An S-bend nozzle with deformation suppression structure and aircraft engine

Abstract

The present invention relates to an S-bend nozzle and an aero-engine with a deformation suppression structure, belonging to the field of aero-engines. The invention comprises an S-bend nozzle convergent section and an S-bend nozzle equivalent section. The inlet end of the S-bend nozzle convergent section is connected to the outlet of the engine's high-temperature turbine, with the connection surface being the nozzle inlet, and the outlet end thereof being connected to the inlet end of the S-bend nozzle equivalent section, and the outlet end of the S-bend nozzle equivalent section being connected to the nozzle exhaust port. The invention also comprises a deformation suppression component provided on the outer layer of the S-bend nozzle wall. The S-bend nozzle wall is a composite sandwich structure, and from the inside to the outside along the vertical direction of the wall, the nozzle wall inner layer, the nozzle wall sandwich, and the nozzle wall outer layer are respectively provided. The present invention adopts a structure of providing circumferential reinforcement ribs on the outer layer of the nozzle wall and applying a composite sandwich nozzle wall to solve the local deformation and overall instability of the S-bend nozzle caused by the complex aerodynamic conditions and the complex structure of the engine in the prior art, and adapt to the more extreme aerodynamic boundaries of the engine.

Description

Technical Field

[0001] The present invention belongs to the field of aero-engines, and in particular relates to an S-bend nozzle with a deformation suppression structure and an aero-engine. Background Art

[0002] With the development of modern aviation weapons and infrared guidance technology, the survival environment of fighter jets in modern warfare has become increasingly harsh. Among the detectable signal characteristics of an aircraft, the engine tail nozzle is the strongest source of infrared radiation and the main source of radar reflection. The S-bend nozzle configuration has a unique advantage in reducing infrared radiation and radar reflection. The S-bend surface can shield the high-temperature components inside the engine, and the non-axisymmetric outlet form can enhance the mixing of the tail jet with the external atmosphere, greatly reducing the infrared radiation characteristics. At the same time, the incident electromagnetic waves are repeatedly refracted and dissipated within the S-bend channel, reducing the electromagnetic scattering signal of the tail nozzle. Therefore, the S-bend nozzle has become a research focus of low-observable technology.

[0003] On February 22, 2022, the online first paper "Study on Fluid-Solid Coupling Characteristics of Double S-bend Nozzles" in "Propulsion Technology" studied the structural deformation characteristics of the S-bend convergent nozzle and the internal / external flow characteristics of the nozzle under its influence, but did not propose a clear strategy and method to suppress the deformation of the S-bend nozzle. For the S-bend nozzle, the aerodynamic load of the non-uniform flow characteristics and the complex structure itself cause complex stress and strain distribution on the wall of the elastomer structure of the S-bend nozzle, thereby producing corresponding structural deformation characteristics, and the deformation characteristics of the S-bend nozzle structure will in turn change its internal flow characteristics, causing the aerodynamic characteristics of the S-bend nozzle to be significantly changed, seriously affecting the working stability of the S-bend nozzle, causing the tail nozzle structure to become unstable, and affecting the overall performance of the engine. Taking the traditional S-bend nozzle with a wall thickness of 3mm as an example, the wall deformation cloud map of the traditional S-bend nozzle after experiencing the interaction between the aerodynamic load and its complex structure is shown below. Figure 1 As shown in the figure, the upper and lower walls of the nozzle are severely deformed at an axial distance of 4:10 to 6:10 from the entrance of the second bend of the S-bend, with the maximum deformation reaching 44mm. At the nozzle exhaust port, the upper wall of the nozzle outlet is locally deformed, with the deformation reaching 29mm. The surface deformation of the traditional S-bend nozzle after experiencing the interaction between aerodynamic loads and its complex structure is shown in the figure. Figure 2 As shown in the figure, at an axial distance of 4:10 to 6:10 from the entrance of the second bend of the S-bend, the upper and lower walls deform and bulge outward along the normal direction of the profile. This deformation causes the nozzle exhaust port to deflect upward as a whole, significantly affecting the aerodynamic characteristics and operational stability of the S-bend nozzle. The common method to suppress S-bend nozzle deformation is to increase the nozzle wall thickness, but this approach not only increases nozzle weight but also affects the nozzle's assembly with the aircraft engine and aircraft. Summary of the Invention

[0004] Technical issues to be solved:

[0005] In order to avoid the shortcomings of the existing technology, the present invention provides an S-bend nozzle with a deformation suppression structure, which adopts a structure in which circumferential reinforcement ribs are set on the outer layer of the nozzle wall and a composite sandwich nozzle wall is applied to solve the local deformation and overall instability of the S-bend nozzle caused by the complex aerodynamic conditions of the engine and the complex structure of the engine in the existing technology, and adapt to the more extreme aerodynamic boundaries of the engine.

[0006] The technical solution of the present invention is: an S-bend nozzle with a deformation suppression structure, comprising an S-bend nozzle convergent section and an S-bend nozzle equivalent section; the inlet end of the S-bend nozzle convergent section is connected to the outlet of the engine high-temperature turbine, the connecting surface is the nozzle inlet, and its outlet end is connected to the inlet end of the S-bend nozzle equivalent section, and the outlet end of the S-bend nozzle equivalent section is connected to the nozzle exhaust port; it also includes a deformation suppression component arranged on the outer layer of the S-bend nozzle wall, and the S-bend nozzle wall is a composite sandwich structure, and from the inside to the outside along the vertical direction of the wall are respectively the inner layer of the nozzle wall, the interlayer of the nozzle wall, and the outer layer of the nozzle wall.

[0007] A further technical solution of the present invention is: the S-bend nozzle convergent section includes an S-bend first bend section and an S-bend second bend section along the flow direction, wherein the S-bend first bend section deflects downward and the S-bend second bend section deflects upward, the outlet of the S-bend first bend section is the inlet of the S-bend second bend section, hereinafter referred to as the S-bend second bend end inlet, the ratio of the length of the S-bend nozzle convergent section and the S-bend nozzle equivalent section along the nozzle inlet axis direction is between 8:1 and 7:1, and the ratio of the length of the S-bend first bend end and the S-bend second bend section along the nozzle inlet axis direction is between 2:4 and 2:3.

[0008] A further technical solution of the present invention is: the deformation suppression component includes four circumferential reinforcement ribs, namely the first circumferential reinforcement rib, the second circumferential reinforcement rib, the third circumferential reinforcement rib and the S-bend nozzle equivalent section circumferential reinforcement rib; wherein the first circumferential reinforcement rib, the second circumferential reinforcement rib and the third circumferential reinforcement rib are distributed in sequence along the axial direction on the outer wall surface of the second bend section of the S-bend; the S-bend nozzle equivalent section circumferential reinforcement rib is arranged on the outer wall surface of the S-bend nozzle equivalent section.

[0009] A further technical solution of the present invention is: the first circumferential reinforcement rib is located at the entrance of the second bend section of the S-bend, the ratio of the distance between the second circumferential reinforcement rib and the entrance end of the second bend section of the S-bend to the length of the second bend section of the S-bend along the axis of the entrance of the second bend section of the S-bend is 3:10 to 4:10, and the ratio of the distance between the third circumferential reinforcement rib and the entrance end of the second bend section of the S-bend to the length of the second bend section of the S-bend along the axis of the entrance of the second bend section of the S-bend is 6:10 to 7:10.

[0010] A further technical solution of the present invention is that the radial length of the first circumferential reinforcing rib, the second circumferential reinforcing rib and the third circumferential reinforcing rib is 25mm to 35mm, the axial thickness is 30mm to 40mm, and they are all fixed to the nozzle wall.

[0011] A further technical solution of the present invention is that the radial length of the circumferential reinforcement rib of the equivalent section of the S-bend nozzle is 25mm to 35mm, and the axial thickness is equal to the length of the equivalent section of the S-bend nozzle.

[0012] A further technical solution of the present invention is that the inner layer thickness of the nozzle wall is 0.5mm-1.0mm, the interlayer thickness of the nozzle wall is 1mm-4mm, and the outer layer thickness of the nozzle wall is 0.5mm-1.0mm.

[0013] A further technical solution of the present invention is that the nozzle wall interlayer material is selected from ceramic-based composite materials, which have high strength, good oxidation resistance and corrosion resistance in the operating temperature range of the S-bend nozzle.

[0014] A further technical solution of the present invention is that the materials of the inner layer and the outer layer of the nozzle wall are selected from GH2706 high-temperature corrosion-resistant alloy, which has a higher elastic modulus and a lower material density while ensuring high temperature resistance.

[0015] An aero-engine is provided, wherein an S-bend nozzle with a deformation suppression structure is installed at a high-temperature turbine outlet of the aero-engine.

[0016] Beneficial effects

[0017] The beneficial effects of the present invention are as follows: the S-bend nozzle with a deformation suppression structure using the technical solution of the present invention effectively suppresses the structural deformation of the second bend section of the S-bend due to aerodynamic loads and structural effects through the first circumferential reinforcement ribs, the second circumferential reinforcement ribs and the third circumferential reinforcement ribs; the circumferential reinforcement ribs of the equivalent section of the S-bend nozzle effectively suppress the structural deformation of the equivalent section of the S-bend nozzle due to aerodynamic loads and structural effects. Compared with the conventional S-bend nozzle, the degree of deformation suppression can reach more than 70%; in addition, the nozzle wall is a composite sandwich structure, which is radially from the inside to the outside and consists of the inner layer of the nozzle wall, the interlayer of the nozzle wall and the outer layer of the nozzle wall, thereby improving the structural instability problem of the S-bend nozzle caused by excessive aerodynamic loads and structural effects.

[0018] The present invention's key challenge lies in its use of a composite sandwich structure formed by four circumferential ribs and the nozzle wall. This eliminates the significant increase in nozzle weight caused by the prior art's single-pronged approach of increasing thickness to suppress deformation, while still maintaining the required structural strength for the S-bend nozzle. Furthermore, the four circumferential ribs are positioned at and near the point of maximum deformation, effectively increasing the nozzle's structural strength. Furthermore, due to the optimal selection of circumferential rib thickness and radial length, the nozzle's weight is reduced by 22.9% compared to conventional S-bend nozzles, remaining within a reasonable weight increase. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a cloud diagram of the wall deformation of a traditional S-bend nozzle after experiencing the interaction between aerodynamic loads and its complex structure;

[0020] Figure 2 This is the surface deformation profile of the traditional S-bend nozzle after experiencing the interaction between aerodynamic load and its complex structure;

[0021] Figure 3 2 is a schematic structural diagram of an S-bend nozzle with a deformation suppression structure according to an embodiment of the present invention;

[0022] Figure 4 3. This is a front view of an optional S-bend nozzle with a deformation suppression structure according to an embodiment of the present invention;

[0023] Figure 5 2. This is a top view of an S-bend nozzle with a deformation suppression structure, which may be selected according to an embodiment of the present invention;

[0024] Figure 6 This is a schematic diagram of the overall structure of an S-bend nozzle with a deformation suppression structure, which can be selected according to an embodiment of the present invention;

[0025] Figure 7 is a cross-sectional view of a nozzle wall of an S-bend nozzle with a deformation suppression structure, which is optional according to an embodiment of the present invention;

[0026] Explanation of the accompanying symbols: 1. S-bend nozzle convergence section; 2. S-bend nozzle equivalent section; 3. Nozzle inlet; 4. Nozzle exhaust port; 5. S-bend first bend section; 6. S-bend second bend section; 7. First circumferential reinforcement rib; 8. Second circumferential reinforcement rib; 9. Third circumferential reinforcement rib; 10. S-bend nozzle equivalent section circumferential reinforcement rib; 11. Inner layer of nozzle wall; 12. Interlayer of nozzle wall; 13. Outer layer of nozzle wall. DETAILED DESCRIPTION

[0027] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0028] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0029] The embodiment of the present invention is an S-bend nozzle with a deformation suppression structure, such as Figure 3 As shown, it includes: an S-bend nozzle convergent section 1, an S-bend nozzle equivalent section 2, and four circumferential reinforcement ribs 7, 8, 9, and 10. The inlet end of the S-bend nozzle convergent section 1 is connected to the engine high-temperature turbine outlet, with the connection surface being the nozzle inlet 3. The outlet end of the S-bend nozzle convergent section 1 is connected to the inlet end of the S-bend nozzle equivalent section 2, and the outlet end of the S-bend nozzle equivalent section 2 is connected to the nozzle exhaust port 4. The S-bend nozzle convergent section 1 includes an S-bend first bend section 5 and an S-bend second bend section 6. Circumferential reinforcement ribs 7, 8, 9, and 10 are respectively provided on the S-bend second bend section 6 and the S-bend nozzle equivalent section 2. The nozzle wall is a composite sandwich structure. From the inside to the outside along the vertical direction of the wall, they are the nozzle wall inner layer 11, the nozzle wall interlayer 12, and the nozzle wall outer layer 13.

[0030] The S-bend nozzle with a deformation suppression structure that applies the technical solution of the present invention effectively suppresses the structural deformation of the second bend section 6 of the S-bend due to aerodynamic loads and structural effects through the first circumferential reinforcement ribs 7, the second circumferential reinforcement ribs 8 and the third circumferential reinforcement ribs 9. The circumferential reinforcement ribs 10 of the equivalent section of the S-bend nozzle effectively suppress the structural deformation of the equivalent section 2 of the S-bend nozzle due to aerodynamic loads and structural effects. In addition, the nozzle wall is a composite sandwich structure, and from the inside to the outside along the vertical direction of the wall are the nozzle wall inner layer 11, the nozzle wall interlayer 12, and the nozzle wall outer layer 13, respectively, which improves the structural instability problem of the S-bend nozzle caused by excessive aerodynamic loads and structural effects.

[0031] Specifically, such as Figure 4As shown, the inlet of the S-bend nozzle convergent section 1 is connected to the outlet of the engine's high-temperature turbine, and the outlet of the S-bend nozzle convergent section 1 is connected to the inlet of the S-bend nozzle equivalent section 2. Airflow enters the nozzle inlet 3, flows through the S-bend nozzle convergent section 1 and the S-bend nozzle equivalent section 2, and finally exits through the nozzle exhaust port 4. The S-bend nozzle convergent section 1 includes the first S-bend section 5 and the second S-bend section 6 along the flow direction. The airflow deflects downward after passing through the first S-bend section 5 and upward after passing through the second S-bend section 6. The ratio of the lengths of the S-bend nozzle convergent section 1 and the S-bend nozzle equivalent section 2 along the nozzle inlet axis is between 8:1 and 7:1, and the ratio of the lengths of the S-bend first bend 5 and the S-bend second bend 6 along the nozzle inlet axis is between 2:4 and 2:3.

[0032] like Figure 5 As shown, the first circumferential reinforcing rib 7, the second circumferential reinforcing rib 8 and the third circumferential reinforcing rib 9 are provided in the second bend section 6 of the S-bend. The normal direction of the maximum section of the first circumferential reinforcing rib 7, the second circumferential reinforcing rib 8 and the third circumferential reinforcing rib 9 is the same as the normal direction of the nozzle section at the same position. Since the maximum deformation position of the S-bend nozzle occurs on the nozzle wall of the second bend section 6 of the S-bend, the first circumferential reinforcing rib 7 is located at the entrance of the second bend section 6 of the S-bend, and the distance between the second circumferential reinforcing rib 8 and the entrance end of the second bend section 6 of the S-bend is the same as the distance between the second circumferential reinforcing rib 8 and the entrance end of the second bend section 6 of the S-bend. The ratio of the length of the third circumferential reinforcing rib 9 along the inlet axis of the second S-bend segment 6 is 3:10 to 4:10. The ratio of the distance between the third circumferential reinforcing rib 9 and the inlet end of the second S-bend segment 6 and the length of the second S-bend segment 6 along the inlet axis of the second S-bend segment 6 is 6:10 to 7:10. To increase the structural stability of the nozzle while not excessively increasing its own weight, the three circumferential reinforcing ribs are 30mm to 40mm thick and 25mm to 35mm in radial length. They are fixedly connected to the outer layer 13 of the nozzle wall. The cross-sectional area of ​​the S-bend nozzle equivalent segment 2 remains unchanged along the flow direction. Because the S-bend nozzle equivalent segment 2 will deflect upward under the aerodynamic force of the high-temperature airflow and its own structural effects, the outer wall of the S-bend nozzle equivalent segment 2 is provided with S-bend nozzle equivalent segment circumferential reinforcing ribs 10 with a radial length of 25mm to 35mm and a thickness equal to the length of the S-bend nozzle equivalent segment 2.

[0033] In an embodiment of the present invention, a high-temperature airflow flows out from the engine turbine, flows into the S-bend nozzle convergent section 1 through the nozzle inlet 3, gradually accelerates in the nozzle, and when passing through the S-bend first bend section 5 and the S-bend second bend section 6, the airflow flow tube on the inner side of the bend contracts faster than the flow tube on the outer side due to the influence of the bending configuration. The airflow is accelerated more on the inner side of the bend than on the outer side, thereby forming a normal pressure gradient. The excessive pressure load causes the nozzle wall surface of the S-bend second bend section 6 to tend to bulge and deform outward, and the S-bend nozzle equivalent section 2 to tend to deflect upward. The first circumferential reinforcement rib 7, the second circumferential reinforcement rib 8, the third circumferential reinforcement rib 9 and the S-bend nozzle equivalent section circumferential reinforcement rib 10 fixed on the outer layer 13 of the nozzle wall effectively suppress the degree of deformation of this structure.

[0034] like Figure 7 As shown, the nozzle wall is a composite sandwich structure, and along the vertical direction of the wall from the inside to the outside are the nozzle wall inner layer 11, the nozzle wall interlayer 12, and the nozzle wall outer layer 13. The thickness of the nozzle wall inner layer 11 is between 0.5mm and 1.0mm, the thickness of the nozzle wall interlayer 12 is between 1mm and 4mm, and the thickness of the nozzle wall outer layer 13 is between 0.5mm and 1.0mm. Due to the setting of the composite sandwich structure, the overall stiffness of the nozzle wall is improved, and the risk of instability of the overall structure of the S-bend nozzle is reduced.

[0035] In order to further suppress the structural deformation of the S-bend nozzle, the material of the four circumferential reinforcement ribs 7, 8, 9, and 10 can be selected from GH2706 high-temperature corrosion-resistant alloy, which has a higher elastic modulus and lower material density while ensuring high-temperature resistance, and can effectively suppress the structural deformation of the S-bend nozzle.

[0036] In order to further reduce the risk of overall structural instability and deformation of the S-bend nozzle, the material of the nozzle wall interlayer 12 can be selected from ceramic-based composite materials, which have high strength, good oxidation resistance and corrosion resistance in the operating temperature range of the S-bend nozzle; the material of the nozzle wall inner layer 11 and the nozzle wall outer layer 13 can be selected from GH2706 high-temperature corrosion-resistant alloy. The nozzle wall composite structure of GH2706 high-temperature corrosion-resistant alloy-ceramic-based composite materials-GH2706 high-temperature corrosion-resistant alloy can effectively reduce the risk of overall structural instability and deformation of the S-bend nozzle, while meeting the indicator of low weight of the aircraft engine tail nozzle.

[0037] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. An S-bend nozzle with a deformation suppression structure, comprising an S-bend nozzle convergent section and an S-bend nozzle equivalent section; the inlet end of the S-bend nozzle convergent section is connected to the outlet of the engine high-temperature turbine, the connection surface is the nozzle inlet, the outlet end is connected to the inlet end of the S-bend nozzle equivalent section, and the outlet end of the S-bend nozzle equivalent section is connected to the nozzle exhaust port; characterized in that: The invention also includes a deformation suppression component provided on the outer layer of the S-bend nozzle wall, wherein the S-bend nozzle wall is a composite sandwich structure, and from the inside to the outside along the vertical direction of the wall, the nozzle wall inner layer, the nozzle wall sandwich layer, and the nozzle wall outer layer are respectively; The S-bend nozzle convergent section includes an S-bend first bend section and an S-bend second bend section along the flow direction, wherein the S-bend first bend section deflects downward, and the S-bend second bend section deflects upward, the outlet of the S-bend first bend section is the inlet of the S-bend second bend section, hereinafter referred to as the S-bend second bend end inlet, the ratio of the length of the S-bend nozzle convergent section to the S-bend nozzle equivalent section along the nozzle inlet axis is between 8:1 and 7:1, and the ratio of the length of the S-bend first bend end to the S-bend second bend section along the nozzle inlet axis is between 2:4 and 2:3; The deformation suppression component includes four circumferential reinforcement ribs, namely the first circumferential reinforcement rib, the second circumferential reinforcement rib, the third circumferential reinforcement rib and the S-bend nozzle equivalent section circumferential reinforcement rib; wherein the first circumferential reinforcement rib, the second circumferential reinforcement rib and the third circumferential reinforcement rib are sequentially distributed along the axial direction on the outer wall surface of the second bend section of the S-bend; the S-bend nozzle equivalent section circumferential reinforcement rib is provided on the outer wall surface of the S-bend nozzle equivalent section; The first circumferential reinforcing rib is located at the entrance of the second bend section of the S-bend, the ratio of the distance between the second circumferential reinforcing rib and the entrance end of the second bend section of the S-bend to the length of the second bend section of the S-bend along the axis of the entrance of the second bend section of the S-bend is 3:10 to 4:10, and the ratio of the distance between the third circumferential reinforcing rib and the entrance end of the second bend section of the S-bend to the length of the second bend section of the S-bend along the axis of the entrance of the second bend section of the S-bend is 6:10 to 7:10; The radial length of the first circumferential reinforcing rib, the second circumferential reinforcing rib, and the third circumferential reinforcing rib is 25 mm to 35 mm, the axial thickness is 30 mm to 40 mm, and they are all fixed to the nozzle wall; The nozzle wall interlayer material is selected from ceramic matrix composite materials, which have high strength, good oxidation resistance and corrosion resistance in the operating temperature range of the S-bend nozzle; The inner layer and the outer layer of the nozzle wall are made of GH2706 high-temperature corrosion-resistant alloy, which has a higher elastic modulus and a lower material density while ensuring high-temperature resistance.

2. The S-bend nozzle with a deformation suppression structure according to claim 1, characterized in that: The radial length of the circumferential reinforcing rib of the equivalent section of the S-bend nozzle is 25 mm to 35 mm, and the axial thickness is equal to the length of the equivalent section of the S-bend nozzle.

3. The S-bend nozzle with a deformation suppression structure according to claim 1, characterized in that: The thickness of the inner layer of the nozzle wall is 0.5mm-1.0mm, the thickness of the interlayer of the nozzle wall is 1mm-4mm, and the thickness of the outer layer of the nozzle wall is 0.5mm-1.0mm.

4. An aircraft engine, characterized in that: The high-temperature turbine outlet of the aircraft engine is equipped with an S-bend nozzle with a deformation suppression structure as described in any one of claims 1 to 3.

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