A large-area variable-area ratio vector exhaust device and an exhaust method thereof

Abstract

The application relates to the technical field of vector thrust technology and discloses a large-range variable-area-ratio vector exhaust device and an exhaust method thereof. The device comprises a transition section, a guide vane section and a rotating afterbody; the guide vane section is connected with the outlet of the transition section, and the rotating afterbody is connected with the rear side of the transition section; when the device is switched between different working states including a vertical take-off and landing state, a transition state and a level flight state, the airflow direction and the jet angle are adjusted by changing the positions of the guide vane section and the rotating afterbody. The application can realize the continuous deflection of the airflow from 0 DEG to 90 DEG, ensure that an aircraft maintains excellent aerodynamic performance and generates sufficient thrust in different flight states, meet the large-outlet-area-ratio requirements in the vertical take-off and landing state and the level flight state, effectively cope with the large-flow change in the process from the vertical take-off to the level flight, realize a high total pressure recovery coefficient, improve the aerodynamic performance and provide strong thrust in the vertical take-off and landing state and the level flight state.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of vector thrust, in particular to a large-range variable-area-ratio vector exhaust device and an exhaust method thereof. BACKGROUND

[0002] The vertical take-off and landing technology significantly reduces the dependence of the aircraft on the landing runway, and even enables complete freedom, thereby greatly reducing the infrastructure demand of the landing area. Therefore, compared with the traditional fixed-wing aircraft, the vertical take-off and landing aircraft exhibits more excellent environmental adaptability, and has a wide application potential in the area with limited landing space or complex terrain (such as remote mountainous areas, city centers, earthquake disaster areas). With the continuous innovation of global vertical take-off and landing aircraft technology, the current mainstream technical paths mainly include the following four kinds:

[0003] 1) Multi-rotor aircraft: relying on multiple horizontally installed rotors to provide lift and thrust, and realizing attitude and direction control by adjusting the rotation speed of each rotor. For example, the T100 agricultural unmanned aerial vehicle of DJI and the EH216 manned eVTOL of Yihang Company are typical representatives of this kind.

[0004] 2) Compound helicopter: relying on the top rotor to generate lift during vertical take-off, similar to the traditional helicopter; and in the horizontal flight state, the horizontal engine installed on the two sides or the tail of the fuselage provides thrust. The X2 high-speed helicopter of the American Sikorsky Company and the Shengshi Long manned eVTOL of Fengfei Aviation Company are the main representatives.

[0005] 3) Tilt-rotor aircraft: changing the power direction by tilting the whole engine to realize the conversion between vertical take-off and horizontal flight. The S4 manned eVTOL of the American Joby Company and the V-22 Osprey tilt-rotor aircraft are typical applications.

[0006] 4) Jet deflection fixed-wing aircraft: using tiltable vector nozzles and duct fan technology to realize vertical take-off and horizontal flight, such as the Gyron combat aircraft of the United Kingdom and the F-35B of the United States.

[0007] The multi-rotor aircraft has relatively low level flight efficiency due to the lack of lifting surfaces such as wings. The compound helicopter adopts two independent power systems, but the vertical take-off and landing power system becomes an invalid load during level flight, affecting the loading efficiency. Although the tilt-rotor aircraft uses vector propulsion, the structure is complex and the aerodynamic control is challenging, miniaturization is difficult, and the actuating mechanism is heavy, reducing the load capacity.

[0008] In view of this, we propose a new power scheme, which adopts a rotor component (fan) in a fixed position, and deflects the jet flow through a vector exhaust device to realize the conversion of lift and thrust, without tilting the whole duct fan.

[0009] The vector thrust technology of the vertical take-off and landing aircraft experienced rapid development in the 1970s and 1980s, and various vector thrust configurations emerged, including exhaust nozzles with deflectors, louvered exhaust nozzles, ventral exhaust nozzles, and three-bearing rotating nozzles. However, due to the limitations of the technology at the time, only exhaust nozzles with deflectors and three-bearing rotating nozzles became the mainstream of research. These schemes are mainly suitable for the power layout of the F-35 type, which has a lift fan in front and a core turbine in back, and requires nozzle steering. In recent years, the aerodynamic vector nozzle, which is simpler in structure, has attracted the attention of many researchers. Although the aerodynamic vector nozzle has the problems of secondary flow injection and large flow loss, and the vector thrust deflection angle is difficult to reach ±45°, it is currently mainly used to improve the maneuverability of fighter aircraft. At the same time, the high expansion ratio (greater than 1.893) and high total pressure loss (usually more than 0.05) in the limit vector angle state of the conventional vector nozzle technology indicate that it is not suitable for non-tilting ducted fan power systems.

[0010] In recent years, improving the high-speed performance of vertical take-off and landing aircraft has become a research focus. This means that future aircraft need to have both vertical take-off and landing and high-speed cruising capabilities. The exhaust device outlet area of such aircraft must adapt to a large range of flow changes from vertical take-off to flat flying state to meet the outlet area ratio requirements in both states.

[0011] The existing technologies such as three-bearing rotating nozzles, guide vane exhaust devices, and conventional aerodynamic vector nozzles cannot achieve a large area change. Therefore, it is particularly important to develop a new type of vector exhaust device to adapt to the large outlet area ratio and high total pressure recovery coefficient requirements of the ducted fan of the vertical take-off and landing aircraft during high-speed cruising. SUMMARY

[0012] In view of the above technical deficiencies, the technical problem to be solved by the present application is to provide a large-range variable area ratio vector exhaust device and an exhaust method thereof, aiming to meet the large outlet area ratio and high total pressure recovery coefficient requirements of the ducted fan during vertical take-off and landing and high-altitude high-speed cruising, to realize efficient flow under a large range of exhaust angle changes of wide-range flow.

[0013] To solve the above technical problems, the following technical solutions are adopted in the present application: the present application provides a large-range variable area ratio vector exhaust device, comprising: a transition section, a guide vane section, and a rotating afterbody.

[0014] The guide vane section is connected to the outlet of the transition section, and the rotating afterbody is connected to the rear side of the transition section.

[0015] When switching between different working states including vertical take-off and landing state, transition state, and flat flying state, the direction of the airflow and the jet angle are adjusted by changing the positions of the guide vane section and the rotating afterbody.

[0016] Further, the transition section is a round-to-square pipeline, the transition section inlet is a circular cross section with a diameter of D, the size of the transition section inlet is determined by the size of the connected power system, and the transition section outlet is a square cross section, and the square cross section area is determined by the required outlet exhaust area of the vertical take-off state outlet.

[0017] Further, the guide vane section is composed of a plurality of guide vanes to form a shutter type square exhaust passage, which facilitates the simplification of the guide vane adjusting mechanism and the flow field structure inside the guide vane.

[0018] The guide vanes are connected at the head and tail to form a closed convergent nozzle passage lower wall surface in the level flight state.

[0019] The length of the last guide vane of the guide vane section is greater than that of the other guide vanes, and the length of any guide vane is 10 mm longer than the grid spacing, so that the front and rear edges of the guide vanes are tightly connected to each other.

[0020] Further, the guide vanes are NACA0009 airfoils and can be deflected by 0°-90°.

[0021] Further, the rotating afterbody is composed of a circular arc section and a straight section.

[0022] The straight section is a bridge curve with a length of L, and the head and tail of the bridge curve are tangent to the circular arc section and the horizontal line to form the rear side wall surface of the transition section in the vertical take-off state.

[0023] Further, in the level flight state, the rotating afterbody is placed at an angle θ to the rear as the convergent nozzle passage upper wall surface, and the last guide vane of the guide vane section forms a convergent nozzle passage.

[0024] Further, the size of the convergent nozzle passage formed by the rotating afterbody and the guide vane section is determined by the required outlet exhaust area of the aircraft in the level flight state.

[0025] Further, the positions of the convergent nozzle passage, the transition section and the rotating afterbody satisfy the following geometric constraints:

[0026] (H+h)·tan θ+R=h / cos θ

[0027] R=0.2D

[0028] Where H is the height of the convergent nozzle passage, h is the longitudinal distance from the center of the rotating afterbody to the end point of the bridge curve in the level flight state, and R is the radius of the circular arc section of the rotating afterbody.

[0029] Further, in the vertical take-off state, the guide vanes of the guide vane section are vertically downward, the transition section guides the airflow to the front edge of the guide vane, and the airflow is vertically downward to generate lift.

[0030] In the transition state, the guide vanes of the rotating afterbody and the guide vane section are deflected by the same angle to form a vector exhaust channel;

[0031] In the horizontal flight state, the front and rear edges of the guide vanes of the guide vane section overlap to form a convergent nozzle channel lower wall, and the rotating afterbody serves as the upper wall of the convergent nozzle channel, and the airflow is accelerated and ejected in the convergent nozzle channel formed by the guide vane section and the rotating afterbody to generate horizontal thrust.

[0032] The beneficial effects of the present application are:

[0033] 1. Compared with the existing vector nozzle scheme, the technical scheme of the present application realizes continuous adjustable deflection of airflow from 0° to 90°, overcomes the limitation of limited deflection angle (±45°) of the traditional scheme, and significantly improves the maneuverability and adaptability of the aircraft. At the same time, the present application can realize an outlet area ratio as high as 3.8 in the vertical take-off and landing state and the horizontal flight state, effectively cope with the large flow change from vertical take-off to horizontal flight, and ensure the stability and efficiency of the aircraft in different flight states. In addition, the total pressure recovery coefficient of the present application is as high as 0.98, which is better than the traditional vector nozzle scheme, effectively reduces the energy loss, and improves the thrust, providing stronger power for the aircraft. The present application is suitable for vertical take-off and landing aircraft, and can meet the requirements of airflow direction, ejection angle and outlet area in vertical take-off, transition state and horizontal flight state, providing important technical support for the development of vertical take-off and landing aircraft BRIEF DESCRIPTION OF DRAWINGS

[0034] For ease of illustration, the present application is described in detail by the following specific embodiments and drawings.

[0035] Figure 1 is a three-dimensional aerodynamic modeling schematic diagram of a large-range variable-area-ratio vector exhaust device provided by an embodiment of the present application in a vertical take-off and landing state;

[0036] Figure 2 is a three-dimensional aerodynamic modeling schematic diagram of a large-range variable-area-ratio vector exhaust device provided by an embodiment of the present application in a transition state;

[0037] Figure 3 is a three-dimensional aerodynamic modeling schematic diagram of a large-range variable-area-ratio vector exhaust device provided by an embodiment of the present application in a horizontal flight state;

[0038] Figure 4 is a geometric relationship schematic diagram of a large-range variable-area-ratio vector exhaust device provided by an embodiment of the present application.

[0039] In the figure: 1, transition section; 2, rotating afterbody; 3, guide vane section; 4, bridging curve. DETAILED DESCRIPTION

[0040] The following are specific embodiments of the present application and further describe the technical solutions of the present application in conjunction with the drawings, but the present application is not limited to these embodiments; in the following description, specific details such as specific configurations and components are provided only to help a comprehensive understanding of the embodiments of the present application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. In addition, in order to be clear and concise, the description of known functions and structures is omitted.

[0041] It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0042] As Figures 1-4 shown in a specific embodiment of a large-area variable-area ratio vector exhaust device, comprising: a transition section 1, a guide vane section 3 and a rotating afterbody 2, the guide vane section 3 is connected with the outlet of the transition section 1, and the rotating afterbody 2 is connected with the rear side of the transition section 1, and the rotating afterbody 2 realizes the conversion of the vertical take-off state, the transition state and the flat flight state of the exhaust device.

[0043] Specifically, the transition section 1 is a round-to-square pipe, which converts the airflow of circular cross section to square cross section to adapt to the large outlet area required in the vertical take-off state. The guide vane section 3 is composed of several deflectable guide vanes, which can realize a deflection of 0°-90°, for adjusting the airflow direction. The rotating afterbody 2 is composed of a circular arc section and a straight section, which serves as the rear side wall of the transition section in the vertical take-off state, and forms a converging nozzle channel with the guide vane section 3 in the flat flight state to generate horizontal thrust.

[0044] Specifically, when converting between different working states including the vertical take-off state, the transition state and the flat flight state, the airflow direction and the jet angle are adjusted by changing the positions of the guide vane section 3 and the rotating afterbody 2.

[0045] Specifically, the device adjusts the airflow direction and the jet angle by changing the positions of the guide vane section 3 and the rotating afterbody 2, thereby meeting the requirements of different flight states.

[0046] Vertical take-off state: the guide vanes are vertically downward, the transition section 1 guides the airflow to the leading edge of the guide vanes, and the airflow is vertically downward along the guide vanes to generate lift.

[0047] Transition state: the rotating afterbody 2 and the guide vane section 3 are deflected by the same angle at the same time, forming a vector exhaust channel, so that the direction of the airflow changes.

[0048] Flat flight state: the guide vane section 3 forms a converging nozzle channel lower wall by overlapping the head and tail of the guide vane section 3, and the rotating afterbody 2 serves as the upper wall, and the airflow is accelerated and ejected in the converging nozzle channel to generate horizontal thrust.

[0049] In other preferred embodiments, the transition section 1 is a round-to-square pipeline, the transition section 1 inlet is a circular cross-section with a diameter of D, the size of the transition section 1 inlet is determined by the size of the connected power system, the transition section 1 outlet is a square cross-section, the area of the square cross-section is determined by the required outlet exhaust area in the vertical take-off state, the rear side of the transition section 1 is connected to the rotating rear body 2, and the vertical take-off state is the rear side wall surface of the transition section 1.

[0050] In other preferred embodiments, the guide vane section 3 is a shutter-shaped square exhaust passage composed of a plurality of guide vanes, and the square passage facilitates the simplification of the guide vane adjustment mechanism and the flow field structure inside the guide vane; the guide vane can achieve a deflection of 0°-90°, the guide vane is a NACA0009 airfoil with an appropriate thickness, the guide vanes at the head and tail of the plane state are mutually overlapped to form a convergent nozzle passage lower wall surface, and the length of the guide vanes is 10 mm longer than the grid spacing to facilitate the mutual close overlap of the front and rear edges of the guide vanes; the length of the last guide vane of the guide vane section 3 is greater than that of the other guide vanes to form a long enough horizontal jet passage.

[0051] In other preferred embodiments, the rotating rear body 2 is composed of a circular arc section and a straight section, the radius R of the circular arc section is 0.2D, and the circular arc section is used to meet the rotation requirement of the rotating rear body 2; the straight section is used as the rear side wall surface of the transition section 1 to constrain the airflow; the straight section is a bridge curve 4 with a length L, and the ends of the bridge curve 4 are tangent to the circular arc section and the horizontal line; in the horizontal state, the rotating rear body 2 is placed with a certain angle θ backward as a convergent nozzle passage upper wall surface, and forms a convergent nozzle passage with the last guide vane of the guide vane section 3 to avoid the formation of a supersonic region.

[0052] Specifically, in the horizontal state, the rotating rear body 2 is placed with an angle θ backward as a convergent nozzle passage upper wall surface, and forms a convergent nozzle passage with the last guide vane of the guide vane section 3.

[0053] Specifically, the size of the convergent nozzle passage formed by the rotating rear body 2 and the guide vane section 3 is determined by the required exhaust area of the present exhaust device in the horizontal state, the height of the convergent nozzle passage is H, and the longitudinal distance from the center of the rotating rear body 2 to the end point of the bridge curve 4 is h in the horizontal state; in order to make the rotating rear body 2 and the guide vanes behind it connected head-to-tail and maintain the sealing of the present exhaust device in the vertical take-off state, the positions of the convergent nozzle passage, the transition section 1 and the rotating rear body 2 satisfy the set geometric constraints: (H+h)·tan θ+R=h / cos θ.

[0054] Wherein, H is the height of the convergent nozzle passage, h is the longitudinal distance from the center of the rotating rear body to the end point of the bridge curve in the horizontal state; R is the radius of the circular arc section of the rotating rear body.

[0055] As shown in Figures 1-3 The present embodiment provides an exhaust method of a large-range variable-area ratio vector exhaust device, comprising the following steps:

[0056] In the vertical take-off state, the guide vanes of the guide vane section 3 are vertically downward, the transition section 1 guides the airflow to the leading edge of the guide vanes, and the airflow is vertically downward discharged along the guide vanes to generate lift; in the transition state, the rotating rear body 2 and the guide vanes of the guide vane section 3 are deflected by the same angle, forming a vector exhaust channel; in the horizontal flight state, the leading edge and the trailing edge of the guide vanes of the guide vane section 3 overlap to form the lower wall surface of the convergent nozzle channel, and the rotating rear body 2 serves as the upper wall surface of the convergent nozzle channel, and the airflow is accelerated and discharged in the convergent nozzle channel formed by the guide vane section 3 and the rotating rear body 2 to generate horizontal thrust.

[0057] Specifically, through the design of the embodiment, the embodiment can not only realize continuous adjustable deflection of the airflow from 0°-90°, ensure that the aircraft can maintain good aerodynamic performance and generate sufficient thrust in different flight states, but also has an outlet area ratio of 3.8 in the vertical take-off and horizontal flight states, which can adapt to large flow changes from vertical take-off to horizontal flight; in addition, the high total pressure loss coefficient of the embodiment is greater than 0.98, the aerodynamic performance is good, and a large thrust can be generated in the vertical take-off and horizontal flight states.

[0058] It should be noted that the terms used herein are only intended to describe specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form, unless the context clearly indicates otherwise, and it should also be understood that, when the terms "comprise" and / or "include" are used in the specification, there is a feature, step, work, device, component and / or combination thereof.

[0059] In the description of the present application, it should be understood that the terms "upper", "lower" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0060] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0061] Those skilled in the art to which the present application belongs can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, but will not deviate from the spirit of the present application or exceed the scope defined by the appended claims.

Claims

1. A large-range variable area ratio vector exhaust device, characterized in that: include: A transition section (1), a guide vane section (3) and a rotating rear body (2); The guide vane section (3) is connected to the outlet of the transition section (1), and the rotating rear body (2) is connected to the rear side of the transition section (1); When switching between different working states including a vertical take-off and landing state, a transition state and a level flight state, the airflow direction and the injection angle are adjusted by changing the positions of the guide vane segment (3) and the rotating rear body (2); The rotating rear body (2) is composed of an arc segment and a straight segment; The straight section is a bridge curve (4) of length L, which is tangent to the arc section and the horizontal line at both ends, forming the rear side wall of the transition section (1) in the vertical take-off and landing state; In the level flight state, the rotating rear body (2) is tilted backward at an angle θ and is placed as the upper wall surface of the converging nozzle channel, forming the converging nozzle channel with the tail guide vane of the guide vane section (3).

2. A large-range variable area ratio vector exhaust device according to claim 1, characterized in that The transition section (1) is a circular-to-square pipeline. The inlet of the transition section (1) is a circular cross-section with a diameter of D. The size of the inlet of the transition section (1) is determined by the size of the connected power system. The outlet of the transition section (1) is a square cross-section. The area of ​​the square cross-section is determined by the outlet exhaust area required for the vertical take-off and landing state.

3. The large-range variable area ratio vector exhaust device according to claim 1, characterized in that: The guide vane section (3) is a louver-shaped square exhaust passage formed by a plurality of guide vanes, and the square exhaust passage facilitates the simplification of the guide vane adjustment mechanism and the flow field structure inside the guide vane; The guide vanes overlap each other end to end in a level flight state to form a closed lower wall surface of the convergent nozzle channel; The length of the last guide vane of the guide vane section (3) is greater than that of the other guide vanes. At the same time, the length of any guide vane is 10 mm longer than the grid pitch, so that the leading and trailing edges of the guide vanes can overlap closely with each other.

4. A large-range variable area ratio vector exhaust device according to claim 3, characterized in that: in, The guide vane is a NACA0009 airfoil and can be deflected by 0°-90°.

5. The large-range variable area ratio vector exhaust device according to claim 1, characterized in that: The size of the converging nozzle channel formed by the rotating rear body (2) and the guide vane section (3) is determined by the outlet exhaust area required for the aircraft in a level flight state.

6. The large-range variable area ratio vector exhaust device according to claim 1, characterized in that: The positions of the converging nozzle channel, the transition section (1) and the rotating rear body (2) satisfy the following geometric constraints: ， ， Wherein, H is the height of the converging nozzle channel, h is the longitudinal distance from the center of the rotating rear body (2) to the end point of the bridging curve (4) in the level flight state; and R is the radius of the arc segment of the rotating rear body (2).

7. An exhaust method for a large-range variable area ratio vector exhaust device according to any one of claims 1 to 6, characterized in that: In the vertical take-off and landing state, the guide vanes of the guide vane section (3) are vertically downward, and the transition section (1) guides the airflow to the leading edge of the guide vane, and the airflow is discharged vertically downward along the guide vane to generate lift; In the transition state, the guide vanes of the rotating rear body (2) and the guide vane section (3) are deflected at the same angle simultaneously to form a vector exhaust channel; In the level flight state, the leading and trailing edges of the guide vanes of the guide vane section (3) overlap each other to form the lower wall of the converging nozzle channel, and the rotating rear body (2) serves as the upper wall of the converging nozzle channel. The airflow is accelerated and ejected in the converging nozzle channel formed by the guide vane section (3) and the rotating rear body (2) to generate horizontal thrust.

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