Passive pneumatic vector two-dimensional plug nozzle based on throat jet flow and control method thereof

Abstract

The invention discloses a passive pneumatic vector two-dimensional plug nozzle based on throat jet flow and a control method thereof.The nozzle comprises a nozzle barrel and a center plug cone, the top and the bottom of the center plug cone are each provided with an expansion face, the first end of each expansion face is a shrinkage wall face, the middle of each expansion face is a throat wall face, and the second end of each expansion face is an expansion wall face; the center plug cone is provided with bypass channels corresponding to the two expansion faces, inlets of the bypass channels are formed in the shrinkage wall faces of the corresponding expansion faces, and outlets of the bypass channels are formed in the throat wall faces of the corresponding expansion faces and face the nozzle throat. And a bypass control valve is arranged on the bypass channel. The thrust vectoring nozzle is applied to the field of aircraft control, control over the piston nozzle vector is achieved through the bypass channel and the bypass control valve, the thrust vector of the thrust vectoring nozzle comes from vector deflection of airflow and the pressure difference between the upper side wall face and the lower side wall face of the nozzle, the response speed is high, and the performance is obviously higher than that of a conventional mechanical thrust vectoring nozzle.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft control, and specifically to a passive pneumatic vector dual plug nozzle based on throat jet and its control method. Background Art

[0002] Traditional mechanical thrust vectoring schemes are difficult to meet the strict requirements of these high-performance aircraft for thrust vector control due to their complex structure, response lag (usually exceeding 200 milliseconds), and poor reliability in high-temperature environments, which makes it urgent for the aerospace field to develop a new type of thrust vectoring technology.

[0003] Active pneumatic vectoring schemes can improve the response rate, but they require an additional air source from the engine, which increases the complexity of the system. Passive pneumatic schemes achieve thrust vector control by utilizing the natural characteristics of aerodynamic forces, avoiding the use of complex mechanical or hydraulic systems and without the need for an additional air source. This technology has significant advantages such as simple structure, high reliability, and light weight, providing a new solution for thrust vector control. The current passive pneumatic vector nozzles are mainly designed based on dual-throat nozzles, and their nozzle outlets are convergent, so they are only suitable for working conditions with relatively low flight Mach numbers. The plug nozzle, with its unique central plug structure, can achieve the dynamic expansion of the combustion gas, can take into account both low-speed and high-speed flight conditions, showing the characteristics of high efficiency, high adaptability, and light weight, and can maintain high working performance in a wide-speed working environment. Summary of the Invention

[0004] Aiming at the deficiencies in the above-mentioned prior art, the present invention provides a passive pneumatic vector dual plug nozzle based on throat jet and its control method, which can effectively increase the vector adjustment performance of the plug nozzle.

[0005] To achieve the above object, the present invention provides a passive pneumatic vector dual plug nozzle based on throat jet, including a nozzle barrel and a central plug cone coaxially arranged. The top and bottom of the central plug cone are both provided with outwardly convex expansion surfaces: The first end of the expansion surface is a converging wall surface for cooperating with the nozzle barrel to form a converging section; The middle part of the expansion surface is a throat wall surface for cooperating with the nozzle barrel to form a nozzle throat; The second end of the expansion surface is a diverging wall surface for cooperating with the nozzle barrel to form a diverging section; The central plug cone is provided with bypass channels corresponding to the two expansion surfaces. The inlets of the bypass channels are opened on the converging wall surfaces of the corresponding expansion surfaces, and the outlets of the bypass channels are opened on the throat wall surfaces of the corresponding expansion surfaces and face the nozzle throat; A bypass control valve is provided on the bypass channel and is used to control the flow area of the bypass control valve.

[0006] In one embodiment, the bypass channel includes a first flow channel and a second flow channel; The first end of the first flow channel is the inlet of the bypass channel. The first end of the second flow channel is connected to the second end of the first flow channel, and the second end of the second flow channel is the outlet of the bypass channel; The second end of the first flow channel is downstream of the outlet of the bypass channel in the flow direction within the engine.

[0007] In one embodiment, the first end of the central plug cone is located within the nozzle barrel, the second end of the central plug cone is located outside the nozzle barrel, and part of the expansion wall surface is located outside the nozzle barrel to reduce the influence of over-expansion or under-expansion.

[0008] In one embodiment, the diameter of the inlet of the bypass channel is 1 / 20 to 1 / 5 of the diameter of the nozzle throat. The outlet of the bypass channel is downstream of the center of the nozzle throat, and the diameter of the outlet of the bypass channel is 1 / 15 to 1 / 10 of the diameter of the nozzle throat.

[0009] In one embodiment, the axial distance between the center of the nozzle throat and the outlet of the bypass channel is 5% to 10% of the axial distance between the center of the nozzle throat and the second end of the central plug cone.

[0010] In one embodiment, the included angle between the orientation of the outlet of the bypass channel and the horizontal direction is 30° to 50°.

[0011] In one embodiment, when the passive pneumatic vector dual plug nozzle is applied to an aircraft with a flight Mach number of 0.3 to 1.5, the outlet diameter of the nozzle barrel is 0.3 m, and the axial length of the expansion wall surface is 0.4 m.

[0012] In one embodiment, when the passive pneumatic vector dual plug nozzle is applied to an aircraft with a flight Mach number of 1.2 to 4, the outlet diameter of the nozzle barrel is 0.6 m, and the axial length of the expansion wall surface is 1.2 m.

[0013] To achieve the above object, the present invention also provides a control method for the above-mentioned passive pneumatic vector dual plug nozzle based on throat jet, including the following steps: Arrange a micro pressure sensor array on the wall surface of the central plug cone corresponding to the downstream of the outlet of the bypass channel; During the flight of the aircraft, collect the pressure distribution data on the upper and lower wall surfaces of the central plug cone, and analyze the vector deflection state based on the collected pressure distribution data; Adjust the bypass control valve based on the error between the vector deflection state and the target deflection state.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects: 1. By optimizing the profile of the central plug cone and using the bypass channel and bypass control valve, the present invention realizes the control of the vector of the plug nozzle. Its thrust vector comes from the vector deflection of the air flow and the pressure difference between the upper and lower side walls of the nozzle. It not only has a very fast response rate and significantly higher performance than the conventional mechanical vector nozzle, but also amplifies the influence of the thrust vector by using the pressure difference between the upper and lower sides of the nozzle, thus significantly enhancing the acting effect. 2. The present invention can be directly retrofitted on a conventional plug nozzle with low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0016] Figure 1 It is a schematic structural diagram of a passive pneumatic vector dual plug nozzle in an embodiment of the present invention; Figure 2 It is a schematic diagram of the vector state of a passive pneumatic vector dual plug nozzle in an embodiment of the present invention; Figure 3 It is a schematic diagram of the non-vector state of a passive pneumatic vector dual plug nozzle in an embodiment of the present invention.

[0017] Reference numerals in the drawings: nozzle barrel 1, central plug cone 2, contraction wall surface 201, throat wall surface 202, expansion wall surface 203, contraction section 3, nozzle throat 4, expansion section 5, bypass channel 6, first flow channel 601, second flow channel 602, bypass control valve 7.

[0018] The realization, functional features and advantages of the object of the present invention will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0020] 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 conditions between components in a specific posture (as shown in the attached drawings). If the specific posture changes, the directional indications will also change accordingly.

[0021] In addition, in the present invention, descriptions such as "first" and "second" are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0022] In the present invention, unless otherwise clearly specified and limited, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, a physical connection or a wireless communication connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0024] As Figures 1 to 3 shown, a passive pneumatic vectoring dual plug nozzle (hereinafter referred to as "nozzle") based on throat jet disclosed in this embodiment mainly includes a coaxial nozzle barrel 1 and a central plug cone 2. The top and bottom of the central plug cone 2 are both provided with outwardly convex expansion surfaces. Among them, the first end of the expansion surface is a contraction wall surface 201, which is used to cooperate with the nozzle barrel 1 to form a contraction section 3; the middle part of the expansion surface is a throat wall surface 202, which is used to cooperate with the nozzle barrel 1 to form a nozzle throat 4; the second end of the expansion surface is an expansion wall surface 203, which is used to cooperate with the nozzle barrel 1 to form an expansion section 5. A bypass channel 6 corresponding to the two expansion surfaces is provided on the central plug cone 2. The inlet of the bypass channel 6 is opened on the contraction wall surface 201 of the corresponding expansion surface, and the outlet of the bypass channel 6 is opened on the throat wall surface 202 of the corresponding expansion surface and faces the nozzle throat 4. A bypass control valve 7 is provided on the bypass channel 6 to control the flow area of the bypass channel 6.

[0025] In this embodiment, the nozzle is designed with an embedded bypass channel 6 on the central plug cone 2, which splits two control airflows from the engine airflow and directs them to the nozzle throats 4 on the upper and lower sides respectively. At the same time, bypass control valves 7 are designed on the bypass channels 6 of each airflow to achieve flow control of the airflow. When one side of the bypass channel 6 is opened, the current airflow passage area on this side changes, and the airflow rates on the upper and lower sides are different. In addition, under the action of the bypass jet, flow separation and shock waves will appear near the wall surface, and the pressure distributions on the upper and lower side wall surfaces of the nozzle are also different. In addition, the two airflows on the upper and lower sides of the nozzle are no longer symmetrical during the flow process. After the airflows converge, the jet undergoes vector deflection. Under the combined action of the above three points, a significant vector thrust can be achieved.

[0026] In the specific implementation process, the bypass channel 6 includes a first flow channel 601 and a second flow channel 602. The first end of the first flow channel 601 is the inlet of the bypass channel 6. The first end of the second flow channel 602 is connected to the second end of the first flow channel 601. The second end of the second flow channel 602 is the outlet of the bypass channel 6. The second end of the first flow channel 601 is downstream of the outlet of the bypass channel 6 in the engine airflow direction, that is, there is a bend inside the bypass channel 6. This bend enables the bypass airflow to interact with the mainstream in a manner close to perpendicular to the mainstream airflow direction, thereby forming an aerodynamic throat, reducing the mainstream flow rate and flow state, and changing the wall attachment flow of the mainstream after passing through the throat.

[0027] In this embodiment, the first end of the central plug cone 2 is located inside the nozzle barrel 1, the second end of the central plug cone 2 is located outside the nozzle barrel, and part of the expansion wall surface 203 is located outside the nozzle barrel to reduce the influence of over-expansion or under-expansion. Preferably, the diameter of the inlet of the bypass channel 6 is 1 / 20 to 1 / 5 of the diameter of the nozzle throat 4. The outlet of the bypass channel 6 is located downstream of the center of the nozzle throat 4, and the diameter of the outlet of the bypass channel 6 is 1 / 15 to 1 / 10 of the diameter of the nozzle throat 4. The axial distance between the center of the nozzle throat 4 and the outlet of the bypass channel 6 is 5% to 10% of the axial distance between the nozzle throat 4 and the second end of the central plug cone 2. By designing the positions of the inlet and outlet of the bypass channel 6, it is possible to ensure that a sufficiently high-energy airflow flows out through the bypass channel and affects the flow state of the mainstream.

[0028] In the specific implementation process, the angle between the outlet direction of the bypass channel 6 and the horizontal direction is 30° to 80°. Preferably, the outlet airflow of the bypass channel 6 is perpendicular to the mainstream airflow direction. Further preferably, a mechanical adjustable vane structure can also be designed at the outlet of the bypass channel 6. By adjusting the angle of the vane, the jet angle can be adjusted to ensure the vector performance under different working conditions.

[0029] In this embodiment, the nozzle controls the thrust vector through the bypass control valve 7. When the bypass control valves 7 in both bypass controls are closed, the thrust vector angle is zero. When a single-side bypass control valve 7 is opened, the jet of the nozzle deflects vectorially, and at the same time, the pressure differences also appear on the upper and lower side walls of the nozzle, causing the nozzle to generate a pitching moment. In the specific application process, the profile of the nozzle can be changed according to requirements, specifically by changing the expansion surface (i.e., the expansion wall surface 203) between the throat 4 of the plug nozzle and the second end at the bottom of the central plug cone 2, thereby significantly changing the vector moment felt by the nozzle in the vector state. For example, for an aircraft with a flight Mach number of 0.3 to 1.5, the outlet diameter of the nozzle barrel 1 is 0.3 m, and the axial length of the expansion wall surface 203 is 0.4 m. For an aircraft with a flight Mach number of 1.2 to 4, the outlet diameter of the nozzle barrel 1 can be set to 0.6 m, and the axial length of the expansion wall surface 203 is 1.2 m This embodiment also discloses a control method for the above-mentioned passive pneumatic vector dual plug nozzle, which includes the following steps: Arrange a micro pressure sensor array on the wall surface of the central plug cone 2 corresponding to the downstream of the outlet of the bypass channel 6; During the flight of the aircraft, collect the pressure distribution data on the upper and lower wall surfaces of the central plug cone 2, and analyze the vector deflection state according to the collected pressure distribution data. For example, if the pressure distribution data shows that the pressure on the lower wall surface is greater than the pressure on the upper wall surface, it can be obtained that the nozzle is in a diving state; if the pressure distribution data shows that the pressure on the upper wall surface is greater than the pressure on the lower wall surface, it can be obtained that the nozzle is in a pulling-up state. In addition, more refined analysis can also combine the pressure data with the position of the pressure. By multiplying the pressure data by the position of the pressure point, the pitching moment can be obtained, and the magnitude of the current vector deflection can be given more directly.

[0030] Adjust the bypass control valve 7 based on the error between the vector deflection state and the target deflection state. For example, use a PID controller to control the opening degree of the bypass control valve 7.

[0031] In the specific implementation process, pressure sensors can also be arranged upstream of the nozzle throat 5 to evaluate the air flow rate by measuring the total pressure of the air flow. Under different air flow rates, the opening degree of the bypass control valve 7 needs to be adjusted. For example, when the same vector effect needs to be achieved, when the air flow rate is larger, the opening degree of the bypass control valve 7 also needs to be increased. At the same time, the opening degree of the bypass control valve 7 can also be determined by the valve control mode. In this embodiment, there are specifically two control modes, namely the jet deflection dominant mode and the wall pressure difference dominant mode. Among them, the jet deflection dominant mode is specifically that the vector thrust of the nozzle is mainly determined by the jet deflection angle of the outgoing air flow, and the wall pressure difference dominant mode is specifically that the vector thrust of the nozzle is mainly determined by the pressure difference between the upper and lower wall surfaces of the central cone 2.

[0032] In the specific application process, the control mode can be judged according to the ratio of the length L of the nozzle expansion surface to the outlet diameter D. Specifically, when L / D < 1.5, the nozzle is in the jet deflection dominant mode, and the flow control weight is relatively large; when L / D ≥ 1.5, it is in the wall pressure difference dominant mode, and the pressure feedback gain is increased.

[0033] The above are only the preferred embodiments of the present invention, and do not limit the protection scope of the present invention accordingly. Any equivalent structural transformation made by using the content of the specification and drawings of the present invention under the inventive concept of the present invention, or direct / indirect application in other related technical fields are all included in the protection scope of the present invention.

Claims

1. A passive pneumatic vectoring dual plug nozzle based on throat jet, characterized in that It includes a coaxial nozzle barrel and a central plug cone, and convex expansion surfaces are provided at both the top and bottom of the central plug cone: The first end of the expansion surface is a converging wall surface for cooperating with the nozzle barrel to form a converging section; The middle part of the expansion surface is a throat wall surface for cooperating with the nozzle barrel to form a nozzle throat; The second end of the expansion surface is a diverging wall surface for cooperating with the nozzle barrel to form a diverging section; Bypass channels corresponding to the two expansion surfaces are provided on the central plug cone. The inlet of the bypass channel is opened on the converging wall surface of the corresponding expansion surface, and the outlet of the bypass channel is opened on the throat wall surface of the corresponding expansion surface and faces the nozzle throat; A bypass control valve is provided on the bypass channel and is used to control the flow area of the bypass control valve.

2. The passive pneumatic vectoring dual plug nozzle based on throat jet according to claim 1, characterized in that, The bypass channel includes a first flow channel and a second flow channel; The first end of the first flow channel is the inlet of the bypass channel. The first end of the second flow channel is connected to the second end of the first flow channel, and the second end of the second flow channel is the outlet of the bypass channel; The second end of the first flow channel is downstream of the outlet of the bypass channel in the flow direction within the engine.

3. The passive pneumatic vectoring dual plug nozzle based on throat jet according to claim 1 or 2, characterized in that, The first end of the central plug cone is located inside the nozzle barrel, the second end of the central plug cone is located outside the nozzle barrel, and part of the diverging wall surface is located outside the nozzle barrel to reduce the influence of over-expansion or under-expansion.

4. The passive pneumatic vectoring dual plug nozzle based on throat jet according to claim 1 or 2, characterized in that The diameter of the inlet of the bypass channel is 1 / 20 to 1 / 5 of the diameter of the nozzle throat. The outlet of the bypass channel is located downstream of the center of the nozzle throat, and the diameter of the outlet of the bypass channel is 1 / 15 to 1 / 10 of the diameter of the nozzle throat.

5. The passive pneumatic vectoring dual plug nozzle based on throat jet according to claim 4, wherein The axial distance between the center of the nozzle throat and the outlet of the bypass channel is 5% to 10% of the axial distance between the center of the nozzle throat and the second end of the central plug cone.

6. The passive pneumatic vectoring dual plug nozzle based on throat jet according to claim 5, characterized in that, The included angle between the orientation of the outlet of the bypass channel and the horizontal direction is 30° to 50°.

7. The passive pneumatic vectoring dual plug nozzle based on throat jet according to claim 1 or 2, characterized in that, When the passive pneumatic vector dual plug nozzle is applied to an aircraft with a flight Mach number of 0.3 to 1.5, the outlet diameter of the nozzle barrel is 0.3 m, and the axial length of the diverging wall surface is 0.4 m.

8. The passive pneumatic vectoring dual plug nozzle based on throat jet according to claim 1 or 2, characterized in that, When the passive pneumatic vector dual plug nozzle is applied to an aircraft with a flight Mach number of 1.2 to 4, the outlet diameter of the nozzle barrel is 0.6 m, and the axial length of the diverging wall surface is 1.2 m.

9. A control method for a passive pneumatic vectoring dual plug nozzle based on throat jet according to any one of claims 1 to 8, characterized in that, It includes the following steps: Arrange a micro pressure sensor array on the wall surface of the central plug cone corresponding to the downstream of the outlet of the bypass channel; During the flight of the aircraft, collect the pressure distribution data on the upper and lower wall surfaces of the central plug cone, and analyze the vector deflection state based on the collected pressure distribution data; Adjust the bypass control valve based on the error between the vector deflection state and the target deflection state.

Images