An S-shaped aerodynamic vector nozzle with a slit film cooling structure

Abstract

This invention discloses an S-bend aerodynamic vector nozzle with a slit film cooling structure, belonging to the field of aero-engines. It includes an S-bend converging section and a two-dimensional expanding section arranged axially. At least one location on the circumference of the two-dimensional expanding section is provided with a secondary flow aerodynamic vector structure with a slit film cooling structure. This secondary flow aerodynamic vector structure diverts high-pressure cold gas into the nozzle. A portion of the diverted cold gas is injected into the main flow within the nozzle from the aerodynamic vector outlet, generating a deflection force that alters the angle of the main flow. The other portion of the diverted cold gas flows out from the slit film cooling outlet located upstream of the aerodynamic vector outlet, cooling the wall surface upstream of the aerodynamic vector outlet. This invention, by incorporating a secondary flow aerodynamic vector structure with a slit film cooling structure in the nozzle expanding section, controls the deflection of the main flow and solves the problem of high-temperature combustion gas eroding the nozzle wall surface caused by the aerodynamic vector jet.

Description

Technical Field

[0001] This invention belongs to the field of aero-engines, and specifically relates to an S-curve aerodynamic vector nozzle with a slit film cooling structure. Background Technology

[0002] S-shaped nozzles can effectively reduce an aircraft's infrared and radar signatures, making them a popular choice for mission-oriented aircraft. It's worth noting that thrust vectoring technology enhances agility, post-stall maneuverability, and short takeoff and landing capabilities, partially or completely replacing aerodynamic control surfaces for flight control. It is a crucial technology for mission-oriented aircraft. Fixed-geometry aerodynamic vectoring nozzles are currently a highly sought-after exhaust system solution due to their simpler structure, lighter weight, and faster response compared to conventional mechanical thrust vectoring nozzles. New-generation mission-oriented aircraft must possess both stealth and aerodynamic vectoring capabilities, making S-shaped aerodynamic vectoring nozzles a hot research topic.

[0003] Applying aerodynamic vectoring technology to a dual-duct S-bend nozzle can cause high-temperature exhaust gases in the inner duct to flow near the nozzle wall, eroding the nozzle wall upstream of the aerodynamic vectoring outlet. Shi Jingwei's paper, "Research on the Influence of Secondary Flow Nozzle Morphology on Shock Vectoring Nozzles," indicates that for supersonic mains, the injection of secondary flow is a strong disturbance source, causing the formation of an arc-shaped induced shock wave in the mains. This induced shock wave leads to flow separation in the near-wall region, causing high-temperature exhaust gases in the inner duct to flow near the nozzle wall. The nozzle wall is prone to deformation due to the erosion caused by the high-temperature exhaust gases, and the high-temperature nozzle wall and exhaust gases can generate significant infrared radiation, affecting the stealth performance of the S-bend nozzle. Therefore, effective cooling measures are needed for S-bend aerodynamic vectoring nozzles. Summary of the Invention

[0004] The technical problem to be solved:

[0005] To overcome the shortcomings of existing technologies, this invention provides an S-curve aerodynamic vector nozzle with a slit film cooling structure. By setting a secondary flow aerodynamic vector structure with a slit film cooling structure in the nozzle expansion section, the deflection of the main flow is controlled, and the problem of high-temperature gas erosion of the nozzle wall caused by the aerodynamic vector jet is solved.

[0006] The technical solution of the present invention is: an S-bend aerodynamic vector nozzle with a slit film cooling structure, comprising an S-bend converging section and a binary expanding section arranged sequentially along the axis. At least one location on the circumference of the binary expanding section is provided with a secondary flow aerodynamic vector structure with a slit film cooling structure. The high-pressure cold air is diverted into the nozzle through the secondary flow aerodynamic vector structure. A portion of the diverted cold air is injected into the main flow of the nozzle from the aerodynamic vector outlet, which can generate a deflection force that changes the angle of the main flow. The other portion of the diverted cold air flows out from the slit film cooling outlet located upstream of the aerodynamic vector outlet, cooling the wall surface upstream of the aerodynamic vector outlet.

[0007] A further technical solution of the present invention is: the secondary flow aerodynamic vector structure with slit film cooling structure is a cold air channel located on the wall of the expansion section, with its secondary flow inlet facing outward from the wall for introducing high-pressure cold air; its outlet includes an aerodynamic vector outlet and a slit film cooling outlet disposed on the wall of the expansion section, through which the two streams of airflow diverted from the cold air channel are respectively introduced into the expansion section.

[0008] A further technical solution of the present invention is as follows: the cold air channel is a pipe that fits against the outer wall of the expansion section. The cold air in the main channel of the pipe passes through the secondary flow inlet, the secondary flow pipe, and the aerodynamic vector outlet in sequence and mixes with the main flow in the nozzle. A bypass is opened at the top of the secondary flow pipe. The bypass is a wall-fitting pipe located upstream of the secondary flow pipe and is connected to the slit film cooling outlet. The cold air diverted by the bypass passes through the secondary flow inlet, the secondary flow pipe, the wall-fitting pipe, and the slit film cooling outlet in sequence and flows into the inner wall of the expansion section upstream of the aerodynamic vector outlet.

[0009] A further technical solution of the present invention is that the injection direction of the cold air in the main channel of the pipe is perpendicular to the axial direction of the expansion section.

[0010] A further technical solution of the present invention is that the jet angle of the bypassed cold air is 50°-130°.

[0011] A further technical solution of the present invention is that the ratio of the secondary flow inlet area to the outlet area of ​​the converging section of the S-bend nozzle is 0.05-0.12.

[0012] A further technical solution of the present invention is that the ratio of the pneumatic vector outlet area to the secondary flow inlet area is 0.5-1.5.

[0013] A further technical solution of the present invention is that the ratio of the slit air film cooling outlet area to the aerodynamic vector outlet area is 0.05-0.5.

[0014] A further technical solution of the present invention is that the distance between the pneumatic vector outlet and the slit film cooling outlet is 5-10 times the width of the secondary flow pipe along the flow direction.

[0015] A further technical solution of the present invention is: two secondary flow aerodynamic vector structures with slit film cooling structures are symmetrically arranged on the upper and lower walls of the binary expansion section to control the upper and lower deflection of the main flow of the nozzle.

[0016] Beneficial effects

[0017] The beneficial effects of this invention are as follows: This invention proposes an S-bend aerodynamic vector nozzle with a slit film cooling structure, which consists of an S-bend converging section, a binary expanding section, and a secondary flow aerodynamic vector structure with a slit film cooling structure. High-pressure cold gas flows into the secondary flow aerodynamic vector structure with a slit film cooling structure through the secondary flow inlet, and most of the cold gas flows out through the aerodynamic vector outlet, thereby controlling the upward and downward deflection of the main flow; at the same time, the flow splitting design solves the problem of high-temperature gas erosion of the nozzle wall caused by the aerodynamic vector jet.

[0018] Preferably, the ratio of the secondary flow inlet area to the S-curve nozzle convergent section outlet area is controlled to be 0.05-0.12. If the secondary flow outlet area is too small, the outflow of cold air will also be small, and the angle of mainstream deflection will also be too small. However, if the secondary flow outlet area is too large, the demand for secondary flow air supply will increase, which is not conducive to the operation of the aero-engine.

[0019] Preferably, the ratio of the slit film cooling outlet area to the aerodynamic vector outlet area is 0.05-0.5. By changing the slit film cooling outlet area, the flow rate through the wall-mounted pipe is controlled, thus ensuring that a small portion of the cold air flows into the wall-mounted pipe. (The pressure of the secondary airflow needs to be adjusted according to the total inlet pressure of the main flow of the nozzle. Since the main flow has already undergone an acceleration and pressure reduction process when it reaches the secondary flow aerodynamic vector structure with the slit film cooling structure, as long as the secondary flow pressure is greater than or equal to the total inlet pressure of the nozzle, the cooling airflow can be guaranteed to flow out from the aerodynamic vector outlet and the slit film cooling outlet.) When the cold air flows in the wall-mounted pipe, it will exchange heat with the outer wall of the nozzle through convective flow, cooling the outer wall surface of the nozzle. The cold air flowing through the wall-mounted pipe flows out through the slit film cooling outlet and covers the inner wall surface upstream of the aerodynamic vector outlet, thereby reducing the temperature of the inner wall surface of the nozzle.

[0020] Preferably, the distance between the aerodynamic vectoring outlet and the slit film cooling outlet is 5-10 times the width of the secondary flow duct along the flow direction. This distance is also the area of ​​the wall surface prone to combustion gas erosion. This invention is the first to use film cooling in the field of aerodynamic vectoring technology. While satisfying the thrust vectoring characteristics of the S-bend nozzle, it reduces the temperature and infrared radiation of the nozzle wall and solves the problem of high-temperature combustion gas erosion of the nozzle wall caused by aerodynamic vectoring jets. Attached Figure Description

[0021] Figure 1This is a schematic diagram of an S-bend aerodynamic vector nozzle with a slit film cooling structure according to an embodiment of the present invention;

[0022] Figure 2 This is a partially enlarged view of the secondary flow aerodynamic vector structure with a slit film cooling structure;

[0023] Explanation of reference numerals in the attached diagram: 1. S-curve convergence section; 11. Air inlet; 2. Two-dimensional expansion section; 21. Exhaust port; 3. Secondary flow aerodynamic vector structure with slit film cooling structure; 31. Secondary flow inlet; 32. Secondary flow pipe; 33. Wall-mounted pipe; 34. Aerodynamic vector outlet; 35. Slit film cooling outlet. Detailed Implementation

[0024] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0025] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0026] Based on the existing technology, the nozzle wall is prone to deformation due to high-temperature combustion gas erosion, and the high-temperature nozzle wall and high-temperature exhaust gas can easily generate large infrared radiation, affecting the stealth performance of the S-bend nozzle. This invention provides an S-bend aerodynamic vector nozzle with a slit film cooling structure, including an S-bend converging section and a binary expanding section arranged axially in sequence. At least one location on the circumference of the binary expanding section is provided with a secondary flow aerodynamic vector structure with a slit film cooling structure. The high-pressure cold gas is diverted into the nozzle through the secondary flow aerodynamic vector structure. A portion of the diverted cold gas is injected into the main flow of the nozzle from the aerodynamic vector outlet, which can generate a deflection force that changes the angle of the main flow. The other portion of the diverted cold gas flows out from the slit film cooling outlet located upstream of the aerodynamic vector outlet, cooling the wall upstream of the aerodynamic vector outlet.

[0027] Specifically, the secondary flow aerodynamic vector structure with slit film cooling structure is a cold air channel located on the wall of the expansion section. Its secondary flow inlet faces outward from the wall and is used to introduce high-pressure cold air. Its outlet includes an aerodynamic vector outlet and a slit film cooling outlet located on the wall of the expansion section. The two airflows split by the cold air channel are introduced into the expansion section through the two outlets.

[0028] Specifically, the cold air passage is a pipe that fits against the outer wall of the expansion section. The cold air in the main passage of the pipe passes through the secondary flow inlet, the secondary flow pipe, and the aerodynamic vector outlet in sequence and mixes with the main flow in the nozzle. A bypass is opened at the top of the secondary flow pipe. The bypass is a wall-mounted pipe located upstream of the secondary flow pipe and is connected to the slit film cooling outlet. The cold air diverted by the bypass passes through the secondary flow inlet, the secondary flow pipe, the wall-mounted pipe, and the slit film cooling outlet in sequence and flows into the inner wall of the expansion section upstream of the aerodynamic vector outlet.

[0029] High-pressure cold air flows into the secondary flow aerodynamic vector structure with a slit air film cooling structure through the secondary flow inlet. Most of the cold air flows out through the aerodynamic vector outlet, thereby controlling the upward and downward deflection of the main flow. At the same time, the diversion design solves the problem of high-temperature gas erosion of the nozzle wall caused by the aerodynamic vector jet.

[0030] The above technical solution will be further explained below with reference to the accompanying drawings:

[0031] This embodiment uses an S-curve aerodynamic vector nozzle as an example to illustrate the implementation scheme of an S-curve aerodynamic vector nozzle with a slit film cooling structure. In addition to the S-curve aerodynamic vector nozzle, binary aerodynamic vector nozzles and axisymmetric aerodynamic vector nozzles can also use this slit film cooling method for cooling design, which will not be described in detail here.

[0032] Reference Figure 1 As shown, the S-curve aerodynamic vector nozzle of this embodiment includes an S-curve converging section 1 with a cross-sectional shape transitioning from circular to rectangular, and a binary expanding section 2 with a cross-sectional shape entirely rectangular. The first end of the S-curve converging section 1 has an air inlet 11 connected to the high-temperature turbine outlet of the engine. This embodiment is mainly applied to turbofan engines. The air inlet 11 is divided into a high-temperature inner inlet and a low-temperature outer bypass inlet. The low-temperature airflow in the outer bypass duct can effectively cover the nozzle wall, preventing the high-temperature airflow in the inner duct from burning the nozzle wall. The second end of the binary expanding section 2 is an exhaust port 21, and the second end of the S-curve converging section 1 is connected end-to-end to the first end of the binary expanding section 2.

[0033] Reference Figure 2The image shows a partially enlarged view of the secondary flow aerodynamic vector structure 3 with a slit film cooling structure. The secondary flow aerodynamic vector structure 3 consists of a secondary flow inlet 31, a secondary flow pipe 32, a wall-mounted pipe 33, an aerodynamic vector outlet 34, and a slit film cooling outlet 35, and is disposed on the upper or lower wall surface of the binary expansion section 2. The secondary flow pipe 32 and the wall-mounted pipe 33 are rectangular pipes. The reference injection angle of the secondary flow pipe 32 is 90°, which is the angle between the cross-section of the secondary flow pipe and the cross-section of the nozzle. The range of the secondary flow injection angle is 50°-130°. The wall-mounted pipe 33 is parallel to the nozzle wall surface, and the secondary flow pipe 32 is connected to the wall-mounted pipe 33. The pneumatic vector outlet 34 is located downstream of the slit film cooling outlet 35. High-pressure cold air flows into the secondary flow jet structure 3 with the slit film cooling structure through the secondary flow inlet 31. Most of the cold air flows out through the pneumatic vector outlet 34, thereby controlling the upward and downward deflection of the main flow. A small portion of the cold air flows into the wall-mounted pipe 33 and flows out through the slit film cooling outlet 35, cooling the wall upstream of the pneumatic vector outlet 34, thereby solving the problem of high-temperature gas erosion of the nozzle wall caused by the pneumatic vector jet.

[0034] Specifically, the ratio of the area of ​​the secondary flow inlet 31 to the outlet area of ​​the S-bend nozzle convergent section 1 is 0.05-0.12; the ratio of the area of ​​the aerodynamic vector outlet 34 to the area of ​​the secondary flow inlet 31 is 0.5-1.5; the ratio of the area of ​​the slit film cooling outlet 35 to the area of ​​the aerodynamic vector outlet 34 is 0.05-0.5; and the distance between the aerodynamic vector outlet 34 and the slit film cooling outlet 35 is 5-10 times the width of the secondary flow pipe 32 along the flow direction.

[0035] In this embodiment, the high-pressure cold air flows into the secondary flow aerodynamic vector structure 3 with a slit film cooling structure through the secondary flow inlet 31. Most of the cold air flows out through the aerodynamic vector outlet 34, thereby controlling the upward and downward deflection of the main flow. A small portion of the cold air flows into the wall-mounted pipe 33. When the cold air flows in the wall-mounted pipe, it will exchange heat with the outer wall of the nozzle through convective flow, cooling the outer wall of the nozzle. The cold air flowing through the wall-mounted pipe 33 flows out through the slit film cooling outlet 35 and covers the inner wall upstream of the aerodynamic vector outlet 34, thereby reducing the temperature of the inner wall of the nozzle, reducing the infrared radiation of the S-bend aerodynamic vector nozzle, and solving the problem of high-temperature gas erosion of the nozzle wall caused by the aerodynamic vector jet.

[0036] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. An S-bend aerodynamic vector nozzle with a slit film cooling structure, comprising an S-bend converging section and a binary expanding section arranged sequentially along the axis, characterized in that: At least one location on the circumference of the binary expansion section is provided with a secondary flow aerodynamic vector structure with a slit film cooling structure. The high-pressure cold air is diverted into the nozzle through the secondary flow aerodynamic vector structure. A portion of the diverted cold air is injected into the main flow in the nozzle from the aerodynamic vector outlet, which can generate a deflection force that changes the angle of the main flow. The other portion of the diverted cold air flows out from the slit film cooling outlet located upstream of the aerodynamic vector outlet, which cools the wall upstream of the aerodynamic vector outlet. The secondary flow aerodynamic vector structure with slit film cooling structure is a cold air channel located on the wall of the expansion section, with its secondary flow inlet facing outwards from the wall, used to introduce high-pressure cold air. Its outlets include an aerodynamic vector outlet and a slit film cooling outlet located on the wall of the expansion section. The two airflows that are split from the cold air passage are introduced into the expansion section through the two outlets. The cold air passage is a pipe that fits against the outer wall of the expansion section. The cold air in the main passage of the pipe passes through the secondary flow inlet, the secondary flow pipe, and the aerodynamic vector outlet in sequence and mixes with the main flow in the nozzle. A bypass is opened at the top of the secondary flow pipe. The bypass is a wall-mounted pipe located upstream of the secondary flow pipe and is connected to the slit film cooling outlet. The cold air diverted by the bypass passes through the secondary flow inlet, the secondary flow pipe, the wall-mounted pipe, and the slit film cooling outlet in sequence and flows into the inner wall of the expansion section upstream of the aerodynamic vector outlet.

2. The S-bend aerodynamic vector nozzle with a slit film cooling structure according to claim 1, characterized in that: The direction of the cold air jet in the main channel of the pipeline is perpendicular to the axial direction of the expansion section.

3. The S-bend aerodynamic vector nozzle with a slit film cooling structure according to claim 2, characterized in that: The jet angle of the bypassed cold air is 50°-130°.

4. An S-bend aerodynamic vector nozzle with a slit film cooling structure according to any one of claims 1-3, characterized in that: The ratio of the secondary flow inlet area to the outlet area of ​​the converging section of the S-bend nozzle is 0.05-0.

12.

5. The S-bend aerodynamic vector nozzle with a slit film cooling structure according to claim 4, characterized in that: The ratio of the pneumatic vector outlet area to the secondary flow inlet area is 0.5-1.

5.

6. The S-bend aerodynamic vector nozzle with a slit film cooling structure according to claim 5, characterized in that: The ratio of the slit film cooling outlet area to the aerodynamic vector outlet area is 0.05-0.

5.

7. The S-bend aerodynamic vector nozzle with a slit film cooling structure according to claim 6, characterized in that: The distance between the pneumatic vector outlet and the slit film cooling outlet is 5-10 times the width of the secondary flow pipe along the flow direction.

8. The S-bend aerodynamic vector nozzle with a slit film cooling structure according to claim 7, characterized in that: The upper and lower walls of the binary expansion section are symmetrically provided with two secondary flow aerodynamic vector structures with slit film cooling structures, which are used to control the upward and downward deflection of the main flow of the nozzle.

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