CN114348242A - Variable-drift-diameter duct structure and aircraft - Google Patents

Abstract

The invention relates to the technical field of duct structures for aircraft, in particular to a duct structure with a variable diameter and an aircraft. The duct structure includes: an outer duct section and an inner duct section, and the outer duct section and the inner duct section are distributed at intervals The end-to-end splicing is closed to form a ring, and a duct is formed on the inner side; the duct support structure is connected to the outer duct section; wherein, the outer duct section can slide relative to the inner duct section, and the duct The support structure is arranged to drive adjacent sections of the outer ducts to approach or move away from each other, so as to increase or decrease the diameter of the ducts. The duct structure of the present invention is a retractable type, which can change the diameter in the duct. After the ducted rotor system has a variable diameter, it can provide rich and variable lift and thrust performance, so that the aircraft has higher maneuverability. , adapt to more complex flight conditions.

Description

Variable diameter ducted structure and aircraft

technical field

The invention relates to the technical field of duct structures for aircraft, in particular to a duct structure with a variable diameter and an aircraft.

Background technique

The lift device or power device of an aircraft with a ducted structure can obtain higher lift efficiency or power performance due to the optimization of the flow field of the ducted wall. It has already been used in the propeller power devices of rotary-wing aircraft and fixed-wing aircraft. Wide range of applications.

In engineering practice, rotorcraft with large diameter rotors can obtain larger absolute lift and achieve flight performance such as vertical take-off and landing, hovering, etc. However, the larger diameter of the rotors restricts the maximum level flight speed of the aircraft, which cannot be obtained. higher flight speed.

However, in order to obtain the best power performance at high cruising speed, the propeller-type power plant should not have a large blade diameter, so the maximum pulling force at low speed is limited, making it difficult for the aircraft to achieve vertical take-off and landing maneuvers, which must rely on Airports with longer runways to complete takeoffs and landings.

However, in the prior art, there is only a solution by controlling the diameter of the tail of the duct, which cannot adapt to different sizes of blades, and cannot achieve the above effects. Therefore, a duct structure that can be applied to various flight conditions is urgently needed.

Prior art literature:

Patent Document 1: CN107031850A - Ducted Fan with Variable Geometry and Related Methods

SUMMARY OF THE INVENTION

Aiming at the defects and deficiencies of the duct structure in the prior art, the purpose of the present invention is to control the diameter of the duct to provide rich and variable lift and thrust performance, and to adapt to more complex flight conditions.

A first aspect of the present invention proposes a duct structure with a variable diameter, including:

The outer bypass section and the inner channel section, the outer bypass section and the inner channel section are distributed at intervals, spliced and closed end to end in a ring shape, and a bypass channel is formed on the inner side;

a duct support structure connected to the outer duct section;

Wherein, the outer duct section can slide relative to the inner duct section, and the duct supporting structure is configured to drive the adjacent outer duct sections to approach or move away from each other, so that the passage of the duct decrease or increase in diameter.

Preferably, the duct support structure includes a double-layer shaft and a plurality of telescopic rods arranged on the outer wall of the double-layer shaft, and the second end of each of the telescopic rods is connected to the inner wall of the corresponding outer duct section , the telescopic rod is set to have a stretched position and a compressed position. When the telescopic rod is in the stretched position, the diameter area of the duct is the largest. When the telescopic rod is in the compressed position, the culvert has the largest diameter. The path area of the channel is the smallest.

Preferably, the length of the telescopic rod in the extended position is R, the length of the telescopic rod in the compressed position is r, the curvature of the inner wall surface of the outer duct section is r, and the inner side of the inner duct section is r The curvature of the wall surface is R, the length of the telescopic rod is in the range of Rr, and the diameter of the duct is in the range of πR ² -πr ² .

Preferably, when the duct is in the smallest area, the outer duct sections are connected end to end, and the formed channel has a circular cross-section. When the duct is in the largest area, the outer duct section and the inner duct The segments are connected end to end, and the formed channel cross-sectional shape includes a circular arc with a curvature R and a circular arc with a curvature r distributed at intervals.

1，所述外涵道段至少为八个。Preferably, the length of the telescopic rod in the extended position is R, the length of the telescopic rod in the compressed position is r, and the ratio of the maximum area to the minimum area of the duct is 2:1, where R: r is

1. The number of the outer bypass passages is at least eight.

Preferably, the outer duct section and the inner duct section are both hollow structures with open ends, the edges of both ends of the inner duct section are provided with bulges protruding outward, and the two ends of the outer duct section are provided with protruding portions. The end edge is provided with an inwardly extending shielding part, so that the outer duct section will not come out when the outer wall of the inner duct section slides.

Preferably, the cross-sectional shapes of the outer duct section and the inner duct section are the same, so that the outer duct section can be sleeved on the outer wall of the inner duct section, and the curvature ratio of the outer duct section and the inner duct section is the same is the ratio of the radius of the maximum area to the minimum area of the duct.

Preferably, the telescopic rod includes an inner rod and an outer rod, the outer rod is sleeved on the outer wall of the inner rod, and the cross-sections of the inner rod and the outer rod are streamlined.

Preferably, the double-layer shaft includes an inner shaft and an outer shaft, the inner shaft is rotatably connected to the inner wall of the outer shaft, and the telescopic rod is fixed to the outer wall of the outer shaft.

A second aspect of the present invention provides an aircraft including the variable-diameter duct structure in the above solution.

Compared with the prior art, the advantages of the present invention are:

The duct structure of the present invention is a retractable type, which can change the diameter in the duct. After the ducted rotor system has a variable diameter, it can provide rich and variable lift and thrust performance, so that the aircraft has higher maneuverability. , adapt to more complex flight conditions.

Different duct paths correspond to different flight states, which can reduce fuel consumption, improve fuel economy, and increase the maximum range and endurance of the aircraft.

Description of drawings

The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures may be represented by the same reference numeral. For clarity, not every component is labeled in every figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings, wherein:

Fig. 1 is the structural representation that the duct structure of the variable diameter shown in the present invention is in the state of maximum diameter;

Fig. 2 is the structural representation that the duct structure of the variable diameter shown in the present invention is in the minimum diameter state;

Fig. 3 is the front view of the duct structure of the variable diameter shown in the present invention in the state of maximum diameter;

Fig. 4 is the front view of the duct structure of the variable diameter shown in the present invention in the minimum diameter state;

FIG. 5 is a schematic cross-sectional structure diagram of the variable-diameter duct structure shown in the present invention in a state of maximum diameter.

Detailed ways

In order to better understand the technical content of the present invention, specific embodiments are given and described below in conjunction with the accompanying drawings.

As described in the background art, an aircraft can obtain a larger lift force when a rotor with a larger diameter is used, but the flight speed is restricted. A blade with a smaller diameter has a higher speed, but the lift force is limited. A ducted structure adapted to blades of different diameters to improve the flow field of the blades and provide richer lift and thrust performance.

1-4, the first aspect of the present invention proposes a variable diameter duct structure, which can be used in aircraft lift or power devices such as rotors, propellers, and fans with variable diameter requirements. It mainly includes the outer duct section 5 and the inner duct section 4. As shown in Figure 1-2, the distribution of the interval between the outer duct section 5 and the inner duct section 4 is spliced and closed in a ring shape, and a duct is formed on the inside.

Further, the duct support structure is connected to the outer duct section 5, and the outer duct section 5 can slide relative to the inner duct section 4, and the duct support structure is arranged to drive the adjacent outer duct sections 5 to approach each other or away, so that the diameter of the duct is reduced or increased.

As shown in Fig. 1, when the adjacent outer duct sections 5 are far away from each other, the diameter of the duct increases, so that a larger diameter blade can be accommodated, a larger lift force can be obtained, and a vertical take-off and landing requirement can be met. . As shown in Figure 2, when the adjacent outer duct sections 5 are close to each other, the diameter of the duct decreases, so that smaller diameter blades can be accommodated, faster speed can be obtained, and the requirement of fast flight can be met. .

As shown in Figure 5, the outer duct section 5 and the inner duct section 4 have a duct wall section shape that conforms to the principle of fluid mechanics, and have the aerodynamic properties of a duct-like structure, thereby providing an improved flow field for the internal rotor or propeller structure. effect.

Specifically, the duct is composed of an outer duct section 5 and an inner duct section 4 distributed at intervals along the circumferential direction, and each of the outer duct section 5 and the inner duct section 4 has a complete duct section shape, so that the duct section along the duct section Good aerodynamics can be achieved by the airflow passing in the direction. Among them, the outer duct section 5 is slightly larger than the inner duct section 4, and can be set on the outside of the inner duct section 4.

When the structural sections of the duct wall are combined into a whole duct, the outer duct section 5 and the inner duct section 4 are staggered. When the outer duct section 5 and the inner duct section 4 are all unfolded, the duct has the maximum diameter. When the power device can obtain the maximum pulling force, it corresponds to the flight states such as vertical take-off and landing, hovering, etc.; when the duct wall shrinks, the outer duct section 5 gradually overlaps the outer side of the inner duct section 4, and the duct diameter gradually shrinks. To achieve stepless change; until the inner section 4 is all closed inside the outer section 5, the duct obtains the minimum diameter, at this time the power unit can adapt to the maximum flight speed, corresponding to the flight state such as cruise.

Further, as shown in FIGS. 3-4, the duct support structure includes a double-layer shaft and a plurality of telescopic rods 3 arranged on the outer wall of the double-layer shaft, and the second end of each telescopic rod 3 is connected to the corresponding outer duct section. 5, the telescopic rod 3 is set to have a stretched position and a compressed position. When the telescopic rod 3 is in the stretched position, the diameter area of the duct is the largest. When the telescopic rod 3 is in the compressed position, the diameter of the duct is the largest. The smallest area.

Specifically, the length of the telescopic rod 3 in the extended position is R; the length of the telescopic rod 3 in the compressed position is r; , the length of the telescopic rod 3 is in the range of Rr, and the diameter of the duct is in the range of πR ² -πr ² .

Preferably, as shown in Figures 3-4, when the duct is in the smallest area, the outer duct section 5 is connected end to end, and the formed channel cross-section is circular. When the duct is in the largest area, the outer duct section 5 and The inner channel sections 4 are connected end to end, and the formed channel cross-sectional shape includes a circular arc with a curvature R and a circular arc with a curvature r distributed at intervals.

In an optional embodiment, according to the working requirements of the variable-diameter rotor system, the variable-diameter duct structure needs to provide a duct diameter change rate of 1:2, that is, the duct when the segmented duct walls are fully opened. The cross-sectional area of the inner diameter of the channel is twice that of the fully retracted state of the duct wall. Therefore, the telescopic range requirement of the corresponding telescopic inner strut is

In other embodiments, in order to achieve a larger rate of change in the cross-sectional area of the diameter, the number of socket layers can be increased, such as three layers or four layers, but as the size difference between the duct sections increases, all the In the case of unfolding, it has a great influence on the aerodynamics. Therefore, preferably, the duct section includes two layers, the inner duct section and the outer duct section.

Further, the number of outer bypass sections is preferably larger, and the more segments, the closer to a standard circle, which is more beneficial to the aerodynamic performance, but the structural complexity increases, and the number of inner struts increases correspondingly, which is beneficial to the overall structure. unfavorable. Conversely, the smaller the number of segments, the simpler the structure, but the worse the roundness. Taking structural realization and aerodynamic performance into consideration, an 8-segment structure is currently selected.

The cross-sectional shape of the outer bypass section 5 and the inner channel section 4 is the same, so that the outer bypass section 5 can be set on the outer wall of the inner channel section 4, and the curvature ratio of the outer bypass section 5 and the inner channel section 4 is the largest. The ratio of the radius of the area to the minimum area, so as to ensure that the inner channel section 4 can be retracted into the outer bypass channel section 5.

Further, the outer duct section 5 and the inner duct section 4 are both hollow structures with open ends, the edges of both ends of the inner duct section 4 are provided with bulges 42 that protrude outward, and both ends of the outer duct section 5 are provided with protruding portions 42. The edge is provided with a shielding portion 52 extending inward, so that the outer duct section 5 will not come out when the outer wall of the inner duct section 4 slides.

Further, the telescopic rod 3 includes an inner rod 32 and an outer rod 31, the outer rod 31 is sleeved on the outer wall of the inner rod 32, and the cross-sections of the inner rod 32 and the outer rod 31 are streamlined. The inner rod 32 and the outer rod 31 have a streamlined shape, adopt a sleeve type telescopic structure, and are driven by electric push rods.

Specifically, the inner rod 32 extends outward, driving the outer duct section 5 to expand, the inner duct section 4 is gradually exposed, and the duct diameter becomes larger; the inner rod 32 shrinks, driving the outer duct section 5 to shrink, and the inner duct section 4 is closed at Inside the outer duct section 5, the duct diameter becomes smaller. The telescopic length range of the telescopic rod 3 is: R-r.

5 , the double-layer shaft includes an inner shaft 1 and an outer shaft 2 , the inner shaft 1 is rotatably connected to the inner wall of the outer shaft 2 , and the telescopic rod 3 is fixed to the outer wall of the outer shaft 2 . In this way, the outer bypass section 5 can be supported. The inner shaft 1 is used to install the blades, and when the blades rotate, power is generated.

A second aspect of the present invention provides an aircraft including the variable-diameter duct structure in the above solution.

For example, the aircraft is a tiltrotor aircraft. The tilt-rotor aircraft uses two sets (or four sets) of rotor systems installed in a row. The rotor system can tilt 90 degrees through the tilt axis, so that the rotor can be freely switched between the vertical upward and forward working states, thereby The aircraft has the vertical take-off and landing working mode of the helicopter and the propeller-driven forward flight mode of the fixed-wing aircraft at the same time. The addition of the variable diameter duct system can greatly improve the rotor aerodynamic efficiency of the tilt-rotor aircraft in the two working modes, so that the flight performance and fuel economy are improved.

In an alternative embodiment, a flying car. With the gradual maturity of the control technology of the quadrotor aircraft, the civil-oriented rotary-wing flying car becomes possible. However, the safety of flying cars in general use scenarios is a more prominent problem. A duct system is set on the outside of the rotor, which can not only play a role in safety protection, but also improve the aerodynamic characteristics of the rotor. The variable diameter duct system provides a ducted aerodynamic environment for different scenarios for the lift system of the flying car, which can respectively meet different usage requirements such as vertical take-off and landing and spanning cruise.

In combination with the above embodiments, the duct structure of the present invention is a retractable type, which can change the diameter in the duct. After the ducted rotor system has a variable diameter, it can provide rich and variable lift and thrust performance, so that the aircraft can be improved. It has higher maneuverability and adapts to more complex flight conditions.

Different duct paths correspond to different flight states, which can reduce fuel consumption, improve fuel economy, and increase the maximum range and endurance of the aircraft.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Those skilled in the art to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be determined according to the claims.

Claims (10)

1. a duct structure of variable diameter, is characterized in that, comprises: The outer bypass section and the inner channel section, the outer bypass section and the inner channel section are distributed at intervals, spliced and closed end to end in a ring shape, and a bypass channel is formed on the inner side; a duct support structure connected to the outer duct section; Wherein, the outer duct section can slide relative to the inner duct section, and the duct supporting structure is configured to drive the adjacent outer duct sections to approach or move away from each other, so that the passage of the duct decrease or increase in diameter. 2. The duct structure with variable diameter according to claim 1, wherein the duct support structure comprises a double-layer shaft and a plurality of telescopic rods arranged on the outer wall of the double-layer shaft, each of the The second end of the telescopic rod is connected to the inner wall of the corresponding outer duct section, the telescopic rod is set to have a stretched position and a compressed position, when the telescopic rod is in the stretched position, the ducted The path area is the largest, and when the telescopic rod is in the compressed position, the path area of the duct is the smallest. 3. The variable diameter duct structure according to claim 2, wherein the length of the telescopic rod in the extended position is R, the length of the telescopic rod in the compressed position is r, and the length of the telescopic rod in the compressed position is r. The curvature of the inner side wall of the outer duct section is r, the curvature of the inner side wall of the inner duct section is R, the length of the telescopic rod is Rr, and the diameter area of the duct is πR ² -πr ² . 4. The duct structure with variable diameter according to claim 3, characterized in that, when the duct is in the smallest area, the outer duct sections are connected end to end, and the formed channel cross section is circular, and when When the duct is at the maximum area, the outer duct section and the inner duct section are connected end to end, and the formed channel cross-sectional shape includes spaced arcs with a curvature of R and arcs with a curvature of r. 5 . The variable diameter duct structure according to claim 2 , wherein the length of the telescopic rod in the extended position is R, the length of the telescopic rod in the compressed position is r, and the length of the telescopic rod in the compressed position is r. 6 . The ratio of the maximum area to the minimum area of the duct is 2:1, where R:r is

There are at least eight external bypass sections. 6. The duct structure with variable diameter according to any one of claims 1-5, wherein the outer duct section and the inner duct section are hollow structures with open ends, and the inner duct section is a hollow structure with open ends. The two end edges of the outer duct section are provided with outwardly protruding protrusions, and the two ends of the outer duct section are provided with inwardly extending shielding parts, so that the inner duct section will not come out when the outer wall of the outer duct section slides. 7. The duct structure with variable diameter according to any one of claims 1-5, wherein the outer duct section and the inner duct section have the same cross-sectional shape, so that the outer duct section can be sleeved It is arranged on the outer wall of the inner channel section, and the curvature ratio of the outer channel section and the inner channel section is the radius ratio of the channel at the maximum area and the minimum area. 8 . The variable diameter duct structure according to claim 2 , wherein the telescopic rod comprises an inner rod and an outer rod, the outer rod is sleeved on the outer wall of the inner rod, and the inner rod The cross-section of the outer rod is streamlined. 9 . The variable diameter duct structure according to claim 2 , wherein the double-layer shaft comprises an inner shaft and an outer shaft, the inner shaft is rotatably connected to the inner wall of the outer shaft, and the telescopic shaft The rod is fixed to the outer wall of the outer shaft. 10. An aircraft, characterized in that it comprises the variable diameter duct structure according to any one of claims 1-9.

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