Wide working condition adaptive flexible adjustable blade

Abstract

The application provides a wide-condition-adaptive flexible adjustable blade, and belongs to the technical field of gas turbine engines. The adjustable blade comprises a fixed section, a rotating shaft, a framework assembly, a rolling shaft and a flexible skin. The flexible skin attached to the side surface of the fixed section corresponding to the blade pressure surface forms the pressure surface profile of the fixed part. The flexible skin attached to the side surface of the fixed section corresponding to the blade suction surface forms the suction surface profile of the fixed part. The framework assembly is movably connected to the part of the flexible skin corresponding to the blade pressure surface, and the framework assembly is movably connected to the part of the flexible skin corresponding to the blade suction surface to define the pressure surface profile and the suction surface profile of the movable part, respectively. The framework assembly is configured such that when the rotating shaft is driven to rotate around the axis of the rotating shaft by an external force, the framework assembly rotates around the axis of the rotating shaft along with the rotating shaft, and drives the movable part to rotate around the axis of the rotating shaft, so as to adjust the bending angle of the blade. The stator total pressure recovery coefficient of the blade at different adjustment angles is improved.

Description

Technical Field

[0001] This application relates to the field of gas turbine engines, and in particular to a flexible, adjustable blade with wide operating conditions. Background Technology

[0002] Modern aero-engines' wide operating range demands a wide range of flow rate and pressure ratio adjustment for their compression systems. For traditional fan and compressor configurations, the characteristic curve is fixed at a given speed, and the high-efficiency band formed at different speeds is very narrow, failing to meet the requirements for wide-range adjustment. Adjusting the rotor flow direction by changing the installation angle of the stator blades in front of the fan / compressor rotor is an effective means of performance regulation. However, when the stator blade adjustment angle is too large, the angle of attack increases accordingly, leading to an increase in the total pressure loss of the adjustable blades and disrupting the uniformity and stability of the rotor flow, thus limiting its adjustment range.

[0003] To adapt to the wide range of blade airflow angle requirements, the variable camber blade design method, based on the concept of adjustable blades, has emerged. By adjusting the camber distribution of the stator blades, the exit airflow angle can be optimized, effectively expanding the operating range. Traditional variable camber blades consist of two sections: the front section remains fixed, while the rear section changes the airflow direction by rotating around its axis. This adjustment method has the following two problems: First, there are gaps in the rotating shaft, which can induce significant flow losses at large turning angles; second, it is difficult to maintain the geometric smoothness of the blade surface profile after rotation, further increasing flow losses and reducing aerodynamic performance. Summary of the Invention

[0004] In view of this, this application provides a flexible adjustable blade with wide operating conditions, which solves the problems in the prior art, reduces the airflow loss of the adjustable blade at large adjustment angles, and improves the stator total pressure recovery coefficient of the blade at different adjustment angles.

[0005] The technical solution for a flexible, adjustable blade with wide operating conditions provided in this application is as follows: A flexible adjustable blade adaptable to a wide range of operating conditions includes: a fixed section, a rotating shaft, a frame assembly, a roller, and a flexible skin; The fixed section corresponds to the part of the blade near the leading edge of the blade. The rotating shaft is parallel to the blade height direction and is rotatably mounted on the side of the fixed section opposite to the leading edge of the blade. The skeleton assembly is fixedly connected to the rotating shaft, and the skeleton assembly extends from the fixed section to the trailing edge of the blade. The axis of the roller is parallel to that of the rotating shaft and is rotatably mounted on one end of the skeleton assembly near the trailing edge of the blade. The flexible skin wraps around the fixed section, the skeleton assembly, and the outer periphery of the roller. The part of the flexible skin corresponding to the fixed section serves as a fixed part and is attached to the surface of the fixed section. The part of the flexible skin corresponding to the skeleton assembly and the roller serves as a movable part. The outer surface of the flexible skin forms the aerodynamic profile of the blade. The end of the fixed section opposite to the rotating shaft supports the flexible skin and defines the side profile of the leading edge of the blade. The circumferential side of the roller opposite to the skeleton assembly is attached to and supports the flexible skin and defines the side profile of the trailing edge of the blade. The flexible skin attached to the side of the blade pressure surface of the fixed section forms the pressure surface profile of the fixed part, and the flexible skin attached to the side of the blade suction surface of the fixed section forms the suction surface profile of the fixed part. The skeleton assembly is partially movably connected to the flexible skin corresponding to the blade pressure surface to define the pressure surface profile of the movable part, and the skeleton assembly is partially movably connected to the flexible skin corresponding to the blade suction surface to define the suction surface profile of the movable part. The skeleton assembly is configured such that when the rotating shaft is externally driven to rotate around the axis of the rotating shaft, the skeleton assembly rotates with the rotating shaft around the axis of the rotating shaft, thereby driving the movable part to rotate around the axis of the rotating shaft to adjust the bending angle of the blade.

[0006] Optionally, the skeleton component includes: A first main rod and a second main rod, one end of the first main rod and the second main rod are fixedly connected to the rotating shaft, the other end of the first main rod extends toward the blade pressure surface, and the other end of the second main rod extends toward the blade suction surface; The pressure surface branch rod is hinged to the end of the first main rod away from the rotating shaft; The pressure surface boss is fixed on the inner wall of the pressure surface of the blade corresponding to the movable part, and the end of the pressure surface branch rod away from the first main rod is hinged to the pressure surface boss. The suction-force branch rod is hinged to the end of the second main rod away from the pivot. A suction surface boss is fixed on the inner wall of the suction surface of the blade corresponding to the movable part, and the end of the suction surface branch rod away from the second main rod is hinged to the suction surface boss; The trailing edge support rod is fixedly connected to the end of the second main rod away from the rotating shaft. The end of the trailing edge support rod away from the second main rod extends to the trailing edge of the blade. The roller is rotatably mounted on the trailing edge support rod. The hinge shafts and rotation shafts at both ends of the pressure surface branch rod and the suction surface branch rod are parallel, and the pressure surface boss is closer to the blade trailing edge than the suction surface boss.

[0007] Optionally, a pressure surface stop is provided at the end of the first main rod that is hinged to the pressure surface branch rod. The pressure surface stop is located on the side of the pressure surface branch rod facing the suction surface of the blade. When the blade is bent to the maximum designed bending angle, the first main rod and the pressure surface branch rod are on a straight line, and the pressure surface branch rod abuts against the pressure surface stop, restricting the pressure surface branch rod from rotating to the side of the first main rod facing the suction surface of the blade.

[0008] Optionally, a suction surface stop is provided at the end of the second main rod that is hinged to the suction surface branch rod. The suction surface stop is located on the side of the suction surface branch rod facing the blade pressure surface. When the blade is in the initial state, the second main rod and the suction surface branch rod are on a straight line, and the suction surface branch rod abuts against the suction surface stop, restricting the suction surface branch rod from rotating to the side of the second main rod facing the blade pressure surface.

[0009] Optionally, the axis of the rotating shaft is located at the center of the blade thickness direction relative to the chord length position of the rotating shaft.

[0010] Optionally, the relative chord length position corresponding to the end face of the fixed section opposite to the leading edge of the blade coincides with the relative chord length position corresponding to the maximum thickness position of the blade in its initial state.

[0011] Optionally, the suction surface boss is an elongated strip extending along the axial direction of the rotation axis, and the center position of the suction surface boss in the width direction corresponds to the point of maximum curvature on the suction surface of the blade when the blade is at its maximum designed bending angle.

[0012] Optionally, the pressure surface boss is an elongated strip extending along the axial direction of the rotation axis, and the center position of the pressure surface boss in the width direction corresponds to the point of maximum curvature on the pressure surface of the blade when the blade is at its maximum designed bending angle.

[0013] In summary, this application includes the following beneficial technical effects: When the rotating shaft of this application rotates to different angles and the blades present different bending angles through the rotation of the skeleton assembly, the aerodynamic profile of the blades is always composed of a flexible skin. The flexible skin is smooth and continuous, eliminating gaps at the rotating mechanism and avoiding flow losses caused by gap leakage. It achieves continuous deformation of the blade aerodynamic profile within a wide angle range, avoiding the problem of uneven geometric profiles of the blade suction and pressure surfaces at the rotating mechanism in traditional variable camber blades, and avoiding flow losses caused by discontinuous curvature of the blade surface geometry. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 A schematic diagram of the overall structure of a flexible, adjustable blade with wide operating conditions when the blade is in its initial state. Figure 2 A schematic diagram of the overall structure of a flexible, adjustable blade that adapts to a wide range of operating conditions when the blade is at its maximum design bending angle. Figure 3 This is a schematic diagram of the fixed section and the frame assembly when the blade is in its initial state. Figure 4 A schematic diagram of the fixed section and frame assembly when the blade is at its maximum design bending angle; Figure 5 This is a schematic diagram of the nodes of the pivot and skeleton components in a Cartesian coordinate system.

[0016] Explanation of reference numerals in the attached drawings: 1. Fixed section; 2. Fixing element; 3. Rotating shaft; 4. Second main rod; 5. First main rod; 6. Suction surface stop block; 7. Suction surface branch rod; 8. Suction surface boss; 9. Flexible skin; 10. Tail edge support rod; 11. Pressure surface stop block; 12. Roller; 13. Pressure surface boss; 14. Pressure surface branch rod; 15. Bushing; 16. Screw; 17. Hinge shaft. Detailed Implementation

[0017] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0018] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0020] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0021] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0022] This application provides a flexible, adjustable blade with wide operating conditions. In this embodiment, the blade is a stator blade.

[0023] like Figures 1 to 4 As shown, a flexible adjustable blade adaptable to a wide range of operating conditions includes: a fixed section 1, a rotating shaft 3, a frame assembly, a roller 12, and a flexible skin 9.

[0024] The fixed section 1 corresponds to the part of the blade near the leading edge of the blade. The fixed section 1 is fixed relative to the stator casing. The rotating shaft 3 is parallel to the blade height direction. The rotating shaft 3 is rotatably mounted on the side of the fixed section 1 facing away from the leading edge of the blade via a fixing member 2. The fixing member 2 is fixed to the fixed section 1 by screws 16. The rotating shaft 3 and the fixing member 2 are rotatably connected by a bearing. The skeleton assembly is fixedly connected to the rotating shaft 3, and the skeleton assembly extends from the fixed section 1 towards the trailing edge of the blade. The axis of the roller 12 is parallel to that of the rotating shaft 3. The roller 12 is rotatably mounted at one end of the skeleton assembly near the trailing edge of the blade. The relative chord length position corresponding to the end face of the fixed section 1 facing away from the leading edge of the blade coincides with the relative chord length position corresponding to the maximum thickness position of the blade in its initial state. The axis of the rotating shaft 3 is located at the center position of the blade thickness direction at the relative chord length position of the rotating shaft 3. That is, the rotating shaft 3 is mounted at the center position of the corresponding blade thickness direction.

[0025] The flexible skin 9 wraps around the fixed section 1, the skeleton assembly, and the roller 12. The portion of the flexible skin 9 corresponding to the fixed section 1 serves as a fixed part, attached and fixed to the surface of the fixed section 1. The portion of the flexible skin 9 corresponding to the skeleton assembly and the roller 12 serves as a movable part. The outer surface of the flexible skin 9 forms the aerodynamic profile of the blade. The end of the fixed section 1 opposite to the rotating shaft 3 supports the flexible skin 9 and defines the leading edge profile of the blade. The circumferential side of the roller 12 opposite to the skeleton assembly is attached to and supports the flexible skin 9, defining the trailing edge profile of the blade. The flexible skin 9 attached to the side of the fixed section 1 corresponding to the pressure surface of the blade forms the pressure surface profile of the fixed part. The flexible skin 9 attached to the side of the fixed section 1 corresponding to the suction surface of the blade forms the suction surface profile of the fixed part. The skeleton assembly is movably connected to the portion of the flexible skin 9 corresponding to the pressure surface of the blade to define the pressure surface profile of the movable part. The skeleton assembly is movably connected to the portion of the flexible skin 9 corresponding to the suction surface of the blade to define the suction surface profile of the movable part.

[0026] The skeleton assembly is configured such that when the rotating shaft 3 is externally driven to rotate around the axis of the rotating shaft 3, the skeleton assembly rotates with the rotating shaft 3 around the axis of the rotating shaft 3, thereby driving the movable part to rotate around the axis of the rotating shaft 3 to adjust the bending angle of the blade.

[0027] When the rotating shaft 3 of this application rotates to different angles and the blade presents different bending angles through the rotation of the skeleton assembly, the aerodynamic profile of the blade is always composed of the flexible skin 9. The flexible skin 9 is smooth and continuous, eliminating the gaps at the rotating mechanism and avoiding flow loss caused by gap leakage. It realizes continuous deformation of the blade aerodynamic profile within a wide angle range, avoiding the problem of uneven geometric profiles of the blade suction surface and blade pressure surface at the rotating mechanism in traditional variable camber blades, and avoiding flow loss caused by discontinuity in the curvature of the blade surface geometry.

[0028] The skeleton component described in this embodiment includes: A first main rod 5 and a second main rod 4, one end of the first main rod 5 and the second main rod 4 are fixedly connected by a bushing 15 and a rotating shaft 3, the other end of the first main rod 5 extends toward the blade pressure surface, and the other end of the second main rod 4 extends toward the blade suction surface. The pressure surface branch rod 14 is hinged to the end of the first main rod 5 away from the rotating shaft 3; The pressure surface boss 13 is fixed on the inner wall of the pressure surface of the blade corresponding to the movable part, and the end of the pressure surface branch rod 14 away from the first main rod 5 is hinged to the pressure surface boss 13. The suction surface branch rod 7 is hinged to the end of the second main rod 4 away from the rotating shaft 3; The suction surface boss 8 is fixed on the inner wall of the suction surface of the blade corresponding to the movable part, and the end of the suction surface branch rod 7 away from the second main rod 4 is hinged to the suction surface boss 8. The trailing edge support rod 10 is fixedly connected to the end of the second main rod 4 away from the rotating shaft 3. The end of the trailing edge support rod 10 away from the second main rod 4 extends to the trailing edge of the blade. The roller 12 is rotatably mounted on the trailing edge support rod 10. The hinge shafts 17 and rotating shafts 3 at both ends of the pressure surface branch rod 14 and the suction surface branch rod 7 are parallel, and the pressure surface boss 13 is closer to the blade trailing edge than the suction surface boss 8.

[0029] As the blade bends from its initial state towards the maximum designed bending angle, the angle between the pressure surface branch rod 14 and the first main rod 5 gradually increases, the angle between the suction surface branch rod 7 and the trailing edge support rod 10 gradually increases, and the angle between the suction surface branch rod 7 and the second main rod 4 gradually increases. The fixed section 1, the second main rod 4, the trailing edge support rod 10, and the roller 12 primarily limit the overall bending trend of the flexible skin 9's moving parts. When the blade is bent from its initial state towards the maximum designed bending angle, the entire blade bends towards the pressure surface side. When the blade needs to be bent from its initial state to its maximum designed bending angle, the drive shaft 3 rotates towards the pressure surface of the blade. The shaft 3 drives the first main rod 5, the second main rod 4, and the trailing edge support rod 10 to rotate directly, forming the main driving force for bending the flexible skin 9. This causes the trailing edge of the blade to rotate relative to the leading edge. Simultaneously, the rotation of the second main rod 4 towards the pressure surface pulls the suction surface branch rod 7 and the suction surface boss 8 to shift towards the pressure surface, providing support and shaping for the suction surface profile of the movable part. The rotation of the first main rod 5 towards the side opposite to the suction surface pulls the pressure surface branch rod 14 and the pressure surface boss 13 to rotate towards the side opposite to the suction surface, again providing support and shaping for the pressure surface profile of the movable part. This achieves the follow-up movement and continuous outer surface of the flexible skin 9 during the blade bending adjustment process.

[0030] The shape and curvature of the pressure surface boss 13 that fits with the movable part match the design surface of the corresponding part of the blade, so that the curvature of the outer surface of the flexible skin 9 of the movable part at the support position of the pressure surface boss 13 meets the blade design requirements; the shape and curvature of the suction surface boss 8 that fits with the movable part match the design surface of the corresponding part of the blade, so that the curvature of the outer surface of the flexible skin 9 of the movable part at the suction surface boss 8 meets the blade design requirements. In one embodiment, during the bending process, the curvature of the blade profile at the pressure surface boss 13 and suction surface boss 8 remains almost unchanged. To ensure that the blade profile meets the design requirements throughout the entire range of motion from the initial state to the maximum design bending angle, and to prevent the flexible skin 9 from becoming loose or collapsing, in this embodiment, an elastic flexible skin 9 is used. Corresponding bending prestress is applied to the flexible skin 9 at the pressure surface boss 13 and suction surface boss 8. The pressure surface branch rod 14 supports the flexible skin 9 through the pressure surface boss 13, and the suction surface branch rod 7 supports the flexible skin 9 through the suction surface boss 8. Combined with the bending prestress at the corresponding position of the flexible skin 9, the flexible skin 9 maintains the curvature that meets the blade design requirements at different bending angles of the blade.

[0031] A pressure surface stop 11 is provided at the end of the first main rod 5 that is hinged to the pressure surface branch rod 14. The pressure surface stop 11 is located on the side of the pressure surface branch rod 14 facing the blade suction surface. When the blade is bent to the maximum designed bending angle, the first main rod 5 and the pressure surface branch rod 14 are in a straight line, and the pressure surface branch rod 14 abuts against the pressure surface stop 11, restricting the pressure surface branch rod 14 from rotating to the side of the first main rod 5 facing the blade suction surface. A suction surface stop 6 is provided at the end of the second main rod 4 that is hinged to the suction surface branch rod 7. The suction surface stop 6 is located on the side of the suction surface branch rod 7 facing the blade pressure surface. When the blade is in the initial state, the second main rod 4 and the suction surface branch rod 7 are in a straight line, and the suction surface branch rod 7 abuts against the suction surface stop 6, restricting the suction surface branch rod 7 from rotating to the side of the second main rod 4 facing the blade pressure surface.

[0032] In this embodiment, when the blade bends from its initial state to its maximum designed bending angle, the first main rod 5 and the pressure surface branch rod 14 are collinear under the constraint of the pressure surface stop 11. This creates a dead-point structure at the positions of the first main rod 5 and the pressure surface branch rod 14, stabilizing the structure of the frame assembly and the bending angle of the blade. When the blade returns to its initial state from its maximum designed bending angle, the second main rod 4 and the suction surface branch rod 7 are collinear under the constraint of the suction surface stop 6. This creates a dead-point structure at the positions of the second main rod 4 and the suction surface branch rod 7, stabilizing the structure of the frame assembly and the bending angle of the blade.

[0033] In one embodiment, the suction surface boss 8 and the pressure surface boss 13 are elongated strips extending along the axial direction of the rotating shaft 3. The center position of the pressure surface boss 13 in the width direction corresponds to the point of maximum curvature on the pressure surface of the blade when the blade is at the maximum design bending angle, and the center position of the suction surface boss 8 in the width direction corresponds to the point of maximum curvature on the suction surface of the blade when the blade is at the maximum design bending angle.

[0034] In other embodiments, the positions of the pressure surface boss 13 and the suction surface boss 8 can be adjusted according to actual needs. This application provides a method for determining the positions, key dimensions, and key angle parameters of the pressure surface boss 13 and the suction surface boss 8 of the skeleton assembly in other embodiments, as follows: Step 1: Define the line on the outer surface of the flexible skin 9 corresponding to the center line in the width direction of the suction surface boss 8 as the suction surface mounting line, define the line on the outer surface of the flexible skin 9 corresponding to the center line in the width direction of the pressure surface boss 13 as the pressure surface mounting line, and define the center line of the suction surface boss 8 and the center line of the pressure surface boss 13 as parallel to the axis of the rotating shaft 3.

[0035] Step 2: Determine the blade profile and maximum design bending angle in the initial state. The blade profile in the initial state is generated by combining a quadratic curve with a cubic curve thickness distribution and the design chord length. Specifically, a smooth mid-curve curve can be determined by giving the inlet geometry, outlet geometry, and maximum deflection position. The thickness distribution of the blade profile can be determined by giving parameters such as the leading edge thickness, trailing edge thickness, maximum thickness, and maximum thickness position. Combined with the chord length in the initial state, the blade profile in the initial state can be determined. Alternatively, B-spline interpolation can be used to parameterize the basic blade profile. Increasing the number of B-spline control points increases the design degrees of freedom, achieving multi-degree-of-freedom blade profile optimization and obtaining the blade profile in the initial state. The specific method for determining the blade profile in the initial state can be determined according to actual needs. In one embodiment, the maximum design bending angle is 15°.

[0036] Step 3: Determine the overall ideal mid-curve of the blade at the maximum design bending angle based on the relative chord length. Based on the overall ideal mid-curve and the thickness distribution of the blade in its initial state, determine the expected blade profile at the maximum design bending angle. The overall ideal mid-curve is obtained by combining the mid-curve corresponding to the fixed part of the blade in its initial state and the ideal mid-curve corresponding to the moving part of the blade at the maximum design bending angle. Both the mid-curve corresponding to the fixed part and the ideal mid-curve corresponding to the moving part of the blade in its initial state are quadratic curves. Specifically, the front end of the ideal mid-curve corresponding to the moving part of the blade at the maximum design bending angle has the same geometric angle and slope as the rear end of the mid-curve corresponding to the fixed part of the blade in its initial state. The exit geometric angle of the ideal mid-curve corresponding to the moving part of the blade at the maximum design bending angle is determined by the maximum design bending angle, ensuring the continuity of the curvature of the overall ideal mid-curve at the connection point between the fixed and moving parts, as well as the maximum thickness distribution.

[0037] The specific method for step 3 is as follows: Step 31: Superimpose the overall ideal arc with the thickness distribution of the blade in the initial state to obtain the blade profile based on the relative chord length position at the maximum design bending angle. Establish an independent Cartesian coordinate system with the leading edge of the blade as the origin. Obtain the coordinates of several discrete points on the blade profile based on the relative chord length position at the maximum design bending angle in the independent Cartesian coordinate system. Fit the blade profile function based on the relative chord length position at the maximum design bending angle by B-spline curve or non-uniform rational B-spline. Based on the blade profile function based on the relative chord length position at the maximum design bending angle, obtain the relationship between the ordinate of the points on the blade profile at the maximum design bending angle and the relative chord length position in the independent Cartesian coordinate system, and record it as an intermediate expression. Step 32, let the x-coordinate of the blade trailing edge point in an independent Cartesian coordinate system be (where x is the x-coordinate of the blade trailing edge point at the maximum design bending angle). Transform the relative chord length position in the intermediate expression with The relevant actual x-coordinate position is recorded as the preliminary expected expression; Step 33: Based on the preliminary expected expression, determine the first related equation for the total length of the blade profile pressure surface and the abscissa of the blade at the maximum design bending angle, and the second related equation for the total length of the blade profile suction surface and the abscissa of the blade at the maximum design bending angle. Then, combine the sum of the total length of the blade profile pressure surface and the total length of the blade profile suction surface with the total length of the flexible skin 9, solve the abscissa of the blade trailing edge point in the independent plane rectangular coordinate system at the maximum design bending angle, and combine the ordinate of the blade trailing edge point and the coordinate of the blade leading edge point in the independent plane rectangular coordinate system to determine the chord length of the blade at the maximum design bending angle. Step 34: Based on the chord length of the blade at the maximum design bending angle, convert the relative chord length position in the intermediate expression into the actual abscissa value in an independent plane rectangular coordinate system. Obtain the relationship between the ordinate and abscissa of the point on the blade profile at the maximum design bending angle in the independent plane rectangular coordinate system, determine the final expected expression, and determine the expected blade profile at the maximum design bending angle based on the final expected expression.

[0038] like Figure 5 As shown, in step 4, a global planar rectangular coordinate system is established with a point on the axis of the rotating shaft 3 as the origin O. The x-axis and y-axis of the global planar rectangular coordinate system are perpendicular to the axis of the rotating shaft 3.

[0039] Step 5: In the global Cartesian coordinate system, ensure that a fixed segment of the blade profile in the initial state coincides with the expected blade profile at the maximum design bending angle. Obtain the coordinates of several discrete points on the blade profile in the initial state and the expected blade profile at the maximum design bending angle in the global Cartesian coordinate system. Obtain the blade profile function in the initial state and the expected blade profile at the maximum design bending angle by fitting B-spline curves or non-uniform rational B-splines, respectively. Based on the blade profile function in the initial state, obtain the relationship between the ordinate and abscissa of the points on the blade profile in the initial state in the global Cartesian coordinate system, and record it as the initial expression. Based on the expected blade profile function at the maximum design bending angle, obtain the relationship between the ordinate and abscissa of the points on the blade profile at the maximum design bending angle in the global Cartesian coordinate system, and record it as the maximum bending expression.

[0040] Step 6: Determine the radius of roller 12, the axis coordinates of roller 12 in the initial state and at the maximum design bending angle of the blade, based on the initial expression and the maximum bending expression; the radius of roller 12 is less than the minimum radius of curvature of the blade trailing edge at different bending angles.

[0041] Step 7: Based on the global Cartesian coordinate system, define the projection point of the suction surface mounting line of the blade in the initial state as point A, and define the projection point of the suction surface mounting line of the blade in the global Cartesian coordinate system at the maximum design bending angle as A'. Set the coordinates of the maximum curvature point on the suction surface of the blade at the maximum design bending angle as the initial coordinates of point A'. Keep the relative chord length position of the suction surface mounting line the same in the initial state and at the maximum design bending angle, and determine the initial coordinates of point A in the initial state of the blade.

[0042] Step 8: Based on the global Cartesian coordinate system, define the projection point of the hinge axis 17 of the second main rod 4 and the suction surface branch rod 7 onto the global Cartesian coordinate system as point D, and the projection point of the axis of the roller 12 onto the global Cartesian coordinate system as point C. Define the projection point of the hinge axis 17 of the second main rod 4 and the suction surface branch rod 7 onto the global Cartesian coordinate system as point D', and the projection point of the axis of the roller 12 onto the global Cartesian coordinate system as point C' when the blade is at its maximum design bending angle. The angle between line segment OD and the x-axis is... The angle between line segment OD' and the x-axis is Based on points C, C', D, D', A, A', line segment OD, line segment CD length, and line segment DA length, and The geometric relationships are used to construct a system of equations to solve for the lengths of line segment OD and DC. and The final solution and the initial solution for the length of line segment DA; the constructed system of equations is as follows: ; ; ; ; ; ; ; ; ; in, for and The difference, Let D be the x-coordinate of point D. Let D be the ordinate of point D. Let D' be the x-coordinate of point D. Let D' be the ordinate of point D. Let A be the x-coordinate of point A. Let A be the ordinate of point A. Let A' be the x-coordinate. Let A' be the ordinate of point A'. Let C be the x-coordinate. Let C be the ordinate of point C. Let C' be the x-coordinate. Let C' be the ordinate of point C. Let O be the straight-line distance between points O and D. Let D be the straight-line distance between points A and D. Let C be the straight-line distance between points C and D; among the above 9 equations, there are a total of , , , , , , , , With a total of 9 variables, satisfying the solution conditions, we can determine the unique linkage mechanism formed by points O, D, A, and C, that is, determine the initial configuration and position of the second main rod 4, the tail edge support rod 10, the suction surface branch rod 7, and the suction surface boss 8. Among them, the configuration of the second main rod 4 and the tail edge support rod 10 has been finally determined.

[0043] The initial configuration and position determined above cannot guarantee that the second main rod 4 and the suction surface branch rod 7 are on a straight line in the initial state of the blade, that is, it cannot guarantee that points O, D and A are collinear; further optimization is needed: Step 9, the final coordinates of point A are determined by maximizing the collinearity of line segments OD and DA through an optimization algorithm. The final coordinates of point A' are determined based on the fact that the relative chord length of the suction surface mounting line is the same in the initial state and at the maximum design bending angle of the blade, combined with the final coordinates of point A. In each iteration, the suction surface mounting line is ensured to be located on the suction surface of the blade, and the relative chord length of the suction surface mounting line is the same in the initial state and at the maximum design bending angle of the blade. In this embodiment, the optimization algorithm is the steepest descent method. The method for determining the final coordinates of points A and A' in this embodiment ensures that the length of the flexible skin 9 from the point where the fixed part of the flexible skin 9 corresponds to the suction surface side of the blade and the moving part meets point A remains the same in the initial state and at the maximum design bending angle of the blade, so that the elastic bending energy of the flexible skin 9 is minimized. In determining the final coordinates of points A and A', the thickness of the flexible skin 9 is ignored. That is, the collinearity of points O, D, and A is based on the fact that point A is considered the coordinate of the projection of the centerline of the suction surface boss 8 onto the global Cartesian coordinate system. This determines the final configuration and position of the second main rod 4, the trailing edge support rod 10, the suction surface branch rod 7, and the suction surface boss 8. Step 10: Based on the global plane rectangular coordinate system, define the projection point of the pressure surface mounting line of the blade in the initial state as point B, and define the projection point of the pressure surface mounting line of the blade in the global plane rectangular coordinate system at the maximum design bending angle as point B'. Set the coordinates of the maximum curvature point on the pressure surface of the blade at the maximum design bending angle as the final coordinates of point B'. Keep the relative chord length position of the pressure surface mounting line of the blade the same in the initial state and at the maximum design bending angle, and determine the final coordinates of point B of the blade in the initial state. Step 11: Based on the global Cartesian coordinate system, define point E as the projection point of the hinge axis 17 of the first main rod 5 and the pressure surface branch rod 14 on the global Cartesian coordinate system in the initial state of the blade. Define point E' as the projection point of the hinge axis 17 of the first main rod 5 and the pressure surface branch rod 14 on the global Cartesian coordinate system when the blade is at its maximum design bending angle. The angle between line segment OE and the x-axis is... The angle between line segment OE' and the x-axis is The determination is based on the fact that line segments OE' and E'B' are collinear when the blade is at its maximum design bending angle. ,according to reduce The value is determined by the blade at the maximum design bending angle. .

[0044] Step 12, based on points E, E', B, B', line segment OE, and line segment EB, and The geometric relationships are used to construct a system of equations to solve for the final lengths of line segments OE and EB. The system of equations constructed is as follows: ; ; ; ; ; ; in, Let E be the x-coordinate. Let E be the ordinate of point E. Let E' be the x-coordinate of point E'. Let E' be the ordinate of point E'. Let B be the x-coordinate. Let B be the ordinate of point B. Let B' be the x-coordinate. Let B' be the ordinate of point B. The straight-line distance between points O and E is... Let E be the straight-line distance between points E and B; among the above 6 equations, there are a total of , , , , , There are a total of 6 variables that satisfy the solution conditions, namely, determining the configuration and position of the first main rod 5, the pressure surface branch rod 14, and the pressure surface boss 13.

[0045] In this embodiment, the trailing edge support 10 is preset to be the line segment AC between points A and C. After the calculation is completed, if there is some interference between the line segment AC and point E, the middle position of the trailing edge support 10 can be bent towards the suction surface of the blade to form a trailing edge support 10 with a bend. The projection of the bending position of the trailing edge support 10 on the global plane rectangular coordinate system is point F, forming the bent line segment AFC. The selection of point F should ensure that it does not interfere with other connecting rods of the skeleton assembly, and at the same time, it is always inside the flexible skin 9.

[0046] The skeleton components determined by the above method can ensure the second-order continuity of the blade profile curvature during the blade adjustment process. The deformation of the flexible skin 9 can be considered to follow the bending theory of elastic thin plates. According to the Euler-Bernoulli beam equation, the curvature of the flexible skin 9 is... The relationship with bending moment is: ; in, The deflection of the flexible skin 9, The bending moment distribution applied to the flexible skin 9 by the skeleton components. This refers to the bending stiffness of the flexible skin 9. Since the skeleton assembly acts on the flexible skin 9 through the pressure surface boss 13, the suction surface boss 8, and the roller 12, these forces are physically distributed, and it can be known that… The stiffness varies smoothly across the entire chord length of the blade. Furthermore, due to the uniform material and thickness of the flexible skin 9, its bending stiffness is... It is a constant or a smooth variable. Therefore, it can be known that the curvature of the flexible skin is continuous throughout the entire range, and the blade profile always maintains second-order continuity of curvature during deformation.

[0047] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A flexible, adjustable blade adaptable to a wide range of operating conditions, characterized in that, include: Fixed section (1), pivot (3), skeleton assembly, roller (12) and flexible skin (9); The fixed section (1) corresponds to the part of the blade near the leading edge of the blade. The rotating shaft (3) is parallel to the blade height direction. The rotating shaft (3) is rotatably mounted on the side of the fixed section (1) facing away from the leading edge of the blade. The skeleton assembly and the rotating shaft (3) are fixedly connected, and the skeleton assembly extends from the fixed section (1) towards the trailing edge of the blade. The axis of the roller (12) is parallel to that of the rotating shaft (3). The roller (12) is rotatably mounted at one end of the skeleton assembly near the trailing edge of the blade. The flexible skin (9) wraps around the fixed section (1), the skeleton assembly, and the... The flexible skin (9) on the outer periphery of the roller (12) is fixed to the surface of the fixed section (1) as a fixed part. The flexible skin (9) on the outer periphery of the roller (12) is movable. The outer surface of the flexible skin (9) forms the aerodynamic profile of the blade. The end of the fixed section (1) facing away from the rotating shaft (3) supports the flexible skin (9) to define the leading edge profile of the blade. The circumferential side of the roller (12) facing away from the frame assembly is attached to and supports the flexible skin (9) to define the trailing edge profile of the blade. The flexible skin (9) attached to the side of the fixed section (1) corresponding to the pressure surface of the blade forms the pressure surface profile of the fixed part, and the flexible skin (9) attached to the side of the fixed section (1) corresponding to the suction surface of the blade forms the suction surface profile of the fixed part. The skeleton assembly is partially movably connected to the flexible skin (9) corresponding to the blade pressure surface to define the pressure surface profile of the movable part; the skeleton assembly is partially movably connected to the flexible skin (9) corresponding to the blade suction surface to define the suction surface profile of the movable part. The skeleton assembly is configured such that when the rotating shaft (3) is externally driven to rotate around the axis of the rotating shaft (3), the skeleton assembly rotates with the rotating shaft (3) around the axis of the rotating shaft (3), thereby driving the movable part to rotate around the axis of the rotating shaft (3) to adjust the bending angle of the blade.

2. The wide-condition adaptable flexible adjustable blade according to claim 1, characterized in that, The skeleton component includes: The first main rod (5) and the second main rod (4) are fixedly connected at one end to the rotating shaft (3), and the other end of the first main rod (5) extends toward the blade pressure surface and the other end of the second main rod (4) extends toward the blade suction surface. The pressure surface branch rod (14) is hinged to the end of the first main rod (5) away from the rotating shaft (3); The pressure surface boss (13) is fixed on the inner wall of the pressure surface of the blade corresponding to the movable part, and the end of the pressure surface branch rod (14) away from the first main rod (5) is hinged to the pressure surface boss (13). The suction surface branch rod (7) is hinged to the end of the second main rod (4) away from the pivot (3); The suction surface boss (8) is fixed on the inner wall of the suction surface of the blade corresponding to the movable part. The end of the suction surface branch rod (7) away from the second main rod (4) is hinged to the suction surface boss (8). The trailing edge support rod (10) is fixedly connected to the end of the second main rod (4) away from the rotating shaft (3). The end of the trailing edge support rod (10) away from the second main rod (4) extends to the trailing edge of the blade. The roller (12) is rotatably mounted on the trailing edge support rod (10). Among them, the hinge shaft (17) and the rotating shaft (3) at both ends of the pressure surface branch rod (14) and the suction surface branch rod (7) are parallel, and the pressure surface boss (13) is closer to the blade trailing edge than the suction surface boss (8).

3. The wide-condition adaptable flexible adjustable blade according to claim 2, characterized in that, A pressure surface stop (11) is provided at the end of the first main rod (5) that is hinged to the pressure surface branch rod (14). The pressure surface stop (11) is located on the side of the pressure surface branch rod (14) facing the blade suction surface. When the blade is bent to the maximum designed bending angle, the first main rod (5) and the pressure surface branch rod (14) are on a straight line, and the pressure surface branch rod (14) abuts against the pressure surface stop (11), restricting the pressure surface branch rod (14) from rotating to the side of the first main rod (5) facing the blade suction surface.

4. The wide-condition adaptable flexible adjustable blade according to claim 3, characterized in that, The second main rod (4) is provided with a suction surface stop (6) at the end that is hinged to the suction surface branch rod (7). The suction surface stop (6) is located on the side of the suction surface branch rod (7) facing the blade pressure surface. When the blade is in the initial state, the second main rod (4) and the suction surface branch rod (7) are on a straight line, and the suction surface branch rod (7) abuts against the suction surface stop (6), restricting the suction surface branch rod (7) from rotating to the side of the second main rod (4) facing the blade pressure surface.

5. The wide-condition adaptable flexible adjustable blade according to claim 1, characterized in that, The axis of the rotating shaft (3) is located at the center of the blade thickness direction relative to the chord length position of the rotating shaft (3).

6. The wide-condition adaptable flexible adjustable blade according to claim 1, characterized in that, The relative chord length position of the end face of the fixed segment (1) facing away from the leading edge of the blade coincides with the relative chord length position corresponding to the maximum thickness position of the blade in its initial state.

7. The wide-condition adaptable flexible adjustable blade according to claim 2, characterized in that, The suction surface protrusion (8) is an elongated strip extending along the axial direction of the rotating shaft (3). The center position of the suction surface protrusion (8) in the width direction corresponds to the point of maximum curvature on the suction surface of the blade when the blade is at the maximum designed bending angle.

8. The wide-condition adaptable flexible adjustable blade according to claim 2, characterized in that, The pressure surface boss (13) is an elongated strip extending along the axial direction of the rotating shaft (3). The center position of the pressure surface boss (13) in the width direction corresponds to the point of maximum curvature on the pressure surface of the blade when the blade is at the maximum design bending angle.

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