Inlet cone for an aircraft turbomachine

Abstract

An inlet cone for an aircraft turbomachine, the inlet cone having at least one first portion made of a first material, referred to as a rigid material, and at least one second portion made of a second material, the hardness of which is less than that of the first material and which is referred to as a flexible material, the second portions being configured to elastically deform in a radial direction with respect to the axis when the cone is driven in rotation.

Description

Technical Field

[0001] The field of this invention is the field of turbines, and in particular the field of gas turbine engines (e.g., but not limited to turbojet engines or aircraft turboprop engines).

[0002] More specifically, the present invention relates to an air inlet cone for a turbine. Background Technology

[0003] Prior art includes, in particular, the document US-A1-2016 / 122034.

[0004] In the prior art, turbines extending along a longitudinal axis are known, which include, from upstream to downstream, a fan, one or more compressor stages (e.g., a low-pressure compressor and a high-pressure compressor), a combustion chamber, one or more turbine stages (e.g., a high-pressure turbine and a low-pressure turbine), and a gas discharge nozzle.

[0005] Typically, such a turbine also includes an air inlet cone upstream, which is mounted on the fan, for example, via a generally annular upstream housing, which itself is connected to the turbine's low-pressure compressor shaft. The connection between the inlet cone and the upstream housing is usually made by a bolted assembly. The downstream end of the housing is flush with the platform of the fan blades and is located in the forward aerodynamic continuum of the fan blades.

[0006] This inlet cone includes an upstream end with a conical or elliptical shape centered on the rotation axis of the inlet cone, which also corresponds to the longitudinal axis of the fan and the entire turbine.

[0007] It is known, particularly when the turbine is at a steady speed, that the inlet cone is a point on the turbine that favors ice buildup, such as... Figure 2a As shown. Therefore, especially during the acceleration phase of the turbine, the ice forming on the inlet cone may reach a large size before breaking into large ice fragments, such as... Figure 2b and Figure 2c As shown. When these large ice fragments eventually break off from the cone, they pose a risk of damaging the fan blades that the ice fragments impact or damaging components located downstream of the fan blades.

[0008] Accumulated ice may also gather unevenly on the inlet cone, causing unwanted vibrations in the turbine.

[0009] To overcome this problem, it has been suggested to install a de-icing system, the purpose of which is to ensure that the ice accumulating on the tip of the cone is removed before it reaches a critical size. However, this type of system is expensive in terms of mass and overall size, and is particularly difficult to install due to the rotating nature of the inlet cone it is equipped with.

[0010] It is also recommended that, Figure 3 The inlet cone 10' shown is manufactured as follows: it has an upstream tip 12' made of a flexible material and a downstream body 14' made of a rigid material. During operation, ice buildup, particularly at the junction where the tip and body meet, is reduced to facilitate ice separation. However, when the turbine is in flight operation, this method of separating the ice layer by reducing it and allowing cracks to propagate along the layer may be slower than intended. The larger the ice layer, the slower and more difficult it is to form cracks within it. Furthermore, particularly at low temperatures (i.e., between -30°C and 15°C), the adhesion between the ice and the cone is greater than the force required to separate the ice by centrifugal force, making it insufficient to directly create cracks between the portion of the cone made of flexible material and the accumulated ice. Therefore, this solution is insufficient to rapidly separate the ice layer formed on the inlet cone into multiple small fragments without damaging components downstream of the turbine cone.

[0011] In this context, it is of interest to propose a solution that enables the overcoming of the shortcomings of the prior art, particularly by introducing a new geometry for the air inlet cone, which is more conducive to the controlled breaking of ice during operation. Summary of the Invention

[0012] Therefore, the present invention proposes an inlet cone for an aircraft turbine, the inlet cone being configured to be driven to rotate about an axis X, and the inlet cone comprising a conical or elliptical body on which ice can form, the body having at least one first portion made of a first material and at least one second portion made of a second material, the first material being referred to as a rigid material, the second material having a hardness less than that of the first material and being referred to as a flexible material.

[0013] According to the invention, the first part is integral and formed of a plurality of axial segments connected to each other by partitions extending in a longitudinal direction relative to the axis X, the segments and the partitions defining a receiving portion between the segments and the partitions, and the body includes a plurality of second portions located in the receiving portion, the second portions being configured to elastically deform in a radial direction relative to the axis X when the cone is driven to rotate.

[0014] This design of the invention makes it easier to reduce the size of ice accumulating on the turbine inlet cone during operation, thereby limiting the impact of ice deaccumulation on the turbine.

[0015] To achieve this, the cone comprises multiple second sections and a single first section. The second sections are made of a flexible or elastically deformable material (e.g., an elastomer) so that each second section can deform and move radially (relative to the axis X) as the cone rotates, and also continues to function under varying external temperatures (e.g., low temperatures between -30°C and 15°C). This helps to break up ice build-ups that form on the outer surface of the cone. The first section is made of a rigid material (e.g., aluminum) to form a single, stable base support for holding the second sections in place.

[0016] According to the configuration of the invention, the second part is separated from the first part by a partition and / or an axial segment. This has the advantage of having a body with an alternating pattern between the rigid material of the first part forming the cone and the flexible material of the second part.

[0017] During operation (on the ground or while the turbine is in flight) and as ice accumulates on the cone, a deviation in deformation (or displacement) of the second section relative to the first section under centrifugal force was observed. This deviation generates stress in the ice at the interface between the rigid and flexible materials. This causes the ice to break into multiple fragments at each interface of the alternating patterns of the cone's body. In this way, the size of the separated ice fragments is calibrated and is acceptable for being ejected onto components downstream of the cone (e.g., fan blades) without damaging them.

[0018] Furthermore, the separated ice fragments are released regularly in multiple stages. For example, during the turbine's acceleration phase, ice located at the highest radius of the cone separates first, compared to ice located at the tip of the cone.

[0019] Therefore, the advantages of this invention are that it provides very high reliability, low cost, and small overall size based on a simple design.

[0020] The inlet cone for an aircraft turbine according to the invention may include one or more of the following features, either independently or in combination:

[0021] - The body includes an end forming a tip, the tip being made of the second material;

[0022] - Each of the receptacles has a generally arcuate shape around the axis, and the second part is configured to completely fill these receptacles;

[0023] - The Young's modulus of each of the second parts is between 1 MPa and 10 MPa, preferably between 1 MPa and 4 MPa;

[0024] - The maximum thickness of each second part in the second part is between 2 mm and 10 mm, and the thickness is measured in the longitudinal direction relative to the axis X;

[0025] - Each of the second parts includes an outer surface with a maximum radius between 20 mm and 100 mm (preferably between 40 mm and 80 mm), which is measured relative to the axis X.

[0026] - The density of each of the second parts is between 500 kg / m³ 3 Up to 1500 kg / m 3 Between, preferably 1200 kg / m 3 ;

[0027] - Each axial segment is an angular sector between 10° and 90°;

[0028] - Each flexible part is made of elastomer, silicone, rubber or polytetrafluoroethylene (PTFE);

[0029] - The rigid part is made of composite material or metal material, such as aluminum.

[0030] The present invention also relates to an aircraft turbine comprising an inlet cone according to the invention.

[0031] The present invention also relates to a method for using a turbine according to the invention, wherein the cone rotates at a first speed V1 or a second speed V2, the first speed being at least greater than 5000 rpm and the second speed being lower than the first speed V1.

[0032] According to the invention, when the cone rotates at a first speed V1, the flexible portion moves radially relative to the axis X and is configured to break up ice deposited on the cone, and when the cone rotates at a second speed or is at a standstill, the flexible portion is fixed.

[0033] The radial displacement of the flexible portion can be greater than 0.02 mm, and preferably between 0.02 mm and 0.2 mm.

[0034] The present invention also relates to an aircraft comprising a turbine according to the invention. Attached Figure Description

[0035] The invention will be better understood through the following description, which is by way of non-limiting example and with reference to the accompanying drawings, and other details, features, and advantages of the invention will become clearer, as illustrated in the drawings:

[0036] [ Figure 1 ] Figure 1 This is a schematic half-view of the axial cross-section of an aircraft turbine according to an embodiment of the present invention.

[0037] [ Figure 2a ] Figure 2a A schematic half-view of an axial cross-section of ice buildup on an inlet cone in the prior art is shown.

[0038] [ Figure 2b ] Figure 2b The illustration shows the source Figure 2a A half-view of the axial cross-section of the broken ice at the entrance cone.

[0039] [ Figure 2c ] Figure 2c The illustration shows the source Figure 2a A half-view of the axial cross-section of randomly large fragments of ice separated from the entrance cone.

[0040] [ Figure 3 ] Figure 3 This is a schematic front perspective view of the entry cone section in the prior art.

[0041] [ Figure 4 ] Figure 4 This is a schematic front perspective view of the inlet cone according to a first embodiment of the present invention;

[0042] [ Figure 5a ] Figure 5a schematically shown Figure 4 A half-view of the axial cross-section of ice accumulation on the inlet cone.

[0043] [ Figure 5b ] Figure 5b The illustration shows the source Figure 5a A half-view of the axial cross-section of the broken ice at the entrance cone.

[0044] [ Figure 5c ] Figure 5c The illustration shows the source Figure 4 A half-view of the axial cross-section of the inlet cone containing controlled and reduced-sized ice fragments.

[0045] [ Figure 6 ] Figure 6 A graph showing the radial displacement of the second portion of the cone of the present invention as a function of the rotational speed of the cone is shown. Detailed Implementation

[0046] As is customary in this application, the terms "inner" and "outer," as well as "internal" and "external," are radially defined relative to the longitudinal axis X of the turbine's aircraft engine. For example, a cylindrical portion extending along axis X includes an inner surface and an outer surface, the inner surface facing the engine's axis and the outer surface opposite the inner surface of the cylindrical portion. "Axial" or "axially" refers to any direction parallel to axis X, and "lateral" or "transverse" refers to any direction perpendicular to axis X. Similarly, the terms "upstream" and "downstream" are defined relative to the direction of airflow within the turbine.

[0047] Figure 1 A two-flow turbine 1 specifically designed for use in aircraft is shown. However, this is not limiting; the turbine can be of another type, such as a turboprop engine.

[0048] Turbine 1 extends along a longitudinal axis X and includes, from upstream to downstream, a fan 2, one or more compressor stages (e.g., low-pressure compressor 3 and high-pressure compressor 4), a combustion chamber 5, one or more turbine stages (e.g., high-pressure turbine 6 and low-pressure turbine 7), and a gas exhaust nozzle 8 in the gas flow direction. Fan 2, low-pressure compressor 3, and low-pressure turbine 7 are connected to a low-pressure shaft extending along the longitudinal axis. High-pressure compressor 4 and high-pressure turbine 6 are connected to a high-pressure shaft arranged around the low-pressure shaft. Low-pressure turbine 7 drives the low-pressure shaft to rotate, while high-pressure turbine 6 drives the high-pressure shaft to rotate.

[0049] The turbine 1 also includes air inlet cones 10 and 10' upstream of the fan 2, which are preferably mounted to the fan 2 by means of a housing (not shown) via bolt-type attachments. The housing is located downstream of the inlet cones 10 and 10' and is also connected to the low-pressure shaft.

[0050] The inlet cones 10 and 10' are connected to the rotor together with the housing; in other words, they are connected to the rotating components of the turbine 1. Therefore, the inlet cones 10 and 10' rotate about the longitudinal axis X.

[0051] Figure 2a , Figure 2b , Figure 2c as well as Figure 3 The inlet cone 10' of the prior art described above is shown in the background art of this application.

[0052] Figure 4 An inlet cone 10 according to the invention is shown. The cone 10 is configured to be driven to rotate about axis X on the one hand, and to break up ice accumulated on the cone 10 into multiple fragments of calibrated size on the other hand, so as not to damage the blades of the fan 2.

[0053] For this purpose, the cone portion 10 includes a tapered body extending around a rotation axis. This rotation axis of the cone portion 10 corresponds to the turbine's axis X.

[0054] The main body of the cone 10 includes a first part 20 made of a first material called a rigid material.

[0055] The first part 20 is a single integral piece. The first part 20 is formed by a plurality of axial segments 22 connected together by a partition 24. The partition 24 extends in a longitudinal direction relative to the axis X. The plurality of axial segments 22 may be formed by at least one upstream segment 22a and one downstream segment 22b. The diameter of the upstream segment 22a is smaller than the diameter of the downstream segment 22b. The plurality of segments 22 may also include one or more intermediate segments 22c inserted between the upstream segment 22a and the downstream segment 22b. The diameter of each intermediate segment 22c is smaller than the diameter of the downstream segment 22b and larger than the diameter of the upstream segment 22a.

[0056] exist Figure 4 In the example shown, each segment 22 includes as many sectors as the partitions 26 to which the segment is connected. Each sector of the segment extends between two adjacent partitions.

[0057] Multiple axial segments 22 and partitions 24 define receiving portions 26 between them. Each receiving portion 26 may be an opening. In this example, each receiving portion 26 may have a generally arcuate shape relative to the axis X.

[0058] The first material can be a metallic material (such as aluminum) or a composite material.

[0059] The main body of the cone 10 also includes a plurality of second portions 30, each made of a second material called a flexible material. The hardness of the second material is lower than that of the first material. For example, the hardness of the material is defined by Young's modulus.

[0060] The Young's modulus of each second part 30 can be between 1 MPa and 10 MPa. Preferably, the Young's modulus of the second part 30 is between 1 MPa and 4 MPa.

[0061] The density of each of the second parts (30) can be between 500 kg / m³. 3 Up to 1500 kg / m 3 Between. Preferably, the density is 1200 kg / m³. 3 .

[0062] The second material can be an elastomer, silicone resin, rubber, or polytetrafluoroethylene (PTFE).

[0063] The maximum radius of the cone 10 can be 50cm.

[0064] exist Figure 4 In the example shown, each second section 30 is an angular sector. Each angular sector can be between 5° and 345°. Preferably, the angular sector can be between 5° and 180°. Even more preferably, the angular sector can be between 10° and 90°.

[0065] The second portion 30 is located within the receiving portion 26 of the first portion 20. In this example, the second portion 30 is spaced apart and separated from each other by at least one of the segments 22 and / or at least one of the partitions 26. This results in the body of the cone portion 10 having an alternating pattern, particularly between the segments 22 of the first portion 20 and the second portion 30 (in the longitudinal direction relative to the axis X).

[0066] Each second portion 30 has a shape complementary to the shape of the corresponding receiving portion 26. In this way, the second portion 30 is configured to completely fill the receiving portion.

[0067] The maximum thickness E of each second portion in the second portion 30 can be from 2 mm to 10 mm, preferably 4 mm. The thickness E is measured in the longitudinal direction relative to the axis X. Figure 5a The radial direction is approximately perpendicular to the axis X.

[0068] Each of the second portions 30 includes an outer surface 32, the maximum radius r of which can be from 20 mm to 100 mm, preferably 40 mm. The radius r is measured in the radial direction relative to the axis X. Figure 5a ).

[0069] The body of the cone 10 may include an end forming a tip 12. In this example, the tip 12 is made of a second material. Alternatively, the tip 12 is made of a first material, wherein the tip 12 and the first portion 20 are integral.

[0070] The alternation pattern between the first and second materials according to the invention can be applied to any type of air inlet cone of a turbine, while allowing adjustment of the tip angle and length according to the size of the inlet cone. Furthermore, the hardness of the second material is a parameter that varies depending on the size of the inlet cone, the angle of attack, and the rotational speed.

[0071] According to other variations not shown, the receiving portion 26 can be a spiral groove and the second portion 30 can have a spiral configuration, or the longitudinal groove and the second portion 30 can have a straight shape. These variations also enable the formation of other patterns, such that the first material and the second material alternate on the body of the cone.

[0072] Typically, when the cone 10 is driven to rotate, the second part 30 is able to elastically deform in the radial direction. This allows stress to be generated in the ice formed at the interface between the rigid and flexible materials, thereby breaking the ice into multiple fragments with a calibration size acceptable for the impact on the fan blades 2.

[0073] Reference Figures 5a to 5c This application describes ice breaking achieved by a specific configuration of the cone 10 of the present invention.

[0074] When the turbine is running at a steady state (i.e., at 3000 rpm or lower), such as Figure 2a As shown, ice G forms on the outer surface of the inlet cone 10. When the cone 10 is rotated at a second speed V2 by the turbine, there is no relative movement between the rigid and flexible materials. Therefore, the second part 30 is fixed.

[0075] When the cone 10 is rotated at a first speed V1 by the turbine, as Figure 5b As shown, the second part 30, under the action of centrifugal force, deviates from the first part 20 in the radial direction relative to the axis X by deformation D (or displacement). This deviation generates cracks, which cause the ice G at the interface between the rigid and flexible materials to break apart. This allows the ice G to break into multiple fragments.

[0076] Figure 5c The separation of ice fragments is shown, with the size of the ice fragments reduced so as not to damage the downstream component of the cone 10.

[0077] The first speed V1 can be at least 5000 rpm, and the second speed V2 can be less than 5000 rpm.

[0078] The deformation deviation D (or radial displacement) of the second part is greater than 0.02 mm. Preferably, the deviation is between 0.02 mm and 0.20 mm.

[0079] The dimensions (shape, thickness, size, hardness, etc.) of the receiving portion 26 in the first part 20 and the second part 30, as well as the position on the body of the cone 10, can vary depending on the desired size of the ice fragments to be broken and the type of the inlet cone.

[0080] When the cone 10 rotates at a second speed V2, the turbine can be accelerated to achieve the desired radial displacement of the second part and to break up the ice.

[0081] Advantageously, the radial displacement D of the second portion 30 of the cone 10 is proportional to at least one of the following dimensional parameters:

[0082] -The square of the rotational speed of the cone 10,

[0083] -The square of the thickness of the second part, 30.

[0084] - The hardness of the second material, and

[0085] - Part 2, 30, distance from axis X.

[0086] Therefore, at least one of the above dimensional parameters is changed to obtain a radial displacement of at least 0.02 mm on each of the second portions 30 and to cause ice to break with a maximum radial thickness of 15 mm on the cone 10, as summarized by way of example in the table below (Table 1).

[0087] [Table 1]

[0088]

[0089]

[0090] By way of example, the radial displacement of the second portion 30 of the cone 10 of the present invention is measured according to the speed of the turbine.

[0091] Therefore, the cone 10, with a maximum radius of 40 mm, includes a first part 20 made of metal (e.g., aluminum) and a second part 30 made of an elastomer with a Shore hardness A of 50 (at a temperature of 23°C). The radial displacement of the second part is measured under centrifugal force and based on the presence or absence of ice at 5000 rpm and 7500 rpm. For example, the radial thickness of ice formed on the cone is approximately 10 mm.

[0092] These measurements of the radial displacement of Part 2, 30 are summarized in the table below (Table 2).

[0093] [Table 2]

[0094]

[0095]

[0096] By way of examples Figure 6 The effect of radial displacement of the second portion 30 of the cone 10 of the present invention on the breaking of ice accumulated on the cone 10 (particularly at the interface between rigid and flexible materials) was determined to vary with different rotational speeds of the cone 10 (and therefore the turbine).

[0097] To achieve this, the cone 10 includes a first portion 20 made of metal (e.g., aluminum) and a second portion 30 made of an elastomer. The elastomer has a Shore A hardness of 50 (at 23°C) and a density of 1200 kg / m³. 3The second part 30 is 4 mm thick. The second part 30, which is the outer surface of the main body of the cone with a larger diameter, has a radius of 40 mm.

[0098] Zero speed corresponds to the stationary cone, steady speed corresponds to approximately 3,000 rpm, and maximum speed (corresponding to the acceleration phase) is approximately 7,500 rpm.

[0099] exist Figure 6 In this region, region Z1 corresponds to the radial displacement of the second part of the cone, where the breaking and separation of ice fragments with reduced and acceptable sizes can be observed. This region Z1 extends between 0.02 mm and 0.06 mm. Therefore, starting from a radial displacement of 0.02 mm, significant ice fragmentation is observed at the interface between the rigid and flexible materials.

[0100] exist Figure 6 In the region Z2, which corresponds to the minimum displacement or no radial displacement of the second part of the cone, no ice fragmentation or separation was observed.

Claims

1. An inlet cone (10) for an aircraft turbine (1), the inlet cone (10) being configured to be driven to rotate about an axis (X), and the inlet cone comprising a conical or elliptical body on which ice can form, the body having at least one first portion (20) made of a first material and at least one second portion (30) made of a second material, the first material being referred to as a rigid material, the second material having a hardness less than that of the first material, and the second material being referred to as a flexible material. Its features are, The first part (20) is integral and is formed of a plurality of axial segments (22) connected together by a partition (24) extending in the longitudinal direction relative to the axis (X), the axial segments (22) and the partition (24) defining a receiving portion (26) between the axial segments and the partition, and the body includes a plurality of second parts (30) located in the receiving portion (26), the second parts (30) being configured to elastically deform in the radial direction relative to the axis (X) when the inlet cone (10) is driven to rotate.

2. The inlet cone according to claim 1, characterized in that, The body includes an end forming a tip (12), the tip being made of the second material.

3. The inlet cone according to claim 1 or 2, characterized in that, Each of the receptacles (26) has a generally arcuate shape around the axis (X), and the second portion (30) is configured to completely fill these receptacles (26).

4. The inlet cone according to claim 1 or 2, characterized in that, The Young's modulus of each of the second parts (30) is between 1 MPa and 10 MPa.

5. The inlet cone according to claim 1 or 2, characterized in that, The maximum thickness (E) of each of the second portions (30) is 4 mm, and the maximum thickness (E) is measured in the longitudinal direction relative to the axis (X).

6. The inlet cone according to claim 1 or 2, characterized in that, Each of the second portions (30) includes an outer surface with a maximum radius (r) of 40 mm, which is measured relative to the axis (X).

7. The inlet cone according to claim 1 or 2, characterized in that, The density of each of the second portions (30) is between 500 kg / m³. 3 Up to 1500 kg / m 3 between.

8. The inlet cone according to claim 1 or 2, characterized in that, Each axial segment (22) is an angular sector between 10° and 90°.

9. The inlet cone according to claim 1 or 2, characterized in that, Each second part (30) is made of one of an elastomer, silicone resin or polytetrafluoroethylene (PTFE).

10. The inlet cone according to claim 1 or 2, characterized in that, The first part (20) is made of composite material or metal material.

11. The inlet cone according to claim 4, characterized in that, The Young's modulus of each of the second parts (30) is between 1 MPa and 4 MPa.

12. The inlet cone according to claim 7, characterized in that, The density of each of the second portions (30) is 1200 kg / m³. 3 .

13. The inlet cone according to claim 10, characterized in that, The first part (20) is made of aluminum.

14. The inlet cone according to claim 9, characterized in that, Each second part (30) is made of rubber.

15. An aircraft turbine (1) comprising an inlet cone (10) according to any one of claims 1 to 14.

16. A method for using an aircraft turbine (1) according to claim 15, characterized in that, The inlet cone (10) rotates at a first speed (V1) or a second speed (V2), the first speed being at least greater than 5000 rpm and the second speed being lower than the first speed (V1), and: - When the inlet cone (10) rotates at the first speed (V1), the second portion (30) moves radially relative to the axis (X) and is configured to break up the ice (G) deposited on the inlet cone (10), and - When the inlet cone (10) rotates at the second speed (V2) or is at a stop rotating, the second part (30) is fixed.

17. The method according to claim 16, characterized in that, The radial displacement of the second part is greater than 0.02 mm.

18. The method according to claim 17, characterized in that, The radial displacement of the second part is between 0.02 mm and 0.20 mm.

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