WO2023057722A1

WO2023057722A1 - Device for injecting dihydrogen and air

Info

Publication number: WO2023057722A1
Application number: PCT/FR2022/051883
Authority: WO
Inventors: Stéphane Raphaël Yves RICHARD; Christophe Nicolas Henri VIGUIER; Sylvain MARRAGOU; Thierry Schuller
Original assignee: Centre National De La Recherche Scientifique; Safran Helicopter Engines; Universite De Toulouse Iii - Paul Sabatier
Priority date: 2021-10-08
Filing date: 2022-10-05
Publication date: 2023-04-13
Also published as: CA3233988A1

Abstract

The invention relates to a dihydrogen injection device (2) having a longitudinal axis (X), intended to be mounted on an annular base of an annular combustion chamber (4) of a turbomachine, comprising an inner channel (6) for circulating dihydrogen, and an annular outer channel (8) for circulating a mixture at least comprising air, the inner channel (6) and the annular outer channel (8) being coaxial, an inner swirler (14) being provided in the inner channel (6) and an outer swirler (28) being provided in the annular outer channel (8), a downstream end (16) of the inner channel (6) being arranged upstream, at a distance r, from a downstream end (24) of the annular outer channel (8). Such combustion of dihydrogen makes it possible to eliminate carbon-containing polluting emissions such as carbon monoxide, unburned hydrocarbons or fine particles and smoke particles.

Description

Title: Dihydrogen and air injection device

Technical area

This document concerns turbomachines whose combustion chamber is fed by separate injections of dihydrogen and air.

Prior technique

[0002] The aeronautical sector faces major environmental challenges. The advantage of having recourse to combustion using dihydrogen rather than the use of kerosene is increasingly strong because this combustion of dihydrogen would make it possible to avoid carbon dioxide emissions (CO2) and carbon pollutants such as as carbon monoxide, unburned hydrocarbons or even fine and smoked particles.

[0003] A principle of micro-mixture burners of air and dihydrogen is known. However, such burners do not guarantee the thermal resistance of a pierced wall or the absence of flashback in the dihydrogen injection device. These burners also have a complex geometry system. Such burners have a high production cost, a high pressure drop and these burners are specific to a given combustion chamber architecture.

[0004] Indeed, the combustion of dihydrogen gives rise to various problems. Thus, risks of flashback in the injection device can occur for systems operating with mixtures of dihydrogen and air. This can damage the combustion chamber and pose serious safety concerns. Finally, the combustion of dihydrogen generates high thermal loads towards the walls of this combustion chamber, which tends to reduce its lifetime. High gas temperatures and nitrogen oxide emissions are produced. These gas and nitrogen oxide emission temperatures are higher than those produced by kerosene flames, at equivalent richness. This is, moreover, hardly compatible with current standards.

Summary

This document relates to a longitudinal axis dihydrogen injection device intended to be mounted on an annular bottom of an annular combustion chamber of a turbomachine comprising an internal channel for the circulation of dihydrogen and an external annular channel circulation of a mixture comprising at least air, the internal channel and the external annular channel being coaxial, an internal swirl being housed in the internal channel and an external swirling being housed in the external annular channel, and wherein a downstream end of the inner channel is arranged upstream, at a distance r, from a downstream end of the outer annular channel.

[0006] This device makes it possible to produce a dihydrogen/air flame which can be used in turbomachines which makes it possible both to produce low levels of nitrogen oxide emissions, a reduced thermal load on the combustion chamber and the injector as well as eliminating the risk of flashback. Moreover, this injector has the particularity of being both simple to produce and easily adaptable to existing turbomachines running on kerosene.

[0007] In general, a spin makes it possible to put a flow into rotation. The integration of an internal spin in the internal channel makes it possible to create a recirculation zone for a flow of dihydrogen crossing said internal channel and preventing the combustion of the air and dihydrogen mixture from coming to stabilize on the downstream end of the internal channel . By recirculation zone is meant a zone generating a centrifugation effect with a depression inside capable of producing an axial velocity component of the flow on average negative with respect to a main direction of the flow. This recirculation zone is similar to that generated inside a whirlpool in which air is sucked. The internal recirculation zone blocks part of the flow of dihydrogen along the longitudinal axis of said internal channel generating in an outlet section of this internal channel significant overspeeds near the walls of the internal channel with respect to a flow with uniform axial flow rate. The rotation of the dihydrogen of the internal channel makes it possible to avoid hanging the flame on the downstream ends of the internal channel by stabilizing it aerodynamically above the internal channel. The downstream end of the internal channel being arranged upstream at a distance r, this further prevents the flame from catching on the lips of the internal channel. This rotation of the dihydrogen in the internal channel avoids the installation of a complex cooling device for the dihydrogen injection device. Thus, the cost and mass of the dihydrogen injection device are improved. This dihydrogen injection device produces limited pressure drops compared to other liquid injection devices using kerosene as in the prior art. This dihydrogen injection device has a simple geometry, a low production cost and adapts to existing combustion chamber architectures.

[0008] This remote flame stabilization facilitates partial mixing between the mixture containing at least air with the dihydrogen exiting the internal channel, upstream of the flame, and avoiding any risk of flame rising in said channel internal and the external channel, also called "flashback" in English. This makes it possible to achieve a combustion depleted of dihydrogen in the combustion chamber. These measures thus tends to greatly reduce the combustion temperatures and the nitrogen oxides emitted. This guarantees the integrity of a combustion chamber.

The positioning of the downstream end of the internal channel upstream of the downstream end of the annular channel, distance denoted r in Figure 2, external fulfills two functions. It optimizes the mixture between hydrogen and air. It also makes it possible to widen the operating range where the flame is detached by moving back the central dihydrogen introduction zone in relation to the aerodynamic stabilization zone of the flame.

[0010] The internal channel may be a tubular central channel.

[0011] At least the internal twist of the internal channel may have a helical shape.

[0012] This helical shape makes it possible to improve the aerodynamics of the flow of dihydrogen passing through the internal spin.

[0013] The inner swirler can be arranged along the longitudinal axis downstream of the outer swirler.

[0014] A rate of rotation S generated by the internal spin of the internal channel, defined as a ratio between a tangential speed and a delivery speed along the longitudinal axis of a hydrogen flow at the outlet of the internal spin, can be equal or greater than 0.6.

[0015] These values of the rate of rotation S, which is a dimensionless number, make it possible to obtain flames having a rotational movement with respect to the longitudinal axis which are detached from the internal channel.

The internal spin of the internal channel can be arranged upstream, at a distance l, from the downstream end of the internal channel.

The internal channel may have an internal diameter d and the external annular channel may have an internal diameter D such that a D/d ratio is between 3 and 10.

[0018] This optimized D/d ratio makes it possible to operate in a dihydrogen-poor regime.

[0019] A thickness of a wall of the internal channel e is such that an e/d ratio can be between 0.05 and 0.7.

[0020] An l/d ratio can be between 1 and 3.

[0021] The minimum distance l _min is equal to 1 d so that a central recirculation zone enters the internal channel. The range chosen for l/d makes it possible to obtain a good compromise and a rotation rate S sufficient to correctly rotate the flame.

The distance r can be between 0.05D and 0.5D. [0023] There is an optimum value for the distance r which depends on the diameter D of the outer channel. If this distance r is too high, the recirculation zone becomes unstable. The range of values chosen for r is optimized so as to obtain a stable recirculation zone.

This distance r relative to the downstream end of the outer annular channel makes it possible to increase the operating range where the flame is detached by moving back a dihydrogen introduction zone relative to the aerodynamic stabilization zone of the flame. .

The external spin of the external annular channel can be arranged at an upstream end of said external annular channel, at a distance L from the downstream end of the external annular channel.

The distance L can be between 1D and 5D.

[0027] The rate of rotation S can be greater than 0.6, a flow rate Ui of the dihydrogen in the internal channel being greater than a critical value Ui, _c and verifying the following relationship:

Or :

- P is a pressure in the annular combustion chamber;

- T _a is an air temperature in Kelvin in the external channel;

- p between 1 and 1.5 is a factor depending on the type of auger used;

- So=O.6, P _o =1 bar, T _a o=3OO K and Ui, _c o=18 m/s.

This critical value Ui, _c ensures that the flame formed at the outlet of the injection device is detached from the downstream ends of the internal channel for a wide range of engine operation.

The mixture may be air.

This document relates to an assembly comprising the device of the aforementioned type, in which the internal channel, fluidly connected to means for supplying dihydrogen, comprises the internal swirler configured to rotate said dihydrogen, and the external annular channel , fluidly connected to air supply means, comprises the external swirler configured to rotate said air.

Brief description of the drawings [0031] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the appended drawings, in which:

Fig. 1

[0032] [Fig. 1] shows a turbomachine comprising a dihydrogen injection device arranged in an annular bottom of an annular combustion chamber according to three configurations.

Fig. 2

[0033] [Fig. 2] shows the hydrogen injection device according to the invention.

Fig. 3

[0034] [Fig. 3] schematically shows the formation of a recirculation zone which penetrates the dihydrogen injection device and a flame at the outlet of the dihydrogen injection device.

Fig. 4

[0035] [Fig. 4] shows a plurality of possible configurations (FIGS. A, B, C, D, E, F, G, H) of internal channel, according to the invention.

Fig. 5

[0036] [Fig. 5] shows a plurality of possible configurations (figures. A, B, C, D, E) of the downstream end of the outer annular channel, according to the invention.

detailed description

This document relates to a dihydrogen injection device 2 intended to be mounted on an annular bottom of an annular combustion chamber 4 of a turbomachine. This dihydrogen injection device 2 is used in a lean dihydrogen combustion configuration such that the flame temperatures and the formation of nitrogen oxide are reduced. It is said that the injection device is lean when there is excess oxygen in relation to combustion taking place at stoichiometry between dihydrogen and air and that the injection system is rich when there is dihydrogen in excess with respect to this combustion at stoichiometry. Combustion at stoichiometry is defined as that for which there is the right number of hydrogen and oxygen atoms necessary to consume all the fuel and only water remains in the combustion products. It is in the context of lean combustion in dihydrogen that the present invention is placed.

As illustrated in Figure 1, three locations of said dihydrogen injection device 2 are possible depending on the orientation of the annular bottom of the chamber combustion ring 4: either the combustion chamber is oriented substantially along a longitudinal axis, with the bottom of the chamber located towards the front of the engine called the direct chamber or with the bottom of the chamber located towards the rear of the engine called the flow chamber reversed as illustrated in FIG. 1, or the combustion chamber is transverse to said longitudinal axis X. In all cases, the dihydrogen injection device 2 is located between the compressor and the high-pressure turbine, on the annular bottom of the annular combustion chamber 4 or on an outer shroud.

As illustrated in Figure 2, said dihydrogen injection device comprises an internal channel 6 and an external annular channel 8. The internal channel 6 and the external annular channel 8 are coaxial.

A first gas is injected from an inlet 10 located at an upstream end of the internal channel 6. This first gas is dihydrogen 12. The internal channel 6 has an internal diameter d. The choice of the internal diameter d of the channel depends on a desired thermal power. A thickness of an inner channel wall e is half the difference of an outer diameter of the inner channel and an inner diameter of the inner channel d. An e/d ratio is between 0.05 and 0.7.

This internal channel 6 comprises an internal twist 14 configured to rotate a flow of dihydrogen 12 around a longitudinal axis X. Said internal twist 14 of the internal channel 6 is arranged at a distance l from a downstream end 16 of the internal channel. The distance l between the downstream end 16 of the internal channel 6 and a downstream end 18 of the internal spinner 14 is between 1d and 5d. As illustrated in FIG. 3, a space is thus left between the internal swirler 14 and the downstream end 18 of the internal channel 6 so that a central recirculation zone 20 can be installed. The recirculation zone is a region around the longitudinal axis X of the injection device where an axial component of the flow is on average negative with respect to a main direction of the flow. This recirculation zone 20 is generated by a depression created inside the rotational movement of the flow. This depression is due to the centrifugation effect induced by this rotation of the flow. The recirculation zone 20 is similar to that generated inside a vortex in which air is sucked. In this document, the recirculation zone 20 is configured to penetrate inside the internal channel blocking part of the section of the downstream end 16 of the internal channel 6 and producing an acceleration of the flow at the periphery. This repels a flame 22 formed at the outlet of the injection device and sets it in rotation.

[0042] The internal swirl 14 may, for example, comprise a helical part with a suitable helix pitch. This helix pitch is configured to define a positioning of the flame 22 at the outlet of the injection device 2, to minimize polluting emissions and define a thermal injection device. This helical part rotates the flow of dihydrogen with a rate of rotation characterized by a dimensionless number S. This rate of rotation S is defined as a ratio of an angular momentum to the product of a radius of the channel multiplied by an impulse of the flow of dihydrogen 12 set in rotation, according to the following formula:

where G _e is the angular momentum of the flow in an axial direction, G _z is the momentum of the flow in the axial direction and d is the diameter of the channel. Approximate expressions are generally used to estimate G _e and G _z based on the tangential and axial velocities of the flow set in rotation in the channel. In this case S corresponds to the ratio of a tangential speed divided by an axial speed. The tangential speed corresponds to a rotational component of the speed with respect to the injection axis.

A rate of blockage of the flow of dihydrogen 12 in the internal channel 6 is established so as to be high enough to repel the flame 22 forming at a downstream end 24 of the outer annular channel 8. The blockage rate represents a ratio between a section occupied by the recirculation zone 20 rising inside the dihydrogen injection device 12 at the level of the downstream end 16 of the internal channel 6 with respect to a passage section of the internal channel 6. This blocking rate depends on the shape of the recirculation zone 20. More specifically, it is an aerodynamic element which depends on the dimensional parameters of the dihydrogen injection device 2. The higher an l/d ratio, the greater the distance d depth of the internal swirler 14 with respect to the diameter is high and the more a high value can be chosen for the rate of rotation S by modifying the geometry of the internal swirler 14. The rate of rotation S is at least equal to 0.6 and an l/d ratio is between 1 and 3. As illustrated in FIG. 4, the downstream end 16 of the internal channel 6 can comprise variable thicknesses as well as different shapes.

In a first embodiment illustrated in Figure 4A, the downstream end 16 of the internal channel 6 has a straight and longitudinal wall.

In a second embodiment illustrated in Figure 4B, the downstream end 16 of the internal channel 6 has a flare shape. This downstream end 16 is configured to modify the flow of the internal channel 6 near the wall of the end 16.

In a third embodiment illustrated in Figure 4C, the downstream end 16 of the internal channel 6 has an outward cap effect. This downstream end 16 is configured to modify the flow of the external channel 8 near the wall of the end 16. In a fourth embodiment illustrated in Figure 4D, the downstream end 16 of the internal channel 6 has a section which increases downstream. This fourth type of downstream end is configured to promote the increase in the rate of rotation S in the internal channel 6 containing the dihydrogen 12. Due to this configuration, the axial speed is reduced and the tangential speed is increased, hence the increase in the rate of rotation S. This downstream end 16 is configured to modify the flow of the internal channel 6 near the wall of the end 16 as well as the flow of the external channel 8 near the wall of the end 16.

In a fifth embodiment illustrated in FIG. 4E, a thickness corresponding to a transverse dimension of a wall of the internal channel 6 is lower or greater than that in the first embodiment.

In a sixth embodiment illustrated in Figure 4F, the downstream end 16 of the internal channel 6 has a bevel effect. This downstream end 16 is configured to modify the flow of the external channel 8 near the wall of the end 16.

In a seventh embodiment illustrated in FIG. 4G, the downstream end 16 of the internal channel 6 has an inward cap effect. This downstream end 16 is configured to modify the flow of the internal channel 6 near the wall of the end 16.

In an eighth embodiment illustrated in FIG. 4H, the downstream end 16 comprises a section which is reduced downstream. This downstream end 16 is configured to modify the flow of the internal channel 6 near the wall of the end 16 as well as the flow of the external channel 8 near the wall of the end 16.

[0052] As illustrated in Figure 1, the downstream end 16 of the internal channel 6 is arranged upstream with respect to the downstream end 24 of the external annular channel 8. The downstream end 24 of the external annular channel 8 is arranged at a distance r from the downstream end 16 of the internal channel 6. This external annular channel 8 has an internal diameter D, such that a ratio D/d with the diameter d of the internal channel 6 is between 3 and 10.

The outer annular channel 8 is configured to receive a second gas comprising air or an air and dihydrogen mixture. This gas enters the outer annular channel through an inlet 26 arranged upstream of said outer annular channel.

[0054] A section ratio between the internal diameter d of the internal channel 6 and the internal diameter D of the external annular channel 8 depends: i/ on the mixing ratio between the air and the desired hydrogen, and ii/ on the flow rate Ui dihydrogen in the internal channel. In this document, operation in a dihydrogen-lean regime requires that this D/d ratio be between 3 and 10.

An outer spinner 28 is housed at an upstream end 30 of the outer annular channel 8. This outer spinner 28 is annular. This external spin 28 can be radial. This annular external spin 28 is arranged at a distance L from the downstream end 36 of the external annular channel 8. This distance L is between 1D and 5D. The fuel is then rotated in the center by the internal spinner 14 while the air or the mixture containing at least air is rotated around by the outer spinner 28. This generates a vortex assembly.

As illustrated in Figure 5, the outer annular channel 8 can have different shapes.

In a particular embodiment illustrated in Figure 5A, the outer annular channel 8 comprises a first annular channel 8 and a second annular channel 32. The first annular channel 8 corresponds to the outer annular channel 8. This first annular channel 8 begins at a downstream end 36 of the outer swirler 28 and opens upstream from the downstream end 30 of the outer swirler 28. The second annular channel 32 has an internal diameter greater than the internal diameter of the first annular channel 8. This second annular channel 32 begins at the downstream end 36 of the outer swirler 28 and emerges upstream from the downstream end 16 of the inner channel 6.

In a particular embodiment illustrated in Figure 5B, the downstream end 24 of the outer annular channel 8 has a section which increases downstream. This downstream end 24 is configured to modify the flow of the outer annular channel 8 near the wall of the end 24.

In a particular embodiment illustrated in FIG. 5C, the downstream end 24 of the outer annular channel 8 has a section which is reduced downstream. This downstream end 24 is configured to modify the flow of the outer annular channel 8 near the wall of the end 24.

In a particular embodiment illustrated in FIG. 5D, the distance L can be modified.

In a particular embodiment illustrated in FIG. 5E, the external annular channel 8 comprises a single annular channel, the flow of which from the external channel 8 is rotated by the external swirler 28 axially.

In order to generate a rotational movement of the flames, several conditions are met. The rate of rotation S must be high in the internal channel 6. This rate of rotation S is greater than 0.6. Indeed, below 0.6, there is no formation of a recirculation zone with a sufficient depression in the center because the tangential velocity of the hydrogen flow is not sufficient.

[0064] The outer swirl 28 also participates in the maintenance of the recirculation zone. We note Sext the dimensionless number associated with the rate of rotation generated by the external spin 28. Sext is greater than 0.6. S _ex t is defined analogously to S, that is to say it is a ratio of a tangential velocity to an axial flow velocity of the air flow.

[0065] A stabilization of the flame, unhooked or hooked to the downstream end 16 of the internal channel 6, depends on a stretching of a shear layer upstream of the downstream end of the internal channel on which the flame can 'hang. To aerodynamically stabilize a flame away from the downstream end of the internal channel, it is necessary to stretch a base of the flame sufficiently in order to extinguish it locally and make it stabilize away from the downstream end of the channel. internal. The main parameters controlling a local stretching value are the rate of rotation of the dihydrogen flow characterized by the dimensionless number S, the distance r and a discharge velocity Ui of the dihydrogen in the internal channel.

For a spin characterized by a rate of rotation S greater than 0.6, a flow velocity Ui of the dihydrogen in the internal channel must be greater than a critical value Ui, _c satisfying the following relationship:

Or :

- P is a pressure in the annular combustion chamber;

- S is the rate of rotation generated by the internal spin 14 of the internal channel 6;

- T _a is an air temperature in Kelvin in the external channel;

- p between 1 and 1.5 is a factor depending on the type of auger used;

- So=O.6, P _o =1 bar, T _a o=3OO K and Ui, _c o=18 m/s

This relationship is based on three observations. The first observation is that a stretching of the flame causing the extinction of this flame increases as the pressure P and as the temperature T ⁰⁸ . The second observation makes it possible to specify that the stretching of the flame increases when the rate of rotation in the internal channel increases. More precisely, the more the flow is blocked at the downstream end of the internal channel, the more the radial velocities are important, the more the flames are stretched at the level of the lips. The third observation specifies that for a given rate of rotation S, the blocking rate will also depend on the spin technology used, hence the power /? in the formula. The value range of /? which is between 1 and 1.5 is a good framework.

Depending on the desired richness and to limit the speeds in the annular channel and therefore the pressure drops, this amounts to choosing D/d between 3 and 10.

There is an optimum value for the distance r which depends on the internal diameter D of the external annular channel. If the distance r is too high, the recirculation zone 20 becomes unstable. Under such conditions, the distance r must be between 0.05D and 0.5D.

[0068] Depending on the distance r, the mixture will take place more or less early inside the dihydrogen 2 and air injection device and if this occurs too early, the flame 22 can rise to the interior of the external annular channel 8 between the downstream end 16 of the internal channel and the downstream end 24 of the external annular channel, which is very damaging to the device and to the bottom of the combustion chamber 4. The rotation of the flame 22 is therefore configured to prevent the flame 22 from rising in the dihydrogen injection device 2. The parameters to be controlled are both the rate of rotation S of the flow in the internal channel, the rate of rotation Sext, and the distance r.

In the context of this document, the spins 14.28 allow to rotate a first flow relative to a second flow. The integration of the internal swirl 14 to the internal channel 6 makes it possible to create the recirculation zone 20 of a flow of dihydrogen passing through said internal channel 6 and preventing the flame from coming to stabilize on the downstream end of the internal channel. The internal twist 14 of the internal channel 6 rotates the flow of dihydrogen 2 sufficiently to create a recirculation zone penetrating inside the internal channel 6 which blocks part of the flow of dihydrogen along the axis longitudinal x of said internal channel 6 generating significant overspeeds relative to the axial flow rate near the walls of the internal channel 6. The rotation of the dihydrogen of the internal channel 6 makes it possible to avoid hanging the flame 22 on the downstream ends of the external annular channel 8 by stabilizing it aerodynamically above the internal channel 6. This rotation of the dihydrogen of the internal channel 6 avoids the installation of a complex cooling device for the dihydrogen injection device 2.

[0070] This stabilization of the flame 22 at a distance facilitates the partial mixing of the air with the dihydrogen inside the outer channel 8 above the downstream end 16 of the inner channel, upstream of the flame 22, and avoiding any risk of flashback 22, also called "flash back" in English, in said internal channel 6 and in the annular channel external 8 upstream of the downstream end 16 of the internal channel 6. This makes it possible to achieve a combustion depleted in dihydrogen in the combustion chamber. This device thus tends to greatly reduce the combustion temperatures and the nitrogen oxides emitted. This also guarantees the integrity of a combustion chamber.

The positioning of the downstream end 16 of the internal channel 6 upstream of the downstream end 24 of the external annular channel 8 makes it possible to optimize the mixture between the dihydrogen and the air. This increases the operating range where the flame 22 is detached by moving back the dihydrogen introduction zone with respect to the aerodynamic stabilization zone of the flame.

The optimization made of this injector and of its architecture is specifically oriented towards the combustion of dihydrogen. The dihydrogen burning much faster than any other fuel and in particular kerosene, the speeds of rotation between the injection device 2 bringing the fuel and that bringing the air are not in the same orders of magnitude as those used for kerosene. Since kerosene is liquid, passage sections of such kerosene injection devices are very small. At the exit of a kerosene injection device, an exit channel is of the order of a millimeter or less than a millimeter. Where in this document, the order of magnitude is several millimeters. Operation is therefore very different for a gaseous fuel such as dihydrogen.

[0073] The injection device is advantageously implemented within an assembly comprising said injection device, in which the internal channel is fluidically connected to means for supplying dihydrogen and the external annular channel is fluidically connected. to air supply means.

The dihydrogen supply means are in particular suitable for delivering a gaseous dihydrogen stream without diluent gas, that is to say a stream comprising at least 90% of dihydrogen by mass, and in particular at least 95% of dihydrogen by mass, and advantageously at least 99% dihydrogen by mass. The dihydrogen supply means comprise for example at least one pressurized tank equipped with at least one valve, and/or at least one chemical generation device for gaseous dihydrogen.

[0075] The air supply means are in particular suitable for delivering a flow of air without adding diluent gas. The air supply means comprise for example an atmospheric air inlet upstream of the turbine engine. This air is compressed before entering the annular combustion chamber. The air supply means may also include a source of oxygen for airflow enrichment in oxygen. The oxygen source can comprise a pressurized oxygen tank provided with a valve and/or means for the chemical generation of gaseous oxygen.

Claims

[Claim 1] Dihydrogen injection device (2) of longitudinal axis (X) intended to be mounted on an annular bottom of an annular combustion chamber (4) of a turbomachine (1) comprising an internal channel ( 6) circulation of dihydrogen and an outer annular channel (8) for the circulation of a mixture comprising at least air, the inner channel (6) and the outer annular channel (8) being coaxial, an internal spinner (14 ) being housed in the internal channel (6) and an external auger (28) being housed in the external annular channel (8), and in which a downstream end (16) of the internal channel (6) is arranged upstream, at a distance r from a downstream end (24) of the outer annular channel (8).

[Claim 2] Device according to claim 1, in which the internal channel (6) is a central tubular channel.

[Claim 3] Device according to one of the preceding claims, in which at least the internal spiral (14) of the internal channel (6) has a helical shape.

[Claim 4] Device according to one of the preceding claims, in which the internal auger (14) is arranged along the longitudinal axis downstream of the external auger (28).

[Claim 5] Device according to one of the preceding claims, in which a rate of rotation S generated by the internal swirl (14) of the internal channel (6), defined as a ratio between a tangential speed and a delivery speed according to the longitudinal axis of a flow of dihydrogen at the outlet of the internal swirler (14), is equal to or greater than 0.6.

[Claim 6] Device according to one of the preceding claims, in which the internal spiral (14) of the internal channel (6) is arranged upstream, at a distance l, from the downstream end (16) of the internal channel (6 ).

[Claim 7] Device according to one of the preceding claims, in which a thickness e of a wall of the internal channel (6) and an internal diameter d of the internal channel (6) are such that a ratio e/d is comprised between 0.05 and 0.7.

[Claim 8] Device according to one of the preceding claims, in which the internal channel (6) has an internal diameter d and the external annular channel (8) has an internal diameter D such that a ratio D/d is between 3 and 10.

[Claim 9] Device according to claims 6 and 7, in which an l/d ratio is between 1 and 3.

[Claim 10] Device according to claim 8, in which the distance r is between 0.05D and 0.5D.

[Claim 11] Device according to one of the preceding claims, in which the external spiral (28) of the external annular channel (8) is arranged at the level of an upstream end (30) of the said external annular channel (8), at a distance L from the downstream end (24) of the outer annular channel (8).

[Claim 12] Device according to claims 8 and 11, in which the distance L is between 1D and 5D.

[Claim 13] Device according to one of the preceding claims, in which the rate of rotation S is greater than 0.6, a flow rate Ui of the dihydrogen in the internal channel being greater than a critical value Ui, _c which verifies the relationship next :

Or :

- P is a pressure in the annular combustion chamber;

- S is a rate of rotation generated by the internal spin (14) of the internal channel (6);

- T _a is an air temperature in Kelvin in the external channel;

- p between 1 and 1.5 is a factor depending on the type of auger used;

- So=O.6, P _o =1 bar, T _a o=3OO K and Ui, _c o=18 m/s.

[Claim 14] Device according to one of the preceding claims, in which the mixture is air.

[Claim 15] Assembly comprising the device according to one of the preceding claims, in which the internal channel (6), fluidly connected to means for supplying dihydrogen, comprises the internal swirl (14) configured to rotate said dihydrogen , and the outer annular channel (8), fluidly connected to air supply means, comprises the outer swirler (28) configured to rotate said air.