Tail nozzle, aeroengine and aircraft

Abstract

The present invention discloses a tail nozzle, an aero-engine and an aircraft. The tail nozzle includes a plurality of segmented parts, and the segmented parts surround the exhaust port of the tail nozzle. It is characterized in that a shape memory alloy mesh is formed on the outer side of the segmented parts. The shape memory alloy mesh includes shape memory alloy wires. Among them, the shape memory alloy mesh extends circumferentially to cover each of the segmented parts, and the length of the shape memory alloy mesh changes at the phase transition temperature to drive the segmented parts and change the size of the exhaust port of the tail nozzle. By using shape memory alloy as the actuating mechanism, the nozzle area of the tail nozzle is changed at different temperatures, thereby effectively avoiding the problem of noise without adding too much weight and complex mechanisms.

Description

Technical Field

[0001] The present invention relates to a tail nozzle, an aeroengine, and an aircraft. Background Art

[0002] When the tail nozzle of an aeroengine is working, it has different working states. By changing the size of the outlet of the tail nozzle, the working state of the engine can be changed, enabling the engine to obtain good performance in various working states. However, the tail nozzle with an adjustable nozzle is usually a mechanical structure, which is complex in structure and heavy in weight, and the mechanical transmission components work unreliably at high temperatures. Therefore, a non-adjustable convergent tail nozzle is adopted for civil turbofan engines.

[0003] At present, large bypass ratio turbofan engines usually adopt a non-adjustable convergent tail nozzle, also known as a subsonic nozzle with a fixed nozzle, including a serrated tail nozzle with a noise reduction function. Its structure is the simplest and the weight is the lightest. Almost all civil turbofan engines such as CFM56, PW4000, RB211, and GE90 adopt this kind of tail nozzle. Although when the available pressure ratio of the nozzle is greater than the critical pressure ratio (1.85), the gas cannot be fully expanded in the convergent tail nozzle, but in the case of a low flight speed (Ma≤1.5), the energy loss of the gas due to incomplete expansion is small. Therefore, it is appropriate to adopt this simple convergent tail nozzle.

[0004] However, in addition to the energy loss caused by incomplete expansion of the gas (resulting in a decrease in engine efficiency), with the increasing requirements for the environmental indicators of aeroengines, the noise problem caused by different jet velocities at different engine operating points has become increasingly prominent. Although a serrated noise reduction tail nozzle has been designed, the noise problem still exists at non-operating points of the engine, such as maximum climb. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defect that in the prior art, when an aeroengine ensures a simple structure and a light weight, it is impossible to avoid a large noise at different working states, and to provide a tail nozzle, an aeroengine, and an aircraft.

[0006] The present invention solves the above technical problem through the following technical solutions:

[0007] A tail nozzle for an aeroengine, comprising a plurality of segmented parts, the segmented parts surrounding to form an exhaust port of the tail nozzle. The feature is that a shape memory alloy mesh is formed on the outer side of the segmented parts. The shape memory alloy mesh includes shape memory alloy wires. Among them, the shape memory alloy mesh extends circumferentially to cover each of the segmented parts, and the length of the shape memory alloy mesh changes at the phase transition temperature to drive the segmented parts and change the size of the exhaust port of the tail nozzle.

[0008] Using shape memory alloy as the actuating mechanism to control the tail nozzle area can effectively avoid the noise problem without adding too much weight and complex mechanism. The shape memory alloy mesh can match the corresponding working state by setting the phase change temperature. When the exhaust of the tail nozzle reaches the phase change temperature, it will deform, so that the exhaust port of the tail nozzle reaches the preset size, effectively reducing noise.

[0009] At the same time, the shape memory alloy mesh can cover more positions of the slice part in a lighter manner, thereby reducing the use of materials while ensuring the deformation amount of the slice part.

[0010] Preferably, the cross-sectional shape of the shape memory alloy wire includes one or a combination of circular, rectangular, elliptical, triangular, and polygonal shapes.

[0011] Preferably, the shape memory alloy wire is in a straight line shape, a segmented shape, a curved shape, or a combination of multiple shapes.

[0012] Preferably, at least a portion of the shape memory alloy wires extend to the edge of each of the slice portions, and at least a portion of the shape memory alloy wires extending to the edge of the slice portions are cross-connected to each other.

[0013] Preferably, the shape of the slice portion is a sawtooth shape, an arc shape, a trapezoidal shape, or a combination of more.

[0014] Preferably, the shape memory alloy wire is directly coated on the segment portion by means of additive manufacturing, or the shape memory alloy wire is fixedly connected to the segment portion by being separately formed.

[0015] Preferably, the outer surface of each of the slice portions is formed into a sunken receiving groove by removing material, wherein the shape memory alloy wire is connected or coated in the receiving groove.

[0016] Preferably, the separately formed shape memory alloy wire is formed by one or more of casting, forging and machining.

[0017] Preferably, the shape memory alloy wire comprises at least two deformation segments with different phase transition temperatures, and each deformation segment expands the segment portion to different positions at at least two different temperatures, so that the exhaust port of the tail nozzle is changed into at least two different sizes.

[0018] Preferably, the shape memory alloy mesh includes three deformation segments with different phase transformation temperatures along the axial direction. Each deformation segment deforms the segmented part to different positions at three different temperatures, so that the exhaust port of the tail nozzle is changed into three different sizes. Thus, for the three states of the engine at idle, climb, and cruise, the tail nozzle has different exhaust temperatures at these three states. Through the contraction or elongation of the shape memory alloy wire at different temperatures, the deployment or closing of the tail nozzle is realized.

[0019] Preferably, the deformation segments with different phase transformation temperatures are processed from the same kind of shape memory alloy by using different additive manufacturing process parameters.

[0020] Preferably, the additive manufacturing process parameters are one or more of laser power, scanning rate, and scanning spacing, and / or the shape memory alloy is a nickel-titanium alloy.

[0021] Preferably, between the deformation segments with different phase transformation temperatures are sequentially scanned by laser along the extending direction of the shape memory alloy wire, and the material crystal phases between adjacent deformation segments with different phase transformation temperatures transition smoothly. Since it is made of the same kind of shape memory alloy, the deformation segments of the shape memory alloy wire still form an integral body. And through laser scanning, when scanning a deformation segment, the adjacent deformation segments will also be heated, making the crystal phases between the deformation segments change slowly. Therefore, stress concentration will not occur at the junction between the deformation segments, ensuring the strength of the shape memory alloy wire during repeated deformation.

[0022] Preferably, the junction between the deformation segments with different phase transformation temperatures is the intersection point of the shape memory alloy wire.

[0023] An aeroengine, characterized in that the aeroengine includes the tail nozzle, wherein the tail nozzle is the core nozzle and / or the bypass nozzle of the aeroengine.

[0024] An aircraft, characterized in that the aircraft includes one or more of the aeroengines.

[0025] The positive and progressive effects of the present invention are as follows: Using a shape memory alloy as an actuating mechanism to change and control the nozzle area of the tail nozzle at different temperatures, thereby effectively avoiding the problem of noise without adding too much weight and complex mechanisms. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic structural diagram of the aeroengine according to a preferred embodiment of the present invention.

[0027] Figure 2 It is a schematic structural diagram of the tail nozzle according to a preferred embodiment of the present invention.

[0028] Figure 3 Schematic structural diagram of the segmented part of a preferred embodiment of the present invention.

[0029] Figure 4 is Figure 3 Schematic cross-sectional structure diagram in the A-A direction in

[0030] Figure 5 Schematic deformation diagram of the segmented part of a preferred embodiment of the present invention at the first phase change temperature.

[0031] Figure 6 Schematic deformation diagram of the segmented part of a preferred embodiment of the present invention at the second phase change temperature.

[0032] Figure 7 Schematic deformation diagram of the segmented part of a preferred embodiment of the present invention at the third phase change temperature.

[0033] Figure 8 Schematic deformation diagram of the segmented part of a preferred embodiment of the present invention at the fourth phase change temperature. Detailed implementation manners

[0034] The present invention will be further described below by way of embodiments, but the present invention is not limited to the scope of the described embodiments.

[0035] As Figure 1 shown, this embodiment discloses an aeroengine, which is mainly used for an aircraft, and the aircraft may include one or more aeroengines of this embodiment. Among them, as Figure 1 shown, this embodiment exemplarily shows a specific structure of an aeroengine, including an engine nacelle 1, an outer duct nozzle 2, an inner duct nozzle 3, an inner duct 4, and an outer duct 5. Among them, the tail nozzle 6 of this embodiment can be used for the inner duct nozzle 3 and / or the outer duct nozzle 2 of the aeroengine. In aeroengines with other structures, the tail nozzle 6 can also be applied to the corresponding nozzle structures.

[0036] As Figures 2 - 3 shown, the tail nozzle 6 of this embodiment includes a plurality of segmented parts 61. The segmented parts 61 surround the exhaust port 60 of the tail nozzle 6. A shape memory alloy mesh 62 is formed on the outer side of the segmented parts 61. The shape memory alloy mesh 62 includes shape memory alloy wires 621. Among them, the shape memory alloy mesh 62 extends circumferentially to cover each segmented part 61. The length of the shape memory alloy mesh 62 changes at the phase change temperature to drive the segmented parts 61 and change the size of the exhaust port 60 of the tail nozzle 6.

[0037] Using a shape memory alloy as an actuating mechanism to control the nozzle area of the tail nozzle 6 can effectively avoid the problem of noise without adding too much weight and complex mechanisms. The shape memory alloy mesh 62 can be deformed when the exhaust gas of the tail nozzle 6 reaches the phase transition temperature by setting the phase transition temperature to match the corresponding working state, so that the exhaust port 60 of the tail nozzle 6 reaches the preset size, effectively reducing noise.

[0038] At the same time, the shape memory alloy mesh 62 can cover more positions of the segmented part 61 in a more lightweight manner, reducing the use of materials while ensuring the deformation amount of the segmented part 61.

[0039] Among them, the shape memory alloy referred to in this embodiment can be a nickel-titanium alloy, or can include but is not limited to copper-nickel alloy, copper-aluminum alloy, copper-zinc alloy. In other embodiments, it can also be other known shape memory alloy materials. In the description of this embodiment, the axial direction and the circumferential direction respectively refer to the axial direction and the circumferential direction relative to the tail nozzle 6.

[0040] In this embodiment, the size change amount of the shape memory alloy can be obtained by numerical simulation methods based on, but not limited to, the deformation coefficient of the shape memory alloy. For example, a multi-disciplinary and multi-condition optimization method of aerodynamic-noise coupling can be used. By according to the relationship between the noise, aerodynamic performance and the size of the exhaust port 60 at different working state points, such as during engine takeoff, cruise, and landing, the optimal exhaust port size for each state can be obtained, so as to determine the size change of the shape memory alloy. Thus, while comprehensively improving the aerodynamic performance at different working state points, the noise level is always maintained within the range required by airworthiness, reducing the air resistance of the tail nozzle during different working states of engine takeoff, cruise, and landing, as well as the aerodynamic interference resistance between the engine and the aircraft.

[0041] In a preferred embodiment, the structural design scheme of the tail nozzle 6 is applied to the inner nozzle. Since the exhaust temperature is relatively high, heat insulation measures can be further set, such as coating a heat insulation ceramic coating on the inner side of the tail nozzle 6, or controlling the shape memory alloy powder elements by additive manufacturing. For example, a formula with 25% Ni, 25% Pd, 16.6% Ti, 16.7% Hf, and 16.6% Zf by mass percentage can increase the phase transition temperature to 700°C - 800°C.

[0042] In this embodiment, the cross-sectional shape of the shape memory alloy wire 621 can include one or a combination of more of a circle, a rectangle, an ellipse, a triangle, and a polygon. The shape memory alloy wire 621 can be one or a combination of more of a straight shape, a segmented shape, and a curved shape.

[0043] In a preferred embodiment, at least a portion of the shape memory alloy wires 621 extend to the edge of each slice portion 61, and at least a portion of the shape memory alloy wires 621 extending to the edge of the slice portion 61 are cross-connected with each other. Thus, the shape memory alloy wires 621 can cover each position of the slice portion to the maximum extent, and the cross-shaped memory alloy wires can provide a greater deformation force, and the deformation control of the slice portion is stronger, so as to achieve a greater degree of deformation of the slice portion.

[0044] In this embodiment, the shape of the slice portion 61 can be one or a combination of a sawtooth shape, an arc shape, and a trapezoid shape. Of course, in other embodiments, the slice portion can also be a slice portion of other shapes. The connection between the memory alloy wire 621 and the slice portion in this embodiment is not limited by the shape of the slice portion 61.

[0045] In a preferred embodiment, the shape memory alloy wire 621 is directly coated on the segment portion 61 by additive manufacturing. In another preferred embodiment, the shape memory alloy wire 621 formed separately can be fixedly connected to the segment portion 61. Of course, in other embodiments, other known connection methods can also be used to connect the shape memory alloy wire 621 to the segment portion 61.

[0046] In the embodiment of the separately formed shape memory alloy wire 621, the separately formed shape memory alloy wire 621 may be formed by one or more of casting, forging, and machining methods, or may be separately formed by other known processing methods.

[0047] In a preferred embodiment, the outer surface of each slice portion 61 can be formed into an indented receiving groove by removing material, wherein the receiving groove is connected or coated with a shape memory alloy wire 621. Thus, the shape memory alloy wire and the slice portion 61 can be more closely connected to avoid peeling. Of course, in other embodiments, the receiving groove can also be preset when the slice portion is formed, and in other embodiments, the shape memory alloy wire 621 can also be directly set on the surface of the slice portion 61.

[0048] In a preferred embodiment, the shape memory alloy wire 621 includes at least two deformation segments with different phase transition temperatures, and each deformation segment expands the segment portion 61 to different positions at at least two different temperatures, so that the exhaust port 60 of the tail nozzle 6 is changed to at least two different sizes.

[0049] In a further preferred embodiment, the shape memory alloy mesh includes three deformation segments along the axial direction with different phase change temperatures. Each deformation segment deforms the segmented part 61 to different positions at three different temperatures, so that the exhaust port 60 of the tail nozzle 6 is changed to three different sizes. Thus, for the engine in three states of idle, climb, and cruise, the tail nozzle 6 has different exhaust temperatures in these three states. Through the contraction or elongation of the shape memory alloy wire 621 at different temperatures, the deployment or closing of the tail nozzle 6 is realized. Thus, in three different states, the exhaust port 60 of the tail nozzle 6 can reach its respective optimal size. Coupled with the initial shape of the tail nozzle 6, the optimal noise and aerodynamic performance can be maintained in most working states of the engine.

[0050] In a preferred embodiment, the deformation segments with different phase change temperatures are processed from the same shape memory alloy by using different additive manufacturing process parameters. For example, in Figure 4 the shown shape memory alloy mesh 62 can be divided into a total of 4 deformation segments, namely m, n, o, and p, according to different phase change temperatures. In other embodiments, there may be more or fewer segments. The phase change temperatures of these segments m, n, o, and p vary along the axial direction of the segmented part 61, thereby enabling multi-segment deformation. Among them, whether in the Figure 4 shown preferred embodiment or other embodiments, the junction of the deformation segments with different phase change temperatures is the intersection point of the shape memory alloy wire 621. Thus, the transition position of the deformation segments with different phase change temperatures can have higher strength.

[0051] In the example as Figures 5 - 8 shown, in the embodiment of 4 deformation segments, the shape memory alloy mesh includes 4 deformation segments along the axial direction with different phase change temperatures. Each deformation segment deforms the segmented part 61 from the initial state a to states b, c, d, and e at 4 different temperatures, so that the exhaust port 60 of the tail nozzle 6 is changed to 4 different sizes.

[0052] In a preferred embodiment, the additive manufacturing process parameters can be one or more of laser power, scanning rate, and scanning spacing. Through the test of different specimens formed by changing the laser power resulting in the change of laser energy density, changing the scanning rate resulting in the change of laser energy density, and changing the scanning spacing resulting in the change of laser energy density, it can be known that the phase change temperature generally increases with the increase of the laser energy density used for forming.

[0053] Thus, in a preferred embodiment, different laser energy densities can be obtained by adjusting one or more of the laser power, scanning rate, and scanning spacing. By using different laser energy densities to form each deformation segment in the deformation unit, each deformation segment can have a different phase transition temperature. Among them, the laser energy density corresponding to each target phase transition temperature can be determined by means of multiple trials and errors.

[0054] To verify that multiple deformation segments can achieve multiple deformations, each deformation segment in the deformation unit can be formed by using different scanning rates, so that each deformation segment has a different phase transition temperature. A nickel-titanium alloy (NiTi) structure with multi-action characteristics prepared by selective laser melting. When preparing this structure, different laser scanning speeds (400, 500, 800 mm / s respectively) are selected for different parts, but the laser power (120 W), scanning spacing (80 μm), and powder layer thickness (30 μm) are kept unchanged. The main difference between the three circular structures lies in the different regions corresponding to different laser scanning speeds (for example, one is 400, 500, 800 mm / s clockwise, another is 500, 400, 800 mm / s clockwise, and the last one is 800, 500, 400 mm / s clockwise), that is, the arrangement and combination of the nickel-titanium alloy (NiTi) parts prepared at different scanning speeds are different. After deforming these three circles and putting them into a water bath, as the temperature rises, the shapes gradually recover, indicating that they all have multi-action deformation characteristics.

[0055] In a preferred embodiment, the deformation segments with different phase transition temperatures are sequentially scanned by laser along the extension direction of the shape memory alloy wire 621, and the material crystal phases between adjacent deformation segments with different phase transition temperatures transition smoothly. Since the same shape memory alloy is used, the deformation segments of the shape memory alloy wire 621 still form an integral body. And through laser scanning, when scanning a deformation segment, the adjacent deformation segments will also be heated, making the crystal phases between the deformation segments change slowly. Therefore, no stress concentration will occur at the junction between the deformation segments, ensuring the strength of the shape memory alloy wire 621 during repeated deformation.

[0056] The present invention uses a shape memory alloy as an actuating mechanism to change the control area of the nozzle of the tail nozzle at different temperatures, thereby effectively avoiding the problem of noise without adding too much weight and complex mechanisms.

[0057] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that this is only an example. The protection scope of the present invention is defined by the appended claims. Without departing from the principles and essence of the present invention, those skilled in the art can make various changes or modifications to these embodiments, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A tail nozzle for an aeroengine, comprising a plurality of segmented parts, the segmented parts surrounding an exhaust port of the tail nozzle, characterized in that, A shape memory alloy mesh is formed on the outer side of the slice portion, and the shape memory alloy mesh includes a shape memory alloy wire, wherein the shape memory alloy mesh extends in the circumferential direction to cover each of the slice portions, and the shape memory alloy mesh changes in length at a phase change temperature to drive the slice portion and change the size of the exhaust port of the tail nozzle; The shape memory alloy wire comprises at least two deformation segments with different phase transition temperatures, and each of the deformation segments expands the slice portion to different positions at at least two different temperatures, so that the exhaust port of the tail nozzle is changed into at least two different sizes; The deformation segments with different phase change temperatures are formed by processing the same shape memory alloy using different additive manufacturing process parameters.

2. The exhaust nozzle according to claim 1, characterized in that, The cross-sectional shape of the shape memory alloy wire includes one or a combination of circular, elliptical and polygonal shapes.

3. The exhaust nozzle according to claim 1, characterized in that, The shape memory alloy wire is in a straight line shape, a segmented shape, a curved shape, or a combination of the above.

4. The exhaust nozzle according to claim 3, characterized in that, At least a portion of the shape memory alloy wires extend to the edge of each of the slice portions, and at least a portion of the shape memory alloy wires extending to the edge of the slice portions are cross-connected to each other.

5. The exhaust nozzle according to claim 1, characterized in that, The shape of the slice portion is one or a combination of the following: a sawtooth shape, an arc shape, and a trapezoid shape.

6. The exhaust nozzle according to claim 1, characterized in that, The shape memory alloy wire is directly coated on the segment part by means of additive manufacturing, or the shape memory alloy wire is fixedly connected to the segment part by being separately formed.

7. The exhaust nozzle according to claim 6, characterized in that, The outer surface of each of the slice parts is formed into a sunken receiving groove by removing material, wherein the shape memory alloy wire is connected or coated in the receiving groove.

8. The nozzle according to claim 6, characterized in that, The independently formed shape memory alloy wire is processed by one or more of casting, forging and machining.

9. The exhaust nozzle according to claim 1, characterized in that, The shape memory alloy mesh includes three deformation segments with different phase change temperatures along the axial direction, and each deformation segment deforms the slice portion to different positions at three different temperatures, so that the exhaust port of the tail nozzle is changed into three different sizes.

10. The exhaust nozzle according to claim 1, characterized in that, The additive manufacturing process parameters are one or more parameters of laser power, scanning rate and scanning spacing, and / or the shape memory alloy is nickel-titanium alloy.

11. The exhaust nozzle according to claim 1, characterized in that, The deformation segments with different phase change temperatures are formed by sequentially scanning the laser along the extension direction of the shape memory alloy wire, and the material crystal phases between adjacent deformation segments with different phase change temperatures transition smoothly.

12. The exhaust nozzle according to claim 1, characterized in that, The junction of the deformation segments with different phase transition temperatures is the intersection of the shape memory alloy wires.

13. An aeroengine, characterized in that, The aircraft engine comprises the tail nozzle according to any one of claims 1 to 12, wherein the tail nozzle is an internal nozzle and / or an external nozzle of the aircraft engine.

14. An aircraft, characterized in that, The aircraft comprises one or more aircraft engines according to claim 13.

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