Aero-engine nozzle with adjustable detectability

Abstract

The invention belongs to the technical field of aero-engine structural design, and relates to a detectability-adjustable aero-engine jet pipe. The core of the spray pipe is a deformable structure, and the spray pipe mainly comprises a round-to-square section, an adjusting sheet, an arc-shaped throat plate, a single-side expansion section and an actuating mechanism. The arc-shaped throat plate is driven by the actuating cylinder to move up and down in the side wall track, the adjusting piece is driven to move, and therefore the spraying pipe structure is intelligently switched, the low detectability mode is formed through upward movement, and full shielding is achieved through the single-side expansion section; and the high-thrust mode is started when the cylinder moves downwards. Meanwhile, the spray pipe is integrated with a two-way cooling system, one way provides long-time basic cooling, and the other way can spray ultralow-temperature media for a short time to conduct active strong cooling. The engine can meet the anti-detection requirement and the requirement of the stress application state for flame propagation and stability.

Description

Technical Field

[0001] This application belongs to the field of aero-engine structural design technology, specifically relating to an aero-engine nozzle with adjustable detectability. Background Technology

[0002] With the continuous advancement of aerospace detection technology, the management of aircraft detectability in complex airspace environments has become a key area of ​​cutting-edge research. The nozzle system of an aero-engine, as a critical channel for the exhaust of high-temperature exhaust gases, generates significant electromagnetic wave scattering characteristics and infrared radiation features, which are among the main factors affecting the backward signal characteristics of an aircraft. Therefore, developing advanced nozzle technology to effectively manage these signal characteristics is of great significance for improving the overall performance of aircraft.

[0003] Currently, the design of aero-engine nozzles faces an inherent contradiction between the requirements for high-performance aerodynamics and low observability. High-performance aero-engines pursue high thrust-to-weight ratios and high efficiency, which requires nozzles to have unobstructed flow paths and optimized area adjustment capabilities at full power (afterburner) to maximize thrust output. However, from the perspective of low observability, it is necessary to optimize signal characteristics through methods such as "geometry shaping" and "thermal management," which often requires changing or even constraining the shape of the flow path, potentially interfering with airflow and causing performance losses. How to achieve low observability without sacrificing core aerodynamic performance is an extremely challenging design problem.

[0004] Existing technologies for achieving low detectability of nozzles have certain limitations. One is the traditional mechanically adjustable nozzle technology. The core design of this type of nozzle relies on the movement of movable adjusting vanes to change the throat area, adapting to the aerodynamic requirements of the engine under different operating conditions. However, its adjustment modes are entirely geared towards aerodynamic performance, and low detectability is not a design goal for its configuration variations. Therefore, its structure cannot effectively shield high-temperature components in front, and its potential for reducing electromagnetic wave and infrared signature is limited.

[0005] Secondly, there is the technology of fixed special-configuration nozzles, such as nozzles with curved flow channels or non-axisymmetric cross-sections. These designs, through their inherent geometry, can physically shield the internal high-temperature regions using the nozzle walls, thus optimizing signal characteristics to some extent. However, these nozzles are typically fixed in configuration and lack the ability to adjust the throat area. When an aircraft needs to engage the afterburner to obtain maximum thrust, the fixed, complex flow channel shape will restrict exhaust efficiency, leading to a significant loss of thrust performance and making it difficult to meet the stringent power response requirements of highly maneuverable flight platforms. Therefore, they are commonly found in applications where the thrust variation range is not critical.

[0006] Thirdly, in terms of thermal management technology, existing nozzles mostly rely on continuous wall cooling from the engine's bypass duct or the airframe's bleed air. This long-term, stable cooling method is effective in maintaining component temperatures and achieving basic infrared signal control. However, in specific high-requirement scenarios where aircraft need to drastically change signal characteristics, such as in densely monitored airspace or when emergency adjustments to flight status are required, the cooling intensity and response speed of existing technologies are insufficient to achieve rapid and active suppression of signal characteristics, resulting in a bottleneck in performance improvement.

[0007] In summary, current technologies lack a comprehensive nozzle solution capable of intelligently adapting to the demands of various flight missions. Particularly in high-performance afterburning engines, there is an urgent need for an advanced nozzle capable of dynamically adjusting its configuration and flexibly switching between "high aerodynamic performance mode" and "low observability mode." Such a nozzle not only needs to solve the integrated design challenges of variable structure and signal characteristic control, but also needs to integrate highly reliable adjustment mechanisms, effective sealing, and a multi-stage thermal management system within a compact space. This will truly achieve synergistic optimization of aerodynamic performance and low observability, enhancing the overall technological competitiveness of the aircraft. Summary of the Invention

[0008] To address the aforementioned issues, this application provides a detectable adjustable aero-engine nozzle, primarily comprising a square section connected to the nozzle's circular outlet via a circular-to-square section. The square section includes an upper outer cover, a lower outer cover, and a sidewall. An adjustment plate is provided between the upper and lower outer covers. The adjustment plate includes a first adjustment plate, a second adjustment plate, and a single-sided expansion section. The first and second adjustment plates are slidably disposed within the track groove of an arc-shaped throat plate. The other end of the first adjustment plate is hinged to the circular-to-square section, and the other end of the second adjustment plate is hinged to the single-sided expansion section. The other end of the single-sided expansion section is connected to the end of the lower outer cover. The arc-shaped throat plate is mounted on a track located on the sidewall via a side shaft and is driven to move up and down by an actuator to control the throat distance between the adjustment plate and the upper outer cover.

[0009] A gas-containing space is formed between the regulating plate and the lower outer cover. Gas drawn from the engine duct or engine compartment enters the gas-containing space through the first injection rod. Cooling medium drawn from the ultra-low temperature cold source enters the gas-containing space as needed through the second injection rod. At least one gas film hole is provided on the single-sided expansion section of the regulating plate to introduce the gas in the gas-containing space into the inner wall of the square section to form a cooling gas film.

[0010] Preferably, the arc surface of the arc-shaped throat plate has a track groove, and the tenons of the first adjusting plate and the second adjusting plate are installed at both ends of the track groove through tenon grooves.

[0011] Preferably, the inner side of the upper outer cover is also provided with an upper converging plate that shrinks the vertical distance between the square segments and an upper expanding plate that expands the vertical distance between the square segments. The upper converging plate and the upper expanding plate are connected at the hinge end of the second adjusting plate and the single-sided expanding segment.

[0012] Preferably, the second adjusting plate, the upper expanding plate, the side wall, and the arc-shaped throat plate are all provided with air film holes.

[0013] Preferably, the cryogenic cold source is liquid nitrogen.

[0014] Preferably, in an emergency evasive maneuver, the second injection bar is briefly opened to rapidly cool the nozzle using a cooling medium.

[0015] This application achieves intelligent switching between high aerodynamic performance and low detectability through a deformable nozzle structure, and innovatively integrates long-term and short-term active cooling technologies, ultimately achieving comprehensive management of ultra-high performance signal characteristics. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the nozzle in a fully obscured state according to a preferred embodiment of the detectability-adjustable aero-engine nozzle of this application.

[0017] Figure 2 This application Figure 1 A schematic diagram of the nozzle in full afterburner and high thrust state in the embodiment shown.

[0018] Figure 3 This application Figure 1 Rear view of the nozzle in the fully obscured state of the embodiment shown.

[0019] Figure 4 This is a top view of the single-sided expansion segment structure.

[0020] Figure 5 This is a schematic diagram showing the connection between the adjusting plate and the arc-shaped throat plate.

[0021] Figure 6 This is a schematic diagram of an arc-shaped throat plate structure.

[0022] Figure 7 This is a schematic diagram of the first adjusting plate.

[0023] Figure 8 This is a schematic diagram of the second adjusting plate.

[0024] Among them, 1-round to square section, 2-first adjusting plate, 3-arc throat plate, 4-track, 5-second adjusting plate, 6-upper converging plate, 7-upper expanding plate, 8-single-sided expansion section, 9-side wall, 10-upper outer cover, 11-lower outer cover, 13-side wall cover plate, 14-first spray rod, 15-second spray rod. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0026] This application provides a detectability-adjustable aero-engine nozzle, such as... Figures 1-8 As shown, it mainly includes a square section connected to the circular outlet of the nozzle via a circular-to-square section 1. The square section includes an upper outer cover 10, a lower outer cover 11, and a side wall 9. The feature is that an adjustment plate is provided between the upper outer cover 10 and the lower outer cover 11. The adjustment plate includes a first adjustment piece 2, a second adjustment piece 5, and a single-sided expansion section 8. The first adjustment piece 2 and the second adjustment piece 5 are respectively slidably disposed in the track groove of the arc-shaped throat plate 3. The other end of the first adjustment piece 2 is hinged to the circular-to-square section 1, and the other end of the second adjustment piece 5 is hinged to the single-sided expansion section 8. The other end of the single-sided expansion section 8 is connected to the end of the lower outer cover 11. The arc-shaped throat plate 3 is installed in the track 4 located on the side wall 9 via a side shaft, and the arc-shaped throat plate 3 is driven to move up and down by an actuating cylinder to control the throat distance between the adjustment plate and the upper outer cover 10.

[0027] A gas-containing space is formed between the regulating plate and the lower outer cover 11. Gas drawn from the engine duct or engine compartment enters the gas-containing space through the first injection rod 14. Cooling medium drawn from the ultra-low temperature cold source enters the gas-containing space as needed through the second injection rod 15. At least one gas film hole is provided on the single-sided expansion section 8 of the regulating plate to introduce the gas in the gas-containing space into the inner wall of the square section to form a cooling gas film.

[0028] This application uses an actuator to drive the arc-shaped throat plate 3 to move up and down within the track 4, which in turn causes the first adjusting plate 2 and the second adjusting plate 5 to move, thereby changing the shape of the nozzle flow channel. When the arc-shaped throat plate 3 moves upward, the adjusting plate bulges out, forming a shape like... Figure 1 The nozzle structure shown has a second adjusting vane 5 that effectively shields high-temperature components in the rear-view direction, significantly reducing radar cross-section (RCS) and infrared radiation. When the arc-shaped throat plate 3 moves downward, the adjusting vane sinks, forming a... Figure 2In the full afterburner mode shown, the nozzle opens up a larger flow area to meet the high thrust requirements.

[0029] Secondly, at least one gas film oblique hole is distributed on the single-sided expansion section 8 to utilize the external bypass gas or the gas inside the engine compartment for cooling along the way; the top of the arc-shaped throat plate 3 is ensured to be higher than the upper edge of the track 4 during the movement to ensure sealing; the first injection rod 14 injects cooling gas B into the gas containing space. Cooling gas B is the gas inside the engine compartment, which overflows from the gas film hole on the single-sided expansion section 8 and is supplied for a long time to form long-term gas film cooling; the second injection rod 15 injects ultra-low temperature cooling medium A into the containing space, which overflows from the gas film hole on the single-sided expansion section 8 and is supplied for a short time as needed to form short-term gas film cooling.

[0030] The single-sided expansion nozzle provided in this application shields the detection area below the nozzle based on the single-sided expansion section. Simultaneously, the adjusting plate physically shields the hot-end components at the front end of the nozzle, reducing the contribution of solid-state infrared radiation and electromagnetic scattering signals. Furthermore, the nozzle exit design of this application features serrations. These serrations enhance the mixing of the high-temperature mainstream with the ambient air, reducing the core flow temperature and decreasing the contribution of infrared signals. The diffraction effect at the serrated edges also weakens the intensity of electromagnetic wave reflection, reducing radar detectability.

[0031] In some alternative embodiments, the arc surface of the arc-shaped throat plate 3 has a track groove, and the tenons of the first adjusting plate 2 and the second adjusting plate 5 are installed at both ends of the track groove through tenon grooves.

[0032] like Figures 5-8 As shown, the sliding connection mechanism is achieved through the cooperation of tenons and mortises. Specifically, one end of the first adjusting plate 2 and the second adjusting plate 5 is provided with tenons (C and E), respectively, while the arc-shaped throat plate 3 has a matching mortise D. This design allows the tenons of the adjusting plates to slide smoothly against the wall on the arc surface of the mortise when the adjusting plates move with the throat plate, while reliably constraining the adjusting plates to the throat plate, ensuring structural stability and sealing during movement. This connection method has a compact structure and is very suitable for arrangement in the narrow space of high temperature and high vibration inside the nozzle. It provides a stable and reliable kinematic pair, ensuring precise control of the nozzle profile during deformation, and is a key basic structure for realizing adjustable functions.

[0033] In some alternative embodiments, the inner side of the upper outer cover 10 is also provided with an upper converging plate 6 that shrinks the vertical spacing of the square segment and an upper expanding plate 7 that expands the vertical spacing of the square segment. The upper converging plate 6 and the upper expanding plate 7 are directly opposite the hinge end of the second adjusting plate 5 and the single-sided expansion segment 8 at the connection point.

[0034] like Figure 1As shown, the upper converging plate 6 and the upper expanding plate 7 on the inner side of the upper outer cover 10 constitute the profile of the upper wall of the nozzle. This profile, together with the adjustable regulating plate, forms a complete flow channel. This structural design ensures a smooth transition of the flow channel profile, which is beneficial for maintaining aerodynamic performance.

[0035] In some alternative embodiments, air film holes are provided on the second adjusting plate 5, the upper expanding plate 7, the side wall 9, and the arc-shaped throat plate 3.

[0036] In this embodiment, the second adjusting plate 5, the upper expanding plate 7, the side wall 9, and the arc-shaped throat plate 3 are also provided with air film holes, wherein, for example Figure 3 As shown, a side wall cover plate 13 is installed on the outer side of the side wall 9, forming an airflow channel between the two and connecting to the outer bypass. The cooling air of the outer bypass is introduced into the inner wall surface of the side wall through the air film hole. The structure and principle of the upper expansion plate 7 are the same as those of the side wall 9. The second adjustment plate 5 and the arc-shaped throat plate 3 are similar to the single-sided expansion section 8. They can introduce the cooling air of the gas containing space to the structural surface and introduce the ultra-low temperature cooling medium of the gas containing space to the structural surface.

[0037] In some alternative implementations, the cryogenic cold source is liquid nitrogen.

[0038] In some alternative implementations, in an emergency evasive maneuver, the second injection rod 15 is briefly opened to rapidly cool the nozzle using a cooling medium.

[0039] In this embodiment, the present application can actively activate the high-performance mode, and the second jet rod 15 sprays liquid nitrogen or other cryogenic cooling medium A into the gas containing space. The liquid nitrogen overflows from the air film holes on the arc-shaped throat plate 3, the second adjusting plate 5, and the single-sided expansion section 8, forming a short-term high-efficiency air film cooling, which improves the survivability of the aircraft in the face of new infrared detection. When the aircraft is flying at high speed with afterburner, when the arc-shaped throat plate 3 is driven to the bottom of the track 4, the full afterburner high thrust mode is activated. At this time, the second jet rod 15 is in the jet-off state.

[0040] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A detectable adjustable aero-engine nozzle, comprising a square segment connected to the circular nozzle outlet via a circular-to-square section (1), said square segment comprising an upper outer cover (10), a lower outer cover (11), and a sidewall (9), characterized in that, An adjustment plate is provided between the upper outer cover (10) and the lower outer cover (11). The adjustment plate includes a first adjustment piece (2), a second adjustment piece (5), and a single-sided expansion section (8). The first adjustment piece (2) and the second adjustment piece (5) are respectively slidably disposed in the track groove of the arc-shaped throat plate (3). The other end of the first adjustment piece (2) is hinged to the round-to-square section (1), and the other end of the second adjustment piece (5) is hinged to the single-sided expansion section (8). The other end of the single-sided expansion section (8) is connected to the end of the lower outer cover (11). The arc-shaped throat plate (3) is installed in the track (4) located on the side wall (9) through the side shaft, and the arc-shaped throat plate (3) is driven to move up and down by the actuator to control the throat distance between the adjustment plate and the upper outer cover (10). A gas containment space is formed between the regulating plate and the lower outer cover (11). Gas drawn from the engine duct or engine compartment enters the gas containment space through the first injection rod (14). Cooling medium drawn from the ultra-low temperature cold source enters the gas containment space as needed through the second injection rod (15). At least one gas film hole is provided on the single-sided expansion section (8) of the regulating plate to introduce the gas in the gas containment space into the inner wall of the square section to form a cooling gas film.

2. The detectability-adjustable aero-engine nozzle according to claim 1, characterized in that, The arc surface of the arc-shaped throat plate (3) has a track groove, and the tenons of the first adjusting plate (2) and the second adjusting plate (5) are installed at both ends of the track groove through tenon grooves.

3. The detectability-adjustable aero-engine nozzle according to claim 1, characterized in that, The inner side of the upper outer cover (10) is also provided with an upper converging plate (6) that shrinks the vertical distance between the square segments and an upper expanding plate (7) that expands the vertical distance between the square segments. The upper converging plate (6) and the upper expanding plate (7) are connected to the hinge end of the second adjusting plate (5) and the single-sided expanding segment (8).

4. The detectability-adjustable aero-engine nozzle according to claim 3, characterized in that, Air film holes are provided on the second adjustment plate (5), the upper expansion plate (7), the side wall (9) and the arc-shaped throat plate (3).

5. The detectability-adjustable aero-engine nozzle according to claim 1, characterized in that, The cryogenic cold source is liquid nitrogen.

6. The detectability-adjustable aero-engine nozzle according to claim 1, characterized in that, In an emergency evasive maneuver, the second injection bar (15) is briefly opened to rapidly cool the nozzle using a cooling medium.

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