An adjustable pressure reduction device for the cooling air channel of an aircraft engine tail nozzle

Abstract

The present invention provides an adjustable pressure-reducing device for the cold air passage of an aircraft engine tail nozzle with a heat shield, belonging to the field of aircraft engine thermal management technology. The device includes a tail nozzle and an adjustable pressure-reducing device. The tail nozzle includes an adjusting plate and a heat shield. The heat shield is arranged on the inner side of the adjusting plate and forms a cold air passage with the outer wall; the adjustable pressure-reducing device is a cam structure, arranged between the outer wall and the heat shield. The present invention mainly utilizes a cam pressure-reducing structure arranged in the cold air cavity of the tail nozzle to effectively reduce the pressure of the cold air, thereby reducing the tail nozzle's demand for cold air while improving the cooling effect, and can achieve the function of timely matching the pressure drop degree of the cold air passage with the mainstream pressure drop under different working conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of aero-engine thermal management, and relates to an adjustable pressure reduction device for a cold air channel of an aero-engine tail nozzle with a heat shield. Background Art

[0002] As supersonic aircraft engine thrust performance increases, the temperature of the mainstream gas passing through the tailpipe is also increasing, posing a significant threat to the nozzle's convergence and divergence flaps and their control systems. A heat shield with cooling air holes is used in the tailpipe to form a cooling air channel with the nozzle's convergence and divergence flaps. This cooling air channel and heat shield isolate the nozzle's convergence and divergence flaps and their control systems from the high-temperature mainstream gas, effectively protecting them.

[0003] The mainstream combustion gas of a supersonic aircraft engine's tail nozzle reaches the speed of sound when passing through the throat and enters supersonic speed in the expansion section. The pressure of the mainstream combustion gas drops significantly, while the high pressure state in the cooling air duct remains basically unchanged. This causes the pressure difference in the expansion section through the cooling air holes of the heat shield to be too large. As a result, the expansion section uses too much cooling air due to the high pressure difference between the cooling air duct and the mainstream combustion gas, and at the same time, it strongly disturbs the mainstream, affecting the thrust performance. Currently, there is usually no pressure reduction device in the cooling air duct or an unadjustable labyrinth-type pressure reduction device. The labyrinth-type pressure reduction device is too complex and poses a challenge to the weight reduction design of the overall structure. In addition, the structure is not adjustable and does not have the function of timely matching the pressure reduction degree of the cooling air duct with the mainstream pressure drop under different flight conditions.

[0004] In order to match the pressure drop degree of the nozzle cooling channel with the rapid pressure reduction of the mainstream expansion section, the present invention designs an adjustable pressure reduction device for the cooling channel of the tail nozzle of an aircraft engine with a heat shield. Summary of the Invention

[0005] In view of the existing thermal protection technology for aircraft engine tail nozzles, the present invention makes the following designs in terms of structure and function, providing an adjustable pressure reduction device for the cold air channel of an aircraft engine tail nozzle with a heat shield.

[0006] The technical solution adopted in the present invention is:

[0007] The invention discloses an adjustable pressure reducing device for a cold air passage of an aircraft engine tail nozzle with a heat insulation screen. The adjustable pressure reducing device comprises a tail nozzle I and an adjustable pressure reducing device II.

[0008] The tail nozzle I includes a heat shield 6 and an adjustment plate 7, which are fixedly connected by screws. The heat shield 6 is positioned inside the adjustment plate 7, forming a cold air passage between the heat shield 6 and the adjustment plate 7. The adjustment plate 7 is connected to an actuator outside the entire adjustable pressure reduction device, which drives the adjustment plate 7.

[0009] The adjustable pressure reduction device II is arranged in the tail nozzle I and includes a cam throttling structure 1, a flow hole 2, a bearing structure 3, a rotating shaft 4, and an actuating rod 5. The main body of the adjustable pressure reduction device is the cam throttling structure 1, which is arranged in the cold air flow channel between the adjusting plate 7 and the heat shield 6. The flow holes 2 are arranged in a cross-row on both sides of the cam throttling structure 1. The two ends of the cam throttling structure 1 are fixed to the bearing structure 3. The two bearing structures 3 are mounted on the inner surface of the adjusting plate 7. The bearing structure 3 is also connected to the rotating shaft 4 and can rotate when subjected to force. The bearing structure 3 drives the cam throttling structure 1 to move synchronously. One end of the actuating rod 5 is fixed to the bearing structure 3, and the other end is connected to an external actuator. The actuator drives the actuating rod 5 to move, and the cam throttling structure 1 is linked through the actuating rod 5.

[0010] The cam throttling structure 1 is rotated to different angles by the actuator rod 5, thereby controlling the change in the cross-sectional area of the flow channel, that is, controlling the flow area of the cold air channel, achieving the effect of throttling and reducing pressure, and realizing the rapid matching of the cold air channel pressure and the mainstream pressure under different working conditions; at the same time, the rotation angle can be adjusted synchronously with the movement angle of the adjustment plate 7, so that the degree of pressure reduction in the cold air channel can be matched quickly and timely with the mainstream pressure drop under different working conditions.

[0011] Furthermore, the cam throttling structure 1 is hollow, with a tapered vertical cross-section, increasing in size from the end closest to the heat shield 6 toward the regulating plate 7. Multiple through-holes 2 are spaced apart on both sides, and the through-holes 2 are arranged in a cross-pattern. This allows the cross-sectional area of the flow channel to be controlled by rotating it at different angles, achieving a throttling and pressure-reducing effect. The rotation angle can be adjusted accordingly with the movement angle of the regulating plate, ensuring that the degree of pressure reduction in the cold air channel matches the mainstream pressure drop under different operating conditions.

[0012] Furthermore, the height of the cold air flow duct inlet is 15-20 mm.

[0013] Furthermore, the vertical height of the cam throttling structure 1 is 12-18 mm, the maximum width is 2-6 mm, the throttling area in the maximum throttling state is 1 / 2 to 3 / 4 of the flow area; the throttling area in the minimum throttling state is 1 / 8 to 1 / 4 of the flow area.

[0014] The beneficial effects of the present invention are as follows: 1) the present invention realizes the throttling and pressure reduction effect of the cold air in the cold air channel of the tail nozzle of an aircraft engine; 2) the cam throttling structure and the linkage device are used to realize the function of synchronously adjusting the cross-sectional area of the cold air flow channel with the deflection of the adjustment plate, thereby achieving the effect of quickly matching the degree of pressure change in the cold air channel with the degree of pressure change in the mainstream; 3) the pressure reduction device designed in the present invention is conducive to realizing the lightweight design of the tail nozzle of an aircraft engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The figure is a schematic diagram of the tail nozzle cooler channel with adjustable pressure reduction;

[0016] Figure 2 Different throttling states for the adjustable pressure reducing device;

[0017] Figure 3 The pressure reduction effect of the adjustable pressure reduction device under ground test bench conditions and supersonic cruise conditions;

[0018] In the figure: 1 cam throttling structure; 2 flow hole; 3 bearing structure; 4 rotating shaft; 5 actuator rod; 6 heat shield; 7 adjustment plate. DETAILED DESCRIPTION

[0019] The present invention will be described in detail with reference to the accompanying drawings.

[0020] The main structural parts of the present invention are introduced.

[0021] The invention discloses an adjustable pressure reducing device for a cold air passage of an aircraft engine tail nozzle with a heat insulation screen. The adjustable pressure reducing device comprises a tail nozzle I and an adjustable pressure reducing device II.

[0022] The tail nozzle I includes a heat shield 6 and an adjustment plate 7, which are fixedly connected by screws. The heat shield 6 is positioned inside the adjustment plate 7, forming a cold air passage between the heat shield 6 and the adjustment plate 7. The adjustment plate 7 is connected to an actuator outside the entire adjustable pressure reduction device, which drives the adjustment plate 7.

[0023] The adjustable pressure reduction device II is arranged in the tail nozzle I and includes a cam throttling structure 1, a flow hole 2, a bearing structure 3, a rotating shaft 4, and an actuating rod 5. The main body of the adjustable pressure reduction device is the cam throttling structure 1, which is arranged in the cold air flow channel between the adjusting plate 7 and the heat shield 6. The flow holes 2 are arranged in a cross-row on both sides of the cam throttling structure 1. The two ends of the cam throttling structure 1 are fixed to the bearing structure 3. The two bearing structures 3 are mounted on the inner surface of the adjusting plate 7. The bearing structure 3 is also connected to the rotating shaft 4 and can rotate when subjected to force. The bearing structure 3 drives the cam throttling structure 1 to move synchronously. One end of the actuating rod 5 is fixed to the bearing structure 3, and the other end is connected to an external actuator. The actuator drives the actuating rod 5 to move, and the cam throttling structure 1 is linked through the actuating rod 5.

[0024] The cam throttling structure 1 is rotated to different angles by the actuator rod 5, thereby controlling the change in the cross-sectional area of the flow channel, that is, controlling the flow area of the cold air channel, achieving the effect of throttling and reducing pressure, and realizing the rapid matching of the cold air channel pressure and the mainstream pressure under different working conditions; at the same time, the rotation angle can be adjusted synchronously with the movement angle of the adjustment plate 7, so that the degree of pressure reduction in the cold air channel can be matched quickly and timely with the mainstream pressure drop under different working conditions.

[0025] In this embodiment, the cam throttling structure 1 is a hollow structure, and its vertical cross-section is a conical structure, and its size increases from the end close to the heat insulation screen 6 to the direction close to the adjustment plate 7; multiple flow holes 2 are provided at intervals on both side surfaces, and the flow holes 2 on both side surfaces are cross-arranged.

[0026] In this embodiment, the height of the cold air flow duct inlet is 20 mm.

[0027] In this embodiment, the vertical height of the cam throttling structure 1 is 15 mm, the maximum width is 6 mm, the throttling area in the maximum throttling state is 3 / 4 of the flow area; the throttling area in the minimum throttling state is 1 / 4 of the flow area.

[0028] To adapt to the aircraft's varying operating conditions and achieve the highest possible thrust coefficient and lowest specific fuel consumption, the tail nozzle's throat and exit areas change via the movement of a regulating vane 7. When the expansion angle of regulating vane 7 increases or decreases, the cam throttling mechanism rotates a certain angle accordingly, increasing or decreasing the cold air duct flow area. When the pitch angle changes, this pressure-reducing structure synchronizes the cam throttling mechanism 1 with the regulating vane 7 via a linkage 5. When the expansion angle of regulating vane 7 increases or decreases, the cam throttling mechanism 1 rotates a certain angle accordingly, increasing or decreasing the cold air duct flow area. When the pitch angle reaches its maximum, the cam throttling mechanism 1 switches to its minimum throttling state to accommodate changes in the mainstream flow rate. When the pitch angle reaches its minimum, the cam throttling mechanism 1 switches to its maximum throttling state to achieve optimal pressure reduction on the cold air side, thereby quickly matching the pressure changes in the cold air duct with those in the mainstream.

[0029] The above-described embodiments merely express the implementation methods of the present invention, but should not be understood as limiting the scope of the patent of the present invention. It should be pointed out that for those skilled in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. An adjustable pressure reducing device for the cooling air channel of an aircraft engine tail nozzle with a heat shield, characterized in that: The adjustable pressure reduction device comprises: a tail nozzle (I) and an adjustable pressure reduction device (II); The tail nozzle (I) includes a heat shield (6) and an adjustment plate (7). The heat shield (6) is arranged on the inner side of the adjustment plate (7) to form a cold air channel with the adjustment plate (7); the adjustment plate (7) is connected to an external actuator; the adjustable pressure reduction device (II) is arranged in the tail nozzle (I), and its main body is a cam throttling structure (1). The cam throttling structure (1) can control the change of the flow channel cross-sectional area by rotating at different angles, thereby achieving the effect of throttling and reducing pressure, and realizing the rapid matching of the cold air channel pressure and the mainstream pressure under different working conditions; at the same time, the rotation angle can be adjusted synchronously with the movement angle of the adjustment plate (7), so that the pressure reduction degree of the cold air channel is promptly and quickly matched with the mainstream pressure drop under different working conditions; The adjustable pressure reduction device (II) comprises a cam throttling structure (1), a flow hole (2), a bearing structure (3), a rotating shaft (4), and an actuating rod (5); the cam throttling structure (1) is arranged in a cold air flow channel, and the flow holes (2) are arranged in a cross-row on both sides of the cam throttling structure (1); both ends of the cam throttling structure (1) are fixed on the bearing structure (3), and the two bearing structures (3) are installed on the inner surface of the regulating plate (7); the bearing structure (3) is also connected to the rotating shaft (4), and can be rotated when subjected to force, and the bearing structure (3) drives the cam throttling structure (1) to move synchronously; one end of the actuating rod (5) is fixed on the bearing structure (3), and the other end is connected to an external actuator, and the actuator drives the actuating rod (5) to move, and the cam throttling structure (1) is linked through the actuating rod (5).

2. The adjustable pressure reducing device for the cooling air passage of the tail nozzle of an aircraft engine with a heat shield according to claim 1, characterized in that: The cam throttling structure (1) is a hollow structure, and its vertical cross-section is a conical structure, and its size increases from the end close to the heat insulation screen (6) to the direction close to the adjustment plate (7); a plurality of flow holes (2) are provided at intervals on both side surfaces, and the flow holes (2) on the two side surfaces are cross-arranged.

3. The adjustable pressure reducing device for the cooling air channel of the tail nozzle of an aircraft engine with a heat shield according to claim 2, characterized in that: The vertical height of the cam throttling structure (1) is 12-18 mm, the maximum width is 2-6 mm, the throttling area in the maximum throttling state is 1 / 2 to 3 / 4 of the flow area; the throttling area in the minimum throttling state is 1 / 8 to 1 / 4 of the flow area.

4. The adjustable pressure reducing device for the cooling air passage of the tail nozzle of an aircraft engine with a heat shield according to claim 1, characterized in that: The height of the cold air flow duct inlet is 15-20 mm.

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