Injection assembly for aircraft turbomachine and combustion device including the injection assembly

Abstract

Injection assembly (70) for aircraft turbomachine comprising: a fuel mixture channel (30) for supplying a combustion chamber (90) with a fuel mixture flow (32), an external air channel (40) for supplying the combustion chamber (90) with an external air flow (42) extending around the fuel mixture flow (32), an internal air channel (50) extending coaxially with the fuel mixture channel (30) for supplying the combustion chamber (90) with an internal air flow (52) surrounded by the fuel mixture flow (32), a plurality of vanes (55) extending in the fuel mixture channel (30), the vanes (55) each containing a through channel (53) for supplying the internal air channel (50) with an internal air flow (52) passing through the through channels (53). Figure for the abbreviation: Figure 2

Description

Title of the invention: Injection assembly for aircraft turbomachine and combustion device comprising the injection assembly. Scope of disclosure

[0001] This disclosure relates to combustion devices for gas turbines such as aircraft turbomachinery powered by hydrogen and air. This includes, in particular, civil and military aeronautical applications: helicopters, vertical takeoff and landing aircraft (VTOL), drones, auxiliary power units (APUs), turbogenerators, fixed-wing aircraft for recreational, business, or commercial aviation, turbojets, or turboprops. This disclosure further relates to a combustion device comprising the injection assembly and a combustion chamber. State of the art

[0002] The propulsion sector, and in particular the aeronautical sector, faces major environmental challenges. The interest in using hydrogen combustion rather than kerosene is growing stronger, because hydrogen combustion avoids carbon-based pollutant emissions such as carbon dioxide, carbon monoxide, unburned hydrocarbons, and fine particles and smoke.

[0003] A principle for micro-mixing air-dihydrogen burners is known. Burners based on this principle are complex to integrate and can present problems associated with the interaction between different flames, which have an adverse effect on flame propagation and / or thermo-acoustic stability. Such burners present a risk of high manufacturing and mass costs and are specific to a given combustion chamber architecture.

[0004] A direct hydrogen injection system has also been described in document WO2023 / 180318 Al.

[0005] At the level of injection and combustion, two main technological configurations for hydrogen-air injection systems applied to gas turbines exist, namely lean injection systems, and rich injection systems.

[0006] More generally, it is important to note that lean-burn fuel supply processes tend to generate significant thermoacoustic instabilities that can damage these systems and create risks of flashback, whereas stable combustion is necessary to avoid altering the engine performance. Rich combustion fuel processes, on the other hand, tend to emit more pollutants than lean combustion processes if they are not properly sized.

[0007] The use of hydrogen involves several issues to be taken into consideration at the combustion chamber level:

[0008] Under equivalent thermodynamic conditions of pressure, temperature, and air-fuel ratio, the adiabatic temperature of the flame in a hydrogen-air combustion is higher than that of the flame in a kerosene-air combustion, particularly in the case of a rich mixture, which can lead to an uncontrolled increase in nitrogen oxides. However, the flammability limits of hydrogen are wider than those of kerosene, allowing the mixture to ignite at lower or higher air-fuel ratios than kerosene.

[0009] Similarly, the flame speeds resulting from hydrogen-air combustion are higher than for kerosene-air flames. A high flame speed can lead to flashback problems in injection systems, particularly at the boundary layers, and cause serious damage to these systems.

[0010] Finally, the combustion of hydrogen with air tends to emit much more noise than an air-kerosene combustion and can therefore generate significant noise pollution at airports, in the case of aeronautical use.

[0011] It is therefore sought to reduce combustion temperatures, to reduce sound waves from combustion and to limit the formation of nitrogen oxides in order to reduce both noise pollution and air pollution during the operation of the turbines.

[0012] At the burner level, documents GB2502298A and US6267585B1 describe chamber geometries based on the principle of a micromix burner. This type of burner is designed to miniaturize the reaction zone by creating a multitude of diffusion micro-flames up to 4 centimeters long. The combustion process relies on the injection of hydrogen perpendicular to an airflow that carries the hydrogen (known as jet-in-crossflow). Once the hydrogen has been rapidly added to the air, the mixture is injected into the combustion chamber and burned downstream of a multitude of injection holes. This technology reduces the risk of flashback, as there is no premixing before injection.The operability of this type of injector can be limited, as can the thermal resistance of the wall containing the injection holes, which is subjected to high temperatures. Furthermore, and most importantly, this technology presents problems, previously mentioned in the relevant section. with other technologies, integration, flame propagation, thermo-acoustic instabilities and potentially complex development for micro-mixing systems, which is particularly penalizing in an aeronautical application where operability is very important.

[0013] In the context of burners using kerosene, the document “Advanced Combustor Systems for Stationary Gas Turbine Engines, Phase I. Review and Preliminary Evaluation, Volume I”, SA Mosier, RM Pierce, Contract 68-02-2136, FR-11405, Final Report, US Environmental Protection Agency, 1980 proposes a geometry of type RQL according to the acronym used in the field for “Rich Burn-Quick Mix-Lean Burn” in English, or rich combustion-quick mix-lean combustion in French.

[0014] This geometry aims to stagger the air-kerosene mixture in the combustion chamber across several zones: a first zone near the injector outlets has a mixture ratio of approximately 1.8, followed by a second mixing zone with very high air density, the purpose of which is to minimize the formation of stoichiometric regions and NOx emissions, and to complete the initial rich combustion. Finally, to complete combustion, additional air injections are provided in a third zone to perform a second lean combustion at a mixture ratio of 0.5. Due to the specific characteristics of hydrogen, the traditional RQL geometry for kerosene combustion is not optimal and must be redesigned. Statement of Disclosure

[0015] This disclosure aims to address the various problems mentioned above. To this end, this disclosure relates to an injection assembly configured to perform a staged combustion of a fuel mixture of dihydrogen and air in a combustion chamber of a turbomachine, in order to limit NOx generation and reduce combustion noise, as described in documents WO2023 / 214129 A1 and WO2024 / 052611 A1

[0016] In particular, document WO2024 / 052611 A1 describes an injection assembly for an aircraft turbomachine, the injection assembly having a longitudinal axis and extending between an upstream part and a downstream part, the injection assembly comprising:

[0017] a fuel mixing channel, the fuel mixing channel extending along the longitudinal axis, the fuel mixing channel is externally delimited by a fuel mixing wall, the fuel mixing channel has a fuel mixing inlet and a fuel mixing outlet, the fuel mixing channel is intended to communicate with the combustion chamber at the fuel mixing outlet in order to supply the combustion chamber with a flow of fuel mixing,

[0018] an external air channel, the external air channel having an external air inlet and an external air outlet, said external air channel extends around the fuel mixture channel and is intended to communicate with the combustion chamber at the external air outlet in order to supply the combustion chamber with an external airflow extending around the fuel mixture flow,

[0019] an internal air channel, the internal air channel extends along the longitudinal direction, coaxially with the fuel mixture channel, the internal air channel is delimited by an internal air wall, the internal air channel has an internal air inlet and an internal air outlet, the fuel mixture channel extends around the internal air channel in order to supply the combustion chamber at the level of the internal air outlet with an internal air flow surrounded by the fuel mixture flow (which is preferably annular).

[0020] The solution described in document WO2024 / 052611 Al is particularly satisfactory in the case of jet-in cross-flow hydrogen injection. This disclosure aims to propose an alternative solution, particularly for other types of injection.

[0021] In accordance with this disclosure, the injection assembly further comprises a plurality of fins, the fins extend into the fuel mixture channel between the fuel mixture wall and the internal air wall, each fin contains a through channel extending between a through air inlet and a through air outlet, the through air outlet communicating with the internal air inlet, in order to supply the internal air channel with an internal airflow passing through the through channels.

[0022] Thus, the combustion device imposes fewer constraints on the fuel (dihydrogen) injection device supplying the fuel mixture channel. In particular, it is not necessary to route the internal air channel through the injection device.

[0023] In various embodiments of the combustion device according to the disclosure, one and / or the other of the following additional provisions may optionally be used:

[0024] the fuel mixing channel comprises a first portion and a second portion, the first portion of the fuel mixing channel has a cylindrical shape of revolution in other words the fuel mixing channel extends at the longitudinal axis, the internal air channel extends coaxially to the second portion of the fuel mixing channel and the internal air channel is surrounded by the second portion of the fuel mixing channel (which is preferably annular);

[0025] the second portion of the fuel mixing channel has a substantially tubular shape having an annular cross-section;

[0026] the fins are rigidly fixed to the fuel mixture wall and to the internal air wall;

[0027] the fins are, preferably at least three in number, regularly distributed around the longitudinal axis and are inclined with respect to the longitudinal axis, in order to form a spiral rotating the flow of fuel mixture around the longitudinal axis;

[0028] the internal air wall has a substantially conical portion surrounded by the second portion of the fuel mixing channel and close to the first portion of the fuel mixing channel;

[0029] the injection assembly further includes a fuel injection device, the fuel injection device includes a fuel injection channel having a fuel outlet, the fuel injection channel communicates with the fuel mixture channel via the fuel outlet and the fuel mixture inlet;

[0030] the fuel injection channel extends along a fuel injection axis and the longitudinal axis is in line with the fuel injection axis;

[0031] The injection assembly further includes a combustion air channel, the combustion air channel has a combustion air outlet, extends coaxially to the fuel injection channel at the combustion air outlet and communicates with the fuel mixture channel via the combustion air outlet and the fuel mixture inlet;

[0032] the fuel injection channel includes a fuel throat near the fuel outlet;

[0033] The injection assembly further comprises an intermediate channel extending between an intermediate air inlet and an intermediate air outlet, the intermediate channel communicates with the external air channel via the intermediate air outlet and the external air inlet, the intermediate channel communicates with the external air channel via the intermediate air outlet and the external air inlet, and the intermediate channel communicates with the through channel via the intermediate air outlet and the through air inlet;

[0034] the intermediate channel is substantially tubular and extends coaxially to the longitudinal axis, and the intermediate channel extends around the fuel mixture channel (essentially around the first part of the fuel mixture channel) and is separated from the fuel mixture channel by the fuel mixture wall.

[0035] Since dihydrogen is preferably at a low temperature in the dihydrogen source, the fuel mixture flow is heated by the internal air flow passing through the channels. The fins can therefore form a heat exchanger of heat between the fuel mixture flow and the internal air flow separated from each other by the fins.

[0036] This disclosure further relates to a combustion device comprising the injection assembly and a combustion chamber, the fuel mixture channel communicating with the combustion chamber at the fuel mixture outlet, the external air channel communicating with the combustion chamber at the external air outlet and the internal air channel communicating with the combustion chamber at the internal air outlet. Brief description of the figures

[0037] Other features and advantages of this disclosure will become apparent in the following detailed description, with reference to the accompanying drawings in which:

[0038] [Fig. 1] represents a part of an aircraft turbomachine comprising a combustion device, the combustion device comprising an injection assembly and a combustion chamber,

[0039] [Fig.2] schematically represents at an enlarged scale the area identified II in [Fig.1]. Detailed description of the disclosure

[0040] Figure 1 partially and schematically illustrates a turbomachine 100, particularly for aircraft. The turbomachine 100 has a rotation axis 110 and comprises a compressor 102, combustion devices 1, a high-pressure turbine 104, a first shaft 105, a low-pressure turbine 106 and a second shaft 107.

[0041] The compressor 102 can have several stages; in [Fig. 1] two stages are shown. The first shaft 105 is rotatable about the axis of rotation 110 and connects the high-pressure turbine 104 to the compressor 102. The second shaft 107 is also rotatable about the axis of rotation 110 and connects the low-pressure turbine 106 to a blower (not shown). The second shaft 107 extends partially inside the first shaft 105.

[0042] The turbomachine 100 includes a primary air circuit 108 flowing from upstream to downstream between a primary air inlet 108a and a primary air outlet 108b. Ambient air, forming primary air, enters the primary air circuit 108 through the primary air inlet 108a, and the primary air is then compressed in the compressor 102. The primary air then enters the combustion devices 1, which are regularly arranged around the axis of rotation 110 and positioned between the compressor 102 and the high-pressure turbine 104 along the direction of the axis of rotation 110. In the combustion devices 1, the primary air serves as an oxidizer for the combustion of a fuel. Then, the primary air from each combustion device 1 passes successively through the high-pressure turbine 104 and the low-pressure turbine 106, which it drives. rotating around the axis of rotation 110, before exiting through the primary air outlet 108b. The combustion devices 1 being identical or similar, only one combustion device is detailed below.

[0043] As illustrated in [Fig.2], the combustion device 1 extends between an upstream part 2 and a downstream part 4. The combustion device 1 has a longitudinal axis X. In the illustrated embodiment, the longitudinal axis X is parallel to the axis of rotation 110.

[0044] The combustion device 1 comprises an injection assembly 70 and a combustion chamber 90. The injection assembly 70 includes in particular a fuel injection device 8, a combustion air channel 20, a fuel mixture channel 30, an external air channel 40, an internal air channel 50, through channels 53, an intermediate channel 60.

[0045] The fuel mixture channel 30 extends from the upstream portion 2 to the downstream portion 4 along the longitudinal axis X, between a fuel mixture inlet 31 and a fuel mixture outlet 39. The fuel mixture channel 30 is externally delimited by a fuel mixture wall 34. The fuel mixture channel 30 communicates with the combustion chamber 90 at the fuel mixture outlet 39 in order to supply the combustion chamber 90 with a fuel mixture flow 32. The fuel mixture flow 32 is burned in the combustion chamber 90, creating a primary combustion represented by the primary combustion flame 92.

[0046] Preferably, a portion of the fuel mixture channel 30 forming a diffuser along the direction of the fuel mixture flow 32 is present at the fuel mixture outlet 39. In a particular embodiment, the diffusion of the fuel mixture flow 32 can be achieved by a section diverging downstream of the fuel mixture channel 30 at the fuel mixture outlet 39. Other shapes of the external air channel 40 at the external air outlet 49 would also be possible, as illustrated in particular in document WO2023 / 057722A1.

[0047] The fuel mixture wall 34 is preferably tapered at the fuel mixture outlet 39 to reduce the presence of recirculation vortices in the combustion chamber 90 near the fuel mixture wall 34 and thus prevent the flame from catching on it.

[0048] The gaseous fuel injection device 8 comprises a pressurized dihydrogen source 6 and a fuel injection channel 10. The fuel injection channel 10 is delimited by a fuel injection wall 14. The fuel injection channel 10 extends from the upstream portion 2 to the downstream portion 4 along a fuel injection axis Y between a fuel inlet 11 and a fuel outlet 19. The fuel injection channel 10 is supplied with fuel (dihydrogen) at the fuel inlet 11 by the pressurized dihydrogen source 6. The fuel injection channel 10 communicates with the fuel mixture channel 30 via the fuel outlet 19 and the fuel mixture inlet 31.

[0049] The fuel injection channel 10 includes a fuel venturi near the fuel outlet 19. The fuel venturi comprises successively, from the upstream portion 2 to the downstream portion 4, a converging fuel portion 16, a fuel throat 17 and a diverging fuel portion 18. The converging fuel portion 16 is substantially conical and adjacent to the fuel throat 17 and the diverging fuel portion 18 is substantially conical and adjacent to the fuel throat 17. In the embodiment illustrated in [Fig. 2], the fuel venturi is integrated as a projection inside the fuel wall 14.

[0050] The fuel injection channel 10 further includes a settling cavity 15 between the fuel inlet 11 and the fuel throat 17. In particular, the settling cavity 15 directly feeds the fuel throat 17; in other words, the settling cavity 15 opens into the fuel throat 17. The settling cavity has a cross-section significantly larger (at least 5 times, preferably at least 10 times) than the cross-section at the fuel throat 17. The fuel injection channel 10 guides a fuel flow 12 extending along the fuel injection axis Y. The fuel flow 12 is substantially cylindrical, extending along the fuel injection axis Y and around the fuel injection axis Y; in other words, the fuel flow is central. The fuel flow 12 exits the fuel injection channel 10 at the fuel outlet 19.Before exiting the fuel injection channel 10, the fuel flow 12 is accelerated by the fuel venturi. The fuel flow 12 then enters the fuel mixture channel 30 at the fuel mixture inlet 31.

[0051] The combustion air channel 20 has a combustion air inlet 21 and a combustion air outlet 19. The combustion air inlet 21 is supplied with pressurized air by the compressor 102. The combustion air channel 20 is tubular and extends coaxially with the fuel injection channel 10 (around the fuel injection channel 10), particularly at the combustion air outlet 29. The combustion air channel 20 is internally delimited by the fuel injection wall 14, which separates the combustion air channel 20 from the fuel injection channel 10. The combustion air channel 20 is externally delimited by a combustion air wall 24. The combustion air channel 20 communicates with the fuel mixture channel 30 by via the combustion air outlet 29 and the fuel mixture inlet 31.

[0052] The combustion air channel 20 guides a combustion air flow 22 extending substantially along the direction of the fuel injection axis Y, coaxially with the fuel flow 12. The combustion air flow 22 exits the combustion air channel 20 at the combustion air outlet 29 and enters the fuel mixture channel 30 at the fuel mixture inlet 31. In the first embodiment, as illustrated in [Fig.2], the longitudinal axis X extends in line with the fuel injection axis Y.

[0053] The combustion device 1 includes an optional damper 28 located in the combustion air channel 20. The damper 28 is movable between a first position (shown as a solid line) and a second position (shown as a dashed line) in order to vary the cross-section of the combustion air channel 20 between a first cross-section and a second cross-section smaller than the first, so that the combustion air flow 22 can be adjusted. Of course, the damper 28 can be arranged in many other positions between the first and second positions, in order to fine-tune the combustion air flow 22. The damper 28 is preferably movable in translation along the direction of the fuel injection axis Y, as illustrated by the double arrow 27. In the illustrated embodiment, the damper 28 has a tubular shape.

[0054] The fuel flow 12 and the combustion air flow 22 mix in the fuel mixing channel 30. The fuel flow 12 at the fuel outlet 19 preferably reaches a speed between 0.4 Mach and 1 Mach, thanks to a fuel pressure drop of between 30% and 50%, preferably between 35% and 45%. The fuel pressure drop can be determined by measuring the pressure difference in the fuel injection channel 10 between the fuel inlet 11 and the fuel outlet 19, and dividing this pressure difference by the pressure measured at the fuel inlet 11.

[0055] Furthermore, the combustion air pressure drop between the combustion air inlet 21 and the combustion air outlet 29 is between 4% and 20%, preferably between 4% and 10%. The combustion air pressure drop can be determined by measuring the pressure difference in the combustion air duct 20 between the combustion air inlet 21 and the combustion air outlet 29, and dividing this pressure difference by the pressure at the combustion air inlet 21.

[0056] The injection assembly 70 has a pressure drop ratio equal to the combustion air pressure drop divided by the injection air pressure drop. The pressure drop ratio is preferably between 3 and 10.

[0057] Fuel pressure drop and combustion air pressure drop, in particular the ratio between fuel pressure drop and combustion air pressure drop (in other words the pressure drop ratio) are important to ensure optimal performance and minimum energy consumption.

[0058] Pressure losses correspond to energy losses caused by friction, changes in direction or cross-section, turbulence, and other obstacles to fluid movement. These various elements can be addressed during the design of the injection assembly 70 in order to obtain the desired pressure losses.

[0059] The change in cross-section due to the combustion throat 17 creates a pressure drop. Furthermore, when gaseous hydrogen flows through the fuel injection channel and when combustion air flows through the combustion air channel, friction with the walls creates pressure drops. In particular, the roughness of the walls can be adjusted to vary the pressure drop due to friction. It is also possible, for example, to modify the pressure drop by the presence of obstacles or asperities in the combustion air channel 20, particularly on the walls of the combustion air channel.

[0060] Given the high velocity of the fuel flow 12 at the outlet of the fuel injection channel 10, the combustion air flow 22 is drawn in and then mixed with the fuel flow 12 in the fuel mixing channel 30. The fuel mixing channel 30 includes a fuel mixing venturi near the fuel mixing inlet 31. The fuel mixing venturi comprises, successively from the upstream portion 2 to the downstream portion 4, a converging mixing portion 36, a fuel mixing throat 37, and a diverging mixing portion 38. The converging mixing portion 36 is substantially conical and adjacent to the fuel mixing throat 37, and the diverging mixing portion 38 is substantially conical and adjacent to the fuel mixing throat 37. In the embodiment illustrated in [Fig. 2], the fuel mixing venturi is integrated as a projection inside the fuel mixing wall 34.

[0061] The fuel (hydrogen) may have a temperature close to 300K at the fuel outlet 19 or a lower temperature (preferably between 200K and 250K), in order to cool the walls of the fuel mixture channel 30, the walls of the fuel mixture channel 30 being likely to be heated in particular by the combustion of the fuel mixture stream 32 in the combustion chamber 90.

[0062] Injecting hydrogen at a low temperature (preferably between 200K and 250K) reduces the production of nitrogen oxide during the combustion of the rich fuel mixture stream 32 in the combustion chamber 90.

[0063] The external air channel 40 extends from the upstream portion 2 to the downstream portion 4 along the longitudinal axis X, between an external air inlet 41 and an external air outlet 49. The external air channel 40 is substantially tubular and extends coaxially with the longitudinal axis X. The external air channel 40 extends around the second portion 30b of the fuel mixture channel 30 and is separated from the second portion 30b of the fuel mixture channel 30 by the fuel mixture wall 34. The external air channel 40 communicates with the combustion chamber 90 at the external air outlet 49 in order to supply the combustion chamber 90 with an external airflow 42 extending around the fuel mixture flow 32.

[0064] Preferably, a portion of the external air channel 40 forming a diffuser along the direction of the external airflow 42 is present at the external air outlet 49. In a particular embodiment, the diffusion of the external airflow 42 can be achieved by a section diverging downstream of the external air channel 40 at the external air outlet 49. Other shapes of the external air channel 40 at the external air outlet 49 would also be possible, as illustrated in particular in document WO2023 / 057722A1.

[0065] An external air auger 45 is preferably disposed in the external channel 40, so as to rotate the external airflow 42 around the longitudinal axis X at the same time as the external airflow 42 moves from the upstream part 2 to the downstream part 4 along the direction of the longitudinal axis X. In other words, the external airflow 42 has a helical movement along the longitudinal axis X between the external air auger 45 and the combustion chamber 90.

[0066] The internal air channel 50 extends along the longitudinal axis X; in other words, the internal air channel 50 is central. The internal channel 50 is delimited (externally) by an internal air wall 54. The internal air wall 54 has a portion 54a of substantially conical shape at the internal air inlet 51. The internal air channel 50 extends along the longitudinal direction X between an internal air inlet 51 and an internal air outlet 59.

[0067] The fuel mixing channel 30 comprises successively a first portion 30a and a second portion 30b. The first portion 30a of the fuel mixing channel 30 extends from the fuel mixing inlet 31 to an upstream end of the internal air wall 54. The first portion 30a of the fuel mixing channel 30 has a cylindrical shape of revolution; therefore, the first portion 30a of the fuel mixing channel 30 extends along the longitudinal axis X, in other words, the first portion 30a of the fuel mixing channel 30 is central. The internal air channel 50 extends coaxially with the second portion 30b of the fuel mixing channel 30. The internal air channel 50 is surrounded by the second portion 30b of the fuel mixing channel 30 and separated from the channel. fuel mixture 30 through the internal air wall 54. The second portion 30b of the fuel mixture channel 30 has a substantially tubular shape having an annular cross-section.

[0068] The through channels 53 each extend between a through air inlet 53a and a through air outlet 53b. The through air outlet 53b communicates with the internal air inlet 51, in order to supply the internal air channel 50 with an internal airflow 52 passing through the through channels 53. The internal air channel 50 communicates with the combustion chamber 90 at the internal air outlet 59, in order to supply the combustion chamber 90 with the internal airflow 52.

[0069] There is a heat exchange between the internal airflow 52 circulating in the through channels 53, inside the fins 55, and the fuel mixture flow 32 circulating in the fuel mixture channel 30, outside the fins 55. The fuel mixture flow 32 is heated by the internal airflow 52.

[0070] Preferably, a portion of the internal air channel 50, forming a diffuser along the direction of the internal airflow 52, ​​is present at the internal air outlet 59. In a particular embodiment, the diffusion of the internal airflow 52 can be achieved by a section diverging downstream of the internal air channel 50 at the internal air outlet 59. Other shapes of the internal air channel 50 at the internal air outlet 59 would also be possible, as illustrated in particular in document WO2023 / 057722A1.

[0071] One, the other or both of the external air channel 40 at the external outlet 49 and the internal air channel 50 at the internal air outlet 59 may have a divergent section.

[0072] The internal air wall 54 is preferably tapered at the internal air outlet 59 to reduce the presence of recirculation vortices in the combustion chamber 90 near the internal air wall 54 and thus prevent the flame from catching on it.

[0073] The intermediate channel 60 extends along the longitudinal axis X between an intermediate air inlet 61 and an intermediate air outlet 69. The intermediate air inlet 61 is supplied with pressurized air by the compressor 102. The primary air circuit 108 splits between the combustion air channel 20 and the intermediate air channel 60 at the combustion air inlet 21 and the intermediate air inlet 61. Thus, the intermediate air channel 60 is supplied by an intermediate airflow 62. The intermediate channel 60 is substantially tubular, circular in cross-section, and extends coaxially with the longitudinal axis X. The intermediate channel 60 extends around the fuel mixture channel 30 (essentially around the first part 30a of the fuel mixture channel 30) and is separated from the fuel mixture channel 30 by the fuel mixture wall 34. The channel air The intermediate duct 60 is delimited (externally) by a tubular intermediate air wall 64. The external air wall 44 extends in line with the intermediate air wall 64, such that the intermediate air wall 64 and the external air wall 44 form two successive portions of a single wall. The intermediate airflow 62 splits into the external airflow 42 and the internal airflow 52 at the external air inlet 41 and the through air inlets 53a. Alternatively, the intermediate air duct 60 could be replaced by a radial supply of pressurized air from the compressor 102 via the external air inlet 41 and the through air inlets 53a.

[0074] It will be noted that retaining tabs extend in the intermediate channel 60 between the fuel mixture wall 34 and the intermediate air wall 64. The retaining tabs are distributed around the longitudinal axis X and are in the form of thin plates extending radially from the longitudinal axis X, in order to minimize their effect on the intermediate air flow 62.

[0075] More specifically, the combustion device 1 further comprises a plurality of fins 55. The fins 55 extend into the fuel mixture channel 30 between the fuel mixture wall 34 and the internal air wall 54. Each of the fins 55 contains one of the through channels 53.

[0076] The fins 55 are rigidly fixed to the fuel mixture wall 34 and to the internal air wall 54, in order to hold the internal wall 54.

[0077] The fins 55 are evenly distributed around the longitudinal axis X and are inclined with respect to the longitudinal axis X, in order to rotate the fuel mixture flow 32 around the longitudinal axis X. Thus, the fins 55 perform a twisting function. In other words, the fins 35 rotate the fuel mixture flow 32 around the longitudinal axis X at the same time as the fuel mixture flow 32 moves from the upstream part 2 to the downstream part 4 along the direction of the longitudinal axis X. Downstream of the fins 55, the fuel mixture flow 32 therefore exhibits a helical motion around the longitudinal axis X.

[0078] Thus, the fuel mixture channel 30 (formed by the second portion 30b) extends around the internal air channel 50 at the fuel mixture outlet 39 in order to supply the combustion chamber 90 with the tubular fuel mixture flow 32 surrounding the internal air flow 52. The fuel mixture flow 32 is burned in the combustion chamber 90 creating a first combustion 92 represented by the substantially tubular first combustion flame 92.

[0079] The fuel mixture stream 32 is rich; preferably, the fuel mixture stream 32 has a proportion between the fuel stream 12 and the combustion air stream 22 that includes at least 10% excess fuel (dihydrogen). relative to the combustion air flow 22 so that all the dihydrogen is burned by the first combustion 92 (richness greater than or equal to 1.1).

[0080] The portion of fuel (dihydrogen) which is not burned by the first combustion 92 is burned in the combustion chamber 90, on the one hand with the external airflow 42 and on the other hand with the internal airflow 52, ​​creating a second combustion 94 represented by a second combustion flame 94 of also substantially tubular shape.

[0081] Of course, disclosure is in no way limited to the embodiment described by way of illustration, not limitation. For example, the combustion air channel 20 or the external air channel 40 could be different and include one or more annular or axial spirals. Reference may be made, in particular, to document FR2208857 A1 for further details on this subject.

Claims

1. Demands Injection assembly (70) for an aircraft turbomachine, the injection assembly (70) having a longitudinal axis (X) and extending between an upstream part (2) and a downstream part (4), the injection assembly comprising: a fuel mixing channel (30), the fuel mixing channel (30) extending along the longitudinal axis (X), the fuel mixing channel (30) is externally delimited by a fuel mixing wall (34), the fuel mixing channel (30) has a fuel mixing inlet (31) and a fuel mixing outlet (39), the fuel mixing channel (30) is intended to communicate with the combustion chamber (90) at the fuel mixing outlet (39) in order to supply the combustion chamber (90) with a fuel mixing flow (32), an external air channel (40), the external air channel (40) having an external air inlet (41) and an external air outlet (49), said external air channel (40) extends around the fuel mixture channel (30) and is intended to communicate with the combustion chamber (90) at the external air outlet (49) in order to supply the combustion chamber (90) with an external airflow (42) extending around the fuel mixture flow (32), an internal air channel (50), the internal air channel (50) extending in the longitudinal direction (X), coaxially with the fuel mixture channel (30), the internal air channel (50) is delimited by an internal air wall (54), the internal air channel (50) has an internal air inlet (51) and an internal air outlet (59), the fuel mixture channel (30) extends around the internal air channel (50) in order to supply the combustion chamber (90) at the internal air outlet (59) with an internal airflow (52) surrounded by the fuel mixture flow (32), in which the injection assembly (70) further comprises a plurality of fins (55), the fins (55) extending in the fuel mixture channel (30) between the fuel mixture wall (34) and the internal air wall (54), the fins (55) each contain a through channel (53) extending between a through air inlet (53a) and a through air outlet (53b), the through air outlet (53b)。 communicating with the internal air inlet (51), in order to supply the internal air channel (50) with an internal airflow (52) passing through the through channels (53).

2. Injection assembly (70) according to claim 1 in which: the fuel mixture channel (30) comprises a first portion (30a) and a second portion (30b), the first portion (30a) of the fuel mixture channel (30) has a cylindrical shape of revolution, the internal air channel (50) extends coaxially to the second portion (30b) of the fuel mixture channel (30) and the internal air channel (50) is surrounded by the second portion (30b) of the fuel mixture channel (30).

3. Injection assembly (70) according to the preceding claim in which the second portion (30b) of the fuel mixture channel (30) has a substantially tubular shape having an annular cross-section.

4. Injection assembly (70) according to any one of the preceding claims in which the fins (55) are rigidly fixed to the fuel mixture wall (34) and to the internal air wall (54).

5. Injection assembly (70) according to any one of the preceding claims wherein the fins (55) are regularly distributed around the longitudinal axis (X) and are inclined with respect to the longitudinal axis (X), in order to form a spiral rotating the flow of fuel mixture (32) around the longitudinal axis (X).

6. Injection assembly (70) according to any one of the preceding claims in which the internal air wall has a substantially conical portion (54a) surrounded by the second portion (30b) of the fuel mixture channel (30) and in close proximity to the first portion (30a) of the fuel mixture channel (30).

7. Injection assembly (70) according to any one of the preceding claims wherein the injection assembly (70) further comprises a fuel injection device (8), the fuel injection device (8) comprises a fuel injection channel (10) having a fuel outlet (19), the fuel injection channel (10) communicates with the fuel mixture channel (30) via the fuel outlet (19) and the fuel mixture inlet (31).

8. Injection assembly (70) according to the preceding claim in which the fuel injection channel (10) extends along a fuel injection axis (Y) and the longitudinal axis (X) is in the continuation of the fuel injection axis (Y).

9. Injection assembly (70) according to claim 7 or claim 8 wherein the injection assembly (70) further comprises a combustion air channel (20), the combustion air channel (20) having a combustion air outlet (29), extending coaxially to the fuel injection channel (10) at the combustion air outlet (29) and communicating with the fuel mixture channel (30) via the combustion air outlet (29) and the fuel mixture inlet (31).

10. Injection assembly (70) according to any one of the preceding claims wherein: the injection assembly (70) further comprises an intermediate channel (60) extending between an intermediate air inlet (61) and an intermediate air outlet (69), the intermediate channel (60) communicates with the external air channel (40) via the intermediate air outlet (69) and the external air inlet (41), the intermediate channel (60) communicates with the external air channel (40) via the intermediate air outlet (69) and the external air inlet (41), and the intermediate channel (60) communicates with the through channel (53) via the intermediate air outlet (69) and the through air inlet (53a).

11. Combustion device (1) comprising an injection assembly (70) according to any one of the preceding claims and a combustion chamber (90), the fuel mixture channel (30) communicating with the combustion chamber (90) at the fuel mixture outlet (39), the external air channel (40) communicating with the combustion chamber (90) at the external air outlet (49) and the internal air channel (50) communicating with the combustion chamber (90) at the internal air outlet (59).

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