Stationary blade sweep and dihedral angle stacking control method for improving end region flow

Abstract

The invention relates to a static blade swept and dihedral angle stacking control method for improving end region flow, which comprises the following steps of: arranging an upper end wall stacking control position and a lower end wall stacking control position in a region between a blade tip and a blade root of a stator blade on the stator blade, the upper end wall stacking control position is closer to the blade tip than the lower end wall stacking control position; according to the method, the blade profile of the stator blade is determined by adopting an element blade profile stacking method, so that the stator blade sweep forwards in the area between the stacking control position of the lower end wall and the blade root and the area between the stacking control position of the upper end wall and the blade tip; the dihedral angle of the suction surface of the hub in the area between the lower end wall stacking control position and the blade root and the dihedral angle of the suction surface of the casing in the area between the upper end wall stacking control position and the blade tip are obtuse angles. According to the stator blade obtained through the method, the total pressure loss of the end area of the stator blade can be reduced by 20% or above.

Description

Technical Field

[0001] This article relates to the field of aviation propulsion technology, and in particular to a method for controlling the sweep of stationary blades and the dihedral angle stacking to improve the end zone flow. Background Art

[0002] The three-dimensional flow separation in the corner area formed by the suction surface and the end wall of the existing axial fan / compressor blade has been identified as its inherent flow characteristic. With the development trend of using higher-load blades to achieve higher single-stage power, the increase in static pressure rise in the blade channel and the increase in the adverse pressure gradient on the suction surface will aggravate the development of flow separation in the corner area and even cause stall in the corner area. In high-load stator blades, the flow in the end area is even worse due to problems such as large bending angles and thick boundary layers of incoming flow. A large number of research results show that complex flow losses in the end area can account for more than 30% of the total compressor losses, and become more and more serious as the load increases.

[0003] The blade stacking technology started from the early days of borrowing the design method of external flow wings, and the first generation of three-dimensional blades stacked in different torsional directions developed into the second generation of three-dimensional blades that continuously improve the fan / compressor load level through the so-called blade bend and swept stacking design to match the spanwise distribution of the elementary load. It has become a necessary design method for designers to suppress boundary layer separation and adjust the shock wave structure to reduce compressor blade losses through blade stacking technology. Although this technology has gradually entered the engineering application stage, there is still no blade stacking method for the stator end area, resulting in the failure to maximize the potential of blade stacking technology to increase compressor load. Summary of the invention

[0004] The technical problem to be solved by the present application is how to reduce the total pressure loss in the end area of ​​the stator blades.

[0005] The embodiment of the present application provides a method for controlling the sweep of stationary blades and the dihedral angle stacking to improve the flow in the end region, which includes:

[0006] An upper end wall stacking control position and a lower end wall stacking control position are set on the stator blade in an area between the tip and the root of the stator blade, wherein the upper end wall stacking control position is closer to the tip than the lower end wall stacking control position;

[0007] The blade profile of the stator blade is determined by the primitive blade profile stacking method, so that the stator blade is swept forward in the area between the lower end wall stacking control position and the blade root and in the area between the upper end wall stacking control position and the blade tip, and the hub suction surface dihedral angle in the area between the lower end wall stacking control position and the blade root and the casing suction surface dihedral angle in the area between the upper end wall stacking control position and the blade tip are both obtuse angles, the hub suction surface dihedral angle is the angle between the suction surface of the stator blade and the outer peripheral surface of the hub, and the casing suction surface dihedral angle is the angle between the suction surface of the stator blade and the inner peripheral surface of the casing.

[0008] In an illustrative embodiment, it also includes:

[0009] The first inlet metal angle of the primitive airfoil in the area between the lower end wall stacking control position and the blade root is reduced to increase the hub suction surface dihedral angle, and the second inlet metal angle of the primitive airfoil in the area between the upper end wall stacking control position and the blade tip is reduced to increase the casing suction surface dihedral angle.

[0010] In an exemplary embodiment, an upper end wall stacking control position and a lower end wall stacking control position are set in an area between a blade tip and a blade root of a stator blade, including:

[0011] Get the boundary layer thickness δ of the lower end wall h and the thickness of the boundary layer on the upper wall δ t ;

[0012] According to the thickness of the lower end wall boundary layer δ h Determine the distance between the lower end wall stacking control position and the blade root, according to the upper end wall boundary layer thickness δ t Determine the distance from the upper endwall stack control location to the blade tip.

[0013] In an exemplary embodiment, the distance L between the end wall stack control position and the blade root is 1 Equal to 2-5 times the thickness of the lower end wall boundary layer δ h , the distance between the upper end wall stacking control position and the blade tip is equal to 2-5 times the upper end wall boundary layer thickness δ t .

[0014] In an illustrative embodiment, the method of determining the blade profile of the stator blade by using the primitive blade profile stacking method includes:

[0015] By controlling the chord-wise stacking of the primitive blade profile, the leading edge sweep angle in the area between the lower end wall stacking control position and the blade root is positive, the leading edge sweep angle in the area between the upper end wall stacking control position and the blade tip is negative, and the leading edge sweep angle changes smoothly in the span direction of the stator blade;

[0016] By controlling the stacking of the elementary blade profile in the vertical chord direction, the hub suction surface dihedral angle in the area between the lower end wall stacking control position and the blade root and the casing suction surface dihedral angle in the area between the upper end wall stacking control position and the blade tip are both obtuse angles.

[0017] In an exemplary embodiment, the leading edge sweep angle in the region between the lower end wall stacking control position and the blade root is greater than or equal to 10°, and the leading edge sweep angle in the region between the upper end wall stacking control position and the blade tip is less than or equal to -10°.

[0018] In an exemplary embodiment, the hub suction surface dihedral angle in the region between the lower end wall stacking control position and the blade root and the casing suction surface dihedral angle in the region between the upper end wall stacking control position and the blade tip are both greater than 95°.

[0019] In an exemplary embodiment, the first inlet metal angle and the second inlet metal angle are 5°-25°.

[0020] In an exemplary embodiment, the first inlet metal angle and the second inlet metal angle vary smoothly in the span direction of the stator blade.

[0021] The stator blades obtained by the above control method have areas near the blade root and the blade tip that are swept forward, thereby changing the load matching in the span direction of the stator blades, reducing the load near the blade root and blade tip of the stator blades, and moving the high load area backward, thereby weakening the angular zone separation and moving the separation starting point backward. At the same time, since the hub suction surface dihedral angle in the area near the blade root and the casing suction surface dihedral angle in the area near the blade tip of the stator blade are both large, the intersection of the end wall of the stator blade and the suction surface boundary layer can be reduced, thereby weakening the angular zone separation. The stator blade 1 obtained by this method can reduce the total pressure loss in its end area by more than 20%.

[0022] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying 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 on the technical solution of the present application.

[0024] Figure 1 This is a schematic front view of a stator blade in an embodiment of the present application;

[0025] Figure 2 This is a schematic diagram of the cross-sectional changes of the end area of ​​a stator blade in an embodiment of the present application;

[0026] Figure 3 This is a three-dimensional schematic diagram of a stator blade in an embodiment of the present application;

[0027] Figure 4 The distribution of the leading edge sweep angle of a stator blade in the span direction in an embodiment of the present application;

[0028] Figure 5 The distribution of the hub dihedral angle of a stator blade in the chord direction in an embodiment of the present application;

[0029] Figure 6 The distribution of the casing dihedral angle of a stator blade in the chord direction in an embodiment of the present application;

[0030] Figure 7 is a schematic diagram of a stator blade in an embodiment of the present application in the meridian direction;

[0031] Figure 8 Schematic diagram of the stator blade in the embodiment of the present application in the vertical meridian direction;

[0032] Fig. 9 It is a three-dimensional schematic diagram of a stator blade in an embodiment of the present application;

[0033] Fig.10 It is a schematic diagram of the rotation direction of the stator blades in the embodiment of the present application. DETAILED DESCRIPTION

[0034] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0035] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application may also be combined with any conventional features or elements to form a unique invention scheme. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme. Therefore, it should be understood that any feature shown and / or discussed in the present application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the attached claims and their equivalents, the embodiments are not subject to other restrictions. In addition, various modifications and changes may be made within the scope of protection of the attached claims.

[0036] 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 rely on the specific order of the steps described herein, the method or process should not be limited to the steps of the specific order described. As will be understood by those of ordinary skill in the art, other sequences of steps are also possible. Therefore, the specific sequence of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to the steps of performing them in the order written, and those skilled in the art can easily understand that these sequences can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0037] In an embodiment of the present application, a method for controlling the sweep of a stationary blade and the dihedral angle stacking for improving the flow in the end zone is provided. The method for controlling the sweep of a stationary blade and the dihedral angle stacking for improving the flow in the end zone comprises the following steps:

[0038] Step S1: Figure 1 As shown, an upper end wall stacking control position 15 and a lower end wall stacking control position 14 are set in the area between the blade tip 12 and the blade root 11 of the stator blade 1, wherein the upper end wall stacking control position 15 is closer to the blade tip 12 than the lower end wall stacking control position 14;

[0039] The stator blade 1 is provided with a blade tip 12 and a blade root 11, and the blade tip 12 and the blade root 11 are opposite ends of the stator blade 1. The blade tip 12 is the end of the stator blade 1 close to the casing, and the blade root 11 is the end of the stator blade 1 close to the hub. The span direction of the stator blade 1 is the direction from the blade root 11 to the blade tip 12. In the span direction of the stator blade 1, the blade root 11, the lower end wall stacking control position 14, the upper end wall stacking control position 15 and the blade tip 12 are arranged in sequence. The upper end wall stacking control position 15 is close to the blade tip 12, and the lower end wall stacking control position 14 is close to the blade root 11.

[0040] Step S2: The blade profile of the stator blade 1 is determined by using the primitive blade profile stacking method, so that the stator blade 1 is swept forward in the area between the lower end wall stacking control position 14 and the blade root 11 and in the area between the upper end wall stacking control position 15 and the blade tip 12, and the hub suction surface dihedral angle in the area between the lower end wall stacking control position 14 and the blade root 11 and the casing suction surface dihedral angle in the area between the upper end wall stacking control position 15 and the blade tip 12 are both obtuse angles.

[0041] The primitive blade shape refers to a representative micro blade shape unit obtained by infinitely subdividing the stator blade 1 along a certain direction (for example, the span direction or chord direction of the stator blade 1). The primitive blade shape can be any known primitive blade shape of the stator blade 1. The primitive blade shape stacking method is a method of combining a series of primitive blade shapes in a certain way to form a complete blade.

[0042] The stator blade 1 includes a leading edge L and a back edge 13. The leading edge L is the edge of the stator blade 1 that the airflow first contacts, and is the starting end of the blade profile curve in the airflow inflow direction. The back edge 13 is located at the other edge of the stator blade 1 opposite to the leading edge L. The forward sweep of the stator blade 1 in the area between the lower end wall stacking control position 14 and the blade root 11 means that the leading edge L of the stator blade 1 in this area is tilted forward, or the stator blade 1 in this area is extended forward. The forward sweep of the stator blade 1 in the area between the upper end wall stacking control position 15 and the blade tip 12 means that the leading edge L of the stator blade 1 in this area is tilted forward, or the stator blade 1 in this area is extended forward.

[0043] The suction surface is a low-pressure area formed on one side of the stator blade 1 when the fluid flows through the stator blade 1. This side is the suction surface. The end wall refers to the wall that defines the boundary of the flow channel, usually including the outer peripheral wall of the impeller hub and the inner peripheral wall of the casing, which constrains and guides the flow of the fluid. The dihedral angle refers to the angle formed by the end wall and the suction surface. From a spatial perspective, it describes the relative position relationship and inclination degree of the end wall and the suction surface in three-dimensional space.

[0044] The hub suction surface dihedral angle is the angle between the suction surface of the stator blade 1 and the outer peripheral surface of the hub, and the casing suction surface dihedral angle is the angle between the suction surface of the stator blade 1 and the inner peripheral surface of the casing.

[0045] In the embodiment of the present application, the stator blade 1 obtained by the above control method has a forward sweep in the area near the blade root 11 and the area near the blade tip 12, so that the load matching in the span direction of the stator blade 1 can be changed, so that the load near the blade root 11 and the blade tip 12 of the stator blade 1 is reduced, and the high load area is moved backward, so that the angular zone separation is weakened and the separation starting point is moved backward. At the same time, because the hub suction surface dihedral angle of the area near the blade root 11 of the stator blade 1 and the casing suction surface dihedral angle of the area near the blade tip 12 are both large, the intersection of the end wall of the stator blade 1 and the suction surface boundary layer can be reduced, thereby weakening the angular zone separation. The stator blade 1 obtained by this method can reduce the total pressure loss of its end area by more than 20%.

[0046] In an illustrative embodiment, step S3 is further included after step S2.

[0047] Step S3: Figure 2 As shown, the first inlet metal angle of the primitive airfoil in the area between the lower end wall stacking control position 14 and the blade root 11 is reduced to increase the hub suction surface dihedral angle in the area between the lower end wall stacking control position 14 and the blade root 11, and the second inlet metal angle of the primitive airfoil in the area between the upper end wall stacking control position 15 and the blade tip 12 is reduced to increase the casing suction surface dihedral angle in the area between the upper end wall stacking control position 15 and the blade tip 12.

[0048] The inlet metal angle is the angle between the mid-arc line of the stator blade and the axial direction of the hub. The axial direction of the hub in this application refers to the axial direction of the hub at the position of the stator blade. The first inlet metal angle and the second inlet metal angle vary smoothly in the span direction of the stator blade 1. The dihedral angle of the hub suction surface in the area between the lower end wall stacking control position 14 and the blade root 11 and the dihedral angle of the casing suction surface in the area between the upper end wall stacking control position 15 and the blade tip 12 vary smoothly in the chord direction.

[0049] In this way, by reducing the first inlet metal angle of the area near the blade root 11 and the second inlet metal angle of the area near the blade tip 12 on the stator blade 1, the screws further increase the angles of the hub suction surface dihedral angle and the casing suction surface dihedral angle, which can further reduce the intersection of the end wall of the stator blade 1 and the suction surface boundary layer. At the same time, the reduction of the first inlet metal angle and the second inlet metal angle can cause the blade bending angle to be reduced, thereby reducing the blade load and reducing the secondary flow, thereby further improving the end area flow near the stator blade 1.

[0050] In an illustrative embodiment, step S1 includes step S11 and step S12;

[0051] Step S11: Obtain the thickness of the lower end wall boundary layer δ h and the thickness of the boundary layer on the upper wall δ t ;

[0052] The boundary layer, also known as the boundary layer, refers to a thin layer where the velocity of the fluid changes dramatically near the surface of an object due to the viscosity of the fluid when the fluid flows around the object under a large Reynolds number. The upper end wall boundary layer refers to the boundary layer near the tip 12. The lower end wall boundary layer refers to the boundary layer near the root 11. By performing numerical simulation or testing on the transonic compressor cascade to be designed, the flow field structure can be obtained. Based on the obtained flow field structure, the thickness of the upper end wall boundary layer δ under the design condition can be determined. h and the lower end wall boundary layer thickness δ t .

[0053] Step S12: Based on the thickness of the lower end wall boundary layer δ h Determine the distance between the lower end wall stacking control position 14 and the blade root 11, the distance L between the end wall stacking control position and the blade root 11 1 Equal to 2-5 times the thickness of the lower end wall boundary layer δ h According to the thickness of the boundary layer on the upper wall δ t Determine the distance between the upper end wall stacking control position 15 and the blade tip 12 (total length of the stator blade 1 - L 2 ), the distance between the upper end wall stacking control position 15 and the blade tip 12 is equal to 2-5 times the upper end wall boundary layer thickness δ t .

[0054] Thus, according to the boundary layer thickness δ of the lower end wall h and the thickness of the boundary layer on the upper wall δ t The upper end wall stacking control position 15 and the lower end wall stacking control position 14 are determined so that the flow improvement area is concentrated in the end region of the stator blade 1 without causing adverse effects on other regions of the stator blade 1 .

[0055] In an illustrative embodiment, in step S2, by controlling the chordwise stacking of the primitive blade profile, the leading edge sweep angle in the area between the lower end wall stacking control position 14 and the blade root 11 is positive, and the leading edge sweep angle in the area between the upper end wall stacking control position 15 and the blade tip 12 is negative, and the leading edge sweep angle changes smoothly in the span direction of the stator blade 1.

[0056] In this embodiment, the chord direction is the direction from the trailing edge to the leading edge L. The leading edge sweep angle is changed by controlling the chord-wise stacking of the primitive blade profile, so that the stator blade 1 is swept forward in the area between the lower end wall stacking control position 14 and the blade root 11 and in the area between the upper end wall stacking control position 15 and the blade tip 12. This method of controlling the forward sweep of the leading edges L at both ends of the stator blade 1 is simple and easy.

[0057] The leading edge sweep angle is the angle between the leading edge stacking line and the perpendicular direction of the leading edge velocity vector (or geometric reference direction vector). The sweep angle is negative when the stacking line is tilted upstream, and positive otherwise.

[0058] In this embodiment, if Figures 7 to 10 As shown, the calculation formula of the leading edge sweep angle is as follows:

[0059]

[0060] The airflow velocity vector at the leading edge or the given geometric reference direction vector;

[0061] η: The angle between the projection on the r-θ plane and the radial direction is positive when a point moves from the root to the tip along the leading edge L and r increases and θ also increases;

[0062] μ: The angle between the projection on the xr plane and the radial direction is positive when a point moves from the root to the tip along the leading edge L and r increases and x also increases;

[0063] The slope angle of point P of the stream surface meridian projection on the leading edge L;

[0064] Beta: The angle between the projection on the x-θ plane and the axial direction is: The θ component of is positive in the positive direction of θ;

[0065] λ: leading edge sweep angle, and Intersection angle, if It is positive when the positive direction intersects the positive x direction at an acute angle;

[0066] v: dihedral angle, if the plane Ω B Positive θ plane and Ω S When the front angle is acute, it is positive, and 90-v is the surface Ω B The axisymmetric plane Ω S Angle;

[0067] Ω S : Rotating flow surface;

[0068] Ω B : The surface formed by the tangent line at point P on the leading edge L and the given (velocity) direction vector;

[0069] Ω L : unit vector and the surface formed by the unit vector θ;

[0070] 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 rotation direction of the hub is positive;

[0071] Unit vectors in all directions of global cylindrical coordinates;

[0072] The local coordinate system unit vector, The direction is consistent with the given (speed) direction vector, In the plane Ω B Internal vertical, Then, using the right-hand rule, perpendicular to and

[0073] Unit vector in the local coordinate system, In Ω B The tangent direction of the inner point P along the leading edge L is: In Ω L In the plane, Perpendicular to and

[0074] In step S2, the stacking of the elementary blade profile in the vertical chord direction is controlled so that the hub suction surface dihedral angle in the area between the lower end wall stacking control position 14 and the blade root 11 and the casing suction surface dihedral angle in the area between the upper end wall stacking control position 15 and the blade tip 12 are both obtuse angles.

[0075] In an exemplary embodiment, the leading edge sweep angle in the region between the lower end wall stacking control position 14 and the blade root 11 is greater than or equal to 10°, and the leading edge sweep angle in the region between the upper end wall stacking control position 15 and the blade tip 12 is less than or equal to -10°.

[0076] In this way, the load near the blade root 11 and the blade tip 12 of the stator blade 1 is further reduced, and the high load area is further moved backward, so that the angular zone separation is weakened and the separation starting point is further moved backward.

[0077] In an illustrative embodiment, Figure 5 , 6 As shown, the hub suction surface dihedral angle in the area between the lower end wall stacking control position 14 and the blade root 11 and the casing suction surface dihedral angle in the area between the upper end wall stacking control position 15 and the blade tip 12 are both greater than 95°.

[0078] Since the hub suction surface dihedral angle in the area near the blade root 11 of the stator blade 1 and the casing suction surface dihedral angle in the area near the blade tip 12 are both greater than 95°, the intersection between the end wall of the stator blade 1 and the suction surface boundary layer can be significantly reduced, thereby further weakening the angular zone separation.

[0079] The dihedral angle is the complementary angle of the inclination angle of the stacking line in the direction perpendicular to the velocity vector (or geometric reference direction vector).

[0080] In this embodiment, if Figures 7 to 10 As shown, the formula for calculating the dihedral angle is as follows:

[0081]

[0082] v hub =90+v

[0083] Velocity vector or given geometric reference direction vector;

[0084] η: The angle between the projection on the r-θ plane and the radial direction is positive when r increases and θ also increases when a point moves along the leading edge L;

[0085] μ: The angle between the projection on the xr plane and the radial direction is positive when r increases and x also increases when a point moves along the leading edge L;

[0086] The slope angle of point P of the stream surface meridian projection on the leading edge L;

[0087] Beta: The angle between the projection on the x-θ plane and the axial direction is: The θ component of is positive in the positive direction of θ;

[0088] λ: leading edge sweep angle, and Intersection angle, if It is positive when the positive direction intersects the positive x direction at an acute angle;

[0089] v: dihedral angle, if the plane Ω B Positive θ plane and Ω S When the front angle is acute, it is positive, and 90-v is the surface Ω B The axisymmetric plane Ω S Angle;

[0090] Ω S : Rotating flow surface;

[0091] Ω B : The surface formed by the tangent line at point P on the leading edge L and the given (velocity) direction vector;

[0092] Ω L : unit vector and the surface formed by the unit vector θ;

[0093] 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 rotation direction of the hub is positive;

[0094] Unit vectors in all directions of global cylindrical coordinates;

[0095] The local coordinate system unit vector, The direction is consistent with the given (speed) direction vector, In the plane Ω B Internal vertical, Then, using the right-hand rule, perpendicular to and

[0096] Unit vector in the local coordinate system, In Ω B The tangent direction of the interior point P, In Ω L In the plane, Perpendicular to and

[0097] In an exemplary embodiment, a first inlet metal angle of the basic airfoil in the area between the lower endwall stack control position 14 and the blade root 11 and a second inlet metal angle of the basic airfoil in the area between the upper endwall stack control position 15 and the blade tip 12 are 5°-25°.

[0098] The first inlet metal angle and the second inlet metal angle of 5°-25° can further reduce the blade load and the secondary flow, thereby further improving the end area flow close to the stator blade 1.

[0099] The present application also proposes a stator blade 1 , which is shaped by stacking the above-mentioned stator blades 1 .

[0100] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0101] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include at least one of the features.

[0102] In the description of the present application, “plurality” means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0103] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0104] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0105] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0106] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for controlling the sweep and dihedral angle stacking of stationary blades to improve the flow in the end zone, characterized in that: include: An upper end wall stacking control position and a lower end wall stacking control position are set on the stator blade in an area between the tip and the root of the stator blade, wherein the upper end wall stacking control position is closer to the tip than the lower end wall stacking control position; The blade profile of the stator blade is determined by the primitive blade profile stacking method, so that the stator blade is swept forward in the area between the lower end wall stacking control position and the blade root and in the area between the upper end wall stacking control position and the blade tip, and the hub suction surface dihedral angle in the area between the lower end wall stacking control position and the blade root and the casing suction surface dihedral angle in the area between the upper end wall stacking control position and the blade tip are both obtuse angles, the hub suction surface dihedral angle is the angle between the suction surface of the stator blade and the outer peripheral surface of the hub, and the casing suction surface dihedral angle is the angle between the suction surface of the stator blade and the inner peripheral surface of the casing.

2. The control method according to claim 1, characterized in that: Also includes: The first inlet metal angle of the primitive airfoil in the area between the lower end wall stacking control position and the blade root is reduced to increase the hub suction surface dihedral angle, and the second inlet metal angle of the primitive airfoil in the area between the upper end wall stacking control position and the blade tip is reduced to increase the casing suction surface dihedral angle.

3. The control method according to claim 1, characterized in that: An upper end wall stacking control position and a lower end wall stacking control position are set in an area between a blade tip and a blade root of a stator blade, including: Get the lower end wall boundary layer thickness δ h and the thickness of the boundary layer on the upper wall δ t ; According to the thickness of the lower end wall boundary layer δ h Determine the distance between the lower end wall stacking control position and the blade root, according to the upper end wall boundary layer thickness δ t Determine the distance from the upper endwall stack control location to the blade tip.

4. The control method according to claim 3, characterized in that: The distance L1 between the end wall stacking control position and the blade root is equal to 2-5 times the lower end wall boundary layer thickness δ h , the distance between the upper end wall stacking control position and the blade tip is equal to 2-5 times the upper end wall boundary layer thickness δ t .

5. The control method according to claim 1, characterized in that: The method of determining the blade profile of the stator blade by using the primitive blade profile stacking method comprises: By controlling the chord-wise stacking of the primitive blade profile, the leading edge sweep angle in the area between the lower end wall stacking control position and the blade root is positive, the leading edge sweep angle in the area between the upper end wall stacking control position and the blade tip is negative, and the leading edge sweep angle changes smoothly in the span direction of the stator blade; By controlling the stacking of the elementary blade profile in the vertical chord direction, the hub suction surface dihedral angle in the area between the lower end wall stacking control position and the blade root and the casing suction surface dihedral angle in the area between the upper end wall stacking control position and the blade tip are both obtuse angles.

6. The control method according to claim 5, characterized in that: The leading edge sweep angle in the area between the lower end wall overlap control position and the blade root is greater than or equal to 10°, and the leading edge sweep angle in the area between the upper end wall overlap control position and the blade tip is less than or equal to -10°.

7. The control method according to claim 2, characterized in that: The hub suction surface dihedral angle in the area between the lower end wall stacking control position and the blade root and the casing suction surface dihedral angle in the area between the upper end wall stacking control position and the blade tip are both greater than 95°.

8. The control method according to claim 2, characterized in that: The first inlet metal angle and the second inlet metal angle are 5°-25°.

9. The control method according to claim 8, characterized in that: The first inlet metal angle and the second inlet metal angle vary smoothly in the span direction of the stator blade.

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