A high-efficiency low-resistance air intake device for vertical take-off and landing aircraft

Abstract

The present invention discloses a high-efficiency and low-resistance air intake device for a vertical take-off and landing aircraft, comprising a power section and an air intake device, wherein the air intake device is located on the upper side of the power section to capture airflow, and the air intake device comprises an air intake section, a flow stabilization section and an inner channel drag reduction plate, wherein the air intake section is located on the upper side of the power section, and the airflow is efficiently captured and decelerated by the air intake section, and then the flow stabilization section is used to ensure that the flow direction of the airflow meets the working conditions of the ducted fan, and a trapped vortex is generated at the rear side of the inner channel drag reduction plate to form an aerodynamic wall surface to reduce the turning angle of the airflow at the rear lip of the air intake device to avoid flow separation at this location and cause excessive overflow resistance, thereby ensuring that the air intake device has a compact structure, and that the ducted fan can ensure high-efficiency air intake in various states from vertical take-off and landing to horizontal flight without any movable parts, thereby effectively reducing the fuel consumption of the power system and increasing the range and load-bearing capacity of the aircraft.

Description

Technical Field

[0001] The invention relates to the technical field of vertical take-off and landing power systems, and in particular to a high-efficiency low-resistance air intake device for a vertical take-off and landing aircraft. Background Art

[0002] Vertical take-off and landing technology can reduce or even completely get rid of the aircraft's dependence on runways, which can greatly reduce the aircraft's demand for facilities in the take-off and landing area. Therefore, compared with conventional fixed-wing aircraft, vertical take-off and landing aircraft have stronger adaptability to the working area, and have a large application space under the conditions of small take-off and landing areas or complex terrain environments (remote mountainous areas, urban centers, earthquake-stricken areas). With the innovation of the concept of vertical take-off and landing aircraft abroad, the main technical forms currently include the following three types: 1) Compound helicopter: When taking off and landing vertically, the top rotor is used to generate traction like a helicopter, and in the case of level flight, the horizontal engine installed on both sides of the fuselage or the tail is used to generate thrust. Typical models include the X2 high-speed helicopter of Sikorsky in the United States and the X3 helicopter of Eurocopter. 2) Tilt-rotor aircraft: The power direction is changed by the overall rotation of the engine. When taking off and landing and hovering, the engine is nearly vertical to generate upward traction, and when flying horizontally, the engine tilts to nearly horizontal to provide forward power. Typical models include the V-22 Osprey tilt-rotor aircraft in the United States. 3) Fixed-wing aircraft with jet steering: using tiltable vector nozzles and ducted fan structures to achieve vertical take-off and landing and level flight functions, such as the British Harrier fighter and the American F35-B. The power systems of the first two types of vertical take-off and landing aircraft are achieved by combining or changing the rules of using existing turbine engines (turboshafts / turbopropellers). The power system of the third type is a major expansion of advanced military turbofan engines, with vertical lift generated by two-stage counter-rotating lift fans and vector nozzles. After switching to level flight, it retains all the functions of a fighter, so it has received widespread attention.

[0003] In order to achieve vertical take-off and landing, the take-off weight of the aircraft can only be 83% to 85% of the engine thrust, which greatly limits the aircraft's payload and seriously affects the aircraft's fuel capacity and range. In addition, the vertical take-off and landing process consumes a lot of fuel, accounting for 1 / 3 of the aircraft's fuel capacity, which greatly limits the aircraft's combat radius. Whether it is the working power switching of a compound helicopter, the engine steering of a tilt-rotor aircraft, or the lift fan and vector nozzle of a jet-to-fixed-wing aircraft, the above-mentioned existing types of vertical take-off and landing aircraft power systems need to significantly increase the structure and control complexity of the power system to achieve the conversion of vertical and horizontal power output. In the future, vertical take-off and landing aircraft are required to have vertical take-off and landing capabilities while achieving better conversion between vertical take-off and landing and forward flight modes with as little effort as possible, and improve the speed, range, effective load and other comprehensive flight performance. The leapfrog improvement of these capabilities mainly depends on the design method of the adapted new power system and corresponding components. Summary of the invention

[0004] The present invention provides a high-efficiency and low-resistance air intake device for a vertical take-off and landing aircraft, which overcomes the problem that a conventional vertical take-off and landing air intake device requires an additional actuating mechanism and is prone to generate excessive overflow resistance.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an efficient and low-drag air intake device for a vertical take-off and landing aircraft, comprising a power section and an air intake device, wherein the air intake device is located on the upper side of the power section to capture the airflow, and the air intake device comprises an air intake section, a flow stabilization section and an inner channel drag reduction plate, wherein the air intake section is located on the upper side of the power section, the tail end of the air intake section is connected to a ducted fan inlet, and the flow stabilization section is located between the tail end of the air intake section and the inlet of the ducted fan, the inner channel drag reduction plate is located at the inlet of the ducted fan, and both ends of the inner channel drag reduction plate are connected to the inner wall of the inlet of the ducted fan, and the inner channel drag reduction plate is used to ensure air intake in the ground state.

[0006] Preferably, the air intake section is designed as a special-shaped pipeline, and the inlet of the air intake section is tilted backward at an angle greater than 45 degrees to ensure integration with the shape of the power section. The air intake section turns from the inlet and completes a turn of not less than 60 degrees along the flow distance.

[0007] Preferably, the flow distance is the same as the fan radius of the duct.

[0008] Preferably, the cross-sectional shape of the air inlet section transitions from an irregular curve to a regular circle at the outlet of the air inlet section, and is connected to the flow stabilization section.

[0009] Preferably, the air intake section captures the airflow and decelerates the airflow.

[0010] Preferably, the flow stabilizing section realizes the turning of the airflow to ensure that the direction of the airflow meets the working conditions of the ducted fan.

[0011] Preferably, the inner channel drag reducing plate includes an upper surface and a lower surface, the upper surface is controlled by a B-spline curve to generate a blade profile of relative thickness and is laterally stretched to form the inner channel drag reducing plate, and the lower surface is extracted by combining numerical simulation results to intercept the outermost flow surface of the inner channel at the inlet of the ducted fan to ensure the capture of the airflow.

[0012] Preferably, the distance between the trailing edge line of the inner channel drag reducing plate and the air intake section is one third of the fan radius.

[0013] Preferably, the inner channel drag reducing plate will reduce the turning angle of the airflow at the rear lip of the air intake device by generating a trapped vortex on its rear side to form an aerodynamic wall, thereby avoiding overflow resistance caused by flow separation at the rear lip of the air intake device and ensuring efficient air intake in the ground state.

[0014] Preferably, a ducted fan straightening cone is provided at the middle position of the ducted fan inlet, and the ducted fan straightening cone is used to integrate the airflow movement direction during air intake so as to produce smooth aerodynamic straightening.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. In the present invention, the structure of the entire air intake device is very compact and does not require any movable parts, which effectively reduces the structural weight of the air intake device and the transition state control law of the vertical take-off and landing aircraft.

[0017] 2. The inner channel drag reduction plate design adopted in the present invention can effectively take into account the air intake requirements in the ground and level flight states and ensure low overflow resistance, providing a more flexible layout scheme for the power system of the vertical take-off and landing aircraft, which can effectively reduce the fuel consumption of the power system and increase the range and load capacity of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0019] In the attached picture:

[0020] Figure 1 is an oblique view of the air intake device of the present invention;

[0021] Figure 2 is a top view of the air intake device of the present invention;

[0022] Numbers in the figure: 1, power section; 2, air intake section; 3, flow stabilization section; 4, ducted fan inlet; 5, inner channel drag reduction plate; 6, ducted fan straightening cone. DETAILED DESCRIPTION

[0023] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0024] Example: Figure 1 and Figure 2As shown, a high-efficiency, low-resistance air intake device for a vertical take-off and landing aircraft comprises a power section 1 and an air intake device, wherein the air intake device is located on the upper side of the power section 1 to capture airflow, and the air intake device comprises an air intake section 2, a flow stabilizing section 3 and an inner channel drag reducing plate 5, wherein the air intake section 2 is located on the upper side of the power section 1, and the tail end of the air intake section 2 is connected to a ducted fan inlet 4, and the flow stabilizing section 3 is located between the tail end of the air intake section 2 and the ducted fan inlet 4, and a ducted fan straightening cone 6 is provided in the middle of the ducted fan inlet 4, The ducted fan straightening cone 6 is used to integrate the airflow movement direction during air intake so as to produce smooth aerodynamic straightening. The air intake section 2 is designed as a special-shaped pipeline. The inlet of the air intake section 2 is tilted backward at an angle greater than 45 degrees to ensure integration with the shape of the power section 1. The air intake section 2 turns from the inlet and completes a turning angle of not less than 60 degrees along the flow distance. The flow distance is the same as the fan radius of the duct. The cross-sectional shape of the air intake section 2 transitions from an irregular curve to a regular circle at the outlet of the air intake section 2 and is connected to the steady flow section 3. The air intake section 2 realizes the capture of the airflow and deceleration of the airflow, the flow stabilizing section 3 realizes the steering of the airflow to ensure that the flow direction of the airflow meets the working conditions of the ducted fan, the inner channel drag reduction plate 5 is located at the inlet 4 of the ducted fan, and the two ends of the inner channel drag reduction plate 5 are connected to the inner wall of the inlet 4 of the ducted fan, and the inner channel drag reduction plate 5 is used to ensure efficient air intake in the ground state. The inner channel drag reduction plate 5 includes an upper surface and a lower surface. The upper surface is controlled by a B-spline curve to generate a blade profile with a relative thickness of about 0.5, and is pulled laterally. The inner channel drag reducing plate 5 extends to the inner channel drag reducing plate 5, and the lower surface is extracted by combining the numerical simulation results to intercept the outermost flow surface of the inner channel at the inlet 4 of the ducted fan to ensure the capture of the airflow. The distance between the trailing edge line of the inner channel drag reducing plate 5 and the air intake section 2 is about one-third of the fan radius. The inner channel drag reducing plate 5 will generate a trapped vortex on its rear side to form an aerodynamic wall to reduce the turning angle of the airflow at the rear lip of the air intake device, avoid overflow resistance caused by flow separation at the rear lip of the air intake device, and ensure efficient air intake in the ground state.

[0025] As for the specific working principle, the inlet section of the air intake device is arranged on the upper side of the power section 1, and the inlet section is tilted backward to ensure a high degree of integration between the air intake device and the shape of the power section 1. Then the airflow is decelerated and turned in the short-distance air intake section 2 and the steady flow section 3 to ensure the working conditions of the ducted fan. In this process, the small curvature turning of the front section of the air intake section 2 and the suction effect of the ducted fan are used to ensure efficient air intake on the front side of the air intake section 2, which greatly reduces the structural size of the air intake device. On the other hand, in order to ensure that the air intake device does not generate excessive overflow resistance during level flight, an inner channel drag reduction plate 5 is arranged on the rear side of the inner channel of the air intake section 2 to generate a trapped vortex, thereby forming an aerodynamic wall to reduce the turning angle of the airflow at the rear lip of the air intake device to avoid flow separation here and cause excessive overflow resistance, and the drag reduction plate will not have too much impact on the ground state, and can still ensure efficient air intake of the air intake device.

[0026] Finally, it should be noted that the above description is only a preferred example of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-efficiency, low-resistance air intake device for a vertical take-off and landing aircraft, characterized in that: It comprises a power section and an air intake device, the air intake device is located on the upper side of the power section to capture the airflow, the air intake device comprises an air intake section, a flow stabilizing section and an inner channel drag reducing plate, the air intake section is located on the upper side of the power section, the tail end of the air intake section is connected to a ducted fan inlet, and the flow stabilizing section is located between the tail end of the air intake section and the ducted fan inlet, the inner channel drag reducing plate is located at the ducted fan inlet, and both ends of the inner channel drag reducing plate are connected to the inner wall of the ducted fan inlet, and the inner channel drag reducing plate is used to ensure air intake in the ground state; The air intake section is designed as a special-shaped pipeline, and the inlet of the air intake section is tilted backward at an angle greater than 45 degrees to ensure integration with the shape of the power section. The air intake section turns from the inlet and completes a turning angle of not less than 60 degrees along the flow distance; The cross-sectional shape of the air inlet section transitions from an irregular curve to a regular circle at the outlet of the air inlet section, and is connected to the steady flow section; The air intake section captures the airflow and decelerates the airflow; The flow stabilization section realizes the diversion of the airflow, ensuring that the flow direction of the airflow meets the working conditions of the ducted fan; The inner channel drag reducing plate comprises an upper surface and a lower surface, wherein the upper surface is controlled by a B-spline curve to generate a blade profile of relative thickness and is laterally stretched to form the inner channel drag reducing plate, and the lower surface is extracted by combining numerical simulation results to extract the outermost flow surface of the inner channel at the inlet of the ducted fan to ensure the capture of the airflow; The distance between the trailing edge line of the inner channel drag reducing plate and the air inlet section accounts for one third of the fan radius; The inner channel drag reducing plate will reduce the turning angle of the airflow at the rear lip of the air intake device by generating a trapped vortex at its rear side to form an aerodynamic wall, thereby avoiding overflow resistance caused by flow separation at the rear lip of the air intake device.

2. The high-efficiency, low-resistance air intake device for a vertical take-off and landing aircraft according to claim 1, characterized in that: The flow distance is the same as the fan radius of the duct.

3. The high-efficiency, low-resistance air intake device for a vertical take-off and landing aircraft according to claim 1, characterized in that: A ducted fan straightening cone is provided at the middle position of the ducted fan inlet, and the ducted fan straightening cone is used to integrate the airflow movement direction during air intake so as to produce smooth aerodynamic straightening.

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