INJECTION SYSTEM FOR AN ANNULAR COMBUSTION CHAMBER OF AN AIRCRAFT TURBOMACHINE

Abstract

The invention relates to an injection system (19) for an annular combustion chamber of an aircraft turbomachine, this system comprising: - an annular member (19a) an annular collar (25); - an annular sleeve (30) extending around said axis (C) and comprising a radial annular wall (31) the external periphery of which is connected to a cylindrical annular wall (32) which surrounds said collar (25), and - a ring (40) attached and fixed on the sleeve (30). According to the invention, the collar (25) comprises male (50) or female (60) elements engaged in female (60) or male (50) elements of complementary shapes to the radial annular wall (31) of the sheath (30), these male (50) and female (60) elements being surrounded by the cylindrical annular wall (32) of the sheath (30) which extends continuously over 360°. Figure for the abbreviation: Figure 5

Description

Title of the invention: INJECTION SYSTEM FOR AN ANNULAR COMBUSTION CHAMBER OF AN AIRCRAFT TURBOMACHINE Technical field of the invention

[0001] The present invention relates to an injection system for an annular combustion chamber of an aircraft turbomachine. Technical background

[0002] Applications FR-A1-2 918 716, FR-A1-2 925 146, FR-A1-2 941 288, and FR-A1-2 975 467 describe turbomachine injection systems.

[0003] A turbomachine includes a gas generator comprising in particular one or more compressors, for example low pressure and high pressure, arranged upstream of a combustion chamber.

[0004] By convention, in this application, the terms "upstream" and "downstream" are defined with respect to the direction of gas flow in the turbomachine. Similarly, by convention in this application, the terms "internal" and "external" are defined radially with respect to the longitudinal axis of the turbomachine, which is in particular the axis of rotation of the compressor rotors.

[0005] Traditionally, the combustion chamber is annular and placed in an annular enclosure radially delimited by an outer annular casing and an inner annular casing. The combustion chamber is delimited by coaxial inner and outer annular walls joined upstream by a chamber bottom, also annular, and substantially transverse.

[0006] The combustion chamber is supplied in particular with compressed air from, for example, a high-pressure compressor located upstream of the combustion chamber via, in particular, an annular diffuser, and with fuel via injection systems distributed angularly around the axis of revolution of the chamber.

[0007] A conventional injection system includes an annular support and centering element for an injector head. The element comprises augers that deliver airflows downstream of the injector to create an air-fuel mixture for injection and subsequent combustion in the combustion chamber. A frustoconical mixing bowl can be mounted downstream of the augers for atomizing the air / fuel mixture entering the combustion chamber.

[0008] The injector head support and centering member has a central orifice with an axis adapted to receive the injector head. The member may have a frustoconical surface that is flared upstream and connected at its downstream end, which is Therefore, the one with the smallest diameter is at the upstream end of a cylindrical surface. The injector head is then able to cooperate by sliding with the frustoconical surface to center the injector, and then with the cylindrical surface.

[0009] The annular element slides between a sleeve and a ring attached to the sleeve, which provides a certain degree of axial freedom for the element within the sleeve and therefore for the injector head relative to the injection system. However, during operation, the tangential component due to aerodynamic stress in spins causes the annular element to rotate about its own axis, hence the need to prevent its rotation.

[0010] In the current technique, the rotational locking of the component is ensured by a tab of the component which bears against a stop on the sleeve. However, repeated contact between these elements causes wear on the tab and the sleeve, eventually necessitating the replacement of the injection system and the sleeve. Furthermore, since the sleeve is brazed to the bottom of the chamber, replacing it requires a complex and expensive operation.

[0011] The objective of the present invention is to provide a simple, effective and economical solution to at least one of the aforementioned problems. Summary of the invention

[0012] The invention relates to an injection system for an annular combustion chamber of an aircraft turbomachine, this system comprising:

[0013] - an annular organ comprising: • a central shaft opening suitable for receiving a fuel injector head, • at least one annular tendril extending around said axis, and • an annular collar that extends radially outwards from said axis,

[0014] - an annular sheath extending around said axis and comprising an annular wall radial, the outer periphery of which is connected to a cylindrical annular wall that surrounds said collar, and

[0015] - a ring attached and fixed to the sheath, this ring extending around said axis and comprising a radial annular wall, said radial annular walls delimiting between them an annular space for housing and sliding of said collar.

[0016] According to the invention, the collar comprises male or female elements engaged in female or male elements of complementary shapes of the radial annular wall of the sheath, these male and female elements being surrounded by the cylindrical annular wall of the sheath which extends continuously over 360°.

[0017] The invention thus provides for eliminating the tab of the prior art and replacing it with a system of form(s) (male or female elements respectively, on the collar of the injection system) and counter-form(s) (female or male elements respectively, at the level of the sleeve). This solution makes it possible, in particular, to move from linear contact (between the tab and the sleeve) to surface contact (between the form and its counter-form) and therefore to multiply the contact points in the injection system. Increasing the contact points in this configuration makes it possible, in particular, to reduce wear on the injection system and considerably increase its service life. The invention thus makes it possible, in particular, to overcome premature wear of the injection system while maintaining the anti-rotation function of the injection system component.

[0018] The invention makes it possible to achieve these objectives without thickening certain areas of the injection system and without modifying its positioning, which in particular avoids impacting the performance of the annular combustion chamber, especially during reignition. Furthermore, the internal and external diameters of the sleeve remain unchanged, which notably avoids impacting the cooling of the chamber bottom and does not reduce the movement of the component within its sleeve.

[0019] The system according to the invention may comprise one or more of the following features, taken individually or in combination with each other:

[0020] - the male elements, or respectively female elements, are at least two in number, preferably at least three of them, and for example at least four of them;

[0021] - the male, or respectively female, elements are regularly distributed around said axis;

[0022] - the male, or respectively female, elements are located on, or formed by, a peripheral contour of the collar;

[0023] - the peripheral contour of the collar has a general shape chosen from a sign plus and a square or triangular geometric shape;

[0024] - the peripheral contour of the collar comprises straight and curved edges and is devoid of any protruding angle;

[0025] - the male or, respectively, female elements each have an angular extent around the axis between 30 and 70°;

[0026] - the male, or respectively female, elements of the collar are located on a radial annular face of the collar and face the radial annular wall of the sheath;

[0027] - the male or, respectively, female elements each have an angular extent around the axis between 10 and 30°;

[0028] - the female, or respectively male, elements of the radial annular wall of the sheaths are formed by a variation in axial thickness of this wall;

[0029] - the male, or respectively female, elements of the collar are engaged with play in the female, or respectively male, elements of the radial annular wall of the sheath, this play being located in a plane perpendicular to the axis;

[0030] - the male, or respectively female, elements of the collar and the elements females, or respectively males, of the radial annular wall have the same axial thickness;

[0031] - the collar is inscribed in a circle which has a first diameter less than one second internal diameter of the cylindrical annular wall of the sheath;

[0032] - the difference between the first and second diameters is greater than or equal to one radial thickness of the cylindrical annular wall of the sheath;

[0033] The invention also relates to an aircraft turbomachine, comprising a combustion chamber equipped with at least one injection system as described above. Brief description of the figures

[0034] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which:

[0035] [Fig-1] [Fig.1] is a detail view of a longitudinal half-section of a turbomachine illustrating in particular a combustion chamber of the turbomachine, this turbomachine being equipped with an injection system;

[0036] [Fig.2] [Fig.2] is an axial cross-sectional view of the injection system of [Fig.1];

[0037] [Fig.3] [Fig.3] is an exploded perspective view of the injection system according to a first embodiment viewed from downstream to upstream;

[0038] [Fig.4] [Fig.4] is an exploded perspective view of the injection system of [Fig.3] seen from upstream to downstream;

[0039] [Fig.5] [Fig.5] is an exploded perspective view of the injection system according to a second embodiment;

[0040] [Fig. 6] [Fig. 6] is a perspective view of the injection system 2 according to a third embodiment; and

[0041] [Fig.7] [Fig.7] is a perspective view of the injection system according to a fourth embodiment. Detailed description of the invention

[0042] Figure 1 shows an annular combustion chamber 1 of a gas generator of an aircraft turbomachine.

[0043] The combustion chamber 1 is placed downstream of one or more compressors, for example low pressure and high pressure, and upstream of one or more turbines, for example high pressure and low pressure.

[0044] The combustion chamber 1 is part of a turbomachine having a longitudinal X axis which is in particular the axis of rotation of the rotors of the compressors and turbines.

[0045] According to the embodiment illustrated in [Fig.1], the combustion chamber 1 is in particular placed downstream of a high-pressure compressor and is, for example, placed here coaxially with the latter.

[0046] More specifically, the chamber 1 is placed in an annular enclosure 5 radially delimited by an external annular housing 6 and an internal annular housing 7. The compressed air flow 8 generated by the compressor enters the enclosure 5 via an annular diffuser 9.

[0047] The combustion chamber 1 is delimited by coaxial internal and external annular walls 11,12 joined upstream by a chamber bottom 13 which is also annular and substantially transverse.

[0048] More specifically, according to the embodiment illustrated in [Fig.1], the chamber 1 is substantially centered radially in the enclosure 5 so as to define on the one hand an internal, annular air passage 14, delimited radially by the internal wall 11 and the internal casing 7, and on the other hand an external, annular air passage 15, delimited radially by the external wall 12 and the external casing 6.

[0049] The chamber 1 is supplied with an air and fuel mixture by several air and fuel injection devices 16 distributed angularly at regular intervals around the X axis. More specifically, each injection device 16 comprises a fuel injector 17 and an air injection system 19.

[0050] The injector 17 is angled and has one end fixed to the outer casing 6 and an opposite end forming a head 18 which is engaged and centered in the injection system 19.

[0051] The injection system 19 is fixed to the bottom 13 and in particular mounted in an orifice 13a of the bottom 13, to allow the air and fuel mixture to be sprayed into the chamber 1.

[0052] The injection system 19 includes means 19a for supporting and centering the injector head 18 17 (for example, an annular member 19a). The annular member 19a includes a central orifice with axis C adapted to receive the injector head 18 17, at least one annular spiral 19b extending around axis C and configured to form the airflow intended to mix with the fuel injected by the injector head 18 17, and an annular flange 25 (visible in Figures 2 to 7) extending radially outward from axis C. The member 19a may also include means 19c for diffusing an air-fuel mixture into the chamber. The injection system 19 further comprises an annular sleeve 30 and a ring 40 (visible in particular in Figures 2 to 5). In the embodiments shown in the figures, the axis C forms an axis of revolution for the injection system 19.

[0053] Chamber 1 is thus supplied with compressed air by the injection system 19, this compressed air being mixed with the fuel supplied by the injectors 17. Chamber 1 is supplied with compressed air, in particular, via so-called "primary" holes 20 (for example, a circumferential row on the inner wall 11 and on the outer wall 12) and via "dilution" holes 21 (for example, a circumferential row on the inner wall 11 and on the outer wall 12) located downstream of the primary holes 20. The primary and dilution holes 20 and 21 are supplied with air via the internal and external air passages 14 and 15.

[0054] Combustion of the air / fuel mixture is initiated via one or more ignition devices 22 fixed to the outer wall 12. According to the illustrated example, the ignition devices 22 are located longitudinally at the primary holes 20.

[0055] In order to cool the internal and external walls 11,12 of the combustion chamber 1, the latter include in particular a plurality of cooling holes, generally inclined, distributed in circumferential rows, so as to achieve cooling commonly referred to as "by multi-perforation".

[0056] As illustrated in figures 2 to 7, the annular organ 19a of each injection system 19 may include a frustoconical surface 23a which is flared upstream and which is connected by its downstream end, which is therefore the one with the smallest diameter, to the upstream end of a cylindrical surface 23b.

[0057] The central orifice with axis C of the annular member 19a can receive the injector head which then cooperates by sliding with the frustoconical surface 23a in particular to center the injector, and then with the cylindrical surface 23b. The injector head is then inserted into the annular member 19a.

[0058] The annular element 19a here comprises two annular spirals 19b. Each of the annular spirals 19b may, in particular, include a stage of vanes 34, 35 whose function is to drive the air in rotation around the longitudinal axis C of the injection system 19. The vanes of the stages 34 and 35 may be in the same or opposite directions. Furthermore, a frustoconical mixing bowl 24 may be mounted downstream of the spirals 19b for atomizing the air / fuel mixture entering the combustion chamber.

[0059] The annular sleeve 30 is fixed to the bottom of chamber 13 of chamber 1, and is for example brazed to the bottom of chamber 13. The annular sleeve 30 extends around the axis C and comprises a radial annular wall 31 whose external periphery is connected to a cylindrical annular wall 32 of the sleeve 30 which surrounds the collar 25 and which extends continuously over 360°.

[0060] The ring 40 is attached and fixed to the sleeve 30, for example by welding, and thus forms a closing ring. The ring 40 extends around the axis C and has a radial annular wall 41 located opposite the radial annular wall 31 of the sleeve 30. The radial annular walls 31, 41 of the sleeve 30 and of the ring 40 are, for example, substantially parallel and define between them an annular space 27 for housing and sliding the collar 25.

[0061] According to the invention, the collar 25 comprises male elements 50, or respectively female elements 60, engaged in female elements 60, or respectively male elements 50, of complementary shapes to the radial annular wall 31 of the sleeve, these male elements 50 and female elements 60 being surrounded by the cylindrical annular wall 32 of the sleeve 30. In the illustrated embodiments, the collar 25 comprises the male elements 50 and the sleeve comprises the female elements 60. The invention thus enables the injection system 19 to include a male form system cooperating with a female counter-form system to prevent the rotation of the collar 25 relative to the sleeve 30 along the axis C.

[0062] The male elements 50 are at least two in number, preferably at least three, and for example at least four. The female elements 60 are in particular the same number as the male elements 50, in particular at least two in number, preferably at least three, and for example at least four.

[0063] The male elements 50, for example, are regularly distributed around the axis C. The female elements 60, are in particular regularly distributed around said axis C.

[0064] The male elements 50 (or respectively female elements 60) are located on, or formed by, a peripheral contour 28 of the collar 25.

[0065] In particular, in the embodiment shown in Figures 3 and 4, the male elements 50 are located on the collar 25.

[0066] The male elements 50 (or respectively female elements 60) of the collar 25 are in particular located on a radial annular face 26 of the collar 25 and face the radial annular wall 31 of the sleeve 30. The male elements 50, or respectively female elements 60, have for example here each an angular extent around the axis C of between 10 and 30°.

[0067] In this embodiment, the male elements 50 have, in particular, the form of a boss 51, specifically parallelepiped in shape, formed from the material along with the collar 25, and are, for example, four in number. They are distributed regularly along the collar 25, for example, approximately every 90°. The male elements 50 project axially from the collar 25 towards the annular radial wall 31 of the sheath 30. The female elements 60 are in the form of notches 61, cut specifically into the sheath 30. particularly in the annular radial wall 31 of the sheath 30. The notches 61 are in particular complementary in shape to the bosses 51 and are for example 4 in number. The notches 61 are in particular distributed on the sheath 30 in a regular manner, for example about every 90°.

[0068] Thus, when the annular member 19a is positioned on the sleeve 30, the male elements 50, here the bosses 51, are engaged in the female elements 60, here the notches 61, so that the member 19a is prevented from rotating about axis C relative to the sleeve 30. This type of cooperation between male elements 50 and female elements 60 is called "gear-like cooperation." The axial depth of the female elements 60, here the notches 61, is substantially equal to that of the male elements 50, here the bosses 51. This makes it possible, in particular, to create surface contact between the radial annular face 26 of the collar 25 and the radial annular wall 31 of the sleeve 30.The contact between the collar 25 and the sleeve 30 is therefore made via the male elements 50 and female elements 60, but also by surface contact between the radial annular face 26 of the collar 25 and the radial annular wall 31 of the sleeve 30, which greatly limits the wear of the various parts of the injection system 19 according to the invention.

[0069] In the embodiment examples of figures 5 to 7, the male elements 50, (or respectively female elements 60), are formed by or on the peripheral contour 28 of the collar 25. The peripheral contour 28 of the collar 25 here has a general shape chosen from a "plus" or "+" sign ([Fig.5]) and a square geometric shape ([Fig.6]) or triangular shape ([Fig.7]).

[0070] In these embodiments, the peripheral contour 28 of the collar 25 comprises straight and curved edges and is devoid of any salient angles. Indeed, in the embodiment shown in [Fig. 6], the peripheral contour 28 of the collar 25 comprises four straight edges forming the four sides of the square shape, and four curved edges forming the four corners of the square shape, but without any salient angles. In the embodiment shown in [Fig. 7], the peripheral contour 28 of the collar 25 comprises three straight edges forming the three sides of the triangular shape, and three curved edges forming the three corners of the triangular shape, but without any salient angles.

[0071] In the embodiments shown in Figures 5 to 7, the male elements 50, or respectively female elements 60, each have an angular range around axis C of between 30° and 70°. The female elements 60 (or respectively male elements 50) of the radial annular wall 31 of the sleeve 30 are formed by a variation in the axial thickness of this wall 31. The radial annular wall 31 thus comprises at least one thin portion 31a with a lower axial thickness, and at least one thick portion 31b with a greater axial thickness. Thus, the thin portion 31a defines the female elements 60 and is configured to receive the The male elements 50 of the collar 25. The thin part(s) 31a are connected to the thick part(s) 31b by an internal rim 33 of the sleeve 30 extending axially. The contact between the collar 25 and the sleeve 30 is therefore made via the internal rim 33 of the sleeve 30 and a peripheral edge 29 of the peripheral contour 28 of the collar 25, but also by surface contact between the radial annular face 26 of the male elements 50 of the collar 25 and the thin part 31a of the annular radial wall 31 of the sleeve 30, which greatly limits wear on the various parts of the injection system 19.

[0072] In the embodiment shown in [Fig. 5], the sheath 30 comprises four thin portions 31a configured to receive the four male elements 50 of the collar 25 in the shape of a "plus" (+), such that each of the four arms of the + shape is received by the four thin portions 31a. The sheath 30 further comprises four thick portions 31b interposed between the four thin portions 31a. In the embodiment shown in [Fig. 6], the sheath 30 comprises a thin portion 31a forming the female elements 60, in the geometric shape of a square, such that the thin portion 31a is configured to receive the male elements 50 of the collar 25 in the geometric shape of a square. The sheath 30 here includes a thick part 31b at the periphery of the thin part 31a and forming the link between the thin part 31a and the cylindrical annular wall 32. In the embodiment example of [Fig.[7] The sheath 30 includes a thin portion 31a forming the female elements 60, in the geometric shape of a triangle, such that the thin portion 31a is configured to accommodate the male elements 50 of the collar 25 in the geometric shape of a triangle. The sheath 30 here includes a thick portion 31b at the periphery of the thin portion 31a and forming the link between the thin portion 31a and the cylindrical annular wall 32.

[0073] In the embodiment examples of figures 5 to 7, the thick parts 31b protrude axially relative to the thin parts 31a over a distance equivalent to the thickness of the collar 25, i.e. that the internal contour(s) 33 are of the same thickness as the collar 25. This makes it possible in particular to create a surface contact between the radial annular face 26 of the collar 25, in particular the radial annular face 26 of the male elements 50 of the collar 25, and the radial annular wall 31 of the sleeve 30, in particular the thin parts 31a of the radial annular wall 31 of the sleeve 30.

[0074] In all embodiments of the invention, the male elements 50, or respectively female elements 60, of the collar 25 and the female elements 60, or respectively male elements 50, of the radial annular wall 31 of the sleeve 30 have in particular the same axial thickness so that the contact between the collar 25 and the sleeve 30 is predominantly surface contact, in particular in a plane perpendicular to the axis C.

[0075] The male elements 50, or respectively female elements 60, of the collar 25 are engaged with clearances J in the female elements 60, or respectively male elements 50, of the radial annular wall 31 of the sleeve 30, these clearances J being located in a plane perpendicular to the axis C. These clearances J allow, in particular, the movement of the annular member 19a in the sleeve 30. This movement facilitates, in particular, the guidance of the annular member 19a in the sleeve 30 without compromising the rotational locking of the member 19a around the axis C relative to the sleeve 30.

[0076] The collar 25 is inscribed in a circle which has a first diameter d (visible in [Fig.5]) in particular less than a second internal diameter D of the cylindrical annular wall 32 of the sleeve 30. The difference between the first d and second D diameters is greater than or equal to a radial thickness E of the cylindrical annular wall 32 of the sleeve 30.

[0077] The invention also relates to an aircraft turbomachine, comprising a combustion chamber 1 equipped with at least one injection system 19 as described.

Claims

Demands

1. Injection system (19) for an annular combustion chamber (1) of an aircraft turbomachine, said system comprising: - an annular member (19a) having: • a central orifice with axis (C) adapted to receive a fuel injector head (18), • at least one annular spiral (19b) extending around said axis (C), and • an annular flange (25) extending radially outwards with respect to said axis (C), - an annular sleeve (30) extending around said axis (C) and having a radial annular wall (31) the outer periphery of which is connected to a cylindrical annular wall (32) surrounding said flange (25), and - a ring (40) attached and fixed to the sleeve (30), this ring (40) extending around said axis (C) and having a radial annular wall (41), said radial annular walls (31, 41) delimiting between them an annular space (27) for housing and sliding of said collar (25),characterized in that the collar (25) comprises male elements (50), or respectively female elements (60), engaged in female elements (60), or respectively male elements (50), of complementary shapes to the radial annular wall (31) of the sheath (30), these male (50) and female (60) elements being surrounded by the cylindrical annular wall (32) of the sheath (30) which extends continuously over 360°.

2. System (19) according to claim 1, wherein the male elements (50), or respectively female elements (60), are at least two in number, preferably at least three, and for example at least four in number.

3. System (19) according to claim 1 or 2, wherein the male elements (50), or respectively female elements (60), are regularly distributed around said axis (C).

4. System (19) according to any one of the preceding claims, wherein the male elements (50), or respectively female elements (60), are located on, or formed by, a peripheral contour (28) of the collar (25).

5. System (19) according to the preceding claim, wherein the peripheral contour (28) of the collar (25) has a general shape selected from a plus sign and a square or triangular geometric shape.

6. System (19) according to claim 4 or 5, wherein the peripheral contour (28) of the collar (25) comprises straight and curved edges and is devoid of salient angle.

7. System according to any one of claims 4 to 6, wherein the male elements (50), or respectively female elements (60), each have an angular range around the axis (C) between 30 and 70°.

8. System (19) according to any one of claims 1 to 3, wherein the male elements (50), or respectively female elements (60), of the collar (25) are located on a radial annular face (26) of the collar (25) and face the radial annular wall (31) of the sheath (30).

9. System according to claim 8, wherein the male elements (50), or respectively female elements (60), each have an angular range around the axis (C) of between 10 and 30°.

10. System (19) according to any one of the preceding claims, wherein the female elements (60), or respectively male elements (50), of the radial annular wall (31) of the sheath (30) are formed by an axial thickness variation of this wall (31).

11. System (19) according to any one of the preceding claims, wherein the male elements (50), or respectively female elements (60), of the collar (25) are engaged with clearances (J) in the female elements (60), or respectively male elements (50), of the radial annular wall (31) of the sleeve (30), these clearances (J) being located in a plane perpendicular to the axis (C).

12. System (19) according to any one of the preceding claims, wherein the male elements (50), or respectively female (60), of the collar (60) and the female elements (60), or respectively male (50), of the radial annular wall (31) of the sheath (30) have the same axial thickness.

13. System (19) according to any one of the preceding claims, wherein the collar (25) is inscribed in a circle which has a first diameter (d) less than a second internal diameter (D) of the cylindrical annular wall (32) of the sheath (30).

14. System (19) according to the preceding claim, wherein the difference between the first (d) and second (D) diameters is

15. greater than or equal to a radial thickness (E) of the cylindrical annular wall (32) of the sheath (30). Aircraft turbomachine, comprising a combustion chamber (1) equipped with at least one injection system (19) according to any one of the preceding claims.

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