CN114044135A - Method and device for suppressing high-speed pulse noise of helicopter and helicopter - Google Patents
Method and device for suppressing high-speed pulse noise of helicopter and helicopter Download PDFInfo
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- CN114044135A CN114044135A CN202111553455.2A CN202111553455A CN114044135A CN 114044135 A CN114044135 A CN 114044135A CN 202111553455 A CN202111553455 A CN 202111553455A CN 114044135 A CN114044135 A CN 114044135A
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- 238000010998 test method Methods 0.000 claims description 5
- 238000012360 testing method Methods 0.000 claims description 4
- 230000005284 excitation Effects 0.000 claims description 2
- 230000002401 inhibitory effect Effects 0.000 abstract description 13
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C27/00—Rotorcraft; Rotors peculiar thereto
- B64C27/32—Rotors
- B64C27/46—Blades
- B64C27/467—Aerodynamic features
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C23/00—Influencing air flow over aircraft surfaces, not otherwise provided for
- B64C23/005—Influencing air flow over aircraft surfaces, not otherwise provided for by other means not covered by groups B64C23/02 - B64C23/08, e.g. by electric charges, magnetic panels, piezoelectric elements, static charges or ultrasounds
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Abstract
The invention discloses a method and a device for inhibiting high-speed pulse noise of a helicopter and the helicopter, and relates to the technical field of noise control of helicopters. The method and the device for inhibiting the high-speed impulse noise of the helicopter and the helicopter can effectively inhibit the high-speed impulse noise of the rotor wing of the helicopter in each flight state, and have good applicability.
Description
Technical Field
The invention relates to the technical field of helicopter noise control, in particular to a method and a device for inhibiting high-speed pulse noise of a helicopter and the helicopter.
Background
The helicopter has the advantages of vertical take-off and landing, high maneuverability, hovering in the air and the like, so that the helicopter is widely applied to the military and civil fields. However, helicopter noise is one of its major drawbacks. In the civil field, the helicopter with high noise seriously affects the riding comfort of pilots and passengers, thereby directly limiting the application range of the helicopter; in the military field, noise can influence the stealthy performance of the helicopter, and the viability of the helicopter is greatly reduced. Therefore, how to reduce noise increasingly becomes a problem of the key consideration of helicopter design, and relevant research is developed to have important economic benefit and military value.
Rotor aerodynamic noise is the main noise source of helicopters, and can be divided into according to the noise characteristic: thickness noise, load noise, high-speed impulse noise, paddle-vortex interference noise, and broadband noise. When the helicopter flies ahead at a high speed, the moving blade of the rotor wing locally flows at a transonic speed, the blade tip can generate shock waves, when the speed of the blade tip is increased to a certain value, the shock waves on the surface of the blade can be diffused to an ultrasonic speed area outside the blade tip, the phenomenon of delocalization is called, shock wave interference can be spread to a far field, and therefore high-speed pulse noise is generated. Once the helicopter generates high-speed impulse noise, the overall noise level of the helicopter is greatly improved.
At present, the suppression methods for the high-speed pulse noise of the helicopter rotor are few, and the methods for optimizing the aerodynamic shape of a blade tip, controlling the entity bulge, controlling the groove and the like are mainly common. The aerodynamic shape of the blade tip is optimized, such as forward sweep, backward sweep, tapering and the like are adopted to change the blade tip shape so as to delay the generation of shock waves and weaken the intensity of the shock waves, and therefore, the high-speed pulse noise of the rotor wing is reduced. The method for inhibiting the entity bulge comprises the steps of additionally arranging the bulge on the rotor wing tip to control shock waves, changing strong shock waves of the rotor wing tip into lambda waves or weak oblique shock waves, and weakening the shock wave intensity, so that the effect of inhibiting high-speed pulse noise is achieved. The groove control method is characterized in that a groove is formed in the tip of the rotor wing, a porous plate covers the groove, so that airflow after shock can flow to the front of the rotor wing through the groove, pressure before and after the shock is automatically adjusted, the shock strength is reduced, and the effect of reducing high-speed pulse noise is achieved. The methods change the appearance of the rotor wing to a certain extent, influence the aerodynamic performance of the rotor wing, belong to passive control methods, and only have a good control effect in a design state, and when the actual situation deviates from the design state, the control effect is poor. In addition, a method for reducing the rotating speed of the rotor is also used for inhibiting the high-speed pulse noise of the rotor, however, the rotating speed is reduced to be possibly close to the structural frequency of the helicopter to generate resonance, so that a series of means are required to avoid the resonance problem in the aspects of helicopter structural design and rotor rotating speed control, and the difficulty of helicopter design is greatly increased. Therefore, the rotor high-speed impulse noise suppression technology is not mature, and a simpler and more effective suppression method still needs to be developed.
GlezerA proposes a flow control means of synthetic jet (GlezerA, Amitay M. synthetic jets [ J ]. Annual Review of fluid Mechanics,2003,34(1): 503) 529), and researches show that the synthetic jet interacts with a transverse main flow to change the flow direction of the airflow, which is equivalent to changing the shape of an object to realize a virtual pneumatic appearance. Therefore, if the synthetic jet flow is reasonably applied to the surface of the rotor blade tip, a virtual bulge can be formed on the surface of the rotor blade tip, and the effects of weakening blade tip shock waves and inhibiting high-speed pulse noise of the rotor blade are achieved. Therefore, there is a great potential for suppressing high-speed impulse noise of a rotor using synthetic jets.
Disclosure of Invention
The invention provides a method and a device for inhibiting high-speed pulse noise of a helicopter and the helicopter, which are used for solving the problems in the prior art, can effectively inhibit the high-speed pulse noise of a rotor wing of the helicopter in each flight state and have good applicability.
In order to achieve the purpose, the invention provides the following scheme:
the invention provides a method for inhibiting high-speed pulse noise of a helicopter, which is characterized in that at least one synthetic jet flow exciter is embedded in the upper surface of a blade tip, the synthetic jet flow exciter can generate upward jet flow, the jet flow can act with a main flow of a blade to form an aerodynamic profile, when high-speed pulse noise is generated, a shock wave on the blade tip is a noise shock wave, and the opening state and control parameters of the synthetic jet flow exciter are adjusted to change the shape of the aerodynamic profile so as to weaken the intensity of the noise shock wave.
Further, the synthetic jet actuator is arranged in a noise shock wave generating region, and the noise shock wave generating region is a region formed by the positions of the noise shock waves acting on the blade.
Further, the position information of the noise shock wave acting on the blade is obtained through a computational fluid dynamics method.
Further, the position information of the noise shock wave acting on the blade is obtained through a wind tunnel test method.
Furthermore, the position information of the noise shock waves acting on the blades comprises the maximum distance, the minimum distance and the distance from the noise shock waves to the rotor wing rotating shaft.
Further, the control parameters of the synthetic jet actuator include an actuation frequency and an exit momentum coefficient.
Further, in a test stage, adjusting the starting state and the control parameter of each synthetic jet actuator in each different flight state of the helicopter when high-speed impulse noise can be generated to obtain the starting state and the control parameter of the synthetic jet actuator when the high-speed impulse noise is reduced for the first time in each flight state of the helicopter, wherein the starting state and the control parameter of each synthetic jet actuator are respectively a first starting state and a first control parameter at the moment; adjusting each synthetic jet actuator to the first on state and the first control parameter while the helicopter is actually flying.
Further, when the helicopter actually flies, it is first judged whether the flight state of the helicopter is within a condition range for generating the high-speed impulse noise, and if so, each synthetic jet actuator is adjusted to the first on state and the first control parameter.
The invention also provides a device for suppressing the high-speed impulse noise of the helicopter, which comprises at least one synthetic jet actuator embedded in the upper surface of the blade tip, wherein the synthetic jet actuator can generate upward jet flow, the jet flow can act with the main flow of the blade to form an aerodynamic shape, and the shape of the aerodynamic shape can be changed by adjusting the opening state and control parameters of the synthetic jet actuator so as to weaken the intensity of the shock wave when the high-speed impulse noise is generated.
The invention also provides a helicopter which comprises a fuselage, a rotor wing and the device for inhibiting the high-speed impulse noise of the helicopter, wherein the rotor wing is rotatably connected with the fuselage, and the device for inhibiting the high-speed impulse noise of the helicopter is embedded in the upper surface of a blade tip.
Compared with the prior art, the invention has the following technical effects:
the invention provides a method and a device for inhibiting high-speed pulse noise of a helicopter and the helicopter. When the helicopter flies at a high speed to generate high-speed impulse noise, the opening state and the control parameters of each synthetic jet actuator are adjusted to adjust the state of a virtual bulge, and the virtual bulge can weaken the intensity of noise shock waves and reduce the delocalization phenomenon of rotor blade tip shock waves, so that the effect of inhibiting the high-speed impulse noise of the helicopter is realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Description of reference numerals:
FIG. 1 is a schematic diagram of a synthetic jet actuator provided by the invention;
FIG. 2 is a schematic view of the aerodynamic profile provided by the invention;
FIG. 3 is a schematic diagram of the location of a noise shock provided by the present invention;
FIG. 4 is an illustration of the synthetic jet actuator position provided by the invention.
Description of reference numerals: 1. a synthetic jet actuator; 2. aerodynamic shape; 3. a noise shock wave; 4. a blade.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a method and a device for suppressing high-speed impulse noise of a helicopter and the helicopter, which are used for solving the problems in the prior art, can effectively suppress the high-speed impulse noise of a rotor wing in each flight state and have good applicability.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Example 1
The embodiment provides a method for suppressing high-speed impulse noise of a helicopter, as shown in fig. 1-4, at least one synthetic jet exciter 1 is embedded in the upper surface of a blade tip, the synthetic jet exciter 1 can generate upward jet flow, the jet flow can act with a main flow of a blade to form an aerodynamic profile 2, a shock wave on the blade tip is a noise shock wave 3 when the high-speed impulse noise is generated, and the opening state and control parameters of the synthetic jet exciter 1 are adjusted to change the shape of the aerodynamic profile 2 so as to weaken the intensity of the noise shock wave 3.
The aerodynamic shape 2 is equivalent to a virtual bulge, when the helicopter flies at a high speed to generate high-speed pulse noise, the opening state and the control parameters of the synthetic jet actuator 1 are adjusted to adjust the state of the virtual bulge, and the virtual bulge can weaken the intensity of a noise shock wave 3 and reduce the delocalization phenomenon of a rotor wing tip shock wave, so that the effect of restraining the high-speed pulse noise of the helicopter is realized.
Using Computational Fluid Dynamics (CFD) or wind tunnelsThe test method obtains the flow field state of the rotor wing under different flight states. Judging whether the blade tip shock wave reaches the condition of generating high-speed pulse noise, if so, recording the position information of the noise shock wave 3 acting on the blades 4, namely the minimum distance L between the noise shock wave 3 and the rotor wing rotating shaftLiAnd a maximum distance LRiAnd a distance C from the leading edge of the blade 4iAs shown in fig. 3, the positions of the noise shocks 3 form a noise shock generation area a, the side lengths of the noise shock generation area a are L and C, respectively, and L is Max (L ═ Max) (LRi)-Min(LLi)，C＝Max(Ci)-Min(Ci) Where Min (L)Li) And Max (L)Ri) L respectively representing the noise shock wave 3 in each flight regimeLiMinimum value of (1) and LRiMaximum value of (C), Min (C)i) And Max (C)i) Respectively showing the distance C from the noise shock wave 3 to the front edge of the blade 4 in each flight stateiMinimum and maximum values of.
The noise shock wave generation region a is equally divided into m × n grids along the radial direction and the chord direction, and one synthetic jet actuator 1 is placed on each grid point to form a synthetic jet actuator array. In order to ensure that the jet can cover the whole noise shock wave generation area a, as shown in fig. 4, one more layer of synthetic jet actuators 1 is arranged outside the noise shock wave generation area a, that is, the number of the arranged synthetic jet actuators 1 is (m +2) × (n + 2).
In the test stage, the flow field state of the rotor wing in different flight states is obtained by using a Computational Fluid Dynamics (CFD) or wind tunnel test method. Judging whether the rotor blade tip shock wave reaches the condition of generating high-speed impulse noise, if so, recording the flight state of the rotor, and the azimuth angle (psi) range psi of the blades 4 when the high-speed impulse noise is generatedmin～ψmaxAnd the position information of the noise shock waves 3 acting on the blade 4, i.e. the minimum distance L between each noise shock wave 3 and the rotation axisLiAnd a maximum distance LRiAnd a distance C from the leading edge of the blade 4iAs shown in fig. 3, to the database.
In the test stage, in each different flight state of the helicopter (obtained by using computational fluid dynamics or wind tunnel test method) when high-speed impulse noise can be generated, the opening state and the control parameter of each synthetic jet actuator 1 are adjusted, specifically, the control parameter includes excitation frequency and outlet momentum coefficient, the opening state and the control parameter of each synthetic jet actuator 1 when the high-speed impulse noise is reduced are obtained in each flight state of the helicopter for the first time, at the moment, the opening state and the control parameter of each synthetic jet actuator are respectively the first opening state and the first control parameter, and the flight state of the helicopter, the first opening state and the first control parameter of each synthetic jet actuator on each azimuth angle blade 4 are stored in a database.
When the helicopter actually flies, whether the flight state of the helicopter is in the condition range of generating high-speed impulse noise in the database is judged, if so, a first opening state and a first control parameter of the blades at each azimuth angle corresponding to the flight state of the helicopter in the database are called, each synthetic jet actuator 1 is adjusted to the first opening state and the first control parameter, the aerodynamic shape 2 is adjusted, the intensity of the noise shock wave of the helicopter is reduced, the high-speed impulse noise is further reduced, and finally the effect of reducing the overall noise of the helicopter is achieved.
Example 2
The embodiment provides a device for suppressing high-speed impulse noise of a helicopter, which comprises at least one synthetic jet actuator 1 embedded on the upper surface of a blade tip, wherein the synthetic jet actuator 1 can generate upward jet, the jet can act with the main flow of a blade 4 to form an aerodynamic profile 2, and the shape of the aerodynamic profile 2 can be changed by adjusting the opening state and control parameters of the synthetic jet actuator 1 so as to weaken the intensity of a shock wave when the high-speed impulse noise is generated.
Example 3
The embodiment provides a helicopter, which comprises a fuselage, a rotor and the device for suppressing the high-speed impulse noise of the helicopter in the embodiment 2, wherein the rotor is rotatably connected with the fuselage, and the device for suppressing the high-speed impulse noise of the helicopter is embedded in the upper surface of a blade tip. The opening state and the control parameters of the synthetic jet actuator 1 are adjusted, and the effect of reducing the high-speed pulse noise of the helicopter is achieved.
The principle and the implementation mode of the present invention are explained by applying specific examples in the present specification, and the above descriptions of the examples are only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.
Claims (10)
1. A method for suppressing high-speed impulse noise of a helicopter is characterized by comprising the following steps: embedding at least one synthetic jet actuator on the upper surface of a blade tip, wherein the synthetic jet actuator can generate upward jet, the jet can act with a main flow of a blade to form a pneumatic profile, when high-speed pulse noise is generated, a shock wave on the blade tip is a noise shock wave, and the opening state and control parameters of the synthetic jet actuator are adjusted to change the shape of the pneumatic profile so as to weaken the intensity of the noise shock wave.
2. A method of suppressing helicopter high speed impulse noise according to claim 1, characterized by: the synthetic jet exciter is arranged in a noise shock wave generating area, and the noise shock wave generating area is an area formed by the positions of all the noise shock waves acting on the blade.
3. A method of suppressing helicopter high speed impulse noise according to claim 2, characterized by: and obtaining the position information of the noise shock wave acting on the blade by a computational fluid dynamics method.
4. A method of suppressing helicopter high speed impulse noise according to claim 2, characterized by: and obtaining the position information of the noise shock wave acting on the blade by a wind tunnel test method.
5. A method of suppressing helicopter high speed impulse noise according to claim 3 or 4, characterized by: the position information of the blade acted by the noise shock waves comprises the maximum distance, the minimum distance and the distance from the noise shock waves to the rotor rotating shaft to the front edge of the blade.
6. A method of suppressing helicopter high speed impulse noise according to claim 1, characterized by: the control parameters of the synthetic jet actuator include an excitation frequency and an outlet momentum coefficient.
7. A method of suppressing helicopter high speed impulse noise according to claim 1, characterized by: in a test stage, adjusting the starting state and the control parameter of each synthetic jet actuator in each different flight state of the helicopter when high-speed impulse noise can be generated to obtain the starting state and the control parameter of each synthetic jet actuator when the high-speed impulse noise is reduced for the first time in each flight state of the helicopter, wherein the starting state and the control parameter of each synthetic jet actuator are respectively a first starting state and a first control parameter; adjusting each synthetic jet actuator to the first on state and the first control parameter while the helicopter is actually flying.
8. A method of suppressing helicopter high speed impulse noise according to claim 7, characterized by: when the helicopter actually flies, firstly, whether the flying state of the helicopter is in the condition range of generating the high-speed impulse noise is judged, and if so, each synthetic jet actuator is adjusted to the first starting state and the first control parameter.
9. A device for suppressing high-speed impulse noise of a helicopter is characterized in that: the blade comprises at least one synthetic jet actuator embedded in the upper surface of a blade tip, the synthetic jet actuator can generate upward jet flow, the jet flow can act with a main flow of a blade to form an aerodynamic shape, and the shape of the aerodynamic shape can be changed by adjusting the opening state and control parameters of the synthetic jet actuator so as to weaken the intensity of a shock wave when high-speed impulse noise is generated.
10. A helicopter, characterized by: the device for suppressing the high-speed impulse noise of the helicopter comprises a fuselage, a rotor and the device for suppressing the high-speed impulse noise of the helicopter, wherein the rotor is rotatably connected with the fuselage, and the device for suppressing the high-speed impulse noise of the helicopter is embedded in the upper surface of a blade tip.
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| CN202111553455.2A CN114044135A (en) | 2021-12-17 | 2021-12-17 | Method and device for suppressing high-speed pulse noise of helicopter and helicopter |
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| CN202111553455.2A CN114044135A (en) | 2021-12-17 | 2021-12-17 | Method and device for suppressing high-speed pulse noise of helicopter and helicopter |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114537658A (en) * | 2022-04-01 | 2022-05-27 | 南京航空航天大学 | Dynamic response variable-speed rotor noise reduction device, method and system |
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2021
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