High-speed boundary layer transition control device and control method based on micro-nano air film

Abstract

The application relates to a high-speed boundary layer transition control device and a control method based on micro-nano gas film, wherein the high-speed boundary layer transition control device comprises a gas seepage wall, a gas chamber, a gas supply device and a control device; the gas chamber surrounds the gas seepage wall, and a cavity for gas residence is formed between the gas seepage wall and the gas chamber; the gas chamber is connected with the gas supply device; the control device comprises a first sensor, a second sensor and a control unit; the control unit is connected with the first sensor, the second sensor and the gas supply device respectively; the first sensor is used for collecting cavity pressure in the cavity; along the direction of external airflow, the second sensor is used for collecting wall surface pressure of the high-speed boundary layer upstream of the gas seepage wall; the control unit adjusts the output flow of the gas in the gas supply device based on the cavity pressure, the wall surface pressure and a pressure matching relationship, and the gas seeps out through the gas seepage wall and forms a micro-nano gas film.

Description

Technical Field

[0001] This invention relates to the field of aircraft design technology, and in particular to a high-speed boundary layer transition control device and control method based on micro-nano gas films. Background Technology

[0002] High-speed boundary layer transition is not only a fundamental scientific problem in aerodynamics but also a major engineering challenge in addressing the aerodynamic and aerothermal aspects of high-speed aircraft. Research shows that the transition from laminar to turbulent flow in the high-speed boundary layer increases frictional drag and heat flux several times over. Precisely controlling the timing of this transition, whether earlier or later, plays a crucial role in improving the performance of high-speed aircraft.

[0003] Existing boundary layer transition control methods mainly include setting rough element arrays (steps, eddy current generators), controlling wall temperature, and surface control (corrugated walls, microchannels, porous media, or ultrasonic sound-absorbing materials). In practical engineering, it may be necessary to promote or delay transition. Based on whether energy input is required, these methods can be divided into passive and active control methods. Passive boundary layer transition control, because it does not require additional control energy, is technically simple and easy to implement, and has received considerable attention from domestic and international peers. Porous surfaces are one effective solution for controlling boundary layer transition. Active control methods can adjust the control effect by controlling the amount of energy input according to the state of the high-speed aircraft, offering greater flexibility and adapting to the diverse flight states of high-speed aircraft, such as high maneuverability, multi-mission, and wide speed range. Typical active control methods include wall heating / cooling, wall tangential jetting, wall normal suction, and jetting. Wall tangential jetting involves ejecting a supersonic gas film through a backward step, while wall normal suction and jetting use micropores or channel arrays to control the boundary layer's intake and exhaust.

[0004] Currently, neither passive nor active high-speed boundary layer transition control methods have been widely applied in the practical engineering of high-speed aircraft. Porous surfaces, a passive high-speed boundary layer transition control method, cannot adapt to the high maneuverability, multi-mission, and wide speed range characteristics of high-speed aircraft. Among active control methods, jet-based approaches have significant limitations due to their high air consumption and heavy self-load. Summary of the Invention

[0005] The purpose of this invention is to provide a high-speed boundary layer transition control device and control method based on micro-nano gas films.

[0006] To achieve the above-mentioned objectives, the present invention provides a high-speed boundary layer transition control device based on micro-nano gas films, comprising: a gas permeation wall, a gas storage chamber, a gas supply device, and a control device;

[0007] The gas-retention chamber surrounds the gas-exudation wall, and the gas-exudation wall and the gas-retention chamber form a cavity for gas retention.

[0008] The gas chamber is connected to the gas supply device;

[0009] The control device includes: a first sensor, a second sensor, and a control unit;

[0010] The control unit is connected to the first sensor, the second sensor, and the gas supply device, respectively.

[0011] The first sensor is used to collect the cavity pressure in the cavity;

[0012] Along the direction of external airflow, the second sensor is located upstream of the gas permeation wall to collect the wall pressure of the high-speed boundary layer upstream of the gas permeation wall;

[0013] The control unit adjusts the output flow rate of the gas in the gas supply device based on the cavity pressure, the wall pressure and a preset pressure matching relationship, and the gas permeates through the micro-nano pores of the gas permeation wall to form a gas film.

[0014] According to one aspect of the invention, the gas membrane is a micro-nano gas membrane at the micro-nano scale.

[0015] According to one aspect of the invention, along the permeation direction of the gas, the flow area of ​​the gas gradually increases and the flow velocity gradually decreases.

[0016] According to one aspect of the invention, along the gas seepage direction, the porosity of the gas seepage wall gradually increases, and the average pore radius of the micro-nano pores gradually decreases.

[0017] According to one aspect of the invention, along the gas permeation direction, the porosity on the inner side of the gas permeation wall is 20% to 30%, and the porosity on the outer side of the gas permeation wall is 70% to 80%.

[0018] Along the gas seepage direction, the average pore radius of the micro-nano pores on the inner side of the gas seepage wall is greater than 0.5 mm and less than 1 mm, and the average pore radius on the outer side of the gas seepage wall is less than 10 μm.

[0019] According to one aspect of the present invention, the gas permeation wall comprises: a plurality of interconnected micro-nano pore layers: wherein the porosity and the radius of the micro-nano pores of each micro-nano pore layer are different, and the micro-nano pores of adjacent micro-nano pore layers are interconnected;

[0020] The micro-nano porous layer is a sintered metal powder layer, or a metal mesh layer, or a porous ceramic layer; or a carbon / carbon porous material layer.

[0021] According to one aspect of the invention, the gas supply device includes: a storage tank, a connecting pipe (32), and a flow control valve disposed on the connecting pipe;

[0022] The two opposite ends of the connecting pipe are respectively connected to the storage tank and the gas chamber;

[0023] The flow control valve is connected to the control unit;

[0024] The gas stored in the storage tank is one of air, carbon dioxide, hydrogen, helium, argon, and sulfur hexafluoride.

[0025] According to one aspect of the present invention, the preset pressure matching relationship in the control unit is expressed as follows:

[0026]

[0027] Where p1 is the wall pressure, p2 is the cavity pressure, and k is the pressure matching coefficient, and satisfies the following conditions: μ is the momentum viscosity coefficient of the gas in the storage tank, ρ is the density of the gas in the storage tank, Δn is the thickness of the gas permeation wall, α is the permeability of the gas permeation wall, C2 is the inertial drag coefficient of the gas permeation wall, and u is the average velocity of the gas film as it permeates from the gas permeation wall, satisfying u < 0.1 m / s.

[0028] To achieve the above-mentioned objectives, the present invention provides a control method employing the aforementioned high-speed boundary layer transition control device, comprising:

[0029] S1. The gas permeation wall is embedded in the side wall of the target structure, and the gas retention chamber is installed on the inner side of the side wall, and the gas retention chamber surrounds the gas permeation wall to form a cavity between the gas permeation wall and the gas retention chamber.

[0030] S2. The second sensor in the control device is installed inside the side wall, the first sensor in the control device is installed on the gas chamber, and the control unit of the control device is connected to the first sensor, the second sensor and the flow control valve of the gas supply device respectively; wherein, a pressure measuring hole for communicating with the outside is provided at the position of the side wall corresponding to the second sensor;

[0031] S3. The control unit collects the wall pressure of the high-speed boundary layer upstream of the gas seepage wall based on the second sensor, and collects the cavity pressure in the cavity based on the first sensor;

[0032] The control unit controls the opening and closing degree of the flow control valve based on the wall pressure, the cavity pressure and a preset pressure matching relationship, so as to control the gas to seep out through the micro-nano pores of the gas seepage wall and form a gas film.

[0033] According to one aspect of the present invention, in step S1, the outer surface of the gas permeation wall is flush with the wall surface of the target structure;

[0034] In step S2, the diameter of the pressure measuring hole is 0.5mm-1mm.

[0035] According to one aspect of the present invention, the present invention is based on a micro-nano gas film method, which controls the angle from the near-wall region of the high-speed boundary layer, requiring only a very small amount of gas to achieve the control effect.

[0036] According to one aspect of the present invention, a uniform and stable microscale gas film is infiltrated into the near-wall region of a high-speed boundary layer through a gas permeation wall with micro-nano pores, thereby influencing the high-speed boundary layer and regulating the gas film to achieve the goal of actively controlling the transition of the high-speed boundary layer.

[0037] According to one aspect of the present invention, the present invention employs a gas permeation wall with micro-nano pores, the surface pores of which have statistically uniform characteristics, the influence of surface roughness can be ignored, the shape of the high-speed aircraft is not changed, and it can adapt to the curved surface design of the aircraft.

[0038] According to one aspect of the present invention, the present invention acquires the pressure in the near-wall region of the high-speed boundary layer through a second pressure sensor, adaptively adjusts the permeation mass flow rate of the micro-nano gas film to meet a specific pressure matching relationship, and can cope with changes in flight conditions.

[0039] According to one aspect of the present invention, compared with the supersonic jet control method, the gas flow rate consumed by the micro-nano gas film of the present invention is as low as 1‰ of the mass flow rate of the high-speed incoming flow. The energy input of the entire active control system is less, and the volume of the storage tank and the gas chamber is smaller. The volume of the storage tank can be reduced by 90%, and the gas chamber can be designed as a thin cavity similar to the shape of the aircraft wall. The structure is simple and easy to install inside the high-speed aircraft.

[0040] According to one aspect of the present invention, the pressure, thickness and velocity characteristics of the micro-nano gas film can be accurately adjusted by the control device to meet the requirements of pressure resistance and micro-nano scale, and the gas leakage velocity is close to zero and has the requirement of small disturbance. Attached Figure Description

[0041] Figure 1 This is a schematic diagram illustrating the structure of a high-speed boundary layer transition control device according to an embodiment of the present invention;

[0042] Figure 2This is a schematic diagram illustrating the velocity change of high-speed airflow at the wall surface before and after the percolation of the micro-nano gas film in a high-speed boundary layer transition control device according to an embodiment of the present invention.

[0043] Figure 3 This is a schematic diagram illustrating the installation structure of the gas permeation wall 1 and the gas stagnation chamber 2 in the nose cone portion of a high-speed boundary layer transition control device according to an embodiment of the present invention. Detailed Implementation

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0045] In describing embodiments of the present invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" express orientations or positional relationships based on the orientations or positional relationships shown in the relevant drawings. They are only for the convenience of describing the present 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, the above terms should not be construed as limitations on the present invention.

[0046] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described in detail here, but the embodiments of the present invention are not limited to the following embodiments.

[0047] like Figure 1As shown, according to one embodiment of the present invention, a high-speed boundary layer transition control device based on a micro / nano gas film includes: a gas permeation wall 1, a gas retention chamber 2, a gas supply device 3, and a control device 4. For ease of explanation, a pointed leading-edge plate a is used as the mounting base. The gas permeation wall 1 is embedded in the wall surface of the pointed leading-edge plate a, and the gas retention chamber 2 is located inside the wall surface to achieve connection with the gas permeation wall 1. In this embodiment, the gas retention chamber 2 surrounds the gas permeation wall 1, and the gas permeation wall 1 and the gas retention chamber 2 form a cavity for gas retention. The gas retention chamber 2 is connected to the gas supply device 3. In this embodiment, the control device 4 includes: a first sensor 41, a second sensor 42, and a control unit 43. The control unit 43 is connected to the first sensor 41, the second sensor 42, and the gas supply device 3, respectively. In this embodiment, both the first sensor 41 and the second sensor 42 are pressure sensors. The first sensor 41 is used to collect the cavity pressure in the cavity. Along the direction of external airflow, the second sensor 42 is located upstream of the gas permeation wall 1 and is used to collect the wall pressure of the high-speed boundary layer upstream of the gas permeation wall 1. In this embodiment, the control unit 43 adjusts the output flow rate of the gas in the gas supply device 3 based on the cavity pressure, the wall pressure, and a preset pressure matching relationship. Gas permeates through the micro-nano pores of the gas permeation wall 1 and forms a gas film. The preset pressure matching relationship refers to the pressure matching relationship that matches the changes between the cavity pressure and the wall pressure. Therefore, the control unit 43 can control the output flow rate of the gas in the gas supply device 3 based on the collected changes between the cavity pressure and the wall pressure to adjust the cavity pressure to match the wall pressure.

[0048] In this embodiment, the gas exudation wall 1 is flush with the wall surface of the leading edge plate a, that is, there is no step between the gas exudation wall 1 and the leading edge plate a, thus ensuring the flatness of the wall surface.

[0049] In this embodiment, the gas permeation wall 1 is installed on the leading edge plate a at a laminar and / or transition region of the high-speed boundary layer of the leading edge plate a. This arrangement effectively controls gas permeation into the boundary layer and the location of the transition.

[0050] In this embodiment, because the flow rate of the micro-nano gas film is very small, the gas chamber 2 does not need to withstand a large gas supply pressure and does not require a large volume cavity. Therefore, the gas chamber 2 can be placed very close to the gas exudation wall 1, leaving only a narrow flow channel in between. The gas chamber 2 configured as described above does not require a large amount of internal space in the high-speed aircraft. Therefore, the gas chamber 2 and the gas exudation wall 1 can be configured as a sandwich structure to achieve miniaturization and weight reduction, effectively ensuring the internal space of the aircraft.

[0051] like Figure 1 As shown, according to one embodiment of the present invention, the gas film is a micro / nano gas film with a thickness on the micro / nano scale. In this embodiment, the cavity is filled with gas, which then seeps out through the micro / nano pores of the gas permeation wall 1 and is injected into the near-wall region of the high-speed boundary layer, forming a gas film (hereinafter referred to as a micro / nano gas film) with a thickness on the micro / nano scale. Through the above arrangement, the formation of a micro / nano gas film on the outer side of the leading edge plate a slightly lifts the high-speed boundary layer, avoiding direct contact and friction between the high-speed airflow and the gas permeation wall 1, and changing the local wall boundary conditions of the leading edge plate a. The micro / nano gas film acts as a lubricating "air cushion," allowing the high-speed airflow to slide directly across it, spatially shifting the high-speed boundary layer downstream by a certain distance, thereby changing the transition position. Without the micro / nano gas film, the velocity U0 of the high-speed airflow at the wall surface is 0. The micro / nano gas film continues to be generated on the gas permeation wall 1, and the equivalent wall surface of the high-speed airflow is the micro / nano gas film, referred to as the "gas film wall surface." A slip velocity U appears on the surface of the air film. s ,like Figure 2 As shown, the original no-slip condition no longer applies, and the high-speed boundary layer slips on the micro / nano gas film, thus changing the flow state and the transition position.

[0052] In this embodiment, the thickness and initial velocity of the micro / nano gas film are actively controlled by the control unit 43 based on the wall pressure and by adjusting the output flow rate of the gas supply device 3 to change the cavity pressure. Specifically, the properties of the micro / nano gas film can be actively controlled according to different high-speed boundary layer states, thereby achieving the effect of actively controlling the transition of the high-speed boundary layer to be advanced or delayed. In this embodiment, the thickness of the micro / nano gas film is on the micro / nano scale, and the initial velocity when permeating from the wall of the gas permeation wall 1 is sufficiently small, close to zero, so the disturbance to the high-speed incoming flow is almost negligible, only altering the flow in the near-wall region of the high-speed boundary layer.

[0053] like Figure 1 As shown, according to one embodiment of the present invention, the gas flow area gradually increases and the flow velocity gradually decreases along the gas seepage direction. This configuration effectively achieves a deceleration and pressurization effect on the gas, and is more conducive to controlling the cavity pressure and the wall pressure in the near-wall region of the boundary layer to achieve a matching relationship. Specifically, along the gas seepage direction, the porosity of the gas seepage wall 1 gradually increases, thereby gradually increasing the gas flow area, and the average pore radius of the micro-nano pores gradually decreases, thereby reducing the additional impact of the roughness of the gas seepage wall surface on the high-speed boundary layer transition.

[0054] like Figure 1As shown, according to one embodiment of the present invention, along the gas permeation direction, the porosity on the inner side of the gas permeation wall 1 is 20% to 30%, and the porosity on the outer side of the gas permeation wall 1 is 70% to 80%; along the gas permeation direction, the average pore radius of the micro-nano pores on the inner side of the gas permeation wall 1 ranges from 0.5 mm to 1 mm, and the average pore radius on the outer side of the gas permeation wall 1 is less than 10 μm.

[0055] By setting the porosity and micro-nano pore radius of the inner and outer sides of the gas permeation wall 1 within the above range, the gas can be effectively decelerated and pressurized when passing through the gas permeation wall 1. This ensures stable and continuous gas permeation and avoids the influence on the external flow, providing a reliable guarantee for the "lubricating" effect of the formed micro-nano gas film.

[0056] like Figure 1 As shown, according to one embodiment of the present invention, the gas flow rate required for the micro / nano gas film is very small, as low as 1‰ of the high-speed incoming flow rate. This, in turn, enables the miniaturization of the gas chamber 2, gas supply device 3, etc.

[0057] like Figure 1 As shown, according to one embodiment of the present invention, the gas permeation wall 1 includes: a plurality of interconnected micro-nano pore layers: wherein the porosity and the radius of the micro-nano pores of each micro-nano pore layer are different, and the micro-nano pores of adjacent micro-nano pore layers are interconnected; in this embodiment, the micro-nano pore layer is a metal powder sintered layer, or, the micro-nano pore layer is a metal mesh layer, or, the micro-nano pore layer is a porous ceramic layer; or, the micro-nano pore layer is a carbon / carbon porous material layer.

[0058] like Figure 1 As shown, according to one embodiment of the present invention, the gas supply device 3 includes: a storage tank 31, a connecting pipe 32, and a flow control valve 33 disposed on the connecting pipe 32. In this embodiment, the two opposite ends of the connecting pipe 32 are connected to the storage tank 31 and the gas chamber 2, respectively; the flow control valve 33 is connected to the control unit 43. In this embodiment, the storage tank 31 has a small volume and does not need to carry a large amount of gas, thus occupying very little internal space in the high-speed aircraft.

[0059] like Figure 1As shown, according to one embodiment of the present invention, the gas stored in the storage tank 31 is one of air, carbon dioxide, hydrogen, helium, argon, and sulfur hexafluoride. The gas stored in the storage tank 31 is under high pressure to ensure its storage capacity and to regulate the cavity pressure. In this embodiment, the pressure matching relationship satisfied by the micro / nano gas membrane differs depending on the type of gas used. Therefore, it can be stored in the control unit 43 in a pre-set manner to ensure accurate control of the micro / nano gas membrane. It should be noted that the type of gas does not significantly affect the effect of the micro / nano gas membrane, because the high-speed boundary layer transition active control method based on the micro / nano gas membrane mainly utilizes the "lubricating" effect of the micro / nano gas membrane.

[0060] According to one embodiment of the present invention, the preset pressure matching relationship in the control unit 43 is expressed as follows:

[0061]

[0062] Where p1 is the wall pressure, p2 is the cavity pressure, and k is the pressure matching coefficient, and satisfies the following conditions: μ is the momentum viscosity coefficient of the gas in storage tank 31, ρ is the density of the gas in storage tank 31, Δn is the thickness of the gas seepage wall 1, α is the permeability of the gas seepage wall 1, C2 is the inertial drag coefficient of the gas seepage wall 1, and u is the average velocity of the gas film when it seeps out of the gas seepage wall 1.

[0063] In this embodiment, the average velocity of the gas film as it permeates from the gas permeation wall 1 can be calculated based on the volumetric flow rate Q of the flow control valve and the surface area A of the gas permeation wall 1:

[0064] In this embodiment, the micro-nano gas film property requirements are met, and the average velocity u when the gas film seeps out from the gas seepage wall 1 is less than 0.1 m / s.

[0065] In this embodiment, the pressure matching coefficient is a crucial parameter in the pressure matching relationship, determining the properties of the micro / nano gas film in this invention. By setting it within the aforementioned range, the effectiveness and reliability of the gas film are ensured.

[0066] like Figure 1 As shown, according to one embodiment of the present invention, a control method employing the aforementioned high-speed boundary layer transition control device includes:

[0067] S1. The gas infiltration wall 1 is embedded in the side wall of the target structure, and the gas retention chamber 2 is installed on the inner side of the wall, and the gas retention chamber 2 surrounds the gas infiltration wall 1, so that the gas infiltration wall 1 and the gas retention chamber 2 form a cavity.

[0068] S2. The second sensor 42 in the control device 4 is installed inside the side wall, the first sensor 41 in the control device 4 is installed on the gas chamber 2, and the control unit 43 of the control device 4 is connected to the first sensor 41, the second sensor 42 and the flow control valve 33 of the gas supply device 3 respectively; wherein, a pressure measuring hole for connecting to the outside is provided at the position of the side wall corresponding to the second sensor 42.

[0069] S3. The control unit 43 collects the wall pressure of the high-speed boundary layer upstream of the gas seepage wall 1 based on the second sensor 42, and the cavity pressure in the cavity collected by the first sensor 41.

[0070] The control unit 43 controls the opening and closing degree of the flow control valve 33 based on the wall pressure, cavity pressure and preset pressure matching relationship, so as to control the gas to seep out through the micro-nano pores of the gas seepage wall 1 and form a gas film.

[0071] According to one embodiment of the present invention, in step S1, the outer surface of the gas permeation wall 1 is flush with the wall surface of the target structure. In this embodiment, the gas permeation wall 1 is located in the laminar and / or transition region of the high-speed boundary layer of the target structure.

[0072] According to one embodiment of the present invention, in step S2, the diameter of the pressure measuring hole is 0.5mm-1mm. In this embodiment, the pressure measuring hole is a straight hole. This configuration enables communication with the external airflow, effectively preventing direct impact of high-speed airflow on the second sensor 42 and thus avoiding damage to the sensor, thus adapting to the harsh airflow environment of high-speed aircraft.

[0073] According to one embodiment of the present invention, in step S1, the target structure is at least one of the following: a cone, an elliptical cone, a spherical cone, a delta wing, and a swept wing of an aircraft.

[0074] like Figure 3As shown, taking the installation in the nose cone section of an aircraft as an example, the gas sump chamber 2 and the gas leakage wall 1 form a sandwich structure with a cavity in between. Specifically, the gas leakage wall 1 is embedded in a ring along the nose cone section of the aircraft, so that the inner and outer surfaces of the gas leakage wall 1 are flush with the inner and outer surfaces of the nose cone section of the aircraft, thus forming the complete overall structure of the nose cone section. The gas sump chamber 2 is spaced apart from the gas leakage wall 1, so that a certain cavity is formed between the gas sump chamber 2 and the gas leakage wall 1. In this embodiment, the gas sump chamber 2 includes: a chamber body and a side guard connected to the side of the chamber body. The shape of the side of the chamber body opposite to the gas leakage wall 1 is matched with the shape of the inner surface of the nose cone section of the aircraft, that is, it is set as a ring-shaped conical surface. In this embodiment, to achieve the sealing of the gas storage chamber 2 around the gas seepage wall 1, one end of the side baffle is fixedly connected to the side of the main body of the storage chamber, and the other end is fixed to the connection position between the gas seepage wall 1 and the nose cone of the aircraft, so as to ensure the sealing of the gas seepage wall 1. In this embodiment, the side baffle is provided with a connection port to achieve connection with the gas supply device 3. In this embodiment, to facilitate the installation of the gas storage chamber 2, the gas storage chamber 2 can also be set up in a multi-part splicing manner, so that it can be more easily and flexibly assembled in a confined space.

[0075] In another embodiment, the gas infiltration wall 1 can be pre-integrated into the gas storage chamber 2 and installed as a whole on the nose cone of the aircraft. This installation is more convenient and facilitates the complete coverage of the gas infiltration wall 1 by the gas storage chamber 2. The main body of the storage chamber and the side flange connected to the side of the main body form an annular groove structure. The edge of the gas infiltration wall 1 rests against the end of the side flange away from the main body of the storage chamber, and a portion of the end face of the side flange away from the main body of the storage chamber is connected to the edge of the gas infiltration wall 1, while the remaining end face is used for fixed connection with the nose cone of the aircraft. In this embodiment, the side flange is provided with a connection port for connection to the gas supply device 3.

[0076] In another embodiment, the gas-containing chamber 2 can form a sandwich structure that directly contacts the gas-permeable wall 1. The gas-containing chamber 2 is generally plate-shaped, with interconnected regular grooves or recesses on its side adjacent to the gas-permeable wall 1. This allows a cavity to be formed between the gas-permeable wall 1 and the gas-containing chamber 2, while simultaneously enabling the gas-permeable wall 1 to rest against the gas-containing chamber 2. In this embodiment, to avoid the impact of the supporting portion of the gas-containing chamber 2 on the gas-permeable wall 1, the plane of the supporting portion can be further designed as a curved surface with an arc, further reducing the supporting area between the gas-containing chamber 2 and the gas-permeable wall 1. Additionally, the number of regular grooves or recesses can be increased to further reduce the supporting area, ensuring stable support for the gas-permeable wall 1 while maintaining sufficient gas storage space.

[0077] The above description is merely an example of a specific solution of the present invention. For any devices and structures not described in detail herein, it should be understood that they are implemented using common devices and methods already available in the art.

[0078] The above description is merely one embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements 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 high-speed boundary layer transition control device based on micro / nano gas films, characterized in that, include: Gas infiltration wall (1), gas storage chamber (2), gas supply device (3) and control device (4); The gas-retention chamber (2) surrounds the gas-exudation wall (1), and the gas-exudation wall (1) and the gas-retention chamber (2) form a cavity for gas retention; The gas-containing chamber (2) and the gas-permeable wall (1) form a sandwich structure with a cavity in the middle. The gas-containing chamber (2) is a plate-shaped body that abuts against the gas-permeable wall (1). Regular grooves or regular pits that are interconnected are provided on the side of the gas-containing chamber (2) adjacent to the gas-permeable wall (1). The gas chamber (2) is connected to the gas supply device (3); The control device (4) includes: a first sensor (41), a second sensor (42), and a control unit (43). The control unit (43) is connected to the first sensor (41), the second sensor (42) and the gas supply device (3) respectively; The first sensor (41) is used to collect the cavity pressure in the cavity; Along the direction of external airflow, the second sensor (42) is located upstream of the gas permeation wall (1) to collect the wall pressure of the high-speed boundary layer upstream of the gas permeation wall (1); The control unit (43) adjusts the output flow rate of the gas in the gas supply device (3) based on the cavity pressure, the wall pressure and the preset pressure matching relationship, and the gas permeates through the micro-nano pores of the gas permeation wall (1) to form a gas film. Along the gas seepage direction, the gas flow area gradually increases and the flow velocity gradually decreases, the porosity of the gas seepage wall (1) gradually increases, and the average pore radius of the micro-nano pores gradually decreases. The average pore radius on the outer side of the gas permeation wall (1) is less than 10 μm.

2. The high-speed boundary layer transition control device according to claim 1, characterized in that, The gas membrane is a micro-nano gas membrane at the micro-nano scale.

3. The high-speed boundary layer transition control device according to claim 2, characterized in that, Along the gas seepage direction, the porosity on the inner side of the gas seepage wall (1) is 20% to 30%, and the porosity on the outer side of the gas seepage wall (1) is 70% to 80%. Along the gas seepage direction, the average pore radius of the micro-nano pores on the inner side of the gas seepage wall (1) is greater than 0.5 mm and less than 1 mm.

4. The high-speed boundary layer transition control device according to claim 3, characterized in that, The gas permeation wall (1) includes: multiple interconnected micro-nano pore layers: wherein the porosity and radius of each micro-nano pore layer are different, and the micro-nano pores of adjacent micro-nano pore layers are interconnected. The micro-nano porous layer is a sintered metal powder layer, or a metal mesh layer, or a porous ceramic layer; or a carbon / carbon porous material layer.

5. The high-speed boundary layer transition control device according to claim 4, characterized in that, The gas supply device (3) includes: a storage tank (31), a connecting pipe (32), and a flow control valve (33) installed on the connecting pipe (32). The two ends of the connecting pipe (32) are respectively connected to the storage tank (31) and the gas chamber (2); The flow control valve (33) is connected to the control unit (43); The gas stored in the storage tank (31) is one of air, carbon dioxide, hydrogen, helium, argon, and sulfur hexafluoride.

6. The high-speed boundary layer transition control device according to claim 5, characterized in that, The preset pressure matching relationship in the control unit (43) is expressed as follows: in, For wall pressure, For cavity pressure, Let be the pressure matching coefficient, and satisfy... , The momentum-viscosity coefficient of the gas inside the storage tank (31) The density of the gas inside the storage tank (31), The thickness of the gas permeation wall (1) is given. The permeability of the gas permeation wall (1) is given by the permeability of the wall. Let be the inertial drag coefficient of the gas permeation wall (1). Let be the average velocity of the gas film as it permeates from the gas permeation wall (1), and satisfy . .

7. A control method employing the high-speed boundary layer transition control device according to any one of claims 1 to 6, characterized in that, include: S1. The gas permeation wall (1) is embedded in the side wall of the target structure, and the gas sump (2) is installed on the inside of the side wall, and the gas sump (2) surrounds the gas permeation wall (1) to form a cavity in the gas permeation wall (1) and the gas sump (2); S2. Install the second sensor (42) in the control device (4) inside the side wall, install the first sensor (41) in the control device (4) on the gas chamber (2), and connect the control unit (43) of the control device (4) to the first sensor (41), the second sensor (42) and the flow control valve (33) of the gas supply device (3) respectively; wherein, the side wall is provided with a pressure measuring hole for communicating with the outside at the position corresponding to the second sensor (42); S3. The control unit (43) collects the wall pressure of the high-speed boundary layer upstream of the gas seepage wall (1) based on the second sensor (42), and collects the cavity pressure in the cavity based on the first sensor (41); The control unit (43) controls the opening and closing degree of the flow control valve (33) based on the wall pressure, the cavity pressure and the preset pressure matching relationship, so as to control the gas to seep out through the micro-nano pores of the gas seepage wall (1) and form a gas film.

8. The control method of the high-speed boundary layer transition control device according to claim 7, characterized in that, In step S1, the outer surface of the gas permeation wall (1) is flush with the wall surface of the target structure; In step S2, the diameter of the pressure measuring hole is 0.5mm-1mm.

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