Open type rotor engine fan with adjustable pitch angle and manufacturing method

Abstract

The invention provides an open type rotor engine fan with an adjustable pitch angle and a manufacturing method. The fan comprises a hub and a blade, the blade comprises a blade handle and a blade body, and the blade body is supported on the hub through the blade handle. The blade body comprises a plurality of grid units which are connected with one another to form the blade body. The grid units comprise at least one rotating unit, and the rotating units can rotate in the axial direction of the blade body. The fan further comprises an adjusting mechanism, and the adjusting mechanism is connected with the rotating unit to control the rotating unit to rotate so as to change the pitch angle of the blade. According to the open type rotor engine fan with the adjustable pitch angle, the aerodynamic efficiency of all working condition points of the whole course can be improved.

Description

Technical Field

[0001] This invention relates to open rotor engines, and more particularly to an open rotor engine fan with an adjustable pitch angle and a method for manufacturing it. Background Technology

[0002] Propfan engines, also known as open rotor engines, are different from high-bypass turbofan engines widely used in civil aviation. Due to their significantly increased bypass ratio, open rotor engines (i.e., propfan engines) improve engine propulsion efficiency and greatly reduce fuel consumption.

[0003] Open rotor engines, lacking nacelles and thrust reversers, rely entirely on adjusting the blade pitch angle to achieve thrust reverser functionality. The ability to adjust the pitch angle in real-time according to different operating conditions along the flight path further enhances the efficiency of open rotor engines. Currently, common open fan configurations feature blades that rotate around the central axis of the blade stalk. These blades are supported on the hub by bearings, with the ends connected to a pitch angle adjustment mechanism to control the blade pitch angle.

[0004] However, due to the large size of open-type fan blades, their blade profiles exhibit significant radial twisting at different heights. In reality, the blade pitch angle will have different optimal design angles at different operating points and locations. However, common pitch angle adjustment mechanisms can only achieve the basic function of uniformly adjusting the pitch angle of the entire blade under a specific operating condition. In actual use, at various operating points along the flight path, only some blade profiles can be guaranteed to be at the optimal design angle. Therefore, there will always be some blade profiles at certain locations (such as the blade tip, blade root, leading edge, and trailing edge) that deviate from their optimal design angle, leading to a decrease in aerodynamic performance and even flow separation.

[0005] However, the current conventional design method is to optimize the aerodynamic design to make the blade airfoil at the optimal design angle at as many positions as possible under a specified test condition. However, this method requires a lot of manual time for iterative optimization, has high requirements for the accumulation of technical experience, and cannot guarantee that the blade will have high aerodynamic efficiency under all operating conditions of the flight path. Summary of the Invention

[0006] The purpose of this invention is to provide an open rotor engine fan with adjustable pitch angle and a manufacturing method thereof, which can improve the aerodynamic efficiency at all operating points along the entire route.

[0007] One aspect of the present invention provides an open rotor engine fan with adjustable pitch angle. The fan includes a hub and blades. Each blade includes a shank and a blade body, and the blade body is supported on the hub by the shank. The blade body includes multiple grid units, which are interconnected to form the blade body. Each grid unit includes at least one rotating unit, which is capable of rotating about the axial direction of the blade body. The fan also includes an adjustment mechanism connected to the rotating unit to control the rotation of the rotating unit, thereby changing the pitch angle of the blades.

[0008] In one embodiment, the rotating unit is provided with a rotating shaft, which is arranged along the axial direction of the blade; the adjusting mechanism is connected to the rotating shaft to control the rotation of the rotating shaft, thereby driving the rotating unit to rotate.

[0009] In one embodiment, the rotating shaft is disposed on the side edge of the rotating unit.

[0010] In one embodiment, the rotating unit is provided with a driving mechanism, which is disposed inside the rotating unit; the driving mechanism is connected to the rotating shaft and the adjusting mechanism, and the driving mechanism drives the rotating shaft to rotate under the control of the adjusting mechanism.

[0011] In one embodiment, the drive mechanism is one of a shape memory alloy, an electric drive device, and a hydraulic drive device.

[0012] In one embodiment, the blade stalk provides a hollow channel; the fan also includes a cable for connecting the adjustment mechanism and the drive mechanism; the cable passes through the hollow channel to connect the adjustment mechanism and the drive mechanism.

[0013] In one embodiment, the blades are made of a composite material; adjacent mesh cells are connected by adhesive bonding.

[0014] In one embodiment, the leaf blade includes a first grid unit, a first rotating unit, a second rotating unit, a third rotating unit, and a fourth rotating unit; the first rotating unit is located at the tip of the leading edge of the leaf, the second rotating unit is located at the root of the leading edge of the leaf, the third rotating unit is located at the tip of the trailing edge of the leaf, and the fourth rotating unit is located at the root of the trailing edge of the leaf; the first rotating unit, the second rotating unit, the third rotating unit, and the fourth rotating unit are all connected to the first grid unit.

[0015] In one embodiment, the outer surface of the leaf blade is covered with a thin film.

[0016] Another aspect of the present invention provides a method for manufacturing an open rotor engine fan with adjustable pitch angle, wherein the open rotor engine fan with adjustable pitch angle is an open rotor engine fan as described in any of the above embodiments, the manufacturing method comprising: dividing the blade into a plurality of grid units, the plurality of grid units including at least one rotatable rotating unit; assembling each of the rotating units and the grid units; and connecting the rotating units to an adjustment mechanism so that the adjustment mechanism can control the rotation of the rotating units.

[0017] The open rotor engine fan of this invention, with adjustable pitch angle, divides the blades into multiple grid units, allowing each blade in each grid unit to independently adjust its pitch angle in real time. Compared to conventional pitch angle adjustment devices that can only adjust the pitch angle of the entire blade, this invention enables precise adjustment of the open fan blade pitch angle, ensuring that the blades at any position are at their optimal design angle under any operating condition. This reduces the aerodynamic design iteration cycle, improves aerodynamic efficiency at all operating conditions along the entire route, and is structurally feasible with minimal modifications to the existing open fan engine structure. Attached Figure Description

[0018] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0019] Figure 1 This is a schematic diagram of an open fan;

[0020] Figure 2 yes Figure 1 A schematic diagram of the AA direction in the diagram;

[0021] Figure 3 This is a schematic diagram of an embodiment of an open rotor engine fan with adjustable pitch angle according to the present invention;

[0022] Figure 4 yes Figure 3 A partial schematic diagram of the fan of an open rotary engine is shown.

[0023] Figure 5 yes Figure 3 A schematic diagram of a preferred embodiment of the grid cell division of an open rotor engine fan is shown.

[0024] Figure 6 This is a schematic flowchart of an embodiment of a method for manufacturing an open rotor engine fan with adjustable pitch angle according to the present invention. Detailed Implementation

[0025] Propfan engines, also known as open rotor engines, are different from high-bypass turbofan engines widely used in civil aviation. Due to their significantly increased bypass ratio, open rotor engines (i.e., propfan engines) improve engine propulsion efficiency and greatly reduce fuel consumption.

[0026] Currently, the most common open-type fan configurations all have blades that can rotate around the central axis of the blade stalk. The blades are supported on the hub by bearings, and the ends are connected to the blade pitch angle adjustment mechanism to achieve the adjustment of the blade pitch angle.

[0027] However, due to the large size of open-type fan blades, their blade profiles exhibit significant radial twisting at different heights. In reality, the blade pitch angle will have different optimal design angles at different operating points and locations. However, common pitch angle adjustment mechanisms can only achieve the basic function of uniformly adjusting the pitch angle of the entire blade under a specific operating condition. In actual use, at various operating points along the flight path, only some blade profiles can be guaranteed to be at their optimal design angles. Therefore, there will always be some locations (such as the blade tip, blade root, leading edge, and trailing edge) where the blade profile deviates from its optimal design angle, leading to a decrease in aerodynamic performance and even flow separation.

[0028] However, the current conventional design method is to optimize the aerodynamic design to make the blade airfoil at the optimal design angle at as many positions as possible under a specified test condition. However, this method requires a lot of manual time for iterative optimization, has high requirements for the accumulation of technical experience, and cannot guarantee that the blade will have high aerodynamic efficiency under all operating conditions of the flight path.

[0029] The term "pitch angle" is the angle between the chord length of the blade section at 75% blade height and the frontal (circumferential) line. Figure 1 The structure of an open fan with a front-rotating, rear-stationary configuration is shown. For example... Figure 1 As shown, the moving blade 1 and the stationary blade 2 are arranged sequentially along the direction of the intake airflow. The intake cone 3 is located at the front end of the open fan, and the intake duct 4 inside is responsible for guiding air into the fan area, providing the necessary airflow for the fan's operation. The direction of the intake airflow is... Figure 1 In the X-axis direction of the engine, section AA is the airfoil section at 75% of the blade height.

[0030] Figure 2 A schematic diagram of section AA is shown to illustrate and explain the pitch angle. Figure 2 The XYZ axes only indicate direction; their positions are not the actual coordinates defined for an open-fan engine. In a Cartesian coordinate system, the X-axis represents the direction of the intake airflow, and the Z-axis (i.e.,...) represents the direction of the airflow. Figure 1 and Figure 2The rotation axis OO of the moving blade 1 or stationary blade 2 is perpendicular to the ground and pointing upwards. The direction of the Y-axis is determined by the right-hand rule. Figure 2 The blade profile shown is for illustrative purposes only. When the engine enters reverse thrust mode, the pitch angle will approach 0°, and when the engine enters feathering mode, the pitch angle will approach 90°.

[0031] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided to explain the invention and not to limit it. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the invention without departing from the scope or spirit thereof. For example, a feature shown or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, the invention is intended to cover these modifications and variations that fall within the scope of the appended claims and their equivalents.

[0032] As used herein, the term "axial" refers to the central axis of the blade or the direction parallel to the central axis of the blade. The terms "first," "second," "third," and "fourth" are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of individual components.

[0033] Figure 3 and Figure 4 The structure of an embodiment of the open rotor engine fan with adjustable pitch angle according to the present invention is shown. Figure 3 and Figure 4 As shown, the open rotor engine fan includes an intake cone 10, a blade shank 110, a bearing 20, a hub 30, a bearing dust cover 40, blades 100, and a conventional pitch angle adjustment device 50. The blade 100 includes a blade shank 110 and a blade body 120. The blade shank 110 is supported on the hub 30 by two rows of blade shank bearings 20, and consequently, the blade body 120 and the entire blade 100 are supported on the hub 30. The conventional pitch angle adjustment device 50 is connected to the blade shank 110, allowing for overall pitch angle adjustment.

[0034] Specifically, the rocker arm 51 of the conventional pitch angle adjustment device 50 is connected to the outside of the blade shank 110 of the blade 100, enabling the entire blade 100 to rotate around the central axis OO, thus achieving reverse thrust and pitch angle adjustment functions. The structure and control method for implementing this basic function are consistent with the configuration of a conventional variable pitch angle open fan, ensuring the realization of the basic pitch angle adjustment function, and will not be elaborated further.

[0035] The fan blade 120 of the present invention includes a plurality of grid units 121, which are interconnected to form the blade 120. The blade 120 can be divided into a plurality of grid units 121 according to aerodynamic design requirements. The number of grid units 121 is at least two; for example, it can be divided into two parts: the front side of the blade and the rear side of the blade, or it can be divided into two parts: the upper part of the blade and the lower part of the blade.

[0036] The plurality of grid cells 121 include at least one rotating cell, which is capable of rotating about the axial direction of the blade 120. That is, each rotating cell is designed to rotate about a specific axis of rotation O'-O'. The axis of rotation O'-O' is parallel to the central axis of rotation OO of the blade 120.

[0037] The fan of the present invention also includes an adjustment mechanism 200, which is connected to the rotating unit to control the rotation of the rotating unit, thereby changing the blade pitch angle of the blades 100. The adjustment mechanism 200 can be fixed to the hub 30.

[0038] The open rotor engine fan of the present invention with adjustable pitch angle divides the blade 100 into multiple grid units 121, so that the blade 100 in each grid unit 121 can independently adjust the pitch angle in real time. Compared with the conventional pitch angle adjustment device 50, which can only adjust the pitch angle of the entire blade 100, the present invention can achieve precise adjustment of the pitch angle of the open fan blade 100, ensuring that the blade 100 at any position is at the optimal design angle under any operating condition, reducing the aerodynamic design iteration cycle, improving the aerodynamic efficiency at all operating conditions along the entire route, and has structural feasibility with minimal modifications to the existing open fan engine structure.

[0039] It should be noted that, although Figure 3 and Figure 4 The adjustment mechanism 200 is connected to the rotor blades 100 of the open-type fan. The open-type rotor engine fan of this invention is also fully applicable to the precise pitch adjustment of the stator blades 100 of the open-type fan, that is, this invention is also applicable to... Figure 1 The open fan configuration shown, with its "front rotor and rear stator," can also be applied to various blades that require precise adjustment of the blade pitch angle. Its functional principle and implementation structure are basically the same, and this invention does not impose any limitations on it.

[0040] Specifically, the rotating unit is equipped with a rotating shaft (not shown), which is arranged along the axial direction of the blade 120. An adjusting mechanism 200 is connected to the rotating shaft to control its rotation, thereby driving the rotating unit to rotate. The rotation axis O'-O' of the rotating unit can be located at any desired position on the rotating unit. Optionally, the rotating shaft is located at the side edge or central axis of the rotating unit.

[0041] When the rotating shaft is located on the side edge of the rotating unit, the rotating unit and the adjacent grid unit 121 can be connected by a hinge.

[0042] In one embodiment, the rotating unit is provided with a drive mechanism (not shown), which is located inside the rotating unit. Considering the aerodynamic design requirements of the blade 100, the drive mechanism cannot be located on the surface of the blade 100. The blade 100 has a certain thickness, and a sandwich structure can be designed to house the drive mechanism inside. The drive mechanism connects the rotating shaft and the adjusting mechanism 200, and drives the rotating shaft to rotate under the control of the adjusting mechanism 200.

[0043] The regulating mechanism 200 can output corresponding control signals at different operating points along the entire route according to the instructions issued by the engine controller.

[0044] The drive mechanism is one of the following: shape memory alloy, electric drive, or hydraulic drive. These types of drive mechanisms can perform precise actuation control based on received control signals, ensuring that the propeller pitch angle is always at the optimal design angle.

[0045] like Figure 3 and Figure 4 As shown, the blade holder 110 provides a hollow channel 111. The hollow design of the blade holder 110 allows for weight reduction of the blade 100. The fan also includes a cable 300 for connecting the adjustment mechanism 200 and the drive mechanism. The cable 300 passes through the hollow channel 111 to connect the adjustment mechanism 200 and the drive mechanism. Signal commands from the engine controller are transmitted to the drive mechanism of each rotating unit via the cable 300 passing through the blade holder 110 of the blade 100, enabling the pitch angle adjustment function of each grid unit 121.

[0046] Optionally, the cable 300 output by the adjustment mechanism 200 can be designed to be bundled through the blade 100 stalk 110, connected to the blade 100 body 120, and then dispersed through a corresponding structure to connect to their respective designated grid units 121.

[0047] The connection method between adjacent grid units 121 can be selected according to the material of the blade 100. In one embodiment, the blade 100 is made of composite material. The composite material can be carbon fiber reinforced composite material. In this embodiment, adjacent grid units 121 are connected by flexible adhesive bonding, so that the connection joint has a certain degree of adjustability while ensuring the strength of the blade 100.

[0048] Understandably, the fewer grid cells 121 the blade 120 is divided into, the better the stability and reliability of the blade 120 formed by the interconnection of these grid cells 121; conversely, the more grid cells 121 the blade 120 is divided into, the higher the accuracy of pitch angle adjustment at any position on the blade 120. Therefore, the principle for dividing the grid cells 121 of the blade 120 can be a compromise between the above two principles.

[0049] In actual use of the open fan blade 100, at various operating points along the flight path, the blade profile of the blade 100 at the blade tip, blade root, leading edge, and trailing edge deviates from its optimal design angle, which leads to a decrease in its aerodynamic performance and even flow separation.

[0050] like Figure 5 As shown, in a specific embodiment, the blade 120 is divided into five grid units 121, specifically including a first grid unit 121a, a first rotating unit 121b, a second rotating unit 121c, a third rotating unit 121d, and a fourth rotating unit 121e. The first rotating unit 121b is located at the tip of the leading edge of the blade 100, the second rotating unit 121c is located at the root of the leading edge of the blade 100, the third rotating unit 121d is located at the tip of the trailing edge of the blade 100, and the fourth rotating unit 121e is located at the root of the trailing edge of the blade 100. The first rotating unit 121b, the second rotating unit 121c, the third rotating unit 121d, and the fourth rotating unit 121e are all connected to the first grid unit 121a. That is, local positions at the tips and roots of the leading and trailing edges of the blade 100 are designated as grid units 121 with adjustable pitch angles, which can achieve optimal aerodynamic performance of the blade 100.

[0051] The first grid unit 121a can have its pitch angle adjusted by a conventional pitch angle adjustment device 50.

[0052] In one embodiment, the outer surface of the blade 120 is covered with a thin film, which can reduce surface aerodynamic drag and prevent flow separation of the mainstream airflow at the joints of the grid cells 121. The thin film may be a composite material with a small thickness.

[0053] Figure 6 A flowchart illustrating a method for manufacturing an open rotor engine fan with adjustable pitch angle according to the present invention is provided. The open rotor engine fan with adjustable pitch angle is the open rotor engine fan described in any of the above embodiments.

[0054] like Figure 6 As shown, the manufacturing method of the present invention includes steps S100 to S300:

[0055] In step S100, the blade 120 is divided into multiple grid cells 121, each grid cell 121 including at least one rotatable rotating cell. The rotating cell is capable of rotating about the axial direction of the blade 120.

[0056] In step S200, each rotating unit and the mesh unit 121 are assembled. The drive mechanism can be assembled into each rotating unit first, with the control cable 300 connector pre-installed, before connecting each rotating unit and the mesh unit 121. The specific connection method can be selected based on the material of the blade 100.

[0057] In step S300, the rotating unit is connected to the adjusting mechanism 200 so that the adjusting mechanism 200 can control the rotation of the rotating unit. The cables 300 are bundled and extend from the blade stalk 110. When the blade 100 is assembled as a whole, only the control cables 300 pre-existing at the end of the blade stalk 110 need to be connected to the adjusting mechanism 200.

[0058] Compared with the conventional pitch angle adjustment mechanism 200, this invention enables precise adjustment of the blade 100 in 100-region areas, improving aerodynamic efficiency. The adjustment mechanism 200 of this invention divides the blade 100 blade body 120 into grid units 121 as needed. The drive mechanism controls each blade 100 grid unit 121 to precisely adjust the pitch angle in real time. This further improves aerodynamic efficiency on top of the existing overall adjustment of the blade 100's pitch angle, with minimal modifications to the existing open fan's peripheral structure.

[0059] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. An open rotor engine fan with adjustable pitch angle, the fan comprising a hub and blades, the blades comprising a shank and a blade body, the blade body being supported on the hub by the shank; Its features are, The blade comprises multiple grid units, which are interconnected to form the blade. The plurality of grid cells include at least one rotating unit, which is capable of rotating about the axial direction of the blade. The fan also includes an adjustment mechanism connected to the rotation unit to control the rotation of the rotation unit.

2. The open rotor engine fan as described in claim 1, characterized in that, The rotating unit is provided with a rotating shaft, which is arranged along the axial direction of the blade. The adjusting mechanism is connected to the rotating shaft to control the rotation of the rotating shaft, thereby driving the rotating unit to rotate.

3. The open rotor engine fan as described in claim 2, characterized in that, The rotating shaft is located on the side edge of the rotating unit.

4. The open rotor engine fan as described in claim 2 or 3, characterized in that, The rotating unit is provided with a driving mechanism, which is located inside the rotating unit; The drive mechanism connects the rotating shaft and the adjustment mechanism, and the drive mechanism drives the rotating shaft to rotate under the control of the adjustment mechanism.

5. The open rotor engine fan as described in claim 4, characterized in that, The drive mechanism is one of shape memory alloy, electric drive device, and hydraulic drive device.

6. The open rotor engine fan as described in claim 4, characterized in that, The petiole provides a hollow channel; The fan also includes cables for connecting the adjustment mechanism and the drive mechanism; The cable passes through the hollow channel and connects the adjustment mechanism and the drive mechanism.

7. The open rotor engine fan as described in any one of claims 1 to 3, characterized in that, The blades are made of composite materials; Adjacent grid cells are connected by adhesive bonding.

8. The open rotor engine fan as described in any one of claims 1 to 3, characterized in that, The blade includes a first grid unit, a first rotating unit, a second rotating unit, a third rotating unit, and a fourth rotating unit; The first rotating unit is located at the tip of the blade at the leading edge, the second rotating unit is located at the root of the blade at the leading edge, the third rotating unit is located at the tip of the blade at the trailing edge, and the fourth rotating unit is located at the root of the blade at the trailing edge. The first rotating unit, the second rotating unit, the third rotating unit, and the fourth rotating unit are all connected to the first mesh unit.

9. The open rotor engine fan as described in any one of claims 1 to 3, characterized in that, The outer surface of the leaf is covered with a thin film.

10. A method for manufacturing an open rotor engine fan with adjustable pitch angle, characterized in that, The open rotor engine fan with adjustable pitch angle is the open rotor engine fan as described in any one of claims 1-9. The manufacturing method includes: The blade is divided into multiple grid units, and the multiple grid units include at least one rotatable rotating unit; Assemble each of the aforementioned rotating units and the aforementioned mesh units; The rotating unit is connected to an adjusting mechanism so that the adjusting mechanism can control the rotation of the rotating unit.

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