EP2014988A1 - Optimisation of an anti-coke film in an injection system - Google Patents

Optimisation of an anti-coke film in an injection system Download PDF

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Publication number
EP2014988A1
EP2014988A1 EP08159886A EP08159886A EP2014988A1 EP 2014988 A1 EP2014988 A1 EP 2014988A1 EP 08159886 A EP08159886 A EP 08159886A EP 08159886 A EP08159886 A EP 08159886A EP 2014988 A1 EP2014988 A1 EP 2014988A1
Authority
EP
European Patent Office
Prior art keywords
holes
downstream
main axis
injection system
air
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP08159886A
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German (de)
French (fr)
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EP2014988B1 (en
Inventor
Alain Cayre
Christophe Pieussergues
Jackie Prouteau
Denis Sandelis
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Safran Aircraft Engines SAS
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SNECMA SAS
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Publication of EP2014988A1 publication Critical patent/EP2014988A1/en
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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
    • 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
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2240/00—Components
    • F05D2240/35—Combustors or associated equipment
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2250/00—Geometry
    • F05D2250/30—Arrangement of components
    • F05D2250/32—Arrangement of components according to their shape
    • F05D2250/323—Arrangement of components according to their shape convergent

Definitions

  • the present invention relates to the field of fuel injection systems.
  • the invention more particularly relates to an annular expansion ring centered on a main axis and adapted to be mounted on a fuel injector coaxial with this ring, this ring having holes distributed around this main axis, opening on its upstream face, and allowing the passage of air to the area downstream of this ring.
  • the fuel is injected into a combustion chamber 100 (for example in a combustion chamber of a turbomachine) by an injector 10 which is located at the end of the pipe bringing this fuel .
  • This injector 10 is substantially cylindrical, and has an expansion ring 220 annular with respect to a main axis A and which surrounds a portion of the injector 10, this injector being coaxial with the expansion ring.
  • the expansion ring 220 comprises an axial cylindrical portion 222 whose radially inner surface is in contact with or near the outer surface of the injector 10.
  • this expansion ring 220 The role of this expansion ring 220 is to allow a clearance of the clearance between the injector 10 and the elements of the bottom of the combustion chamber, this game being caused by the thermal stresses to which these parts are subjected. During combustion, it can be created on the downstream end 12 of the injector 10 coke deposits due to improper combustion of the fuel. The coke deposits are undesirable because they degrade the fuel spraying by the injectors 10.
  • upstream and downstream are used in relation to the direction of normal circulation of the fuel at the outlet of the injector (unless specified otherwise), that is to say from the left to the right on the figure 5 .
  • the adjectives "inside” and “outside” are related to the proximity to the main axis A.
  • the expansion ring 220 is pierced with holes 226 oriented substantially axially (that is, in the direction of the main axis A) which allow air to penetrate. axially in the zone located downstream of the injector 10. This air thus penetrates parallel to the circumferential side wall of the injector in the zone upstream thereof and forms a layer or film of air around the injector, which prevents coke is deposited on the downstream end of the injector.
  • these holes 226 are drilled in the radial wall 224 of the expansion ring 220 which extends radially outwardly the downstream end of the cylindrical portion 222 of this ring.
  • the tests and uses in service performed by the Applicant show however that such an air film is the source of disadvantages.
  • parts of the combustion chamber bottom are located immediately downstream of the injector. These include the primary swirler 40, and the venturi 50.
  • the primary swirler 40 is an annular piece coaxial with the injector 10, placed immediately downstream of the expansion ring 220, whose inner diameter is greater than to the diameter of the injector.
  • This primary swirler 40 is pierced around its circumference with primary holes 42 through which the air enters the zone situated downstream of the injector 10.
  • the primary holes 42 are oriented so that their axes lie in a plane radial with respect to the main axis, with a circumferential inclination.
  • the air exiting the primary holes 42 enters the zone downstream of the injector 10 by rotating around the main axis A and forming a swirler or vortex.
  • the venturi 50 Located downstream of the primary swirler 40 is the venturi 50, which is an annular piece coaxial with the injector 10.
  • the venturi 50 has a radial wall which extends downstream (at its inner end) by a convergent 52 , that is to say a conical wall which approaches the main axis A downstream.
  • the convergent 52 is extended by a neck 54, then a divergent 56 which flares downstream.
  • the convergent 52 is therefore downstream of the injector 10, and is located substantially in the axial extension of the holes 226 of the expansion ring 220.
  • the tests carried out by the Applicant have revealed that the air issuing from the holes 226 enters the zone downstream of the injector 10 (and the ring 220) by creating turbulence.
  • the present invention aims to remedy these drawbacks, or at least to mitigate them.
  • the invention aims to propose an expansion ring such that the air coming from the holes which are pierced penetrates into the zone downstream of the injector in a homogeneous manner, and without impacting the downstream end of the injector.
  • the expansion ring comprises a conical annular slot converging downstream, open downstream, the holes opening into the upstream portion of this slot, the axis of each of these holes making with the main axis an angle strictly greater than the angle that makes with this main axis the generatrix of the cone defining the annular slot, such so that the air coming out of the holes impacts the inner wall of the annular slot which is closest to the main axis.
  • the air leaving the holes does not penetrate directly into the downstream zone of the injector, but firstly impacts the inner wall of the annular slot, and is then redirected along the annular slot.
  • the air exits the annular slot in a homogeneous manner that is to say that the air velocity at the outlet of the annular slot is substantially uniform over the outlet orifice of the annular slot, the air flow is not turbulent.
  • the angle of the annular slot with the main axis is such that the air exiting the slot does not impact the surface of the injector. Thus, no coke deposit is produced on the surface of the injector.
  • the expansion ring comprises a cylindrical portion around the main axis, and a radial wall which extends radially outwardly the downstream end of this cylindrical portion, and the annular slot opens downstream at the location or the cylindrical portion joins the radial wall.
  • the holes of the expansion ring have a circumferential inclination with respect to the main axis, which gives the air passing through them a rotational movement about the main axis.
  • this inclination causes an air flow clockwise around the main axis in the direction of the flow of fuel.
  • this inclination generates a flow of air in the opposite direction of the clockwise direction around the main axis in the direction of the flow of the fuel.
  • the invention also aims at providing an injection system comprising an expansion ring such that the air coming from the holes of this ring does not cause coke deposition on the downstream end of the injector, and does not cause no deposit of coke on the convergent venturi, such deposits of coke being undesirable because they degrade the fuel spraying by the injectors.
  • This goal is achieved by the fact that the air leaving the annular slot does not impact the downstream end of the injector and leaves the annular slot in a direction substantially parallel to the direction of flow of the air exiting the primary swirler, so that these two air flows do not mix (or at least only further downstream).
  • the generatrix of the cone defining the annular slot of the expansion ring is with the main axis an angle equal to or greater than the angle made by the convergent of the venturi with this main axis, so that the air coming out of the the annular slot does not impact the convergent of the venturi.
  • the combustion chamber can operate with lower fuel injection rates (lower extinction limit).
  • fuel injection rates lower extinction limit.
  • the figure 1 illustrates a system for injecting a combustion chamber 100 of a turbomachine.
  • This injection system is identical to that shown on the figure 5 , except for the expansion ring.
  • the fuel is injected into a combustion chamber 100 (for example in a combustion chamber of a turbomachine) by an injector 10.
  • This injector 10 is substantially cylindrical, and has an annular expansion ring 20 with respect to a main axis A. and which surrounds a portion of the injector 10, this injector being coaxial with the expansion ring.
  • the expansion ring 20 has a cylindrical portion 22 axial whose radially inner surface is in contact or almost the outer surface of the injector 10.
  • the expansion ring 20 comprises upstream of the cylindrical portion 22 a conical collar 21 which extends this cylindrical portion flaring radially upstream.
  • the cylindrical portion 22 and the flange 21 have a substantially constant thickness.
  • the downstream end of the cylindrical portion 22 of the expansion ring 20 is either slightly upstream or aligned with the downstream end 12 of the injector 10.
  • the downstream end of the cylindrical portion 22 is extended radially outwardly by a radial wall 24, so that the inner face of the cylindrical portion 22 and the downstream face of the radial wall 24 form substantially a right angle.
  • the radial wall 24 has a substantially constant thickness.
  • the expansion ring 20 On the upstream side of the radial wall 24, where this radial wall meets the cylindrical portion 22, the expansion ring 20 has an annular bulge 30 having substantially the shape of a torus.
  • the upstream face of the radial wall 24 is extended upstream by the surface of the annular bulge 30, this surface joining the outer face of the cylindrical portion 22.
  • the line of the upstream face of the radial wall 24 is perpendicular to the main axis A, and extends at right angles upstream by the line of the surface of the annular bulge 30, this line substantially following a quarter circle to the line of the outer face of the cylindrical portion 22.
  • the line of the surface of the annular bulge 30 joins the line of the outer face of the cylindrical portion 22 forming a right angle.
  • the transitions between the surface of the annular bulge 30 and the upstream face of the radial wall 24 or the outer face of the cylindrical portion 22 can also be done with a rounding.
  • the Figures 2 and 3 detail the structure of the expansion ring 20.
  • the annular bulge 30 is hollowed out of a conical annular slot 32 congested downstream, and open at its downstream end 34.
  • the annular slot 32 thus forms a continuous cavity.
  • This annular slot 32 is delimited by an inner wall 38, an outer wall facing the inner wall 38, and a substantially toroidal wall (having the shape of a half-torus whose axis of revolution is the main axis A, and cut in a plane substantially perpendicular to its axis of revolution).
  • the inner and outer walls 38 of the annular slot 32 are substantially parallel and are joined by this substantially toric wall.
  • rectilinear holes 26 distributed around the main axis A open on one side on the substantially toric wall, on the other side on the surface of the annular bulge 30.
  • the holes 26 may to be lights.
  • the axis of each of the holes 26 intersects the main axis A.
  • the holes 26 are not located in the extension of the annular slot 32, that is to say that the axis of each of these holes is not parallel with the generatrix of the cone defining the annular slot 32.
  • the axis of each of the holes 26 is with the main axis at an angle strictly greater than the angle that is made with this main axis the generatrix of the cone defining the annular slot 32, so that the air (coming from outside the combustion chamber) coming out of the holes 26 impacts the inner wall 38 of the annular slot 32.
  • the place of impact on the inner wall 38 of the Outgoing air from the holes 26 is typically in the first upstream third of the annular slot 32.
  • the air is redirected along the annular slot 32, and comes out of it homogeneous.
  • the holes 26 have a diameter of between 0.8 and 1.5 mm, so that the air emerging from these holes in the annular slot 32 has a flow rate and a flow velocity which results in a better homogeneity of the hole. air out of the annular slot 32.
  • the number of holes 26 is between 10 and 20.
  • the height of the slot (distance between the inner wall 38 and the outer wall) is between 1.5 and 3 mm.
  • the length of the slot is between 2 to 3 times its height.
  • the figure 4 is a cross section at holes 26 of an expansion ring 20 according to another embodiment of the invention.
  • the holes 26 comprise a circumferential inclination, that is to say that the axis of each of the holes 26 does not intersect the main axis A.
  • the circumferential inclination angle of the holes 26 is between 20 ° and 45 ° (in absolute value), that is to say that the holes 26 thus inclined generate an air flow in the clockwise direction or in the opposite direction of the clockwise direction around the main axis A in the direction of the fuel flow. On the figure 4 this air flow is generated in a clockwise direction.
  • the downstream end of the inner wall 38 of the annular slot 32 and the downstream end of the inner face of the cylindrical wall 22 meet substantially at one point.
  • the annular slot 32 may have a larger radius (i.e., be further away from the main axis A), the annular bulge 30 being outwardly shifted.
  • the downstream end of the inner wall 38 of the annular slot 32 and the downstream end of the inner face of the cylindrical wall 22 do not meet at the downstream face of the radial wall 24, and are joined by a part of this downstream face.
  • parts of the combustion chamber bottom are located immediately downstream of the injector 10 and the expansion ring 20. These include the primary swirler 40, and the venturi 50.
  • the primary swirler 40 is an annular piece coaxial with the injector 10, placed immediately downstream of the expansion ring 20, whose inner diameter is greater than the diameter of the injector 10.
  • This primary swirler 40 is pierced around its circumference of primary holes 42 through which the air enters the area downstream of the injector 10.
  • the primary holes 42 are oriented so that their axes lie in an axial plane with respect to the main axis, with circumferential inclination.
  • the air exiting the primary holes 42 enters the zone downstream of the injector 10 by rotating around the main axis A and forming a swirler or vortex.
  • the air passed through these holes 26 leaves the annular slot 32 while rotating in the same direction or in the opposite direction to the air coming out of the primary holes 42.
  • the angle that the generatrix of the cone defining the annular slot 32 with the main axis A is such that the air passed through the holes 26 and the air passed through the primary holes 42 do not mix, or at least not immediately.
  • venturi 50 which is an annular piece coaxial with the injector 10.
  • the venturi 50 has a radial wall which extends downstream at its inner end by a convergent 52, which is a conical wall that approaches the main axis A downstream.
  • the convergent 52 is extended by a neck 54, then a divergent 56 which flares downstream.
  • the convergent 52 is therefore downstream of the injector 10.
  • the angle that the generatrix of the cone defining the annular slot 32 with the main axis A is equal to or greater than the angle made by the convergent of the venturi with this main axis A, so that the air passing through the holes 26 of the annular slot 32 does not impact the convergent 52.
  • the inclination of the annular slot 32 is therefore dependent on that of the convergent 52 of the venturi.
  • the angle that the generatrix of the cone defining the annular slot 32 with the main axis A is typically between 30 ° and 60 °.
  • the invention has been described in the case of an injection system of a combustion chamber of a turbomachine.
  • the expansion ring according to the invention could be used with any injector on which it can be mounted.

Abstract

The system has an annular expansion ring (20) that is coaxial with a fuel injector, a primary spin that is coaxial with the ring, and a venturi placed downstream of the spin. The ring has an annular slot (32) that is convergent tapered towards downstream and opened towards downstream. An axis of each hole (26) of the slot forms an angle with a main axis (A) such that air releasing the holes impacts a lower wall (38) of the slot near the main axis. The angle is strictly higher than an angle formed by a cone surface defining the slot with the main axis.

Description

La présente invention concerne le domaine des systèmes d'injection de carburant.The present invention relates to the field of fuel injection systems.

L'invention concerne plus particulièrement une bague de dilatation annulaire centrée sur un axe principal et apte à être montée sur un injecteur de carburant coaxial avec cette bague, cette bague présentant des trous répartis autour de cet axe principal, débouchant sur sa face amont, et permettant le passage de l'air vers la zone en aval de cette bague.The invention more particularly relates to an annular expansion ring centered on a main axis and adapted to be mounted on a fuel injector coaxial with this ring, this ring having holes distributed around this main axis, opening on its upstream face, and allowing the passage of air to the area downstream of this ring.

Comme illustré sur la figure 5 qui représente l'état de l'art, le carburant est injecté dans une chambre de combustion 100 (par exemple dans une chambre de combustion d'une turbomachine) par un injecteur 10 qui se situe à l'extrémité de la conduite amenant ce carburant. Cet injecteur 10 est sensiblement cylindrique, et possède une bague de dilatation 220 annulaire par rapport à un axe principal A et qui entoure une partie de l'injecteur 10, cet injecteur étant coaxial avec la bague de dilatation. La bague de dilatation 220 comprend une partie cylindrique 222 axiale dont la surface radialement intérieure est en contact ou proche de la surface extérieure de l'injecteur 10. Le rôle de cette bague de dilatation 220 est de permettre un rattrapage du jeu entre l'injecteur 10 et les éléments du fond de la chambre de combustion, ce jeu étant causé par les contraintes thermiques auxquelles ces pièces sont soumises. Lors de la combustion, il peut se créer sur l'extrémité aval 12 de l'injecteur 10 des dépôts de coke dus à une combustion inadéquate du carburant. Les dépôts de coke sont indésirables car ils dégradent la pulvérisation de carburant par les injecteurs 10.As illustrated on the figure 5 which represents the state of the art, the fuel is injected into a combustion chamber 100 (for example in a combustion chamber of a turbomachine) by an injector 10 which is located at the end of the pipe bringing this fuel . This injector 10 is substantially cylindrical, and has an expansion ring 220 annular with respect to a main axis A and which surrounds a portion of the injector 10, this injector being coaxial with the expansion ring. The expansion ring 220 comprises an axial cylindrical portion 222 whose radially inner surface is in contact with or near the outer surface of the injector 10. The role of this expansion ring 220 is to allow a clearance of the clearance between the injector 10 and the elements of the bottom of the combustion chamber, this game being caused by the thermal stresses to which these parts are subjected. During combustion, it can be created on the downstream end 12 of the injector 10 coke deposits due to improper combustion of the fuel. The coke deposits are undesirable because they degrade the fuel spraying by the injectors 10.

Dans toute la description, on utilise les adjectifs "amont" et "aval" en relation au sens de circulation normal du carburant en sortie de l'injecteur (sauf si précisé autrement), c'est-à-dire de la gauche vers la droite sur la figure 5. Les adjectifs "intérieur" et "extérieur" sont en relation avec la proximité par rapport à l'axe principal A.Throughout the description, the adjectives "upstream" and "downstream" are used in relation to the direction of normal circulation of the fuel at the outlet of the injector (unless specified otherwise), that is to say from the left to the right on the figure 5 . The adjectives "inside" and "outside" are related to the proximity to the main axis A.

Afin d'empêcher ces dépôts de se produire, la bague de dilatation 220 est percée de trous 226 orientés sensiblement axialement (c'est-à-dire dans la direction de l'axe principal A) qui permettent à de l'air de pénétrer axialement dans la zone située en aval de l'injecteur 10. Cet air pénètre donc parallèlement à la paroi latérale circonférentielle de l'injecteur dans la zone en amont de celui-ci et forme une couche ou film d'air autour de l'injecteur, ce qui permet d'empêcher que du coke se dépose sur l'extrémité aval de l'injecteur. Sur la figure 5, ces trous 226 sont percés dans la paroi radiale 224 de la bague de dilatation 220 qui prolonge radialement vers l'extérieur l'extrémité aval de la partie cylindrique 222 de cette bague.In order to prevent these deposits from occurring, the expansion ring 220 is pierced with holes 226 oriented substantially axially (that is, in the direction of the main axis A) which allow air to penetrate. axially in the zone located downstream of the injector 10. This air thus penetrates parallel to the circumferential side wall of the injector in the zone upstream thereof and forms a layer or film of air around the injector, which prevents coke is deposited on the downstream end of the injector. On the figure 5 these holes 226 are drilled in the radial wall 224 of the expansion ring 220 which extends radially outwardly the downstream end of the cylindrical portion 222 of this ring.

Les tests et utilisations en service effectués par la demanderesse montrent cependant qu'un tel film d'air est la source d'inconvénients. En effet, des pièces du fond de chambre de combustion sont situées immédiatement en aval de l'injecteur. Il s'agit notamment de la vrille primaire 40, et du venturi 50. Ainsi, la vrille primaire 40 est une pièce annulaire coaxiale avec l'injecteur 10, placée immédiatement en aval de la bague de dilatation 220, dont le diamètre intérieur est supérieur au diamètre de l'injecteur. Cette vrille primaire 40 est percée tout autour de sa circonférence de trous primaires 42 par lesquels l'air pénètre dans la zone située en aval de l'injecteur 10. Les trous primaires 42 sont orientés de telle sorte que leurs axes se situent dans un plan radial par rapport à l'axe principal, avec une inclinaison circonférentielle. Ainsi, l'air sortant des trous primaires 42 pénètre dans la zone en aval de l'injecteur 10 en tournant autour de l'axe principal A et en formant une vrille ou tourbillon. Immédiatement en aval de la vrille primaire 40 se situe le venturi 50, qui est une pièce annulaire coaxiale avec l'injecteur 10. Le venturi 50 possède une paroi radiale qui se prolonge vers l'aval (à son extrémité intérieure) par un convergent 52, c'est-à-dire une paroi conique qui se rapproche de l'axe principal A vers l'aval. Le convergent 52 se prolonge par un goulot 54, puis un divergent 56 qui s'évase vers l'aval. Le convergent 52 se situe donc en aval de l'injecteur 10, et se situe sensiblement dans le prolongement axial des trous 226 de la bague de dilatation 220.The tests and uses in service performed by the Applicant show however that such an air film is the source of disadvantages. Indeed, parts of the combustion chamber bottom are located immediately downstream of the injector. These include the primary swirler 40, and the venturi 50. Thus, the primary swirler 40 is an annular piece coaxial with the injector 10, placed immediately downstream of the expansion ring 220, whose inner diameter is greater than to the diameter of the injector. This primary swirler 40 is pierced around its circumference with primary holes 42 through which the air enters the zone situated downstream of the injector 10. The primary holes 42 are oriented so that their axes lie in a plane radial with respect to the main axis, with a circumferential inclination. Thus, the air exiting the primary holes 42 enters the zone downstream of the injector 10 by rotating around the main axis A and forming a swirler or vortex. Immediately downstream of the primary swirler 40 is the venturi 50, which is an annular piece coaxial with the injector 10. The venturi 50 has a radial wall which extends downstream (at its inner end) by a convergent 52 , that is to say a conical wall which approaches the main axis A downstream. The convergent 52 is extended by a neck 54, then a divergent 56 which flares downstream. The convergent 52 is therefore downstream of the injector 10, and is located substantially in the axial extension of the holes 226 of the expansion ring 220.

Les tests effectués par la demanderesse ont révélés que l'air issu des trous 226 pénètre dans la zone en aval de l'injecteur 10 (et de la bague 220) en créant des turbulences. La présente invention vise à remédier à ces inconvénients, ou tout au moins à les atténuer.The tests carried out by the Applicant have revealed that the air issuing from the holes 226 enters the zone downstream of the injector 10 (and the ring 220) by creating turbulence. The present invention aims to remedy these drawbacks, or at least to mitigate them.

L'invention vise à proposer une bague de dilatation telle que l'air issu des trous qui y sont percés pénètre dans la zone en aval de l'injecteur de façon homogène, et sans impacter l'extrémité aval de l'injecteur.The invention aims to propose an expansion ring such that the air coming from the holes which are pierced penetrates into the zone downstream of the injector in a homogeneous manner, and without impacting the downstream end of the injector.

Ce but est atteint grâce au fait que la bague de dilatation comporte une fente annulaire conique convergente vers l'aval, ouverte vers l'aval, les trous débouchant dans la partie amont de cette fente, l'axe de chacun de ces trous faisant avec l'axe principal un angle strictement supérieur à l'angle que fait avec cet axe principal la génératrice du cône définissant la fente annulaire, de telle sorte que l'air sortant des trous impacte la paroi intérieure de la fente annulaire qui est la plus proche de l'axe principal.This object is achieved thanks to the fact that the expansion ring comprises a conical annular slot converging downstream, open downstream, the holes opening into the upstream portion of this slot, the axis of each of these holes making with the main axis an angle strictly greater than the angle that makes with this main axis the generatrix of the cone defining the annular slot, such so that the air coming out of the holes impacts the inner wall of the annular slot which is closest to the main axis.

Grâce à ces dispositions, l'air sortant des trous ne pénètre pas directement dans la zone en aval de l'injecteur, mais impacte d'abord la paroi intérieure de la fente annulaire, et est ensuite redirigé le long de la fente annulaire. Ainsi, l'air sort de la fente annulaire de façon homogène (c'est-à-dire que la vitesse de l'air en sortie de la fente annulaire est sensiblement uniforme sur l'orifice de sortie de la fente annulaire, l'écoulement de l'air n'est donc pas turbulent). De plus, l'angle de la fente annulaire avec l'axe principal est tel que l'air sortant de la fente n'impacte pas la surface de l'injecteur. Ainsi, il ne se produit pas de dépôt de coke sur la surface de l'injecteur.Thanks to these arrangements, the air leaving the holes does not penetrate directly into the downstream zone of the injector, but firstly impacts the inner wall of the annular slot, and is then redirected along the annular slot. Thus, the air exits the annular slot in a homogeneous manner (that is to say that the air velocity at the outlet of the annular slot is substantially uniform over the outlet orifice of the annular slot, the air flow is not turbulent). In addition, the angle of the annular slot with the main axis is such that the air exiting the slot does not impact the surface of the injector. Thus, no coke deposit is produced on the surface of the injector.

Avantageusement, la bague de dilatation comprend une partie cylindrique autour de l'axe principal, et une paroi radiale qui prolonge radialement vers l'extérieur l'extrémité aval de cette partie cylindrique, et la fente annulaire débouche vers l'aval à l'endroit ou la partie cylindrique rejoint la paroi radiale.Advantageously, the expansion ring comprises a cylindrical portion around the main axis, and a radial wall which extends radially outwardly the downstream end of this cylindrical portion, and the annular slot opens downstream at the location or the cylindrical portion joins the radial wall.

Avantageusement, les trous de la bague de dilatation ont par rapport à l'axe principal une inclinaison circonférentielle qui confère à l'air qui les traverse un mouvement de rotation autour de l'axe principal.Advantageously, the holes of the expansion ring have a circumferential inclination with respect to the main axis, which gives the air passing through them a rotational movement about the main axis.

Par exemple, cette inclinaison engendre une circulation d'air dans le sens horaire autour de l'axe principal dans le sens de l'écoulement du carburant. Alternativement, cette inclinaison engendre une circulation d'air dans le sens inverse du sens horaire autour de l'axe principal dans le sens de l'écoulement du carburant.For example, this inclination causes an air flow clockwise around the main axis in the direction of the flow of fuel. Alternatively, this inclination generates a flow of air in the opposite direction of the clockwise direction around the main axis in the direction of the flow of the fuel.

L'invention vise également à proposer un système d'injection comportant une bague de dilatation telle que l'air issu des trous de cette bague n'occasionne pas de dépôt de coke sur l'extrémité aval de l'injecteur, et n'occasionne pas de dépôt de coke sur le convergent du venturi, de tels dépôts de coke étant indésirables car ils dégradent la pulvérisation de carburant par les injecteurs.The invention also aims at providing an injection system comprising an expansion ring such that the air coming from the holes of this ring does not cause coke deposition on the downstream end of the injector, and does not cause no deposit of coke on the convergent venturi, such deposits of coke being undesirable because they degrade the fuel spraying by the injectors.

Ce but est atteint grâce au fait que l'air sortant de la fente annulaire n'impacte pas l'extrémité aval de l'injecteur et sort de la fente annulaire dans une direction sensiblement parallèle à la direction d'écoulement de l'air sortant de la vrille primaire, de telle sorte que ces deux flux d'air ne se mélangent pas (ou du moins seulement plus en aval).This goal is achieved by the fact that the air leaving the annular slot does not impact the downstream end of the injector and leaves the annular slot in a direction substantially parallel to the direction of flow of the air exiting the primary swirler, so that these two air flows do not mix (or at least only further downstream).

Grâce à ces dispositions, outre le fait que l'air sorte de la fente annulaire de façon homogène, cet air n'entraîne pas de dépôt de coke sur la surface de l'extrémité de l'injecteur, et cet air ne perturbe pas l'écoulement de l'air sortant de la vrille primaire. Ainsi, il ne se produit pas de dépôt de coke sur le convergent du venturi.Thanks to these arrangements, in addition to the fact that the air leaves the annular slot homogeneously, this air does not cause coke deposit on the surface of the end of the injector, and this air does not disturb the air. flow of air exiting the primary swirler. Thus, there is no deposit of coke on the convergent venturi.

Avantageusement, la génératrice du cône définissant la fente annulaire de la bague de dilatation fait avec l'axe principal un angle égal ou supérieur à l'angle que fait le convergent du venturi avec cet axe principal, de telle sorte que l'air sortant de la fente annulaire n'impacte pas le convergent du venturi.Advantageously, the generatrix of the cone defining the annular slot of the expansion ring is with the main axis an angle equal to or greater than the angle made by the convergent of the venturi with this main axis, so that the air coming out of the the annular slot does not impact the convergent of the venturi.

Ainsi, la probabilité qu'il se forme un dépôt de coke sur le convergent du venturi est encore diminuée.Thus, the probability of forming a coke deposit on the convergent venturi is further diminished.

En conséquence, la chambre de combustion peut fonctionner avec des débits d'injection de carburant plus faibles (limite d'extinction plus basse). Dans le cas d'un avion muni de moteurs (turbomachines) avec de telles chambres de combustion, il y a un meilleur fonctionnement de la chambre de combustion aux faibles vitesses de l'avion.As a result, the combustion chamber can operate with lower fuel injection rates (lower extinction limit). In the case of an aircraft equipped with engines (turbomachines) with such combustion chambers, there is better operation of the combustion chamber at low speeds of the aircraft.

L'invention sera bien comprise et ses avantages apparaîtront mieux, à la lecture de la description détaillée qui suit, d'un mode de réalisation représenté à titre d'exemple non limitatif. La description se réfère aux dessins annexés sur lesquels :

  • la figure 1 est une coupe d'un système d'injection d'une chambre de combustion comportant une bague de dilatation selon l'invention,
  • la figure 2 est une vue en perspective de la bague de dilatation selon l'invention,
  • la figure 3 est une vue en coupe longitudinale de la bague de dilatation selon l'invention,
  • la figure 4 est une coupe transversale d'un autre mode de réalisation de la bague de dilatation selon l'invention,
  • la figure 5 est un système d'injection d'une chambre de combustion comportant une bague de dilatation selon l'état de la technique.
The invention will be better understood and its advantages will appear better on reading the detailed description which follows, of an embodiment shown by way of non-limiting example. The description refers to the accompanying drawings in which:
  • the figure 1 is a section of an injection system of a combustion chamber comprising an expansion ring according to the invention,
  • the figure 2 is a perspective view of the expansion ring according to the invention,
  • the figure 3 is a longitudinal sectional view of the expansion ring according to the invention,
  • the figure 4 is a cross section of another embodiment of the expansion ring according to the invention,
  • the figure 5 is a combustion chamber injection system comprising a dilation ring according to the state of the art.

La figure 1 illustre un système d'injection d'une chambre de combustion 100 de turbomachine. Ce système d'injection est identique à celui représenté sur la figure 5, à l'exception de la bague de dilatation. Le carburant est injecté dans une chambre de combustion 100 (par exemple dans une chambre de combustion d'une turbomachine) par un injecteur 10. Cet injecteur 10 est sensiblement cylindrique, et possède une bague de dilatation 20 annulaire par rapport à un axe principal A et qui entoure une partie de l'injecteur 10, cet injecteur étant coaxial avec la bague de dilatation. La bague de dilatation 20 comporte une partie cylindrique 22 axiale dont la surface radialement intérieure est en contact ou presque de la surface extérieure de l'injecteur 10. La bague de dilatation 20 comporte en amont de la partie cylindrique 22 une collerette 21 conique qui prolonge cette partie cylindrique en s'évasant radialement vers l'amont. La partie cylindrique 22 et la collerette 21 ont une épaisseur sensiblement constante. La surface intérieure de la partie cylindrique 22 longe l'injecteur 10 jusqu'à l'extrémité aval 12 de cet injecteur, c'est-à-dire l'extrémité de l'injecteur 10 d'où le carburant est injecté vers la chambre de combustion 100 située en aval de l'injecteur. L'extrémité aval de la partie cylindrique 22 de la bague de dilatation 20 est soit légèrement en amont soit aligné avec l'extrémité aval 12 de l'injecteur 10.The figure 1 illustrates a system for injecting a combustion chamber 100 of a turbomachine. This injection system is identical to that shown on the figure 5 , except for the expansion ring. The fuel is injected into a combustion chamber 100 (for example in a combustion chamber of a turbomachine) by an injector 10. This injector 10 is substantially cylindrical, and has an annular expansion ring 20 with respect to a main axis A. and which surrounds a portion of the injector 10, this injector being coaxial with the expansion ring. The expansion ring 20 has a cylindrical portion 22 axial whose radially inner surface is in contact or almost the outer surface of the injector 10. The expansion ring 20 comprises upstream of the cylindrical portion 22 a conical collar 21 which extends this cylindrical portion flaring radially upstream. The cylindrical portion 22 and the flange 21 have a substantially constant thickness. The inner surface of the cylindrical portion 22 along the injector 10 to the downstream end 12 of this injector, that is to say the end of the injector 10 where the fuel is injected to the chamber combustion 100 located downstream of the injector. The downstream end of the cylindrical portion 22 of the expansion ring 20 is either slightly upstream or aligned with the downstream end 12 of the injector 10.

L'extrémité aval de la partie cylindrique 22 se prolonge radialement vers l'extérieur par une paroi radiale 24, de telle sorte que la face intérieure de la partie cylindrique 22 et la face aval de la paroi radiale 24 forment sensiblement un angle droit. La paroi radiale 24 a une épaisseur sensiblement constante. Du côté amont de la paroi radiale 24, à l'endroit où cette paroi radiale rejoint la partie cylindrique 22, la bague de dilatation 20 comporte un renflement annulaire 30 ayant sensiblement la forme d'un tore. Ainsi, la face amont de la paroi radiale 24 se prolonge vers l'amont par la surface du renflement annulaire 30, cette surface rejoignant la face extérieure de la partie cylindrique 22. Ainsi, en coupe longitudinale comme illustré sur la figure 1, la ligne de la face amont de la paroi radiale 24 est perpendiculaire à l'axe principal A, et se prolonge à angle droit vers l'amont par la ligne de la surface du renflement annulaire 30, cette ligne suivant sensiblement un quart de cercle jusqu'à la ligne de la face extérieure de la partie cylindrique 22. La ligne de la surface du renflement annulaire 30 rejoint la ligne de la face extérieure de la partie cylindrique 22 en formant un angle droit. Selon les modes de réalisations, les transitions entre la surface du renflement annulaire 30 et la face amont de la paroi radiale 24 ou la face extérieure de la partie cylindrique 22 peuvent également se faire avec un arrondi.The downstream end of the cylindrical portion 22 is extended radially outwardly by a radial wall 24, so that the inner face of the cylindrical portion 22 and the downstream face of the radial wall 24 form substantially a right angle. The radial wall 24 has a substantially constant thickness. On the upstream side of the radial wall 24, where this radial wall meets the cylindrical portion 22, the expansion ring 20 has an annular bulge 30 having substantially the shape of a torus. Thus, the upstream face of the radial wall 24 is extended upstream by the surface of the annular bulge 30, this surface joining the outer face of the cylindrical portion 22. Thus, in longitudinal section as shown in FIG. figure 1 the line of the upstream face of the radial wall 24 is perpendicular to the main axis A, and extends at right angles upstream by the line of the surface of the annular bulge 30, this line substantially following a quarter circle to the line of the outer face of the cylindrical portion 22. The line of the surface of the annular bulge 30 joins the line of the outer face of the cylindrical portion 22 forming a right angle. According to the embodiments, the transitions between the surface of the annular bulge 30 and the upstream face of the radial wall 24 or the outer face of the cylindrical portion 22 can also be done with a rounding.

Les figures 2 et 3 détaillent la structure de la bague de dilatation 20. Le renflement annulaire 30 est creusé d'une fente annulaire 32 conique convergente vers l'aval, et ouverte à son extrémité aval 34. La fente annulaire 32 forme donc une cavité continue. Cette fente annulaire 32 est délimitée par une paroi intérieure 38, une paroi extérieure en regard de la paroi intérieure 38, et une paroi sensiblement torique (ayant la forme d'un demi-tore ayant pour axe de révolution l'axe principal A, et coupé selon un plan sensiblement perpendiculaire à son axe de révolution). Les parois intérieure 38 et extérieure de la fente annulaire 32 sont sensiblement parallèles et sont jointes par cette paroi sensiblement torique.The Figures 2 and 3 detail the structure of the expansion ring 20. The annular bulge 30 is hollowed out of a conical annular slot 32 congested downstream, and open at its downstream end 34. The annular slot 32 thus forms a continuous cavity. This annular slot 32 is delimited by an inner wall 38, an outer wall facing the inner wall 38, and a substantially toroidal wall (having the shape of a half-torus whose axis of revolution is the main axis A, and cut in a plane substantially perpendicular to its axis of revolution). The inner and outer walls 38 of the annular slot 32 are substantially parallel and are joined by this substantially toric wall.

Dans la partie amont de la fente annulaire 32, des trous 26 rectilignes répartis autour de l'axe principal A débouchent d'un côté sur la paroi sensiblement torique, de l'autre côté sur la surface du renflement annulaire 30. Les trous 26 peuvent être des lumières.In the upstream portion of the annular slot 32, rectilinear holes 26 distributed around the main axis A open on one side on the substantially toric wall, on the other side on the surface of the annular bulge 30. The holes 26 may to be lights.

L'axe de chacun des trous 26 coupe l'axe principal A. Les trous 26 ne sont pas situés dans le prolongement de la fente annulaire 32, c'est à dire que l'axe de chacun de ces trous n'est pas parallèle avec la génératrice du cône définissant la fente annulaire 32. De plus l'axe de chacun des trous 26 fait avec l'axe principal A un angle strictement supérieur à l'angle que fait avec cet axe principal la génératrice du cône définissant la fente annulaire 32, de telle sorte que l'air (qui vient de l'extérieur de la chambre de combustion) sortant des trous 26 impacte la paroi intérieure 38 de la fente annulaire 32. Le lieu d'impact sur la paroi intérieure 38 de l'air sortant des trous 26 est typiquement dans le premier tiers amont de la fente annulaire 32. Ainsi, après son impact sur la paroi intérieure 38, l'air est redirigé le long de la fente annulaire 32, et sort de celle-ci de façon homogène.The axis of each of the holes 26 intersects the main axis A. The holes 26 are not located in the extension of the annular slot 32, that is to say that the axis of each of these holes is not parallel with the generatrix of the cone defining the annular slot 32. In addition the axis of each of the holes 26 is with the main axis at an angle strictly greater than the angle that is made with this main axis the generatrix of the cone defining the annular slot 32, so that the air (coming from outside the combustion chamber) coming out of the holes 26 impacts the inner wall 38 of the annular slot 32. The place of impact on the inner wall 38 of the Outgoing air from the holes 26 is typically in the first upstream third of the annular slot 32. Thus, after its impact on the inner wall 38, the air is redirected along the annular slot 32, and comes out of it homogeneous.

Typiquement, les trous 26 ont un diamètre compris entre 0.8 et 1.5 mm, de façon à ce que l'air émergeant de ces trous dans la fente annulaire 32 ait un débit et une vitesse d'écoulement qui ait pour conséquence une meilleure homogénéité de l'air en sortie de la fente annulaire 32.Typically, the holes 26 have a diameter of between 0.8 and 1.5 mm, so that the air emerging from these holes in the annular slot 32 has a flow rate and a flow velocity which results in a better homogeneity of the hole. air out of the annular slot 32.

Typiquement, le nombre des trous 26 est compris entre 10 et 20.Typically, the number of holes 26 is between 10 and 20.

Typiquement, la hauteur de la fente (distance entre la paroi intérieure 38 et la paroi extérieure) est comprise entre 1,5 et 3 mm. La longueur de la fente est comprise entre 2 à 3 fois sa hauteur.Typically, the height of the slot (distance between the inner wall 38 and the outer wall) is between 1.5 and 3 mm. The length of the slot is between 2 to 3 times its height.

De par la position alignée ou légèrement en retrait de la bague de dilatation 20 par rapport à l'extrémité 12 de l'injecteur 10, l'air n'impacte pas cette extrémité 12, ce qui évite les dépôts de coke sur celle-ci.Due to the aligned or slightly recessed position of the expansion ring 20 relative to the end 12 of the injector 10, the air does not impact this end 12, which avoids the coke deposits thereon .

La figure 4 est une coupe transversale au niveau de trous 26 d'une bague de dilatation 20 selon un autre mode de réalisation de l'invention. Les trous 26 comportent une inclinaison circonférentielle, c'est-à-dire que l'axe de chacun des trous 26 ne coupe pas l'axe principal A. Typiquement, l'angle d'inclinaison circonférentielle des trous 26 est compris entre 20° et 45° (en valeur absolue), c'est-à-dire que les trous 26 ainsi inclinés engendrent une circulation d'air dans le sens horaire ou dans le sens inverse du sens horaire autour de l'axe principal A dans le sens de l'écoulement du carburant. Sur la figure 4, cette circulation d'air est engendrée dans le sens horaire.The figure 4 is a cross section at holes 26 of an expansion ring 20 according to another embodiment of the invention. The holes 26 comprise a circumferential inclination, that is to say that the axis of each of the holes 26 does not intersect the main axis A. Typically, the circumferential inclination angle of the holes 26 is between 20 ° and 45 ° (in absolute value), that is to say that the holes 26 thus inclined generate an air flow in the clockwise direction or in the opposite direction of the clockwise direction around the main axis A in the direction of the fuel flow. On the figure 4 this air flow is generated in a clockwise direction.

Sur les figures 1 à 4, l'extrémité aval de la paroi intérieure 38 de la fente annulaire 32 et l'extrémité aval de la face intérieure de la paroi cylindrique 22 se rejoignent sensiblement en un point. Alternativement, la fente annulaire 32 peut avoir un rayon plus grand (c'est-à-dire être plus éloignée de l'axe principal A), le renflement annulaire 30 étant décalé vers l'extérieur. Dans ce cas, l'extrémité aval de la paroi intérieure 38 de la fente annulaire 32 et l'extrémité aval de la face intérieure de la paroi cylindrique 22 ne se rejoignent pas au niveau de la face aval de la paroi radiale 24, et sont jointes par une partie de cette face aval.On the Figures 1 to 4 , the downstream end of the inner wall 38 of the annular slot 32 and the downstream end of the inner face of the cylindrical wall 22 meet substantially at one point. Alternatively, the annular slot 32 may have a larger radius (i.e., be further away from the main axis A), the annular bulge 30 being outwardly shifted. In this case, the downstream end of the inner wall 38 of the annular slot 32 and the downstream end of the inner face of the cylindrical wall 22 do not meet at the downstream face of the radial wall 24, and are joined by a part of this downstream face.

Comme illustré sur la figure 1, des pièces du fond de chambre de combustion sont situées immédiatement en aval de l'injecteur 10 et de la bague de dilatation 20. Il s'agit notamment de la vrille primaire 40, et du venturi 50. Ainsi, la vrille primaire 40 est une pièce annulaire coaxiale avec l'injecteur 10, placée immédiatement en aval de la bague de dilatation 20, dont le diamètre intérieur est supérieur au diamètre de l'injecteur 10. Cette vrille primaire 40 est percée tout autour de sa circonférence de trous primaires 42 par lesquels l'air pénètre dans la zone située en aval de l'injecteur 10. Les trous primaires 42 sont orientés de telle sorte que leurs axes se situent dans un plan axial par rapport à l'axe principal, avec une inclinaison circonférentielle. Ainsi, l'air sortant des trous primaires 42 pénètre dans la zone en aval de l'injecteur 10 en tournant autour de l'axe principal A et en formant une vrille ou tourbillon. Selon l'inclinaison circonférentielle des trous 26 de la fente annulaire 32, l'air passé par ces trous 26 sort de la fente annulaire 32 en tournant dans le même sens ou dans le sens inverse de l'air sortant des trous primaires 42. Afin de ne pas créer de turbulences, il est préférable que l'air sorte de la fente annulaire 32 en tournant dans le même sens que l'air sortant des trous primaires 42.As illustrated on the figure 1 , parts of the combustion chamber bottom are located immediately downstream of the injector 10 and the expansion ring 20. These include the primary swirler 40, and the venturi 50. Thus, the primary swirler 40 is an annular piece coaxial with the injector 10, placed immediately downstream of the expansion ring 20, whose inner diameter is greater than the diameter of the injector 10. This primary swirler 40 is pierced around its circumference of primary holes 42 through which the air enters the area downstream of the injector 10. The primary holes 42 are oriented so that their axes lie in an axial plane with respect to the main axis, with circumferential inclination. Thus, the air exiting the primary holes 42 enters the zone downstream of the injector 10 by rotating around the main axis A and forming a swirler or vortex. According to the circumferential inclination of the holes 26 of the annular slot 32, the air passed through these holes 26 leaves the annular slot 32 while rotating in the same direction or in the opposite direction to the air coming out of the primary holes 42. not to create turbulence, it is preferable that the air comes out of the annular slot 32 by rotating in the same direction as the air coming out of the primary holes 42.

Dans tous les cas (inclinaison circonférentielle nulle ou non des trous 26 de la fente annulaire), l'angle que fait la génératrice du cône définissant la fente annulaire 32 avec l'axe principal A est tel que l'air passé par les trous 26 et l'air passé par les trous primaires 42 ne se mélangent pas, ou du moins pas tout de suite.In all cases (circumferential inclination or no holes 26 of the annular slot), the angle that the generatrix of the cone defining the annular slot 32 with the main axis A is such that the air passed through the holes 26 and the air passed through the primary holes 42 do not mix, or at least not immediately.

Immédiatement en aval de la vrille primaire 40 se situe le venturi 50, qui est une pièce annulaire coaxiale avec l'injecteur 10. Le venturi 50 possède une paroi radiale qui se prolonge vers l'aval à son extrémité intérieure par un convergent 52, qui est une paroi conique qui se rapproche de l'axe principal A vers l'aval. Le convergent 52 se prolonge par un goulot 54, puis un divergent 56 qui s'évase vers l'aval. Le convergent 52 se situe donc en aval de l'injecteur 10. L'angle que fait la génératrice du cône définissant la fente annulaire 32 avec l'axe principal A est égal ou supérieur à l'angle que fait le convergent du venturi avec cet axe principal A, de telle sorte que l'air passé par les trous 26 de la fente annulaire 32 n'impacte pas le convergent 52. Ainsi, il ne se produit pas de dépôt de coke sur le convergent du venturi. En effet, puisqu'il n'y a pas d'impact d'air (éventuellement mélangé à du carburant) directement sur le convergent 52, il ne se produit pas de turbulence à proximité de la surface de ce convergent, donc pas de zone morte où l'air a une vitesse nulle, et donc pas de formation de coke sur la surface du convergent 52.Immediately downstream of the primary swirler 40 is the venturi 50, which is an annular piece coaxial with the injector 10. The venturi 50 has a radial wall which extends downstream at its inner end by a convergent 52, which is a conical wall that approaches the main axis A downstream. The convergent 52 is extended by a neck 54, then a divergent 56 which flares downstream. The convergent 52 is therefore downstream of the injector 10. The angle that the generatrix of the cone defining the annular slot 32 with the main axis A is equal to or greater than the angle made by the convergent of the venturi with this main axis A, so that the air passing through the holes 26 of the annular slot 32 does not impact the convergent 52. Thus, there is no deposit of coke on the convergent venturi. Indeed, since there is no air impact (possibly mixed with fuel) directly on the convergent 52, there is no turbulence near the surface of this convergent, so no zone dead where the air has zero velocity, and therefore no coke formation on the surface of convergent 52.

L'inclinaison de la fente annulaire 32 est donc tributaire de celle du convergent 52 du venturi. L'angle que fait la génératrice du cône définissant la fente annulaire 32 avec l'axe principal A est typiquement compris entre 30° et 60°.The inclination of the annular slot 32 is therefore dependent on that of the convergent 52 of the venturi. The angle that the generatrix of the cone defining the annular slot 32 with the main axis A is typically between 30 ° and 60 °.

L'invention a été décrite dans le cas d'un système d'injection d'une chambre de combustion d'une turbomachine. Cependant la bague de dilatation selon l'invention pourrait être utilisée avec n'importe quel injecteur sur lequel elle peut être montée.The invention has been described in the case of an injection system of a combustion chamber of a turbomachine. However, the expansion ring according to the invention could be used with any injector on which it can be mounted.

Claims (12)

Système d'injection comportant un injecteur (10) de carburant d'axe principal (A), une bague de dilatation (20) annulaire coaxiale avec ledit injecteur (10), une vrille primaire (40) coaxiale avec ladite bague, placée en aval dudit injecteur, et un venturi (50) placé en aval de ladite vrille primaire, ladite bague présentant des trous (26) répartis autour de cet axe principal, débouchant sur la face amont de ladite bague (20), et permettant le passage de l'air vers la zone en aval de ladite bague (20), caractérisée en ce que ladite bague comporte une fente annulaire (32) conique convergente vers l'aval, ouverte vers l'aval, lesdits trous débouchant dans la partie amont de ladite fente (32), l'axe de chacun de ces trous (26) faisant avec l'axe principal (A) un angle strictement supérieur à l'angle que fait avec cet axe principal la génératrice du cône définissant ladite fente annulaire (32), de telle sorte que l'air sortant desdits trous (26) impacte la paroi intérieure (38) de la fente annulaire qui est la plus proche de l'axe principal.Injection system comprising a main axis fuel injector (10) (A), an annular expansion ring (20) coaxial with said injector (10), a primary swirler (40) coaxial with said ring, downstream said injector, and a venturi (50) placed downstream of said primary swirler, said ring having holes (26) distributed around this main axis, opening on the upstream face of said ring (20), and allowing the passage of the air towards the zone downstream of said ring (20), characterized in that said ring comprises an annular conical slot (32) convergent downstream, open downstream, said holes opening into the upstream portion of said slot (32), the axis of each of these holes (26) making with the main axis (A) an angle strictly greater than the angle that makes with this main axis the generatrix of the cone defining said annular slot (32), such that the air issuing from said holes (26) impacts the inner wall (38) of the annular slot which is closest to the main axis. Système d'injection selon la revendication 1, caractérisé en ce que ladite bague de dilatation (20) comprend une partie cylindrique (22) autour dudit axe principal (A), et une paroi radiale (24) qui prolonge radialement vers l'extérieur l'extrémité aval de cette partie cylindrique, et en ce que ladite fente annulaire (32) débouche vers l'aval à l'endroit ou ladite partie cylindrique (22) rejoint ladite paroi radiale (24).Injection system according to claim 1, characterized in that said expansion ring (20) comprises a cylindrical part (22) around said main axis (A), and a radial wall (24) which extends radially outwardly. the downstream end of this cylindrical portion, and in that said annular slot (32) opens downstream at the location where said cylindrical portion (22) joins said radial wall (24). Système d'injection selon la revendication 1 ou 2, caractérisé en ce que lesdits trous (26) ont par rapport audit axe principal (A) une inclinaison circonférentielle qui confère à l'air qui les traverse un mouvement de rotation autour de l'axe principal.Injection system according to claim 1 or 2, characterized in that said holes (26) have a circumferential inclination with respect to said main axis (A) which gives the air passing therethrough a rotational movement about the axis main. Système d'injection selon la revendication 3, caractérisé en ce que l'angle d'inclinaison circonférentielle desdits trous (26) est compris entre 20° et 45° par rapport à une direction radiale.Injection system according to claim 3, characterized in that the circumferential inclination angle of said holes (26) is between 20 ° and 45 ° with respect to a radial direction. Système d'injection selon l'une quelconque des revendications 1 à 4, caractérisé en ce que lesdits trous (26) ont un diamètre compris entre 0.8 et 1.5 mm.Injection system according to any one of claims 1 to 4, characterized in that said holes (26) have a diameter of between 0.8 and 1.5 mm. Système d'injection selon l'une quelconque des revendications 1 à 5, caractérisé en ce que le nombre desdits trous (26) est compris entre 10 et 20.Injection system according to any one of claims 1 to 5, characterized in that the number of said holes (26) is between 10 and 20. Système d'injection selon l'une quelconque des revendications 1 à 6, caractérisé en ce que la hauteur de ladite fente annulaire (32) est comprise entre 1,5 et 3 mm.Injection system according to any one of claims 1 to 6, characterized in that the height of said annular slot (32) is between 1.5 and 3 mm. Système d'injection selon l'une quelconque des revendications 1 à 7, caractérisé en ce que le lieu d'impact de l'air sortant desdits trous (26) de la bague sur la paroi intérieure (38) de la fente annulaire (32) se situe dans le premier tiers amont de la fente annulaire.Injection system according to any one of claims 1 to 7, characterized in that the place of impact of the air issuing from said holes (26) of the ring on the inner wall (38) of the annular slot (32) ) is in the first third upstream of the annular slot. Système d'injection selon l'une quelconque des revendications 1 à 8, caractérisé en ce que ladite vrille primaire (40) possède des trous primaires (42) par lesquels l'air pénètre dans la zone située en aval dudit injecteur, et en ce que l'air sort de la fente annulaire (32) dans une direction sensiblement parallèle à la direction d'écoulement de l'air sortant de la vrille primaire, de telle sorte que ces deux flux d'air ne se mélangent pas.Injection system according to any one of claims 1 to 8, characterized in that said primary swirler (40) has primary holes (42) through which the air enters the area downstream of said injector, and in that that the air exits the annular slot (32) in a direction substantially parallel to the direction of flow of the air exiting the primary swirler, so that these two air streams do not mix. Système d'injection selon l'une quelconque des revendications 1 à 9, caractérisé en ce que ledit venturi (50) possède un convergent (52) qui converge vers l'aval, et en ce que la génératrice du cône définissant ladite fente annulaire (32) fait avec ledit axe principal (A) un angle égal ou supérieur à l'angle que fait ledit convergent (52) du venturi avec cet axe principal, de telle sorte que l'air sortant de ladite fente annulaire (32) n'impacte pas le convergent du venturi.Injection system according to any one of claims 1 to 9, characterized in that said venturi (50) has a convergent (52) which converges downstream, and in that the generatrix of the cone defining said annular slot ( 32) makes with said main axis (A) an angle equal to or greater than the angle that said convergent (52) of the venturi makes with this main axis, so that the air issuing from said annular slot (32) does not does not impact the convergent of the venturi. Chambre de combustion munie d'un système d'injection selon l'une quelconque des revendications 1 à 10.Combustion chamber provided with an injection system according to any one of claims 1 to 10. Turbomachine comportant une chambre de combustion selon la revendication 11.Turbomachine comprising a combustion chamber according to claim 11.
EP08159886A 2007-07-12 2008-07-08 Optimisation of an anti-coke film in an injection system Active EP2014988B1 (en)

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FR0756450A FR2918716B1 (en) 2007-07-12 2007-07-12 OPTIMIZATION OF ANTI-COKE FILM IN AN INJECTION SYSTEM

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EP2014988A1 true EP2014988A1 (en) 2009-01-14
EP2014988B1 EP2014988B1 (en) 2012-11-21

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EP3309458A1 (en) * 2016-10-13 2018-04-18 Rolls-Royce plc A combustion chamber and a combustion chamber fuel injector seal
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CN107796016A (en) * 2017-09-29 2018-03-13 哈尔滨理工大学 A kind of gas-turbine combustion chamber double fuel integrated spray nozzle device

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RU2008128382A (en) 2010-01-20
US8276388B2 (en) 2012-10-02
US20090049840A1 (en) 2009-02-26
CA2636923A1 (en) 2009-01-12
RU2478876C2 (en) 2013-04-10
FR2918716A1 (en) 2009-01-16
CA2636923C (en) 2015-08-25
EP2014988B1 (en) 2012-11-21
FR2918716B1 (en) 2014-02-28

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