A device for reducing helicopter blade vortex interference

Abstract

The present invention discloses a device for reducing helicopter blade vortex interference, comprising a hub, on which a plurality of blades are evenly mounted in the circumferential direction, each blade is provided with a telescopic section, the telescopic section is connected to a control device, the control device controls the telescopic section to extend and retract radially during rotation, each blade evenly completes multiple extensions and retractions in each rotation, and the retraction path of each blade is the same. Using active control technology, by accurately adjusting the dynamic length of the blade, the system can effectively increase the distance between the outer end of the blade and the blade tip vortex, thereby greatly reducing the probability of the blade and the wake vortex encountering each other. The pressure fluctuations in the airflow to which the blade is subjected are effectively mitigated, thereby significantly reducing the noise level caused by blade vortex interference. The helicopter can not only better meet the requirements of airworthiness certification, but also improve survivability and mission efficiency in a battlefield environment.

Description

Technical Field

[0001] The invention relates to the technical field of helicopters, and in particular to a device for reducing helicopter blade vortex interference. Background Art

[0002] Helicopters are widely used in various fields of national economy and national defense due to their low requirements for ground take-off and landing conditions. Helicopter rotors mainly provide lift and control torque for changing attitude for helicopters, and the noise they generate directly affects the helicopter's airworthiness certification and survivability on the battlefield.

[0003] The noise generated by the rotor is mainly divided into thickness noise, broadband noise and pulse noise. As the main component of pulse noise, the blade vortex interference noise mainly appears in the landing phase of the helicopter. During this phase, due to the low altitude above the ground, the impact on the ground environment is more severe. Therefore, taking effective measures to reduce the blade vortex interference noise of the helicopter is of great significance to reducing the overall noise of the helicopter. Summary of the invention

[0004] The object of the present invention is to provide a device for reducing helicopter blade vortex interference in order to solve the above-mentioned problems, so as to reduce the interference of the blade vortex generated by the previous blade and thus reduce the noise.

[0005] The technical solution adopted by the present invention is as follows: a device for reducing helicopter blade vortex interference, comprising a hub, on which a plurality of blades are evenly installed in the circumferential direction, each blade is provided with a telescopic section, the telescopic section is connected to a control device, and the control device controls the telescopic section to extend and retract radially during rotation, each blade evenly completes multiple extensions and retractions in each rotation, and the telescopic path of each blade is the same.

[0006] Optionally, the blades extend to their longest point when facing the wind and perpendicular to the wind direction.

[0007] Optionally, an encoder is provided on the hub.

[0008] Optionally, the paddle blades include four pieces, and the interval angle of each extension and retraction of the paddle blades is 90°.

[0009] Optionally, the telescopic section is arranged at the root of the blade, and the blade is connected to the hub via the telescopic section.

[0010] Optionally, the telescopic section includes a connector, a moving electromagnet is provided in the connector, and the moving electromagnet is connected to the control device; a fixed electromagnet is provided on the hub, and the fixed electromagnet is inserted into the moving electromagnet.

[0011] Optionally, the control device is an electrode reversing module, the electrode reversing module is connected to a power supply, and the power supply is also connected to a fixed electromagnet.

[0012] Optionally, the moving electromagnet includes a cavity filled with hydraulic oil, and one end of the fixed electromagnet has a piston, which divides the cavity into a first chamber and a second chamber, and the outsides of the first chamber and the second chamber are connected through an oil pump and a solenoid valve.

[0013] Optionally, the moving electromagnet includes an inner shell and an outer shell, and a first electromagnetic coil is wound between the inner shell and the outer shell.

[0014] Optionally, the fixed electromagnet includes a fixed core and an outer sleeve, and a second electromagnetic coil is wound between the fixed core and the outer sleeve.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0016] 1. The device provided by the present invention is used to reduce the interference of helicopter blade vortices. By using active control technology and accurately adjusting the dynamic length of the blade, the system can effectively increase the distance between the outer end of the blade and the blade tip vortex, thereby greatly reducing the probability of the blade and the wake vortex encountering each other. The pressure fluctuations in the airflow to which the blade is subjected are effectively mitigated, thereby significantly reducing the noise level caused by the interference of blade vortices. The helicopter can not only better meet the requirements of airworthiness certification, but also improve survivability and mission efficiency in battlefield environments.

[0017] 2. The device provided by the present invention for reducing helicopter blade vortex interference adopts an electromagnetic-hydraulic resistance drive system with a fast response speed. When combined with a hydraulic system, it can provide instant response in situations where rapid action is required, reduce mechanical vibration, improve the stability and accuracy of operation, and can withstand harsh working environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0019] Figure 1 Schematic diagram of the blade tip vortex shedding.

[0020] Figure 2 It is a structural schematic diagram of the present invention.

[0021] Figure 3 It is a structural diagram of the blade and telescopic section.

[0022] Figure 4 It is a structural schematic diagram of the telescopic section.

[0023] Figure 5It is a schematic diagram of the structure of a moving electromagnet.

[0024] Figure 6 It is a schematic diagram of the structure of the fixed electromagnet.

[0025] Markings in the figure: 1: hub, 2: blade, 2-1: first blade, 2-2: second blade, 2-3: third blade, 2-4: fourth blade, 3: telescopic section, 31: connector, 32: moving electromagnet, 321: inner shell, 322: outer shell, 323: first electromagnetic coil, 33: fixed electromagnet, 331: fixed core, 332: outer sleeve, 333: piston, 334: second electromagnetic coil, 4: control device, 5: encoder, 6: power supply, 7: shedding vortex, 8: oil pump, 9: solenoid valve. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0027] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0028] Any feature disclosed in this specification, unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0029] A device for reducing helicopter blade vortex interference, such as Figure 2-6 As shown, it includes a hub 1, on which a plurality of blades 2 are evenly installed along the circumferential direction, each of the blades 2 is provided with a telescopic section 3, and the telescopic section 3 is connected to a control device 4. The control device 4 controls the telescopic section 3 to extend and retract radially during rotation, and each of the blades 2 evenly completes multiple extensions and retractions in each rotation, and the telescopic path of each blade 2 is the same.

[0030] Specifically, during the rotation process, the helicopter blades 2 are divided into forward blades 2 and backward blades 2 relative to the forward flight speed. Figure 1As shown, during the forward movement of blade 2, due to the pressure difference between the upper and lower surfaces of blade 2, the downward airflow of the rotor will interact with the vortex generated by the rotor itself, generating a shedding vortex 7 at the tip of blade 2, which will evolve to form a vortex line. During the descent process, the helicopter has a downward velocity component relative to the ground. After the airflow flows in from below, it blows the shedding vortex 7 upward, interfering with the rotating subsequent blade 2. When the subsequent blade 2 passes through these shedding vortices 7, the angle of attack of blade 2 will suddenly change, which causes the airflow separation and vortex shedding on the surface of blade 2. These phenomena will produce strong pressure fluctuations, which will induce blade vortex interference noise, especially when the outer end of blade 2 (greater than 70% radius) is close, this interference is more obvious. In this scheme, by making the latter blade 2 shrink when passing through the shedding vortex 7, increasing the distance from the outer end of blade 2 to the blade tip vortex, the interaction between the vortex generated by the subsequent blade 2 and the previous blade 2 can be reduced, which is an effective way to reduce blade vortex interference noise. In addition, the blade 2 has fewer contact points with the eddy current, and contracting the blade 2 can reduce the impact force of the eddy current on the blade 2, thereby reducing the noise. Among them, by evenly extending and retracting the blade 2 during the rotation cycle of the blade 2, the load of the blade 2 can be better controlled and the overload at certain angles can be reduced. In addition, the extension and retraction path of each blade 2 is the same, which can maintain the dynamic balance of the rotor and prevent additional vibration and performance degradation.

[0031] As another specific embodiment, the blade 2 is extended to its longest point when facing the wind and perpendicular to the wind direction. When the blade 2 is perpendicular to the wind direction, it is in the best position to generate lift. At this time, the blade 2 is extended to its longest point to provide the largest windward area, and the blade 2 can "capture" more air when rotating, thereby generating more lift at the same speed. And when the blade 2 is in a vertical position, the airflow flows along the chord direction of the blade 2. At this time, if the blade 2 is longer, the airflow can be used more effectively to generate lift.

[0032] As another specific embodiment, an encoder 5 is provided on the hub 1. The encoder 5 can provide accurate measurement data of the position of the blade 2, and at the same time provide real-time feedback of the position of the blade 2 to help adjust the extension and retraction state of the blade 2, so as to ensure that the blade 2 is extended to the longest point when facing the wind and perpendicular to the wind direction, thereby improving the efficiency of the rotor system.

[0033] As another specific embodiment, the blade 2 includes four blades, and the interval angle of each extension and retraction of the blade 2 is 90°. Specifically, when the blade 2 is perpendicular to the wind direction and the downwind direction, it extends to the longest point, and begins to retract when passing the longest position. After retracting to a certain angle, it extends again, and extends to the longest again when it is 90° away from the previous longest point. In this solution, the four blades 2 are extended and retracted at the same time, and the blades 2 are kept of equal length, which helps to maintain the rotational balance of the rotor. In addition, the blades 2 can provide consistent aerodynamic performance when rotating, ensuring that the load distribution of the rotor is more uniform throughout the rotation cycle. Specifically, the extension and retraction interval angle can be matched according to the number of blades 2 and the force balance.

[0034] As another specific embodiment, the telescopic section 3 is arranged at the root of the blade 2, and the blade 2 is connected to the hub 1 through the telescopic section 3. The blade root is a key part where the blade 2 is connected to the rotor shaft, and usually has the strongest structural support. The telescopic section 3 is arranged here to utilize the high strength of the blade root area to withstand the stress generated when the blade 2 is extended and retracted. In addition, the telescopic mechanism at the blade root is more easily connected to the internal control system of the helicopter through the rotor shaft, making the telescopic control of the blade 2 more direct and precise.

[0035] As another specific embodiment, the telescopic section 3 includes a connector 31, a moving electromagnet 32 ​​is provided in the connector 31, and the moving electromagnet 32 ​​is connected to the control device 4; a fixed electromagnet 33 is provided on the hub 1, and the fixed electromagnet 33 is inserted into the moving electromagnet 32. The fixed electromagnet 33 is inserted into the fixed electromagnet and moves in the radial direction of the moving electromagnet 32; the fixed electromagnet 33 is relatively fixed to the hub 1, and drives the blade 2 to rotate. By changing the positive and negative polarity of the wire connected to the fixed electromagnet 33, the direction of the magnetic force is changed. At the same time, by changing the polarity of the moving electromagnet 32 ​​through the control device 4, the direction of the magnetic force can also be changed; by matching the magnetic direction of the moving electromagnet 32 ​​and the fixed electromagnet 33, the attraction or repulsion of the two is achieved. In this solution, electromagnetic drive is adopted, the response speed is fast, the blade 2 can be extended and retracted in a short time, it can work under extreme temperature and vacuum environment, and can also provide very precise position control. And there are no complex mechanical gears and connections, so the failure rate is low and the reliability is high. Mechanical drive would likely require complex transmission chains and gearboxes, which would add weight, take up more space, require regular lubrication and maintenance, and would not provide the fast and precise control required.

[0036] As another specific implementation, the control device 4 is an electrode reversing module, the electrode reversing module is connected to a power supply 6, and the power supply 6 is also connected to the fixed electromagnet 33. The electrode reversing module changes the electrode so that the fixed electromagnet 33 and the moving electromagnet 32 ​​on the blade 2 are attracted or separated, and the power supply 6 mainly provides power supply 6 for the fixed electromagnet 33 and the moving electromagnet 32, and different blades 2 can share it.

[0037] As another specific embodiment, the moving electromagnet 32 ​​includes a cavity filled with hydraulic oil, and one end of the fixed electromagnet 33 has a piston 333, and the piston 333 divides the cavity into a first chamber and a second chamber, and the outsides of the first chamber and the second chamber are connected by an oil pump 8 and an electromagnetic valve 9. During the relative movement of the moving electromagnet 32 ​​and the fixed electromagnet 33, the amount of oil in the two chambers of the fixed electromagnet 33 is adjusted by the two-way oil pump 8 and the electromagnetic valve 9 to generate a certain damping, control the movement speed of the blade 2, and thus realize the adjustment function of the blade 2 throughout the rotation cycle. And the electromagnetic drive can provide fast and precise motion control, while the hydraulic system can handle greater forces. Combining the two, the blade 2 can be extended and retracted based on large force and high-precision control. In addition, the hydraulic system can absorb and reduce impact, improve the stability of extension and retraction, and thus reduce the noise caused by pressure fluctuations.

[0038] As another specific embodiment, the moving electromagnet 32 ​​includes an inner shell 321 and an outer shell 322, and a first electromagnetic coil 323 is wound between the inner shell 321 and the outer shell 322. The polarity of the electromagnet generated by the first electromagnetic coil 323 is realized by a polarity switching module. The outer shell 322 is mainly used to fix the blade 2 and fix the first electromagnetic coil 323 at the same time. The coil is wound on the inner shell 321. Furthermore, oil holes are provided at both ends of the inner shell 321 and the outer shell 322, which are mainly used for the hydraulic oil to enter and exit to form motion damping. Sol or foam is filled between the outer shell 322 and the inner shell 321 to fix the first electromagnetic coil 323.

[0039] As another specific embodiment, the fixed electromagnet 33 includes a fixed core 331 and an outer sleeve 332, and a second electromagnetic coil 334 is wound between the fixed core 331 and the outer sleeve 332. The polarity of the second electromagnetic coil 334 is fixed and does not need to be switched. The fixed core 331 and the outer sleeve 332 are used to fix the second electromagnetic coil 334. Among them, sol or foam is filled between the fixed core 331 and the outer sleeve 332 to position the second electromagnetic coil 334. The piston 333 is arranged at one end of the outer sleeve 332, dividing the cavity in the moving electromagnet 32 ​​into two parts, and interacting with the hydraulic oil inside it to form an adjustable liquid resistance during the radius change process of the blade 2.

[0040] The present invention provides an embodiment of a device for reducing helicopter blade vortex interference, and its working process is as follows:

[0041] The entire rotor system includes a blade 2 with an electromagnetic drive. In this system, there are 4 blades (the first blade 2-1, the second blade 2-2, the third blade 2-3, and the fourth blade 2-4). In practice, the number can be increased or decreased as needed. The blade 2 is mounted on the hub 1. The power system drives the blade 2 to rotate through the hub 1, thereby providing lift and control torque for the helicopter. The encoder 5 on the rotating shaft of the hub 1 measures and feedbacks the position of the blade 2 in real time. Without loss of generality, when the second blade 2-2 is perpendicular to the incoming flow axis, its blade tip speed is superimposed on the forward speed to generate the strongest vortex. As the blade 2 rotates, the first blade 2-1 enters its vortex zone. At this time, the electrode commutation module changes the electrode, so that the fixed electromagnet 33 and the moving electromagnet 32 ​​on the first blade 2-1 attract each other, and through the interaction between the oil pump 8 and the solenoid valve 9, a certain damping is generated, so that the first blade 2-1 begins to shrink along the radius at the required speed;

[0042] After the first blade 2-1 avoids the vortex line position of the second blade 2-2, the electrode reversing module changes the electrode again, so that the fixed electromagnet 33 and the moving electromagnet 32 ​​on the first blade 2-1 attract each other, and through the interaction between the oil pump 8 and the solenoid valve 9, a certain damping is generated, so that the first blade 2-1 begins to extend along the radius at the required speed, ensuring that the original length is restored after turning to a position perpendicular to the axis of the incoming flow.

[0043] The present invention is not limited to the above-mentioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A device for reducing helicopter blade vortex interference, characterized in that: The invention comprises a propeller hub (1), wherein a plurality of propeller blades (2) are evenly mounted on the propeller hub (1) along the circumferential direction, each propeller blade (2) is provided with a telescopic section (3), the telescopic section (3) is connected to a control device (4), the control device (4) controls the telescopic section (3) to telescope in the radial direction during rotation, each propeller blade (2) evenly completes multiple telescopic operations in each rotation, and the telescopic path of each propeller blade (2) is the same; When the blade (2) faces the wind and is perpendicular to the wind direction, it is extended to its longest point; the blade (2) comprises four blades, the interval angle of each extension and retraction of the blade (2) is 90°, and each blade (2) is extended and retracted at the same time; The telescopic section (3) comprises a connecting body (31), a moving electromagnet (32) is arranged inside the connecting body (31), and the moving electromagnet (32) is connected to the control device (4); a fixed electromagnet (33) is arranged on the hub (1), and the fixed electromagnet (33) is inserted into the moving electromagnet (32); The moving electromagnet (32) comprises a cavity filled with hydraulic oil, one end of the fixed electromagnet (33) comprises a piston (333), the piston (333) divides the cavity into a first chamber and a second chamber, and the first chamber and the second chamber are connected to each other via an oil pump (8) and a solenoid valve (9); The moving electromagnet (32) comprises an inner shell (321) and an outer shell (322), and a first electromagnetic coil (323) is wound between the inner shell (321) and the outer shell (322); the fixed electromagnet (33) comprises a fixed core (331) and an outer sleeve (332), and a second electromagnetic coil (334) is wound between the fixed core (331) and the outer sleeve (332).

2. The device for reducing helicopter blade vortex interference according to claim 1, characterized in that: An encoder (5) is arranged on the hub (1).

3. The device for reducing helicopter blade vortex interference according to claim 1, characterized in that: The telescopic section (3) is arranged at the root of the blade (2), and the blade (2) is connected to the hub (1) via the telescopic section (3).

4. The device for reducing helicopter blade vortex interference according to claim 1, characterized in that: The control device (4) is an electrode reversing module, the electrode reversing module is connected to a power source (6), and the power source (6) is also connected to a fixed electromagnet (33).

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