Axial flow fan blade design method and device and storage medium

Abstract

The application provides a kind of axial flow fan blade design method, device and storage medium, the axial flow fan blade design method includes the following steps: S1: selecting basic airfoil, obtaining camber line characteristic point and airfoil characteristics, obtaining skeleton line parameters;S2: setting new camber line, the combination of new camber line and skeleton line parameters realizes two-dimensional airfoil transformation;S3: the multiple airfoils of two-dimensional airfoil transformation are wrapped in different diameter cylindrical surface, the angle of bending angle ω and rake angle γ is adjusted, and new three-dimensional airfoil transformation is carried out.The axial flow fan blade design method provided by the application can maintain most of the characteristics of the basic airfoil during the airfoil transformation process by designing a feasible airfoil transformation method, simplifies the modeling and design process of the axial flow fan blade, greatly improves the blade airfoil design efficiency, can realize flexible modification of blade parameters, and studies the influence of outlet angle and curvature on fan blade performance by combining CFD simulation.

Description

Technical Field

[0001] This invention relates to the field of air conditioning equipment technology, and more specifically, to an axial flow fan blade design method, device, and storage medium. Background Technology

[0002] In recent years, competition in the air conditioning market has become increasingly fierce. Air conditioning manufacturers have made adjustments based on market demand and developed targeted air conditioning products, resulting in short development cycles and heavy workloads for new air conditioning products. As a core component of the outdoor unit of an air conditioner, the axial fan blade has a significant impact on the overall performance of the air conditioner.

[0003] The complex curved surface of axial flow wind turbine blades presents challenges in modeling, resulting in a lack of accuracy in the modeled blades. The conventional design method involves manually modifying individual airfoils in CAD software based on simulation or experimental results, and then arranging the airfoils radially according to design requirements. However, this method suffers from poor repeatability, slight variations in adjustments made by different designers for the same parameter, and low efficiency. Summary of the Invention

[0004] The purpose of this invention is to propose an axial flow fan blade design method that allows for flexible modification of blade parameters (chord length, installation angle, inlet angle, outlet angle, camber, and thickness). The invention also incorporates CFD simulation to study the impact of outlet angle and camber on fan blade performance, thereby solving the problems of poor repeatability and low efficiency in existing axial flow fan blade designs.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] An axial flow fan blade design method includes the following steps:

[0007] S1: Select the basic airfoil, obtain the mid-curve feature points and airfoil characteristics, and obtain the skeleton line parameters;

[0008] S2: Set a new mid-curve line, and combine the new mid-curve line with the skeleton line parameters to achieve two-dimensional airfoil transformation;

[0009] S3: Wrap multiple airfoils after two-dimensional airfoil transformation around cylindrical surfaces of different diameters, and perform new three-dimensional airfoil transformation by adjusting the bend angle ω and sweep angle γ.

[0010] The axial flow wind turbine design method described in this invention can shorten the design time of wind turbine airfoils, retain the characteristics of the original airfoil to the maximum extent during the airfoil transformation process, and is simple to operate with high repeatability.

[0011] Furthermore, step S1 includes the following steps:

[0012] S11: Based on the selected base airfoil, obtain the parameters of the base airfoil, including: airfoil inlet angle α, airfoil outlet angle β, installation angle θ, and turn angle θ. c , radius r of the tangent circle, maximum curvature f, chord length L;

[0013] S12: Draw inscribed circles based on the upper and lower arcs of the basic airfoil. The center of the inscribed circle is called the mid-arc feature point. The center of each inscribed circle is called the mid-arc feature point M2. The point of tangency between the inscribed circle and the upper arc of the basic airfoil is called the upper arc feature point M1. The point of tangency between the inscribed circle and the lower arc of the basic airfoil is called the lower arc feature point M3.

[0014] S13: Connect the middle arc feature points M2 in sequence to obtain the middle arc of the airfoil. Connect the corresponding upper arc feature points M1, middle arc feature points M2, and lower arc feature points M3 to obtain the feature point connection line. The middle arc line and the feature point connection line form the skeleton line of the basic airfoil.

[0015] S14: Analyze and obtain the skeleton line parameters that preserve the airfoil characteristics.

[0016] The axial flow wind turbine design method described in this application obtains the skeleton line parameter information by analyzing the skeleton line of the selected basic airfoil, thereby preserving the original airfoil characteristics during two-dimensional airfoil transformation and ensuring the accuracy and reliability of blade adjustment during the design and simulation analysis of the axial flow wind turbine.

[0017] Furthermore, in step S14, the skeleton line is analyzed separately, and the angle Φ between the tangent line containing the feature point of the middle arc and the line connecting the feature point of the middle arc and the upper and lower arcs is calculated, as well as the relative position S of the feature point of the middle arc on the middle arc. K / S N (k=2,3……n), the distance r between the feature point of the middle arc and the line connecting the upper and lower arcs is used as the skeleton line parameter.

[0018] The skeleton line parameters analyzed above can retain most of the characteristics of the original basic airfoil.

[0019] Furthermore, in step S2, a new center arc is set, which includes the following parameters:

[0020] New entrance angle α new New exit angle β new New installation angle θ new New curvature f new and the new curvature position L f New chord length L new .

[0021] This setup enables rapid implementation of the new central arc structure design and allows for quick fine-tuning of the structure as needed, further improving the efficiency of axial flow fan blade design.

[0022] Furthermore, based on the established new central arc, step S2 also includes the following steps:

[0023] S21: Based on the relative positions of the feature points on the middle arc line S K / S N (k = 2, 3, ..., n) Determine the position of the characteristic point of the middle arc on the new middle arc;

[0024] S22: Determine the tangent line where the feature point of the middle arc is located, and then keep the included angle Φ constant, adjust the airfoil thickness by changing r;

[0025] S23: Determine the upper and lower arc feature points of the new airfoil, and finally smoothly connect all feature points to obtain the new airfoil, completing the two-dimensional airfoil transformation.

[0026] This setting can quickly generate a target airfoil suitable for axial flow blades by changing design parameters. Through a reasonable two-dimensional airfoil transformation, the chord length, installation angle, exit angle, inlet angle, camber, camber position, and thickness of the airfoil can be reliably changed.

[0027] Furthermore, in step S3, the new airfoil structures resulting from the transformation of multiple two-dimensional airfoils in steps S1 and S2 are wrapped around cylindrical surfaces of varying diameters, with the leading edge of the blade as a reference. By adjusting the bend angle ω and sweep angle γ, the blades exhibit different bend and sweep shapes in three-dimensional space. s For each airfoil, the initial angle on the corresponding cylindrical surface is δ. e To determine the termination angle, after determining the coordinates of the leading edge point in three dimensions, the two-dimensional airfoil is "wrapped" on the corresponding cylindrical surface to form a spatial curve, thus completing the three-dimensional transformation of the airfoil.

[0028] This setup controls the bending and sweeping shape of the blades in three-dimensional space by controlling the leading edge point, and can be combined with CFD simulation to study the effects of exit angle and camber on blade performance.

[0029] A second objective of this invention is to provide an axial flow fan blade design device, comprising a processor and a memory, wherein the memory is used to store a computer program, the computer program comprising program instructions for an axial flow fan blade design method, and the processor is used to execute the axial flow fan blade design method as described above.

[0030] A third objective of this invention is to provide a computer-readable storage medium storing a computer program that is read and executed by a processor to implement the axial flow fan blade design method described above.

[0031] Compared with the prior art, the axial flow fan blade design method, device and storage medium of the present invention have the following beneficial effects:

[0032] The axial flow wind turbine design method, device, and storage medium described in this invention, through the design of a practical airfoil transformation method, can still maintain most of the characteristics of the basic airfoil during the airfoil transformation process, simplifying the modeling and design process of axial flow wind turbines, greatly improving the efficiency of blade airfoil design, and enabling flexible modification of blade parameters (chord length, installation angle, inlet angle, outlet angle, camber, and thickness). Furthermore, the influence of outlet angle and camber on wind turbine performance was studied using CFD simulation. Attached Figure Description

[0033] Figure 1 This is a logical schematic diagram of the axial flow fan blade design method described in an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the basic airfoil parameters of the axial flow wind turbine according to an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the basic airfoil of the axial flow wind turbine according to an embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of the airfoil skeleton line parameter structure of the axial flow wind turbine according to an embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of the new arc structure described in an embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram of the two-dimensional airfoil transformation structure of the axial flow wind turbine according to an embodiment of the present invention;

[0039] Figure 7 This is a schematic diagram of the three-dimensional airfoil transformation structure of the axial flow wind turbine according to an embodiment of the present invention;

[0040] Figure 8 This is a schematic diagram of the three-dimensional airfoil of the axial flow fan blade according to an embodiment of the present invention;

[0041] Figure 9 This is a flowchart illustrating the axial flow fan blade design according to an embodiment of the present invention.

[0042] Figure 10 A data diagram showing the influence of curvature / outlet angle on airflow in the axial flow fan design described in this embodiment of the invention. Detailed Implementation

[0043] It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other. The descriptions of "first," "second," etc., mentioned in the embodiments of the present invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0044] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0045] Example 1

[0046] like Figures 1-9 As shown, this invention discloses an axial flow fan blade design method, including the following steps:

[0047] S1: Select the basic airfoil, obtain the mid-curve feature points and airfoil characteristics, and obtain the skeleton line parameters;

[0048] S2: Set a new mid-curve line, and combine the new mid-curve line with the skeleton line parameters to achieve two-dimensional airfoil transformation;

[0049] S3: Wrap multiple airfoils after two-dimensional airfoil transformation around cylindrical surfaces of different diameters, and perform new three-dimensional airfoil transformation by adjusting the bend angle ω and sweep angle γ.

[0050] The axial flow wind turbine blade design method disclosed in this invention first selects a suitable two-dimensional planar airfoil as the basic airfoil. The skeleton line parameters of the basic airfoil are obtained by analyzing the basic airfoil. Based on the original mid-curve, a new mid-curve parameter is given. The chord length, thickness, installation angle, inlet angle, outlet angle, and camber are changed by using two-dimensional airfoil transformation to generate a new two-dimensional airfoil. Finally, the airfoil structure transformed from the two-dimensional airfoil is wrapped around cylindrical surfaces of different diameters to perform three-dimensional airfoil transformation. By adjusting the camber angle ω (the angle between the innermost leading edge point and the center of the cylindrical surface and the outermost leading edge point and the center of the cylindrical surface) and the sweep angle γ, the blade can be made to exhibit different camber and sweep shapes in three-dimensional space to complete the three-dimensional transformation.

[0051] The axial flow wind turbine design method described in this invention can shorten the design time of wind turbine airfoils, retain the characteristics of the original airfoil to the maximum extent during the airfoil transformation process, and is simple to operate.

[0052] As a preferred example of the present invention, step S1 includes the following steps:

[0053] S11: Based on the selected base airfoil, obtain the parameters of the base airfoil, including: airfoil inlet angle α, airfoil outlet angle β, installation angle θ, and turn angle θ. c , radius r of the tangent circle, maximum curvature f, chord length L;

[0054] S12: Draw inscribed circles based on the upper and lower arcs of the basic airfoil. The center of the inscribed circle is called the mid-arc feature point. The center of each inscribed circle is called the mid-arc feature point M2. The point of tangency between the inscribed circle and the upper arc of the basic airfoil is called the upper arc feature point M1. The point of tangency between the inscribed circle and the lower arc of the basic airfoil is called the lower arc feature point M3.

[0055] S13: Connect the middle arc feature points M2 in sequence to obtain the middle arc of the airfoil. Connect the corresponding upper arc feature points M1, middle arc feature points M2, and lower arc feature points M3 to obtain the feature point connection line. The middle arc line and the feature point connection line form the skeleton line of the basic airfoil.

[0056] S14: Analyze and obtain the skeleton line parameters that preserve the airfoil characteristics.

[0057] The axial flow wind turbine design method described in this application obtains the skeleton line parameter information by analyzing the skeleton line of the selected basic airfoil, thereby preserving the original airfoil characteristics during two-dimensional airfoil transformation and ensuring the accuracy and reliability of blade adjustment during the design and simulation analysis of the axial flow wind turbine.

[0058] like Figure 2 As shown, a is the basic airfoil structure selected in S11; b is the airfoil's middle arc obtained by drawing an inscribed circle between the upper and lower arcs of the basic airfoil in S12 and sequentially connecting the middle arc feature points M2, and connecting the corresponding upper arc feature points M1, middle arc feature points M2, and lower arc feature points M3; c is a schematic diagram of the extracted skeleton line structure.

[0059] As a preferred example of the present invention, in step S14, the skeleton line is analyzed separately, and the angle Φ between the tangent line where the feature point of the middle arc line is located and the line connecting the feature point of the middle arc line and the upper arc line and the lower arc line is calculated, as well as the relative position S of the feature point of the middle arc line on the middle arc line. K / S N (k=2,3……n), the distance r (inscribed circle radius) between the feature points of the middle arc and the lines connecting the upper and lower arcs is used as the skeleton line parameter.

[0060] The angle Φ between the tangent line containing the feature point of the middle arc and the line connecting the feature point of the middle arc to the upper and lower arcs is calculated through analysis; the relative position S of the feature point of the middle arc on the middle arc is also determined. K / S NThe distance *r* between the feature points of the middle arc and the lines connecting the upper and lower arcs serves as the basis for airfoil transformation, preserving most of the original airfoil's features. Therefore, these three parameters are used as skeleton line parameters, such as... Figure 4 As shown, the angles between the tangent of the first feature point and the lines connecting the middle arc feature point and the upper and lower arcs are Φ1 and Φ2, respectively. The distance between the first feature point and the lines connecting the upper and lower arcs is r1. The arc length between the first and second feature points is S2, and the arc length between the first and nth feature points is S. n The relative position of the second feature point on the middle arc is S2 / S N The angle Φ between the tangent of other feature points and the lines connecting the upper and lower arcs, and the relative position S of the feature points on the middle arc. K / S N The distance r between the feature point of the middle arc and the line connecting the upper and lower arcs is similar to that described above, and will not be repeated here.

[0061] The skeleton line parameters analyzed above can retain most of the characteristics of the original basic airfoil.

[0062] As a preferred example of the present invention, a new central arc line is defined, and the new central arc line includes the following parameters:

[0063] New entrance angle α new New exit angle β new New installation angle θ new New curvature f new and the new curvature position L f New chord length L new .

[0064] As a specific example of the present invention, when performing basic airfoil transformation, the new mid-curve adopts a two-segment arc form, that is, the mid-curve is composed of two spline curves, where A / A'(0,0) is the leading edge point, and C(X) is the leading edge point. C1 Y C1 L is the trailing edge point. new Let B(X) be the chord length of the middle arc. B1 Y B1 ( ) is the common point of the two arcs. Determine the new installation angle θ. new Rotate around point A with the front edge as the center of rotation:

[0065]

[0066] Obtain the rotated C'(X) C2 Y C2 Point coordinates, given curvature f new and curvature position L f Determine B'(X) B1 Y B1), where the tangent at point B' is parallel to AC, given the entrance angle α. new and exit angle β new Determine arcs A'B' and B'C', and construct them as follows: Figure 5 The new central arc is shown.

[0067] Based on the established new central arc, step S2 further includes the following steps:

[0068] S21: Based on the relative positions of the feature points on the middle arc line S K / S N (k = 2, 3, ..., n) Determine the position of the characteristic point of the middle arc on the new middle arc;

[0069] S22: Determine the tangent line where the feature point of the middle arc is located, and then keep the included angle Φ constant, adjust the airfoil thickness by changing r;

[0070] S23: Determine the upper and lower arc feature points of the new airfoil, and finally smoothly connect all feature points to obtain the new airfoil, completing the two-dimensional airfoil transformation.

[0071] like Figure 6 As shown in Figure d, based on the new central arc line combined with the skeleton line parameters, the central arc line feature points, upper arc line feature points, and lower arc line feature points of the new airfoil are determined. The upper arc line feature points and lower arc line feature points are connected sequentially by a smooth curve to form the upper arc line and lower arc line of the new airfoil. The end arc of the new airfoil is an arc tangent to the upper arc line and lower arc line with the central arc line feature point at the end as the center and the adjusted radius r as the radius. Finally, the new airfoil as shown in Figure e is formed.

[0072] As a preferred example of the present invention, in step S3, the new airfoil structures resulting from the multiple two-dimensional airfoil transformations in steps S1 and S2 are wrapped around cylindrical surfaces of varying diameters, with the leading edge of the blade as a reference. By adjusting the bend angle ω and sweep angle γ, the blades exhibit different bend and sweep shapes in three-dimensional space. s For each airfoil, the initial angle on the corresponding cylindrical surface is δ. e To determine the termination angle, after determining the coordinates of the leading edge point in three dimensions, the two-dimensional airfoil is "wrapped" on the corresponding cylindrical surface to form a spatial curve, thus completing the three-dimensional transformation of the airfoil.

[0073] like Figure 7 As shown, three-dimensional airfoil transformation involves arranging multiple two-dimensional airfoils on a spatial cylindrical surface according to certain rules through rotation, translation, and projection operations, so that the wind turbine blades present different bending and sweeping forms. Figure 7 The schematic diagram on the right side shows the projection of a single blade onto the plane of rotation. ω is the bend angle, which is the angle between the innermost leading edge point and the center of the cylinder, and the outermost leading edge point and the center of the cylinder. γ is the sweep angle, and δ... sThe initial angle of each airfoil on the corresponding cylindrical surface affects the position of a single blade on the plane of rotation, δ. e The termination angle can be determined using the chord length L and the installation angle θ. Based on the selected bend angle ω and sweep angle γ, the blades exhibit different bend and sweep shapes in three-dimensional space. Using the set blade leading edge point as a reference, the angle is determined by δ... s Determine the initial position of a single airfoil on the plane of rotation using δ e After determining the endpoint position of a single airfoil on the plane of rotation and the coordinates of the leading edge point in three dimensions, "wrapping" the two-dimensional airfoil onto the corresponding cylindrical surface forms the three-dimensional airfoil transformation space curve, ultimately resulting in a shape like... Figure 8 The three-dimensional airfoil structure shown.

[0074] Specifically, according to the axial flow fan blade design method disclosed in this invention, taking a 2.3P air conditioner outdoor unit as the simulation object, the fan blade diameter is 553mm, the blade height is 126mm, the inlet angle is 5.1°~15.5°, the outlet angle is 31.2°~36.2°, and the installation angle is 18.8°~28.9°. The specific parameters are as follows:

[0075] Table 1 Blade Parameters

[0076]

[0077] The outdoor unit simulation model includes inlet and outlet extension sections, condenser, motor bracket, motor, guide ring, and axial flow fan blades. The outdoor unit model is divided into core meshes using a hexahedron.

[0078] The simulation software used is Fluent. Data exchange between the blade rotation computational domain and the static computational domain is achieved via an interface. Given a rotational speed of 800 r / min, steady-state calculations are performed using the MRF model. Evaporator resistance is simulated using a porous medium, with viscosity and inertia coefficients set in various directions. Due to limited computational resources, the mesh size needs to be moderate. Too many meshes result in long computation times, while too few meshes lead to poor accuracy. Mesh independence checks show that a mesh size ranging from 3.8 million to 9 million results in an error of approximately 1%. Considering both computational accuracy and simulation resources, a simulation mesh size of 7.7 million was selected for the calculations.

[0079] Based on the airfoil transformation method described in this invention, the effects of the outlet angle and camber on the air volume of the external unit were studied by changing the blade camber (×1.1, ×1.2, ×1.3) and the outlet angle (+2, +4, +6).

[0080] Analysis shows that after changing the airfoil to alter the exit angle and camber, the exit angle affects the "camber" of the blade's trailing edge, while the leading edge remains largely unchanged. The camber, however, affects both the leading and trailing edges; a larger exit angle or camber results in a more cambered blade. Experiments have shown that... Figure 10The graph showing the effect of blade curvature / outlet angle on airflow indicates that as the blade outlet angle increases, the airflow gradually increases, but at a relatively slow rate; as the blade curvature increases, the airflow increases significantly. However, since the outlet angle has a relatively small impact on the camber, when a small increase in airflow is needed, only the outlet angle can be increased, which has little impact on noise. When noise is a significant factor and a large increase in airflow is required, the blade curvature can be changed, but the curvature cannot be too large, otherwise it will cause airflow separation on the blade suction surface.

[0081] The axial flow wind turbine design method described in this invention designs a practical airfoil transformation method. The essence of airfoil transformation is to generate a target airfoil suitable for axial flow wind turbines by changing design parameters. During the airfoil transformation process, most of the characteristics of the basic airfoil can still be maintained, which simplifies the modeling and design process of axial flow wind turbines, greatly improves the efficiency of blade airfoil design, and allows for flexible modification of blade parameters (chord length, installation angle, inlet angle, outlet angle, camber, and thickness). The influence of outlet angle and camber on wind turbine performance was studied in conjunction with CFD simulation.

[0082] The following are embodiments of the apparatus of the present invention, which can be used to execute embodiments of the method of the present invention. For details not omitted in the apparatus embodiments, please refer to the embodiments of the method of the present invention.

[0083] In one embodiment of the present invention, an axial flow fan blade design device is provided. This device includes a processor and a memory. The memory stores a computer program, which includes program instructions for an axial flow fan blade design method. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computational and control core of the axial flow fan blade design device, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions to achieve the corresponding method flow or corresponding function. The processor described in this embodiment can be used to execute the operation of the aforementioned axial flow fan blade design method.

[0084] In one embodiment of the present invention, a computer-readable storage medium is also provided. This computer-readable storage medium is a memory device within an axial flow fan blade design apparatus, used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the axial flow fan blade design apparatus and extended storage media supported by the terminal device. The computer-readable storage medium provides storage space containing the terminal's operating system. Furthermore, the storage space also contains an axial flow fan blade design method program suitable for loading and execution by a processor. It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk storage device.

[0085] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for designing axial flow fan blades, characterized in that, For use in air conditioner outdoor units, the following steps are included: S1: Select the basic airfoil, obtain the mid-curve feature points and airfoil characteristics, and obtain the skeleton line parameters; S2: Set a new mid-curve line, and combine the new mid-curve line with the skeleton line parameters to achieve two-dimensional airfoil transformation; S3: Wrap multiple airfoils after two-dimensional airfoil transformation around cylindrical surfaces of different diameters, and perform new three-dimensional airfoil transformation by adjusting the angles of the bend ω and sweep γ; Step S1 includes the following steps: S11: Based on the selected base airfoil, obtain the parameters of the base airfoil, including: airfoil inlet angle α, airfoil outlet angle β, installation angle θ, and turn angle θ. c , radius r of tangent circle, maximum curvature f, chord length L; S12: Draw inscribed circles based on the upper and lower arcs of the basic airfoil. The center of the inscribed circle is called the mid-arc feature point. The center of each inscribed circle is called the mid-arc feature point M2. The point of tangency between the inscribed circle and the upper arc of the basic airfoil is called the upper arc feature point M1. The point of tangency between the inscribed circle and the lower arc of the basic airfoil is called the lower arc feature point M3. S13: Connect the middle arc feature points M2 in sequence to obtain the middle arc of the airfoil. Connect the corresponding upper arc feature points M1, middle arc feature points M2, and lower arc feature points M3 to obtain the feature point connection line. The middle arc line and the feature point connection line form the skeleton line of the basic airfoil. S14: Analyze and obtain the skeleton line parameters that preserve the airfoil characteristics.

2. The axial flow fan blade design method according to claim 1, characterized in that, In step S14, the skeleton line is analyzed separately, and the angle Φ between the tangent line of the middle arc feature point M2 and the line connecting the middle arc feature point M2, the upper arc feature point M1, and the lower arc feature point M3, and the relative position S of the middle arc feature point M2 on the middle arc are calculated. K / S N The radius r of the tangent circle is used as the skeleton line parameter, where K = 2, 3, ..., N.

3. The axial flow fan blade design method according to claim 2, characterized in that, In step S2, a new mid-arc line is set, which includes the following parameters: new entry angle α. new New exit angle β new New installation angle θ new New curvature f new and the new curvature position L f New chord length L new .

4. The axial flow fan blade design method according to claim 3, characterized in that, Based on the established new central arc, step S2 further includes the following steps: S21: Based on the relative position S of the characteristic point M2 on the middle arc line. K / S N Determine the position of the characteristic point M2 of the middle arc on the new middle arc, where K = 2, 3, ..., N; S22: Determine the tangent line of the mid-arc feature point M2, and then keep the included angle Φ constant and adjust the airfoil thickness by changing r; S23: Determine the upper arc feature point M1 and the lower arc feature point M3 of the new airfoil, and finally smoothly connect the feature points to obtain the new airfoil, thus completing the two-dimensional airfoil transformation.

5. The axial flow fan blade design method according to claim 4, characterized in that, In step S3, the new airfoil structures after the transformation of multiple two-dimensional airfoils in steps S1 and S2 are wrapped around cylindrical surfaces of different diameters, with the leading edge of the blade as the reference. By adjusting the bend angle ω and sweep angle γ, the blade presents different bend and sweep shapes in three-dimensional space. After determining the coordinates of the leading edge point in three dimensions, wrapping the two-dimensional airfoil around the corresponding cylindrical surface forms a spatial curve, thereby completing the three-dimensional transformation of the airfoil.

6. An axial flow fan blade design device, characterized in that, The device includes a processor and a memory, the memory being used to store a computer program, the computer program including program instructions for an axial flow fan blade design method, and the processor being used to execute the axial flow fan blade design method as described in any one of claims 1 to 5.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which is read and executed by a processor to implement the axial flow fan blade design method as described in any one of claims 1 to 5.

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