Injection system for an annular combustion chamber of an aircraft turbine engine

Abstract

The invention relates to an injection system (19) for an annular combustion chamber of an aircraft turbine engine, this system comprising: - an annular member (19a), an annular collar (25); - an annular sheath (30) extending around the axis (C) and comprising a radial annular wall (31), an outer periphery of which is connected to a cylindrical annular wall (32) which surrounds the collar (25); and - a ring (40) added and secured to the sheath (30). According to the invention, the collar (25) comprises male (50) or female (60) elements fitted into female (60) or male (50) elements, respectively, having a complementary shape in the radial annular wall (31) of the sheath (30), wherein these male (50) and female (60) elements are surrounded by the cylindrical annular wall (32) of the sheath (30), which extends continuously over 360°.

Description

[0001] DESCRIPTION

[0002] TITLE: INJECTION SYSTEM FOR AN ANNULAR COMBUSTION CHAMBER OF AN AIRCRAFT TURBOMACHINE

[0003] Technical field of the invention

[0004] The present invention relates to an injection system for an annular combustion chamber of an aircraft turbomachine.

[0005] Technical background

[0006] Applications FR-A1-2 918 716, FR-A1-2 925 146, FR-A1-2 941 288, and FR-A1-2 975 467 describe turbomachinery injection systems. The technical background also includes documents EP-A2-1 731 837, US-A1-2012 / 204567, FR-A1-3 042 588, and FR-A1-3 108 162.

[0007] 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.

[0008] By convention, in this application, the terms "upstream" and "downstream" are defined with respect to the direction of gas flow within 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. Traditionally, the combustion chamber is annular and located within an annular enclosure radially delimited by an external annular casing and an internal annular casing. The combustion chamber is delimited by coaxial internal and external annular walls joined upstream by a chamber bottom, also annular, and substantially transverse.

[0009] The combustion chamber is supplied with compressed air, for example from a high-pressure compressor located upstream of the combustion chamber via an annular diffuser, and with fuel via injection systems arranged angularly around the chamber's axis of revolution. A conventional injection system includes an annular support and centering element for an injector head. This element incorporates augers that deliver airflow downstream of the injector to create an air-fuel mixture for injection and combustion in the combustion chamber. A truncated conical mixing bowl can be mounted downstream of the augers to atomize the air / fuel mixture entering the combustion chamber. The injector head support and centering element has a central bore designed to receive the injector head.The component may include a frustoconical surface that flares upstream and is connected at its downstream end, which is therefore the one with the smaller diameter, to 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.

[0010] The annular element slides between a sleeve and a bushing 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 around its own axis, hence the need to prevent its rotation.

[0011] In current technology, the rotation of the injector is prevented by a tab on the injector that bears against a stop on the sleeve. However, repeated contact between these components causes wear on both the tab and the sleeve, eventually necessitating the replacement of the injection system and the sleeve. Furthermore, since the sleeve is brazed to the chamber bottom, replacing it requires a complex and expensive operation.

[0012] The objective of the present invention is to provide a simple, effective and economical solution to at least one of the aforementioned problems.

[0013] Summary of the invention

[0014] The invention relates to an injection system for an annular combustion chamber of an aircraft turbomachine, this system comprising:

[0015] - an annular organ comprising:

[0016] • a central shaft opening suitable for receiving a fuel injector head,

[0017] • at least one annular tendril extending around said axis, and • an annular collar extending radially outwards from said axis,

[0018] - an annular sheath extending around said axis and comprising a radial annular wall, the outer periphery of which is connected to a cylindrical annular wall surrounding said collar, and

[0019] - 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.

[0020] 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°.

[0021] The invention thus provides for the elimination of the tab of the prior art and its replacement by a system of form(s) (male or female elements respectively, on the flange of the injection system) and counter-form(s) (female or male elements respectively, on the sleeve). This solution notably allows for a shift from linear contact (between the tab and the sleeve) to surface contact (between the form and its counter-form), thereby multiplying the contact points in the injection system. Increasing the contact points in this configuration, in particular, reduces wear on the injection system and considerably extends its lifespan. 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.

[0022] The invention makes it possible to achieve these objectives without thickening certain areas of the injection system or altering its positioning, thereby avoiding any impact on the performance of the annular combustion chamber, particularly during reignition. Furthermore, the internal and external diameters of the sleeve remain unchanged, thus avoiding any impact on the cooling of the chamber bottom and preventing any reduction in the movement of the component within its sleeve. The system according to the invention may include one or more of the following features, taken individually or in combination:

[0023] - the male elements, or respectively female elements, are at least two in number, preferably at least three in number, and for example at least four in number;

[0024] - the male elements, or respectively female elements, are regularly distributed around said axis;

[0025] - the male elements, or respectively female elements, are located on, or formed by, a peripheral contour of the collar;

[0026] - the peripheral outline of the collar has a general shape chosen from a plus sign and a square or triangular geometric shape;

[0027] - the peripheral contour of the collar includes straight and curved edges and is devoid of any protruding angle;

[0028] - the male elements, or respectively female elements, each have an angular range around the axis between 30 and 70°;

[0029] - 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;

[0030] - the male elements, or respectively female elements, each have an angular range around the axis between 10 and 30°;

[0031] - the female, or respectively male, elements of the radial annular wall of the sheath are formed by a variation in axial thickness of this wall;

[0032] - 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, these plays being located in a plane perpendicular to the axis;

[0033] - the male, or respectively female, elements of the collar and the female, or respectively male, elements of the radial annular wall have the same axial thickness;

[0034] - the collar is inscribed in a circle which has a first diameter less than a second internal diameter of the cylindrical annular wall of the sheath; - the difference between the first and second diameters is greater than or equal to a radial thickness of the cylindrical annular wall of the sheath;

[0035] The invention also relates to an aircraft turbomachine, comprising a combustion chamber equipped with at least one injection system as described above.

[0036] Brief description of the figures

[0037] 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 attached drawings in which:

[0038] [Fig.1] Figure 1 is a detailed 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;

[0039] [Fig.2] Figure 2 is an axial cross-sectional view of the injection system of Figure 1;

[0040] [Fig.3] Figure 3 is an exploded perspective view of the injection system according to a first embodiment seen from downstream to upstream;

[0041] [Fig.4] Figure 4 is an exploded perspective view of the injection system of Figure 3 seen from upstream to downstream;

[0042] [Fig.5] Figure 5 is an exploded perspective view of the injection system according to a second embodiment;

[0043] [Fig. 6] Figure 6 is a perspective view of the injection system 2 according to a third embodiment; and

[0044] [Fig.7] Figure 7 is a perspective view of the injection system according to a fourth embodiment.

[0045] Detailed description of the invention

[0046] Figure 1 shows an annular combustion chamber 1 of a gas generator of an aircraft turbomachine.

[0047] The combustion chamber 1 is located downstream of one or more compressors, for example, low-pressure and high-pressure compressors, and upstream of one or more turbines, for example, high-pressure and low-pressure turbines. The combustion chamber 1 is part of a turbomachine with a longitudinal X-axis, which is notably the axis of rotation of the compressor and turbine rotors.

[0048] According to the embodiment illustrated in Figure 1, the combustion chamber 1 is notably placed downstream of a high-pressure compressor and is, for example, placed here coaxially with the latter.

[0049] More specifically, chamber 1 is placed in an annular enclosure 5 radially delimited by an external annular casing 6 and an internal annular casing 7. The compressed air flow 8 generated by the compressor enters the enclosure 5 via an annular diffuser 9.

[0050] The combustion chamber 1 is delimited by internal and external coaxial annular walls 11, 12 joined upstream by a chamber bottom 13 which is also annular and substantially transverse.

[0051] More specifically, according to the embodiment illustrated in Figure 1, the chamber

[0052] I is substantially radially centered in enclosure 5 so as to define on the one hand an internal, annular air passage 14, radially delimited by the wall

[0053] II internal and the internal casing 7, and on the other hand an external, annular air passage 15, radially delimited by the external wall 12 and the external casing 6.

[0054] Chamber 1 is supplied with an air and fuel mixture by several air and fuel injection devices 16 distributed angularly and regularly around the X axis. More specifically, each injection device 16 includes a fuel injector 17 and an air injection system 19.

[0055] 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.

[0056] 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 chamber 1.

[0057] The injection system 19 includes means 19a for supporting and centering the injector head 18 (for example, an annular element 19a). The annular element 19a includes a central orifice with axis C adapted to receive the injector head 18, at least one annular spiral 19b extending around axis C and configured to form the airflow for mixing with the fuel injected by the injector head 18, and an annular flange 25 (visible in Figures 2 to 7) extending radially outward from axis C. The element 19a may also include means 19c for diffusing an air-fuel mixture into the chamber. The injection system 19 further includes an annular sleeve 30 and a ring 40 (visible in particular in Figures 2 to 5). In the embodiment examples shown in the figures, axis C forms an axis of revolution for the injection system 19.

[0058] 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 notably 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.

[0059] The 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.

[0060] 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".

[0061] 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.

[0062] 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.

[0063] The annular element 19a here comprises two annular spirals 19b. Each of the annular spirals 19b may include, in particular, 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.

[0064] 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°.

[0065] The ring 40 is attached to and fixed onto the sleeve 30, for example by welding, thus forming 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.

[0066] 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.

[0067] 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, preferably at least three, and for example at least four. The male elements 50 are, for example, regularly distributed around axis C. The female elements 60 are, in particular, regularly distributed around said axis C.

[0068] The male elements 50 (or respectively female elements 60) are located on, or formed by, a peripheral contour 28 of the collar 25.

[0069] In particular, in the example of the embodiment shown in Figures 3 and 4, the male elements 50 are located on the collar 25.

[0070] The male elements 50 (or respectively female elements 60) of the collar 25 are located in particular on a radial annular face 26 of the collar 25 and face the radial annular wall 31 of the sheath 30. The male elements 50, or respectively female elements 60, have here for example each an angular extent around the axis C of between 10 and 30°.

[0071] In this embodiment, the male elements 50 are in the form of a boss 51, specifically parallelepiped-shaped, formed from the material of 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 into the annular radial wall 31 of the sheath 30. The notches 61 are complementary in shape to the bosses 51 and are, for example, four in number. The notches 61 are distributed regularly along the sheath 30, for example, approximately every 90°.

[0072] 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 allows, in particular, for surface contact to be established 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 makes it possible to greatly limit the wear of the different parts of the injection system 19 according to the invention.

[0073] 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 (figure 5) and a square (figure 6) or triangular (figure 7) geometric shape.

[0074] In these embodiments, the peripheral contour 28 of the collar 25 includes straight and curved edges and has no salient angles. Indeed, in the embodiment shown in Figure 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 Figure 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.

[0075] In the embodiments shown in Figures 5 to 7, the male elements 50, or respectively female elements 60, each have an angular extent around axis C ranging from 30° to 70°. The female elements 60 (or respectively male elements 50) of the radial annular wall 31 of the sheath 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. The thin portion 31a defines the female elements 60 and is configured to receive the male elements 50 of the collar 25. The thin portion(s) 31a are connected to the thick portion(s) 31b by an axially extending internal rim 33 of the sheath 30.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 slice 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 31 a of the annular radial wall 31 of the sleeve 30 which makes it possible to greatly limit the wear of the different parts of the injection system 19.

[0076] In the embodiment shown in Figure 5, the sleeve 30 comprises four thin sections 31a configured to receive the four male elements 50 of the plus (+) shaped collar 25, such that each of the four arms of the + shape is received by the four thin sections 31a. The sleeve 30 further comprises four thick sections 31b interposed between the four thin sections 31a. In the embodiment shown in Figure 6, the sleeve 30 comprises a thin section 31a forming the female elements 60, in a geometric square shape, such that the thin section 31a is configured to receive the male elements 50 of the geometrically square collar 25. The sleeve 30 here comprises a thick section 31b at the periphery of the thin section 31a, connecting the thin section 31a to the cylindrical annular wall 32.In the embodiment shown in Figure 7, the sleeve 30 comprises a thin portion 31a forming the female elements 60, in a triangular geometric shape, such that the thin portion 31a is configured to receive the male elements 50 of the collar 25, also in a triangular geometric shape. The sleeve 30 here includes a thick portion 31b at the periphery of the thin portion 31a, which connects the thin portion 31a to the cylindrical annular wall 32.

[0077] 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.

[0078] 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.

[0079] 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 organ 19a within the sleeve 30. This movement facilitates, in particular, the guidance of the annular organ 19a within the sleeve 30 without compromising the rotational locking of the organ 19a around the axis C relative to the sleeve 30.

[0080] The collar 25 is inscribed in a circle which has a first diameter d (visible in figure 5) in particular less than a second internal diameter D of the cylindrical annular wall 32 of the sheath 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 sheath 30.

[0081] 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, this system comprising: - an annular organ (19a) comprising: • a central orifice with axis (C) suitable for receiving a fuel injector head (18), • at least one annular tendril (19b) extending around said axis (C), and • an annular collar (25) which extends radially outwards with respect to said axis (C), - an annular sheath (30) extending around said axis (C) and comprising a radial annular wall (31) whose outer periphery is connected to a cylindrical annular wall (32) which surrounds said collar (25), and - a ring (40) attached to and fixed onto the sheath (30), this ring (40) extending around said axis (C) and comprising 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), the collar (25) comprising 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°, in which the male (50), or respectively female (60), elements are located on, or formed by, a peripheral contour (28) of the collar (25),characterized in that the peripheral contour (28) of the collar (25) has a general shape chosen from a plus sign and a square or triangular geometric shape.

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 peripheral contour (28) of the collar (25) comprises straight and curved edges and is devoid of any salient angle.

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

6. 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).

7. 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).

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

9. 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).

10. System (19) according to the preceding claim, wherein 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 sheath (30).

11. 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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