Corrugated injector for combustion chamber injection device

Abstract

The invention relates to an injector (30) for a gaseous fuel injection device (10) with a longitudinal axis (X) intended to be mounted on the bottom (94) of a turbomachine combustion chamber (90). The injector (30) extends from upstream to downstream along a longitudinal axis (X). The injector (30) has an upstream edge (40) and a downstream edge (50) provided with fuel injection holes (60). The upstream edge (40) has a first corrugation (41) along a first transverse direction (Y) perpendicular to the longitudinal axis (X) and a second corrugation (42) along the longitudinal axis (X). The downstream edge (50) has a third corrugation (53) along the first transverse direction (Y) and a fourth corrugation (54) along the longitudinal axis (X). Figure 2

Description

Title of the invention: Corrugated injector for combustion chamber injection device

[0001] The invention relates to the field of combustion chambers of aircraft turbomachinery powered by a gaseous fuel such as dihydrogen and air. These aircraft include winged aircraft for civil or military aviation, helicopters, VTOLs, drones, APUs, turbojets, and turboprops.

[0002] In the case where the turbomachine is a twin-spool, twin-flow aircraft turbomachine extending along a longitudinal axis, the upstream compressor compresses the air that has entered the turbomachine from the upstream end. This air is admitted into the combustion chamber of the downstream turbomachine. The hot gases from this combustion are then expanded in a downstream turbine, causing this turbine to rotate. The rotation of this turbine drives the rotor of the turbomachine on which this turbine is mounted. The rotor, in turn, drives the rotation of the compressor and the fan blades located upstream of the turbomachine. The rotation of the fan blades, along with the high-speed ejection of the gases exiting the combustion chamber, contributes to the propulsion of the turbomachine.

[0003] The combustion chamber is annular and includes a plurality of injection devices which are distributed circumferentially on the bottom of the combustion chamber and which inject the fuel into the combustion chamber.

[0004] Thus, an injector is known for a gaseous fuel injection device intended to be mounted in a turbomachine combustion chamber, the injector extending from upstream to downstream along a longitudinal axis X, the injector having an upstream edge and a downstream edge provided with fuel injection holes.

[0005] During operation of the turbomachine, difficulties may sometimes be encountered in the gaseous fuel injection device, including flame instability downstream of the injectors in the operating range of the turbomachine, flame sticking at the downstream end of the injectors, and the phenomenon of "flashback" (flame returning upstream).

[0006] Furthermore, for environmental reasons, efforts are being made to use gaseous fuels other than kerosene (which is not gaseous), which emit fewer polluting carbon dioxide gases such as NOx, particulate matter, and fumes. One such less polluting fuel is dihydrogen. However, using dihydrogen as a fuel exacerbates the above-mentioned drawbacks, especially the risk of flashback and combustion instabilities, because the flame speed is approximately ten times faster for hydrogen than for kerosene. Description of the invention

[0007] The present invention aims to remedy these drawbacks.

[0008] The invention aims to provide an injector for a gaseous fuel injection device that provides more stable combustion over the entire combustion range, i.e. flame stability over the operating range of the turbomachine.

[0009] This goal is achieved thanks to the fact that the upstream edge has a first undulation along a first transverse direction Y perpendicular to the longitudinal axis X and a second undulation along the longitudinal axis X and in that the downstream edge has a third undulation along the first transverse direction Y and a fourth undulation along the longitudinal axis X.

[0010] Thanks to these arrangements, the undulations of the upstream and downstream edges of the injector along two perpendicular directions more effectively form vortices in the gas flow passing through the injection device, particularly downstream of the downstream edge. This improves the mixing between the gas and the fuel and helps prevent flame sticking to the injectors, stabilizes the flame, and avoids flame flashback phenomena, especially when the fuel is hydrogen.

[0011] For example, the undulations are periodic and are entirely curvilinear.

[0012] For example, the wavelengths of the third and fourth waves are smaller than the wavelengths of the first and second waves.

[0013] For example, the injection holes are arranged irregularly with respect to each other.

[0014] The invention also relates to a gaseous fuel injection device with a longitudinal axis (X) intended to be mounted in a turbomachine combustion chamber, the injection device comprising at least one injector according to the invention.

[0015] For example, the injection device comprises at least two flanges and at least one injector extending in a plane defined by the longitudinal axis X and a second transverse direction Z perpendicular to the first transverse direction Y and to the longitudinal axis X, each of the at least two flanges extending in a plane parallel to this plane and the at least one injector being located between two adjacent flanges.

[0016] For example, the injection device comprises at least two coaxial annular flanges with longitudinal axis X, such that at least one injector is located between two adjacent flanges, and is annular and coaxial with these flanges, the first transverse direction Y being radial and a second transverse direction Z perpendicular to the first transverse direction Y and to the longitudinal axis X being circumferential.

[0017] For example, the injection device includes at least one helical flange with longitudinal axis X, such that at least one injector is helical and extends over at least a part of its helical length between two radially adjacent portions of at least one flange and is coaxial with at least one flange, the first transverse direction Y being radial and a second transverse direction Z perpendicular to the first transverse direction Y and said longitudinal axis X being circumferential.

[0018] The invention also relates to a combustion chamber comprising a plurality of injection devices according to the invention, distributed along the bottom of this chamber.

[0019] The invention also relates to a turbomachine comprising a combustion chamber according to the invention.

[0020] The invention will be better understood and its advantages will become more apparent upon reading the following detailed description of embodiments shown by way of non-limiting examples. The description refers to the accompanying drawings in which:

[0021] [Fig.1] Fig.1 is a longitudinal cross-sectional view of a combustion chamber of a turbomachine carrying an injection device according to the invention.

[0022] [Fig.2] Fig.2 is a front view along the longitudinal axis X of a device injection according to a first embodiment of the invention.

[0023] [Fig.3] Fig.3 is a perspective view of an injector of the injection device of the [Fig.2].

[0024] [Fig.4] Fig.4 is a front view along the longitudinal axis X of the injector of the [Fig.3],

[0025] [Fig.5] Fig.5 is a top view along the first transverse direction Y of the injector of [Fig.3].

[0026] [Fig.6] Fig.6 is a front view along the longitudinal axis X of a device injection according to a second embodiment of the invention.

[0027] [Fig.7] Fig.7 is a front view along the longitudinal axis X of a device injection according to a third embodiment of the invention. Detailed description of the invention

[0028] In the description below, the terms "internal" and "inner" refer to an element oriented towards a reference axis or located closer to that axis. The terms "external" and "outer" refer to an element oriented in the opposite direction to that reference axis or located further from that axis. The terms "upstream" and "downstream" are relative to the direction of air and gas flow during the operation of the turbomachine, i.e., from left to right in [Fig. 1]. The term "radial" refers to a position or direction in a transverse plane perpendicular to the reference axis and passing through that reference axis.

[0029] Consider a turbomachine with longitudinal axis A, which is its axis of rotation. This turbomachine comprises a compressor, a combustion chamber 90, and a turbine. The combustion chamber 90 is located in a section of the turbomachine downstream of the compressor and upstream of the turbine. Air compressed by the compressor enters the combustion chamber 90, and fuel is injected into this combustion chamber 90 where it is burned with this compressed air. The hot gases generated by this combustion are ejected at high speed into the turbine.

[0030] As shown in [Fig. 1], the combustion chamber 90 is annular and is mounted between an inner shell 91 and an outer shell 92, which are cylindrical and coaxial with longitudinal axis A. These two shells (91, 92) define an annular space that is open upstream to a diffuser 93 which communicates with the compressor (not shown). The combustion chamber 90 is delimited by a bottom wall 94 located upstream, an inner shell 95 and an outer shell 96 coaxial with longitudinal axis A, and is open downstream to the turbine. The shells (95, 96) are assembled and fixed to the shells (93, 94) by flanges. The bottom wall 94 is substantially transverse with respect to the gas flow axis in the combustion chamber 90 and is provided with a plurality of circular openings 97. A fairing 98 located upstream of these openings 97 guides the air from the diffuser 93 towards these openings 97.For each opening 97, fuel is supplied via a pipe 99 to an injection device 10, which atomizes the fuel into the airflow to form a mixture. This mixture enters the combustion chamber 90 along a longitudinal axis X, which is the principal axis of the injection device 10 and the direction of gas flow through the injection device 10. The longitudinal axis X passes through the center of the injection device 10. The injection device 10 is delimited by a wall 11. For example, this wall is cylindrical with a circular cross-section, as shown in the figures. The principal axis X of the injection device 10 is parallel, or not parallel, to the longitudinal axis A.

[0031] A first transverse direction Y (first transverse axis Z) is defined as perpendicular to the longitudinal axis X, and a second transverse direction Z (second transverse axis Z) is defined as perpendicular to the first transverse direction Y and to the longitudinal axis X. A transverse plane is defined that is perpendicular to the longitudinal axis X, and which therefore extends along the first transverse direction Y and the second transverse direction Z. The longitudinal axis X is defined with respect to the injection device 10 and is therefore of constant orientation. The transverse directions (Y, Z) are defined at a given point of an injector 30 (see below). The transverse directions (Y, Z) are therefore either of constant orientation if the injector(s) 30 extend in parallel planes (first embodiment shown below). below), or of variable orientation if the injector(s) 30 are curved (second and third embodiments described below).

[0032] The injection device 10 optionally includes at least one flange 20 and at least one injector 30 extending from upstream to downstream along the longitudinal axis X (longitudinal direction X). The flange(s) 20 extend along the longitudinal axis X, or alternatively, extend along an axis distinct from the longitudinal axis X. The injector 30, or in certain embodiments each of the injectors 30, is surrounded by one or two adjacent flanges 20. Thus, two adjacent flanges 20 define a space in which an injector 30 is located, and the quantity of air passing around the injector 30 can be regulated by adjusting the distance between these two adjacent flanges 20. Depending on the geometry of the flanges 20, this space is for example rectangular in section (first embodiment below), annular in section (second embodiment below) or helical in section (third embodiment below).

[0033] The injector(s) 30 have an upstream edge 40 (leading edge with respect to the gas flow) and a downstream edge 50 (trailing edge with respect to the gas flow) provided with fuel injection holes 60, these two edges (40, 50) extending perpendicularly to the longitudinal axis X. The fuel enters the combustion chamber 90 through the injection holes 60. The downstream ends of the downstream edge 50 of an injector 30 may be located at the same level, upstream, or downstream along the longitudinal direction X with respect to the downstream edge of a flange 20 that is adjacent to this injector 30. The upstream edge 40 has a first corrugation 41 along the first transverse direction Y and a second corrugation 42 along the longitudinal axis X. The downstream edge 50 has a third corrugation 53 along the first transverse direction Y and a fourth corrugation 54 along the longitudinal axis. X.By "an edge which extends along a direction S exhibits an undulation along a direction T" we mean that the edge has the form of a periodic or non-periodic function F of equation t = F(s) in the coordinate system whose abscissa "s" is along the direction S and the ordinate "t" is along the direction T.

[0034] Figure 3 illustrates a perspective view of an injector 30, where all these undulations (41, 42, 53, 54) are visible. On the upstream edge 40, the first undulation 41 is shown as a dashed line, and the second undulation 42 undulates along the longitudinal axis X around the first undulation 41. Similarly, on the downstream edge 50, the third undulation 53 is shown as a dashed line, and the fourth undulation 54 undulates along the longitudinal axis X around the third undulation 53. The first undulation 41 and the third undulation 53 are visible in Figure 4, which is a front view (in the transverse plane (Y, Z)) of an injector 30. In this example, these undulations (41, 53) have the same period and are out of phase. The second undulation 42 and the fourth undulation 54 are visible in [Fig. 5], which is a top view (in the (X, Z) plane of an injector 30. In this example these undulations (42, 54) have different periods.

[0035] When they are periodic, the ripples (41, 42, 53, 54) can have any shape. For example, as illustrated in the figures, each of the ripples (41, 42, 53, 54) is sinusoidal, that is to say that each function t = F(s) defining a ripple (41, 42, 53, 54) is a sinusoid.

[0036] The undulations of the upstream edge 40 and the downstream edge 50 along two perpendicular directions (Y, X) more effectively form vortices in the gas flow which passes through the injection device 10, particularly downstream of the trailing edge 50 of the injectors 30.

[0037] Advantageously, the undulations are entirely curvilinear, meaning that the edges have no angles. In other words, each function t = F(s) that represents an undulation on an edge has no inflection point. This simplifies the manufacturing of the injectors 30. In particular, the injectors 30 can be manufactured by additive manufacturing or by injection molding.

[0038] A first embodiment of the invention is described below in which the injectors 30 each extend in a plane.

[0039] The injection device 10 comprises a plurality of flanges 20 that are substantially flat and parallel to each other, and at least one injector 30, each injector 30 being located between two adjacent flanges 20. The flanges 20 and the injectors 30 each extend in a plane along the longitudinal direction X and the second transverse direction Z. The first transverse direction Y is therefore perpendicular to the flanges 20 and the injectors 30. The first transverse direction Y and the second transverse direction Z are constant. This configuration is shown in [Fig. 2] in the case of four flanges 20 and three injectors 30. This injector 30 is shown in Figures 3 to 5.

[0040] For example, the injection device comprises two flanges 20 and an injector 30 sandwiched between these two flanges 20. Tests carried out by the inventors in this configuration show that an optimal arrangement is with a distance (along the first transverse direction Y) between two adjacent flanges equal to 100 mm and a flange width 20 and injector width 30 (along the second transverse direction Z) equal to 100 mm. In the longitudinal direction X, the downstream edge 50 of the injector 30 is downstream of the downstream edge of the flanges 20 by a maximum distance of 30 mm.

[0041] A second embodiment of the invention is described below in which the injectors 30 are annular.

[0042] The injection device 10 comprises a plurality of coaxial annular flanges 20 with longitudinal axis X and a plurality of coaxial annular injectors 30 with the flanges 20, each injector 30 being located between two adjacent flanges 20 except for the most central injector 30 and the injector 30 furthest from the longitudinal axis X. The injectors 30, and therefore their upstream edges 40 and downstream edges 50, are curved. The first corrugation 41 and the third corrugation 53 follow these curved edges. In this configuration, the first transverse direction Y is radial and the second transverse direction Z is circumferential. Thus, the direction of the first transverse direction Y and the direction of the second transverse direction Z vary as one moves along an injector 30 around the longitudinal axis X. This configuration is shown in [Fig. 6] in the case of three flanges 20 and two injectors 30. Alternatively, an additional flange 20 can be located at the center of the most central injector 30 and an additional flange 20 can surround the injector 30 furthest from the longitudinal axis X, such that each injector 30 is located between two adjacent flanges 20.

[0043] A third embodiment of the invention is described below in which the injectors 30 are helical.

[0044] The injection device 10 comprises at least one helical flange 20 with longitudinal axis X and at least one helical injector 30 that is coaxial with this flange 20 and extends over at least a portion of, for example, its entire helical length between two radially adjacent portions of the flange 20. The injectors 30, and therefore their upstream edges 40 and their downstream edges 50, are curved. The first corrugation 41 and the third corrugation 53 follow these curved edges. In this configuration, the first transverse direction Y is radial and the second transverse direction Z is circumferential. Thus, the direction of the first transverse direction Y and the direction of the second transverse direction Z vary as one moves along an injector 30 around the longitudinal axis X. This configuration is represented in [Fig.7] in the case of a flange 20 and an injector 30.

[0045] In all embodiments, each of the undulations (41, 42, 53, 54) has a different period and / or is out of phase with respect to the other. This makes the air-fuel mixture more efficient and helps to better prevent flame sticking to the injector 30. For example, the first undulation 41 and the third undulation 53, both of which are along the first transverse direction Y, are out of phase, as shown in [Fig. 4]. Alternatively, at least two of the undulations (41, 42, 53, 54) have the same period and / or are in phase.

[0046] Advantageously, the wavelengths of the third wave 53 and the fourth wave 54 are shorter than the wavelengths of the first wave 41 and the second wave 42. Thus, the mixing of air and fuel is optimized.

[0047] The fuel injection holes 60 are arranged along the downstream edge 50. For example, these injection holes 60 are evenly distributed along the downstream edge 50. Advantageously, these injection holes 60 are arranged irregularly with respect to each other, that is to say, the distances between two adjacent injection holes 60 are not equal. Thus, the air-fuel mixture downstream of the injection holes 60 is optimized.

[0048] The flanges 20 and injectors 30 are fixed to the wall 11. Alternatively or additionally, the injection device 10 further comprises a support 70 which is integral with the wall 11 and to which the flanges 20 and injectors 30 are fixed. For example, as shown in Figures 2, 6, and 7, the support 70 comprises one or more plates that pass through the longitudinal axis X and are oriented at different angles. For example, the support 70 is shaped to direct the gas flow through the injection device 10 in a direction different from that of the longitudinal axis X, and / or to generate vortices in this gas flow.

[0049] The invention also relates to a combustion chamber comprising a plurality of injection devices 10 as described above. These injection devices are distributed along the bottom 94 of this chamber 90. For example, this chamber is annular.

[0050] The invention also relates to a turbomachine comprising a combustion chamber 90 according to the invention.

Claims

Demands

1. Injector (30) for a gaseous fuel injection device (10) intended to be mounted in a turbomachine combustion chamber (90), said injector (30) extending from upstream to downstream along a longitudinal axis (X), said injector (30) having an upstream edge (40) and a downstream edge (50) provided with fuel injection holes (60), said injector (30) being characterized in that said upstream edge (40) has a first corrugation (41) along a first transverse direction (Y) perpendicular to said longitudinal axis (X) and a second corrugation (42) along said longitudinal axis (X) and in that said downstream edge (50) has a third corrugation (53) along said first transverse direction (Y) and a fourth corrugation (54) along said longitudinal axis (X).

2. Injector (30) according to claim 1 such that said undulations (41, 42, 53, 54) are periodic and are entirely curvilinear.

3. Injector (30) according to claim 1 or 2 such that the wavelengths of said third wave (53) and of said fourth wave (54) are less than the wavelengths of said first wave (41) and of said second wave (42).

4. Injector (30) according to any one of claims 1 to 3 such that said injection holes (60) are arranged irregularly with respect to each other.

5. Longitudinal (X) axis gaseous fuel injection device (10) for mounting in a turbomachine combustion chamber (90), said injection device (10) comprising at least one injector (30) according to any one of claims 1 to 4.

6. Injection device (10) according to claim 5, wherein it comprises at least two flanges (20) and at least one injector (30) extending in a plane defined by said longitudinal axis (X) and a second transverse direction (Z) perpendicular to said first transverse direction (Y) and said longitudinal axis (X), each of said at least two flanges (20) extending in a plane parallel to this plane and said at least one injector (30) being located between two of said adjacent flanges (20).

7. Injection device (10) according to claim 5, wherein it comprises at least two coaxial annular flanges (20) with longitudinal axis (X), wherein at least one injector (30) is located between two of said flanges flanges (20) adjacent and is annular and coaxial with said flanges (20), said first transverse direction (Y) being radial and a second transverse direction (Z) perpendicular to said first transverse direction (Y) and said longitudinal axis (X) being circumferential.

8. Injection device (10) according to claim 5, wherein it comprises at least one helical flange (20) with longitudinal axis (X), wherein said at least one injector (30) is helical and extends over at least a portion of its helical length between two radially adjacent portions of said at least one flange (20) and is coaxial with said at least flange (20), said first transverse direction (Y) being radial and a second transverse direction (Z) perpendicular to the first transverse direction (Y) and said longitudinal axis (X) being circumferential.

9. Combustion chamber (90) comprising a plurality of injection devices (10) according to any one of claims 5 to 8, distributed along said bottom (94) of this chamber (90).

10. Turbomachine comprising a combustion chamber (90) according to claim 9.

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