Method for the safety protection of a supersonic or hypersonic aircraft based on flow control

Abstract

The application discloses a supersonic or hypersonic aircraft safety protection method based on flow control, and is based on unsteady high-frequency pulse flow field excitation, adjusts the frequency and range of low-frequency pressure pulsation of a flow field discontinuity interference zone caused by unsteady motion of the flow field discontinuity, avoids strong coupling of the low-frequency pressure pulsation of the flow field discontinuity interference zone and an aircraft surface structure, and guarantees the integrity and reliability of the aircraft surface structure. The application is applied to the technical field of supersonic or hypersonic aircrafts, and by exerting unsteady high-frequency pulse flow field excitation on the flow field discontinuity interference zone of the supersonic or hypersonic aircraft, the safety protection capability of the aircraft can be effectively improved, by controlling the unsteady motion of the flow field discontinuity and locking at a specific frequency, the range of low-frequency pressure pulsation of the interference zone can be effectively reduced, thereby the vibration of the aircraft surface structure is reduced, and the safety protection of the supersonic or hypersonic aircraft is realized.

Description

Technical Field

[0001] This invention relates to the field of supersonic or hypersonic aircraft technology, specifically a safety protection method for supersonic or hypersonic aircraft based on flow control. Background Technology

[0002] Supersonic or hypersonic vehicles are characterized by their high detection difficulty, strong burst capability, high combat effectiveness, and rapid global reach, representing a new commanding height in the field of aerospace technology in the 21st century. However, as a new challenge to "extreme" environments and "extreme" dynamics, supersonic or hypersonic vehicles still face severe technical challenges and many key fundamental issues. One such challenge is the unsteady oscillation of the separation shock wave caused by the flow field discontinuity interference formed by the shock wave / boundary layer, which poses a serious threat to flight safety.

[0003] Shock wave / boundary layer discontinuity interference refers to phenomena such as boundary layer deformation, separation, reattachment, and shock wave bifurcation induced by the adverse pressure gradient generated by the shock wave. This is a complex flow phenomenon widely occurring under various flow field conditions, including transonic wing flows, supersonic inlets, high-speed aircraft control surfaces, and overexpansion nozzle flows. The presence of shock wave / boundary layer discontinuity interference often induces boundary layer separation, which in turn induces the generation of separated shock waves. The low-frequency unsteady oscillation characteristics of separated shock waves have been a focus of academic attention, as they can lead to aerodynamic oscillations in aircraft, instability in inlets, unpredictable high thermal loads in hypersonic aircraft, and severe localized ablation, posing a serious threat to flight safety. Furthermore, the low-frequency unsteady oscillations of separated shock waves are accompanied by pressure oscillations on the aircraft surface. When these pressure oscillations couple with the resonant frequency of the aircraft structure, they can also lead to fatigue failure of the aircraft structure. Studies have shown that in the local flow field where shock waves and turbulent boundary layers interact, the large-scale low-frequency oscillations caused by the separated shock waves result in surface pressure pulsations of up to 185 dB or more, and a considerable portion of the energy is concentrated in the structural response frequency range, which undoubtedly poses a serious threat to the safety and service life of aircraft. Summary of the Invention

[0004] To address the shortcomings of the prior art, this invention provides a safety protection method for supersonic or hypersonic vehicles based on flow control, thereby reducing vibration of the vehicle's surface structure and achieving safety protection for supersonic or hypersonic vehicles.

[0005] To achieve the above objectives, the present invention provides a safety protection method for supersonic or hypersonic vehicles based on flow control. Based on unsteady high-repetition-rate pulsed flow field excitation, the frequency and range of low-frequency pressure pulsations in the flow field discontinuity interference zone caused by unsteady motion of the flow field discontinuity are adjusted to avoid strong coupling between the pressure pulsations in the low-frequency interference zone of the flow field discontinuity and the surface structure of the vehicle, thereby ensuring the integrity and reliability of the surface structure of the vehicle.

[0006] In one embodiment, the adjustment of the frequency and range of low-frequency pressure pulsations in the flow field discontinuity interference zone caused by the unsteady motion of the flow field discontinuity based on unsteady high-repetition-rate pulse flow field excitation specifically involves:

[0007] By applying unsteady high-repetition-rate pulsed flow field excitation to the flow field discontinuity interference zone of a supersonic or hypersonic vehicle, the dynamic characteristics of the shear layer at the upper boundary of the separated bubble in the flow field discontinuity interference zone are controlled, thereby controlling the unsteady motion of the flow field discontinuity. The frequency of the unsteady motion of the flow field discontinuity is locked to the operating frequency of the unsteady high-repetition-rate pulsed flow field excitation, increasing the Strouhal number of low-frequency pressure pulsation in the flow field discontinuity interference zone, and reducing the range of low-frequency pressure pulsation in the flow field discontinuity interference zone. This eliminates structural vibrations on the surface of the vehicle and achieves safety protection for supersonic or hypersonic vehicles.

[0008] In one embodiment, the Strouhal number of the low-frequency pressure pulsation in the inter-sectional interference region of the improved flow field is specifically:

[0009] Adjust the frequency of low-frequency pressure pulsations in the flow field discontinuity interference zone to increase the Strouhal number of the pulsation frequency it causes from 0.03-0.04 to above 1, thereby moving it away from the aircraft's structural natural frequency.

[0010] In one embodiment, the range of reduced low-frequency pressure pulsations in the flow field discontinuity interference region specifically includes:

[0011] Adjust the range of low-frequency pressure pulsations in the inter-sectional interference zone of the flow field, reducing the range of low-frequency pressure pulsations caused by them from 30% of the length of the interference zone to less than 5%, thereby avoiding large-area vibrations on the surface structure of the aircraft.

[0012] In one embodiment, the unsteady high-repetition-rate pulsed flow field excitation has a continuous control mode and an intermittent control mode;

[0013] In the continuous control mode, unsteady high-repetition-rate pulse flow field excitation is continuously applied to the flow field discontinuity interference zone of the supersonic or hypersonic vehicle, so that the frequency and range of low-frequency pressure pulsation in the flow field discontinuity interference zone are continuously controlled.

[0014] In the intermittent control mode, unsteady high-repetition-rate pulse flow field excitation is applied intermittently and continuously to the flow field discontinuity interference zone of the supersonic or hypersonic vehicle, so that the frequency and range of low-frequency pressure pulsation in the flow field discontinuity interference zone are intermittently controlled, thereby reducing the energy consumption required for flow field excitation.

[0015] In one embodiment, in the intermittent control mode, the unsteady high repetition rate pulse flow field excitation is triggered once every 3-10 seconds, and the duration of each trigger is 1-3 seconds.

[0016] In one embodiment, the unsteady high-repetition-rate pulse flow field excitation is achieved through a homogeneous or heterogeneous distributed active flow control device array, and the active flow control devices are uniformly controlled by a central processing unit via photoelectric signals.

[0017] In one embodiment, the triggering method for the unsteady high-repetition-rate pulse flow field excitation is as follows:

[0018] The flow field is disturbed by high-frequency anomalous glow discharge and high-frequency laser-induced plasma to generate local high temperatures, thus producing unsteady high-repetition-rate pulsed flow field excitation; and / or

[0019] A mixture of free electrons and positive ions is generated through normal glow discharge. A Lorentz force is generated through the coupling of a magnetic field with this mixture, applying an unsteady, high-repetition-rate directional volume force to the subsurface fluid, thus generating an unsteady, high-repetition-rate pulsed flow field excitation; and / or

[0020] Gas is heated and pressurized by spark discharge or arc discharge, and the heated and pressurized gas is ejected at high speed, forming a high-temperature, high-speed jet in the interfacial interference zone of the flow field, generating unsteady high-repetition-frequency pulse flow field excitation; and / or

[0021] Utilizing the high-temperature, high-pressure carbon dioxide gas generated by the semi-Breen cycle active cooling and power generation system of the aircraft, a high-temperature, high-speed jet is formed in the flow field discontinuous interference zone, generating unsteady high-repetition-rate pulse flow field excitation; and / or

[0022] By utilizing the high-pressure zone behind the shock wave on the windward side of the aircraft, a high-speed jet is generated in the inter-sectional interference zone of the flow field through the ejector pipe. The frequency of the high-speed jet is controlled by a high-speed rotating orifice plate structure, thereby generating an unsteady high-repetition-rate pulse flow field excitation.

[0023] Compared with the prior art, the present invention has the following beneficial technical effects:

[0024] 1. This invention can effectively improve the safety protection capability of supersonic or hypersonic vehicles by applying unsteady high-repetition-frequency pulse flow field excitation to the flow field discontinuity interference zone. By controlling the unsteady motion of the flow field discontinuity and locking it at a specific frequency, the range of low-frequency pressure pulsation in the interference zone can be effectively reduced, thereby reducing the vibration of the surface structure of the vehicle.

[0025] 2. This invention can control the dynamic characteristics of the shear layer at the upper boundary of the separation bubble in the inter-discontinuous interference zone of the flow field by applying unsteady high-repetition-frequency pulse flow field excitation, thereby optimizing the flow structure in the interference zone, reducing the influence of vortex shedding and separation bubble, and improving the aerodynamic performance and stability of the aircraft;

[0026] 3. This invention can increase the Strouhal number by adjusting the operating frequency of the unsteady high-repetition-rate pulsed flow field excitation, thereby increasing the frequency of the vortex or separated bubble in the interference zone, improving the impact of flow field interference on the aircraft surface, and reducing structural vibration and noise generation. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0028] Figure 1 This is a flowchart of a safety protection method for supersonic or hypersonic aircraft based on flow control in an embodiment of the present invention.

[0029] Figure 2 This is a first isometric view of the jet generator in an embodiment of the present invention;

[0030] Figure 3 This is a second isometric view of the jet generator in an embodiment of the present invention;

[0031] Figure 4 This is a cross-sectional view of the jet generator in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the internal structure of the jet generator in an embodiment of the present invention.

[0033] Reference numerals: Structure 1, First plane 101, Second plane 102, Third plane 103, Fourth plane 104, Fifth plane 105, Sixth plane 106, Inlet channel 201, Gas collection chamber 202, First jet channel 203, Second jet channel 204, Third jet channel 205, Fourth jet channel 206, Discharge electrode 207.

[0034] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0035] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0037] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0038] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0039] This embodiment discloses a safety protection method for supersonic or hypersonic aircraft based on flow control. It primarily targets the safety protection of closed shock / boundary layer interference flow fields such as compression corners, incident / reflected shock waves, blunt supports, and flow around a cylinder, as well as open shock / boundary layer interference flow fields such as leading-edge support flow fields. It can be applied to the safety protection of shock wave interference inside scramjet inlets, shock wave interference caused by aircraft nose shock waves, normal shock wave interference on transonic wings, and shock wave interference on the surface of high-load compressor blades in aero-engines.

[0040] When a supersonic or hypersonic vehicle is at a certain Mach number and angle of attack, flow field discontinuities are formed at locations such as the ramjet engine inlet, the vehicle's forebody, and its wing rudders. These discontinuities interfere with the boundary layer on the vehicle surface, inducing the formation of separation bubbles in the flow field discontinuity interference zone. The separation bubbles and flow field discontinuities move at low frequencies, with the dominant Strouhal number between 0.03 and 0.04, causing low-frequency pressure pulsations. These low-frequency pressure pulsations cover up to 30% of the interference zone length, resulting in vibrations of the vehicle's surface structure. Therefore, this embodiment uses unsteady high-repetition-rate pulsed flow field excitation to adjust the frequency and range of low-frequency pressure pulsations in the flow field discontinuity interference zone induced by the unsteady motion of the flow field discontinuities. This avoids strong coupling between the pressure pulsations in the low-frequency interference zone and the vehicle's surface structure, ensuring the integrity and reliability of the vehicle's surface structure. Specifically: an unsteady high-repetition-rate pulsed flow field excitation is applied to the flow field discontinuity interference zone of a supersonic or hypersonic vehicle to control the dynamic characteristics of the shear layer at the upper boundary of the separated bubble in the flow field discontinuity interference zone, thereby controlling the unsteady motion of the flow field discontinuity and locking the frequency of the unsteady motion of the flow field discontinuity to the operating frequency of the unsteady high-repetition-rate pulsed flow field excitation. This increases the Strouhal number of the low-frequency pressure pulsation in the flow field discontinuity interference zone and reduces the range of the low-frequency pressure pulsation in the flow field discontinuity interference zone, thereby eliminating structural vibrations on the surface of the vehicle and achieving safety protection for supersonic or hypersonic vehicles.

[0041] In this embodiment, the Strouhal number is f·L / U ∞ Where f is the dominant frequency of the shock wave motion, L is the length of the interference region, and U ∞ This represents the mainstream velocity upstream of the interference zone.

[0042] In specific implementation, increasing the Strouhal number of low-frequency pressure pulsations in the flow field discontinuity interference zone involves adjusting the frequency of these pulsations to raise the Strouhal number from 0.03-0.04 to above 1, thereby moving them away from the aircraft's natural structural frequency. Reducing the range of low-frequency pressure pulsations in the flow field discontinuity interference zone involves adjusting the range of these pulsations to decrease the range of low-frequency pressure pulsations from 30% of the interference zone length to below 5%, thus avoiding large-area vibrations on the aircraft's surface structure. Unsteady high-repetition-rate pulse flow field excitation is achieved through a homogeneous or heterogeneous distributed active flow control device array. Each active flow control device is uniformly controlled by a central processing unit via photoelectric signals, and coordinated and matched using a neural network algorithm combining RNS / LES hybrid numerical simulation data driving and shock wave epipolar theory analysis model driving. (Reference) Figure 1 The safety protection method for supersonic or hypersonic aircraft based on flow control in this embodiment specifically includes the following steps:

[0043] Step 1: Arrange active flow control exciters in areas where there is flow field discontinuity interference, such as the ramjet engine inlet, the forebody, and the wing rudders of a supersonic or hypersonic vehicle. The exciters are located 25mm-50mm upstream of the flow field discontinuity interference area.

[0044] Step 2: When a supersonic or hypersonic vehicle is at a certain flight Mach number and angle of attack, and a separation bubble is induced to form in the flow field discontinuity interference zone, the active flow control exciter is activated to apply unsteady high-repetition-rate pulse flow field excitation to the flow field discontinuity interference zone. The excitation frequency Strouhal number reaches 1 or higher, causing the unsteady high-repetition-rate pulse flow field excitation to cause disturbance upstream of the flow field discontinuity interference zone. The disturbance effect is gradually amplified during the downstream propagation process and couples with the shear layer at the upper boundary of the separation bubble, changing the dynamic characteristics of the shear layer, thereby controlling the unsteady motion of the flow field discontinuity.

[0045] Step 3: Lock the unsteady motion frequency of the flow field discontinuity to the operating frequency of the flow control exciter. This increases the Strouhal number of the low-frequency pressure pulsation in the flow field discontinuity interference zone from 0.03-0.04 to over 1. The range of the low-frequency pressure pulsation in the flow field discontinuity interference zone decreases from 30% of the interference zone length to below 5%. Due to the change in the frequency and range of the low-frequency pressure pulsation in the flow field discontinuity interference zone, the vibration of the aircraft surface structure disappears, and the surface structure remains intact and reliable, achieving the effect of aircraft safety protection.

[0046] In this embodiment, the active flow control actuator triggers unsteady high-repetition-rate pulse flow field excitation in the following way:

[0047] The flow field is disturbed by high-frequency anomalous glow discharge and high-frequency laser-induced plasma to generate local high temperatures, thus producing unsteady high-repetition-rate pulsed flow field excitation; and / or

[0048] A mixture of free electrons and positive ions is generated through normal glow discharge. A Lorentz force is generated through the coupling of a magnetic field with this mixture, applying an unsteady, high-repetition-rate directional volume force to the subsurface fluid, thus generating an unsteady, high-repetition-rate pulsed flow field excitation; and / or

[0049] Gas is heated and pressurized by spark discharge or arc discharge, and the heated and pressurized gas is ejected at high speed, forming a high-temperature, high-speed jet in the interfacial interference zone of the flow field, generating unsteady high-repetition-frequency pulse flow field excitation; and / or

[0050] Utilizing the high-temperature, high-pressure carbon dioxide gas generated by the semi-Breen cycle active cooling and power generation system of the aircraft, a high-temperature, high-speed jet is formed in the flow field discontinuous interference zone, generating unsteady high-repetition-rate pulse flow field excitation; and / or

[0051] Utilizing the high-pressure region behind the shock wave at the aircraft's windward side, a high-speed jet is generated in the flow field discontinuity interference region through an ejector pipe. The frequency of the high-speed jet is controlled by a high-speed rotating orifice plate structure, generating unsteady high-repetition-rate pulsed flow field excitation; and / or

[0052] An unsteady high-repetition-rate pulse flow field excitation is generated using a controllable jet generator.

[0053] refer to Figures 2 to 5 This embodiment also provides a jet generator, which includes a wedge-shaped structure 1. The structure 1 includes a first plane 101 at the bottom, a second plane 102 and a third plane 103 at the top, a fourth plane 104 at the tail, and a fifth plane 105 and a sixth plane 106 on the sides. The first plane 101, the second plane 102, the third plane 103, and the fourth plane 104 are connected end to end in sequence to form a closed ring structure. The fifth plane 105 and the sixth plane 106 cover both sides of the ring structure, and the first plane 101 and the third plane 103 are both perpendicular to the fourth plane 104, that is, the first plane 101 and the third plane 103 are parallel to each other.

[0054] The structure 1 has a jet structure. The jet structure includes an air intake channel 201, an air collection chamber 202, a first jet channel 203, and a second jet channel 204, all located inside the structure 1. The air collection chamber 202 is a rectangular cavity, located inside the structure 1 and near the tail end of the third plane 103 and the fourth plane 104. The air intake channel 201 also has a rectangular cross-section, with its length parallel to the first plane 101. The first end of the air intake channel 201 is located on the second plane 102, and the second end of the air intake channel 201 is connected to the air collection chamber 202. The length of the first jet channel 203 is perpendicular to the third plane 103. Its first end is connected to the air collection chamber 202, and its second end is located in the central region of the third plane 103, so that the airflow enters the air collection chamber 202 through the air intake channel 201 and then forms a jet in the central region of the second plane 102 through the first jet channel 203. The second jet channel 204 is perpendicular to the fourth plane 104 in its length direction. Its first end communicates with the air collection chamber 202, and its second end is located in the central region of the fourth plane 104. This allows the airflow to enter the air collection chamber 202 via the air inlet channel 201 and then form a jet in the central region of the fourth plane 104 via the fourth jet channel 206. Preferably, the jet structure further includes a third jet channel 205 and a fourth jet channel 206 disposed inside the structure 1. The first end of the third jet channel 205 communicates with the air collection chamber 202, and the second end of the third jet channel 205 is located on the fifth plane 105. The first end of the fourth jet channel 206 communicates with the air collection chamber 202, and the second end of the fourth jet channel 206 is located on the sixth plane 106. The second end of the third jet channel 205 and the second end of the fourth jet channel 206 are inclined toward the top and tail of the structure 1, respectively, so that after the airflow enters the air collection chamber 202 through the air inlet channel 201, it also generates a suction jet that is inclined upwards and downstream of the jet generator through the third jet channel 205 and the fourth jet channel 206 at the fifth plane 105 and the sixth plane 106, respectively, thereby enhancing the flow control effect of the jet generator.

[0055] It is worth noting that in the jet structure, the first jet channel 203 and the second jet channel 204 are the main jet control parts, which need to generate a strong jet. The third jet channel 205 and the fourth jet channel 206 are the secondary jet control parts, mainly serving to enhance the jet effect. Therefore, the cross-sectional areas of the first jet channel 203 and the second jet channel 204 are basically the same, and their cross-sectional areas are larger than those of the third jet channel 205 and the fourth jet channel 206.

[0056] The jet structure also includes a discharge electrode 207, which is disposed within the gas collection cavity 202 and electrically connected to external control equipment via pre-embedded wires. By placing the discharge electrode 207 within the gas collection cavity 202, high-voltage discharge can be controlled during specific applications, thereby controlling the jet effect of the jet structure and generating unsteady high-repetition-rate pulse flow field excitation. This locks the unsteady motion frequency of the flow field discontinuity to the operating frequency of the flow control exciter, increasing the Strouhal number of low-frequency pressure pulsations in the flow field discontinuity interference zone from 0.03-0.04 to over 1, and reducing the range of low-frequency pressure pulsations in the flow field discontinuity interference zone from 30% of the interference zone length to below 5%. Due to the change in the frequency and range of low-frequency pressure pulsations in the flow field discontinuity interference zone, the vibration of the aircraft surface structure disappears, and the surface structure remains intact and reliable, achieving the effect of aircraft safety protection.

[0057] It is worth noting that, in specific applications, the connection between the air intake channel 201 and the air collection chamber 202 should be set as a stepped structure, and the height of the bottom wall of the air collection chamber 202 should be lower than the bottom wall of the air intake channel 201. At the same time, the discharge electrode 207 should be fixed to the bottom wall or the stepped wall of the air collection chamber 202, keeping the height of the discharge electrode 207 lower than the bottom wall of the air intake channel 201 to prevent the air intake airflow from interfering with the discharge of the discharge electrode 207.

[0058] The above-mentioned triggering methods for unsteady high repetition rate pulse flow field excitation do not require the aircraft to carry a large air source; they only need to use onboard batteries. This not only makes the structure simple but also occupies a small volume and does not impose an additional load on the aircraft.

[0059] In a preferred embodiment, the active flow control actuator has a continuous control mode and an intermittent control mode when triggering unsteady high-repetition-rate pulse flow field excitation, specifically:

[0060] In continuous control mode, unsteady high-repetition-rate pulse flow field excitation is continuously applied to the flow field discontinuity interference zone of the supersonic or hypersonic vehicle, so that the frequency and range of low-frequency pressure pulsation in the flow field discontinuity interference zone are continuously controlled.

[0061] In intermittent control mode, unsteady high-repetition-rate pulsed flow field excitation is applied intermittently and continuously to the flow field discontinuity interference region of the supersonic or hypersonic vehicle. This intermittently controls the frequency and range of low-frequency pressure pulsations in the flow field discontinuity interference region, thereby reducing the energy consumption required for flow field excitation. Specifically, in intermittent control mode, the unsteady high-repetition-rate pulsed flow field excitation is triggered once every 3-10 seconds, with each trigger lasting 1-3 seconds.

[0062] It is worth noting that the intermittent control mode of the aforementioned jet exciter, i.e., the discharge electrode 207 is turned off, makes the jet exciter function as an eddy current generator, thus providing a certain thermal protection effect on the aircraft wall. Simultaneously, during the thermal protection process, the jet exciter functions as a triangular wedge eddy current generator, except that, compared to a triangular wedge eddy current generator, this jet exciter replaces the sharp corner structure of the triangular wedge eddy current generator with the third plane 103 and the fourth plane 104. Since the sharp corner structure at the top of the triangular wedge eddy current generator inevitably generates significant drag when installed on the surface of a supersonic or hypersonic aircraft, and its sharp corner structure at the tail can also cause ablation problems, the jet generator in this embodiment replaces the sharp corners with planes, and the jets generated on the third plane 103 and the fourth plane 104 compensate for the removal of the sharp corners, thereby maintaining good flow control.

[0063] More preferably, the triggering mode of the unsteady high-repetition-rate pulsed flow field excitation can be adjusted in real time according to the supersonic or hypersonic vehicle. For example, during takeoff, landing, or attitude adjustment phases, the unsteady high-repetition-rate pulsed flow field excitation is triggered in continuous control mode. When the vehicle is in a constant-speed cruise phase, the unsteady high-repetition-rate pulsed flow field excitation is triggered in intermittent control mode. Depending on the flight speed, the unsteady high-repetition-rate pulsed flow field excitation is triggered once every 3-10 seconds in intermittent control mode, with each excitation lasting 1-3 seconds.

[0064] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A safety protection method for supersonic or hypersonic aircraft based on flow control, characterized in that, Based on the excitation of unsteady high repetition rate pulsed flow field, the frequency and range of low-frequency pressure pulsation in the flow field discontinuity interference zone caused by the unsteady motion of the flow field discontinuity are adjusted to avoid strong coupling between the pressure pulsation in the low-frequency interference zone of the flow field discontinuity and the surface structure of the aircraft, thus ensuring the integrity and reliability of the surface structure of the aircraft. The method of adjusting the frequency and range of low-frequency pressure pulsations in the flow field discontinuity interference zone caused by the unsteady motion of the flow field discontinuity based on unsteady high-repetition-rate pulse flow field excitation is specifically as follows: By applying unsteady high-repetition-rate pulsed flow field excitation to the flow field discontinuity interference zone of a supersonic or hypersonic vehicle, the dynamic characteristics of the shear layer at the upper boundary of the separated bubble in the flow field discontinuity interference zone are controlled, thereby controlling the unsteady motion of the flow field discontinuity. The frequency of the unsteady motion of the flow field discontinuity is locked to the operating frequency of the unsteady high-repetition-rate pulsed flow field excitation, increasing the Strouhal number of low-frequency pressure pulsation in the flow field discontinuity interference zone, and reducing the range of low-frequency pressure pulsation in the flow field discontinuity interference zone, the structural vibration on the surface of the vehicle is eliminated, and the safety protection of the supersonic or hypersonic vehicle is achieved. The Strouhal number of the low-frequency pressure pulsation in the inter-sectional interference zone of the enhanced flow field is specifically as follows: Adjust the frequency of low-frequency pressure pulsations in the inter-sectional interference zone of the flow field, and increase the Strouhal number of the pulsation frequency it causes from 0.03-0.04 to above 1, thereby moving it away from the natural frequency of the aircraft structure. The range for reducing low-frequency pressure pulsations in the flow field inter-sectional interference zone is specifically as follows: Adjust the range of low-frequency pressure pulsation in the inter-sectional interference zone of the flow field, and reduce the range of low-frequency pressure pulsation caused by it from 30% of the length of the interference zone to less than 5%, thereby avoiding large-area vibration of the aircraft surface structure. The unsteady high-repetition-rate pulsed flow field excitation has a continuous control mode and an intermittent control mode; In the continuous control mode, unsteady high-repetition-rate pulse flow field excitation is continuously applied to the flow field discontinuity interference zone of the supersonic or hypersonic vehicle, so that the frequency and range of low-frequency pressure pulsation in the flow field discontinuity interference zone are continuously controlled. In the intermittent control mode, unsteady high-repetition-rate pulse flow field excitation is applied intermittently and continuously to the flow field discontinuity interference zone of the supersonic or hypersonic vehicle, so that the frequency and range of low-frequency pressure pulsation in the flow field discontinuity interference zone are intermittently controlled, thereby reducing the energy consumption required for flow field excitation.

2. The safety protection method for supersonic or hypersonic aircraft based on flow control according to claim 1, characterized in that, In the intermittent control mode, the unsteady high-repetition-rate pulse flow field excitation is triggered once every 3-10 seconds, and the duration of each trigger is 1-3 seconds.

3. The safety protection method for supersonic or hypersonic aircraft based on flow control according to claim 1 or 2, characterized in that, The unsteady high-repetition-rate pulsed flow field excitation is achieved through a distributed active flow control device array that is homogeneous or heterogeneous, and the active flow control devices are uniformly controlled by a central processing unit via photoelectric signals.

4. The safety protection method for supersonic or hypersonic aircraft based on flow control according to claim 3, characterized in that, The triggering method for the unsteady high-repetition-rate pulse flow field excitation is as follows: The flow field is disturbed by high-frequency anomalous glow discharge and high-frequency laser-induced plasma to generate local high temperatures, thus producing unsteady high-repetition-rate pulsed flow field excitation; and / or A mixture of free electrons and positive ions is generated through normal glow discharge. A Lorentz force is generated through the coupling of a magnetic field with this mixture, applying an unsteady, high-repetition-rate directional volume force to the subsurface fluid, thus generating an unsteady, high-repetition-rate pulsed flow field excitation; and / or Gas is heated and pressurized by spark discharge or arc discharge, and the heated and pressurized gas is ejected at high speed, forming a high-temperature, high-speed jet in the interfacial interference zone of the flow field, generating unsteady high-repetition-frequency pulse flow field excitation; and / or The high-temperature, high-pressure carbon dioxide gas generated by the semi-Breen cycle active cooling and power generation system of the aircraft forms a high-temperature, high-speed jet in the flow field discontinuous interference zone, generating unsteady high-repetition-rate pulse flow field excitation; and / or By utilizing the high-pressure zone behind the shock wave on the windward side of the aircraft, a high-speed jet is generated in the inter-sectional interference zone of the flow field through the ejector pipe. The frequency of the high-speed jet is controlled by a high-speed rotating orifice plate structure, thereby generating an unsteady high-repetition-rate pulse flow field excitation.

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