Open type fan component of open type rotor engine, open type rotor engine and noise reduction method

Abstract

The invention relates to an open type fan component of an open type rotor engine, the open type rotor engine and a noise reduction method. The open-type fan component comprises a stator, a plurality of fan blades and a plurality of fan blades, the rotor comprises rotor blades which are connected to a rotating shaft, and the rotor blades rotate along with the rotation of the rotating shaft; wherein the stator blade is located at the upstream of the rotor blade; the base is connected with the stator fixing force bearing device through the hydraulic executing mechanism. The open type fan component has a first state and a second state, wherein in the first state, the radial position where the radial outer end of the stator blade is located is the first position; and in the second state, the radial position where the radial outer end of the stator blade is located is a second position, and the second position is located on the radial inner side relative to the first position. By the adoption of the fan component, the advantage of low oil consumption of the engine is reserved, and the problem that BPF noise of the engine near an airport is too large is solved.

Description

Technical Field

[0001] This application relates to an open fan component of an open rotor engine, an open rotor engine, and a noise reduction method. Background Art

[0002] An open rotor engine, also known as an open fan engine, combines the characteristics of a turboprop engine with a low fuel consumption rate and a turbofan engine with a high flight speed. Compared with a turbofan engine of the same technical level, an open fan engine has technical advantages such as high propulsion efficiency, low fuel consumption, and high cycle efficiency. However, at the same time, it also has technical difficulties such as difficult integration of the engine and the aircraft, excessive noise, and poor reliability. The biggest challenge is the noise problem. For a ducted open rotor engine, the noise generated by the propeller fan cannot be reduced by the nacelle acoustic lining as in a traditional turbofan engine, and can only be improved through aerodynamic acoustic design, which highlights the importance of aerodynamic acoustic design technology in the design of the propeller fan. The biggest noise source comes from the open fan component. The noise spectrum diagram of a typical open fan component is as follows Figure 2 shown, consisting of tonal noise and broadband noise. It includes the 1st and 2nd blade passing frequencies (BPF), broadband noise, and the vibration shaft frequency tone.

[0003] The primary goal of solving the noise problem is to meet the limitations of airworthiness noise regulations. The regulations specifically target three aircraft flight conditions: approach, overflight, and sideline. That is, during the takeoff and landing phases of the aircraft at the airport, the regulations have clear limitations on the noise radiation energy received by the microphone measurement points corresponding to these three conditions. The specific noise measurement points are shown in Figure 1 , and the approach measurement point A, the sideline measurement point S, and the overflight measurement point F are illustrated. In addition, since the human ear is more sensitive to high-energy tonal noise, the airworthiness regulations perform a tonal correction penalty on the BPF tones shown in Figure 2 , highlighting the disturbing effect of tonal noise on the human ear. Whether the BPF noise of the engine can be controlled is the key for the engine to meet the airworthiness regulations.

[0004] The structural design of an open fan engine in a comparative solution is as follows Figure 3As shown, the open fan component includes a rotor and a stator. The stator may include stator blades 1, a stator fixed load-bearing device 6, and a base 7. The stator blades 1 are supported by the base 7, and the base 7 is disposed on the stator fixed connection device 5 and is disposed on the stator fixed load-bearing device 6 through the stator fixed connection device 5. The rotor may include rotor blades 2 and a rotating shaft 3. The rotating shaft 3 is supported by a ball bearing 4. The main function of the rotor blades 2 located upstream is to accelerate air and generate thrust. By rotating at high speed, the rotor blades can transfer energy to the air flow, causing it to accelerate and flow backward, thereby generating forward thrust. The stator blades 1 are relatively fixed blades located downstream, and their main function is to rectify and guide the air flow. The air flow accelerated by the rotor blades 2 usually has a certain rotational component. The stator blades 2 can reduce this rotational motion and rectify the air flow into a more stable direct current, which helps to reduce eddy currents and energy losses and improve aerodynamic efficiency. The inventor found that Figure 2 the BPF noise shown in [reference] is mainly composed of two parts: the single tone generated by the individual rotor blades and the single tone generated by the interference between the tip vortices of the rotor and stator blades and the viscous wake. The inventor found that Figure 3 in the comparative scheme shown in [reference], it is difficult to meet the relevant requirements of airworthiness regulations for noise.

[0005] Therefore, there is a need in the art for a new open fan component of an open rotor engine, an open rotor engine, and a noise reduction method, so that the open rotor engine can freely switch between two states: "maximizing aerodynamic efficiency" and "sacrificing part of the aerodynamic efficiency to minimize BPF noise". This not only retains the technical advantages of the open fan engine such as low fuel consumption and high propulsion efficiency, but also solves the problem of excessive BPF noise radiated by the engine near the airport. Summary of the Invention

[0006] An object of the present application is to provide an open fan component of an open rotor engine.

[0007] An object of the present application is to provide a noise reduction method.

[0008] An object of the present application is to provide an open rotor engine.

[0009] An open fan component of an open rotor engine according to a first aspect of the present application includes: a stator including stator blades and a base; a rotor including rotor blades connected to a rotating shaft, and the rotor blades rotate with the rotation of the rotating shaft; wherein, the stator blades are located downstream of the rotor blades; and the radial dimension of the stator blades is variable; the open fan component has a first state and a second state: the radial dimension of the stator blades is smaller than that of the rotor blades; in the first state, the radial outer end of the stator blades is located at a first position such that the radial dimension of the stator blades is a first radial dimension; in the second state, the radial outer end of the stator blades is located at a second position such that the radial dimension of the stator blades is a second radial dimension, and the second position is radially inward relative to the first position, and the second radial dimension is smaller than the first radial dimension; the open fan component can reciprocally move the stator blades from the first position to the second position through the actuator to switch between the first state and the second state; in the first position, the open fan component reaches a predetermined optimal aerodynamic efficiency; in the second position, the open fan component reaches a predetermined optimal noise reduction efficiency.

[0010] In one or more embodiments of the open fan component, the radial dimension of the rotor blades is D. In the first state, the radial outer end of the stator blades is located at the first position such that the radial dimension of the stator blades is 0.88D to 0.92D. In the second state, the radial outer end of the stator blades is located at the second position such that the radial dimension of the stator blades is 0.73D to 0.77D.

[0011] In one or more embodiments of the open fan component, the radial dimension of the rotor blades is D. In the first state, the radial outer end of the stator blades is located at the first position such that the radial dimension of the stator blades is 0.90D. In the second state, the radial outer end of the stator blades is located at the second position such that the radial dimension of the stator blades is 0.75D.

[0012] In one or more embodiments of the open fan component, the actuator is a hydraulic actuator. The base is connected to a stator fixed bearing device through the hydraulic actuator. The hydraulic actuator includes an electro-hydraulic servo valve, an actuator, and a telescopic rod. The electro-hydraulic servo valve is electrically connected to an active noise controller, and controls the flow of the internal oil of the actuator by receiving the electrical signal of the active noise controller, thereby adjusting the actuator, so that the actuator changes the length of the telescopic rod to drive the stator blades to reciprocally move from the first position to the second position to switch between the first state and the second state.

[0013] In one or more embodiments of the open fan component, the actuator can drive the telescopic rod, and the actuator is provided with a displacement sensor, which is electrically connected to the active noise controller and can feedback the length parameter of the telescopic rod to the active noise controller in real time.

[0014] In one or more embodiments of the open fan component, the stator fixed bearing device provides a reserved space, and the reserved space provides a space for the hydraulic actuator to swing up and down on the stator fixed bearing device.

[0015] According to a noise reduction method of the second aspect of the present application, the open fan component described in the first aspect is used to reduce the noise of the open rotor engine.

[0016] In one or more embodiments of the noise reduction method, the noise reduction method includes the following steps: S100. Obtain the expected value Ref_L of the length parameter of the telescopic rod of the hydraulic actuator corresponding to different flight conditions; S200. The displacement sensor in the actuator of the hydraulic actuator feedbacks the real-time length parameter Ins_L of the telescopic rod to the active noise controller; the active noise controller performs real-time electrical signal control on the hydraulic servo valve according to the difference between Ref_L and Ins_L, so that Ins_L approaches Ref_L until the two are the same.

[0017] In one or more embodiments of the noise reduction method, the step of S100 includes: S101. Set the first radial dimension of the stator vane as the upper limit and the second radial dimension of the stator vane as the lower limit, and establish a function between the formed radial dimension interval and the flight condition; S102. Configure the function in the active noise controller.

[0018] In one or more embodiments of the noise reduction method, the step of S200 includes: performing real-time electrical signal control on the hydraulic servo valve, and the hydraulic servo valve and the actuator are set to have oil flowing through before, so that different electrical signals will have different control effects on the oil, so that Ins_L approaches Ref_L until the two are the same.

[0019] According to an open rotor engine of the third aspect of the present application, it includes the open fan component described in the first aspect.

[0020] The beneficial effects of this case include but are not limited to: Through the open fan component that can automatically control the extension length of the rear stator vanes, the engine can freely switch between two states of "maximizing aerodynamic efficiency" and "sacrificing part of the aerodynamic efficiency to minimize the fundamental frequency tonal noise", so as to achieve when the aircraft passes Figure 1When at the three measuring points shown and their vicinity, the open rotor with the radial dimension of variable stator vanes can automatically minimize its radiated tonal noise to the greatest extent. Specifically, when the engine is in the takeoff and landing state near the airport, the radiation noise problem needs to be considered as a priority. On the basis of ensuring that the aerodynamic performance of the engine basically meets the standards, for example, the stator vanes can be lowered by a hydraulic actuator to minimize the tonal noise generated by the interference between the rotor-stator tip vortices and the viscous wake to the greatest extent. When the engine is in a state far from the airport, the noise problem becomes a secondary issue, and the propulsion efficiency needs to be considered as a priority. For example, the stator vanes can be pulled back to an appropriate height by a hydraulic actuator to ensure the aerodynamic efficiency of the entire flight. Brief Description of the Drawings

[0021] The above and other features, properties, and advantages of the present application will become more apparent through the following description in conjunction with the drawings and embodiments. It should be noted that the drawings are only examples and are not drawn under the condition of equal scale, and should not be used to limit the actual protection scope required by the present application. Among them: Figure 1 It is a schematic diagram of the airworthiness noise measuring points near the airport.

[0022] Figure 2 It is a noise spectrum diagram of a typical open fan component.

[0023] Figure 3 It is a schematic structural diagram of an open rotor engine of a comparative scheme.

[0024] Figure 4 It is a schematic diagram of the first state of the open fan component of the open rotor engine according to an embodiment.

[0025] Figure 5 It is a schematic diagram of the second state of the open fan component of the open rotor engine according to an embodiment.

[0026] Figure 6 It is a schematic diagram of the hydraulic actuator of the open fan component of the open rotor engine according to an embodiment.

[0027] Figure 7 It is a schematic flowchart of a noise reduction method according to an embodiment.

[0028] Figure 8 It is a schematic diagram of the closed-loop control strategy of the hydraulic actuator of the open fan component of the open rotor engine according to an embodiment. [[ID=3८]]

[0029] Figure 9 It is a schematic flowchart of a noise reduction method according to another embodiment.

[0030] Reference Signs: 1 - Stator Vane 101 - First radial dimension 102 - Second radial dimension 2 - Rotor blade 3 - Rotating shaft 4 - Ball bearing 5 - Stator fixed connection device 6 - Stator fixed load-bearing device 61 - Reserved space 7 - Base 8 - Actuator 8a - Electro-hydraulic servo valve 8b - Actuator 8c - Telescopic rod 9 - Data cable. Detailed implementation manners

[0031] The following discloses various different implementation manners or embodiments for implementing the described subject technical solutions. To simplify the disclosure content, specific examples of each element and arrangement are described below. Of course, these are only examples and do not limit the protection scope of this application.

[0032] In addition, it should be understood that terms such as "one embodiment", "an embodiment", and / or "some embodiments", "one or more embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "some embodiments" or "one or more embodiments" mentioned twice or more at different positions in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined.

[0033] In the following description, the meanings of some terms are as follows.

[0034] Open rotor engine: That is, an open fan engine, also known as a ducted fan engine, is a new type of aircraft engine configuration designed to improve fuel efficiency and reduce pollutant emissions. The biggest difference from the traditional configuration turbofan engine is that the open rotor engine has no nacelle structure in the traditional sense, and the blades are exposed and generally longer and thinner. The open fan component mentioned in this application specifically refers to the combination of the rotor blade row and the stator blade row of this engine. The open rotor engine provided in this application includes the open fan component that will be introduced in detail in the following embodiments.

[0035] Stator: It refers to the fixed blades downstream of the rotor blades, and its main function is to guide and regulate the airflow to improve the efficiency and performance of the engine.

[0036] Blade Passing Frequency: The noise at the frequency points corresponding to the rotational speed and the number of blades generated due to the high-speed rotation of the rotor blades appears as regular discrete spikes in the noise spectrum. Its generation is the result of a combination of multiple factors, such as the rotational noise of the rotor itself, viscous wakes, and stator interference, and other complex aeroacoustic phenomena.

[0037] Approach: The flight state when the aircraft approaches the airport and prepares to land. The airworthiness noise regulations have clear microphone measurement point arrangements for the approach condition.

[0038] Takeoff: The flight state when the aircraft leaves the ground and accelerates at full power. The airworthiness noise regulations have clear microphone measurement point arrangements for the takeoff condition.

[0039] Overflight: The flight state when the aircraft is far from the airport and climbs upward. The airworthiness noise regulations have clear microphone measurement point arrangements for the overflight condition.

[0040] Hydraulic actuator: A mechanism that transmits and converts energy through the pressure of a liquid to achieve various mechanical movements and operations.

[0041] Electro-hydraulic servo valve: A device that uses an input electrical signal to control the flow of gas or liquid.

[0042] The three observation points of the general civil aircraft noise airworthiness regulations are as follows Figure 1 As shown, the design purpose of this application is that when the aircraft passes through these three measurement points and their vicinity, this open rotor with variable stator blade length can automatically minimize the tonal noise radiated by it to the greatest extent.

[0043] As Figure 4 And Figure 5 As shown, in some embodiments, the open fan component of the open rotor engine includes a stator and a rotor. The stator includes stator blade 1 and base 7; the rotor includes rotor blade 2 connected to rotating shaft 3, and rotor blade 2 rotates with the rotation of rotating shaft 3, and rotating shaft 3 can be supported by ball bearing 4. Stator blade 1 is located downstream of rotor blade 2, the radial dimension of stator blade 1 is smaller than the radial dimension of rotor blade 2, and the radial dimension of stator blade 1 is variable.

[0044] The open fan component has a first state as Figure 4 And Figure 5 The second state shown.

[0045] In the first state, the radial outer end of stator blade 1 is located at a first position, such that the radial dimension of stator blade 1 is the first radial dimension 101; In the second state, the radial position of the radial outer end of the stator blade 1 is the second radial position, so that the radial dimension of the stator blade is the second radial dimension 102. The second position is radially inner than the first position, and the second radial dimension 102 is smaller than the first radial dimension 101.

[0046] The open fan component can reciprocate the stator blades 1 from a first position to a second position to switch between the first state and the second state via the actuator 8. In the first position, the open fan component achieves a predetermined optimal aerodynamic efficiency, and in the second position, the open fan component achieves a predetermined optimal noise reduction efficiency.

[0047] and Figure 3 Compared with the comparative scheme shown in the figure, the structure of the open fan component with variable radial size of the stator blade 1 abandons the Figure 3 The stator fixing connection device 5 shown in the figure is connected and fixed by two actuators 8 in front and behind the stator base 7. The actuators 8 can correspond to different radial dimensions of the stator blades 1 in different elongation states to adapt to different flight states. Figure 4 As shown, in the first position, the open fan component achieves the predetermined optimal aerodynamic efficiency, ensuring the aerodynamic efficiency of the flight at a suitable altitude, but at the cost of the inevitable interference of the rotor and stator tip vortex and viscous wake single-tone noise, which is suitable for use in the cruise state. Figure 5 As shown, in the second position, the open fan component achieves the predetermined optimal noise reduction efficiency, and the stator blade 1 is pushed into the fuselage to eliminate the single-tone noise generated by the interference of the rotor-static wake and the tip vortex as much as possible, but at the cost of sacrificing some propulsion efficiency, which is suitable for use near the airport.

[0048] Specifically, in some embodiments, the inventors have discovered that the specific values of the first radial dimension 101 and the second radial dimension 102 can be as described below: defining the radial dimension of the rotor blade as D, in a first state, the radial outer end of the stator blade is located in a first position, such that the first radial dimension 101 of the stator blade is 0.88D to 0.92D; in a second state, the radial outer end of the stator blade is located in a second position, such that the second radial dimension 102 of the stator blade is 0.73D to 0.77D. In some embodiments, defining the radial dimension of the rotor blade as D, in a first state, the radial outer end of the stator blade is located in a first position, such that the first radial dimension 101 of the stator blade is 0.90D; in a second state, the radial outer end of the stator blade is located in a second position, such that the second radial dimension 102 of the stator blade is 0.75D.

[0049] The beneficial effect of this is that it can achieve both the aerodynamic efficiency and noise reduction effect of the engine.

[0050] The inventors found that for the downstream stator vanes, which can also be referred to as swirl recovery vanes (SRVs), the main function of the SRVs is to guide the airflow and improve the airflow stability. If the radial size of the SRVs is too large, firstly, the noise problem will be more prominent (airflow disturbance and pressure fluctuation), and secondly, it may cause additional aerodynamic drag, resulting in a decrease in efficiency. On the contrary, if the radial size is too small, it cannot play the role of improving the airflow stability, reducing energy loss, and thus increasing the propulsion efficiency. Therefore, it is difficult to find a suitable radial size for the SRVs to meet the requirements of aerodynamic efficiency and noise reduction.

[0051] Furthermore, through long-term research, the inventors found that as the radial size of the SRVs decreases from slightly below D (0.88D to 0.92D) to 0.73D to 0.77D, in the case of a low advance ratio, the aerodynamic efficiency will continuously decrease until it reaches about 20%, while in the case of a high advance ratio, the aerodynamic efficiency only slightly decreases, and the weakening trend is relatively slow. Among them, the advance ratio = incoming flow velocity / (blade rotation speed * blade disc diameter). And as the radial size of the SRVs decreases from slightly below D (0.88D to 0.92D) to 0.73D to 0.77D, at most frequencies of most far-field observation angles, the noise has a significant attenuation, and the total sound pressure level can reach a noise reduction of about 5 dB, and the noise reduction effect is remarkable. However, if the radial size of the SRVs is further reduced, for example, reduced to 0.65D, the noise reduction amount does not significantly decrease, but it will lead to a significant decrease in aerodynamic efficiency. The inventors found that within the adjustment range of the lower limit of 0.73D to 0.77D and the upper limit of 0.88D to 0.92D for the radial size of the SRVs, the balance between aerodynamic efficiency and noise reduction can be achieved, and it can be adjusted between the aforementioned lower limit and upper limit according to different scenarios and working conditions requirements, so as to simultaneously meet the aerodynamic efficiency and noise reduction performance of the engine.

[0052] As Figure 6 shown, the structure of the actuator 8 can be a hydraulic actuator, and the hydraulic actuator includes an electro-hydraulic servo valve 8a, an actuator 8b, and a telescopic rod 8c. The electro-hydraulic servo valve 8a can be connected to the active noise controller through a data line 9, but it is not limited thereto. For example, it can also be connected through wireless connection methods such as Bluetooth, 5G, and WiFi. By changing the electrical signal to control the flow of the internal hydraulic oil, and then adjusting the actuator 8b to change the length of the telescopic rod 8c, so as to drive the stator vane 1 to reciprocate from the first position to the second position to switch between the first state and the second state.

[0053] The actuator 8b can drive the telescopic rod 8c, and the actuator 8b is internally provided with a displacement sensor, which can feedback the real-time length parameter of the telescopic rod 8c to the active noise controller. The material selection of the telescopic rod 8c should preferably ensure its strength and service life to ensure that the stator vane is stable enough in various states.

[0054] Continue to refer to Figure 4 、 Figure 5 As shown, the base 7 is connected to the stator fixed bearing device 6 through a hydraulic actuator. The stator fixed bearing device 6 provides a reserved space 61, and the reserved space 61 provides a space for the hydraulic actuator to swing up and down on the stator fixed bearing device 6.

[0055] Refer to Figure 7 As shown, the present application also provides a noise reduction method, which uses the open fan component introduced in the above embodiments to reduce the noise of the open rotor engine.

[0056] As Figure 7 shown, in some embodiments, the noise reduction method may include the following steps: S100. Obtain the expected value Ref_L of the telescopic rod length parameter of the hydraulic actuator corresponding to different flight conditions.

[0057] S200. The displacement sensor in the actuator of the hydraulic actuator real-time feeds back the real-time length parameter Ins_L of the telescopic rod to the active noise controller; the active noise controller performs real-time electrical signal control on the hydraulic servo valve according to the difference between Ref_L and Ins_L, so that Ins_L approaches Ref_L until the two are the same.

[0058] Specifically, the real-time electrical signal control of the hydraulic servo valve by the active noise controller can be Figure 8 as shown in the closed-loop control, but not limited thereto.

[0059] As Figure 9 shown, the specific strategy of the closed-loop control may include: S101. Set the first radial dimension 101 of the stator vane as the upper limit and the second radial dimension 102 of the stator vane as the lower limit, and establish a function between the formed radial dimension interval and the flight conditions; S102. Configure the function in the active noise controller.

[0060] Specifically, the control strategy can be transformed from the airworthiness noise requirements. For example, according to a set of expected values Ref_L of the telescopic rod length parameters corresponding to the flight conditions (taking the ground clearance H as an example, but not limited thereto, other parameters can also be added for more precise control), the radial dimension interval formed by the first radial dimension 101 and the second radial dimension 102 corresponding to the stator vane 1 is established with the ground clearance H. The function expression can be obtained by measuring through the airworthiness flight test multiple times and then interpolating and fitting the discrete data. Finally, the offline function is configured in the active noise controller.

[0061] As Figure 8As shown, the closed-loop control strategy can be that the displacement sensor in the actuator 8b feeds back the real-time length parameter Ins_L of the telescopic rod 8c to the active noise controller. The controller performs real-time electrical signal control on the hydraulic servo valve 8a according to the difference between Ref_L and Ins_L. There is oil connection between the hydraulic servo valve 8a and the actuator 8b. Different electrical signals will produce different control effects on the oil, so that Ins_L gets closer and closer to Ref_L until they are the same.

[0062] It can be understood that the radial dimension of the stator vane 1 is automatically changed according to the real-time height H parameter from the ground. This radial dimension can also be actively taken over by the aircraft pilot according to actual needs for control, as well as other similar forms of active or automatic control of the stator vane 1 to balance the aerodynamic efficiency and noise radiation of the engine, and all are not limited thereto.

[0063] Although the present application is disclosed as above in the above embodiments, it is not used to limit the present application. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, all modifications, equivalent changes and decorations made to the above embodiments based on the technical essence of the present application without departing from the technical solution of the present application shall fall within the protection scope defined by the claims of the present application.

Claims

1. An open fan component of an open rotor engine, characterized in that, Comprising: A stator, including stator blades and a base; A rotor, including rotor blades connected to a rotating shaft, and the rotor blades rotate with the rotation of the rotating shaft; Wherein, the stator blades are located downstream of the rotor blades; and the radial dimension of the stator blades is variable; The open fan component has a first state and a second state: The radial dimension of the stator blades is smaller than that of the rotor blades; In the first state, the radially outer end of the stator blades is located at a first position in the radial direction, such that the radial dimension of the stator blades is a first radial dimension; In the second state, the radially outer end of the stator blades is located at a second position in the radial direction, such that the radial dimension of the stator blades is a second radial dimension, and the second position is radially inner relative to the first position, and the second radial dimension is smaller than the first radial dimension; The open fan component can reciprocally move the stator blades from the first position to the second position through an actuator to switch between the first state and the second state; In the first position, the open fan component achieves a predetermined optimal aerodynamic efficiency; In the second position, the open fan component achieves a predetermined optimal noise reduction efficiency.

2. The open fan component according to claim 1, characterized in that The radial dimension of the rotor blades is D. In the first state, the radially outer end of the stator blades is located at the first position such that the radial dimension of the stator blades is 0.88D to 0.92D. In the second state, the radially outer end of the stator blades is located at the second position such that the radial dimension of the stator blades is 0.73D to 0.77D.

3. The open fan component according to claim 2, wherein, The radial dimension of the rotor blades is D. In the first state, the radially outer end of the stator blades is located at the first position such that the radial dimension of the stator blades is 0.90D. In the second state, the radially outer end of the stator blades is located at the second position such that the radial dimension of the stator blades is 0.75D.

4. The open fan component according to claim 1, characterized in that, The actuator is a hydraulic actuator. The base is connected to a stator fixed load-bearing device through the hydraulic actuator. The hydraulic actuator includes an electro-hydraulic servo valve, an actuator, and a telescopic rod. The electro-hydraulic servo valve is electrically connected to an active noise controller, and controls the flow of the internal oil of the actuator by receiving the electrical signal of the active noise controller, thereby adjusting the actuator, so that the actuator changes the length of the telescopic rod to drive the stator blades to reciprocally move from the first position to the second position to switch between the first state and the second state.

5. The open fan component according to claim 4, wherein, The actuator can drive the telescopic rod, and the actuator is provided with a displacement sensor. The displacement sensor is electrically connected to the active noise controller and can real-time feedback the length parameter of the telescopic rod to the active noise controller.

6. The open fan component according to claim 4, characterized in that, The stator fixed load-bearing device provides a reserved space, and the reserved space provides a space for the hydraulic actuator to swing up and down on the stator fixed load-bearing device.

7. A noise reduction method, characterized in that, Using the open fan component according to any one of claims 1-6 for noise reduction of an open rotor engine.

8. The noise reduction method according to claim 7, wherein The open fan component is the open fan component described in any one of claims 4-6, and the noise reduction method includes the following steps: S100. Obtain the expected value Ref_L of the telescopic rod length parameter of the hydraulic actuator corresponding to different flight conditions; S200. The displacement sensor in the actuator of the hydraulic actuator feeds back the real-time length parameter Ins_L of the telescopic rod to the active noise controller in real time; the active noise controller performs real-time electrical signal control on the hydraulic servo valve according to the difference between Ref_L and Ins_L, so that Ins_L approaches Ref_L until the two are the same.

9. The noise reduction method according to claim 8, wherein The steps of S100 include: S101. Set the first radial dimension of the stator vane as the upper limit and the second radial dimension of the stator vane as the lower limit, and establish a function between the formed radial dimension interval and the flight conditions; S102. Configure the function in the active noise controller.

10. The noise reduction method according to claim 8, wherein The steps of S200 include: Perform real-time electrical signal control on the hydraulic servo valve. The hydraulic servo valve and the actuator are previously set to have oil passing through, so that different electrical signals will have different control effects on the oil, making Ins_L approach Ref_L until the two are the same.

11. An open rotor engine, characterized in that, It includes the open fan component described in any one of claims 1-6.

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