Tail nozzle, aeroengine and aircraft

Abstract

The present invention discloses a tail nozzle, an aero-engine and an aircraft, wherein the tail nozzle comprises a plurality of slices, the slices are arranged to form an exhaust port of the tail nozzle, and the tail nozzle is characterized in that a shape memory alloy coating is formed on the outer side of the slices, wherein the shape memory alloy coating comprises at least two deformation segments with different phase change temperatures along the axial direction, and each deformation segment stretches the slices 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 present invention adopts shape memory alloy as an actuating mechanism to change the exhaust port area of the tail nozzle at different temperatures, thereby effectively avoiding the problem of noise without adding too much weight and complex mechanism.

Description

Technical Field

[0001] The invention relates to a tail nozzle, an aero-engine and an aircraft. Background Art

[0002] The tail nozzle of an aircraft engine has different working states when it is working. By changing the outlet size of the tail nozzle, the working state of the engine can be changed, which can enable the engine to obtain good performance in various working states. However, the tail nozzle with adjustable exhaust port is usually a mechanical structure, which is complex and heavy, and the mechanical transmission components are unreliable when working at high temperatures. Therefore, civil turbofan engines use non-adjustable convergent tail nozzles.

[0003] At present, high bypass ratio turbofan engines usually use non-adjustable convergent tail nozzles, also known as subsonic nozzles with fixed exhaust ports, including zigzag tail nozzles with noise reduction functions. They have the simplest structure and the lightest weight. Almost all civil turbofan engines such as CFM56, PW4000, RB211, and GE90 use this tail nozzle. Although when the available pressure drop ratio of the nozzle is greater than the critical pressure drop ratio (1.85), the gas cannot be fully expanded in the convergent tail nozzle, but when the flight speed is not large (Ma≤1.5), the energy lost by the gas due to incomplete expansion is small, so it is appropriate to use this simple convergent tail nozzle.

[0004] However, in addition to the energy loss caused by incomplete expansion of combustion gas (resulting in reduced engine efficiency), with the increasing requirements for environmental indicators of aviation engines, the noise problem caused by different jet velocities at different operating points of the engine has become increasingly prominent. Although a serrated noise reduction tail nozzle has been designed for this purpose, 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 in the prior art that aircraft engines cannot avoid making loud noises in different working states while ensuring simple structure and light weight, and to provide a tail nozzle, an aircraft engine and an aircraft.

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

[0007] A tail nozzle, used for an aircraft engine, comprises a plurality of slice portions, wherein the slice portions are arranged to form an exhaust port of the tail nozzle, and is characterized in that a shape memory alloy coating is formed on the outer side of the slice portions, wherein the shape memory alloy coating comprises at least two deformation segments with different phase change temperatures along the axial direction, 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 to at least two different sizes.

[0008] Using shape memory alloy as the actuating mechanism to control the exhaust port area of the tail nozzle can effectively avoid the noise problem without adding too much weight and complex mechanism. The shape memory alloy coating 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, multiple deformation sections can ensure that the tail nozzle reaches its own optimal exhaust port size in different working conditions. Combined with the initial shape of the tail nozzle, it can maintain the optimal noise and aerodynamic performance in most working conditions of the engine.

[0010] Preferably, the thickness of the shape memory alloy coating is one or a combination of uniform thickness, wavy undulations, and sawtooth undulations.

[0011] Preferably, the shape of the slice portion is a sawtooth shape, an arc shape, a trapezoidal shape, or a combination of more.

[0012] Preferably, the shape memory alloy coating includes three deformation segments with different phase change temperatures along the axial direction, and each of the deformation segments expands 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.

[0013] Preferably, the shape memory alloy coating is directly coated on the segment portion by means of additive manufacturing, or the shape memory alloy coating is fixedly connected to the segment portion by being separately formed.

[0014] 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 coating is connected to or coated in the receiving groove.

[0015] Preferably, the separately formed shape memory alloy coating is formed by one or more of casting, forging and machining.

[0016] Preferably, the deformation segments with different phase change temperatures are formed by processing the same shape memory alloy using different additive manufacturing process parameters.

[0017] Preferably, 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.

[0018] Preferably, the deformation segments with different phase change temperatures are formed by sequentially scanning the laser along the axial direction, and the material crystal phases between adjacent deformation segments with different phase change temperatures transition smoothly.

[0019] An aeroengine, characterized in that the aeroengine includes the tail nozzle, wherein the tail nozzle is the inner nozzle and / or the outer nozzle of the aeroengine.

[0020] An aircraft, characterized in that the aircraft includes the aeroengine.

[0021] The positive and progressive effects of the present invention are as follows: Shape memory alloy is used as the actuating mechanism to change the area of the exhaust port of the tail nozzle at different temperatures, thereby effectively avoiding the problem of noise without adding too much weight and complex mechanisms. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of the aeroengine according to a preferred embodiment of the present invention.

[0023] Figure 2 It is a schematic structural diagram of the tail nozzle according to a preferred embodiment of the present invention.

[0024] Figure 3 It is a schematic structural diagram of the segmented part according to a preferred embodiment of the present invention.

[0025] Figure 4 It is Figure 3 The sectional structural diagram in the A-A direction in

[0026] Figure 5 It is a deformation schematic diagram of the segmented part at the first phase change temperature according to a preferred embodiment of the present invention.

[0027] Figure 6 It is a deformation schematic diagram of the segmented part at the second phase change temperature according to a preferred embodiment of the present invention.

[0028] Figure 7 It is a deformation schematic diagram of the segmented part at the third phase change temperature according to a preferred embodiment of the present invention. Detailed Embodiments

[0029] The present invention will be further described below by way of examples, but the present invention is not limited to the scope of the described examples.

[0030] As Figure 1 shown, this embodiment discloses an aeroengine mainly for an aircraft, and the aircraft may include one or more aeroengines of this embodiment. Among them, as Figure 1As shown, this embodiment exemplarily shows a specific structure of an aircraft engine, 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 aircraft engine. In aircraft engines with other structures, the tail nozzle 6 can also be used in the corresponding nozzle structure.

[0031] like Figures 2 - 3 As shown, the tail nozzle 6 of this embodiment includes a plurality of slice portions 61, which are arranged to form an exhaust port 60 of the tail nozzle 6. A shape memory alloy coating 62 is formed on the outer side of the slice portions 61, wherein the shape memory alloy coating 62 includes at least two deformation segments with different phase change temperatures along the axial direction, and each deformation segment expands the slice portion 61 to different positions at at least two different temperatures, so that the exhaust port of the tail nozzle is changed to at least two different sizes.

[0032] Using shape memory alloy as the actuating mechanism to control the nozzle area of the tail nozzle 6 can effectively avoid the noise problem without adding too much weight and complex mechanism. The shape memory alloy coating 62 can match the corresponding working state through the setting of the phase change temperature, and deforms when the exhaust of the tail nozzle 6 reaches the phase change temperature, so that the exhaust port 60 of the tail nozzle 6 reaches the preset size, effectively reducing noise.

[0033] At the same time, multiple deformation segments can ensure that the tail nozzle 6 reaches its own optimal exhaust port 60 size in different working conditions. In addition, the initial shape of the tail nozzle 6 can maintain the optimal noise and aerodynamic performance in most working conditions of the engine.

[0034] The shape memory alloy referred to in this embodiment may be a nickel-titanium alloy, and may also include but not be limited to a copper-nickel alloy, a copper-aluminum alloy, and a copper-zinc alloy. In other embodiments, other known shape memory alloy materials may also be used. In the description of this embodiment, the axial direction and the circumferential direction refer to the axial direction and the circumferential direction relative to the tail nozzle 6, respectively.

[0035] In this embodiment, the size change of the shape memory alloy can be calculated by numerical simulation method based on the deformation coefficient of the shape memory alloy, but is not limited to it. For example, the aerodynamic-noise coupling multidisciplinary multi-operating condition optimization method can be used to obtain the optimal exhaust port size in each state according to the relationship between the noise, aerodynamic performance and the size of the exhaust port 60 at different working state points, such as engine takeoff, cruising, and landing, so as to determine that the size of the shape memory alloy has changed, so that while the aerodynamic performance at different working state points is comprehensively improved, the noise level is always kept within the range of airworthiness requirements, and the tail nozzle air resistance of the engine in different working states of takeoff, cruising, and landing, as well as the aerodynamic interference resistance between the engine and the aircraft are reduced.

[0036] In a preferred embodiment, the structural design of the tail nozzle 6 is applied to the core nozzle. Since the exhaust temperature is relatively high, heat insulation measures can be further set, such as coating a heat-insulating ceramic coating on the inner side of the tail nozzle 6, or controlling the shape memory alloy powder elements through 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.

[0037] In this embodiment, the thickness of the shape memory alloy coating 62 is one or a combination of a uniform thickness, a wavy undulation, and a serrated undulation. The shape of the segmented part 61 is one or a combination of a serrated shape, an arc shape, and a trapezoidal shape. Of course, in other embodiments, it can also be a shape memory alloy coating 62 with other thickness variations and segmented parts with other shapes.

[0038] In a setting method of the shape memory alloy coating 62, the shape memory alloy coating 62 is directly coated on the segmented part 61 by additive manufacturing. In another setting method of the shape memory alloy coating 62, or a separately formed shape memory alloy coating 62 is fixedly connected to the segmented part 61.

[0039] In a further preferred embodiment, the separately formed shape memory alloy coating 62 is processed by one or more of casting, forging, and machining, and can also be separately processed and formed by other known processing methods.

[0040] In a preferred embodiment, the outer surface of each segmented part 61 forms an indented receiving groove by material removal. Among them, a shape memory alloy coating 62 is connected or coated in the receiving groove. Thus, the shape memory alloy coating 62 and the segmented part 61 can be more tightly connected to avoid peeling. Of course, in other embodiments, the receiving groove can also be preset during the forming of the segmented part 61. In some other embodiments, the shape memory alloy coating 62 can also be directly provided on the surface of the segmented part 61.

[0041] As Figures 4 - 7 shown, in a preferred embodiment, the shape memory alloy coating 62 includes three deformation segments 621, 622, and 623 with different phase transition temperatures along the axial direction. The deformation segments 621, 622, and 623 expand the segmented part 61 from the initial position a to different positions b, position c, and position d at three different temperatures, so that the exhaust port of the tail nozzle is changed into three different sizes.

[0042] 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. The additive manufacturing process parameters can be one or more of laser power, scanning rate, and scanning pitch. Through the tests 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 pitch 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.

[0043] Therefore, in a preferred embodiment, by adjusting one or more of the laser power, scanning rate, and scanning pitch, different laser energy densities can be obtained, and by using different laser energy densities to form each deformation segment in the deformation unit, each deformation segment can have different phase change temperatures. Among them, the laser energy density used for each target phase change temperature can be determined by the way of multiple trials and errors.

[0044] In order 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 change temperature. A nickel-titanium alloy (NiTi) structure with multi-action characteristics is 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 pitch (80 μm), and powder bed 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 by different scanning speeds are different. After deforming these three circles and putting them into a water bath, as the temperature rises, the shapes all gradually recover, indicating that they all have multi-action deformation characteristics.

[0045] In a preferred embodiment, the deformation segments with different phase change temperatures are sequentially scanned by laser along the extending direction of the shape memory alloy coating 62, and the material crystal phases between adjacent deformation segments with different phase change temperatures transition smoothly. Since they are made of the same shape memory alloy, the deformation segments of the shape memory alloy coating 62 still form a whole, and during the laser scanning, the adjacent deformation segments will also be heated when scanning the deformation segments, so that the crystal phases between the deformation segments change slowly. Therefore, stress concentration will not occur at the junction of the deformation segments, ensuring the strength of the shape memory alloy coating 62 during the repeated deformation process.

[0046] The present invention uses a shape memory alloy as an actuating mechanism to change the area of the exhaust port of the control nozzle at different temperatures, thereby effectively avoiding the problem of noise without adding excessive weight and complex mechanisms.

[0047] 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, and the protection scope of the present invention is defined by the appended claims. Without departing from the principle 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 nozzle, for an aeroengine, comprising a plurality of segment parts, the segment parts surrounding to form an exhaust port of the nozzle, characterized in that, A shape memory alloy coating is formed on the outer side of the segment portion, wherein the shape memory alloy coating includes at least two deformation segments with different phase change temperatures along the axial direction, and each of the deformation segments 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; The deformation segments with different phase change temperatures are formed by processing the same shape memory alloy using different additive manufacturing process parameters; The deformation segments with different phase change temperatures are formed by sequentially scanning the laser along the axial direction, and the material crystal phases between adjacent deformation segments with different phase change temperatures transition smoothly.

2. The exhaust nozzle according to claim 1, wherein The thickness of the shape memory alloy coating is one or a combination of uniform thickness, wavy undulations, and sawtooth undulations.

3. 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.

4. The exhaust nozzle according to claim 1, characterized in that, The shape memory alloy coating includes three deformation segments with different phase change temperatures along the axial direction, and each of the deformation segments expands 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.

5. The exhaust nozzle according to claim 1, characterized in that, The outer surface of each segment portion is formed into a sunken receiving groove by removing material, wherein the shape memory alloy coating is connected to or coated in the receiving groove.

6. The exhaust nozzle according to claim 1, characterized in that, The separately formed shape memory alloy coating is formed by one or more of casting, forging and machining.

7. 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.

8. An aeroengine, characterized in that, The aircraft engine comprises the tail nozzle according to any one of claims 1 to 7, wherein the tail nozzle is an internal nozzle and / or an external nozzle of the aircraft engine.

9. An aircraft, characterized in that, The aircraft comprises one or more aircraft engines according to claim 8.

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