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
  • 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
  • F23D—BURNERS
  • F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
  • F23D2900/00016—Preventing or reducing deposit build-up on burner parts, e.g. from carbon
• • 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
  • F23R2900/00—Special features of, or arrangements for continuous combustion chambers; Combustion processes therefor
  • F23R2900/00004—Preventing formation of deposits on surfaces of gas turbine components, e.g. coke deposits
• • 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
  • F23R3/283—Attaching or cooling of fuel injecting means including supports for fuel injectors, stems, or lances

Definitions

• the invention relates to the general field of fuel injectors which equip the combustion chamber of a turbomachine, in particular a turbomachine of the type intended for the propulsion of aircraft.
• the combustion chambers of turbomachinery are generally equipped with fuel injectors associated with premix systems, commonly called “injection systems”, generally comprising one or more tendrils (axial and / or radial) , also called “whirlpools", which use the air coming from a compressor arranged upstream of the combustion chamber to atomize the fuel in the combustion chamber.
• injection systems generally comprising one or more tendrils (axial and / or radial) , also called “whirlpools”, which use the air coming from a compressor arranged upstream of the combustion chamber to atomize the fuel in the combustion chamber.
• aerodynamic injectors which mainly use the pressure and speed of the air leaving the compressor to rotate the fuel leaving the injector nose
• aeromechanical injectors which use mainly the fuel pressure inside the injector nose to rotate and spray the fuel.
• the noses of the dual fuel circuit injectors comprise a primary fuel circuit, also called the pilot circuit, comprising a primary fuel spin supplying a primary injector (also called the pilot injector) arranged on an axis of the injector nose, and a secondary fuel circuit, also called the main circuit, comprising a secondary fuel spin supplying a secondary injector (also called the main injector) arranged around the primary injector.
• a primary fuel circuit also called the pilot circuit
• a secondary fuel circuit also called the main circuit
• a secondary fuel circuit also called the main circuit
• a secondary fuel spin supplying a secondary injector also called the main injector
• These can be aeromechanical injectors or a combination of an aeromechanical primary injector and an aerodynamic secondary injector.
• the primary circuit is generally intended to supply the combustion chamber with fuel at all speeds, in particular during the ignition and winding phases, that is to say the propagation of the flame to neighboring sectors.
• the secondary circuit is intended to supply the engine at speeds ranging from cruising flight to takeoff.
• the injector noses are generally subjected to the high temperatures of the combustion chamber, which causes a risk of coking of the fuel stagnating within the secondary fuel circuit at the speeds of the turbomachine at which the secondary injector does not is not in operation.
• a known solution consists in arranging a cooling air circuit at the periphery of the injector nose in order to ensure thermal protection and thermal cooling of the entire injector nose.
• the invention particularly aims to remedy this problem while limiting the radial size of the injector nose.
• an injector nose for a turbomachine comprising a primary fuel circuit terminated by a fuel ejection nozzle opening onto an injection axis, and a secondary fuel circuit.
• a primary fuel circuit terminated by a fuel ejection nozzle opening onto an injection axis
• a secondary fuel circuit comprising an annular fuel ejection end part arranged around the fuel ejection nozzle, and in which an upstream part of the primary fuel circuit, housed in the injector nose, comprises an annular channel extending around the secondary fuel circuit and delimited by an external wall of the injector nose.
• the injector nose further comprises air inlet channels extending through the annular channel of the primary fuel circuit and having respective inlets opening in the external wall and respective outlets opening into an annular air injection channel arranged radially inwards relative to the terminal fuel ejection part, around the fuel ejection nozzle, and cooperating with the terminal fuel ejection part to form an aerodynamic secondary injector.
• the upstream part of the primary circuit thus makes it possible to provide thermal protection and the cooling of the injector nose, in particular of the secondary circuit around which extends the upstream part of the primary circuit.
• air inlet channels which extend through the annular channel of the primary fuel circuit and have respective inlets opening in the external wall and respective outlets opening into an annular channel.
• air injection arrangement arranged radially inwards relative to the terminal fuel ejection part, allows the injection of air intended to mix with the fuel of the secondary fuel circuit within the injector nose , in a particularly compact manner, especially in the radial direction.
• the primary fuel circuit comprises primary connection channels connecting the upstream part of the primary fuel circuit to the fuel ejection nozzle and comprising respective inlets and respective outlets, the respective inlets being arranged radially towards the outside with respect to the respective outputs.
• the secondary fuel circuit comprises a tubular channel centered on the injection axis and which divides, at a downstream end, into several secondary connection channels each shaped to move away from the injection axis in a direction from upstream to downstream, and each arranged between two consecutive primary connection channels.
• the annular channel of the upstream part of the primary fuel circuit is arranged around the tubular channel and around the secondary connection channels of the secondary fuel circuit.
• the secondary fuel circuit comprises a secondary fuel twist formed by twist channels having respective upstream ends, and having respective downstream ends opening into the terminal fuel ejection portion.
• the secondary fuel circuit includes an annular secondary plenum to which the respective upstream ends of the twist channels forming the secondary fuel twist are connected.
• the annular channel of the upstream part of the primary fuel circuit extends downstream beyond the primary connection channels so as to form an annular end chamber surrounding the secondary fuel spin.
• each twist channel has a passage section which reduces in a direction from the upstream end to the downstream end of the twist channel.
• the secondary fuel circuit includes an annular secondary plenum to which the respective upstream ends of the twist channels forming the secondary fuel twist are connected.
• the invention also relates to an injection module for a turbomachine, comprising an injection system, and an injector nose of the type described above, in which the injection system comprises, from upstream to downstream , a socket in which the injector nose is mounted, at least one air intake spin opening downstream of the injector nose, and a bowl.
• the invention also relates to a turbomachine, comprising at least one injector nose of the type described above, or at least one injection module of the type described above.
• FIG. 1 is a schematic view in axial section of a turbomachine according to a preferred embodiment of the invention
• FIG. 2 a schematic view in axial section of a combustion chamber of the turbomachine of Figure 1;
• FIG. 3 is a schematic perspective view in axial section of an injector nose fitted to the combustion chamber of Figure 2;
• FIG. 4 is a schematic perspective view in axial section of the injector nose of Figure 3 without a terminal nozzle of a primary fuel system, and seen from a different angle;
• FIG. 5 is a schematic perspective view in oblique section of the injector nose of Figure 3;
• FIG. 6 is a schematic view of the injector nose of Figure 3, seen from the front from downstream;
• FIG. 7 is a schematic perspective view of the injector nose of Figure 3.
• FIG. 8 is a partial schematic perspective view of the primary fuel circuit of the injector nose of Figure 3;
• FIG. 9 is a partial schematic perspective view of a secondary fuel circuit of the nozzle nose of Figure 3.
• FIG. 9A is a view on a larger scale of part of FIG. 9.
• FIG. 1 illustrates a turbomachine 10 for an aircraft of a known type, generally comprising a fan 12 intended for the suction of an air flow dividing downstream of the fan into a primary flow circulating in a channel d primary flow, hereinafter referred to as primary vein PF, within a core of the turbomachine, and a secondary flow bypassing this core in a secondary flow flow channel, hereinafter referred to as secondary vein SF.
• primary vein PF a primary flow circulating in a channel d primary flow
• secondary vein SF secondary flow bypassing this core in a secondary flow flow channel
• the turbomachine is for example of the double flow and double body type.
• the heart of the turbomachine thus 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 turbomachine is faired by a nacelle 24 surrounding the secondary stream SF. Furthermore, the rotors of the turbomachine are rotatably mounted about a longitudinal axis 28 of the turbomachine.
• the longitudinal direction X is the direction of the longitudinal axis 28.
• the radial direction R is at all points a direction orthogonal to and passing through the longitudinal axis 28, and the circumferential or tangential direction C is at all points a direction orthogonal to the radial direction R and to the longitudinal axis 28.
• the terms “internal” and “external” refer respectively to a relative proximity, and a relative distance, of an element with respect to the longitudinal axis 28.
• the "upstream” and “downstream” directions are defined by reference to the general direction of gas flow in the primary PF and secondary SF streams of the turbomachine.
• FIG. 2 represents the combustion chamber 18 of the turbomachine 10 of FIG. 1 and its immediate environment.
• this combustion chamber which is for example of the annular type, comprises two coaxial annular walls, respectively radially internal 32 and radially external 34, which extend from upstream to downstream, in the direction 36 d flow of the primary flow of gas in the turbomachine, around the longitudinal axis 28 of the turbomachine.
• These internal annular walls 32 and external 34 are connected to each other at their upstream end by an annular chamber wall 40 which extends substantially radially around the longitudinal axis 28.
• This annular chamber wall 40 is equipped with injection systems 42 distributed around the longitudinal axis 28, one of which is visible in FIG. 2, each receiving an injector nose 43 mounted at the end of an injector rod 45, to allow the injection of a premix of air and fuel centered on a respective injection axis 44.
• each injection system 42 comprises a socket 46, commonly known as a “sliding bushing", in which the corresponding injector nose 43 is mounted with a sliding capacity to allow differential thermal expansion in operation.
• the sleeve 46 internally delimits a single air intake tendril 48, for example of the axial type, formed within the injection system 42.
• Each injection system 42 further comprises a divergent bowl 49 arranged at the outlet of the air intake spin 48 and opening into the combustion chamber 18.
• the assembly formed by an injection system 42 and the corresponding injector nose 43 constitutes an injection module, in the terminology of the present invention.
• part 50 of an air flow 52 coming from a diffuser 54 and coming from the high pressure compressor 16 feeds the injection systems 42, while another part 56 of the air flow 52 feeds air inlet orifices 58 formed in the walls 32 and 34 of the combustion chamber, in a well known manner.
• the radial direction R ' is at all points a direction orthogonal to and passing through the injection axis 44
• the circumferential or tangential direction C' is at all points a direction orthogonal to the radial direction R 'and to the injection axis 44.
• a transverse plane is defined as a plane orthogonal to the injection axis 44, while an axial plane is defined as a plane containing the injection axis 44.
• FIGS. 3 to 9 illustrate in more detail an injector nose 43 according to a preferred embodiment of the invention.
• the injector nose 43 comprises a body 60, preferably in one piece, comprising a nozzle 61 (FIGS. 3 and 5) by which the injector nose 43 is intended to be connected to an injector rod 45 as in FIG. 2 .
• a primary circuit 62 Within the body 60 are formed two fuel circuits, namely a primary circuit 62 and a secondary circuit 64 ( Figure 3).
• the primary circuit 62 ends with a central fuel ejection nozzle 66 of aeromechanical type, while the secondary circuit 64 has a terminal fuel ejection nozzle 68 of aerodynamic type arranged around the fuel ejection nozzle 66 ( Figures 3-6), as will appear more clearly in the following.
• the primary circuit 62 comprises an annular channel 70 defined between an external wall 72, of generally annular shape, of the body 60 (FIGS. 3-7) which delimits the latter externally, and an internal envelope 74 generally annular and of complex shape, shown isolated. in figure 8.
• the primary circuit 62 also includes primary connection channels 76 (FIGS. 3, 4 and 8) which connect the annular channel 70 to an inlet chamber 78 (FIGS. 3 and 4) of the fuel ejection nozzle 66.
• the canals of primary connections 76 are for example four in number and are preferably regularly distributed around the injection axis 44.
• the inlet chamber 78 is arranged in the injection axis 44, radially inwards relative to the annular channel 70.
• the primary connection channels 76 thus have respective inlets connected to the annular channel 70, and respective outlets connected to the inlet chamber 78.
• the respective inlets of the primary connection channels 76 are arranged radially outward relative to their respective outputs.
• the primary connection channels 76 extend in respective directions substantially orthogonal to the injection axis 44, for example substantially radial.
• the annular channel 70 extends downstream beyond the primary connection channels 76 so as to form an annular terminal chamber 79.
• the fuel ejection nozzle 66 has a core 80 which is part of the body 60 and which is centered on the injection axis 44 and arranged at a downstream end of the inlet chamber 78 (FIGS. 3 to 6).
• the core 80 has an upstream portion 82 which extends downstream into an annular surface 84 which internally delimits a primary stilling chamber 86 of annular shape within the fuel ejection nozzle 66.
• Injection channels 88 ortho-radial ( Figures 4 and 6) , that is to say orthogonal to the injection axis 44 and not intersecting with the latter, connect a downstream end of the primary still chamber 86 to a converging swirl chamber 90 (FIG. 3).
• the orientation of the injection channels 88 makes it possible to promote the gyration of the fuel within the swirl chamber 90.
• the primary circuit 62 and more particularly the fuel ejection nozzle 66, comprises a terminal nozzle 92 (FIGS. 3 and 5) which is mounted on a downstream end of the body 60 and which externally delimits the primary still chamber 86 and the swirl chamber 90.
• This end piece 92 has a upstream part of cylindrical shape of revolution externally delimiting the primary still chamber 86, and a downstream part of frustoconical shape externally delimiting the swirl chamber 90 and terminated by a fuel ejection orifice 93 (FIG. 3) intended to diffuse in the form spray the fuel from the swirl chamber 90.
• FIG. 9 shows the internal volume of the secondary circuit 64, that is to say the space occupied by the fuel in operation.
• the walls delimiting the different parts of the secondary circuit 64 which will be described are visible as reliefs within the internal envelope 74 of the primary circuit 62, visible in FIG. 8.
• the secondary circuit 64 comprises a tubular channel 100 (of which only one end part is shown in the figures), centered on the injection axis 44, and delimited externally by a cylindrical wall 102 (of which only one end part is shown in the Figures), which internally delimits an upstream part of the annular channel 70 of the primary circuit (and which therefore forms an upstream part of the above-mentioned internal envelope 74).
• the tubular channel 100 is divided, at its downstream end, into four secondary connection channels 104 regularly distributed around the axis injection 44 and each shaped to move away from the injection axis 44 in the direction from upstream to downstream.
• Each of the secondary connection channels 104 is for example inscribed in a respective axial plane.
• the secondary connection channels 104 have respective downstream ends opening onto an upstream end surface 106 of a secondary plenum chamber 108 of annular shape, centered on the injection axis 44.
• This secondary plenum chamber 108 is delimited downstream by a downstream end surface 110 into which respective upstream ends 111 open of twist channels 112 forming a secondary fuel twist 114.
• the spin channels 112 have respective downstream ends 115 (FIGS. 4, 6 and 9) opening into an annular space constituting the terminal ejection portion 68 of the secondary circuit 64.
• this space annular is delimited externally by an annular outer lip 116 of the body 60 having a free end 117, and is delimited internally by an annular internal lip 118 of the body 60 having a free end 119.
• the secondary plenum 108 and the spin channels 112 extend around an annular wall 120 which extends downstream forming the internal lip 118, and which has an internal radius RI which is for example greater than an outside radius R2 of the cylindrical wall 102 which internally delimits the upstream part of the annular channel 70 of the primary circuit.
• the secondary connection channels 104 each form, with the injection axis 44, an angle W which is preferably between 30 degrees and 60 degrees, and which is for example equal to 45 degrees (Figure 4).
• the secondary connection channels 104 delimit, in pairs, spaces, respectively forming the primary connection channels 76 belonging to the primary circuit 62.
• the secondary fuel spin 114 is surrounded by the annular terminal chamber 79 which extends the annular channel 70 of the primary circuit 62.
• the injector nose 43 also incorporates an air inlet screw 122 (FIGS. 4, 5 and 8) and an annular air injection channel 124 cooperating with the terminal ejection portion 68 of the secondary circuit 64 to form an aerodynamic secondary injector.
• the air inlet spin 122 is formed of air inlet channels 126, for example four in number, having respective inlets 128 (FIG. 7) opening into the external wall 72 of the body 60, and respective outlets 130 (FIGS. 4-6) opening into the annular air injection channel 124, preferably in a substantially orthoradial manner in order to promote the gyration of the air around the injection axis 44.
• the air inlet channels 126 extend through the annular channel 70 of the primary circuit 62, between the secondary connection channels 104 ( Figure 8).
• the annular air injection channel 124 is delimited externally by the annular wall 120, and internally by the fuel ejection nozzle 66, in particular by the terminal nozzle 92 (FIGS. 3 and 4).
• the annular air injection channel 124 is thus arranged radially inside with respect to the terminal fuel ejection portion 68 and is arranged around the fuel ejection nozzle 66.
• an upstream part of the primary circuit 62 housed in the injector nose 43, and in this case formed by the annular channel 70 and the terminal annular chamber 79, extends around the secondary circuit 64.
• This upstream part of the primary circuit 62 is delimited externally by the external wall 72 of the body 60 of the injector nose, so that the upstream part of the primary circuit 62 extends around the periphery of the injector nose.
• the upstream part of the primary circuit 62 thus makes it possible to provide thermal protection and the cooling of the injector nose 43.
• annular end chamber 79 ensures the thermal protection and cooling effect of the injector nose 43 beyond the primary connection channels 76, in the downstream direction, and in particular allows provide thermal protection and cooling of the secondary fuel spin 114.
• the spin channels 112 each extend along a respective plane P forming an acute angle Q with the direction D of the injection axis, preferably between 40 degrees and 60 degrees, and by example equal to 50 degrees.
• each of the twist channels 112, forming the secondary fuel spin 114 has an evolving passage section, which reduces in the direction going from the upstream end 111 towards the downstream end 115 of the channel.
• the reduction of the passage section between the upstream end and the downstream end of each of the twist channels 112 is preferably between 10 and 50 percent of the passage section at the upstream end of the channel.
• each of the twist channels 112 makes it possible to increase the pressure drop between the entry and the exit of the secondary fuel twist 114 and in particular thus to accelerate the fuel within the secondary twist. of fuel 114, while allowing lower fuel flow rates at equal pressure at the inlet of the secondary spin.
• the passage section at the inlet of each of the twist channels 112 is for example equal to 0.2 mm 2 .
• each of the spin channels 112 is curved in the corresponding plane P, so that a direction DI tangent to a mean line L of the channel at the level of the downstream end 115 of the latter forms an angle a with a direction D2 tangent to the mean line L of the channel at the upstream end 111 of the latter.
• the angle a is preferably between 5 degrees and 15 degrees, and is for example equal to 8 degrees. Because of its curvature, each of the twist channels 112 extends substantially at a constant distance from the injection axis 44, from the upstream end to the downstream end of the channel 112.
• the body 60 is preferably produced by additive manufacturing. In the example illustrated, this body 60 forms the entire injector nose 43 with the exception of the end piece 92. Additive manufacturing techniques are in fact particularly advantageous for producing the body 60 due to the geometry complex of the latter.
• fuel circulates in the primary circuit 62 and is ejected in the form of a jet at the outlet of the fuel ejection nozzle 66, whatever the speed of the turbomachine.
• fuel also circulates in the secondary circuit 64.
• This fuel is rotated and accelerated by passing through the spin channels 112 forming the secondary spin of fuel 114, and forms, at the outlet thereof, a swirling fuel film within the terminal ejection portion 68 of the secondary circuit 64.
• the air flow set in rotation by the air inlet spin 122, and introduced into the annular air injection channel 124, has a flow rate sufficient to shear the fuel film at level of the free end 119 of the internal lip 118 and of the free end 117 of the external lip 116.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Fuel-Injection Apparatus (AREA)

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Publications (2)

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• 2018
  • 2018-12-27 FR FR1874261A patent/FR3091333B1/fr active Active
• 2019
  • 2019-12-26 CA CA3122612A patent/CA3122612A1/en active Pending
  • 2019-12-26 EP EP19848993.2A patent/EP3877699B1/de active Active
  • 2019-12-26 WO PCT/FR2019/053302 patent/WO2020136359A1/fr unknown
  • 2019-12-26 CN CN201980086319.1A patent/CN113227656B/zh active Active
  • 2019-12-26 US US17/417,505 patent/US11788727B2/en active Active

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