Method of designing a compressor blade

Abstract

The application provides a design method of a compressor blade, and relates to the technical field of compressor blade profile design of gas turbines and aero-engine, and the method comprises the following steps: obtaining shape constraint parameters for designing the compressor blade, wherein the shape constraint parameters comprise a blade tip position, a blade root position, a blade tip deviation angle and a blade root deviation angle; determining a design shape of the blade according to a first position deviation degree of a first intersection point between a first reference line and a plane where the blade root position is located relative to the blade root position, and a second position deviation degree of a second intersection point between a second reference line and a plane where the blade tip position is located relative to the blade tip position; determining a plurality of control points matched with the design shape according to a third intersection point between the first reference line and the second reference line; and determining design parameters for designing the compressor blade according to the plurality of control points.

Description

Technical Field

[0001] This application relates to the field of gas turbine and aero-engine compressor blade design technology, and more specifically to a compressor blade design method. Background Technology

[0002] In the three-dimensional airfoil design of compressor blades for gas turbines or aero engines, the relevant methods have the following problems: the number of control parameters used to design three-dimensional airfoils increases linearly or even superlinearly with the complexity of the shape; after the increase of control parameters, it is difficult to ensure the smoothness and numerical stability of the blade surface at the same time; the range of airfoils to which the relevant methods are applicable is limited, and it is difficult to express both "bending" and "sweeping" geometric features simultaneously within a single mathematical framework. Summary of the Invention

[0003] In view of the above problems, this application provides a compressor blade design method, comprising: obtaining shape constraint parameters for designing the compressor blade, the shape constraint parameters including: blade tip position, blade root position, blade tip deviation angle, and blade root deviation angle, wherein the blade tip deviation angle includes the deflection angle of the blade tip position relative to the reference direction from the blade root to the blade tip, and the blade root deviation angle includes the deflection angle of the blade root position relative to the reference direction; constructing a first reference line and a second reference line according to the shape constraint parameters; determining the design shape of the blade according to a first position deviation of the first intersection point of the first reference line and the plane where the blade root position is located relative to the blade root position, and a second position deviation of the second intersection point of the second reference line and the plane where the blade tip position is located relative to the blade tip position; determining a plurality of control points matching the design shape according to a third intersection point; and determining design parameters for designing the compressor blade according to the plurality of control points.

[0004] According to an embodiment of this application, the blade root position includes the position of the center of gravity of the end section of the blade located on the compressor disk side, and the blade tip position includes the position of the center of gravity of the end section of the blade located away from the compressor disk side.

[0005] According to an embodiment of this application, constructing a first reference line based on shape constraint parameters includes: determining a reference angle relative to the horizontal direction of the line connecting the leaf root to the leaf tip based on the leaf tip position and the leaf root position; determining the sum of the reference angle and the leaf tip deviation angle to obtain a first direction angle; and constructing a ray along the first direction angle with the leaf root position as the starting point to obtain the first reference line.

[0006] According to an embodiment of this application, constructing a second reference line based on shape constraint parameters includes: obtaining a second direction angle based on the sum of a reference angle and a leaf root deviation angle; and constructing a ray along the second direction angle with the leaf root position as the starting point to obtain the second reference line.

[0007] According to an embodiment of this application, determining the design shape of a blade based on a first positional deviation of the first intersection point of the first reference line and the plane where the blade root is located relative to the blade root position, and a second positional deviation of the second intersection point of the second reference line and the plane where the blade tip is located relative to the blade tip position, includes: when the product of the first positional deviation and the second positional deviation is less than a preset value, the design shape is determined to be a first shape, wherein the first shape indicates that the blade root and the blade tip are bent in opposite directions; when the product of the first positional deviation and the second positional deviation is greater than or equal to the preset value, the design shape is determined to be a second shape, wherein the second shape includes: the blade root and the blade tip are bent in the same direction.

[0008] According to an embodiment of this application, when the preset shape includes a first shape, determining the positions of multiple control points corresponding to the shape to be set according to the third intersection point includes: determining a first position of the foot of the perpendicular from the third intersection point to the plane where the leaf root is located, and a second position of the foot of the perpendicular from the third intersection point to the plane where the leaf tip is located. Based on the first position, the second position, the leaf tip position, and the leaf root position, determining the positions of multiple control points corresponding to the first shape.

[0009] According to an embodiment of this application, determining the positions of multiple control points corresponding to a first shape based on a first position, a second position, a leaf tip position, and a leaf root position includes: determining the position of a first intermediate control point relative to the leaf root position and the first position between the leaf root position and the first position based on a preset first parameter; and determining the position of a second intermediate control point relative to the leaf tip position and the second position between the leaf tip position and the second position based on a preset second parameter; wherein the values ​​of the first parameter and the second parameter are between 0 and 1.

[0010] According to an embodiment of this application, when the preset shape includes a second shape, determining multiple control points corresponding to the shape to be set based on the third intersection point includes: determining multiple control points corresponding to the second shape based on the leaf root position, the third intersection point, and the leaf tip position.

[0011] According to an embodiment of this application, determining the design parameters of a blade based on multiple control points includes: generating a Bézier curve based on the multiple control points; using the Bézier curve as the stacking line of the blade, and determining the design parameters of the blade based on the stacking line; wherein the design parameters include at least the degree of curvature and the degree of tilt of the blade.

[0012] According to an embodiment of this application, the compressor blade design method further includes: when the first reference line is parallel to the second reference line, a preset point is used as the third intersection point; when the first reference line coincides with the second reference line, the midpoint between the blade root position and the blade tip position is used as the third intersection point. Attached Figure Description

[0013] The above-mentioned contents, other objects, features and advantages of this application will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0014] Figure 1 A flowchart illustrating a compressor blade design method according to an embodiment of this application is shown schematically.

[0015] Figure 2 A flowchart illustrating a method for designing compressor blades according to another embodiment of this application is shown schematically.

[0016] Figure 3 This schematic diagram illustrates a design reference point corresponding to a first shape according to an embodiment of this application;

[0017] Figure 4 A schematic diagram illustrating a design reference point corresponding to the second shape according to an embodiment of this application is shown.

[0018] Figure 5 This illustration schematically shows a sweeping overlay parameter scan according to an embodiment of the present application;

[0019] Figure 6 A schematic diagram illustrating a compressor blade design method according to an embodiment of this application is shown. Detailed Implementation

[0020] The embodiments of this application will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of this application. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of this application for ease of explanation. However, it will be apparent that one or more embodiments may be implemented without these specific details. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0021] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The terms “comprising,” “including,” etc., as used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0022] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0023] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0024] Therefore, there is an urgent need for a novel blade design method that "achieves higher degrees of freedom of variation with fewer control parameters and supports simultaneous bend-swept control".

[0025] For the three-dimensional airfoil design of gas turbine and aero-engine compressor blades, the following three types of stacked line construction methods are commonly used:

[0026] A combination of single circular arcs and straight lines can be used. For example, a single circular arc or straight line can be used as the superposition line, and the centroid coordinates can be given through 10 to 20 discrete cross-sections, and then spline or linear interpolation can be used for fitting.

[0027] Alternatively, a multi-segment low-order spline method can be used. For example, the superposition line can be divided into 3 to 5 quadratic or cubic splines, each segment requiring 3 to 4 control parameters, for a total of 12 to 20 control parameters.

[0028] Alternatively, a fully parameterized high-order spline method can be used. For example, 5th to 7th order B-splines or non-uniform rational B-splines can be directly used, with more than 30 control parameters that can be globally adjusted through optimization algorithms.

[0029] However, the relevant methods have the following problems: the order of circular arcs and low-order polynomial basis functions is too low, and the geometric expression ability must be compensated by increasing discrete cross sections, resulting in the expansion of control parameters; the lack of explicit curvature constraints and convex hull guarantees leads to abrupt changes in local curvature; different families of curves are used for bending and sweeping respectively, and the mathematical models are not unified, making coupling optimization difficult.

[0030] For example, on the one hand, there are problems of redundant control parameters and chaotic dimensions. For instance, the number of control parameters in multi-segment low-order spline methods and fully parameterized high-order spline methods increases linearly or even superlinearly with the complexity of the shape, resulting in high dimensionality of optimization variables, huge search space, and the surface is prone to redundant inflection points. Local curvature abrupt changes can cause airflow separation, and it can also lead to the accumulation of manufacturing tolerances and large deviations between the finished product and the design model.

[0031] On the other hand, there is the challenge of decoupling the bending and sweeping characteristics. In the three-dimensional airfoil design of gas turbine and aero-engine compressor blades, it is generally desirable to obtain sufficient geometric degrees of freedom in both the "bending" and "sweeping" dimensions simultaneously, in order to further improve efficiency and surge margin without sacrificing pressure ratio and structural strength. However, related technologies struggle to strike a balance between the "number of control parameters" and the "degrees of freedom in shaping." If there are too many control parameters, optimization dimensions explode, surfaces become rough, and manufacturing errors are amplified; if there are too few control parameters, the geometric expression capability is insufficient, making it impossible to finely adjust both bending and sweeping characteristics simultaneously.

[0032] For example, the circular arc / low-order spline method is difficult to express both "bending" and "sweeping" geometric features simultaneously within a single mathematical framework. It often requires step-by-step iteration: first determine the sweeping shape and then modify the bending shape or vice versa. This results in a large number of iterations and a long cycle in the design analysis. Furthermore, the bending and sweeping are mutually restrictive and easily get stuck in local optima, making it impossible to obtain the globally optimal solution.

[0033] On the other hand, the applicable range of blade types for the relevant methods is limited. For example, the combination of single circular arc and straight line is only applicable to blade types with low sweep and low load. For high-load fan or compressor rotors with high pressure ratio, large sweep, and transonic speed, the geometric expression capability is obviously insufficient, resulting in insufficient design margin and early surge boundary. Therefore, it is necessary to add additional stages or bleed valves, which increases weight and complexity.

[0034] In addition, the relevant methods also have the problem of contradiction between smoothness and accuracy. For example, although high-order splines can theoretically achieve high accuracy, it is difficult to ensure both surface smoothness and numerical stability at the same time as the number of control parameters increases. In actual processing, manual shaping is required, resulting in lower accuracy.

[0035] In view of this, embodiments of this application provide a method for designing compressor blades.

[0036] Figure 1 A flowchart illustrating a method for designing compressor blades according to an embodiment of this application is shown schematically.

[0037] Figure 2 A flowchart illustrating a method for designing compressor blades according to another embodiment of this application is shown schematically.

[0038] like Figure 1 As shown, the compressor blade design method of this embodiment includes operations S110 to S150.

[0039] In operation S110, shape constraint parameters for designing compressor blades are obtained. The shape constraint parameters include: blade tip position, blade root position, blade tip deviation angle, and blade root deviation angle. The blade tip deviation angle includes the deflection angle of the blade tip position relative to the reference direction from the blade root to the blade tip, and the blade root deviation angle includes the deflection angle of the blade root position relative to the reference direction.

[0040] like Figure 2 As shown, shape constraint parameters can be input to determine the blade's design parameters based on these parameters.

[0041] For example, the values ​​of shape constraint parameters can be predetermined based on the aerodynamic performance requirements and structural strength requirements of the compressor.

[0042] For example, the blade tip position can include a pre-set axial coordinate corresponding to the blade tip, such as 220 mm to 236 mm, so that the airflow can flow smoothly from the blade root to the blade tip, avoiding separation, blockage, or impact with the casing; the blade root position can include the coordinates corresponding to the blade tip, such as (0,0); the blade tip deviation angle can be... The leaf root deviation angle can be This reduces flow loss while avoiding localized stress concentration.

[0043] For example, the reference direction from the leaf root to the leaf tip can be a straight line pointing from the leaf root to the leaf tip. The leaf tip deviation angle can include the angle by which the leaf tip position deviates to the left or right relative to the reference direction; the leaf root deviation angle can include the angle by which the leaf root position deviates to the left or right relative to the reference direction.

[0044] In operation S120, a first reference line and a second reference line are constructed based on the shape constraint parameters.

[0045] For example, the first reference line may include a line drawn from the leaf tip to the plane containing the leaf root, and the second reference line may include a line drawn from the leaf root to the plane containing the leaf tip.

[0046] In operation S130, the design shape of the blade is determined based on the first positional deviation of the first intersection point of the first reference line and the plane where the blade root is located relative to the first positional deviation of the blade root, and the second positional deviation of the second intersection point of the second reference line and the plane where the blade tip is located relative to the second positional deviation of the blade tip.

[0047] For example, the first position deviation can represent the degree of offset of the intersection point of the first reference line and the leaf root plane relative to the leaf root position on the plane; the second position deviation can represent the degree of offset of the second intersection point of the second reference line and the plane where the leaf tip position is located relative to the leaf tip position.

[0048] In operation S140, the positions of multiple control points matching the design shape are determined based on the third intersection point.

[0049] For example, the blade can have various design shapes, and the control point calculations, offset directions, and bending patterns differ for different design shapes. For instance, the design shape can include "S-shaped" and "C-shaped" shapes. An "S-shaped" blade can include a blade stacking line that bends to one side and then to the other, with the blade root deviating in the opposite direction to the blade tip, forming a reverse bend. A "C-shaped" blade can include a curve that remains constant from the blade root to the blade tip, forming a "C" shaped arc, with the blade root and blade tip deviating in the same direction.

[0050] For example, an "S-shaped" shape can correspond to an S-shaped stacking line, a "C-shaped" shape can correspond to a C-shaped stacking line, and control points can include reference points used to generate blade stacking lines.

[0051] In operation S150, design parameters for the compressor blades are determined based on multiple control points.

[0052] For example, design parameters may include parameters for determining blade tilt and curvature.

[0053] According to embodiments of this application, a first reference line and a second reference line are constructed based on shape constraint parameters; the design shape of the blade is determined based on the first position deviation of the first intersection point of the first reference line and the plane where the blade root is located relative to the blade root position, and the second position deviation of the second intersection point of the second reference line and the plane where the blade tip is located relative to the blade tip position; the positions of multiple design reference points matching the design shape are determined based on the third intersection point of the first and second reference lines; and the design parameters for designing the compressor blade are determined based on the multiple design reference points. This allows for higher degrees of freedom of variation with fewer reference parameters (such as blade tip position, blade position, blade tip deviation angle, and blade root deviation angle), and supports simultaneous adjustment of bending and sweep. It can also halve the optimization design cycle, simultaneously cover various blade types such as axial compressor rotors, fans, and centrifugal impeller guide vanes, broadening the range of applicable blade types; it is applicable from subsonic to transonic speeds, and from low load to high load, thus broadening the range of applicable operating conditions; and it can be directly transplanted from light aero engines, industrial gas turbines, and marine gas turbines, broadening the applicable engine platforms.

[0054] According to an embodiment of this application, the blade root position includes the position of the center of gravity of the end section of the blade located on the compressor disk side, and the blade tip position includes the position of the center of gravity of the end section of the blade located away from the compressor disk side.

[0055] For example, a disk may be installed in the compressor to support and fix the blades; for instance, the root of the blade may be fitted and fixed to the disk.

[0056] For example, the root section where the blade contacts the compressor disk can be determined to obtain the end section located on the compressor disk side. The coordinates of the centroid of this root section can be used as the blade root position.

[0057] For example, the section containing the blade tip furthest from the compressor disk can be determined, thus obtaining the end section of the blade on the side furthest from the compressor disk, i.e., the cross section of the blade tip. The coordinates of the centroid of this end section can be used as the blade tip position.

[0058] According to an embodiment of this application, constructing a first reference line based on shape constraint parameters includes: determining a reference angle relative to the horizontal direction of the line connecting the leaf root to the leaf tip based on the leaf tip position and the leaf root position; determining the sum of the reference angle and the leaf tip deviation angle to obtain a first direction angle; and constructing a ray along the first direction angle with the leaf root position as the starting point to obtain the first reference line.

[0059] For example, the reference angle of the line connecting the leaf root to the leaf tip relative to the horizontal direction can be calculated as shown in formula (1).

[0060]

[0061] in, The reference angle is ph. The leaf root position can be taken as the origin, and its coordinates can be defined as (0,0). The coordinates corresponding to the leaf tip position P0 are defined as... .

[0062] like Figure 2 As shown, the direction angle of the ray can be determined based on the reference angle.

[0063] For example, the first direction angle can be calculated as shown in formula (2).

[0064] (2)

[0065] in, The first direction angle, For the leaf tip deflection angle, The meaning is explained above and will not be repeated here.

[0066] For example, the leaf tip position can be used as the starting point, that is, as the endpoint of the first reference line, and extended along the first direction angle to form a ray to obtain the first reference line (for example, it can be represented as ray L1).

[0067] According to an embodiment of this application, constructing a second reference line based on shape constraint parameters includes: obtaining a second direction angle based on the sum of a reference angle and a leaf root deviation angle; and constructing a ray along the second direction angle with the leaf root position as the starting point to obtain the second reference line.

[0068] For example, the second direction angle can be calculated as shown in formula (3).

[0069] (3)

[0070] in, β1 is the first direction angle, and β2 is the tip deviation angle. The meaning is explained above and will not be repeated here.

[0071] For example, the leaf root position can be used as the starting point, that is, as the endpoint of the second reference line, and extended along the second direction angle to form a ray, thus obtaining the second reference line (for example, it can be represented as ray L2).

[0072] According to an embodiment of this application, determining the design shape of a blade based on a first positional deviation of the first intersection point of the first reference line and the plane where the blade root is located relative to the blade root position, and a second positional deviation of the second intersection point of the second reference line and the plane where the blade tip is located relative to the blade tip position, includes: when the product of the first positional deviation and the second positional deviation is less than a preset value, the design shape is determined to be a first shape, wherein the first shape indicates that the blade root and the blade tip are bent in opposite directions; when the product of the first positional deviation and the second positional deviation is greater than or equal to the preset value, the design shape is determined to be a second shape, wherein the second shape includes: the blade root and the blade tip are bent in the same direction.

[0073] like Figure 2 As shown, the first intersection point of the first reference line and the plane where the leaf root is located can be determined, and the second intersection point of the second reference line and the plane where the leaf tip is located can be determined.

[0074] For example, the first intersection point of the first reference line and the plane where the leaf root is located (the plane y=0) can be represented as P2, and the second reference line and the plane where the leaf tip is located (the plane...) can be represented as P2. The second intersection point of ) is denoted as P3.

[0075] The first position deviation can be calculated as shown in formula (4).

[0076] (4)

[0077] in, P2x is the x-axis coordinate of the first intersection point P2, and Phx is the x-axis coordinate of the leaf root position Ph.

[0078] The second position deviation can be calculated as shown in formula (5).

[0079] (5)

[0080] in, P3x is the x-axis coordinate of the second intersection point P3, and P0x is the x-axis coordinate of the blade tip position P0.

[0081] For example, the default value can be 0.

[0082] like Figure 2 As shown, in When the value is less than 0, the design shape can be determined as the first shape, that is, the leaf root and the leaf tip are bent in opposite directions. The first shape is, for example, an "S" shape.

[0083] exist When the value is equal to or greater than 0, the design shape can be determined as the second shape, that is, the leaf root and leaf tip are bent in the same direction. The second shape is, for example, a "C" shape.

[0084] According to an embodiment of this application, when the preset shape includes a first shape, determining the positions of multiple control points corresponding to the shape to be set according to the third intersection point includes: determining a first position of the foot of the perpendicular from the third intersection point to the plane where the leaf root is located, and a second position of the foot of the perpendicular from the third intersection point to the plane where the leaf tip is located; and determining the positions of multiple control points corresponding to the first shape according to the first position, the second position, the leaf tip position, and the leaf root position.

[0085] Figure 3 A schematic diagram of a design reference point corresponding to a first shape according to an embodiment of this application is shown.

[0086] like Figure 2 and Figure 3 As shown, for the first shape, the line segments with endpoints P0 and Ph, and the line segments with endpoints P2 and P3 can be determined, and the intersection of the two line segments can be determined to obtain the third intersection point P1.

[0087] For the first shape (such as an "S" shape), the foot of the perpendicular from the third intersection point P1 to the plane containing the leaf tip, P4, and the foot of the perpendicular from the third intersection point P1 to the plane containing the leaf root, P5, can be determined. The first position can include the coordinates of P4, and the second position can include the coordinates of P5.

[0088] For example, an S-shaped blade can correspond to an S-shaped accumulation line. Multiple control points of the S-shaped accumulation line can include P0, P0s, P2s, and Ph, and their calculation methods are shown in formulas (6) to (9).

[0089] P0 = P0 (6)

[0090] (7)

[0091] (8)

[0092] Ph = Ph(9)

[0093] According to an embodiment of this application, determining multiple control points corresponding to a first shape based on a first position, a second position, a leaf tip position, and a leaf root position includes: determining the position of a first intermediate control point relative to the leaf root position and the first position between the leaf root position and the first position based on a preset first parameter; and determining the position of a second intermediate control point relative to the leaf tip position and the second position between the leaf tip position and the second position based on a preset second parameter; wherein the values ​​of the first parameter and the second parameter are between 0 and 1.

[0094] For example, the first intermediate control point can be P2s as shown in formula (8), and the second intermediate control point can be P0s as shown in formula (7).

[0095] The first parameter can be s1 as shown in formula (8), and the second parameter can be s2 as shown in formula (7).

[0096] For example, the offset distance of the intermediate control point can be adjusted by changing the values ​​of the first and second parameters. The values ​​of the first and second parameters can be set between 0 and 1.

[0097] By limiting the values ​​of the first and second parameters to the range of 0 to 1, it can be ensured that the control points fall within the convex hull / segment of the endpoint connection, thereby avoiding numerical problems such as curve reversal, sudden changes in local curvature, or non-monotonicity of x(t) caused by extrapolation. Constraining the first and second parameters and the perpendicular foot parameter to [0,1] is equivalent to limiting the interpolation generation of control points within the endpoint interval, which can significantly reduce the probability of geometric singularities and root-finding failures, and improve the stability of the algorithm in batch optimization scenarios.

[0098] According to an embodiment of this application, when the preset shape includes a second shape, determining multiple control points corresponding to the shape to be set based on the third intersection point includes: determining multiple control points corresponding to the second shape based on the leaf root position, the third intersection point, and the leaf tip position.

[0099] Figure 4 A schematic diagram of a design reference point corresponding to the second shape according to an embodiment of this application is shown.

[0100] like Figure 2 and Figure 4 As shown, for the second shape (such as the "C" shape), it can correspond to the C-shaped overlapping line. The line segment with endpoints P3 and Ph, and the line segment with endpoints P2 and P0 can be determined, and the intersection point of the above two line segments can be determined to obtain the third intersection point P1.

[0101] For the second shape, the third intersection point P1 can be used directly as the intermediate control variable. The multiple control points corresponding to the second shape can include P0, P0s, P2s, and Ph. Their calculation formulas are shown in formulas (10) to (13).

[0102] P0 = P0(10)

[0103] (11)

[0104] (12)

[0105] Ph = Ph (13)

[0106] The meanings of the parameters in formulas (10) to (13) are explained above and will not be repeated here.

[0107] According to the embodiments of this application, a first reference line and a second reference line are constructed based on shape constraint parameters; the design shape of the blade is determined based on the first position deviation of the first intersection point of the first reference line and the plane where the blade root is located relative to the first position of the blade root, and the second position deviation of the second intersection point of the second reference line and the plane where the blade tip is located relative to the second position of the blade tip; multiple control points matching the design shape are determined based on the third intersection point of the first reference line and the second reference line, and the position of the first intermediate control point relative to the blade root and the first position is determined based on the preset first parameter; the position of the second intermediate control point relative to the blade tip and the second position is determined based on the preset second parameter. The design parameters of the blade can be determined based on only five preset control parameters: blade tip position, blade root position, blade tip deviation angle, blade root deviation angle, first parameter, and second parameter. A balance is achieved between the "number of control parameters" and the "degrees of freedom of shape". Sufficient geometric freedom can be obtained simultaneously in the two dimensions of "bending" and "sweeping", and efficiency and surge margin are further improved without sacrificing the boost ratio and structural strength.

[0108] For example, using only five preset control parameters—tip position, root position, tip deviation angle, root deviation angle, first parameter, and second parameter—the "S / C" shaped sweep can be achieved, which traditionally requires 10-20 cross-sections to represent, thus achieving a high degree of geometric freedom. Furthermore, in the first-stage prototype of the high-pressure compressor, the highest isentropic efficiency is increased by 7.12%, and the average efficiency under all operating conditions is increased by 2.8%, improving aerodynamic efficiency. The maximum single-stage pressure ratio can be increased by 1.8%, improving the pressure ratio and providing margin for multi-stage high-pressure ratio design. The stall margin is increased by approximately 5.96%, significantly widening the stable operating range and improving surge margin. With the Bézier curve convexity ensuring curvature continuity, the maximum static stress decreases by 5–8%, and fatigue life increases by 12%, thereby improving structural strength margin. Moreover, the dimensionality of control points is significantly reduced; for example, the number of variables is reduced from at least 20 in related methods to 4, exponentially shrinking the search space. By parameterizing both sweep and swirl simultaneously, the number of iterations in the closed-loop analysis is reduced, resulting in faster iteration convergence.

[0109] For example, the performance of the blade corresponding to the design parameter can be determined. If the blade performance does not meet the predetermined requirements, the values ​​of the blade root position, blade tip position, blade tip deviation angle and blade root deviation angle, the first parameter and the second parameter can be adjusted so that the design parameter can be re-determined based on the adjusted values. The final design parameter can be determined by iteratively adjusting the values ​​of the blade root position, blade tip position, blade tip deviation angle and blade root deviation angle, the first parameter and the second parameter.

[0110] According to an embodiment of this application, determining the design parameters of a blade based on multiple controls includes: generating a Bézier curve based on the multiple controls; using the Bézier curve as the stacking line of the blade, and determining the design parameters of the blade based on the stacking line; wherein the design parameters include at least the degree of curvature and the degree of tilt of the blade.

[0111] Figure 5 A schematic diagram of a sweeping overlay parameter scan according to an embodiment of this application is shown.

[0112] A Bézier curve can be, for example, a cubic Bézier curve. A cubic Bézier curve can be represented by formula (14).

[0113] (14)

[0114] in, It is a cubic Bézier curve. These are third-order Bernstein basis functions, where t is a parameter. .

[0115] For example, t can be obtained from x by the bisection method. For instance, since Bézier curves can be written in parametric form... When the selected control point satisfies x(t) in When the upper axis is monotonic, given the target axis coordinates By solving the equation The corresponding parameter t is obtained. An initial value interval of [0,1] can be chosen, and the endpoints of the interval are iteratively updated until... Or it may reach the maximum number of iterations.

[0116] For example, the degree of curvature of the blade can be expressed as the "bend" of the blade, and the degree of tilt of the blade can be expressed as the "swish" offset of the blade.

[0117] For example, when s1 or s2 is 0, that is, when it degenerates into a quadratic Bézier curve, the sweep offset It can be calculated using formula (15).

[0118]

[0119] For example, in That is, in the case of a cubic Bézier curve, the sweep offset It can be calculated using formula (16).

[0120]

[0121] According to embodiments of this disclosure, by using low-order Bézier curves as blade stacking lines and combining them with five control parameters, the two three-dimensional features of the blade, sweep and bending, can be described simultaneously, significantly reducing design variables while ensuring curvature continuity.

[0122] For example, the cubic Bézier curve can be upgraded to a fourth or fifth order Bézier curve according to actual needs, or a B-spline curve or a non-uniform rational B-spline curve (NURBS) can be used; the bisection method can also be replaced with the Newton-Raphson method or an analytical root-finding method according to actual needs.

[0123] For example, when the order of a curve is increased to fourth or fifth order Bézier curves, the number of control points can be increased accordingly. For instance, a fourth-order Bézier curve has 5 control points, and a fifth-order Bézier curve has 6. The newly added control points can be arranged on the line connecting the endpoints and intermediate points according to the first and second parameters, or introduced as additional shape degrees of freedom to adjust the positions of intermediate control points using the third and fourth parameters. Correspondingly, the curve evaluation formula can be replaced with an nth-order Bernstein basis function summation form.

[0124] When the curve type is changed to B-spline / NURBS, the control points of the Bézier curve can be replaced with spline control points, node vectors and weights. Correspondingly, the inverse parametric equation can be changed from the Bézier form of x(t) to the spline form.

[0125] According to the embodiments of this application, when the first reference line is parallel to the second reference line, a preset point can be used as the third intersection point; when the first reference line coincides with the second reference line, the midpoint between the leaf root position and the leaf tip position can be used as the third intersection point.

[0126] Figure 6 A schematic diagram illustrating a compressor blade design method according to an embodiment of this application is shown. Figure 6 As shown, for the three-dimensional design of the composite swept rotor blade of the gas turbine compressor based on Bézier curves, numerical robustness measures can be taken after inputting parameters (such as the first parameter, the second parameter, the blade tip position, the blade root position, the blade tip deviation angle, and the blade root deviation angle), going through geometric construction steps (such as determining the blade shape), and performing curve evaluation (such as after Bézier curve evaluation).

[0127] For example, the angle between the first reference line and the second reference line can be determined. , can When the first reference line is determined to be parallel to the second reference line, the predetermined extreme intersection point (i.e., the preset point) can be used as the third intersection point. The preset point can be, for example, the extreme vertical intersection point, the extreme horizontal intersection point, etc., or the midpoint of the line connecting the leaf root position and the leaf tip position.

[0128] For example, it can also be a determinant of two straight lines between the first reference line and the second reference line. In this case, determine a reference line that coincides with or is parallel to the second reference line. In this case, the midpoint between the leaf root position and the leaf tip position can be used as the third intersection point.

[0129] According to the embodiments of this application, when the first reference line is parallel to the second reference line, a preset point is used as the third intersection point; when the first reference line coincides with the second reference line, the midpoint between the leaf root position and the leaf tip position is used as the third intersection point. The values ​​of the first parameter and the second parameter are 0 to 1, which can ensure the robustness of the control parameters. There are fallback strategies for extreme cases such as singular slopes, parallel lines, and determinants close to zero. This can ensure the continuity of control point generation and the stability of the algorithm, and guarantee the long-term stable operation of the engineering software.

[0130] The embodiments of this application have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of this application. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Without departing from the scope of this application, those skilled in the art can make various substitutions and modifications, all of which should fall within the scope of this application.

Claims

1. A method for designing compressor blades, characterized in that, The method includes: Obtain shape constraint parameters for designing compressor blades. The shape constraint parameters include: blade tip position, blade root position, blade tip deviation angle, and blade root deviation angle. The blade tip deviation angle includes the deflection angle of the blade tip position relative to the reference direction from the blade root to the blade tip, and the blade root deviation angle includes the deflection angle of the blade root position relative to the reference direction. Construct a first reference line and a second reference line based on the shape constraint parameters; The design shape of the blade is determined based on the first position deviation of the first intersection point of the first reference line and the plane where the leaf root is located relative to the leaf root position, and the second position deviation of the second intersection point of the second reference line and the plane where the leaf tip is located relative to the leaf tip position. Based on the third intersection point, determine multiple control points that match the design shape; Based on the multiple control points, the design parameters for designing the compressor blades are determined.

2. The method according to claim 1, characterized in that, The blade root position includes the position of the center of gravity of the end section of the blade located on the compressor disk side, and the blade tip position includes the position of the center of gravity of the end section of the blade located away from the compressor disk side.

3. The method according to claim 1, characterized in that, The step of constructing the first reference line based on the shape constraint parameters includes: Based on the leaf tip position and the leaf root position, determine the reference angle of the line connecting the leaf root to the leaf tip relative to the horizontal direction; The first direction angle is obtained by summing the reference angle and the blade tip deviation angle. Using the blade tip position as the starting point, a ray is constructed along the first direction angle to obtain the first reference line.

4. The method according to claim 3, characterized in that, The step of constructing the second reference line based on the shape constraint parameters includes: The second direction angle is obtained by summing the reference angle and the leaf root deviation angle; Using the leaf root position as the starting point, a ray is constructed along the second direction angle to obtain the second reference line.

5. The method according to claim 1, characterized in that, The step of determining the design shape of the blade based on the first positional deviation of the first intersection point of the first reference line and the plane where the leaf root is located relative to the leaf root position, and the second positional deviation of the second intersection point of the second reference line and the plane where the leaf tip is located relative to the leaf tip position, includes: When the product of the first position deviation and the second position deviation is less than a preset value, the design shape is determined to be a first shape, wherein the first shape indicates that the leaf root and the leaf tip of the leaf are bent in opposite directions; When the product of the first position deviation and the second position deviation is greater than or equal to a preset value, the design shape is determined to be a second shape, wherein the second shape includes: the leaf root and the leaf tip of the blade are bent in the same direction.

6. The method according to claim 5, characterized in that, When the preset shape includes the first shape, determining the multiple control points corresponding to the intended shape based on the third intersection point includes: Determine the first position of the perpendicular foot of the third intersection point to the plane where the leaf root is located, and the second position of the perpendicular foot of the third intersection point to the plane where the leaf tip is located; Based on the first position, the second position, the leaf tip position, and the leaf root position, the plurality of control points corresponding to the first shape are determined.

7. The method according to claim 6, characterized in that, The step of determining the plurality of control points corresponding to the first shape based on the first position, the second position, the leaf tip position, and the leaf root position includes: Based on a preset first parameter, the position of a first intermediate control point relative to the leaf root position and the first position is determined between the leaf root position and the first position; Based on a preset second parameter, the position of a second intermediate control point relative to the blade tip position and the second position is determined between the blade tip position and the second position; wherein the values ​​of the first parameter and the second parameter are between 0 and 1.

8. The method according to claim 5, characterized in that, When the preset shape includes the second shape, determining the multiple control points corresponding to the intended shape based on the third intersection point includes: Based on the leaf root position, the third intersection point, and the leaf tip position, the plurality of control points corresponding to the second shape are determined.

9. The method according to claim 1, characterized in that, Determining the design parameters of the blade based on the multiple controls includes: Based on the aforementioned multiple controls, a Bézier curve is generated; The Bézier curve is used as the stacking line of the blade, and the design parameters of the blade are determined based on the stacking line. The design parameters include at least the degree of bending and the degree of tilt of the blade.

10. The method according to claim 1, characterized in that, The method further includes: When the first reference line is parallel to the second reference line, the preset point is taken as the third intersection point; When the first reference line coincides with the second reference line, the midpoint between the leaf root position and the leaf tip position is taken as the third intersection point.

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