl vanes with the specific aim of assisting fuel air mixing.
• the twisted vanes comprise straight parts at the base portions of the twisted vanes.
• This feature provides a well defined shear layer region for any reverse flow into the swirler assembly. This is advantageous because it increases the stability of any flame in that region.
• the height of the straight parts should not exceed 50% of the twisted vanes' height in order to benefit from the turbulent secondary flows generated in the twisted parts. Therefore it is also advantageous to twist the vanes by an angle of up to 120°. However, twisted vanes with angles differing considerably from 120° will also provide desirable turbulent secondary flows.
• Figure 1 shows a perspective view of a prior art radial swirler
• Figure 2 shows a perspective view of a swirler in accordance with the present invention
• Figure 3 shows another perspective view of a swirler with twisted vanes in accordance with the present invention.
• FIG. 1 a typical prior art radial swirler 1 is shown.
• the turning vanes 9 of a radial swirler 1 are arranged on a first plate 2 that is normal to the central axis 3 of the swirler 1 body.
• the vanes 9 are of pie slice type with substantially triangular cross-sections 4 (see Figure 3) and rectangular side faces 13 and a slightly curved outer surface 10.
• the turning vanes 9 are fixed to a second plate 8 with their sides showing away from the first plate 2.
• Swirler passages 14 are formed by opposing side faces 13 of swirler vanes 9, by the surface of the first plate 2 and by a surface of the second plate 8.
• the second plate 8 is connected to a combustion pre-chamber 11.
• This configuration of the swirler 1 forces the airflow (as shown by the arrows) to move within the passages 14 radially inwardly towards the central axis 3 of the swirler 1 body.
• a radial swirler 1 is capable of creating strong swirl and thorough mixing with little concern of the problem of aerodynamic wake flows.
• FIG 2 shows the view of an embodiment of the inventive swirler 1.
• Respective base portions 6 of the turning vanes 9 are arranged on a first plate 2 that is normal to the central axis 3 of the swirler 1 body and the cross-sections 4 (see Figure 3) of the vanes 9 are of substantially triangular shape.
• the vanes 9 are twisted and will be referred to as twisted vanes 5.
• the embodiment of Figure 2 comprises twisted vanes 5 with straight base portions 6 and twisted parts 7.
• the straight base portions 6 have a shape described by a translation of the vane cross-sections 4 (see Figure 3) parallel to the central axis 3 of the swirler 1, whereas the twisted parts 7 have a shape described by a further translation of the vane cross-sections 4 along the central axis 3 superimposed by a rotation of the vane cross- sections 4 about the central axis 3.
• an inventive swirler 1 is shown without second plate 8 and combustor pre-chamber 11 (see Figures 1 and 2) where the twisted vanes 5 are arranged on a first plate 2.
• the substantially triangular vane cross- sections 4 can be seen very clearly in this view.
• Figure 3 shows the turbulent secondary flows 12 generated along the twisted vanes 5, improving fuel/air mixing.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Gas Burners (AREA)
• Turbine Rotor Nozzle Sealing (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=38521629

Family Applications (1)

Country Status (5)

Cited By (1)

Families Citing this family (8)

Citations (5)

Family Cites Families (24)

• 2007
  • 2007-04-23 EP EP07008236A patent/EP1985924A1/en not_active Withdrawn
• 2008
  • 2008-04-17 US US12/597,261 patent/US20100175381A1/en not_active Abandoned
  • 2008-04-17 WO PCT/EP2008/054658 patent/WO2008128955A1/en active Application Filing
  • 2008-04-17 EP EP08736322A patent/EP2137460A1/en not_active Withdrawn
  • 2008-04-17 RU RU2009143010/06A patent/RU2467253C2/ru not_active IP Right Cessation
  • 2008-04-17 CN CN2008800133415A patent/CN101668989B/zh not_active Expired - Fee Related

Patent Citations (5)

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