Miniature supersonic nozzle array apparatus and engine for intake augmentation

Abstract

This invention relates to the field of supersonic inlet start-up and active flow control technology, aiming to solve the problems of inlet flow separation, shock wave boundary layer interference, and start-up lag in existing scramjet engines. It provides a miniature supersonic nozzle array device and engine for enhancing inlet start-up. The miniature supersonic nozzle array device includes a rotating mechanism on which multiple nozzles are mounted, arranged at intervals. The airflow channel inside each nozzle is an acceleration channel, and the airflow channel between two adjacent nozzles is a deceleration channel. The acceleration channel is sequentially divided into an acceleration channel inlet section, a central contraction section, and an acceleration channel outlet section along the gas flow direction. The cross-sectional size of the central contraction section is smaller than that of the acceleration channel inlet section and the acceleration channel outlet section. This invention effectively solves the problems of shock wave boundary layer interference, flow separation, and start-up lag at the inlet lip under high Mach number conditions.

Description

Technical Field

[0001] This invention relates to the field of supersonic inlet start-up and active flow control technology, and more specifically, to a miniature supersonic nozzle array device and engine for enhancing inlet start-up. Background Technology

[0002] The scramjet engine (Supersonic Combustion Ramjet) is the core propulsion system of supersonic aircraft, such as... Figure 1 As shown, fuel-air mixing, efficient ignition, and stable combustion must be completed in supersonic airflow (Ma≥5), and its performance directly determines the speed limit and mission reliability of the aircraft. Figure 1 The direction of the middle arrow indicates the direction of gas flow.

[0003] However, the engine's start-up and steady-state combustion are highly dependent on the flow compression efficiency of the intake manifold and the stability of the flow field at the combustion chamber inlet. Among these issues, problems such as intake manifold flow separation, shock wave boundary layer interference (SWBLI), and start-up hysteresis remain key bottlenecks restricting its engineering application.

[0004] Under high-speed flight conditions (Ma≥5), the start-up control of the scramjet engine inlet faces multiple technical bottlenecks.

[0005] First, the intake lip and compression surface shock system are highly sensitive to boundary layer disturbances. They are prone to flow separation caused by strong reverse pressure gradients (such as combustion chamber back pressure fluctuations) or shock wave boundary layer interference (SWBLI), resulting in a sharp drop in total pressure recovery rate (>15%) and a deviation of the combustion chamber inlet Mach number from the design value (such as Ma=2.5→Ma=1.8), which directly threatens ignition and combustion stability.

[0006] Secondly, traditional passive control technologies (such as fixed geometry optimization, throat area adjustment, and inlet transition plates) are difficult to adapt to dynamic flight environments (such as changes in angle of attack and gust disturbances), while active flow control methods (such as boundary layer suction, synthetic jet, and plasma excitation) are limited by problems such as high system power consumption (such as the need for complex pipelines for suction devices), insufficient energy injection (the control capability of synthetic jets is reduced under Ma≥6 conditions), and response delay (such as plasma excitation is only applicable to Ma<4), making it difficult to achieve efficient intervention in three-dimensional unsteady flows (such as separated bubble oscillation and shock train instability).

[0007] In addition, existing active flow control devices mostly rely on a single control strategy (such as single-point jet) or static parameter matching, lacking the ability to adaptively adjust to multi-parameter coupling (such as Reynolds number, angle of attack, and thermal protection ablation effect), resulting in a high failure rate of aircraft start-up under complex operating conditions (such as a 30% failure rate in NASA X-51A tests).

[0008] The above problems urgently need to be solved, and a lightweight, low-power, and dynamically responsive inlet flow control device needs to be designed to overcome the limitations of traditional technologies in terms of start-up robustness and flow stability. Summary of the Invention

[0009] The present invention aims to provide a micro supersonic nozzle array device and engine for enhancing inlet start-up, in order to solve the problems of inlet flow separation, shock wave boundary layer interference and start-up lag in existing scramjet engines.

[0010] This invention is achieved using the following technical solution:

[0011] This invention provides a miniature supersonic nozzle array device for enhancing inlet start-up, comprising a rotating mechanism on which multiple nozzles are mounted, the multiple nozzles being arranged at intervals.

[0012] The airflow channel inside the nozzle is an acceleration channel, and the airflow channel between two adjacent nozzles is a deceleration channel.

[0013] The acceleration channel is divided into an acceleration channel inlet section, a middle contraction section and an acceleration channel outlet section along the gas flow direction. The cross-sectional dimensions of the middle contraction section are smaller than those of the acceleration channel inlet section and the acceleration channel outlet section.

[0014] As a preferred technical solution:

[0015] The accelerating flow channel and the decelerating flow channel are arranged alternately to form a flow channel array.

[0016] As a preferred technical solution:

[0017] The nozzle is a variable cross-section pipe, and multiple nozzles are arranged at intervals along the width direction of the air intake.

[0018] The deceleration channel is divided into a deceleration channel inlet section, a middle expansion section and a deceleration channel outlet section along the gas flow direction. The lateral dimension of the middle expansion section is larger than the lateral dimensions of the deceleration channel inlet section and the deceleration channel outlet section.

[0019] As a preferred technical solution:

[0020] The nozzle includes straight pipe sections at both ends and an arc-shaped concave pipe section in the middle, with a smooth transition between the straight pipe sections at both ends and the arc-shaped concave pipe section in the middle.

[0021] As a preferred technical solution:

[0022] The rotating mechanism is connected to the driving mechanism, and the driving mechanism can drive the rotating mechanism to rotate.

[0023] As a preferred technical solution:

[0024] The rotating mechanism rotates around its geometric center, and the rotation angle of the rotating mechanism is in the range of 0° to 30°.

[0025] As a preferred technical solution:

[0026] The rotating mechanism adopts a rotating frame, and the nozzle is fixedly installed on the rotating frame.

[0027] As a preferred technical solution:

[0028] The cross-section of the arc-shaped concave pipe section is wave-shaped.

[0029] The present invention further provides an engine in which the above-mentioned micro supersonic nozzle array device for enhancing intake start-up is provided in the intake duct of the engine, and the rotating mechanism of the micro supersonic nozzle array device for enhancing intake start-up is rotatably connected to the intake duct.

[0030] As a preferred technical solution:

[0031] The air intake has a rectangular cross-section, and the rotating mechanism is rotatably connected to the upper or lower surface inside the air intake.

[0032] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0033] The miniature supersonic nozzle array device for inlet start-up enhancement of the present invention effectively solves key problems such as inlet lip shock boundary layer interference, flow separation, start-up hysteresis and control strategy lag caused by the innovative design and optimization of the core structure. At the same time, it realizes lightweight, low power consumption and multi-point coordinated active flow control, which significantly improves the start-up robustness and combustion stability of scramjet engines in the entire flight corridor.

[0034] This invention dynamically controls the inlet flow field structure of the intake duct by using an alternating arrangement of accelerating and decelerating flow channels and a synergistic design with a rotating mechanism. This enhances the mixing capacity and flow rate of the intake duct wall, promotes early boundary layer transition and suppresses flow separation, solves the problem of boundary layer interference from the intake duct lip shock wave under high Mach number conditions, and improves the self-starting capability and combustion stability of the supersonic intake duct.

[0035] This invention reduces the intensity of shock waves generated by the inward bulge in the middle of the nozzle by refining the nozzle design.

[0036] This invention uses a rotating mechanism to rotate the nozzle and adjust its angle. By controlling the array angle of attack according to the incoming flow state, the micro supersonic nozzle array device can enhance or weaken the ability to control the flow separation of the inlet under different incoming flow states, thereby achieving controlled boundary layer flow separation.

[0037] This invention enhances the gas velocity, flow rate, and wall momentum exchange through the accelerated flow channel, suppressing boundary layer flow separation and solving the problem of start-up lag caused by unstable airflow during startup. This invention also achieves active and real-time control of inlet flow separation by actively adjusting the angle of the rotating mechanism through the drive mechanism, solving the problem of start-up failure caused by lagging control strategy. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of an existing scramjet engine.

[0039] Figure 2 This is a top view of the arrangement of the micro supersonic nozzle array device for enhancing inlet start-up as described in this invention within the inlet.

[0040] Figure 3 This is a cross-sectional view of the nozzle described in this invention.

[0041] icon:

[0042] 1- Rotating mechanism;

[0043] 2-Acceleration Flow Channel;

[0044] 3-Decelerating flow channel;

[0045] 4-Air intake;

[0046] 401 - Air intake inlet;

[0047] 5- Nozzle;

[0048] 501 - Straight pipe section;

[0049] 502 - Arc-shaped concave pipe section. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] Example 1

[0052] like Figure 2and Figure 3 As shown, this embodiment proposes a micro supersonic nozzle array device for enhancing the start-up of the air intake, including a rotating mechanism 1, which is rotatably connected to the air intake 4, and the rotating mechanism 1 can rotate relative to the air intake 4 within a certain angle.

[0053] The rotating mechanism 1 is equipped with a plurality of nozzles 5, and the nozzles 5 can rotate with the rotating mechanism 1;

[0054] The plurality of nozzles 5 are arranged at intervals along the width direction of the air intake duct 4;

[0055] The airflow channel inside the nozzle 5 is an acceleration channel 2, used to pass high-speed fluid;

[0056] The airflow passage between two adjacent nozzles 5 is a deceleration channel 3, used to pass low-speed fluid;

[0057] In this way, an array of flow channels is formed in which the accelerating flow channel 2 and the decelerating flow channel 3 are arranged alternately.

[0058] The acceleration channel 2 is divided into an acceleration channel inlet section, a middle contraction section and an acceleration channel outlet section along the gas flow direction. The cross-sectional dimensions of the middle contraction section are smaller than those of the acceleration channel inlet section and the acceleration channel outlet section.

[0059] The nozzle 5 is a variable cross-section pipe. Since the acceleration channel 2 is sequentially divided into an acceleration channel inlet section, a central contraction section, and an acceleration channel outlet section along the gas flow direction, and the cross-sectional dimension of the central contraction section is smaller than that of the acceleration channel inlet section and the acceleration channel outlet section, the deceleration channel 3 can also be sequentially divided into a deceleration channel inlet section, a central expansion section, and a deceleration channel outlet section along the gas flow direction. The lateral dimension of the central expansion section is larger than that of the deceleration channel inlet section and the deceleration channel outlet section. Here, "lateral" refers to the width direction of the air intake 4. Figure 2 In the diagram, the straight arrow indicates the direction of gas flow, and the curved arrow indicates the direction of rotation of the rotating mechanism 1.

[0060] Here, "micro" refers to the size of the nozzle 5 being in the centimeter range, and the inner diameter of the nozzle 5 is preferably 3cm-8cm, with the specific size selected according to the size of the air intake 4.

[0061] Preferably, the nozzle 5 includes straight pipe sections 501 at both ends and an arc-shaped concave pipe section 502 in the middle. The straight pipe sections 501 at both ends and the arc-shaped concave pipe section 502 in the middle are smoothly transitioned, and the overall shape of the nozzle 5 is continuous without abrupt changes.

[0062] Preferably, the rotating mechanism 1 is connected to the driving mechanism, and the driving mechanism can drive the rotating mechanism 1 to rotate.

[0063] Preferably, the rotating mechanism 1 rotates around its geometric center, and the rotation angle of the rotating mechanism 1 is in the range of 0° to 30°.

[0064] Preferably, the rotating mechanism 1 may be, but is not limited to, a rotating frame, and the nozzle 5 is fixedly installed on the rotating frame. The fixing method is not strictly limited, as long as it can be fixed on the rotating frame.

[0065] Preferably, the air intake duct 4 has a rectangular cross-section, and the rotating mechanism 1 is rotatably connected to the upper or lower surface inside the air intake duct 4.

[0066] Preferably, the microsonic nozzle array device of the present invention determines the profile of the nozzle 5 based on the flight envelope. To reduce the influence of the microsonic nozzle array device on the drag of the aircraft inlet 4, the normal height of the nozzle 5 increases from the middle to both ends of the wall, with a maximum height preferably 2cm to 3cm. The slope of the nozzle 5 from the middle to both ends is preferably 5° to 15°. To reduce the shock wave intensity generated by the inward bulge in the middle of the nozzle 5 (i.e., the arc-shaped concave pipe section 502), the cross-section of the arc-shaped concave pipe section 502 is wave-shaped. The length of the nozzle 5 along the gas flow direction is preferably 10cm to 20cm.

[0067] This invention considers that parameters in the flight envelope (such as Reynolds number, angle of attack, and sideslip angle) are dynamically changing objective factors, but passive control methods are only effective under designed conditions. Therefore, to enhance the ability of the microsonic nozzle array device to regulate flow separation in the inlet 4 under different incoming flow conditions, this invention incorporates a rotating mechanism 1. This rotating mechanism 1 can rotate within a certain angle range around its geometric center, thereby regulating boundary layer flow separation. Unlike traditional passive control, which is only effective under designed conditions, this invention's microsonic nozzle array device can adjust the array angle of attack according to the incoming flow condition, enhancing or weakening its ability to regulate flow separation in the inlet 4 under different incoming flow conditions. By analyzing the flight attitude of the high-speed aircraft, such as angle of attack and sideslip angle, the incoming flow angle of the inlet 4 is identified. The rotating mechanism 1 is then controlled to rotate within a certain angle range via a drive mechanism, achieving perpendicularity between the microsonic nozzle array device and the incoming flow in the inlet 4, effectively regulating boundary layer flow separation, and thus achieving adaptive control.

[0068] This invention arranges multiple nozzles 5 at intervals along the width of the air intake duct 4 to form an array of flow channels where acceleration channels 2 and deceleration channels 3 are arranged alternately. This creates alternating high and low speed strips, resulting in a compact structure with no redundant parts and a small overall size. This achieves miniaturization and lightweight design. The acceleration channels 2 enhance the gas velocity, flow rate, and wall momentum exchange passing through the device, resulting in stronger boundary layer flow separation capabilities. Moreover, it eliminates the need for additional large amounts of energy from the aircraft, unlike wall suction devices.

[0069] This invention uses a micro-supersonic nozzle array device to replace the traditional transition vane. The micro-supersonic nozzle array device of this invention can form local jet excitation (high and low speed strips) through the alternating arrangement of acceleration channels 2 and deceleration channels 3. Combined with the rotation function of the rotating mechanism 1, the alternating arrangement of acceleration channels 2 and deceleration channels 3 and the coordinated design of the rotating mechanism 1 can dynamically control the inlet flow field structure of the intake duct 4, generating speed strips with greater speed differences, thereby enhancing the mixing capacity and flow rate of the intake duct 4 wall, promoting early boundary layer transition and suppressing flow separation, and improving the self-starting capability and combustion stability of the supersonic intake duct 4.

[0070] The miniature supersonic nozzle array device for inlet start-up enhancement of the present invention effectively solves key problems such as inlet lip shock boundary layer interference, flow separation, start-up hysteresis and control strategy lag caused by the innovative design and optimization of the core structure. At the same time, it realizes lightweight, low power consumption and multi-point coordinated active flow control, which significantly improves the start-up robustness and combustion stability of scramjet engines in the entire flight corridor.

[0071] Example 2

[0072] This embodiment proposes an engine in which a micro supersonic nozzle array device for enhancing the start-up of the air intake duct is provided in the air intake duct 4 as described in Embodiment 1. The rotating mechanism 1 of the micro supersonic nozzle array device for enhancing the start-up of the air intake duct is rotatably connected to the air intake duct 4.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A miniature supersonic nozzle array device for enhancing inlet start-up, characterized in that: It includes a rotating mechanism on which multiple nozzles are mounted, and the multiple nozzles are arranged at intervals; The airflow channel inside the nozzle is an acceleration channel, and the airflow channel between two adjacent nozzles is a deceleration channel. The acceleration channel is divided into an acceleration channel inlet section, a middle contraction section and an acceleration channel outlet section along the gas flow direction. The cross-sectional dimensions of the middle contraction section are smaller than those of the acceleration channel inlet section and the acceleration channel outlet section.

2. The micro supersonic nozzle array device for enhancing inlet start-up according to claim 1, characterized in that: The accelerating flow channel and the decelerating flow channel are arranged alternately to form a flow channel array.

3. The micro supersonic nozzle array device for enhancing inlet start-up according to claim 1, characterized in that: The nozzle is a variable cross-section pipe, and multiple nozzles are arranged at intervals along the width direction of the air intake. The deceleration channel is divided into a deceleration channel inlet section, a middle expansion section and a deceleration channel outlet section along the gas flow direction. The lateral dimension of the middle expansion section is larger than the lateral dimensions of the deceleration channel inlet section and the deceleration channel outlet section.

4. The micro supersonic nozzle array device for enhancing inlet start-up according to claim 3, characterized in that: The nozzle includes straight pipe sections at both ends and an arc-shaped concave pipe section in the middle, with a smooth transition between the straight pipe sections at both ends and the arc-shaped concave pipe section in the middle.

5. The micro supersonic nozzle array device for enhancing inlet start-up according to claim 1, characterized in that: The rotating mechanism is connected to the driving mechanism, and the driving mechanism can drive the rotating mechanism to rotate.

6. The micro supersonic nozzle array device for enhancing inlet start-up according to claim 5, characterized in that: The rotating mechanism rotates around its geometric center, and the rotation angle of the rotating mechanism is in the range of 0° to 30°.

7. The micro supersonic nozzle array device for enhancing inlet start-up according to claim 1, characterized in that: The rotating mechanism adopts a rotating frame, and the nozzle is fixedly installed on the rotating frame.

8. The micro supersonic nozzle array device for enhancing inlet start-up according to claim 4, characterized in that: The cross-section of the arc-shaped concave pipe section is wave-shaped.

9. An engine, characterized in that: The engine's air intake duct is provided with a micro supersonic nozzle array device for enhancing air intake duct startup as described in any one of claims 1-8, and the rotating mechanism of the micro supersonic nozzle array device for enhancing air intake duct startup is rotatably connected to the air intake duct.

10. The engine according to claim 9, characterized in that: The air intake has a rectangular cross-section, and the rotating mechanism is rotatably connected to the upper or lower surface inside the air intake.

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