Front edge and gravity center sweep angle decoupling rotating vane design method for improving efficiency and margin

Abstract

The invention discloses a front edge and gravity center sweep angle decoupling rotating vane design method for improving efficiency and margin. The rotating vane design method comprises the steps that a first control position and a second control position which are located between a vane tip and a vane root of a rotating vane and are spaced from each other are arranged in the height extension direction of the rotating vane; a leading edge line between the first control position and the second control position on the rotating vane is adjusted to sweepback. Therefore, as the front edge line of the rotating vane between the first control position and the second control position is swept back, the shock wave three-dimensional structure is changed, the shock wave intensity under ultrasonic incoming flow is reduced, the shock wave loss is reduced, meanwhile, the interference loss between the shock wave and a boundary layer is reduced, the flow loss is further reduced, and the efficiency of the rotating vane is improved.

Description

Technical Field

[0001] This article relates to the field of aero propulsion technology, and particularly to a decoupled rotor blade design method for the leading edge and center of gravity sweep angles to improve efficiency and margin. Background Art

[0002] With the continuous improvement of the performance requirements of aero engines, the design trend of compression components gradually develops towards higher stage pressure ratios. In the early stage, designers increased the stage pressure ratio by increasing the diffusion factor, but this method was ultimately limited by the aerodynamic efficiency. Subsequently, the industry tried to achieve higher pressure ratios by increasing the rotational speed. However, the increase in rotational speed brought constraints on structural strength and gradually formed a bottleneck. The current design trend is more inclined to adopt wide-chord blade designs to increase the stage pressure ratio at a limited rotational speed, but this design path brings problems such as an increase in axial size and structural lightweighting, and further exacerbates the aeroelastic problems.

[0003] For fan / compressor rotor blades with a high load per unit axial length, the application of swept blades is becoming increasingly crucial because they have significant advantages in the comprehensive optimization of aerodynamic performance, aeroelastic stability, and structural performance. The introduction of this design concept provides a new direction for the further development of aero engine compression components. In recent years, a large number of studies have shown that the application of compound sweep designs in high-load fan / compressor rotor blades can achieve aerodynamic performance benefits such as reducing shock losses, increasing efficiency, and margin. However, in the engineering application stage, it is impossible to ignore constraints such as blade flutter and structural strength and blindly pursue aerodynamic performance, which will pose more stringent requirements for swept designs. How to introduce the consideration of constraints at the beginning of blade aerodynamic design is an urgent problem to be solved for the mature application of swept blades. Summary of the Invention

[0004] The technical problem to be solved by this application is how to improve the efficiency of the rotor blade.

[0005] The embodiments of this application provide a decoupled rotor blade design method for the leading edge and center of gravity sweep angles to improve efficiency and margin, which includes:

[0006] Set first and second control positions that are spaced apart from each other between the tip and root of the rotor blade in the spanwise direction of the rotor blade;

[0007] Adjust the leading edge line between the first and second control positions on the rotor blade to be swept backward.

[0008] In a schematic embodiment, the first control position is the position where the relative inlet Mach number of the rotor blade is 1, and the second control position is the shock position of the B2B section of the rotor blade.

[0009] In a schematic embodiment, the second control position is located in the region between 70% and 80% of the span of the rotor blade.

[0010] In a schematic embodiment, it further includes:

[0011] A third control position is set in the spanwise direction of the rotor blade, and the third control position is located at the non-swept position of the center of gravity of the rotor blade;

[0012] The center of gravity line between the third control position and the tip of the rotor blade is adjusted to be forward-swept.

[0013] In a schematic embodiment, the third control position is located in the region between 50% and 100% of the span of the rotor blade.

[0014] In a schematic embodiment, it further includes:

[0015] The leading edge line between the third control position and the tip of the rotor blade is adjusted to be rearward-swept.

[0016] In a schematic embodiment, by setting the leading edge sweep angle between the first control position and the second control position on the rotor blade to a positive value, the leading edge line between the first control position and the second control position on the rotor blade is adjusted to be rearward-swept;

[0017] The leading edge sweep angle at the tip is set to -20° to 30°, and the leading edge sweep angle of the rotor blade varies smoothly along the span of the rotor blade.

[0018] By setting the center of gravity sweep angle between the third control position and the tip of the rotor blade to a negative value, the center of gravity line between the third control position and the tip of the rotor blade is adjusted to be forward-swept;

[0019] The center of gravity sweep angle at the tip is set to -10° to 0°, and the center of gravity sweep angle of the rotor blade varies smoothly along the span of the rotor blade.

[0020] In a schematic embodiment, by adjusting the circumferential and axial offsets of the elemental airfoil, the leading edge sweep angle and the center of gravity sweep angle are changed in the same direction, and by adjusting the chordwise position of the maximum thickness of the elemental airfoil, the leading edge sweep angle and the center of gravity sweep angle are changed in the opposite direction, until the leading edge sweep angle between the first control position and the second control position on the rotor blade is set to a positive value, the leading edge sweep angle at the tip is set to -20° to 30°, the center of gravity sweep angle between the third control position and the tip of the rotor blade is set to a negative value, the center of gravity sweep angle at the tip is set to -10° to 0°, the leading edge sweep angle of the rotor blade varies smoothly along the span of the rotor blade, and the center of gravity sweep angle of the rotor blade varies smoothly along the span of the rotor blade.

[0021] In a schematic embodiment, based on the fact that there is a leading edge sweep angle less than -20 degrees on the rotor blade, the leading edge line meridian projection is adjusted to adjust the rotor blade to a preset swept shape.

[0022] In a schematic embodiment, the preset swept shape is that the leading edge line is rearward-swept and the center of gravity line is forward-swept.

[0023] In the technical solution of the present application, since the leading edge line of the rotor blade sweeps back between the first control position and the second control position, the three-dimensional structure of the shock wave is changed, the shock wave intensity under supersonic incoming flow is reduced, the shock wave loss is decreased, and at the same time, the interference loss between the shock wave and the boundary layer is reduced, further reducing the flow loss and improving the efficiency of the rotor blade.

[0024] Other features and advantages of the present application will be described in the subsequent specification, and in part will become apparent from the specification, or will be understood by implementing the present application. Other advantages of the present application can be realized and obtained through the solutions described in the specification and the drawings. Description of the Drawings

[0025] The drawings are used to provide an understanding of the technical solution of the present application, and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation to the technical solution of the present application.

[0026] Figure 1 It is a schematic diagram of the sweep angle distribution in the embodiment of the present application;

[0027] Figure 2 It is a schematic diagram of the rotor blade in the meridian direction in the embodiment of the present application;

[0028] Figure 3 It is a schematic diagram of the rotor blade in the direction perpendicular to the meridian in the embodiment of the present application;

[0029] Figure 4 It is a three-dimensional schematic diagram of the rotor blade in the embodiment of the present application;

[0030] Figure 5 It is a schematic diagram of the rotation direction of the rotor blade in the embodiment of the present application;

[0031] Figure 6 It is a schematic diagram of the sweep angle distribution of a rotor blade in the embodiment of the present application;

[0032] Figure 7 It is a three-dimensional schematic diagram of the rotor blade and the hub in the embodiment of the present application;

[0033] Figure 8 It is a schematic diagram of the stress distribution on the pressure side and suction side of the rotor blade in the embodiment of the present application;

[0034] Figure 9 It is a schematic diagram of the characteristic curve of the rotor blade in the embodiment of the present application;

[0035] Figure 10 It is a schematic diagram for comparing different leading edge sweep angle schemes while keeping the tip center of gravity sweep angle of a certain type unchanged. Detailed Embodiments

[0036] This application describes multiple embodiments, but the description is exemplary rather than restrictive, and it will be apparent to those of ordinary skill in the art that there can be more embodiments and implementation solutions within the scope of the embodiments described in this application. Although many possible combinations of features are shown in the drawings and discussed in the detailed description, many other combinations of the disclosed features are also possible. Unless specifically restricted, any feature or element of any embodiment can be combined with any other feature or element in any other embodiment, or can replace any other feature or element in any other embodiment.

[0037] This application includes and contemplates combinations with features and elements known to those of ordinary skill in the art. The embodiments, features, and elements disclosed in this application can also be combined with any conventional features or elements to form a unique inventive solution. Any feature or element of any embodiment can also be combined with features or elements from other inventive solutions to form another unique inventive solution. Therefore, it should be understood that any feature shown and / or discussed in this application can be implemented alone or in any suitable combination. Therefore, the embodiments are not subject to other limitations except those made in accordance with the appended claims and their equivalents. In addition, various modifications and changes can be made within the scope of the appended claims.

[0038] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not depend on the specific order of the steps described herein, the method or process should not be limited to the specific order of steps described. As will be understood by those of ordinary skill in the art, other step orders are possible. Therefore, the specific order of steps set forth in the specification should not be construed as a limitation on the claims. In addition, the claims directed to the method and / or process should not be limited to performing their steps in the order written, and those skilled in the art can easily understand that these orders can be varied and still remain within the spirit and scope of the embodiments of this application.

[0039] This embodiment proposes a decoupled rotor blade design method for the leading edge and the center of gravity sweep angle to improve efficiency and margin. The rotor blade design method includes the following steps:

[0040] Step S1: Set a first control position and a second control position that are spaced apart from each other between the tip and the root of the rotor blade in the spanwise direction of the rotor blade.

[0041] The rotating blade is a blade disposed on the hub. The rotating blade can rotate following the rotation of the hub. The rotating blade is provided with a blade tip and a blade root, and the blade tip and the blade root are located at opposite ends of the rotating blade. The blade root is the end where the rotating blade is connected to the hub, and the blade tip is the end of the rotating blade close to the casing. The spanwise direction of the rotating blade is the direction from the blade root of the rotating blade to the blade tip of the rotating blade. As Figure 1 shown, in the spanwise direction of the rotating blade, the distance from the first control position on the rotating blade to the blade root is L1, and the distance from the second control position to the blade root is L2.

[0042] The blade profile of the rotating blade can be designed in advance by using the stacking method of elementary blade profiles. The stacking method of elementary blade profiles is a method of combining a series of elementary blade profiles in a certain way to form a complete blade.

[0043] Step S2: Adjust the leading edge line between the first control position and the second control position on the rotating blade to be swept back.

[0044] The rotating blade includes a leading edge and a back edge. The leading edge is the edge where the airflow in the rotating blade first contacts. The leading edge line is the contour line that divides the most front-end part of the contact between the rotating blade and the oncoming gas, and the curve formed by the edge of the rotating blade where the airflow first contacts is the leading edge line. The leading edge line extends from the blade root to the blade tip. The back edge is located at the other edge of the rotating blade opposite to the leading edge.

[0045] When the leading edge line between the first control position and the second control position of the rotating blade is swept back, when the airflow passes through this area, the airflow will be decomposed into a component perpendicular to the leading edge and a component parallel to the leading edge. The perpendicular component produces effects such as lift, and the parallel component does not produce lift. Due to the effect of sweepback, the airflow velocity component perpendicular to the leading edge is relatively reduced, and a shock wave will only appear at a higher rotational speed, thus delaying the generation of the shock wave.

[0046] Therefore, the leading edge line between the first control position and the second control position of the rotating blade is swept back, changing the three-dimensional structure of the shock wave, reducing the shock wave intensity under supersonic oncoming flow, reducing the shock wave loss, and at the same time reducing the interference loss between the shock wave and the boundary layer, further reducing the flow loss and improving the efficiency of the rotating blade.

[0047] In a schematic embodiment, the first control position is the position where the relative Mach number at the inlet of the rotating blade is 1, and the second control position is the shock wave position at the B2B section of the rotating blade;

[0048] The B2B cross-section refers to the cross-section at a specific position in the direction from the blade tip to the blade root. On the B2B cross-section, a shock wave may first form near the leading edge of the rotating blade. Since the airflow is suddenly blocked by the rotating blade at the leading edge, parameters such as the airflow velocity and pressure will change sharply, making it easy to generate a shock wave. The position of the B2B cross-section shock wave refers to the cross-section position on the rotating blade where the shock wave is generated in the direction from the blade tip to the blade root. The factors affecting the position of the B2B cross-section shock wave include the incoming flow Mach number, the airflow attack angle, the geometric parameters of the blade, and the operating speed of the turbine, etc.

[0049] For the rotating blade of the fan / compressor to be designed, numerical simulation or tests can be carried out to obtain the flow field structure. According to the obtained flow field structure, the position where the relative inlet Mach number on the rotating blade is 1 and the position of the B2B cross-section shock wave under the design conditions can be determined.

[0050] In a schematic embodiment, the second control position is located in the region between 70% and 80% of the blade height of the rotating blade.

[0051] The blade height of the rotating blade refers to the distance from the blade root to the blade tip. The second control position being located in the region between 70% and 80% of the blade height of the rotating blade means that the second control position is located in the region starting from the blade root and greater than 70% of the blade height and less than 80% of the blade height.

[0052] In a schematic embodiment, step S1 further includes: setting a third control position in the blade height direction of the rotating blade, and the third control position is located at the position where the center of gravity of the rotating blade has no sweep.

[0053] The position where the center of gravity has no sweep is the position where the sweep angle of the center of gravity on the center of gravity line of the rotating blade is zero. For the rotating blade of the fan / compressor to be designed, numerical simulation or tests can be carried out to obtain the flow field structure. According to the obtained flow field structure, the position where the center of gravity of the rotating blade has no sweep under the design conditions can be determined. As Figure 1 shown, in the blade span direction of the rotating blade, the distance from the third control position on the rotating blade to the blade root is T1.

[0054] Step S2 further includes: adjusting the center of gravity line between the third control position and the blade tip on the rotating blade to be forward-swept.

[0055] The center of gravity line is the connection line of the geometric centers of gravity of all the elementary blade profiles that make up the rotating blade. The center of gravity line extends from the blade root to the blade tip.

[0056] Adjusting the center of gravity line between the third control position and the blade tip on the rotating blade to be forward-swept moves the normal shock wave in the "one oblique and one normal" shock wave system formed by the higher Mach number incoming flow at the blade tip backward, improving the stall margin at the blade tip.

[0057] In a schematic embodiment, the third control position is located in the region between 50% and 100% of the blade height of the rotating blade.

[0058] The third control position is located in the region between 50% and 100% of the blade height, which means the third control position is located in the region starting from the blade root and greater than 50% of the blade height and less than 100% of the blade height. That is, the distance from the third control position to the blade tip is less than the distance from the third control position to the blade root.

[0059] In a schematic embodiment, step S2 further includes: adjusting the leading edge line between the third control position and the blade tip on the rotor blade to be swept back.

[0060] The center of gravity line between the third control position and the blade tip on the rotor blade is adjusted to be swept forward, the leading edge line between the third control position and the blade tip on the rotor blade is adjusted to be swept back, the part of the center of gravity line and the leading edge line between the third control position and the blade tip on the rotor blade has a reverse sweep profile, and the rotor blade has smaller radial deformation and torsional deformation, which can further enhance its aerodynamic stability on the premise of ensuring the structural strength of the rotor blade.

[0061] In a schematic embodiment, in step S2, by setting the leading edge sweep angle between the first control position and the second control position on the rotor blade to a positive value, the leading edge line between the first control position and the second control position on the rotor blade is adjusted to be swept back;

[0062] The leading edge sweep angle at the blade tip is set to -20° to 30°, and the leading edge sweep angle of the rotor blade varies smoothly along the spanwise direction of the rotor blade.

[0063] In this way, the leading edge line where the leading edge sweep angle is set to a negative value is swept forward, and the leading edge line where the leading edge sweep angle is set to a positive value is swept back. By adjusting the change of the leading edge sweep angle on the rotor blade, the method of making the leading edge line between the first control position and the second control position swept back is simple and easy to implement. The smoothly varying leading edge sweep angle can make the air flow flow more smoothly over the surface of the rotor blade, reduce the possibility of air flow separation, and thus reduce the flow loss. The smoothly varying leading edge sweep angle of the rotor blade can also make the air flow force more uniform, reduce the excitation force generated by air flow instability, avoid fatigue damage of the rotor blade, and improve the reliability and stability of the rotor blade. At the same time, it can also guide the air flow to flow more evenly over the rotor blade, avoid the situation of too high or too low flow velocity locally, make the air flow in the impeller channel more uniform, improve the work efficiency, and make the energy conversion more sufficient.

[0064] In this embodiment, as Figures 2 to 5 shown, the calculation formula of the center of gravity sweep angle is as follows:

[0065]

[0066] The air flow velocity vector at the leading edge or the given geometric reference direction vector;

[0067] η: Projection angle in the r-θ plane with respect to the radial direction. It is positive when, as a point moves along the centroid line W from the blade root towards the blade tip, both r and θ increase.

[0068] μ: Projection angle in the x-r plane with respect to the radial direction. It is positive when, as a point moves along the centroid line W from the blade root towards the blade tip, both r and x increase.

[0069] Slope angle of the meridional projection of the stream surface at point P on the centroid line W.

[0070] β: Angle between the projection in the x-θ plane and the axial direction. The θ component is positive in the positive θ direction.

[0071] λ: Centroid sweep angle. With Intersection angle. If The intersection of the positive direction with the positive x direction forms an acute angle, it is positive.

[0072] v: Dihedral angle. If the plane Ω B The positive θ plane and Ω S The front plane intersect at an acute angle, it is positive. 90 - v is the angle between the plane Ω B And the axisymmetric plane Ω S Intersection angle.

[0073] Ω S : Rotating stream surface.

[0074] Ω B : The plane formed by the tangent at point P on the centroid line W and the given (velocity) direction vector.

[0075] Ω L : Unit vector And the unit vector θ form a plane.

[0076] x, r, θ: Global cylindrical coordinates. x is the axial direction of the hub, r is the radial direction of the hub, θ is the circumferential direction of the hub, and the hub rotation direction is positive.

[0077] Unit vectors in the directions of the global cylindrical coordinates.

[0078] Unit vectors of the local coordinate system. Are in the same direction as the given (velocity) direction vector. In the plane Ω B Inside and Perpendicular to Then perpendicular to And

[0079] Unit vectors in the local coordinate system At Ω B At the point P inside, along the tangential direction of the centroid line W At Ω L In the plane Perpendicular to in the right - hand rule And

[0080] In a schematic embodiment, in step S2, the centroid sweep angle between the third control position and the tip on the rotor blade is set to a negative value to adjust the centroid line between the third control position and the tip on the rotor blade to be forward - swept;

[0081] The centroid sweep angle at the tip is set to - 10° to 0°, and the centroid sweep angle of the rotor blade varies smoothly along the span of the rotor blade.

[0082] In this way, the centroid line is forward - swept where the centroid sweep angle is set to a negative value, and the centroid line is backward - swept where the centroid sweep angle is set to a positive value. The method of making the centroid line between the third control position and the tip forward - swept by adjusting the change of the centroid sweep angle on the rotor blade is simple and easy to implement. The smooth centroid sweep angle of the rotor blade helps to optimize the energy exchange process between the fluid and the rotor blade, making the energy loss smaller when the fluid pushes the rotor blade to rotate or is compressed by the rotor blade, thereby improving the overall energy conversion efficiency of the device. The smooth centroid sweep angle can make the load distributions such as centrifugal force and aerodynamic force on the rotor blade during rotation more uniform. It avoids the situation of excessive local stress caused by sudden change of the centroid sweep angle, reduces the risk of fatigue cracks and fractures of the rotor blade, and prolongs the service life of the rotor blade. The smooth centroid sweep angle can make the deformation of each part of the rotor blade structure more coordinated when bearing external forces. It improves the overall anti - deformation ability of the rotor blade, ensures that the rotor blade can still maintain good shape and dimensional accuracy under complex working conditions, and maintains the normal operation of the device.

[0083] In this embodiment, as Figures 2 to 5 shown, the calculation formula of the centroid sweep angle is as follows:

[0084]

[0085] Airflow velocity vector or given geometric reference direction vector;

[0086] η: The angle between the projection in the r - θ plane and the radial direction, which is positive when r increases and θ also increases as a point moves along the centroid line W from the root to the tip of the blade;

[0087] μ: The angle between the projection in the x - r plane and the radial direction, which is positive when r increases and x also increases as a point moves along the centroid line W from the root to the tip of the blade;

[0088] The slope angle of the streamline meridian projection at point P on the center of gravity line W;

[0089] β: The angle between the projection in the x-θ plane and the axial direction, The θ component is positive in the positive θ direction;

[0090] λ: The center of gravity grazing angle, With The included angle. If The included angle between the positive direction and the positive x direction is positive when it is an acute angle;

[0091] ν: The dihedral angle. If the plane Ω B The positive θ plane and Ω S The positive face intersection is positive when it is an acute angle. 90 - ν is the included angle between the plane Ω B And the axisymmetric plane Ω S The included angle;

[0092] Ω S : The rotating streamline surface;

[0093] Ω B : The plane formed by the tangent line at point P on the center of gravity line W and the given (velocity) direction vector;

[0094] Ω L : The unit vector And the unit vector θ form the plane;

[0095] x, r, θ: Global cylindrical coordinates. x is the axial direction of the hub, r is the radial direction of the hub, θ is the circumferential direction of the hub, and the hub rotation direction is positive;

[0096] Unit vectors in each direction of the global cylindrical coordinates;

[0097] Unit vectors in the local coordinate system, In the same direction as the given (velocity) direction vector, In the plane Ω B Inside and Perpendicular to Then perpendicular to And

[0098] Unit vectors in the local coordinate system, At point P in Ω B Along the tangential direction of the center of gravity line W, In Ω L Plane, Perpendicular to And

[0099] In a schematic embodiment, in step S2, by adjusting the circumferential and axial offsets of the elemental airfoil, the leading-edge sweep angle and the center-of-gravity sweep angle are changed in the same direction, and by adjusting the chordwise position of the maximum thickness of the elemental airfoil, the leading-edge sweep angle and the center-of-gravity sweep angle are changed in the opposite direction, until the leading-edge sweep angle between the first control position and the second control position on the rotating blade is set to a positive value, the leading-edge sweep angle at the blade tip is set to -20° to 30°, the center-of-gravity sweep angle between the third control position and the blade tip on the rotating blade is set to a negative value, the center-of-gravity sweep angle at the blade tip is set to -10° to 0°, the leading-edge sweep angle of the rotating blade varies smoothly along the span of the rotating blade, and the center-of-gravity sweep angle of the rotating blade varies smoothly along the span of the rotating blade.

[0100] By adjusting the circumferential and axial offsets of the elemental airfoil, the leading-edge sweep angle and the center-of-gravity sweep angle corresponding to the elemental airfoil can be increased or decreased simultaneously, and by adjusting the chordwise position of the maximum thickness of the elemental airfoil, one of the leading-edge sweep angle and the center-of-gravity sweep angle corresponding to the element can be increased, and the other of the leading-edge sweep angle and the center-of-gravity sweep angle corresponding to the element can be decreased.

[0101] In this embodiment, step S2 includes the following steps:

[0102] Step S21: By adjusting the circumferential and axial offsets of the elemental airfoil, the leading-edge sweep angle and the center-of-gravity sweep angle are changed in the same direction, and by adjusting the chordwise position of the maximum thickness of the elemental airfoil, the leading-edge sweep angle and the center-of-gravity sweep angle are changed in the opposite direction;

[0103] Step S22: Check whether the leading-edge sweep angle distribution curve satisfies the following conditions: the leading-edge sweep angle between the first control position and the second control position on the rotating blade is set to a positive value, the leading-edge sweep angle at the blade tip is set to -20° to 30°, and the leading-edge sweep angle of the rotating blade varies smoothly along the span of the rotating blade;

[0104] Check whether the center-of-gravity sweep angle distribution curve satisfies the following conditions: the center-of-gravity sweep angle between the third control position and the blade tip on the rotating blade is set to a negative value, the center-of-gravity sweep angle at the blade tip is set to -10° to 0°, and the center-of-gravity sweep angle of the rotating blade varies smoothly along the span of the rotating blade;

[0105] If any of the above conditions is not satisfied, re-enter step S21.

[0106] In a schematic embodiment, the rotating blade design method further includes step S3 after step S2. In step S22, if all conditions are satisfied simultaneously, enter step S3.

[0107] Step S3: Determine whether there is a leading-edge sweep angle less than -20 degrees on the rotating blade. If so, adjust the meridional projection of the leading edge to adjust the rotating blade to a preset swept shape.

[0108] This can avoid the excessive circumferential stacking amount of the rotating blade from affecting the blade profile.

[0109] In summary, in this embodiment, the offset of the elemental blade profile is essentially the axial and circumferential offsets of the centroid of the elemental blade profile, that is, the offset of the centroid stacking line. The leading edge and centroid sweep angle distributions can reach the optimal results by adjusting the circumferential and axial offset amounts of the centroid stacking line in the embodiment, as well as the chordwise positions of the maximum thicknesses of the blade profiles at different spans. The three-dimensional geometric schematic diagram of the rotating blade with the parameters in Figure 6 is as shown in Figure 7 . Again, as shown in Figure 8 , the stress distribution schematic diagram of the suction surface / pressure surface of the rotating blade in the optimal embodiment can be obtained. Specifically, the characteristic line schematic diagram of the optimal example of the present invention, as shown in Figure 9 , selects the load coefficient of 0.4 as the operating point, and nondimensionalizes the pressure, efficiency, and flow rate respectively in the operating point state to obtain the characteristic line from the operating point to the near-stall point.

[0110] Supplementary, Figure 10 compares different leading edge sweep angle schemes that keep the centroid leading edge sweep angle of a type of blade tip unchanged by applying the present invention, as shown in Table 1 below. The performances of rotors with different leading edge sweep angles are compared. Generally speaking, it can be seen that when the leading edge sweep angle increases from -20° to 30°, the margin decreases by 0.35 percentage points, the peak efficiency increases by 0.45 percentage points, and the maximum axial displacement deformation is the smallest when the centroid is in the leading edge sweep and the leading edge is in the trailing edge sweep by 12°.

[0111] Table 1

[0112]

[0113] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0114] In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include at least one of such features.

[0115] In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0116] In the present application, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected to", "fixed", etc. shall be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0117] In the present application, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature can be that the first and second features are in direct contact, or the first feature and the second feature are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or merely means that the first feature is at a higher horizontal level than the second feature. The first feature being "under", "beneath" and "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or merely means that the first feature is at a lower horizontal level than the second feature.

[0118] In the description of this specification, the description with reference to terms such as "an embodiment", "some embodiments", "examples", "specific examples" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0119] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present application.

Claims

1. A decoupled rotor blade design method for leading edge and center of gravity sweep angles to improve efficiency and margin, characterized in that, Including: Set a first control position and a second control position which are located between the tip and the root of the rotating blade in the span direction of the rotating blade and are spaced apart from each other; Adjust the leading edge line between the first control position and the second control position on the rotating blade to be swept back.

2. The vane design method according to claim 1, wherein The first control position is the position where the relative Mach number at the inlet of the rotating blade is 1, and the second control position is the shock wave position of the B2B section of the rotating blade.

3. The vane design method according to claim 2, wherein The second control position is located in the region between 70% and 80% of the span of the rotating blade.

4. The method for the swivel vane design according to any one of claims 1 to 3, characterized in that, Also including: Set a third control position in the span direction of the rotating blade, and the third control position is located at the non-swept position of the center of gravity of the rotating blade; Adjust the center of gravity line between the third control position and the tip of the rotating blade to be swept forward.

5. The rotor design method according to claim 4, characterized in that The third control position is located in the region between 50% and 100% of the span of the rotating blade.

6. The vane design method according to claim 4, characterized in that, Also including: Adjust the leading edge line between the third control position and the tip of the rotating blade to be swept back.

7. The vane design method according to claim 4, characterized in that By setting the leading edge sweep angle between the first control position and the second control position on the rotating blade to be a positive value, the leading edge line between the first control position and the second control position on the rotating blade is adjusted to be swept back; The leading edge sweep angle at the tip is set to -20° to 30°, and the leading edge sweep angle of the rotating blade changes smoothly along the span direction of the rotating blade; By setting the center of gravity sweep angle between the third control position and the tip of the rotating blade to be a negative value, the center of gravity line between the third control position and the tip of the rotating blade is adjusted to be swept forward; The center of gravity sweep angle at the tip is set to -10° to 0°, and the center of gravity sweep angle of the rotating blade changes smoothly along the span direction of the rotating blade.

8. The swivel vane design method according to claim 7, characterized in that, By adjusting the circumferential and axial offsets of the elemental airfoil, the leading edge sweep angle and the center of gravity sweep angle change in the same direction, and by adjusting the chordwise position of the maximum thickness of the elemental airfoil, the leading edge sweep angle and the center of gravity sweep angle change in the opposite direction, until the leading edge sweep angle between the first control position and the second control position on the rotating blade is set to a positive value, the leading edge sweep angle at the tip is set to -20° to 30°, the center of gravity sweep angle between the third control position and the tip of the rotating blade is set to a negative value, the center of gravity sweep angle at the tip is set to -10° to 0°, the leading edge sweep angle of the rotating blade changes smoothly along the span direction of the rotating blade, and the center of gravity sweep angle of the rotating blade changes smoothly along the span direction of the rotating blade.

9. The vane design method according to claim 8, wherein Based on the fact that there is a leading edge sweep angle less than -20 degrees on the rotating blade, adjust the meridian projection of the leading edge line to adjust the rotating blade to a preset sweep type.

10. The method for the swivel vane design according to claim 9, characterized in that, The preset sweep type is that the leading edge line is swept back and the center of gravity line is swept forward.

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