Fuel injection system for turbomachine
The dual annular ring configuration with elastic support in the fuel injection system addresses wear-induced air leaks in turbomachines, enhancing system durability and performance.
Patent Information
- Application Number
- FR2023000163
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-01-06
- Publication Date
- 2026-02-27
- Estimated Expiration
- 2043-01-06
AI Technical Summary
Existing fuel injection systems in turbomachines suffer from material wear leading to air leaks and performance degradation due to thermal and vibrational stresses, necessitating frequent inspections and replacements.
A fuel injection system with a dual annular ring configuration, where a second annular ring is spherically connected to the first ring, decoupling translational and rotational degrees of freedom, and supported by elastic means to maintain the injection nozzle's position, reducing wear-induced air leaks.
The system effectively limits air leaks and maintains combustion chamber performance by resisting wear through a mechanically robust connection that decouples translational and rotational freedom, reducing the need for frequent maintenance.
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Abstract
Description
Title of the invention: Fuel injection system for turbomachinery technical field
[0001] This disclosure relates to the field of combustion chambers for a turbomachine, such as, for example, an aircraft turbojet or turboprop. More specifically, this disclosure concerns a fuel injection system for a combustion chamber. Previous technique
[0002] Fig. 1 schematically represents a twin-flow turbomachine 1 for aircraft. The turbomachine 1 generally comprises, from upstream AM to downstream AV according to the direction of gas flow within the turbomachine 1, a fan 2, a low-pressure compressor 3, a high-pressure compressor 4, a combustion chamber 5, a high-pressure turbine 6, a low-pressure turbine 7 and an exhaust system at the rear body of the turbomachine 1.
[0003] The gas flow, in particular air, entering upstream of the turbomachine 1 first circulates through the blower 2 and then divides, on the one hand, into an annular circulation channel called the primary channel 8, and on the other hand, into an annular circulation channel called the secondary channel 9 surrounding the primary channel 8. The low pressure compressor 3, the high pressure compressor 4, the combustion chamber 5, the high pressure turbine 6 and the low pressure turbine 7 are provided in the primary channel 8.
[0004] Fig. 2 represents the combustion chamber 5 of the turbomachine of Fig. 1. The combustion chamber 5 is annular in shape, with its axis coinciding with the X-axis of the turbomachine 1, and extends from upstream to downstream along the direction of the primary gas flow in the turbomachine 1. The combustion chamber conventionally comprises an annular space, in which combustion occurs, delimited by a coaxial radially internal annular wall 11 and a radially external annular wall 12. The radially internal annular walls 11 and 12 are connected at their upstream ends by a chamber bottom annular wall 16 extending substantially radially around the X-axis. Furthermore, fairings 15 are mounted at the upstream ends of the radially internal annular walls 11 and 12.
[0005] The bottom of the chamber 16 is equipped with air and fuel injection systems 17 regularly distributed around the X-axis and partially housed within the volume delimited by the fairings 15. Each injection system 17 is configured to inject a premix of air and fuel along a respective Y-axis into an opening arranged in the bottom of chamber 16. In operation, part of an airflow from the compressor supplies the injection systems 17 while another part of this airflow bypasses the combustion chamber by flowing downstream along the radially internal annular walls 11 and external annular walls 12 and passing through air inlet ports 13, 14 arranged in the radially internal annular walls 11 and external annular walls 12.
[0006] In the following description, the terms "axial," "radial," and "circumferential" are defined with respect to the so-called injection Y-axis. The terms "inner" and "outer," as well as "internal" and "external," are then defined according to the radial direction with respect to the injection Y-axis. The terms "upstream" and "downstream" are defined with respect to the direction of fuel injection in the injection system.
[0007] Generally, each injection system 17 comprises a fuel injection lance 18 and a sleeve 19 (also referred to as a "sliding sleeve"). The sleeve 19 is mounted, on one side, around the end of the lance (also called the injection nozzle 20) and, on the other side, to a downstream portion of the injection system, which is fixed to an edge of the corresponding opening in the bottom of the chamber 16. Positioning the sleeve 19 between the injection nozzle 20 and the downstream portion of the injection system facilitates and shortens the time required for mounting and dismounting the injector. Furthermore, the sleeve 19 provides degrees of freedom between the injection nozzle and the downstream portion of the injection system, thus compensating for play caused by thermal and vibrational stresses and the tolerances of the various components to which the injection system is subjected.
[0008] Furthermore, the downstream portion conventionally comprises an annular air inlet or injection device 21, a mixing bowl or vaporization bowl 22 essentially in the form of an annular wall having a frustoconical portion flared downstream, and a deflector 23. The air injection device 21 generally comprises several air inlet swirlers (also called "swirlers"), here two air injection swirlers, separated from each other by an annular wall that extends radially inwards to form an internal annular deflection wall, also called a venturi, having an internal profile that is convergent and then divergent from upstream to downstream. The air injection device 21 is mounted in the deflector 23, which is itself partially mounted in the opening of the bottom of the chamber 16.
[0009] In particular, on the one hand, the sleeve 19 comprises an annular radial wall arranged for free radial translation within an internal annular groove in the downstream part of the injection system. This configuration provides translational degrees of freedom in a plane perpendicular to the injection Y-axis between the sleeve 19 and the downstream part of the injection system. On the other hand, the sleeve 19 has a substantially cylindrical portion designed to fit around a substantially spherical portion of the injection nozzle 20. The injection nozzle 20 and the sleeve 19 are thus connected by a type The ball joint slides with each other with a precise adjustment. The injection nozzle 20 and the bushing 19 thus have, relative to each other, one degree of freedom in translation along the Y-axis of injection and degrees of freedom in rotation along axes perpendicular to the Y-axis of injection.
[0010] Such a configuration implies that the contact between the nozzle 19 and the injection nozzle 20 is substantially linear. However, due to this linear contact, material wear can occur during operation on the contacting surfaces of the injection nozzle and the nozzle. This wear can lead to unwanted air leaks between the injection nozzle 20 and the nozzle 19. This can alter the airflow distribution in the injection system and negatively impact combustion chamber performance. It is therefore necessary to carry out regular inspections of the injection nozzle and the nozzle to monitor their wear and replace them if excessive.
[0011] This document aims to provide a simple, reliable and economical solution to this need. Summary
[0012] A fuel injection system for a turbomachine combustion chamber is proposed. The injection system comprises an injection nozzle having an injection axis and a first annular ring coaxial with the injection nozzle, arranged radially outside the injection nozzle. The first ring is designed to be mounted freely in radial translation relative to a chamber bottom of the combustion chamber. The injection system further comprises a second annular ring coaxial with the injection nozzle, interposed between the injection nozzle and the first ring such that, on the one hand, the second ring and the injection nozzle are mechanically connected, allowing translation along the injection axis, and on the other hand, a second annular face of the second ring bears against a first annular face of the first ring. In other words, the second ring is spherically connected to the first ring.
[0013] Such an injection system offers the considerable advantage of maintaining the injection nozzle in position relative to the downstream part of the injection system, while limiting potential air leaks during operation between the respective elements of the injection system, for example, due to wear. Indeed, the installation of the second ring allows for the decoupling of the translational degree of freedom along the injection axis and the rotational degrees of freedom between the injection nozzle and the first ring. Specifically, the translational degree of freedom is achieved between the second ring and the injection nozzle, and the rotational degrees of freedom are achieved through the spherical joint between the first and second rings. This decoupling consequently allows for the implementation of mechanical connections that are more resistant to wear, and therefore limits potential air leaks within the injection system.
[0014] As previously stated, the terms "axial," "radial," and "circumferential" are defined with respect to the injection axis. The terms "inner" and "outer," as well as "internal" and "external," are then defined according to the radial direction with respect to the injection axis. The terms "upstream" and "downstream" are defined with respect to the direction of fuel injection in the injection system.
[0015] The features described in the following paragraphs may optionally be implemented independently of each other or in combination with each other.
[0016] The first face of the first ring and the second face of the second ring may advantageously each have a profile extending axially along the injection axis and radially to the injection axis.
[0017] Advantageously, the first face of the first ring and the second face of the second ring have complementary curved profiles.
[0018] The first ring may include a first collar having the first face on its radially internal periphery, the second ring including a second collar on its radially external periphery.
[0019] The injection system may include elastic means configured to exert a support force from the second face of the second ring on the first face of the first ring.
[0020] Advantageously, the elastic means can extend, at least partially, along the injection axis between the second ring and the injection nozzle so as to elastically connect the second ring and the injection nozzle. This ensures that surface contact is maintained between the first and second rings, and thus limits potential air leaks between the first and second rings.
[0021] According to one embodiment, the elastic means may advantageously include a cylindrical spring mounted in a tubular cavity of the second ring, an axial end of the cylindrical spring coming against a stop portion of the injection nose and an opposite axial end of the cylindrical spring coming against a bottom wall of the tubular cavity.
[0022] Advantageously, the tubular cavity of the second ring can be delimited by an internal cylindrical wall of the second ring in which the injection nose is engaged and centered in axial sliding and by an external cylindrical wall of the second ring.
[0023] The outer cylindrical wall of the second ring may include an annular rim extending radially inwards and positioned so that the stop portion of the injection nose is interposed axially between said annular rim and the cylindrical spring.
[0024] According to another embodiment, the elastic means may include a leaf spring device.
[0025] According to another aspect, a combustion chamber comprising an injection system as previously described is proposed.
[0026] According to another aspect, a turbomachine is proposed comprising an injection system as previously described or a combustion chamber as previously described. Brief description of the drawings
[0027] Other features, details and advantages will become apparent from reading the detailed description below and from analyzing the accompanying drawings, in which: Fig. 1
[0028] [Fig.1] schematically illustrates an example of a turbomachine. Fig. 2
[0029] [Fig.2] schematically illustrates an example of a combustion chamber. Fig. 3
[0030] [Fig.3] schematically illustrates a cross-sectional view of an example system injection according to this document. Fig. 4
[0031] [Fig.4] schematically illustrates another view of the example injection system according to this document. Fig. 5
[0032] [Fig.5] schematically illustrates another view of the example injection system according to this document. Fig. 6
[0033] [Fig.6] schematically illustrates a cross-sectional view of another example of a system injection according to this document. Description of the implementation methods
[0034] Reference is now made to [Fig. 3], which schematically represents a view of an example of a fuel injection system 100 according to this document for a combustion chamber. The injection system 100 can be configured to inject a mixture of air and fuel into the combustion chamber, for example as previously described with reference to [Fig. 2], which can be implemented in a turbomachine, for example as previously described with reference to [Fig. 1].
[0035] The combustion chamber 5 includes, in particular, a radially internal annular wall 11 and a radially external annular wall 12 coaxial with their axis corresponding to the X-axis of the turbomachine. The radially internal annular walls 11 and external 12 are connected at their upstream end by a radial annular wall of the bottom of chamber 16. The bottom of chamber 16 has regularly distributed openings around the circumference intended to be fitted with injection systems 100.
[0036] The injection system 100 includes a fuel injection rod 18 having at one end an injection nozzle 110 having an injection Y axis.
[0037] As previously stated, the terms "axial," "radial," and "circumferential" are defined with respect to the Y-axis of injection. The terms "inner" and "outer," as well as "internal" and "external," are then defined in terms of the radial direction with respect to the injection axis. The terms "upstream" and "downstream" are defined with respect to the direction of fuel injection in the injection system.
[0038] The injection system 100 includes a first annular ring 120 coaxial with the injection nose 110 arranged radially outside the injection nose 110 and a second annular ring 140 coaxial with the injection nose 110 interposed between the injection nose 110 and the first ring 120.
[0039] The first ring 120 is intended to be mounted freely in radial translation relative to the bottom of chamber 16 of the combustion chamber 5.
[0040] The first ring is in particular mounted downstream of a downstream part 130 of the injection system 100, which is fixed to an edge of a corresponding opening of the bottom of chamber 16.
[0041] The downstream portion 130 of the injection system 100 may, in particular, comprise, from upstream to downstream, an annular air injection device 21, a mixing bowl 22 essentially in the form of an annular wall having a frustoconical portion flared downstream, and a deflector 23. The air injection device 21 may include several air inlet swirlers (also called "swirlers"), here two air injection swirlers, separated from each other by an annular wall that extends radially inwards to form an internal annular deflection wall, also called a venturi, having an internal profile that is convergent and then divergent from upstream to downstream. The air injection device 21 is mounted in the deflector 23, which is itself partially mounted in the opening of the annular wall at the bottom of the chamber 16.
[0042] Figures 4 and 5 represent two views of the example injection system 100 according to this document.
[0043] The first ring 120 may, in particular, comprise an annular radial wall 121 and a first annular collar 123 extending radially and upstream from a radially internal end of the radial wall 121 of the first ring. The first collar 123 may, for example, extend substantially in an upstream direction and form an angle with the radial wall 121 of the first ring 120 of between 30° and 60°, preferably substantially equal to 45°.
[0044] The radial wall 121 can be configured to cooperate by sliding, according to a plane perpendicular to the Y-axis of injection, with an upstream radial surface 132 of the downstream part 130 of the injection system 100. Thus, the radial wall 121 of the first ring is advantageously in planar support against the upstream radial surface 132 of the downstream part 130 of the injection system 100.
[0045] More specifically, the downstream portion 130 may include an internal annular groove 131 opening radially inwards. The internal annular groove 131 may, for example, be part of the air injection device 21. The radial wall 121 of the first ring 120 may then bear against a radial surface furthest downstream of the internal annular groove 131. The radial wall 121 of the first ring 120 is, in particular, mounted freely in radial translation within said internal annular groove 131.
[0046] The first ring 120 can alternatively be fixed to the downstream part 130 of the injection system 100. The sliding cooperation between the first ring and the bottom of the chamber 16 can then be carried by an element of the downstream part of the injection system 100.
[0047] The second ring 140 is interposed between the injection nozzle 110 and the first ring 120. The second ring 140 and the injection nozzle 110 are mechanically linked allowing translation along the Y-axis of injection.
[0048] The second ring 140 includes in particular a cylindrical part 141 mounted around the injection nozzle 110, which can translate along the Y-axis of injection relative to the injection nozzle 110.
[0049] Furthermore, the second ring 140 may in particular include a second annular collar 143 extending radially and upstream from a radially external end of the cylindrical part 141 of the second ring 140. The second annular collar is configured to bear against the first collar 123 of the first ring 120. Thus, the second collar 143 may, for example, extend substantially in the same direction as the first collar 123.
[0050] Furthermore, a second annular face 142 of the second ring 140, notably supported by the second flange 143 on its radially external periphery, bears against a first annular face 122 of the first ring 120, notably supported by the first flange 123 on its radially internal periphery. In other words, the second ring 140 is spherically connected to the first ring 120. The flanges, by virtue of their shape, provide flexibility to the connection between the first ring and the second ring. The spherical connection allows rotation of the injection nozzle relative to the first ring along axes perpendicular to the injection Y-axis.
[0051] Such an injection system offers the considerable advantage of maintaining the injection nozzle in position relative to the downstream part of the injection system, while limiting any potential air leaks during operation between the respective elements of the system injection, for example, due to wear. Indeed, the addition of the second ring allows for the decoupling of the translational degrees of freedom along the injection axis from the rotational degrees of freedom between the injection nozzle and the first ring. Specifically, the translational degrees of freedom are achieved between the second ring and the injection nozzle, while the rotational degrees of freedom are achieved through the spherical joint between the first and second rings. This decoupling consequently allows for the implementation of mechanical connections that are more resistant to wear, thus limiting potential air leaks within the injection system.
[0052] More specifically, the first face 122 of the first ring 120 and the second face 142 of the second ring 140 can each have a profile extending axially along the injection Y-axis and radially to the injection Y-axis. In other words, the profile of said first face 122 and said second face 142 can extend in a direction comprising a radial component and an axial component. This makes it possible to create a surface support that more readily allows rotations about axes perpendicular to the injection Y-axis.
[0053] The first face 122 of the first ring 120 and the second face 142 of the second ring 140 may have complementary curved profiles. The profiles may be curved radially inwards and upstream. This shape allows the injection nozzle to be brought back towards its axis in the event of thermomechanical stresses during operation.
[0054] In addition, the injection system 100 may include elastic means 150 configured to exert a support force from the second face 142 of the second ring 140 on the first face 122 of the first ring 120. This ensures that surface contact is maintained between the first ring and the second ring, and thus limits potential air leaks between the first ring and the second ring.
[0055] More specifically, the elastic means 150 can extend, at least in part, along the Y-axis of injection between the second ring 140 and the injection nozzle 110 so as to elastically connect the second ring 140 and the injection nozzle 110. Thus, the injection nozzle 110, by virtue of its positioning, can exert a force against the elastic means 150, which in turn exert a force against the second ring so that the latter presses against the first ring.
[0056] With reference to figures 4 and 5, the elastic means 150 may include a cylindrical spring 151 mounted in a tubular cavity 144 of the second ring 140. An axial end of the cylindrical spring 151 abuts against a stop portion 111 of the injection nozzle 110 and an opposite axial end of the cylindrical spring 151 abuts against a bottom wall of the tubular cavity 144.
[0057] The stop portion 111 of the injection nozzle extends radially beyond the injection nozzle, particularly at an upstream end of the injection nozzle. Thus, the The cylindrical spring 151 can extend substantially along the length of the injection nozzle.
[0058] The tubular cavity 144 of the second ring 140 can in particular be delimited on the one hand by an internal cylindrical wall 145 of the second ring 140 in which the injection nozzle 110 is engaged and axially centered and by an external cylindrical wall 146 of the second ring 140.
[0059] The outer cylindrical wall 146 of the second ring 140 may include an annular rim 147 extending radially inwards and positioned so that the stop portion 111 of the injection nose is interposed axially between said annular rim 147 and the cylindrical spring 151.
[0060] Figure 6 shows a partial cross-sectional view of another example of an injection system 100 according to this document. The elastic means 150 include, in particular, a leaf spring device 152.
[0061] The leaf spring device 152 can in particular be interposed between the injection nozzle 110 and the second ring 140 and arranged radially outside the cylindrical part 141 of the second ring 140. More specifically, the leaf spring device 152 can bear at one axial end against a portion of the stop 111 of the injection nozzle, and at an opposite axial end against an upstream end of the second flange 143 of the second ring 140.
[0062] Furthermore, the radial wall 121 of the first ring 120 can be fixed to the downstream part 130 of the injection system 100, in particular to the air injection device. Sliding cooperation between the first ring and the bottom of the chamber 16 can then be achieved by another radial wall of the downstream part of the injection system 100, this other radial wall being able to come against a radial surface of the bottom of the chamber 16.
Claims
Demands
1. Fuel injection system (100) for a combustion chamber (5) for a turbomachine (1), the injection system (100) comprising: - an injection nozzle (110) having an injection axis (Y), - a first annular ring (120) coaxial with the injection nozzle (110) arranged radially outside the injection nozzle (110), the first ring (120) being intended to be mounted freely in radial translation relative to a chamber bottom (16) of the combustion chamber (5), wherein the injection system (100) comprises a second annular ring (140) coaxial with the injection nozzle (110) interposed between the injection nozzle (110) and the first ring (120) such that, on the one hand, the second ring (140) and the injection nozzle (110) are mechanically connected allowing translation along the axis (Y) injection and that, on the other hand,a second annular face (142) of the second ring (140) bears against a first annular face (122) of the first ring (120).
2. Injection system (100) according to claim 1, wherein the first face (122) of the first ring (120) and the second face (142) of the second ring (140) each have a profile extending axially along the injection axis (Y) and radially to the injection axis (Y).
3. Injection system (100) according to any one of claims 1 or 2, wherein the first face (122) of the first ring (120) and the second face (142) of the second ring (140) have curved profiles that are complementary to each other.
4. Injection system (100) according to any one of claims 1 to 3, wherein the first ring (120) comprises a first collar (123) having the first face (122) on its radially internal periphery, the second ring (140) comprising a second collar (143) on its radially external periphery.
5. Injection system (100) according to any one of claims 1 to 4, comprising elastic means (150) configured to exert a support force of the second face (142) of the second ring (140) on the first face (122) of the first ring (120).
6. Injection system (100) according to claim 5, wherein the elastic means (150) extend, at least in part, along the axis (Y) injection between the second ring (140) and the injection nozzle (110) so as to elastically connect the second ring (140) and the injection nozzle (110).
7. Injection system (100) according to any one of claims 5 or 6, wherein the elastic means (150) comprise a cylindrical spring (151) mounted in a tubular cavity (144) of the second ring (140), an axial end of the cylindrical spring (151) bearing against a stop portion (111) of the injection nozzle (110) and an opposite axial end of the cylindrical spring (151) bearing against a bottom wall of the tubular cavity (144).
8. Injection system (100) according to claim 7, in which the tubular cavity (144) of the second ring (140) is delimited by an internal cylindrical wall (145) of the second ring (140) in which the injection nozzle (110) is engaged and axially sliding centered and by an external cylindrical wall (146) of the second ring (140).
9. Injection system (100) according to the preceding claim, wherein the outer cylindrical wall (146) of the second ring (140) comprises an annular rim (147) extending radially inwards and positioned so that the stop portion (111) of the injection nozzle (110) is axially intercalated between said annular rim (147) and the cylindrical spring (151).
10. Injection system (100) according to any one of claims 5 to 7, wherein the elastic means (150) comprise a leaf spring device (152).
11. Combustion chamber (5) comprising an injection system (100) according to any one of the preceding claims.
12. Turbomachine (1) comprising an injection system (100) according to any one of claims 1 to 10 or a combustion chamber (5) according to claim 11.