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
• • 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
  • 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
• • 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
  • 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
  • F23R3/42—Continuous combustion chambers using liquid or gaseous fuel characterised by the arrangement or form of the flame tubes or combustion chambers

Definitions

• the present invention relates to the field of aircraft turbomachines and more particularly relates to an air intake ring intended to be part of a fuel injection system and air in a combustion chamber within a combustion chamber. turbine engine.
• FIG. 1 appended illustrates a turbine engine 10 for an aircraft of a known type, for example a turbojet engine, generally comprising a fan 12 intended for the suction of an air flow dividing downstream of the fan. in a primary flow supplying a heart of the turbomachine and a secondary flow bypassing the heart.
• the heart of the turbomachine generally comprises a low-pressure compressor 14, a high-pressure compressor 16, a combustion chamber 18, a high-pressure turbine 20 and a low-pressure turbine 22.
• the turbine engine is streamlined by a nacelle 24 surrounding the flow space 26 of the secondary flow.
• the rotors of the turbomachine are rotatably mounted about a longitudinal axis 28 of the turbomachine.
• FIG. 2 represents the combustion chamber 18 of the turbomachine of FIG. 1.
• this combustion chamber which is of annular type, comprises two coaxial annular walls, respectively radially inner 32 and radially outer 34, which extend from upstream to downstream, in the flow direction 36 of the primary flow of gas in the turbomachine, around the axis of the combustion chamber which merges with the axis 28 of the turbomachine.
• These inner and outer annular walls 32 are interconnected at their upstream end by an annular bottom wall of chamber 40 which extends substantially radially about the axis 28.
• This annular bottom wall of chamber 40 is equipped with injection systems 42 distributed around the axis 28 to allow the injection of a premix of air and fuel centered along an injection axis 44.
• a portion 46 of an air flow 48 coming from the compressor 16 feeds the injection systems 42 while another part 50 of this air flow bypasses the combustion chamber while flowing towards the downstream along the coaxial walls 32 and 34 of this chamber and allows in particular the supply of air orifices provided within these walls 32 and 34.
• FIG. 3 is an axial half-sectional view of one of the injection systems 42.
• This generally comprises a head 52 of a fuel injector, a bush 54, sometimes referred to as a “sliding bushing".
• a bush 54 sometimes referred to as a "sliding bushing"
• the head 52 of the injector is mounted, an air intake ring 56, and a bowl 58, sometimes referred to as "mixing bowl”.
• the air intake ring 56 has a generally circular shape around the injection axis 44, this axis therefore constituting an axis of revolution for the air intake ring 56.
• the air intake crown 56 comprises an annular partition wall 60 which divides the air intake crown into an upstream air circulation space 62 and a downstream air circulation space 64. These two spaces are commonly called “tendrils”.
• the annular separation wall 60 extends radially inwardly into an annular deflection wall 66, commonly called "venturi", having an internal profile 68 of convergent-divergent shape having in particular a collar 70, as well as an external profile. 72.
• Each of the upstream and downstream air circulation spaces 62 and 62 is traversed by fins 74 allowing the air to be swirled around the axis of revolution 44 of the air intake ring.
• a part of the air 46 supplying the injection system enters the air circulation spaces 62 and 64 of the air intake ring 56 and continues its course in the form of air flow.
• fuel is ejected by the head 52 of the injector, in the form of a cone 80 of angle ⁇ with respect to the injection axis 44.
• the fuel arrives at the downstream end of the internal profile 68, the fuel meets the flow of air 78 flowing along the outer profile 72 of the annular deflection wall 66.
• This air flow 78 induces a shearing effect which drives the fuel to detach from the annular deflection wall by forming droplets suspended in the air.
• the portion of the internal profile 68 covered by the fuel film 82 thus forms an annular region 83, which extends to the downstream end of the internal profile 68.
• the fuel droplets detached from the annular deflection wall are designed to evaporate into the air, preferably before reaching the combustion chamber firebox inlet.
• the evaporation of the droplets is favored, as far as possible, by the turbulence induced by the meeting of the air flows 76 and 78 flowing respectively on either side of the annular deflection wall.
• the invention aims in particular to provide a simple, economical and effective solution to this problem.
• an air intake ring for a turbomachine combustion chamber injection system having an axis of revolution, and comprising an annular partition wall which divides the air intake crown into one. an upstream air circulation space and a downstream air circulation space which extends radially inwardly into an annular deflection wall having an internal profile having a convergent-divergent shape.
• the internal profile of the annular deflection wall has a recess inducing an increase in the radius of the internal profile downstream of said recess.
• the recess induces the presence of a stop at the downstream end of an upstream portion of the internal profile.
• the fuel dripping on the internal profile thus tends to detach at this stop, which is caused by the flow of air flowing along the internal profile, resulting from the upstream air circulation space.
• the separation of the fuel into droplets therefore takes place further upstream than with the air intake crowns of known type.
• the droplets thus have a larger volume to evaporate with penetrating the combustion chamber.
• the recess creates a recirculation zone downstream thereof and induces turbulence, conducive to the mixing of fuel and air, and further making possible a thickening of the flame front.
• the invention thus makes it possible to improve the combustion efficiency.
• the recess is formed at a neck of the inner profile of the annular deflection wall.
• said recess preferably defines a shoulder extending orthogonally to said axis of revolution of the air intake crown.
• each of the upstream and downstream air circulation spaces is traversed by fins allowing the air to gyrate around said axis of revolution of the air intake crown.
• the invention also relates to an injection system for a turbomachine combustion chamber, comprising a fuel injector head, and an air intake ring of the type described above, in which the head of fuel injector is configured to spray fuel on an annular region of the inner profile of the annular deflection wall, and wherein the recess is formed downstream of an upstream end of said annular region of the inner profile.
• the invention also relates to a combustion chamber for a turbomachine, comprising at least one injection system of the type described above.
• the invention also relates to a turbomachine, particularly for an aircraft, comprising at least one combustion chamber of the type described above.
• the invention relates to a method for atomizing fuel in an injection system of the type described above, fitted to a turbomachine combustion chamber, in which fuel from the injector head flows on the internal profile of the engine.
• the annular deflection wall and detaches from this internal profile at the recess of the latter so as to form droplets within a stream of air from the upstream air circulation space of the crown of air intake and circulating along the inner profile of the annular deflection wall.
• FIG. 1, already described is a partial schematic view in axial section of a turbomachine of a known type
• - Figure 2 already described, is a partial schematic view in axial section of a combustion chamber of the turbomachine of Figure 1;
• FIG. 3 is a partial schematic half-view in axial section of an injection system fitted to the combustion chamber of FIG. 2;
• FIG. 4 is a view similar to FIG. 3, illustrating an injection system comprising an air intake crown according to a preferred embodiment of the invention
• FIG. 5 is an enlarged view of part of FIG.
• FIGS. 4 and 5 illustrate an injection system 42 which is generally similar to the injection system of FIGS. 1 to 3 but which differs from it in that it comprises an air intake crown 56 according to a mode preferred embodiment of the invention.
• This air intake ring 56 has the particularity that the internal profile 68 of the annular deflection wall 66 has a recess 90 inducing an increase in radius ⁇ of the internal profile downstream of this recess 90.
• a downstream part of the internal profile 68 is set back, that is to say offset radially outwards, with respect to an upstream portion of this internal profile 68.
• the recess 90 induces the presence of a stop 92 at the downstream end of the upstream portion of the internal profile.
• the recess 90 is formed downstream of an upstream end 93 of the annular region 83 of the internal profile 68, on which the film of fuel 82 flows.
• the fuel forming the fuel film 82 dripping on the internal profile 68 tends to detach at this stop 92, driven by the air flow 76 flowing along the internal profile 68.
• the separation of the fuel into droplets, or atomization, therefore takes place further upstream than with the air intake crowns of known type.
• the droplets thus have a larger volume to evaporate with penetrating the combustion chamber.
• the recess 90 creates a recirculation zone downstream thereof and induces turbulence, conducive to the mixing of fuel and air, and making possible a thickening of the flame front.
• the invention thus improves the mixture of air and fuel, and thus improve the combustion efficiency.
• the recess 90 is formed at the neck 70 of the internal profile 68.
• the separation of the fuel into droplets takes place where the speed of the airflow 76 flowing along the internal profile 68 is the largest. This minimizes the size of the generated fuel droplets.
• the recess defines a shoulder 94 extending orthogonally to the axis of revolution 44 of the air intake ring 56 (FIG. 5).
• the injection system 42 equips a combustion chamber similar to the combustion chamber of FIG. 2 in a turbomachine similar to the turbomachine of FIG. 1.
• the injection system therefore allows the implementation of a fuel atomization process, in which fuel from the injector head 52 flows on the inner profile 68 of the annular deflection wall 66, and detaches of this internal profile 68 at the recess 90 of the latter so as to form droplets within the air flow 76 from the upstream air circulation space 62 of the air intake ring 56 and flowing along the internal profile 68.
• the invention makes it possible to reduce the poor quenching richness and to reduce CO / CH emissions.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Fuel-Injection Apparatus (AREA)
• Nozzles For Spraying Of Liquid Fuel (AREA)
• Combustion Methods Of Internal-Combustion Engines (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=53059178

Family Applications (1)

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• 2014
  • 2014-12-03 FR FR1461862A patent/FR3029608B1/fr active Active
• 2015
  • 2015-12-02 EP EP15817462.3A patent/EP3227612B1/de active Active
  • 2015-12-02 WO PCT/FR2015/053296 patent/WO2016087780A1/fr active Application Filing
  • 2015-12-02 CN CN201580065955.8A patent/CN107003003B/zh active Active
  • 2015-12-02 US US15/529,570 patent/US10677463B2/en active Active

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