Injector for de-icing device for an air intake of an aircraft turbojet nacelle, and associated method

Abstract

The invention relates to an injector (3) for a de-icing device for an air intake of an aircraft turbojet nacelle, the injector (3) comprising a peripheral member (30) internally defining a passage duct (6), the peripheral member (30) comprising a peripheral mouth (31) configured to inject a peripheral hot air flow (FAC) so as to circulate a flow of fresh air in the passage duct (6) from upstream to downstream, the peripheral member (30) comprising an inner guide wall (301) located downstream of the peripheral mouth (30), the peripheral member (30) comprising a plurality of members (4) for rotating the hot air flow (FAC) during the injection thereof.

Description

Injector for a device for de-icing an air inlet of an aircraft turbojet nacelle and associated method

[0001] The present invention relates to the field of aircraft turbojet engines and more particularly relates to an injector for a device for de-icing an air inlet of a nacelle of an aircraft turbojet engine.

[0002] As is known, an aircraft has one or more turbojet engines to enable its propulsion by accelerating a flow of air which circulates from front to back in the turbojet engine.

[0003] With reference to the, there is shown a turbojet engine 100 extending along a turbojet engine axis X and comprising a fan 101 rotatably mounted around the turbojet engine axis X in a nacelle comprising an outer shroud 102. Subsequently, the terms front and rear are defined with respect to the circulation of the air flow F. The turbojet engine 100 comprises at its front end an air inlet 200 comprising a cavity 204, extending annularly around the turbojet engine axis X, which comprises an inner wall 201 facing the turbojet engine axis X and an outer wall 202 which is opposite the inner wall 201, the walls 201, 202 are connected by a leading edge 203 also called "lip of the air inlet". Thus, the air inlet 200 makes it possible to separate the incoming air flow F into an interior air flow FINT guided by the interior wall 201 and an exterior air flow FEXT guided by the exterior wall 202.Subsequently, the terms inner and outer are defined radially relative to the turbojet axis X.

[0004] As is known, during the flight of an aircraft, due to the temperature and pressure conditions, frost is likely to accumulate near the leading edge 203 and the inner wall 201 of the air intake 200 and to form blocks of frost which are likely to be ingested by the turbojet engine 100. Such ingestions must be avoided in order to improve the service life of the turbojet engine 100 and reduce malfunctions.

[0005] To eliminate the accumulation of frost, still with reference to the, it is known to circulate a flow of hot air FAC in the interior cavity 204 in order to heat the interior wall 201 by thermal convection and thus prevent the accumulation of frost which melts as it accumulates.

[0006] The introduction of the hot air flow FAC into the interior cavity 204 is carried out by an injector 300 which is traditionally in the form of a tube of cylindrical section which is oriented in a direction perpendicular to the turbojet axis X as illustrated in the. The hot air flow FAC moves circumferentially in the interior cavity 204 in order to heat the interior wall 201.

[0007] In practice, the energy efficiency of such heating is low since the hot air flow FAC does not mix homogeneously with the cool air flow already present in the interior cavity 204. This can cause hot spots in the air inlet 200 which can reduce its lifespan.

[0008] It has been proposed to use an injector comprising a peripheral member internally defining a passage vein. The peripheral member comprises a peripheral mouth configured to inject a peripheral hot air flow so as to circulate a fresh air flow in the passage vein. The performance of such an injector is high when the section of the passage vein is large in order to allow optimal mixing between the fresh air flow and the hot air flow.

[0009] Installing an injector with a large peripheral component is complex because the injector must be removable through a mounting opening for maintenance purposes. Therefore, the peripheral component must be small to allow removal through the mounting opening, the dimensions of which are determined. PRESENTATION OF THE INVENTION

[0010] The invention relates to an injector for a device for de-icing an air intake of an aircraft turbojet nacelle, the injector comprising a peripheral member internally defining a passage vein, the peripheral member comprising a peripheral mouth configured to inject a peripheral hot air flow so as to circulate a cool air flow in the passage vein from upstream to downstream, the peripheral member comprising an internal guide wall located downstream of the peripheral mouth, the peripheral member comprising a plurality of members for rotating the hot air flow during its injection.

[0011] The peripheral member is circumferential and includes a circumferential mouthpiece configured to inject a circumferential flow of hot air. The mouthpiece describes a closed contour.

[0012] Thanks to the invention, the flow of fresh air and the flow of hot air circulate concentrically, which allows an acceleration of the flow of fresh air by the flow of hot air while promoting their mixing. The inner guide wall makes it possible to promote the creation of a depression zone upstream of the passage vein in order to accelerate the flow of fresh air from upstream to downstream while guiding the flow of hot air pressed against the inner guide wall.

[0013] The use of rotating members also promotes mixing by forming turbulence at the interface between the hot air flow and the cool air flow. Such an injector remains advantageously efficient even for a peripheral member having a small diameter, preferably less than half the distance defined between the partition and the leading edge of the air inlet, i.e., its front end. Preferably, the diameter of the peripheral member is less than 150 mm.

[0014] Advantageously, the interior cavity of the air inlet is heated with a mixed air flow of optimal temperature, limiting the appearance of hot spots, with a high flow rate so as to allow optimal transfer of calories with the walls. Defrosting performance is improved while reducing the footprint.

[0015] According to a preferred aspect, the injector comprises a supply member, connected to the peripheral member, comprising a mounting foot configured to be fixed to the air inlet in order to be supplied by the flow of hot air. Such an injector is adapted to be mounted by its mounting foot to a through opening of a partition of a traditional air inlet.

[0016] Preferably, the feed member extending along a mounting axis, the mounting foot comprising a passage section, the peripheral member has a space section, defined in projection in a plane orthogonal to the mounting axis, which is smaller than that of the passage section of the mounting foot. Advantageously, if the mounting foot can be moved via a through opening of a partition of a traditional air inlet, the peripheral member can also be moved in a similar manner. In other words, this allows the injector to be removed via the through opening in the event of maintenance, which is advantageous. Thanks to the rotation members, a peripheral member of reduced dimensions can be used to achieve optimal mixing while being able to accommodate a traditional maintenance step.

[0017] Preferably, the peripheral member comprises an inner guide wall, the inner guide wall being located downstream of the peripheral mouth.

[0018] According to one aspect, the peripheral member comprising an inner guide wall, a plurality of rotation members is positioned on the inner guide wall. The use of rotation members on the inner guide wall makes it possible to twist the flow of hot air following its injection while taking advantage of the fact that the flow of hot air is pressed against the inner guide wall. The positioning of the rotation members on the inner guide wall makes it possible to use large rotation members and thus achieve significant rotation. Advantageously, the use of rotation members on the inner guide wall makes it possible to twist the flow of fresh air circulating in the passage vein, which also improves mixing.

[0019] Preferably, the rotation members have a length at least equal to 90% of the length of the inner guide wall, which improves rotation. Preferably, the section of a rotation member, defined transversely to the injection axis, increases from downstream to upstream so as to allow progressive rotation of the hot air flow while having a moderate impact on the fresh air flow.

[0020] According to another aspect, a plurality of rotation members are positioned in the peripheral mouth. The rotation members are thus integrated into the mouth, which allows optimal pressing on the inner guide wall. Preferably, the rotation members have a length of between 2 and 20 times the thickness of the peripheral mouth 31. Preferably, the rotation members have a length of less than 20 mm.

[0021] Preferably, the peripheral member comprising an inner guide wall, the inner guide wall is smooth.

[0022] Preferably, the peripheral member is configured to accelerate the flow of fresh air by Coanda effect in the passage vein. The hot air flow follows the outer surface of the peripheral body to generate a depression upstream of the passage vein in order to accelerate the flow of fresh air from upstream to downstream. Thus, without a rotating member, the air flow in the cavity is accelerated. This makes it possible to improve the mixing of the hot air flows and the fresh air flows and to promote the circulation of the air flows in the circumferential direction of the cavity.

[0023] Preferably, the peripheral member has a peripheral mouth facing downstream. Such a peripheral mouth advantageously allows the flow of hot air to follow the outer surface of the peripheral body to accelerate the flow of fresh air. The plating is optimal.

[0024] Preferably, the inner guide wall comprises a downstream end extending parallel to the injection axis so as to straighten the flow of hot air. Thus, the flow of hot air makes it possible to guide the flow of fresh air and to mix with the latter according to the injection direction.

[0025] Preferably, the inner guide wall is flared radially downstream.

[0026] Preferably, the inner guide wall makes it possible to promote the creation of a depression zone upstream of the passage vein in order to accelerate the flow of fresh air from upstream to downstream while guiding the flow of hot air pressed against the inner guide wall.

[0027] Preferably, the peripheral member comprising a heating cavity supplied with a hot air flow, the heating cavity comprising an injection channel located directly near the peripheral mouth, the injection channel is convergent so as to accelerate the hot air flow towards the peripheral mouth. The convergent channel makes it possible to minimize the pressure losses of the hot air flow. The high speed of the hot air flow at the injection outlet makes it possible to increase the flow rate of the fresh air flow by entrainment effect.

[0028] Preferably, the peripheral member comprises a peripheral lip extending projecting into the heating cavity and partially delimiting the injection channel. This allows the injection speed to be conveniently adjusted to obtain the desired plating effect.

[0029] Preferably, the peripheral lip extends in continuity with the inner guide wall. This allows a peripheral member to be formed conveniently without assembly. Preferably, the walls of the peripheral member are made of material.

[0030] According to one aspect of the invention, the inner guide wall is inclined relative to the injection axis by an angle of inclination of between 5° and 45°, preferably between 10° and 15°, more preferably equal to 12°. Such an angle of inclination makes it possible to obtain an optimal Coanda effect to ensure acceleration and efficient mixing.

[0031] According to one aspect, each rotation member comprises an upstream portion and a downstream portion which are offset in the circumferential direction so as to rotate the flow of hot air.

[0032] The invention also relates to a de-icing device for an air inlet of an aircraft turbojet engine nacelle extending along a turbojet engine axis, the air inlet comprising an inner cavity extending annularly around the turbojet engine axis and which comprises an inner wall facing the turbojet engine axis and an outer wall which is opposite the inner wall, the walls being connected by a leading edge, the de-icing device comprising at least one injector as presented previously of a flow of hot air into the inner cavity along an injection axis oriented from upstream to downstream.

[0033] The invention also relates to an air inlet of an aircraft turbojet nacelle extending along an axis, the air inlet comprising an interior cavity, extending annularly around the axis, which comprises an interior wall facing the axis and an exterior wall which is opposite the interior wall, the walls being connected by a leading edge, the air inlet comprising a de-icing device as presented previously.

[0034] The invention also relates to a method of using a de-icing device as presented previously for de-icing an air inlet of an aircraft turbojet nacelle extending along an axis, the air inlet comprising an interior cavity, extending annularly around the axis, which comprises an interior wall facing the axis and an exterior wall which is opposite the interior wall, the walls being connected by a leading edge.

[0035] The method comprises a step of injecting a peripheral and twisted hot air flow so as to circulate a fresh air flow in the passage vein, the fresh air flow circulating from upstream to downstream relative to an injection axis, the fresh air flow circulating internally to the peripheral hot air flow in order to allow mixing between the hot air flow and the fresh air flow. PRESENTATION OF FIGURES

[0036] The invention will be better understood on reading the following description, given solely by way of example, and referring to the appended drawings given as non-limiting examples, in which identical references are given to similar objects and in which:

[0037] This is a schematic representation of an air intake of a nacelle according to the prior art.

[0038] This is a schematic cross-sectional representation of the circulation of a hot air flow in the air inlet according to the prior art.

[0039] This is a schematic representation of an air inlet of a nacelle according to the invention.

[0040] This is a schematic representation from downstream of an injector according to one embodiment of the invention.

[0041] This is a schematic side sectional representation of the injector.

[0042] This is a schematic representation in angular section of the peripheral organ of the injector.

[0043] This is a schematic representation of an injector according to a first embodiment.

[0044] This is a sectional representation of an injector according to the first embodiment.

[0045] This is another schematic representation of an injector according to the first embodiment.

[0046] This is a partial schematic representation of an injector according to a second embodiment.

[0047] This is a close-up sectional representation of an injector according to the second embodiment.

[0048] This is a schematic representation in side section of the peripheral member of the injector with the circulation of the hot air flow in the peripheral member and its rotation.

[0049] This is a schematic cross-sectional representation of the circulation of a hot air flow in the air inlet according to the invention.

[0050] It should be noted that the figures set out the invention in detail to implement the invention, said figures can of course be used to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0051] With reference to the, there is shown a turbojet engine 1 extending along a turbojet engine axis X and comprising a fan 10 rotatably mounted around the turbojet engine axis X in a nacelle comprising an outer shroud 12. Subsequently, the terms front and rear are defined with respect to the circulation of the air flow F. The turbojet engine 1 comprises at its front end an air inlet 2 which comprises an interior cavity 20, extending annularly around the turbojet engine axis X, which comprises an interior wall 21 facing the turbojet engine axis X and an exterior wall 22 which is opposite the interior wall 21. The walls 21, 22 are connected by a leading edge 23 also called "air inlet lip". Thus, the air inlet 2 makes it possible to separate the incoming air flow F into an interior air flow FINT guided by the interior wall 21 and an exterior air flow FEXT guided by the exterior wall 22.Subsequently, the terms inner and outer are defined radially relative to the turbojet axis X. The inner cavity 20 is delimited in front by the inner wall 21 and the outer wall 22 connected by the leading edge 23. In this example, the inner cavity 20 is delimited in the rear by a separating partition 24.

[0052] The inner cavity 20 is filled with a fresh air flow FAF, for example, a stagnant air flow or a hot air flow that was previously injected and has cooled.

[0053] The turbojet engine 1 comprises a de-icing device for eliminating the accumulation of frost on the air inlet 2. In a known manner, the de-icing device comprises an injector 3 of a hot air flow FAC into the interior cavity 20. The circulation of a hot air flow FAC makes it possible, by thermal convection, to prevent the accumulation of frost which melts as it accumulates. Preferably, the hot air flow FAC is taken from the turbojet engine 1.

[0054] As illustrated in the, the injector 3 comprises a peripheral member 30 internally defining a passage vein 6. The passage vein 6 is a through vein. In this example, the peripheral member 30 has a circular shape but it goes without saying that it could have another peripheral shape, for example, an elongated shape, in particular, oblong. With reference to the, the passage vein 6 has a disc-shaped section but it goes without saying that other shapes could be suitable.

[0055] As illustrated in the, the peripheral member 30 is oriented along an injection axis X3 along which the passage vein 6 extends. The injection axis X3 is oriented from upstream to downstream on the. In this example, with reference to the, the injection axis X3 extends substantially tangentially / perpendicularly relative to the turbojet axis X.

[0056] As illustrated in Figures 4 and 6, the peripheral member 30 comprises a peripheral mouth 31 configured to inject a hot air flow FAC from upstream to downstream along the injection axis X3. The peripheral mouth 31 has a shape similar to the peripheral member 30. In this example, the peripheral mouth 31 is circular in shape and is oriented downstream.

[0057] With reference to the, the peripheral member 30 comprises a heating cavity 33 and a supply member 32 configured to supply the heating cavity 33 with hot air flow FAC. The supply member 32 is preferably in the form of a hollow casing. In this example, the supply member 32 comprises a mounting foot 39 configured to be fixed to the air inlet 2, in particular, to the partition wall 24. As illustrated in the, the supply member 32 extends along a mounting axis XM which is preferably substantially parallel to the turbojet axis X (see) but it goes without saying that this could be different. The heating cavity 33 defines a radially inner wall and a radially outer wall. The passage vein 66 extends internally to the radially inner wall.

[0058] As illustrated in , the mounting foot 39 defines a passage section S1 relative to said mounting axis XM. In this example, the mounting foot 39 has a disc shape and the passage section corresponds to the surface of said disc. It goes without saying that the shape of the mounting foot 39 could be different. In practice, the mounting foot 39 is mounted in a through opening OM formed in the partition wall 24 whose section is substantially similar to that of the mounting foot 39. During a maintenance operation, the injector 3 is moved along the mounting axis XM through the through opening OM.

[0059] The peripheral member 30 has, in projection in a plane orthogonal to the mounting axis XM, a cross-section S2 which is smaller than that of the passage cross-section S1 in order to allow the injector 3 to be removed via the opening OM. This dimensional constraint requires the injector 3 to allow optimal mixing of the hot air flow FAC with the fresh air flow FAF.

[0060] With reference to the, the peripheral mouth 31 is configured to inject, from the heating cavity 33, a hot air flow FAC of peripheral shape so as to circulate a fresh air flow FAF in the passage vein 6. The fresh air flow FAF circulates from upstream to downstream relative to the injection axis X3, the fresh air flow FAF circulating internally to the hot air flow FAC of peripheral shape in order to allow mixing between the hot air flow FAC and the fresh air flow FAF. As will be presented subsequently, the hot air flow FAC has a swirling movement when it is injected while having a peripheral shape.

[0061] As illustrated in the, the hot air flow FAC has a peripheral shape, here an annular section, and the fresh air flow FAF is guided axially along the injection axis X3 inside the hot air flow FAC. In other words, the hot air flow FAC and the fresh air flow FAF are concentric. As will be presented later, the peripheral member 30 is configured to accelerate the fresh air flow FAF by Coanda effect in the passage vein 6 as illustrated in the.

[0062] With reference to the, the hot air flow FAC is guided by the surface of the peripheral member 30 so as to allow high-speed injection. This makes it possible to generate, downstream of the peripheral mouth 31, a depression zone which makes it possible to suck in the fresh air flow FAF located upstream of the peripheral mouth 31. In other words, due to the injection of the hot air flow FAC, the fresh air flow FAF is driven downstream along the injection axis X3, which increases its speed in the manner of a bladeless fan.

[0063] Advantageously, with reference to the, the depression generated downstream also makes it possible to suck in fresh air flows FAF having bypassed the passage vein 6, which generates turbulence T downstream of the peripheral member 30. Such turbulence T is advantageous given that it makes it possible to promote mixing between the hot air flow FAC and the fresh air flow FAF, thus avoiding the appearance of hot spots in the interior cavity 20.

[0064] With reference to the, the peripheral member 30 is generally shown seen in longitudinal section along the injection axis X3. The peripheral member 30 comprises a section comprising an inner guide wall 301, an outer wall 302, an upstream wall 303 and a downstream wall 304. These walls internally delimit the heating cavity 33. Preferably, the walls 301-304 of the peripheral member 30 are made of material.

[0065] With reference to the, the upstream wall 303 is preferably convex and streamlined so as to allow turbulence-free circulation of the fresh air flow FAF. The upstream wall 303 makes it possible to guide fresh air flows FAF into the passage vein 6 so that they are accelerated and fresh air flows FAF externally to the peripheral member 30 to generate turbulence T downstream. The outer wall 302 is here cylindrical so as to axially guide the fresh air flow FAF which bypasses the passage vein 6.

[0066] In this example, the inner guide wall 301 is divergent from upstream to downstream, that is to say, flared radially from upstream to downstream. In other words, the passage vein 6 has an increasing section. The inner guide wall 301 is located downstream of the peripheral mouth 31 so as to guide the hot air flow FAC leaving the peripheral mouth 31 in order to obtain the Coanda effect. As will be presented later, the hot air flow FAC circulates in contact with the inner guide wall 301, which makes it possible to suck in the cool air flow FAF to accelerate it. With reference to the, the inner guide wall 301 is inclined relative to the injection axis X3 by an angle of inclination θ of between 5° and 45° in order to obtain an optimal Coanda effect. Preferably, the angle of inclination θ is between 10° and 15°, preferably equal to 12°.Advantageously, the peripheral mouth 31 is oriented so as to allow injection along the inner guide wall 301. The hot air flow FAC is thus pressed against the inner guide wall 31.

[0067] In this example, the inner guide wall 301 comprises a downstream end 301a extending along the injection axis X3. The downstream end 301a makes it possible to straighten the hot air flow FAC to enable the cool air flow FAF to be guided along the injection axis X3.

[0068] With reference to 1a, the downstream wall 304 is configured to amplify the turbulence T and has, in this example, a non-streamlined truncated shape. In order to allow very high-speed injection via the peripheral mouth 31, the heating cavity 33 comprises an injection channel 34 located directly near the peripheral mouth 31. Preferably, the injection channel 34 is convergent so as to accelerate the hot air flow FAC during its injection via the peripheral mouth 31. Preferably, as illustrated in 1a, the peripheral member 30 comprises a peripheral lip 35 extending projecting into the heating cavity 33 and partially delimiting the injection channel 34. Such a peripheral lip 35 makes it possible to precisely define the shape of the injection channel 34 and, consequently, the desired compression.Preferably, the peripheral lip 35 extends in the continuity of the inner guide wall 301 so as to define the peripheral mouth 31 between the inner guide wall 301 and the upstream wall 303 of the peripheral member 30.

[0069] According to the invention, the peripheral member 30 comprises a plurality of members for rotating the hot air flow FAC during its injection into the interior cavity 20 of the air inlet 2. As will be presented in detail later, such rotating members make it possible to generate a swirl on the hot air flow FAC while keeping it pressed against the interior guide wall 301 to allow optimal suction of the fresh air flow FAF. Such a swirl makes it possible to improve the mixing of the hot air flow FAC with the fresh air flow FAF while retaining an injector 3 of reduced dimensions.

[0070] Preferably, the angle of inclination of the rotation members relative to the injection axis is between 20° and 40° to obtain the desired twisting effect. Preferably, as illustrated in , each rotation member 4 comprises an upstream portion 4A and a downstream portion 4B which are offset in the circumferential direction so as to rotate the hot air flow FAC. Preferably, the ratio between the length of a rotation member and the distance between two rotation members is between 1 and 1.4 to ensure a compromise between the number of rotation members and the deflection capacity.

[0071] According to a first embodiment, with reference to figures 7 to 9, a plurality of rotation members 4 is positioned on the inner guide wall 301. Each rotation member 4 projects towards the injection axis X3 in order to form a relief on the inner guide wall 301. Preferably, a rotation member 4 is in the form of a bump formed between two hollows.

[0072] Preferably, the number, shape and length of the rotation members 4 are adapted to obtain the desired twisting effect. Preferably, the rotation members 4 have a length at least equal to 90% of the length of the inner guide wall 301. Preferably, the section of a rotation member 4, defined transversely to the injection axis X3, increases from downstream to upstream so as to allow progressive rotation of the hot air flow FAC but also of the cool air flow FAF via the rotation members 4.

[0073] Preferably, the rotation members 4 are distributed uniformly around the periphery of the inner guide wall 301 in order to obtain a homogeneous twisting effect. In this example, the rotation members 4 are made from the material of the inner guide wall 301.

[0074] Thus, when injecting a hot air flow FAC via the mouth 31, the hot air flow FAC is pressed against the inner guide wall 301 which causes it to rotate at high speed. This makes it possible, on the one hand, to create a suction of the fresh air flow FAF and, on the other hand, to generate turbulence due to the rotation which improves the mixing between the hot air flow FAC and the fresh air flow FAF.

[0075] According to a second embodiment, with reference to Figures 10 to 11, a plurality of rotation members 5 is positioned in the peripheral mouth 31. Preferably, the number, shape and length of the rotation members 5 is adapted to obtain the desired twisting effect. Preferably, the length of the rotation members 5 is between 2 and 20 times the thickness of the peripheral mouth 31 in order to allow rotation while maintaining a reduced size in the peripheral mouth 31. Preferably, the rotation members 5 have a length of less than 20 mm.

[0076] Preferably, the rotation members 5 are distributed uniformly around the periphery of the mouth 31 in order to obtain a homogeneous twisting effect. In this example, the rotation members 5 are made from the material of the peripheral member 30. Preferably, the inner guide wall 301 remains smooth in order not to disturb the suction of the fresh air flow FAF. Preferably, each rotation member 5 is in the form of a fin.

[0077] Thus, when injecting a hot air flow FAC via the mouth 31, the hot air flow FAC is twisted and then pressed against the inner guide wall 301. This makes it possible, on the one hand, to create a suction of the fresh air flow FAF and, on the other hand, to generate turbulence due to the rotation which improves the mixing between the hot air flow FAC and the fresh air flow FAF. In this embodiment, the fresh air flow FAF is not rotated by the rotation members 5.

[0078] It goes without saying that the embodiments are compatible and that an injector 3 could comprise rotation members in the peripheral mouth 31 and on the inner guide wall 301.

[0079] In the two embodiments presented previously, the peripheral member 30 has, in projection in a plane orthogonal to the mounting axis XM, a cross-section S2 which is smaller than that of the passage section S1 of the mounting foot 39 as illustrated in. Maintenance can be carried out in a practical manner. Preferably, the passage section S1, defining a maintenance passage, has a diameter of between 40mm and 150mm in order to be able to adapt to an existing defrosting device. Preferably, the peripheral member 30 has a diameter of between 35mm and 140mm. Preferably, a clearance is defined between the diameter of the passage section S1 and the diameter of the cross-section S2 which is between 5mm and 10mm.

[0080] Preferably, the peripheral member 30 has a small diameter, preferably less than half the distance d () defined between the partition 24 and the leading edge of the air inlet 2, that is to say, its front end. Preferably, the diameter of the peripheral member 30 is less than 140 mm.

[0081] An example of implementation of a method for using a defrosting device according to the invention will now be presented. The method comprises a step consisting of injecting a hot air flow FAC of peripheral shape into the interior cavity 20 so as to circulate a fresh air flow FAF in the passage vein 6. The fresh air flow FAF circulates from upstream to downstream relative to the injection axis X3 internally to the hot air flow FAC of peripheral and twisted shape as illustrated in Figures 12 and 13.

[0082] During its injection, the hot air flow FAC is set in rotation by the rotation members 4, 5 of the peripheral member 30, which increases the turbulence and improves the mixing with the fresh air flow FAF while maintaining limited bulk.

[0083] The hot air flow FAC is injected at very high speed due to its optimal compression by the injection channel 34 into the heating cavity 33. During its injection, the hot air flow FAC hugs the inner guide wall 301 which generates a depression in the passage vein 6 sucking in the fresh air flow FAF located upstream. As a result, the fresh air flow FAF is accelerated during the injection of the hot air flow FAC, which increases the air flow in the inner cavity 20 of the air inlet 2. Heat exchanges with the walls 21, 22, 23 of the air inlet 2 are favored, which prevents any accumulation of frost.

[0084] As illustrated in, when the fresh air flow FAF circulates internally to the hot air flow FAC of peripheral and twisted shape, the latter mix at the outlet of the injector 3 in order to form a mixed air flow FAM of optimal temperature. In other words, the risk of forming a hot spot in the air inlet 2 is reduced. The service life of the air inlet 2 is increased. Such an injector 3 can be mounted in an existing air inlet 2 by a through opening OM formed in the internal partition 24 of the air inlet 2.

[0085] Furthermore, due to the characteristics of the peripheral member 30, turbulence T appears downstream of the peripheral member 30 which makes it possible to homogenize the mixture between the fresh air flow FAF and the hot air flow FAC. The mixed air flow FAM thus allows homogeneous heating of the walls 21, 22, 23 of the air inlet 2.

[0086] Thanks to the invention, a mixed air flow FAM of optimal temperature and high flow rate circulates in the interior cavity 20 to defrost the walls 21, 22, 23 of the air inlet 2.

Claims

Injector (3) for a device for de-icing an air inlet (2) of a nacelle of an aircraft turbojet engine (1), the injector (3) comprising a peripheral member (30) internally defining a passage vein (6), the peripheral member (30) comprising a peripheral mouth (31) configured to inject a peripheral hot air flow (FAC) so as to circulate a fresh air flow (FAF) in the passage vein (6) from upstream to downstream, the peripheral member (30) comprising an inner guide wall (301) located downstream of the peripheral mouth (30), the peripheral member (30) comprising a plurality of members (4, 5) for rotating the hot air flow (FAC) during its injection. Injector (3) according to claim 1, wherein the injector (3) comprises a supply member (32), connected to the peripheral member (30), comprising a mounting foot (39) configured to be fixed to the air inlet (2) in order to be supplied by the hot air flow (FAC). Injector (3) according to claim 2, in which, the supply member (32) extending along a mounting axis (XM), the mounting foot (39) comprising a passage section (S1), the peripheral member (30) has a bulk section (S2), defined in projection in a plane orthogonal to the mounting axis (XM), which is smaller than that of the passage section (S1) of the mounting foot (39). Injector (3) according to one of claims 1 to 3, in which, the peripheral member (30) comprising an inner guide wall (301), the inner guide wall (301) is located downstream of the peripheral mouth (31). Injector (3) according to claim 4, in which, the inner guide wall (301) is flared radially downstream, a plurality of rotation members (4) is positioned on the inner guide wall (301). Injector (3) according to claim 4, wherein the inner guide wall (301) is smooth. Injector (3) according to one of claims 1 to 6, in which a plurality of rotation members (5) is positioned in the peripheral mouth (31). Injector (3) according to one of claims 1 to 7, in which each rotation member (4) comprises an upstream portion (4A) and a downstream portion (4B) which are offset in the circumferential direction so as to rotate the hot air flow (FAC). De-icing device for an air inlet (2) of a turbojet engine nacelle (1) of an aircraft extending along a turbojet engine axis (X), the air inlet (2) comprising an inner cavity (20) extending annularly around the turbojet engine axis (X) and which comprises an inner wall (21) facing the turbojet engine axis (X) and an outer wall (22) which is opposite the inner wall (21), the walls (21, 22) being connected by a leading edge (23), the de-icing device comprising at least one injector (3) according to one of claims 1 to 8 of a hot air flow (FAC) into the inner cavity (20) along an injection axis (X3) oriented from upstream to downstream. Air inlet (2) of a nacelle of an aircraft turbojet engine (1) extending along a turbojet engine axis (X), the air inlet (2) comprising an inner cavity (20), extending annularly around the turbojet engine axis (X), which comprises an inner wall (21) facing the turbojet engine axis (X) and an outer wall (22) which is opposite the inner wall (21), the walls (21, 22) being connected by a leading edge (23), the air inlet (2) comprising a de-icing device according to claim 9. A method of using a de-icing device according to claim 9 for de-icing an air inlet (2) of a turbojet engine nacelle (1) of an aircraft extending along a turbojet engine axis (X), the air inlet (2) comprising an inner cavity (20), extending annularly around the turbojet engine axis (X) and which comprises an inner wall (21) facing the turbojet engine axis (X) and an outer wall (22) which is opposite the inner wall (21), the walls (21, 22) being connected by a leading edge (23), the method comprising a step of injecting a peripheral and twisted hot air flow (FAC) so as to circulate a fresh air flow (FAF) in the passage vein (6), the fresh air flow (FAF) circulating from upstream to downstream relative to an axis injection (X3),the fresh air flow (FAF) circulating internally to the hot air flow (FAC) of peripheral shape in order to allow mixing between the hot air flow (FAC) and the fresh air flow (FAF).,

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