Air intake duct lip of an aircraft engine nacelle comprising at least one infrared radiation source

Abstract

The invention discloses a lip (2a) of an air intake duct (2) of an aircraft turbine nacelle (1), wherein the nacelle extends along an axis X, wherein an air flow (F) flows from upstream to downstream, the lip (2a) extending around the axis X and comprising an inner wall (21) facing the axis X and an outer wall (22) opposite the inner wall (21), the inner wall (21) and the outer wall (22) being connected by an upstream wall (23) and a partition wall (25) to define an annular cavity (24) for accommodating at least one infrared radiation source (9), and at least one of the inner wall (21), the outer wall (22) and the upstream wall (23) being made of a material capable of transmitting at least 30% of the infrared radiation received on the inner surface of the wall to the outer surface of the wall.

Description

Technical Field

[0001] The present invention relates to the field of aircraft turbines, and more particularly to a device for deicing an air inlet lip of an aircraft turbine nacelle. Background Art

[0002] As is known, aircraft include one or more turbines in order to achieve aircraft propulsion by accelerating an air flow flowing from upstream to downstream in the turbine.

[0003] refer to Figure 1 , which shows a turbine 100 extending along an axis X. The turbine 100 includes a fan 101 that rotates about the axis X and is mounted in a nacelle including a casing 102, so as to accelerate an airflow F from upstream to downstream. Hereinafter, the terms "upstream" and "downstream" are defined in terms of the flow direction of the airflow F. The turbine 100 includes an inlet duct 200 at its upstream end, which is used to separate the incoming airflow F into an internal airflow FINT accelerated by the fan 101 and an external airflow FEXT directed outside the nacelle. The inlet duct 200 includes an upstream portion, referred to by those skilled in the art as a lip, and a downstream portion.

[0004] The lip includes an inner wall 201 facing the axis X and an outer wall 202 opposite the inner wall 201. The inner wall 201 and the outer wall 202 are connected by an upstream wall 203 and a partition wall 205 to form an annular cavity 204, which is referred to by those skilled in the art as a "D-duct." The lip thus enables the incoming airflow F to be separated into an inner airflow FINT guided by the inner wall 201 and an outer airflow FEXT guided by the outer wall 202. Hereinafter, the terms "inner" and "outer" are defined in the radial direction of the axis X of the turbine 100.

[0005] As is known, during flight of an aircraft, due to temperature and pressure conditions, ice may accumulate on the upstream wall 203 of the lip, the outer wall 202 and the inner wall 201 and form ice blocks that may be sucked into the turbine 100. In order to increase the life of the turbine 100 and reduce failures, such ingestion should be avoided.

[0006] To avoid ice accumulation, refer to Figure 1 Patent application FR2986779A1 discloses equipping a nacelle with a de-icing device 209 that emits infrared radiation to heat opposite portions of the intake duct and melt ice accumulated on the inner wall 201. In practice, the nacelle includes an envelope 219 in which the de-icing device 209 is mounted to emit infrared radiation onto radially opposite portions of the intake duct 200. The envelope 219 is located downstream of the annular cavity 204 of the lip, i.e., in the region of the nacelle where the acoustic treatment panels are installed.

[0007] A disadvantage of this solution is that it cannot remove ice from the entire lip surface. Specifically, it cannot remove ice that has accumulated on outer wall 202. Furthermore, infrared de-icing device 209 consumes significant power, which impacts the energy efficiency of the nacelle and, more generally, the turbine. Furthermore, when the ice layer is very thick, a significant amount of heat energy must be supplied to completely melt it. Finally, the presence of this de-icing device affects noise attenuation performance by increasing the overall size and reducing the surface area available for mounting acoustic treatment panels.

[0008] Furthermore, patent application FR2930234A1 discloses an air lip comprising an annular cavity, wherein an infrared deicing device is installed in the annular cavity to heat the air intake duct lip by heat conduction. Summary of the Invention

[0009] One of the objects of the present patent application is to provide a nacelle air inlet lip comprising a de-icing device in order to at least partially obviate the aforementioned drawbacks.

[0010] The invention relates to an air inlet lip for an aircraft turbine nacelle, the nacelle extending along an axis X, wherein the airflow flows from upstream to downstream, the lip extending around the axis X and comprising an inner wall facing the axis X and an outer wall opposite the inner wall, the inner and outer walls being connected by an upstream wall and a partition wall so as to delimit an annular cavity accommodating at least one infrared radiation source.

[0011] The present invention is notable in that at least one of the inner wall, outer wall, and upstream wall is made of a material configured to transmit at least 30% of infrared radiation received on the inner surface of the wall to the outer surface of the wall. The terms "inner" and "outer" are defined relative to the annular cavity. Thus, each wall of the lip includes an inner surface facing the annular cavity and an outer surface opposite the inner surface.

[0012] Thus, infrared radiation is transmitted through the material. Advantageously, 30% of the infrared radiation received on the inner surface is sufficient to locally melt the interface between the ice layer and the wall to be de-iced, thereby enabling rapid ice removal without requiring complete melting of the ice as in the prior art. Furthermore, the infrared radiation source within the annular cavity ensures that the overall dimensions of the downstream portion of the annular cavity are not increased. Consequently, noise attenuation panels can be installed without difficulty.

[0013] Preferably, at least the inner wall is made of a material capable of transmitting at least 30% of infrared rays received on the inner surface of the wall to the outer surface of the wall.

[0014] Preferably, at least two of the inner wall, the outer wall, and the upstream wall, and more preferably all three walls, are made of a material capable of transmitting at least 30% of infrared radiation received on the inner surface to the outer surface. This advantageously allows for localized heating of the wall of the air intake lip to achieve de-icing.

[0015] According to one aspect, the inner wall includes at least one first portion made of a material configured to transmit at least 60% of infrared light received on the inner surface to the outer surface. Such a transparent wall enables infrared light to be transmitted over long distances, thereby achieving long-range deicing.

[0016] According to one aspect, the inner wall includes at least one second portion, the second portion comprising an inner surface of the inner wall, wherein the inner surface of the inner wall is configured to reflect at least 50% of infrared light received on the inner surface of the inner wall. Thus, the reflected infrared light can be used to de-ice other portions of the wall or to achieve remote de-icing.

[0017] Preferably, the inner surface of at least one of the inner wall, the outer wall or the upstream wall comprises at least two mutually offset parallel surfaces, which enables the infrared rays to be precisely focused on a portion of the wall of the air intake duct lip.

[0018] According to one aspect, the outer wall includes an inner surface configured to reflect at least 50% of infrared light received on the inner surface, so that the reflected infrared light can be used to de-ice other parts of the wall or to achieve remote de-icing.

[0019] According to one aspect, the upstream wall includes an upstream wall inner surface configured to reflect at least 50% of infrared light received on the upstream wall inner surface, so that the reflected infrared light can be used to de-ice other portions of the wall or to achieve remote de-icing.

[0020] According to one aspect, the bulkhead includes an inner surface configured to reflect at least 50% of infrared radiation received thereon. Such a bulkhead can achieve a reflective function and thereby concentrate the infrared radiation for use in deicing other portions of the wall and / or remotely.

[0021] Preferably, the infrared radiation source is offset longitudinally upstream from the first portion of the inner wall. Advantageously, this enables localized de-icing through the transparent wall of the intake duct lip. Furthermore, this optimizes the position of the first portion to focus infrared radiation for remote de-icing of the portion opposite the intake duct lip.

[0022] Preferably, the outer wall comprises at least one hot gas outlet, so that the annular cavity can be conveniently cooled by an external air flow.

[0023] According to one aspect of the present invention, the lip includes at least one circumferential transparent wall mounted on the partition wall of the annular cavity to define an annular duct, within which the infrared radiation source is mounted. Advantageously, this allows the infrared radiation source to be cooled independently of the annular cavity, allowing the annular cavity to de-ice the intake duct lip wall at an optimal temperature.

[0024] "Transparent material" refers to a material that is capable of transmitting at least 60% of infrared light received on an inner surface to an outer surface.

[0025] Preferably, the partition wall comprises at least one hot gas outlet, thereby allowing the annular duct to be cooled without interacting with the annular cavity.

[0026] Preferably, the lip comprises at least one ice detection device configured to switch off the infrared radiation source in the absence of ice.

[0027] Preferably, the infrared radiation source comprises at least one infrared emitter and at least one controller, wherein the controller is configured to control the infrared emitter based on the presence or absence of ice. Thus, when the ice layer is removed, the infrared emission can be stopped, which can in particular save energy.

[0028] Preferably, the ice detection device includes at least one detection wave transmitting source and at least one sensor, wherein the sensor is configured to detect reflection of the detection wave by the ice layer, thereby indirectly detecting the presence of ice based on the detection wave reflected by the ice layer.

[0029] The present invention relates to an air intake duct for an aircraft turbine nacelle, the nacelle extending along an axis X, wherein air flows from upstream to downstream in the nacelle, the air intake duct comprising a lip as described above. Preferably, the air intake duct comprises an upstream portion formed by the lip, and a downstream portion mounted on the lip.

[0030] The present invention also relates to a method for de-icing an air intake lip as described above, the method comprising:

[0031] turning on an infrared radiation source in the annular cavity to emit infrared rays toward an inner surface of at least one of the inner wall, the outer wall, and the upstream wall; and

[0032] At least 30% of the infrared light received on the inner surface of the wall is transmitted to the outer surface of the wall that has received the infrared light.

[0033] Localized internal heating can remove ice without completely melting it or sublimating it into water vapor, which provides a significant energy gain. Furthermore, the entire intake lip can be locally de-iced using a transparent wall.

[0034] Preferably, the method comprises detecting the presence of ice on the outer surface of the wall which has received the infrared radiation, and switching off the infrared radiation source when no ice is present.

[0035] Intermittent de-icing by infrared emission is energy-efficient, as the infrared radiation source is not continuously on. This intermittent operation is still highly efficient, as the infrared radiation source has a fast response time and the heating is locally carried out from the inside.

[0036] By means of the invention, the infrared radiation source makes it possible to de-ice the inner wall, the outer wall and the upstream wall quickly and economically, compared to the limited infrared radiation sources used in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. In the drawings, the same reference numerals are used to indicate similar objects, wherein:

[0038] Figure 1 is a longitudinal sectional view of a turbine in the prior art;

[0039] Figure 2 is a longitudinal sectional view of a turbine according to an embodiment of the present invention;

[0040] Figure 3 is an enlarged schematic diagram of the intake pipe lip of the present invention in a longitudinal half-section view;

[0041] Figure 4 is a longitudinal cross-sectional view of the air intake duct lip during long-distance deicing according to the present invention;

[0042] Figures 5A to 5C Schematic diagrams of remote external deicing, conduction internal deicing, and transmission internal deicing;

[0043] Figure 6 and Figure 7 They are respectively longitudinal and transverse schematic diagrams of the air intake pipe lip of the present invention;

[0044] Figure 8 and Figure 9 They are respectively longitudinal and transverse schematic views of the air intake pipe lip with an annular duct according to the present invention;

[0045] Figures 10A-10D and Figure 11 They are respectively longitudinal and transverse schematic diagrams of several embodiments of the air intake duct lip of the present invention;

[0046] Figure 12 is a schematic diagram of an infrared radiation source of the present invention;

[0047] Figure 13 and Figure 14 They are schematic diagrams of the ice detection device of the present invention.

[0048] It should be noted that these drawings illustrate the invention in detail to enable the invention to be realized and, of course, can be used to better define the invention if necessary. DETAILED DESCRIPTION

[0049] refer to Figure 2 , which shows a turbine 1 extending along an axis X and including a fan 11 rotatably mounted about the axis X in a nacelle including a housing 12, for accelerating an airflow F from upstream to downstream. Hereinafter, the terms upstream and downstream are defined relative to the flow direction of the airflow F. At its upstream end, the turbine 1 includes an air inlet duct 2 comprising an upstream portion 2a, referred to by those skilled in the art as a lip, and a downstream portion 2b. In this embodiment, the lip 2a is separated from the downstream portion 2b by a partition 25.

[0050] The lip 2a includes an inner wall 21 facing the axis X and an outer wall 22 opposite to the inner wall 21. The inner wall 21 and the outer wall 22 are connected by an upstream wall 23 and a partition wall 25 to define an annular cavity 24 referred to as a "D duct" by those skilled in the art. Thus, the lip 2a separates the incoming air flow F into an internal air flow FINT guided by the inner wall 21 and an external air flow FEXT guided by the outer wall 22. In the following, the terms "inside" and "outside" are defined radially relative to the axis X of the turbine 1. Similarly, the terms "inside" and "outside" are defined relative to the annular cavity 24. Therefore, each wall of the lip 2a includes an inner surface facing the annular cavity 24 and an outer surface opposite to the inner surface. In this embodiment, the turbine 1 is a turbojet engine.

[0051] A partition wall 25 , also called a front wall, is preferably installed approximately between the inner wall 21 and the outer wall 22 in the radial direction.

[0052] In this embodiment, Figure 3 As shown, the nacelle further comprises a noise attenuation plate ZA located downstream of the annular cavity 24 and as an extension of the inner wall 21. Such a noise attenuation plate ZA is well known to those skilled in the art and will not be described in detail.

[0053] According to the invention, the lip 2a comprises at least one infrared radiation source 9 located in an annular cavity 24. The inner wall 21, the outer wall 22 and / or the upstream wall 23 are made of a material that transmits at least 30% of the infrared radiation received on the inner surface to the outer surface. For the sake of clarity and brevity, such a material will be referred to hereinafter as a "translucent material".

[0054] In other words, unlike the prior art, which confines the infrared radiation source 9 to a reduced-size envelope downstream of the annular cavity 24 in order to remotely de-ice only the portion radially opposite the intake duct, the present invention makes it possible to perform local de-icing by utilizing "transparency" to heat the interface between the ice layer and the wall on which it is located.

[0055] Preferably, the infrared radiation source 9 comprises a plurality of infrared emitters, in particular diodes or infrared resistors, emitting electromagnetic radiation with a spectrum between 0.7 and 12 μm, preferably at a wavelength determined to have a maximum emissivity / absorptivity compared to ice-forming water.

[0056] According to the first embodiment, referring to Figure 3 Lip 2a comprises a translucent inner wall 21, an outer wall 22, and an upstream wall 23, which heat the ice layer by propagating infrared radiation. Thus, infrared radiation source 9 generates an infrared flow FIR that heats the outer surfaces of inner wall 21, outer wall 22, and upstream wall 23. This configuration offers numerous advantages, as it allows for efficient and convenient de-icing of inner wall 21, outer wall 22, and upstream wall 23.

[0057] In this embodiment, the inner wall 21, the outer wall 22 and the upstream wall 23 are made of a material that can transmit at least 60% of the infrared rays received on the inner surface to the outer surface. For the sake of clarity and simplicity, this material is hereinafter referred to as "transparent material".

[0058] This transparent material allows infrared light to be transmitted over long distances, specifically to the intake pipe 2 ( Figure 4 ) is heated remotely in the radially opposite portion of the intake pipe 2. As will be explained below, the inner wall 21 includes at least one first portion made of a transparent material so as to heat the radially opposite portion in the intake pipe 2.

[0059] For example, the inner wall 21 , the outer wall 22 and the upstream wall 23 are made of one or more of the following materials: glass ceramic, polyethylene, polycarbonate, polymethyl methacrylate, etc. The inner / outer surfaces may be surface treated to adjust their infrared transmission / reflection properties.

[0060] In this embodiment, the inner wall 21, the outer wall 22 and the upstream wall 23 are all made of at least translucent material, but of course only one or two of the inner wall 21, the outer wall 22 and the upstream wall 23 can be made of at least translucent material.

[0061] The advantages of de-icing according to the present invention will be explained below by comparing it with the "external" de-icing described in the prior art.

[0062] like Figure 5A As shown, for long-distance external deicing, in order to remove the ice layer G from the inner wall 21, the infrared IR needs to completely melt the ice layer G of this thickness. The infrared emission time is long and the power is high, which consumes a lot of energy.

[0063] refer to Figure 5B For an opaque wall including a material that can conduct at least 30% of the infrared rays received on the inner surface to the outer surface, the infrared rays IR heat the inner wall 21, causing the temperature to rise. The ice layer G melts slowly by heat conduction and consumes a lot of energy.

[0064] refer to Figure 5C As shown, for translucent or transparent walls, infrared radiation (IR) directly reaches the interface between the ice layer G and the inner wall 21, achieving faster localized heating. A liquid water film or water vapor forms between the ice layer G and the inner wall 21, facilitating its detachment. In other words, compared to the prior art, de-icing is achieved without melting the entire thickness of the ice layer, accelerating the removal of the ice layer G. The present invention allows for faster removal of the ice layer G while using less energy. In practice, during the de-icing process, the ice layer G directly receives infrared radiation, and the wavelength of this infrared radiation has been determined to have the maximum emissivity / absorption relative to ice-forming water.

[0065] Advantageously, the translucent wall filters only a small fraction of the radiant energy, leaving the interface between the ice layer and the wall exposed to infrared radiation almost instantaneously. Consequently, the ice at this interface melts very quickly. Since it does not rely on the time it takes for convection to develop or on heating the wall through conduction, the response time is nearly instantaneous. The wall temperature at lip 2a is maintained above 0°C, preventing ice formation.

[0066] According to one aspect of the present invention, referring to Figure 6 and 7 The lip 2a includes at least one ventilation inlet E1 and one ventilation outlet S1, so that the ventilation airflow can flow in the annular cavity 24, thereby cooling the infrared radiation source 9. Preferably, the ventilation inlet E1 and the ventilation outlet S1 are formed in the outer wall 22, specifically as Figure 7 Part of the external air flow is sucked in through the ventilation inlet E1, flows in the annular cavity 24 in contact with the infrared radiation source 9, and then flows out through the ventilation outlet S1. Figure 7 The lip 2a comprises at least one accelerating element 8, such as a fan, to accelerate the ventilation air flow FAV in the annular cavity 24 and thereby improve the cooling efficiency, thereby avoiding overheating of the infrared radiation source 9.

[0067] According to another aspect of the present invention, referring to Figure 8-9 The lip 2a includes at least one circumferential transparent wall 81 mounted on the inner surface 25i of the partition wall 25 in the annular cavity 24, thereby defining an annular duct 80. The infrared radiation source 9 is mounted in the annular duct 80. In other words, the infrared radiation source 9 is not mounted directly opposite the inner surfaces of the inner wall 21, the outer wall 22, and the upstream wall 23, but is instead installed in the annular duct 80 so that it can be ventilated independently of the annular cavity 24. This is very advantageous for effectively cooling the infrared radiation source 9 by maintaining a low temperature in the annular duct 80, thereby allowing the temperature in the annular cavity 24 to be higher, ensuring optimal de-icing of the inner wall 21, the outer wall 22, and the upstream wall 23.

[0068] Similar to the above, refer to Figure 9 The annular duct 80 includes at least one ventilation inlet E1 and one ventilation outlet S1, so that the ventilation airflow FAV can flow in the annular cavity 80, thereby cooling the infrared radiation source 9. Preferably, the ventilation inlet E1 and the ventilation outlet S1 are formed on the partition wall 25, specifically, as shown in FIG. Figure 9 As shown, the radial relative position. Optionally, refer to Figure 9 The lip 2a comprises at least one accelerating member 8, such as a fan, to accelerate the ventilation airflow in the annular duct 80 and thereby improve cooling.

[0069] According to one aspect of the present invention, referring to Figure 10A The partition wall 25 includes an inner surface 25i configured to reflect at least 50% of the infrared rays received on the inner surface. For the sake of clarity and brevity, this inner surface will be referred to as a "semi-reflective surface" hereinafter.

[0070] The partition wall 25 allows infrared rays IR received in the annular cavity 24 to be reflected, thereby guiding the infrared rays IR and enabling optimal de-icing of the inner wall 21, the outer wall 22, and the upstream wall 23. In other words, any infrared rays IR emitted by the infrared radiation source 9 generate reflected infrared rays IR2 that first come into contact with the partition wall 25 and then with the inner wall 21, the outer wall 22, or the upstream wall 23. In this embodiment, the inner wall 21, the outer wall 22, or the upstream wall 23 is at least translucent.

[0071] The infrared radiation source 9 emits omnidirectionally and the partition 25 enables the infrared radiation to be concentrated on the wall to be de-iced. Advantageously, the use of such a partition 25 makes it possible to adjust the incidence of the infrared radiation by adjusting the shape of the partition 25 and by judiciously positioning the infrared radiation source 9 in the annular cavity 24.

[0072] To optimally focus infrared radiation IR, partition wall 25 preferably includes an inner surface 25i configured to reflect at least 80% of the infrared radiation received thereon. For the sake of clarity and brevity, such an inner surface will be referred to below as a "reflective surface." Similarly, an inner surface configured to reflect less than 30% of the infrared radiation received thereon will be referred to below as a "non-reflective surface." The inner surface 25i of partition wall 25 thus performs an infrared radiation reflection function.

[0073] According to one aspect of the present invention, referring to Figure 10B The outer wall 22 also includes a semi-reflective or reflective inner surface 22i to reflect infrared radiation IR toward the annular cavity 24, in particular toward the semi-transparent (or transparent) and non-reflective upstream wall 23 and the inner wall 21. This, in turn, allows radiation outside the annular cavity 24 to de-ice another portion of the lip 2a from the outside.

[0074] According to an aspect of the invention not shown, upstream wall 23 also includes a semi-reflective inner surface to reflect infrared radiation toward annular cavity 24, and in particular toward the semi-transparent (or transparent) and non-reflective inner wall 21. This allows the infrared radiation to be concentrated toward inner wall 21, where ice is most likely to accumulate. Furthermore, this allows radiation from outside annular cavity 24 to de-ice another portion of lip 2a from the outside.

[0075] According to another aspect of the present invention, referring to Figure 10C The inner wall 21 includes a first portion 21a made of a translucent (or transparent) and non-reflective material and a second portion 21b including an inner surface that is at least semi-reflective, so as to promote infrared transmission through the first portion 21a while achieving de-icing of other portions of the lip 2a by allowing at least 30% of the infrared light to be transmitted. Figure 10C , the first portion 21a is the downstream portion of the inner wall 21 so as to benefit from the angle of incidence that achieves an optimal external de-icing effect.

[0076] like Figure 11 As shown, only the first portion 21a of the inner wall 21 is non-reflective and forms an outlet for infrared IR reflected into the annular cavity 24. In this embodiment, the infrared radiation source 9 is offset in the longitudinal direction from the first portion 21a of the inner wall 21. In this embodiment, reference is made to Figure 11, infrared radiation source 9 (position X9) is located upstream of first portion 21a of inner wall 21 (position X21a), i.e., near upstream wall 23. This axial offset is advantageous for a number of reasons. First, the proximity of infrared radiation source 9 and upstream wall 23 enables optimal de-icing of the adjacent upstream wall 23, inner wall 21, and outer wall 22, which are located around infrared stream FIR transmitted through lip 2a. Furthermore, first portion 21a of inner wall 21 is optimally positioned to collect infrared radiation IR2 reflected from multiple different reflective surfaces and focus it onto a distant, preferably diametrically opposed, wall for long-range external de-icing. This configuration advantageously enables long-range external de-icing while simultaneously achieving localized internal de-icing.

[0077] According to another aspect of the present invention, referring to Figure 10D The semi-reflective or reflective inner surface may comprise a plurality of surfaces 26, ie Fresnel surfaces, offset from one another in order to optimally direct the reflected infrared IR. The surfaces 26 are preferably conical. Figure 10D 2 , the inner wall 21 including the Fresnel surface 26 is shown, but such a surface may of course be formed on one or more of the inner wall 21 , the outer wall 22 , the upstream wall 23 and the partition wall 25 .

[0078] refer to Figure 12 Infrared radiation source 9 includes a plurality of infrared emitters and a controller 91. The plurality of infrared emitters are specifically infrared diodes 90 or any other infrared lamps. Controller 91 is configured to control infrared diodes 90 based on the presence or absence of ice. Preferably, infrared diodes 90 and controller 91 are mounted on the same electronic board 92. Controller 91 is, for example, a processor connected to electronic board 92.

[0079] refer to Figure 13 and 14 , which shows an ice detection device 7, which includes an emission source 70, specifically a light emitting diode, for detecting a wave RD, and a detector 71 for detecting a reflection of the detection wave RD by the ice layer G. Figures 13 to 14 The emission source 70 and detector 71 of the detection wave RD are mounted on an electronic board 73 with a controller 74. The ice detection device 7 preferably includes a power supply (not shown). The wavelength of the detection wave RD is preferably different from the wavelength of the infrared (IR) waves used for de-icing. The detection wave RD is preferably an electromagnetic wave with a wavelength preferably between 0.7 and 1.7 μm. This type of electromagnetic wave is advantageous because the ice layer G has a very high reflectivity in this wavelength range.

[0080] Preferably, the ice detection devices 7 are distributed around the periphery of the upstream wall 23 .

[0081] Preferably, the ice detection device 7 is connected to the infrared radiation source 9 to control the infrared IR emission according to the presence of ice. For example, the controller 74 of the emission source 70 of the detection wave RD is configured to exchange data with the controller 91 of the infrared radiation source 9.

[0082] In this embodiment, ice detection device 7 further includes a filter 72, which is arranged in front of detector 71 to block stray radiation, specifically stray radiation from infrared radiation source 9 used for de-icing. Preferably, filter 72 has a bandwidth between 0.7-1.7 μm and is capable of absorbing most of the infrared radiation emitted by these other sources and having an energy spectrum outside the 1.7 μm wavelength.

[0083] In this embodiment, detector 71 is configured to measure detection wave RD along one direction to determine the portion of detection wave RD reflected by ice. This detector 71 is therefore sensitive to electromagnetic waves. This detector 71 allows for direct detection of the ice layer G on the outer surface of the wall. In practice, the larger the portion of detection wave RD reflected, the thicker the ice layer G, and the more detection wave RD it reflects. Conversely, the smaller the portion of detection wave reflected, the thinner the ice layer G, and the more detection wave RD it transmits. Preferably, lip 2a includes a plurality of detectors 71 arranged around the periphery of lip 2a.

[0084] Optionally, the ice detection device 7 comprises one or more piezoelectric sensors arranged in the annular cavity 24 in order to detect Lamb waves in the wall to be de-iced and to infer the presence of ice therefrom.

[0085] Optionally, the ice detection device 7 comprises one or two infrared measuring cameras, each equipped with a wide-angle lens, which can be used to measure the presence or absence of ice. Such cameras are preferably arranged outside the annular cavity 24 of the lip 2a.

[0086] The various embodiments of the invention will now be described with respect to de-icing of the outer wall 22, but the principles are equally applicable to the translucent or transparent inner wall 21 or upstream wall 23. However, better results can be obtained with a transparent wall.

[0087] Firstly, in the event of ice formation, the infrared radiation source 9 can be switched on substantially continuously in order to melt the ice layer G and keep it in liquid form until it is sucked in by the fan 11 .

[0088] Infrared radiation source 9 makes it possible to heat the entire surface of outer wall 22 to a positive temperature, for example 5°C, in order to maintain liquid water upstream of fan 11. Advantageously, ice layer G is not evaporated, thus achieving energy savings. This solution is particularly noteworthy for the small surface area that needs to be kept at a positive temperature, thus reducing the energy required.

[0089] Optionally, the infrared radiation source 9 may be turned on intermittently to separate the ice layer into a plurality of solid ice blocks.

[0090] Because the infrared radiation source 9 has a short response time, reaching maximum power in approximately one second, for example, intermittent de-icing can be performed to reduce energy consumption. In practice, the infrared radiation source 9 can be turned off for a predetermined period, for example, one to thirty seconds, to allow a thin layer of ice to remain. The infrared radiation source 9 is then turned on for, for example, one to thirty seconds to loosen the ice layer from the wall by melting only the thin interface between the ice layer and the wall. The small fragments of ice layer G are then carried away by the surrounding airflow and absorbed by the turbine. Since only the interface with the wall needs to be melted, the majority of the ice layer remains solid, resulting in significant energy gains from intermittent use.

[0091] The infrared energy density can be evenly distributed or intensified by focusing the infrared radiation, specifically in a grid with a very small grid size, such as about 10 mm. Gridded focusing advantageously allows for the sizing of ice fragments and helps facilitate their removal by airflow.

[0092] As will be explained below, the activation control of the infrared radiation source 9 is determined based on the detection of ice. Alternatively, this control can be performed by analyzing the temperature of the annular cavity 24. For this purpose, the lip 2a can include one or more temperature sensors arranged on the inner or outer surface of the wall to be de-iced.

[0093] exist Figure 13 In the example, there is an ice layer G on the outer surface of outer wall 22. The emission source 70 emits a detection wave RD toward outer wall 22. Part of the detection wave is reflected by the ice layer and detected by the detector 71. Thus, the reflected detection wave RD passes through outer wall 22 twice. Advantageously, due to its high transmission rate in this wavelength range, the absorption loss in the material of outer wall 22 is very low.

[0094] In this embodiment, filter 72 removes any stray infrared radiation used to detect the presence of ice. Controller 74 compares the measured value with a predetermined threshold to determine the presence of ice. Preferably, the threshold is calibrated based on feedback.

[0095] In other words, when few reflected RD detection waves are detected ( Figure 14 ), based on which it is inferred that the ice layer G has disappeared. Preferably, when the controller 74 detects that there is no ice, the controller 74 of the ice detection device 7 sends a stop instruction to the controller 91 of the emission source 9, which advantageously reduces energy consumption.

[0096] When a new layer of ice G appears, the light-emitting diodes 90 of the infrared radiation source 9 are switched on again. The switch-on delay time is calibrated to avoid the formation of thick ice layers. For example, the delay time is parameterized according to the transmissivity and transmission properties of the material of the wall to be de-iced.

[0097] Advantageously, such a de-icing device achieves a mass gain compared to conventional pneumatic de-icing devices. Furthermore, the de-icing power required for translucent or transparent de-icing is reduced by a factor of 5 to 20, which offers significant energy advantages. In particular, it is not necessary to sublimate all solid ice into water vapor, as is done in the prior art.

[0098] The nacelle's complexity is also reduced, and the space dedicated to mounting noise-attenuating panels is not compromised. Therefore, noise-attenuating properties are maintained. Furthermore, the presence of transparent sections in the interior wall enables a combination of localized heating and remote heating, thereby improving the quality and speed of de-icing. Various semi-reflective or reflective interior surfaces act as focussers, optimizing the use of infrared radiation sources for remote de-icing.

Claims

1. A lip (2a) of an air inlet duct (2) of an aircraft turbine nacelle (1), said nacelle extending along an axis (X) in which an air flow (F) flows from upstream to downstream, said lip (2a) extending around the axis (X) and comprising an inner wall (21) facing the axis (X) and an outer wall (22) opposite said inner wall (21), said inner wall (21) and said outer wall (22) being connected by an upstream wall (23) and a partition wall (25) to define an annular cavity (24), in which at least one infrared radiation source (9) is housed, characterized in that: At least one of the inner wall (21), the outer wall (22) and the upstream wall (23) is made of a material configured to transmit at least 30% of the infrared rays received on the inner surface of the wall to the outer surface of the wall; the lip (2a) includes at least one circumferential transparent wall (81), which is mounted on the partition wall (25) of the annular cavity (24) to define an annular duct (80), and the infrared radiation source (9) is located in the annular duct (80).

2. The lip (2a) according to claim 1, characterized in that The inner wall (21) comprises at least one first portion (21a) made of a material configured to transmit at least 60% of infrared light received on the inner surface of the wall to the outer surface of the wall.

3. The lip (2a) according to claim 1, characterized in that The inner wall (21) includes at least one second portion (21b), the second portion (21b) including an inner surface of the inner wall (21), the inner surface of the inner wall being configured to reflect at least 50% of infrared rays received on the inner surface of the inner wall (21).

4. The lip (2a) according to claim 1, characterized in that The outer wall (22) includes an inner surface (22i) of the outer wall (22), and the inner surface (22i) of the outer wall is configured to reflect at least 50% of infrared rays received on the inner surface (22i) of the outer wall (22).

5. The lip (2a) according to claim 1, characterized in that The upstream wall (23) includes an inner surface (23i) of the upstream wall (23), and the inner surface (23i) of the upstream wall is configured to reflect at least 50% of infrared rays received on the inner surface (23i) of the inner wall (23).

6. The lip (2a) according to claim 1, characterized in that The partition wall (25) includes an inner surface (25i) of the partition wall (25), and the inner surface (25i) of the partition wall is configured to reflect at least 50% of infrared rays received on the inner surface (25i) of the partition wall (25).

7. The lip (2a) according to claim 2, characterized in that The infrared radiation source (9) is longitudinally offset upstream from the first portion (21a) of the inner wall (21).

8. The lip (2a) according to claim 1, characterized in that An ice detection device (7) is included, and the ice detection device (7) is configured to turn off the infrared radiation source (9) when there is no ice.

9. The lip (2a) according to claim 1, characterized in that The outer wall (22) or the upstream wall (23) is made of a material configured to transmit at least 30% of infrared light received on the inner surface of the wall to the outer surface of the wall.

10. An air intake duct of an aircraft turbine nacelle (1), said nacelle extending along an axis (X), wherein the air flow (F) flows from upstream to downstream, characterized in that The air inlet duct comprises a lip (2a) as claimed in any one of claims 1 to 9.

11. A method for de-icing a lip (2a) according to any one of claims 1 to 9, characterized in that The method comprises: Turning on the infrared radiation source (9) in the annular cavity (24) to emit infrared rays onto the inner surface of at least one of the inner wall (21), the outer wall (22) and the upstream wall (23); and At least 30% of the infrared light received on the inner surface of the wall is transmitted to the outer surface of the wall where the infrared light was received.

12. The deicing method according to claim 11, wherein: The method comprises detecting the presence of ice on the outer surface of the wall that has received the infrared radiation, and switching off the infrared radiation source (9) when there is no ice.

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