Air intake lip for an aircraft nacelle

Abstract

The invention relates to an air intake lip (7) which is annular about a longitudinal axis and comprises: - an annular inner wall (8), - an annular outer wall (9) extending coaxially around the inner wall (8), - an annular inner cavity (11) delimited radially by the inner and outer walls (8, 9), - an annular partition (12) radially connecting the inner and outer walls (8, 9) and axially closing the inner cavity (11), and - an anti-icing device (13) received at least partially in the inner cavity (11) and comprising an annular inner passage (14) for circulation of hot air (A1), characterized in that the inner passage (14) is delimited by the partition (12) and an annular plate (15) arranged in the inner cavity (11) facing the partition (12) and connected to the partition (12).

Description

[0001] DESCRIPTION

[0002] TITLE: AIR INTAKE LIP FOR AN AIRCRAFT NACELLE

[0003] Technical field of the invention

[0004] The invention relates to the field of air inlet lips for aircraft nacelles.

[0005] The invention relates in particular to the field of air inlet lips comprising an anti-icing device, i.e. protection against frost.

[0006] Technical background

[0007] The prior art is illustrated by documents CN-U-215333139, US-A-5011098, EP-A1-3216697, FR-3145926, US-A1-2019 / 112065 and US-A1-2002 / 139900.

[0008] An aircraft propulsion system typically includes a turbomachine and a nacelle extending around the turbomachine.

[0009] The turbomachine generally extends along and around a longitudinal axis. It comprises a gas generator which typically includes, from upstream to downstream in the direction of gas flow in the turbomachine, a low-pressure compressor, a high-pressure compressor, a gas combustion chamber, a high-pressure turbine and a low-pressure turbine.

[0010] The rotor of the low-pressure compressor is typically connected to the rotor of the low-pressure turbine via a low-pressure shaft. The rotor of the high-pressure compressor, on the other hand, is connected to the rotor of the high-pressure turbine via a high-pressure shaft.

[0011] The turbomachine further includes a fan located upstream of the gas generator. The fan comprises a rotor driven in rotation about its longitudinal axis by a fan shaft. The fan further includes blades extending radially from the disk.

[0012] The fan draws in an airflow that splits downstream into a primary and a secondary airflow. The secondary airflow flows in an annular secondary channel, and the primary airflow flows in an annular primary channel surrounded by the secondary channel. The secondary airflow is responsible for the majority of the turbomachine's thrust. The primary airflow is compressed in the compressors and then mixed with fuel in the combustion chamber. The gases produced by combustion then power the turbines, driving the low-pressure shaft and, consequently, the low-pressure compressor.

[0013] The nacelle is annular and extends around and along the longitudinal axis. The nacelle typically includes an annular air inlet lip extending around the longitudinal axis. The air inlet lip comprises an annular inner wall and an annular outer wall situated coaxially around the inner wall.

[0014] The gondola further comprises an internal cavity which is radially delimited by the internal and external walls and a partition which extends radially between the internal and external walls and which axially closes the internal cavity.

[0015] Propulsion systems are subject to the risk of frost and even ice formation. Indeed, the secondary airflow temperature, which can often reach sub-zero levels, combined with air humidity, creates favorable conditions for frost and, ultimately, ice formation. For example, the air inlet lips of the nacelles are particularly susceptible to frost or ice formation. Such phenomena are disruptive to aircraft propulsion systems, as they can unbalance these systems by creating air distortions or by damaging the turbomachine's fan components through impact. In this context, document W0-A1-2016 / 005711 proposes equipping the nacelles with an anti-icing device comprising an annular tube located within the internal cavity.The tube has an internal passage for supplying hot air to the internal cavity, allowing it to heat the inner and outer walls of the nacelle and thus limiting or even preventing the risk of frost or ice formation. According to this document, the tube is supported by the bulkhead and is attached to it by connecting plates.

[0016] Although such a solution reduces the risk of frost or ice formation, it has some drawbacks. Because the tube is attached to the partition, the solution is complex to implement, particularly the tube installation, which is not easy. Also, the attached tube increases the weight of the air inlet lip.

[0017] Furthermore, such a tube requires a significant air intake flow rate from the turbomachine, which can impact the turbomachine's performance and fuel consumption, particularly during de-icing phases. Since the tube is located within the internal cavity, the cavity must be large enough to accommodate it. However, nacelle configurations are evolving, tending to move the bulkhead upstream, thus reducing the size of the internal cavity. With the reduced internal cavity dimensions, positioning the tube within it becomes more difficult. Consequently, there is a need for a compact, lightweight, and easily manufactured air intake lip for the nacelle of aircraft with a low risk of frost or ice formation, one that maintains the turbomachine's performance.

[0018] Summary of the invention

[0019] To this end, the invention proposes an air inlet lip for an aircraft nacelle, the air inlet lip being annular around a longitudinal axis and comprising:

[0020] - an annular inner wall centered on the longitudinal axis, - an annular outer wall extending coaxially around the inner wall,

[0021] - an internal annular cavity delimited radially by the internal and external walls,

[0022] - an annular partition radially connecting the internal and external walls and axially closing the internal cavity, and

[0023] - an anti-icing device housed at least partly in the internal cavity and comprising an internal annular passage for the circulation of hot air.

[0024] The air inlet lip is remarkable in that the internal passage is delimited by the partition and an annular plate disposed in the internal cavity opposite the partition and connected to the partition.

[0025] The air inlet lip also includes a thermal insulation strip located between the partition and the plate.

[0026] According to the invention, the internal passage for the circulation of hot air within the internal cavity is formed or delimited by the partition and the plate. The partition and the plate therefore cooperate to form this internal passage.

[0027] Thanks to such a configuration, it is possible to do away with a tube dedicated to the circulation of hot air which is located in the internal cavity.

[0028] Furthermore, the partition can be moved further upstream of the air inlet lip, thereby reducing the volume of the internal cavity without impacting the cooling performance of the internal and external partitions of the air inlet lip. In particular, the volume of the internal cavity can be halved. This facilitates the integration of the internal passage according to the invention.

[0029] Furthermore, since the volume of the internal cavity is reduced, the thermal power, and therefore the hot air flow rates required to heat this internal cavity, are also reduced. This allows the frost protection device to be resized accordingly. The invention may include one or more of the following features, taken individually or in combination:

[0030] - the plate has an omega-shaped cross-section,

[0031] - the plate has a cross-section comprising an intermediate wall and first and second flanges connected to the intermediate wall by inclined walls extending from the intermediate wall,

[0032] - the first and second footings are each fixed to the partition,

[0033] - the first and second connecting rods linking the first and second soles to the partition wall respectively,

[0034] - The thermal insulation layer is connected to both the partition and the panel, - The thermal insulation layer has an omega-shaped cross-section, - Hot air outlet holes are provided in the inner and / or outer wall.

[0035] - the partition is flat or curved,

[0036] - the blade is located in the internal passage.

[0037] Brief description of the figures

[0038] Other features and advantages will become apparent from the following description of non-limiting embodiments of the invention with reference to the accompanying drawings in which:

[0039] [Fig.1] Figure 1 is a longitudinal cross-sectional view of an example of a propulsion assembly to which the invention can be applied;

[0040] [Fig.2] Figure 2 is a longitudinal cross-sectional view of an example of an air inlet lip according to the invention;

[0041] [Fig. 3] Figure 3 is a cross-sectional diagram of a plate fitting the air inlet lip of Figure 2,

[0042] [Fig. 4] Figure 4 is a diagram of an example of an anti-icing device according to the invention and fitted to the air inlet lip of Figure 2; [Fig. 5] Figure 5 is a diagram of another example of an anti-icing device according to the invention and fitted to the air inlet lip of Figure 2.

[0043] [Fig. 6] Figure 6 is a longitudinal cross-sectional view of another example of an air inlet lip according to the invention,

[0044] [Fig. 7] Figure 7 is a longitudinal cross-sectional view of another example of an air inlet lip according to the invention,

[0045] [Fig. 8] Figure 8 is a longitudinal cross-sectional view of another example of an air inlet lip according to the invention,

[0046] [Fig. 9] Figure 9 is a cross-sectional view of an air inlet lip as shown in Figure 8.

[0047] [Fig.10] Figure 10 is a longitudinal cross-sectional view of an air inlet lip according to a variant of the example in Figure 8.

[0048] Detailed description of the invention

[0049] A propulsion assembly 1 is for example represented in figure 1.

[0050] The propulsion assembly 1 extends along a longitudinal axis X. A gas flow F flows into the turbomachine 1.

[0051] For the purposes of the present invention, the terms "upstream" and "downstream" are understood relative to the direction of flow of the gas flow F in the propulsion assembly 1 along the longitudinal axis X.

[0052] The terms "radial", "radially", "longitudinally", "axial", "axially", are understood in relation to the longitudinal axis X.

[0053] The terms "internal", "internally", "external", "externally", are understood in relation to the distance of the longitudinal axis X along a radial axis to the longitudinal axis X.

[0054] The propulsion unit 1 comprises a turbomachine 2 and a nacelle 3. The turbomachine 2 comprises, from upstream to downstream, a blower 4 and a gas generator 5. The gas generator may comprise, from upstream to downstream, a low-pressure compressor, a high-pressure compressor, at least one annular combustion chamber, a high-pressure turbine and a low-pressure turbine.

[0055] Each compressor comprises a compressor rotor, and each turbine comprises a turbine rotor. The compressor rotor of the low-pressure compressor is connected to the turbine rotor of the low-pressure turbine by a low-pressure shaft. Together, they form a low-pressure unit.

[0056] The compressor rotor of the high-pressure compressor is connected to the turbine rotor of the high-pressure turbine by a high-pressure shaft (not shown). They form a high-pressure unit.

[0057] The low pressure and high pressure shafts can be centered on the longitudinal X axis and are movable in rotation around the longitudinal X axis. The high pressure shaft is arranged coaxially around the low pressure shaft.

[0058] The blower 2 comprises a disk centered on the longitudinal axis X and blades 6 extending radially from the disk and regularly distributed around the longitudinal axis X. The disk and the blades 6 are movable in rotation around the longitudinal axis X.

[0059] The gas flow F passes through the blower 4 and splits into a primary air flow F1, which flows through an annular primary stream, and a secondary air flow F2, which flows through an annular secondary stream surrounding the primary stream. The primary air flow F1 passes through the gas generator and thus successively through the low-pressure and high-pressure compressors. The compressed primary air flow F1 then passes through the combustion chamber where it is mixed with fuel. The combustion gases then pass through the high-pressure and low-pressure turbines. The energy of the gases is transformed by the turbine rotor of the low-pressure turbine into mechanical energy, which drives the low-pressure shaft and, consequently, the low-pressure compressor.

[0060] The secondary airflow F2 passes through the secondary air stream and generates the majority of the thrust of the turbomachine 1. The nacelle 3 extends along and around the longitudinal axis X. It is located around the turbomachine 2. The nacelle 3 includes an air inlet lip 7.

[0061] The air inlet lip 7 is annular and extends around the longitudinal axis X. The air inlet lip 7 comprises an inner wall 8 and an outer wall 9.

[0062] The inner and outer walls 8, 9 are annular and are centered on the longitudinal axis X. The outer wall 9 is located coaxially around the inner wall 9. The inner and outer walls 8, 9 are connected together by a connecting wall 10. The connecting wall 10 forms a peripheral edge of the air inlet lip 7. The connecting wall 10 has a U-shaped cross-section.

[0063] The inner and outer walls 8, 9 define an internal cavity 11. The internal cavity 11 has a predetermined volume. The internal cavity 11 is closed. It can be partially opened by means of orifices as described below. The internal cavity 11 is bounded radially by the inner and outer walls 8, 9 and axially upstream by the connecting wall 10. The air inlet lip 7 further includes a partition 12 that connects the inner and outer walls 8, 9. The partition 12 is located downstream of the connecting wall 10. It closes the internal cavity 11.

[0064] Partition 12 has an advantageous thickness between 0.8 mm and 2 mm. Partition 12 preferably comprises a metallic material, in particular titanium or a titanium alloy.

[0065] According to the first example illustrated in Figure 2, partition 12 has a flat shape. According to other examples illustrated in Figures 5 and 6, partition 12 has a curved shape.

[0066] Partition 12 is annular and can be centered on the longitudinal axis X. Partition 12 can be sectorized and comprise a plurality of partition sectors.

[0067] The partition 12 extends radially between the inner and outer walls 8 and 9. As more clearly seen in Figure 2, the partition 12 extends radially between an outer end 12a and an opposite inner end 12b. The outer end 12a is connected to the outer wall 9, and the inner end 12b is connected to the inner wall 8.

[0068] The air inlet lip 7 is subject to a risk of frost and / or ice formation. In order to reduce or even eliminate this risk, the air inlet lip 7 includes an anti-icing device 13. The anti-icing device 13 is at least partially housed within the internal cavity 11.

[0069] The anti-icing device 13 includes an internal passage 14 for the circulation of hot air A1. The internal passage 14 is annular. The internal passage 14 is located in the internal cavity 11.

[0070] According to the invention, the internal passage 14 is delimited by the partition 12 and a plate 15.

[0071] Plate 15 is positioned opposite partition 12. Plate 15 is located in internal cavity 11.

[0072] Plate 15 is annular and can be centered on the longitudinal axis X. Plate 15 has an annular elongation axis that can be centered on the longitudinal axis X. Plate 15 can be sectored and thus comprise a plurality of plate 15 sectors.

[0073] Referring to Figure 3, the plate 15 has an omega shape in cross-section with respect to its elongation axis Y. Thus, the plate 15 comprises, according to this cross-section, an intermediate wall 16 and first and second flanges 17, 18 located on either side of the intermediate wall 16. The intermediate wall 16 and the first and second flanges 17, 18 extend respectively in a plane that is perpendicular to the elongation axis Y of the plate 15.

[0074] In one embodiment, the intermediate wall 16 is curved. It has a rounded apex 16a. The intermediate wall 16 has a concave shape. In another embodiment, the intermediate wall 16 has a flat shape and extends in a plane parallel to a plane in which the partition 12 extends. The first and second flanges 17, 18 have a flat shape. They extend parallel to the partition 12. The first and second flanges 17, 18 are located opposite the partition 12 and fixed to it. The intermediate wall 16 is connected to the first and second flanges 17, 18 by means of the first and second inclined walls 19, 20. The first and second inclined walls extend from the intermediate wall 16 to the first and second flanges 17, 18, respectively.The first and second inclined walls 18, 20 flare out from the intermediate wall 16 and towards the first and second footings 17, 18.

[0075] The plate 15 is connected to the partition 12. In particular, it is attached to and fixed to the partition 12. According to the example of the invention, the plate 15 is connected to the partition 12 via the first and second flanges 17, 18. The first and second flanges 17, 18 are fixed to the partition 12 by first and second connecting rods 21, 22. The first and second connecting rods 21, 22 extend perpendicularly to the partition 12 and to the first and second flanges 17, 18. The first and second connecting rods 21, 22 respectively connect the first and second flanges 17, 18 to the partition 12.

[0076] Plate 15 has an advantageous thickness between 0.8 mm and 2 mm.

[0077] Preferably, plate 15 comprises a material identical to the material of partition 12. Preferably, plate 15 comprises a metallic material. The metallic material is preferably titanium or a titanium alloy.

[0078] The internal passage 14 is thus surrounded or delimited by this plate 15 and by the partition 12. The internal passage 14 is therefore partially formed by the partition 12. Such a configuration of the internal passage 14 eliminates the need for a dedicated tube. Since the size of the internal cavity 11 is reduced, typically halved, the heat input required to heat this air cavity 11 is significantly reduced, and it is therefore possible to resize the anti-icing device 13, which can have a lower power output and provide a lower hot air flow rate A1.

[0079] The hot air A1 circulates in the internal passage 14 and heats the internal cavity 11 as it flows through the internal passage 14. This warms the internal and external walls 8, 9 of the air inlet lip 7 to reduce or even eliminate the risk of frost and / or ice formation.

[0080] Hot air A1 can be drawn from the turbomachine 2, for example from the compressors, particularly the high-pressure compressor. Hot air A1 then circulates through the internal cavity 11 and supplies it. The anti-icing device 13 can be of the "swirl" type (also known as an ejector type) or of the "piccolo" type.

[0081] According to a first example illustrated in Figure 2, in which the anti-icing device is of the "piccolo" type, the plate 15 has perforations (not visible). These perforations are preferably formed on the intermediate wall 16. The perforations allow the distribution of hot air A1 into the internal cavity 14.

[0082] According to a second example illustrated in figures 8, 9 and 10, in which the anti-icing device 13 is of the "ejector" type, the internal passage 14 is connected to a hot air sampling tube T A1 connected to the turbomachine 2. According to this example, the plate 15 has an open end 15a for distributing hot air A1 into the internal cavity 14.

[0083] According to an advantageous embodiment illustrated in Figure 5, the air inlet lip 7 may further comprise a thermal insulation blade 23. The blade 23 is annular and centered on the longitudinal axis X. It is located between the partition 12 and the plate 15. It is therefore situated within the internal passage 14.

[0084] The shape of the blade 23 is advantageously substantially identical to the shape of the plate 15. The blade 23 has, in cross-section with respect to its elongation axis, an omega shape. According to this cross-section, it comprises an intermediate wall 24 and first and second flanges 25, 26 located on either side of the intermediate wall 24. The intermediate wall 24 and the first and second flanges 25, 26 extend respectively in a plane that is perpendicular to the elongation axis of the blade 23.

[0085] In one embodiment, the intermediate wall 24 is curved. It has a rounded apex. The intermediate wall 24 has a concave shape. In another embodiment, the intermediate wall 24 has a flat shape and extends in a plane parallel to a plane in which the partition 12 extends.

[0086] The first and second flanges 25, 26 have a flat shape. They extend parallel to the partition 12. The first and second flanges 25, 26 are sandwiched between the first and second flanges 17, 18 of the plate 15 and the partition 12.

[0087] The intermediate wall 24 is connected to the first and second footings 25, 26, 18 via first and second inclined walls. The first and second inclined walls extend from the intermediate wall 24 to the first and second flanges 25, 26, respectively. The first and second inclined walls flare out from the intermediate wall 24 towards the first and second flanges 25, 26. The blade 23 is connected to both the partition 12 and the plate 15. According to the embodiment of the invention, the blade 23 is connected to the partition 12 and the plate 15 via the first and second connecting rods 21, 22. The first and second connecting rods 21, 22 thus connect the first and second flanges 17, 18, 25, 26 of the plate 15 and the blade 23 and the partition 12 to each other.

[0088] Blade 23 has an advantageous thickness between 0.8 mm and 2 mm.

[0089] Preferably, the blade 23 comprises a metallic material. The metallic material is, for example, Inconel. The blade 23 provides thermal insulation to the partition 12 when the air inlet lip 7 is subjected to high temperatures. This helps to limit the risk of thermal degradation of the partition 12.

[0090] According to an advantageous embodiment of the invention, the air inlet lip 7 may further include hot air outlet orifices 27, 28 A1. According to a first example illustrated in figure 6, the orifices 27 are provided or formed in the inner wall 8.

[0091] According to a second example illustrated in figure 7, the orifices 27, 28 are provided or formed in the inner wall 8 and in the outer wall 9. The orifices 27, 28 are advantageously regularly distributed around the longitudinal axis X. They are thus organized in the form of at least one annular row.

[0092] The orifices 27, 28 are through-holes and communicate fluidly with the internal cavity 11 and the outside of the air inlet lip 7. The orifices 27, 28 each have an axis which extends transversely with respect to the longitudinal axis X. Preferably, the axis of each orifice 27, 28 is inclined with respect to a radial axis in particular by an angle between 15° and 90° as measured in a plane passing through the longitudinal axis.

[0093] Each orifice 27, 28 has, for example, a diameter between 0.5 mm and 2 mm, preferably between 1 mm and 2 mm.

[0094] The orifices 27, 28 are located upstream of the partition 12. In particular, they are located axially between the connecting wall 10 and the partition 12. The hot air A1 from the internal cavity 11 is thus evacuated through the orifices 27, 28 outside the air inlet lip 7. The evacuated hot air A1 forms a film 29 of hot air on the surface of the internal and / or external walls 8, 9 which also helps to limit the risk of frost and / or ice formation.

[0095] The air inlet lip 7 may further include acoustic insulation panels (not shown). Each acoustic insulation panel may be attached to the inner wall 8 of the air inlet lip 7. Each acoustic insulation panel may be located downstream of the partition 12. Each acoustic insulation panel may be multilayered. Each acoustic insulation panel comprises, for example, an inner skin, an outer skin, and a core sandwiched between the inner and outer skins. The outer skin may be connected to the inner wall 8 of the air inlet lip 7. The core may have honeycomb-shaped cells. The inner and outer skins may comprise a composite material. The composite material is, for example, an organic matrix composite, known by the acronym CMO. The composite material comprises an organic matrix and fibers embedded within the matrix.The organic matrix includes, for example, an epoxy polymer and the fibers include, for example, carbon fibers.

[0096] Preferably, the number, size, shape and orientation of the orifices 27, 28 are determined to generate the hot air film 29 A1 according to a compromise between the effectiveness of the frost protection properties of this film 29 and the thermal resistance of the inner and outer skins of each composite panel.

Claims

DEMANDS 1. Air inlet lip (7) for an aircraft nacelle (3), the air inlet lip (7) being annular around a longitudinal axis (X) and comprising: - an annular internal wall (8) centered on the longitudinal axis (X), - an annular outer wall (9) extending coaxially around the inner wall (8), - an internal annular cavity (11) delimited radially by the internal and external walls (8, 9), - an annular partition (12) radially connecting the internal and external walls (8, 9) and axially closing the internal cavity (11), and - an anti-icing device (13) housed at least partly in the internal cavity (11) and comprising an internal annular passage (14) for the circulation of hot air (A1), characterized in that the internal passage (14) is delimited by the partition (12) and an annular plate (15) disposed in the internal cavity (11) opposite the partition (12) and connected to the partition (12), the air inlet lip (7) further comprising a thermal insulation blade (23) located between the partition (12) and the plate (15).

2. Air inlet lip according to the preceding claim, characterized in that the plate (15) has an omega-shaped cross-section.

3. Air inlet lip according to the preceding claim, characterized in that the plate (15) has a cross-section comprising an intermediate wall (16) and first and second flanges (17, 18) connected to the intermediate wall (16) by inclined walls (19, 20) extending from the intermediate wall (16).

4. Air inlet lip according to the preceding claim, characterized in that the first and second flanges (17, 18) are each fixed to the partition (12).

5. Air inlet lip according to the preceding claim, characterized in that it comprises first and second connecting rods (21, 22) respectively connecting the first and second soles (17, 18) to the partition (12).

6. Air inlet lip according to any one of the preceding claims, characterized in that the thermal insulation blade (23) is connected to both the partition (12) and the plate (15).

7. Air inlet lip according to any one of the preceding claims, characterized in that the thermal insulation blade (23) has an omega-shaped cross-section.

8. Air inlet lip according to any one of the preceding claims, characterized in that it comprises hot air outlet orifices (27, 28) (A1) provided in the inner wall (8) and / or in the outer wall (9).

9. Air inlet lip according to any one of the preceding claims, characterized in that the partition (12) is flat or curved.

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