Open type rotor engine

Abstract

The invention relates to an open rotor engine. The open rotor engine includes: a rotor blade; the pitch angle of the stator blade can be adjusted through a variable pitch mechanism; the adjustable acoustic liners are arranged on the surfaces of the stator blades; the adjustable acoustic liner comprises a thin film, a perforated plate and a piezoelectric plate, and the piezoelectric plate is arranged on the thin film; the voltage adjusting mechanism is used for adjusting the voltage acting on the piezoelectric plate to adjust the force applied to the film so as to change the volume of the acoustic cavity of the acoustic liner; wherein the voltage regulating mechanism comprises a variable resistance structure, two electrode conductors and a power supply; the variable resistance structure is arranged on the inner wall of the mounting hole; the two electrode conductors are arranged on the rotating shaft at intervals and are in electric contact with the variable resistance structure; the two electrode conductors are electrically connected to the two ends of the piezoelectric plate respectively; the power supply and the variable resistance structure form an electric loop. According to the open type rotor engine, under different working conditions, the volume of the acoustic lining acoustic cavity is controlled through the piezoelectric plate, and the targeted noise reduction requirement of an aero-engine under the complex working condition is met.

Description

Technical Field

[0001] The invention relates to the field of aviation engines, and in particular to an open rotor engine. Background Art

[0002] Aircraft engines are the largest source of carbon emissions in the aviation industry, and the next generation of low-carbon open rotor aircraft engine products is about to be launched. Low noise characteristics are the entry threshold for engine products to enter commercial operations.

[0003] Laying down acoustic lining is the most common means of reducing noise. The acoustic lining is composed of a perforated plate, a honeycomb structure and a solid wall at the back. Its working principle is that sound waves excite pressure fluctuations at the mouth of the resonance cavity during propagation, which in turn causes fluctuations in the resonance cavity and dissipates the energy of the sound waves. It can be regarded as a combination of many Helmholtz resonators, and the structural characteristics of the resonance cavity determine the sound absorption frequency.

[0004] The unducted design of the open rotor engine makes the noise problem particularly prominent. The noise can only be reduced by laying acoustic liners on the surface of the stator blades. Since the area of ​​acoustic liners that can be arranged is small, how to make the most of the acoustic liners has become the research focus of noise reduction design.

[0005] The traditional sound lining structure can only meet the noise reduction requirements of a fixed frequency band. The closed cavity volume, neck height and neck cross-sectional area of ​​the traditional sound-absorbing board's Helmholtz silencer cannot be changed after the design is completed. Therefore, its sound absorption frequency is unique and can only achieve a noise reduction effect for a narrow frequency band. The noise reduction effect at other frequencies is almost zero.

[0006] In recent years, designs such as multi-degree-of-freedom acoustic lining and super-structure acoustic lining have emerged, but they only increase the length of the fixed frequency band and cannot meet the noise reduction needs of multiple working conditions. However, aircraft engines have many working conditions during operation, and the noise reduction needs cannot be confined to a single frequency band. Therefore, designing a stator blade acoustic lining for open rotor engines has become an important requirement for noise reduction of open rotor engines. Summary of the invention

[0007] Based on this, the present application provides an open rotor engine to solve or at least improve the problems mentioned in the above background technology.

[0008] The present application provides an open rotor engine, comprising: rotor blades; stator blades arranged upstream or downstream of the rotor blades, the stator blades comprising a rotating shaft; a hub, a mounting hole being provided on the hub, the rotating shaft of the stator blades being arranged in the mounting hole; a variable pitch mechanism, the variable pitch mechanism being used to actuate the rotating shaft to change the pitch angle of the stator blades; an adjustable acoustic liner, the adjustable acoustic liner being arranged on the surface of the stator blades; the adjustable acoustic liner comprising a film, a perforated plate and a piezoelectric sheet, the film and the perforated plate forming a sound cavity, the piezoelectric sheet It is arranged on the film; a voltage regulating mechanism, which is used to adjust the voltage acting on the piezoelectric sheet to adjust the force applied to the film to change the volume of the sound cavity; wherein the voltage regulating mechanism includes a variable resistor structure, two electrode conductors and a power supply; the variable resistor structure is arranged on the inner wall of the mounting hole; the two electrode conductors are arranged at intervals on the rotating shaft and are electrically contacted with the variable resistor structure; and the two electrode conductors are electrically connected to the two ends of the piezoelectric sheet respectively; the power supply and the variable resistor structure form an electrical circuit.

[0009] Furthermore, the variable resistor structure includes a first resistor arc segment and a second resistor arc segment that are electrically connected; wherein the resistivity of the first resistor arc segment is different from that of the second resistor arc segment.

[0010] Furthermore, the first resistor arc segment is a semicircular ring; the second resistor arc segment has two, and is symmetrically arranged at both ends of the first resistor arc segment; one end of each of the second resistor arc segments is electrically connected to the first resistor arc segment, and the other end of each of the second resistor arc segments is connected to the positive or negative pole of the power supply.

[0011] Furthermore, the two electrode conductors are arranged on the rotation axis at an interval of 180°.

[0012] Furthermore, the adjustable acoustic liner includes a plurality of acoustic cavities and a plurality of piezoelectric sheets, each of the acoustic cavities corresponds one to one with each of the piezoelectric sheets; and the piezoelectric sheets are connected in parallel.

[0013] Furthermore, the film is spaced apart from the surface of the stator blade, and the piezoelectric sheet is arranged on a side of the film close to the surface of the stator blade.

[0014] Furthermore, the adjustable acoustic liner is arranged on the pressure surface and / or suction surface of the stator blade.

[0015] Furthermore, on the pressure surface side of the stator blade, the area of ​​the adjustable acoustic liner accounts for 60% to 90% of the surface area of ​​the pressure surface; and / or, on the suction surface side of the stator blade, the area of ​​the adjustable acoustic liner accounts for 60% to 90% of the surface area of ​​the suction surface.

[0016] The present application adjusts the voltage on the piezoelectric sheet to change the volume of the acoustic cavity in the adjustable acoustic liner, thereby changing the frequency of the absorbed noise. The frequency of noise generated by the engine under different working conditions is often different. Therefore, the present application can adaptively adjust the size of the acoustic cavity according to the different working conditions of the engine to adapt to the frequency of noise under different working conditions, thereby improving the noise reduction effect and meeting the noise reduction requirements of multiple working conditions.

[0017] More specifically, the present application couples the engine operating conditions-stator blade pitch angle-voltage on the piezoelectric film-deformation of the film-sound absorption frequency, thereby achieving targeted noise reduction requirements for different operating conditions. The entire design is only combined with the variable pitch mechanism necessary for the operation of the open rotor engine, and there is no need to add a new control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 It is a schematic structural diagram of an open rotor engine according to an embodiment of the present invention.

[0020] Figure 2 It is a schematic diagram of the assembly of the stator blades and the hub of an open rotor engine according to an embodiment of the present invention.

[0021] Figure 3 It is a structural cross-sectional view of an adjustable acoustic liner according to an embodiment of the present invention.

[0022] Figure 4 It is a schematic diagram of the electrical connection between the piezoelectric sheet and the electrode conductor on the stator blade according to an embodiment of the present invention.

[0023] Figure 5 Schematic diagram of a voltage regulation mechanism according to an embodiment of the present invention.

[0024] Figure 6 It is an equivalent circuit diagram of voltage regulation on a piezoelectric chip according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0026] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0027] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0028] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0029] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0030] The terms "upstream" and "downstream" refer to relative directions relative to the flow of a fluid in a fluid path. For example, "upstream" refers to the direction from which the fluid is flowing, and "downstream" refers to the direction toward which the fluid is flowing.

[0031] The term "open rotor engine" refers to a gas turbine engine that generates thrust by driving a propeller fan through the output shaft power of a power turbine. It is a new type of engine between turboprops and turbofans, also known as a propfan engine or an unducted fan engine. It is mainly composed of four major components: a gas generator, a power turbine, a transmission device, and a propfan. According to the different positions of the propfan in the engine, it can be divided into traction type and propulsion type; according to the drive mode, it can be divided into gear drive and direct drive. Open rotor engines have high propulsion efficiency under high subsonic cruise conditions and are an important development direction for commercial aviation engines.

[0032] See also Figure 1 , an open rotor engine is provided, comprising a rotor blade 1 and a stator blade 2 arranged downstream of the rotor blade 1.

[0033] Exemplarily, the rotor blade 1 is mounted on the rotor disk 3. The rotor blade 1 may be provided in plurality and spaced apart from each other in the circumferential direction, and may extend outwardly in a generally radial direction. For example, the rotor blade 1 is a fan blade, and a plurality of fan blades may be mounted on the fan disk in a circumferentially spaced manner. The rotor blade 1 may rotate under the drive of a power turbine to provide traction or propulsion to an aircraft.

[0034] The stator blades 2 located downstream of the rotor blades 1 guide the outlet airflow of the rotor blades 1, reduce the turbulence and vortex generated by the rotor blades 1, and guide the airflow to flow along a predetermined path, thereby achieving control of the airflow direction, thereby improving the aerodynamic efficiency of the engine. The stator blades 2 do not participate in the rotation, so the stator blades 2 are mounted on the stationary frame or other mounting structure of the engine. For example, the stator blades 2 are mounted on the hub 4. A plurality of stator blades 2 may be circumferentially spaced from each other and may extend outward generally in the radial direction.

[0035] Of course, it is understandable that the stator blades may also be arranged upstream of the rotor blades to guide the inlet airflow of the rotor blades. For example, in some embodiments, stator blades are arranged upstream and downstream of the rotor blades without departing from the essence of the present application.

[0036] The stator blades 2 can be arranged to be completely fixed, or can be deflected around their own axis. Figure 2 The stator blades 2 are configured as adjustable stator blades. In other words, the stator blades 2 can be deflected around their own axis A to change the pitch angle of the stator blades 2 .

[0037] Adjustment of the pitch angle of the stator blades 2 can be selectively performed in various flight conditions to change the thrust or airflow effect. For example, the magnitude and / or direction of the thrust generated by the rotor blades 1 can be adjusted by changing the pitch angle of the stator blades 2.

[0038] The adjustment of the pitch angle of the stator blades 2 can be achieved through a variable pitch mechanism. The variable pitch mechanism can change the pitch angle of one or more stator blades 2. In other words, the pitch angle of the corresponding stator blades among the multiple stator blades 2 can be changed individually or synchronously by the variable pitch mechanism. It can be understood that the variable pitch mechanism belongs to the prior art and will not be described in detail here. Exemplarily, the variable pitch mechanism is arranged in the hub 4. Under different flight conditions, the pitch angle of the stator blades 2 of the open rotor engine can be changed, that is, the variable pitch mechanism in the hub 4 controls the stator blades 2 to deflect.

[0039] In a specific embodiment, see Figure 2 The hub 4 is provided with a mounting hole 41, and the stator blade 2 includes a rotating shaft 21 at the blade root, and the rotating shaft 21 is arranged in the mounting hole 41. Exemplarily, the rotating shaft 21 has a cylindrical surface, so it can rotate in the mounting hole 41 of the hub 4 under the actuation of the pitch mechanism, thereby changing the pitch angle of the stator blade.

[0040] For different engine operating conditions, such as changes in engine thrust or asymmetric aerodynamic loads, the pitch angle of the stator blades 2 can be at least partially changed to adapt to the above different operating conditions. Under different engine operating conditions, the noise frequency generated by the engine is complex and changeable. The traditional acoustic liner that absorbs fixed frequency band noise can no longer meet the noise reduction requirements of open rotor engines under different operating conditions.

[0041] The acoustic liner is equivalent to a Helmholtz resonator, which can be simplified as a spring damping system. The air in the neck can be regarded as a mass block, and the air in the cavity can be regarded as a spring. Its sound absorption frequency can be expressed by the formula: , where V0 is the cavity volume, S0 is the neck cross-sectional area, and L0 is the neck height. c It is the speed of sound. It can be seen that by adjusting the cavity volume, the sound absorption frequency of the sound lining can be effectively adjusted.

[0042] Therefore, continue to see Figure 1 The open rotor engine also includes an adjustable acoustic liner 5, which is arranged on the surface of the stator blade 2, for example, fixed to the pressure surface and / or suction surface of the stator blade 2. In a specific embodiment, in order to improve the noise reduction effect of the adjustable acoustic liner 5, it is arranged on the pressure surface and suction surface of the stator blade 2. Further, on the pressure surface side of the stator blade 2, the area of ​​the adjustable acoustic liner 5 accounts for 60% to 90% of the surface area of ​​the pressure surface of the stator blade 2; on the suction surface side of the stator blade 2, the area of ​​the adjustable acoustic liner 5 accounts for 60% to 90% of the surface area of ​​the suction surface of the stator blade 2. In this way, the noise reduction effect is further improved while taking into account the aerodynamic shape and performance of the stator blade 2.

[0043] See also Figure 3In a specific embodiment, the adjustable acoustic liner 5 includes a film 51, a perforated plate 52 and a piezoelectric sheet 53. The film 51 and the perforated plate 52 constitute an acoustic cavity 54. During the propagation of sound waves, pressure fluctuations at the mouth of the acoustic cavity 54 are excited, which in turn causes fluctuations in the acoustic cavity 54, thereby dissipating the energy of the sound waves. Among them, the piezoelectric sheet 53 is arranged on the film 51, and the piezoelectric sheet 53 is configured to be able to apply different forces to the film 51 according to the different voltages acting on the piezoelectric sheet 53, so as to change the volume of the acoustic cavity 54. A piezoelectric sheet is a device that will produce mechanical deformation as the voltage changes when it is acted upon; illustratively, the piezoelectric sheet is a piezoelectric ceramic sheet.

[0044] Continue to see Figure 3 The film 51 is spaced from the surface of the stator blade 2, and the piezoelectric sheet 53 is disposed on the side of the film 51 close to the surface of the stator blade 2. It should be noted that the distance between the piezoelectric sheet 53 and the surface of the stator blade 2 can meet the deformation requirement of the film 51.

[0045] Therefore, when different voltages are applied to the piezoelectric sheet 53, the piezoelectric sheet 53 is mechanically deformed and different stresses are applied to the film 51, thereby changing the volume of the sound cavity 54 and further changing the frequency of the absorbed noise. In addition, the open rotor engine also includes a voltage regulating mechanism, which is used to adjust the voltage applied to the piezoelectric sheet 53.

[0046] In this embodiment, the adjustable acoustic liner 5 includes a series of acoustic cavities 54 and piezoelectric sheets 53 . The acoustic cavities 54 correspond to the piezoelectric sheets 53 one by one, and the plurality of piezoelectric sheets 53 are connected in parallel.

[0047] In this way, by adjusting the voltage on the piezoelectric sheet, the volume of the sound cavity in the adjustable sound liner can be changed, thereby changing the frequency of the absorbed noise. The frequency of noise generated by the engine under different working conditions is often different. Therefore, the present application can adaptively adjust the size of the sound cavity according to the different working conditions of the engine to adapt to the frequency of noise under different working conditions, thereby improving the noise reduction effect and meeting the noise reduction requirements of multiple working conditions.

[0048] It is understandable that the voltage regulating mechanism can be set to achieve the regulation of the voltage on the piezoelectric sheet, and the specific implementation form is not limited in this application. For example, the regulation of the voltage on the piezoelectric sheet can be achieved through the engine control system and the control circuit. The engine control system can be based on the specific engine working conditions. The engine requires different thrusts in different operating conditions. For an open fan engine, the method of changing the thrust is to adjust the blade pitch angle and the speed. Taking the airworthiness noise measurement working condition as an example, the three working conditions of the sideline, flyover, and approach have different speed and thrust requirements. The voltage on the piezoelectric sheet can be adjusted to change the sound absorption frequency of the acoustic lining to adapt to different engine working conditions.

[0049] See also Figure 4 and Figure 5 In this embodiment, the voltage regulating mechanism 6 is coupled with the pitch angle adjustment of the stator blade 2, thereby achieving a more convenient adjustment. Specifically, the voltage regulating mechanism 6 includes a variable resistor structure 61, two electrode conductors 62 and a power supply 63.

[0050] The variable resistor structure 61 is arranged on the inner wall of the mounting hole 41 of the hub 4; two electrode conductors 62 are arranged on the rotating shaft 21 of the stator blade 2 at intervals and are in electrical contact with the variable resistor structure 61; and the two electrode conductors 62 are electrically connected to the two ends of the piezoelectric sheet 53 respectively; the power supply 63 forms an electrical circuit with the variable resistor structure 61. The power supply 63 can be selected as a power supply for providing power to the motor of the pitch mechanism, and no further limitation is made here.

[0051] Therefore, when the pitch angle of the stator blade 2 changes, the two electrode conductors 62 on the rotating shaft 21 of the stator blade 2 slide in electrical contact on the variable resistor structure 61, changing the resistance value in parallel with the piezoelectric piece 53 in the circuit, and then changing the voltage across the piezoelectric piece 53, thereby achieving that when the pitch angle of the stator blade changes under different working conditions, the resistance value in parallel with the piezoelectric piece changes synchronously, and then changes the voltage on the piezoelectric piece, thereby specifically controlling the film deformation amount, and then changing the size of the acoustic cavity of the Helmholtz resonator, thereby controlling the sound absorption frequency.

[0052] In this embodiment, the two electrode conductors 62 are arranged 180° apart on the rotating shaft 21. As for the variable resistor structure 61, in order to facilitate the two electrode conductors 62 to electrically contact and slide with the stator blade 2 during the rotation process, the variable resistor structure 61 is arranged in an arc or annular shape and fits the inner wall of the mounting hole 41.

[0053] Continue to see Figure 5 The variable resistor structure 61 includes a first resistor arc segment 611 and a second resistor arc segment 612 which are electrically connected, wherein the first resistor arc segment 611 and the second resistor arc segment 612 have different resistivities, for example, the first resistor arc segment 611 has a greater or smaller resistivity than the second resistor arc segment 612. Exemplarily, the first resistor arc segment 611 is a semicircular ring, and the second resistor arc segment 612 has two and is symmetrically arranged at both ends of the first resistor arc segment 611; one end of each second resistor arc segment 612 is electrically connected to the first resistor arc segment 611, and the other end of each second resistor arc segment 612 is connected to the positive electrode or the negative electrode of the power supply 63.

[0054] In addition, in order to make the variable resistor structure 61 form a whole ring, the variable resistor structure 61 may further include a third resistor arc segment 613, and the third resistor arc segment 613 is arranged between the two second resistor arc segments 612. In other words, the variable resistor structure 61 constituting the whole ring is the first resistor arc segment 611, the second resistor arc segment 612, the third resistor arc segment 613 and the second resistor arc segment 612 connected end to end in sequence.

[0055] Optionally, the third resistor arc segment 613 has a different resistivity from the first resistor arc segment 611 and the second resistor arc segment 612, for example, the third resistor arc segment 613 has a greater resistivity. In some specific embodiments, the third resistor arc segment 613 may be made of a non-conductive material, for example, the material of the third resistor arc segment 613 is rubber.

[0056] See also Figure 6 , is an equivalent circuit diagram for adjusting the voltage on the piezoelectric sheet. When the pitch angle of the stator blade 2 changes, it is equivalent to adjusting the sliding resistor in the equivalent circuit diagram, that is, changing the voltage across the piezoelectric sheet 53.

[0057] It can be understood that due to the adjustment of the stator blades 2 to the positive pitch angle and the negative pitch angle, that is, the clockwise deflection or counterclockwise deflection of the stator blades, they can be considered as two symmetrical and equivalent working conditions, and the noise frequency and noise level generated are equivalent. Therefore, the symmetrical setting of the above-mentioned variable resistor structure 61 and the symmetrical setting of the two electrode conductors 62 can make the voltage acting on the two ends of the piezoelectric sheet the same when the stator blades are deflected clockwise or counterclockwise at the same pitch angle, so the frequency of the noise that can be absorbed is also equivalent, thereby simplifying the design while being able to meet different engine operating conditions.

[0058] Of course, it can be understood that the arrangement and distribution of the resistance arc segments in the variable resistor structure 61 is not limited to the method in the above-mentioned embodiment. It can change the voltage across the piezoelectric film accordingly according to the change of the pitch angle of the stator blades in response to different operating conditions of the engine. For example, each pitch angle can be formed into a one-to-one correspondence with the voltage acting on the piezoelectric film, and the distribution of resistance values ​​in the variable resistor structure can be optimized thereby, which does not deviate from the essence of the present application.

[0059] In a specific embodiment, for example, when an open rotor engine changes from a take-off condition to a flyby condition, the thrust required by the engine decreases, while the main noise frequency of the engine changes from 500 Hz to 1000 Hz, and the frequency band requiring noise reduction increases; at the same time, in order to meet the demand for reduced thrust, the pitch angle of the stator blades is reduced, the voltage across the piezoelectric film is reduced, and the deformation of the film is reduced, thereby reducing the volume of the cavity in the acoustic liner and increasing the corresponding noise reduction frequency of the acoustic liner, thereby improving the noise reduction effect under different working conditions.

[0060] In summary, in this embodiment, the working condition of the open rotor engine changes, and the pitch angle of the stator blades changes accordingly, so that the voltage acting on the piezoelectric sheet changes, and the piezoelectric sheet drives the film to deform, so that the volume of the acoustic cavity of the Helmholtz resonator changes, and the sound absorption frequency changes, and finally adapts to the change in noise frequency caused by the change in the engine working condition. That is, the engine working condition-stator blade pitch angle-voltage on the piezoelectric sheet-film deformation-sound absorption frequency are coupled, and the targeted noise reduction requirements for different working conditions are realized, and the entire design is only combined with the necessary variable pitch mechanism when the open rotor engine is working, without adding a new control system.

[0061] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0062] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. An open rotor engine, characterized in that: include: Rotor blades; A stator blade disposed upstream or downstream of the rotor blade, the stator blade comprising a rotating shaft; A hub, wherein a mounting hole is formed on the hub, and a rotating shaft of the stator blade is arranged in the mounting hole; A pitch-changing mechanism, the pitch-changing mechanism being used to actuate the rotating shaft to change the pitch angle of the stator blades; An adjustable acoustic liner, the adjustable acoustic liner is arranged on the surface of the stator blade; the adjustable acoustic liner comprises a film, a perforated plate and a piezoelectric sheet, the film and the perforated plate constitute an acoustic cavity, and the piezoelectric sheet is arranged on the film; A voltage regulating mechanism, the voltage regulating mechanism is used to adjust the voltage acting on the piezoelectric sheet to adjust the force applied to the film to change the volume of the acoustic cavity; Wherein, the voltage regulating mechanism comprises a variable resistor structure, two electrode conductors and a power supply; The variable resistor structure is arranged on the inner wall of the mounting hole; The two electrode conductors are arranged on the rotating shaft at intervals and are in electrical contact with the variable resistor structure; and the two electrode conductors are electrically connected to two ends of the piezoelectric sheet respectively; The power source and the variable resistor structure form an electric loop.

2. The open rotor engine according to claim 1, characterized in that: The variable resistor structure includes a first resistor arc segment and a second resistor arc segment that are electrically connected; The resistivity of the first resistance arc segment is different from that of the second resistance arc segment.

3. The open rotor engine according to claim 2, characterized in that: The first resistance arc segment is a semicircular ring; The second resistor arc segments have two segments, which are symmetrically arranged at two ends of the first resistor arc segment; One end of each of the second resistance arc segments is electrically connected to the first resistance arc segment, and the other end of each of the second resistance arc segments is connected to the positive electrode or the negative electrode of the power supply.

4. The open rotor engine according to claim 3, characterized in that: The two electrode conductors are arranged on the rotation axis at an interval of 180°.

5. The open rotor engine according to claim 1, characterized in that: The adjustable acoustic liner includes a plurality of acoustic cavities and a plurality of piezoelectric sheets, each of the acoustic cavities corresponds to each of the piezoelectric sheets one by one; and the piezoelectric sheets are connected in parallel.

6. The open rotor engine according to claim 1, characterized in that: The film is spaced apart from the surface of the stator blade, and the piezoelectric sheet is arranged on a side of the film close to the surface of the stator blade.

7. The open rotor engine according to claim 1, characterized in that: The adjustable acoustic liner is arranged on the pressure surface and / or the suction surface of the stator blade.

8. The open rotor engine according to claim 7, characterized in that: On the pressure surface side of the stator blade, the area of ​​the adjustable acoustic liner accounts for 60% to 90% of the surface area of ​​the pressure surface; And / or, on the suction surface side of the stator blade, the area of ​​the adjustable acoustic liner accounts for 60% to 90% of the surface area of ​​the suction surface.

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