A control method for improving end region flow by stacking of blade sweep and dihedral

Abstract

A control method of stator blade sweep and dihedral angle stacking for improving end region flow, the stacking method comprising setting an upper end wall stacking control position and a lower end wall stacking control position on the stator blade in a region between the blade tip and the blade root of the stator blade, wherein the upper end wall stacking control position is closer to the blade tip than the lower end wall stacking control position; determining the blade profile of the stator blade by using a base element profile stacking method, so that the stator blade is swept forward in the region between the lower end wall stacking control position and the blade root and in the region between the upper end wall stacking control position and the blade tip, and so that 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 obtuse. The stator blade obtained by using the method can reduce the total pressure loss in the end region by more than 20%.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aviation propulsion technology, and particularly relates to a control method for improving end region flow by means of static blade sweep and dihedral stacking. BACKGROUND

[0002] Three-dimensional flow separation in the corner region formed by the suction surface of the existing axial fan / compressor blade and the end wall has been determined as an inherent flow characteristic. With the development trend of using higher load blades to achieve higher single-stage work input, the development of corner region flow separation will be aggravated due to the increase of the adverse pressure gradient on the suction surface and the increase of static pressure rise in the blade passage, and even corner region stall will be induced. In high load static blades, the end region flow is more severe due to large bending angle and thick incoming boundary layer, and a large number of research results show that the complex end region flow loss can account for more than 30% of the total compressor loss, and the loss will become more severe with the increase of load.

[0003] Blade stacking technology started from the early stage of borrowing the design method of external flow airfoils. The first generation of three-dimensional blades were stacked according to different twist directions, and the second generation of three-dimensional blades were designed to match the spanwise distribution of the basic element load through so-called blade bending and sweep stacking. Suppressing boundary layer separation and adjusting shock wave structure to reduce compressor blade loss has become an essential design method for designers, although the technology has gradually entered the stage of engineering application, but there is still no blade stacking method for the end region of static blades, which leads to the inability to maximize the potential of blade stacking technology to improve compressor load. SUMMARY

[0004] The technical problem to be solved by the present application is how to reduce the total pressure loss of the stator blade end region.

[0005] The embodiment of the present application provides a control method for improving end region flow by means of static blade sweep and dihedral stacking, which comprises the following steps:

[0006] An upper end wall stacking control position and a lower end wall stacking control position are arranged on the stator blade in a region 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] A basic element blade profile stacking method is used to determine the blade profile of the stator blade, so that the region between the lower end wall stacking control position and the root and the region between the upper end wall stacking control position and the tip are both forward swept, and the dihedral angle of the hub suction surface in the region between the lower end wall stacking control position and the root and the dihedral angle of the casing suction surface in the region between the upper end wall stacking control position and the tip are both obtuse. The dihedral angle of the hub suction surface is the included angle between the suction surface of the stator blade and the outer circumferential surface of the hub, and the dihedral angle of the casing suction surface is the included angle between the suction surface of the stator blade and the inner circumferential surface of the casing.

[0008] In an illustrative embodiment, further comprising:

[0009] reducing a first inlet metal angle of the elementary blade profile in the region between the lower endwall stacking control location and the blade root to increase the hub suction surface dihedral angle, and reducing a second inlet metal angle of the elementary blade profile in the region between the upper endwall stacking control location and the blade tip to increase the casing suction surface dihedral angle.

[0010] In an illustrative embodiment, the upper endwall stacking control location and the lower endwall stacking control location are disposed on the stator blade in a region between a tip of the stator blade and a root of the stator blade, comprising:

[0011] obtaining a lower endwall boundary layer thickness δ h and an upper endwall boundary layer thickness δ t ;

[0012] determining a distance between the lower endwall stacking control location and the blade root based on the lower endwall boundary layer thickness δ h and determining a distance between the upper endwall stacking control location and the blade tip based on the upper endwall boundary layer thickness δ t .

[0013] In an illustrative embodiment, the distance L1 between the endwall stacking control location and the blade root is equal to 2-5 times the lower endwall boundary layer thickness δ h , and the distance between the upper endwall stacking control location and the blade tip is equal to 2-5 times the upper endwall boundary layer thickness δ t .

[0014] In an illustrative embodiment, the method of determining the blade profile of the stator blade using the elementary blade profile stacking method, comprising:

[0015] controlling the stacking of the elementary blade profile in chordwise direction such that a positive leading edge sweep angle in the region between the lower endwall stacking control location and the blade root and a negative leading edge sweep angle in the region between the upper endwall stacking control location and the blade tip, and the leading edge sweep angle varies smoothly in spanwise direction of the stator blade;

[0016] controlling the stacking of the elementary blade profile in vertical chordwise direction such that the hub suction surface dihedral angle in the region between the lower endwall stacking control location and the blade root and the casing suction surface dihedral angle in the region between the upper endwall stacking control location and the blade tip are both obtuse.

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

[0018] In one illustrative embodiment, the dihedral angle of the hub suction surface in the area between the lower endwall stacking control position and the blade root and the dihedral angle of the casing suction surface in the area between the upper endwall stacking control position and the blade tip are both greater than 95°.

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

[0020] In one illustrative embodiment, the first inlet metal angle and the second inlet metal angle vary smoothly in the spanwise direction of the stator blade.

[0021] The stator blade obtained by using the control method described above is forward swept in the areas near the blade root and the blade tip, thereby changing the load matching in the spanwise direction of the stator blade, reducing the load near the blade root and the blade tip of the stator blade, and moving the high load area backward, so as to weaken the corner separation and move the separation start point backward. Meanwhile, since the dihedral angle of the hub suction surface in the area near the blade root and the dihedral angle of the casing suction surface in the area near the blade tip of the stator blade are both large, the intersection of the endwall and the suction surface boundary layer of the stator blade is reduced, so as to weaken the corner separation. The stator blade 1 obtained by using the method can reduce the total pressure loss in the end region by more than 20%.

[0022] Other features and advantages of the present application will be set forth in the description that follows, and in part will be apparent from the description, or can be learned by practice of the present application. Other advantages of the present application will be realized and attained by the methods and solutions particularly pointed out in the description. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings are included to provide an understanding of the present application, and are incorporated in and constitute a part of the specification, illustrate embodiments of the present application, and, together with the description, serve to explain the principles of the present application, and do not limit the present application.

[0024] Figure 1 FIG. 1 is a front view of a stator blade according to an embodiment of the present application;

[0025] Figure 2 FIG. 2 is a cross-sectional view of the end region of the stator blade according to an embodiment of the present application;

[0026] Figure 3 FIG. 3 is a perspective view of the stator blade according to an embodiment of the present application;

[0027] Figure 4 FIG. 4 is a distribution of the forward sweep angle of the leading edge of the stator blade in the spanwise direction according to an embodiment of the present application;

[0028] Figure 5 FIG. 5 is a distribution of the dihedral angle of the hub of the stator blade in the chordwise direction according to an embodiment of the present application;

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

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

[0031] Figure 8 A schematic view of a stator blade in the perpendicular meridian direction in an embodiment of the present application;

[0032] Figure 9 A three-dimensional schematic view of a stator blade in an embodiment of the present application;

[0033] Figure 10 A schematic view of the rotation direction of a stator blade in an embodiment of the present application. DETAILED DESCRIPTION

[0034] The present application describes multiple embodiments, but the description is exemplary rather than limiting, and it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are within the scope of the embodiments described in the present application. Although many possible combinations of features are shown in the drawings and discussed in the specification, many other combinations of the disclosed features are possible. Unless specifically intended otherwise, any feature or element of any embodiment can be used with any other feature or element of any other embodiment, or in any other embodiment, or in a new 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 can also be combined with any conventional features or elements to form unique inventive solutions. 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 the present application can be implemented alone or in any suitable combination. Embodiments are, therefore, not to be limited by other than in accordance with the claims as they may be later amended, and any equivalents. Moreover, various modifications and changes can be made within the scope of the following claims.

[0036] Furthermore, in describing representative embodiments, the specification may have presented methods and / or processes as a specific sequence of steps. However, the method or process should not be limited to the specific order of steps described herein, to the extent that it does not depend on such a specific order. As will be understood by those skilled in the art, other sequences of steps are also possible. Therefore, the specific order of steps set forth in the specification should not be construed as a limitation of the claims. Moreover, the claims concerning the method and / or process should not be limited to the steps performed in the written order, and those skilled in the art will readily understand that these orders can be varied and still remain within the spirit and scope of the embodiments of this application.

[0037] This application provides a method for controlling blade sweep and dihedral overlap to improve end-region flow. The method includes the following steps:

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

[0039] The stator blade 1 has a blade tip 12 and a blade root 11, which are the two opposite ends of the stator blade 1. The blade tip 12 is the end of the stator blade 1 closer to the housing, and the blade root 11 is the end of the stator blade 1 closer to the hub. The spanwise direction of the stator blade 1 is from the blade root 11 to the blade tip 12. In the spanwise direction of the stator blade 1, the blade root 11, the lower wall accumulation control position 14, the upper wall accumulation control position 15, and the blade tip 12 are arranged sequentially. The upper wall accumulation control position 15 is closer to the blade tip 12, and the lower wall accumulation control position 14 is closer to the blade root 11.

[0040] Step S2: The blade shape of the stator blade 1 is determined by the basic blade shape stacking method, such that the area between the lower end wall stacking control position 14 and the blade root 11 and the area between the upper end wall stacking control position 15 and the blade tip 12 of the stator blade 1 are both swept forward, 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] A basic leaf shape refers to a representative micro-leaf shape unit obtained by infinitely subdividing a stator blade 1 along a certain direction (e.g., the spanwise or tangential direction of the stator blade 1). A basic leaf shape can be any existing known basic leaf shape of a stator blade 1. The basic leaf shape stacking method is a method of combining a series of basic leaf shapes in a certain way to form a complete blade.

[0042] The stator blade 1 comprises a leading edge L and a trailing edge 13. The leading edge L is the edge of the stator blade 1 that is first contacted by the airflow, and is the starting end of the profile curve in the flow-in direction of the airflow. The trailing edge 13 is the other edge of the stator blade 1 opposite to the leading edge L. The forward sweep of the region between the lower end wall stacking control position 14 and the blade root 11 of the stator blade 1 refers to the forward inclination of the leading edge L of the stator blade 1 in this region, or in other words, the forward extension of the stator blade 1 in this region. The forward sweep of the region between the upper end wall stacking control position 15 and the blade tip 12 of the stator blade 1 refers to the forward inclination of the leading edge L of the stator blade 1 in this region, or in other words, the forward extension of the stator blade 1 in this region.

[0043] The suction surface is the side of the stator blade 1 that forms a low pressure area when the fluid flows through the stator blade 1. The end wall refers to the wall surface that defines the boundary of the flow passage, usually including the outer peripheral wall of the hub of the impeller and the inner peripheral wall of the casing, and plays a role in restraining and guiding the fluid flow. The dihedral angle refers to the included angle between the end wall and the suction surface, which describes the relative position and inclination degree of the end wall and the suction surface in three-dimensional space from the spatial angle.

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

[0045] In the embodiments of the present application, the stator blade 1 obtained by using the above control method is forward swept in the regions close to the blade root 11 and the blade tip 12, so that the load distribution in the spanwise direction of the stator blade 1 is changed, 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, thereby weakening the corner separation and moving the separation start point backward. At the same time, the hub suction surface dihedral angle of the region close to the blade root 11 and the casing suction surface dihedral angle of the region close to the blade tip 12 of the stator blade 1 are both large, which can reduce the intersection of the end wall and the boundary layer of the suction surface of the stator blade 1, thereby weakening the corner separation. The stator blade 1 obtained by using the method can reduce the total pressure loss in the end region by more than 20%.

[0046] In one illustrative embodiment, the step S2 is followed by a step S3.

[0047] Step S3: as shown in Figure 2 the first inlet metal angle of the elementary blade profile in the region 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 region between the lower end wall stacking control position 14 and the blade root 11, and the second inlet metal angle of the elementary blade profile in the region 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 region between the upper end wall stacking control position 15 and the blade tip 12.

[0048] The inlet metal angle is the included angle between the camber line of the stator blade and the axial direction of the hub. The axial direction of the hub in the present application refers to the axial direction of the hub at the position where the stator blade is located. The first inlet metal angle and the second inlet metal angle vary smoothly in the spanwise direction of the stator blade 1. The hub suction surface dihedral angle in the region between the lower end wall accumulation control position 14 and the blade root 11 and the casing suction surface dihedral angle in the region between the upper end wall accumulation control position 15 and the blade tip 12 vary smoothly in the chordwise direction.

[0049] In this way, by further increasing the angles of the hub suction surface dihedral angle and the casing suction surface dihedral angle through reducing the first inlet metal angle of the region close to the blade root 11 and the second inlet metal angle of the region close to the blade tip 12 of the stator blade 1, the end wall and the suction surface boundary layer of the stator blade 1 can be further reduced, and the blade bending angle caused by the reduction of the first inlet metal angle and the second inlet metal angle can be further reduced, thereby reducing the blade load and the secondary flow, and further improving the flow close to the end region of the stator blade 1.

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

[0051] Step S11: obtaining the lower end wall boundary layer thickness δ h and the upper end wall boundary layer thickness δ t .

[0052] The boundary layer, also known as the boundary layer, refers to a thin layer close to the surface of an object when a fluid flows around the object at a large Reynolds number, and the flow velocity changes sharply due to the viscosity of the fluid. The upper end wall boundary layer refers to the boundary layer close to the blade tip 12. The lower end wall boundary layer refers to the boundary layer close to the blade root 11. Numerical simulation or test can be performed on the transonic compressor cascade to be designed to obtain the flow field structure, and the upper end wall boundary layer thickness δ h and the lower end wall boundary layer thickness δ t under the design condition can be determined according to the obtained flow field structure.

[0053] Step S12: determining the distance between the lower end wall accumulation control position 14 and the blade root 11 according to the lower end wall boundary layer thickness δ h , and the distance L1 between the end wall accumulation control position and the blade root 11 is equal to 2-5 times the lower end wall boundary layer thickness δ h . Determining the distance (total length of the stator blade 1-L2) between the upper end wall accumulation control position 15 and the blade tip 12 according to the upper end wall boundary layer thickness δ t , and the distance between the upper end wall accumulation 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 lower end wall boundary layer thickness δ h and the upper end wall boundary layer thickness δ t The upper end wall accumulation control position 15 and the lower end wall accumulation control position 14 are determined so that the flow improvement area is concentrated in the end region of the stator blade 1 without adversely affecting other regions of the stator blade 1.

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

[0056] In the present embodiment, the chordwise direction is the direction from the trailing edge to the leading edge L, and by controlling the chordwise accumulation of the base element airfoil to change the magnitude of the leading edge sweep angle, the stator blade 1 is made to sweep forward in both the region between the lower end wall accumulation control position 14 and the blade root 11 and the region between the upper end wall accumulation control position 15 and the blade tip 12, and this method of controlling the leading edge L of both ends of the stator blade 1 to sweep forward is simple and easy to implement.

[0057] The leading edge sweep angle is the angle between the leading edge accumulation line and the perpendicular direction of the leading edge velocity vector (or the geometric reference direction vector), and the accumulation line is inclined upstream, and the sweep angle is negative, and vice versa.

[0058] In the present embodiment, as shown in Figures 7 to 10 The calculation formula of the leading edge sweep angle is as follows:

[0059]

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

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

[0062] μ: The x-r plane projection and the radial angle, when a point moves along the leading edge L from the blade root to the blade tip, r increases and x also increases, and it is positive;

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

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

[0065] λ: leading edge sweep angle, with the angle between the positive x-direction and the positive y-direction is acute if positive if the positive x-direction intersects the positive y-direction at an acute angle;

[0066] v: dihedral angle, if the plane Ω B positive if the positive x-direction intersects the positive y-direction at an acute angle; S positive if the positive x-direction intersects the positive y-direction at an acute angle, 90-v is the dihedral angle of the plane Ω B with the axisymmetric plane Ω S included angle;

[0067] Ω S : surface of revolution;

[0068] Ω B : surface spanned by the tangent to the leading edge L at point P and a given (velocity) direction vector;

[0069] Ω L : surface spanned by the unit vector and 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, the direction of rotation of the hub is positive;

[0071] global cylindrical coordinate unit vectors;

[0072] local coordinate system unit vectors, in the same direction as a given (velocity) direction vector, in the plane Ω B is perpendicular to in the right-hand rule sense, then is perpendicular to and

[0073] local coordinate system unit vectors, at point P in Ω B is the tangent to the leading edge L, in the plane Ω L is perpendicular to in the right-hand rule sense, and

[0074] In step S2, the hub suction surface dihedral angle in the region between the lower endwall stacking control position 14 and the blade root 11 and the casing suction surface dihedral angle in the region between the upper endwall stacking control position 15 and the blade tip 12 are both made obtuse by controlling the stacking of the base element airfoil normal chordwise direction.

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

[0076] In this way, the load near the leaf root 11 and leaf tip 12 of the static leaf 1 is further reduced, the high load zone is further shifted backward, thereby weakening the corner separation and further shifting the separation starting point backward.

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

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

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

[0080] In this embodiment, as 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 onto the r-θ plane and the radial direction is positive when r increases and θ also increases as a point moves along the leading edge L.

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

[0086] The slope angle of point P on the leading edge L as the meridional projection of the flow surface;

[0087] β: The angle between the projection onto the x-θ plane and the axis. The θ component is positive in the positive θ direction;

[0088] λ: leading edge sweep angle, with the intersection angle is positive if positive if the positive x-direction intersects the positive θ-direction at an acute angle;

[0089] v: dihedral angle, if the plane Ω B positive if the positive θ-direction intersects the plane Ω S at an acute angle, 90-v is the dihedral angle of the plane Ω B with the axis of symmetry Ω S included angle;

[0090] Ω S : surface of revolution;

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

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

[0093] x, r, θ: global cylindrical coordinates, x is the axial direction, r is the radial direction, and θ is the circumferential direction, with the positive direction of rotation;

[0094] global cylindrical coordinate unit vectors;

[0095] local coordinate system unit vectors, in the same direction as a given (velocity) direction vector, normal to the plane Ω B in the plane Ω , then normal to and

[0096] local coordinate system unit vectors, tangent to Ω B at point P, in the plane Ω L , normal to and

[0097] In one exemplary embodiment, the first inlet metal angle of the base blade profile in the region between the lower endwall stacking control location 14 and the blade root 11 and the second inlet metal angle of the base blade profile in the region between the upper endwall stacking control location 15 and the blade tip 12 is 5°-25°.

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

[0099] The application further provides a stator blade 1 which adopts the laminated structure of the above stator blade 1.

[0100] 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” and the like is based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0101] In addition, the terms “first”, “second”, and the like are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with “first”, “second”, and the like can explicitly or implicitly include at least one of the features.

[0102] In the description of the present application, the meaning of “a plurality of” is at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0103] In the present application, unless otherwise explicitly specified and limited, the terms “mounting”, “connection”, “connection”, “fixing” and the like should be understood in a broad sense, for example, “connection” can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0104] In the present application, unless specifically defined and limited otherwise, the first feature "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 indirectly in contact through an intermediate medium. Moreover, the first feature "over", "above" and "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height. The first feature "under", "below" and "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the first feature is lower than the second feature in horizontal height.

[0105] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" etc. 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 the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present application 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 limiting the present application, and the person skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A method of controlling the stacking of the pitch and the dihedral of a stationary blade for improving the flow in the end region, characterized in that Comprising: an upper endwall stacking control location and a lower endwall stacking control location are provided on the stator blade in a region between a tip of the stator blade and a root of the stator blade, wherein the upper endwall stacking control location is closer to the tip than the lower endwall stacking control location; a blade profile of the stator blade is determined by a blade element stacking method, such that the region between the lower endwall stacking control location and the root and the region between the upper endwall stacking control location and the tip are both forward swept, and such that a hub suction surface dihedral angle in the region between the lower endwall stacking control location and the root and a casing suction surface dihedral angle in the region between the upper endwall stacking control location and the tip are both obtuse, the hub suction surface dihedral angle being an included angle between a suction surface of the stator blade and an outer peripheral surface of a hub, and the casing suction surface dihedral angle being an included angle between the suction surface of the stator blade and an inner peripheral surface of a casing.

2. The control method according to claim 1, characterized by, Further comprising: a first inlet metal angle of the blade element in the region between the lower endwall stacking control location and the root is reduced to increase the hub suction surface dihedral angle, and a second inlet metal angle of the blade element in the region between the upper endwall stacking control location and the tip is reduced to increase the casing suction surface dihedral angle.

3. The control method according to claim 1, characterized by, An upper endwall stacking control location and a lower endwall stacking control location are provided on the stator blade in a region between a tip of the stator blade and a root of the stator blade, comprising: acquiring a lower end wall boundary layer thickness δ h and an upper end wall boundary layer thickness δ t ; determining the distance between the lower endwall accumulation control location and the blade root based on the upper endwall boundary layer thickness δ h determining the distance between the lower endwall accumulation control location and the blade root based on the upper endwall boundary layer thickness δ t determining the distance between the upper endwall accumulation control location and the blade tip.

4. The control method according to claim 3, characterized by The distance between the lower end wall accumulation control position and the blade root L 1 is equal to 2-5 times the lower end wall boundary layer thickness δ h The distance between the upper end wall accumulation 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 by, The blade profile of the stator blade is determined by a blade element stacking method, comprising: by controlling a chordwise stacking of the blade element, such that a leading edge sweep angle in the region between the lower endwall stacking control location and the root is positive, and a leading edge sweep angle in the region between the upper endwall stacking control location and the tip is negative, the leading edge sweep angles being smoothly varied in a spanwise direction of the stator blade; by controlling a stacking in a perpendicular chordwise direction of the blade element, such that the hub suction surface dihedral angle in the region between the lower endwall stacking control location and the root and the casing suction surface dihedral angle in the region between the upper endwall stacking control location and the tip are both obtuse.

6. The control method according to claim 5, characterized by The leading edge sweep angle in the region between the lower endwall stacking control location and the root is greater than or equal to 10°, and the leading edge sweep angle in the region between the upper endwall stacking control location and the tip is less than or equal to -10°.

7. The control method according to claim 2, characterized by, The hub suction surface dihedral angle in the region between the lower endwall stacking control location and the root and the casing suction surface dihedral angle in the region between the upper endwall stacking control location and the tip are both greater than 95°.

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

9. The control method according to claim 8, characterized by, The first inlet metal angle and the second inlet metal angle are smoothly varied in the spanwise direction of the stator blade.

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