ANTI-FROSTING AND DEFROSTING DEVICE

Abstract

A device (1) for anti-icing and de-icing an aircraft engine nacelle, the nacelle comprising an air inlet having a lip (2), the lip (2) having an internal profile (4). The device (1) comprises at least one heating resistive element wound on a preformed element (6) with the internal profile (4) of the lip (2), and means for maintaining pressure on the preformed element (6) against the internal profile (4). Figure to be published with the abbreviation: Fig. 1

Description

Title of the invention: ANTI-FROSTING AND DEFROSTING DEVICE technical field

[0001] The invention relates to the field of anti-icing and de-icing devices for an aircraft engine nacelle. STATE OF PRIOR ART

[0002] In the aeronautical field, it is well known that a nacelle is a complex system that surrounds an aircraft engine.

[0003] A nacelle is composed of several cowlings, incorporates a thrust reverser and has an air inlet. Typically the air inlet is composed of an outer body, an inner body, a lip, a front partition and a rear partition.

[0004] In operation, when the turbomachine is a turbofan engine, the airflow passing through the air inlet lip passes through a fan blade and then splits into a primary airflow which enters the turbomachine and a secondary airflow which flows around the turbomachine.

[0005] In the case where the turbomachine is a turboprop, for example of the Open Rotor Pusher type (i.e. whose propulsion propellers are located downstream of the turbomachine, with reference to the direction of airflow around it), the entire airflow that passes through the air inlet lip supplies the turbomachine.

[0006] It is specified that the present invention does not apply only to the aforementioned examples of turbomachinery, but also to any type of turbomachine architecture having a nacelle with an air inlet requiring an anti-icing and de-icing function.

[0007] The role of the air inlet lip on a propulsion system is to supply the engine with air throughout its operating range, while minimizing losses and drag. However, the lip is in direct contact with the external environment of the propulsion system and is subject to external stresses, such as icing. Ice formation on the lip can lead to a reduction in its efficiency and the detachment of ice sheets which, by passing through the air inlet, pose a risk of damage to the engine, and in particular to the fan blades or propellers.

[0008] In order to limit icing phenomena on the air inlet lip of a propulsion assembly, an NAI (Nacelle Anti-Icing) anti-icing system and lip defrosting is implemented. This is typically a system that draws in hot air to heat the outer surface of the air inlet lip.

[0009] A first known solution consists of drawing anti-icing (de-icing) air from a high-pressure (HP) compressor of the turbomachine and then conveying it through a pipe to anti-icing (and de-icing) ducts extending to the lip. From a performance standpoint, this hot air anti-icing (and de-icing) function results in the need to draw air from the HP compressor, leading to a loss of working air flow for the engine and therefore a loss of engine performance.

[0010] A second known solution uses heating mats bonded to the lip and coupled with remote power electronics. This solution avoids affecting the engine's airflow. However, this second solution requires dissipating the power electronics' heat losses using heavy and bulky heat sinks. Furthermore, bonding the mats complicates system maintenance and may necessitate a complete replacement of the air intake. In addition, the use of remote power electronics means that the power electronics' heat losses are permanently wasted, whereas this energy could contribute to the nacelle's anti-icing and de-icing.

[0011] In this context, it is therefore necessary to provide an anti-icing and de-icing system for an aircraft engine nacelle, which is simple to install and maintain, which has optimal efficiency, without affecting engine performance. Description of the invention

[0012] To this end, according to a first aspect, an anti-icing and de-icing device for an aircraft engine nacelle is proposed, the nacelle comprising an air inlet having a lip, the lip having an internal profile. The device comprises at least one heating resistive element wound on an element preformed to the internal profile of the lip, and means for maintaining pressure on the preformed element against the internal profile.

[0013] In a particularly ingenious way, the use of a pre-formed element on which the heating resistive element is wound makes it easier to install and maintain the anti-icing system, without affecting engine performance.

[0014] According to a particular arrangement, the heating resistive element comprises at least one resistive wire and / or at least one heating mat.

[0015] According to a particular arrangement, the device includes a switchable power module that supplies the heating resistive element, the power module being installed directly in the air intake of the nacelle, the power module preferably being of the type with redundant switches.

[0016] According to a particular arrangement, the, or each, switch of the power module is a power semiconductor selected from power semiconductors of the type Sic-Mosfet, Mosfet, thyristor, SiC, GaN or insulated gate bipolar transistor (IGBT).

[0017] According to a particular arrangement, the means for maintaining pressure on the preformed element on the internal profile include at least one clamp, the means for maintaining pressure on the preformed element on the internal profile preferably including at least one clamp compression spring.

[0018] According to a particular arrangement, the means for maintaining pressure on the preformed element on the internal profile include at least one stud-nut assembly allowing the clamp to be adjusted and maintained under pressure.

[0019] According to a particular arrangement, the device includes a thermally conductive filling pad positioned between the internal profile and the preformed element.

[0020] According to a particular arrangement, the filling pad is a glass fiber reinforced polymer comprising rubber.

[0021] According to another aspect, a nacelle for an aircraft engine is also proposed comprising at least one device according to the invention.

[0022] According to another aspect, an aircraft comprising at least one nacelle according to the invention is also proposed. Brief description of the drawings

[0023] The features of the invention mentioned above, as well as others, will become clearer upon reading the following description of at least one exemplary embodiment, said description being made in relation to the accompanying drawings, among which:

[0024] [Fig-1] schematically illustrates a lip of a gondola comprising a device anti-freezing and defrosting according to an example;

[0025] [Fig.2] schematically illustrates a power module according to a first embodiment;

[0026] [Fig.3] schematically illustrates a power module according to a second embodiment;

[0027] [Fig.4] schematically illustrates a power module according to a third embodiment;

[0028] [Fig.5] schematically illustrates a power module according to a fourth embodiment;

[0029] [Fig.6] schematically illustrates a step in the installation of a lip of a nacelle including a de-icing device;

[0030] [Fig.7] schematically illustrates a subsequent step in the installation of a lip of a nacelle comprising a de-icing device.

[0031] DETAILED DESCRIPTION OF IMPROVEMENTS

[0032] Anti-freezing and defrosting device

[0033] With reference to [Fig. 1], according to a first aspect, a device 1 for anti-icing and de-icing an aircraft engine nacelle is proposed, comprising an air inlet having a lip 2. The term "anti-icing prevention" may also be used hereafter to refer to the anti-icing function. The lip 2 has an internal profile 4. The device 1 comprises at least one heating resistive element wound on a preformed element 6 with the internal profile 4 of the lip 2, and means for maintaining pressure on the preformed element 6 against the internal profile 4.

[0034] According to a particular arrangement, the device 1 also includes temperature sensors for monitoring the temperature of the lip 2 and of one or more components of the defrosting device 1.

[0035] Preformed element

[0036] As previously stated, the device 1 comprises a preformed element 6 on which a resistive element is wound (which will be described below).

[0037] According to a particular arrangement, the preformed element 6 can be made of mica. Thus, the resistive element can be wound on the preformed mica element 6, and can be insulated with mica sheets.

[0038] According to a further particular arrangement, the preformed element 6 may have teeth to facilitate the winding of the resistive element.

[0039] In addition, according to a particular arrangement, the preformed element 6 incorporates connectors 34 (preferably three), which allow the power module 10 to be supplied with electrical current from a 115 VAC three-phase network of the aircraft.

[0040] Resistive element and power module

[0041] As previously stated, the device 1 includes a resistive element. The resistive element can be a resistive wire 8a (heating) or a heating mat 8b.

[0042] The device 1 may include power components or a power module 10 with a switch 12 that supplies the heating resistive element installed on the lip 2, and a control module 32. The control module 32 may be installed in the front frame or in a blower housing. The power module 10 may be installed directly in the air intake of the nacelle. This arrangement reduces heat loss and results in a compact and efficient device.

[0043] According to the examples presented here, the power module 10 has redundant switches 12 (see Figs 2-5) which guarantees greater resilience of the device in the face of possible failures.

[0044] According to an example not shown, the power module 10 in its entirety can also be redundant, to further increase the resilience and therefore the availability rate of the device (i.e. to increase continuity of service in case of failure).

[0045] The, or each, switch 12 of the power module 10 can be a power semiconductor selected from power semiconductors of the type Sic-Mosfet, Mosfet, thyristor, SiC, GaN or, insulated gate bipolar transistor (IGBT).

[0046] Figure 2 schematically illustrates an electrical architecture of the power module 10 according to a first embodiment. In this embodiment, the power module 10 uses SiC power semiconductors and incorporates a control synchronized to the zero-crossing of the aircraft's electrical network. This synchronization prevents harmonic interference in the aircraft's electrical network.

[0047] According to this first embodiment, the power module 10 also includes temperature protection.

[0048] According to this first embodiment, the power module 10 (and therefore the device) is supplied by a single three-phase electrical network 14a-14b-14c of the aircraft.

[0049] Figure 3 schematically illustrates a second embodiment in which the heating resistive element comprises redundant resistive wires 8a. According to this second embodiment, the power module 10 is supplied by a three-phase electrical network 14a-14b-14c of the aircraft. In the event of a simple failure of the power electronics on one of the phases, it may then be necessary, for example, to connect phase 14a to connector 16a. Typically, according to this embodiment, the electrical network harness can be changed by a maintenance operator while the aircraft is on the ground.

[0050] Figure 4 schematically illustrates a third embodiment, in which the heating resistive element comprises redundant resistive wires 8a. According to this third embodiment, the power module 10 is alternately powered by two separate three-phase electrical networks 14a-14b-14c and 18a-18b-18c of the aircraft. This arrangement increases the resilience of the device by ensuring continuous operation of the device in the event of a failure of one of the aircraft's electrical networks.

[0051] Figure 5 schematically illustrates a fourth embodiment, in which the heating resistive element comprises heating mats 8b. According to this third embodiment, the power module is supplied alternately by two electrical networks The aircraft has separate three-phase 14a-14b-14c and 18a-18b-18c power supplies. This arrangement increases the resilience of the system by ensuring continued operation in the event of a failure in one of the aircraft's electrical networks.

[0052] Means of maintaining pressure

[0053] As previously stated, the device 1 also includes means for maintaining pressure on the preformed element 6 on the internal profile 4.

[0054] According to the example presented here, in Figs. 1, 6 and 7, the means for maintaining pressure include in particular a clamp 20.

[0055] As schematically shown in Figs. 1, 6 and 7, the clamp 20 is positioned against the preformed element to press it and hold it against the internal profile 4 of the lip 2.

[0056] According to a particular arrangement, shown schematically in [Fig. 6], the clamp 20 has a maintenance handle 22. The handle 22 facilitates positioning of the clamp 20 during installation and also facilitates removal of the clamp 20 during maintenance.

[0057] The means for applying pressure may also include compression springs 24 for the clamp 20. The compression springs 24 make it easier to install the clamp 20 by applying a preload on the clamp 20 while it is locked in position.

[0058] As schematically shown in [Fig. 7], the means for maintaining pressure may also include a stud 26 - nut 28 assembly for adjusting and maintaining pressure on the clamp 20. In other words, the stud 26 - nut 28 assembly allows the clamp 20 to be locked in position. As schematically shown in [Fig. 7], the stud 26 has one end pressed against the clamp 20 and another free end onto which the nut 28 is screwed. Typically, an inner wall 30 of the nacelle can serve as a translational locking device for the nut 28. It is specified that the stud 26 - nut 28 assembly may be replaced by a screw-nut assembly or an assembly comprising a plate fixed to one end of a threaded rod and a nut.This type of assembly (stud 26 - nut 28), or its alternatives, is particularly advantageous because it allows for precise adjustment of the pressure holding force while being irreversible (rotating the nut 28 moves the stud 26 translationally, but the reverse is not possible). Furthermore, the stud 26 - nut 28 assembly is easily disassembled, making maintenance operations particularly simple.

[0059] In a particularly advantageous way, a thermally conductive filling pad can be positioned between the internal profile 4 and the preformed element 6. The filling pad makes it possible to fill any gap between the preformed element and the internal profile of the lip.

[0060] According to a particular arrangement, the filling pad is a glass fiber reinforced polymer, comprising rubber and a thermal interface between the internal profile 4 and the preformed element 6. The filling pad is adapted to provide a thermal interface between the internal profile 4 and the preformed element 6. The filling pad makes it possible to bridge differences in geometry and / or roughness between the internal profile 4 and the preformed element 6.

[0061] Installation method

[0062] Typically, device 1 can be installed in the following manner: - The filling pad is positioned on the internal profile 4 of the lip 2; - The pre-formed element 6 is applied against the filling pad; - The clamp 20 is pressed against the pre-formed element 6 with the compression springs 24; - The stud 26 - nut 28 assembly is positioned and adjusted to maintain the clamp 20 and the preformed element 6 in compression against the internal profile 4; - The power module 10 is preferably positioned on the upper lip, and is connected to the heating resistive element and the aircraft's electrical network.

[0063] Gondola

[0064] According to another aspect, a nacelle for an aircraft engine comprising device 1 is also proposed.

[0065] Aircraft

[0066] According to another aspect, an aircraft is proposed comprising the nacelle which includes the device 1.

Claims

Demands

1. Device (1) for anti-icing and de-icing of an aircraft engine nacelle, the nacelle comprising an air inlet having a lip (2), the lip (2) having an internal profile (4), the device (1) being characterized in that it comprises at least one heating resistive element wound on a preformed element (6) with the internal profile (4) of the lip (2), and means for maintaining pressure on the preformed element (6) on the internal profile (4).

2. Device (1) according to claim 1, wherein the heating resistive element comprises at least one resistive wire (8a) and / or at least one heating mat (8b).

3. Device (1) according to any one of the preceding claims, comprising a power module (10) with switches (12) which powers the heating resistive element, the power module (10) being installed directly in the air intake of the nacelle, the power module (10) preferably being of the type with redundant switches (12).

4. Device (1) according to claim 3, wherein the, or each, switch (12) of the power module (10) is a power semiconductor selected from Sic-Mosfet, Mosfet, thyristor, SiC, GaN or insulated gate bipolar transistor (IGBT) type power semiconductors.

5. Device (1) according to any one of the preceding claims, wherein the means for maintaining pressure on the preformed element (6) on the internal profile (4) comprise at least one clamp (20), the means for maintaining pressure on the preformed element (6) on the internal profile (4) preferably comprising at least one clamp compression spring (24).

6. Device (1) according to claim 5, wherein the means for maintaining pressure on the preformed element (6) on the internal profile (4) comprise at least one stud (26) - nut (28) assembly for adjusting and maintaining pressure on the clamp (20).

7. Device (1) according to any one of the preceding claims, comprising a thermo-conductive filling pad positioned between the internal profile (4) and the preformed element (6).

8. Device (1) according to claim 7, wherein the filling pad is a glass fiber reinforced polymer comprising rubber.

9. Aircraft engine nacelle comprising at least one device (1) according to any one of claims 1 to 8.

10. Aircraft comprising at least one nacelle according to claim 9.