Design method of high-performance straight-blade axial flow fan aerodynamic blade profile

Abstract

The application discloses a design method of a high-performance straight-blade axial flow fan aerodynamic blade profile, belongs to the technical field of axial flow fans, and comprises an axial flow fan blade profile reference scheme, a blade profile automation scheme and a blade profile optimization scheme. Firstly, the axial flow fan blade profile reference scheme is selected, and lift coefficient reference values and drag coefficient reference values are obtained through lift coefficients and drag coefficients under multiple working conditions; secondly, the blade profile automation scheme is used to realize full-flow automation of the blade profile under given input parameters; finally, based on the blade profile optimization scheme, the lift coefficient reference values, the drag coefficient reference values and the blade profile automation scheme are combined, and a large-scale screening and optimization of the axial flow fan is carried out through an optimization algorithm, so that the high-performance straight-blade axial flow fan aerodynamic blade profile is finally determined. The application can reduce the number of control points, improve the efficiency of parameterized modeling while accurately describing the blade profile, greatly improve the calculation efficiency, and adapt the optimized blade profile to more working conditions, so that the high-performance straight-blade axial flow fan aerodynamic blade profile is screened.

Description

Technical Field

[0001] This invention belongs to the field of axial flow fan technology and relates to a design method for the aerodynamic blade profile of a high-performance straight-blade axial flow fan. Background Technology

[0002] The design goal of axial flow fans is to improve efficiency and reduce energy consumption. To reduce energy consumption, fan manufacturers and research institutions are constantly improving the blade design and aerodynamic characteristics of axial flow fans to enhance efficiency. Because straight-blade fans have a natural advantage in manufacturing cost, high-performance straight-blade axial flow fan aerodynamic profiles have been a key research area for fan manufacturers. Axial flow fans have a large outer diameter and a small hub, typically below 0.3 mm. If straight blades are used, the aerodynamic parameters change drastically along the blade height, and the operating conditions of the blade profile vary significantly across multiple blade height sections. Therefore, the blade profile needs to achieve high lift coefficient, low loss coefficient, and excellent performance under varying operating conditions, making blade design quite challenging.

[0003] To address the aforementioned problems, this invention provides a fan blade profile obtained by combining CFD numerical methods with optimization algorithms. This blade profile exhibits high aerodynamic efficiency when applied to axial flow fans with straight blades. Summary of the Invention

[0004] The problem to be solved by the present invention is to address the deficiencies mentioned in the background technology by providing a design method for the aerodynamic blade profile of a high-performance straight-blade axial flow fan. This method uses CFD numerical calculation method combined with optimization algorithm to obtain a fan blade profile with good aerodynamic performance under varying operating conditions, low air resistance, and fast design speed.

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

[0006] A design method for high-performance straight-blade axial flow fan aerodynamic blades is disclosed. The method includes an axial flow fan blade reference scheme, an automated blade scheme, and a blade optimization scheme. The axial flow fan blade reference scheme comprises two parts: CFD calculation of lift and drag coefficients under multiple operating conditions, and weighted coefficient merging. The automated scheme comprises three parts: blade parameter modeling, automated numerical calculation, and automated flow field analysis, respectively achieving automated blade generation, automated flow field calculation, and automated flow field post-processing. The blade optimization scheme is a multi-objective optimization algorithm. The design method first selects an axial flow fan blade reference scheme, i.e., determines the lift and drag coefficients under multiple operating conditions using CFD methods, and merges the lift coefficients and drag coefficients under multiple operating conditions into a reference value using weighted coefficients. Secondly, the automated blade scheme achieves full-process automation of blade design under given input parameters. Finally, based on the blade profile optimization scheme, combined with the lift coefficient and drag coefficient reference values ​​of the blade profile reference scheme, and the blade profile automation scheme, a large-scale screening and optimization of axial flow fans was carried out through optimization algorithms, ultimately determining the aerodynamic blade profile of the high-performance straight-blade axial flow fan. Specifically, this includes the following steps:

[0007] The first step is to select a reference design for the axial flow fan blade profile, and obtain reference values ​​for the lift coefficient and drag coefficient. Specifically:

[0008] Step 1) Obtain the lift coefficient and drag coefficient of the original blade under multiple operating conditions through CFD calculation.

[0009] Step 2) Combine the lift coefficients under multiple operating conditions into a lift coefficient reference value by using weighting coefficients, and combine the drag coefficients under multiple operating conditions into a drag coefficient reference value by using weighting coefficients.

[0010] The second step is to automate the entire process of airfoil design under given input parameters using an airfoil automation solution. Specifically:

[0011] Step 3) Perform parametric modeling on the original blade profile, as follows:

[0012] Step 3.1) Describe the standard mid-curve curve in the original blade profile using a 5-point, 4th-order Bezier curve, such as... Figure 4 As shown, the details are as follows:

[0013] The five points are P1, P2, P3, P4, and P5. The coordinates of the starting point P1 and the ending point P5, used as reference points, are known. The three intermediate control points P2, P3, and P4 are to be determined. Through dimensionless processing, the points to be determined are converted into an inlet geometric angle X1, an outlet geometric angle X2, and four dimensionless parameters m1, m2, m3, and m4. These six parameters will be used to optimize the shape of the intermediate arc. The specific meanings and sources of parameters m1, m2, m3, m4, X1, and X2 are as follows: The inlet geometric angle X1 is the angle between the tangent of the standard arc curve at point P1 and the x-axis; the outlet geometric angle X2 is the angle between the tangent of the standard arc curve at point P5 and the x-axis. By finding the extension line PA of the tangents of the inlet and outlet geometric angles, the control point P2 is obtained between (P1, PA) through the linear difference of the dimensionless parameter m1; the control point P4 is obtained between (P5, PA) through the linear difference of the dimensionless parameter m2; the control point PB is obtained between (P2, P4) through the linear difference of the dimensionless parameter m3; and finally, the control point P3 is obtained between (PA, PB) through the linear difference of the dimensionless parameter m4.

[0014] Step 3.2) Describe the standard thickness distribution curve using two four-point, third-order Bezier curves, such as... Figure 5 As shown, the details are as follows:

[0015] In the two four-point, third-order Bezier curves, the control points describing the first Bezier curve are Q1, Q2, Q3, and Q4, and the control points describing the second Bezier curve are Q4, Q5, Q6, and Q7. These are defined by four dimensionless parameters t1, t2, t3, and t4, and the parameter y. c x c r cLE r cTE θ LE θ TE The standard thickness distribution curve is obtained, and its specific meaning and source are as follows:

[0016] t1, t2, t3, and t4 are four dimensionless parameters ranging from 0 to 1, and y c The maximum relative thickness, i.e., the y-axis coordinate corresponding to the maximum point of the standard thickness distribution curve of the original blade in the coordinate system, x c Let r be the x-axis coordinate corresponding to the maximum point of the standard thickness distribution curve of the original blade in the coordinate system. cLE r is the relative radius of the leading edge of the aerodynamic blade profile of a straight-blade axial fan. cTE θ is the relative radius of the trailing edge of the aerodynamic blade profile of the straight-blade axial flow fan. LE Let θ be the leading edge wedge angle. TE The trailing edge wedge angle is defined by control point Q1(0, r). cLE ), Q4(x c ,yc Q7(1, r) cTE Point QC is a fixed point, and control point Q4 is the connection point of the two Bezier curves. This connection point is used to determine the maximum relative thickness of the airfoil. The coordinates of point QC are (0, y). c The coordinates of point QD are (1, y). c The coordinates of point QE are (x...). c r cLE The extension of the leading edge wedge angle intersects the line connecting point QC and control point Q4 at point QA. The extension of the trailing edge wedge angle intersects the line connecting point QE and control point Q4 at point QB. Control point Q2 is obtained by linear difference between (Q1, QA) using the dimensionless parameter t1. Control point Q3 is obtained by linear difference between (Q4, QC) using the dimensionless parameter t3. Control point Q6 is obtained by linear difference between (Q7, QB) using the dimensionless parameter t2. Control point Q5 is obtained by linear difference between (Q4, QD) using the dimensionless parameter t4.

[0017] Step 3.3) The leading and trailing edge curves of the aerodynamic blade profile of the straight-blade axial flow fan are described by elliptic equations, as follows:

[0018] The parametric equation of the standard ellipse and its derivative equation are shown in (1) and (2).

[0019]

[0020] In the formula, a represents the length of the major semi-axis of the ellipse, b represents the length of the minor semi-axis of the ellipse, k represents the aspect ratio of the ellipse, x represents the x-coordinate of a point on the ellipse, and y represents the y-coordinate of a point on the ellipse. The angle parameter, x, ranges from 0 to 2π. ′ Indicates x with respect to the parameter The derivative of y ′ Indicates y with respect to the parameter The derivative of .

[0021] The leading edge curve, trailing edge curve, pressure side curve, and suction side curve are guaranteed to have first-order continuity at the connection point, meaning that the slopes of the leading edge curve, trailing edge curve, pressure side curve, and suction side curve are the same at the connection point. The subscript LE represents the leading edge, and the subscript TE represents the trailing edge; the aspect ratio k is given by the equation of the leading edge ellipse. LE The value of the leading edge wedge angle θ LE The parameters of the leading edge curve can be obtained. The range is determined by the given aspect ratio k of the trailing ellipse equation. TE The value, in relation to the trailing edge wedge angle θ TE The trailing edge curve parameters can be obtained. The range is given by the specific formula as described in (3). In the leading edge curve parameters By uniformly assigning parameters within a given range and then performing coordinate transformation, the leading edge curve can be obtained. The trailing edge curve parameters... By uniformly assigning parameters within a given range and then performing coordinate transformation, the trailing edge curve can be obtained.

[0022]

[0023] Step 3.4) Superimpose the standard thickness distribution of the original airfoil along the positive and negative directions of the normal direction of the standard arc in Step 3.1) to obtain the pressure side curve and the suction side curve. Then, splice the leading edge curve obtained in Step 3.3) to the front end of the pressure side and the suction side, and splice the trailing edge curve obtained in Step 3.3) to the rear end of the pressure side and the suction side to obtain the complete standardized airfoil.

[0024] Step 4) The standardized airfoil is transformed by coordinate transformation to obtain a parametric airfoil, which in turn yields a specific airfoil geometry file.

[0025] The third step involves, based on the blade profile optimization scheme, and combining the lift coefficient and drag coefficient reference values ​​from the blade profile reference scheme with the blade profile automation scheme, conducting large-scale screening and optimization of axial flow fans through optimization algorithms. The final aerodynamic blade profile for the high-performance straight-blade axial flow fan is determined as follows:

[0026] Step 5) Use a mesh drawing script program written in Python to call the Autogrid5 software to draw a mesh on the leaf-shaped geometry file from Step 4).

[0027] Step 6) Use the solver setup script program written in Python to call Fine software to set the boundary conditions of the blade fluid domain and perform numerical calculations.

[0028] Step 7) Call the CFview software to perform flow field post-processing using a post-processing script program written in Python to obtain numerical calculation results.

[0029] Step 8) Using the NSGA-II multi-objective optimization algorithm in Modefrontier software, the lift coefficient reference value and drag coefficient reference value of the automatic scheme are combined with the blade reference scheme to optimize and obtain the high-performance straight blade axial flow fan aerodynamic blade profile.

[0030] Compared with existing technologies, the present invention, employing the above technical solution, has the following beneficial effects:

[0031] (1) Compared with traditional modeling methods, the parametric modeling method adopted in this invention can reduce the number of control points by using the parametric method of superimposing thickness on the middle arc line, which can improve the efficiency of parametric modeling while accurately describing the blade shape.

[0032] (2) The automated numerical calculation and flow field analysis method adopted in this invention, compared with the traditional manual numerical calculation and flow field analysis, provides convenient Python interface and automatic structured grid generation module Autogrid5 and other tools, which can realize the full automation of the process from generating leaf shape data points, generating computational domain and grid, CFD calculation and data post-processing, which can greatly improve the calculation efficiency.

[0033] (3) The present invention adopts a multi-point optimization method. Compared with the traditional single-point optimization method, multi-point optimization can simultaneously optimize the working state of the blade profile under different angles of attack, so that the optimized blade profile can adapt to more working conditions, thereby determining the comprehensive aerodynamic performance of the fan blade profile under a wide range of variable working conditions, and thus screening high-performance straight blade axial flow fan aerodynamic blade profiles. Attached Figure Description

[0034] Figure 1 A flowchart illustrating the aerodynamic blade design method for high-performance straight-blade axial flow fans.

[0035] Figure 2 This is a flowchart of the parametric design method for airfoil shapes.

[0036] Figure 3 This is an aerodynamic blade profile diagram for a high-performance straight-blade axial flow fan.

[0037] Figure 4 This refers to the standardized arc curve in step 3.1).

[0038] Figure 5 This is the standardized thickness distribution curve in step 3.2).

[0039] Figure 6 To optimize the comparison image of the blade shape before and after. Detailed Implementation

[0040] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings:

[0041] This invention can be implemented in many different forms and should not be considered limited to the embodiments described herein. Rather, these embodiments are provided so that the invention will be thoroughly and completely disclosed and will fully express the scope of the invention to those skilled in the art. In the drawings, components are enlarged for clarity.

[0042] It should be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, and / or parts, these elements, components, and / or parts are not limited by these terms. These terms are merely used to distinguish elements, components, and / or parts from one another. Therefore, the first element, component, and / or part discussed below may be a second element, component, or part without departing from the teachings of this invention.

[0043] The present invention provides a method for designing aerodynamic blade profiles for a high-performance straight-blade axial flow fan, comprising the following steps:

[0044] Step 1) Obtain the lift coefficient and drag coefficient of the original blade under multiple operating conditions through CFD calculation.

[0045] Step 2) Combine the lift coefficient and drag coefficient into reference values ​​using weighting factors.

[0046] Step 3) Perform parametric modeling on the original blade profile. The specific steps are as follows:

[0047] Step 3.1) Describe the standard arc curve using a five-point, fourth-order Bezier curve, such as... Figure 4 As shown, the control points are P1, P2, P3, P4, and P5, with the starting point P1 and the ending point P5 fixed. The dimensionless parameters m1, m2, m3, and m4 are all 0.5, X1 = 5°, and X2 = 40°. The extensions of the exit and inlet geometric angles intersect at point PA. Control point P2 is obtained between (P1, PA) through the linear difference of the dimensionless parameter m1. Control point P4 is obtained between (P5, PA) through the linear difference of the dimensionless parameter m2. Control point PB is obtained between (P2, P4) through the linear difference of the dimensionless parameter m3. Finally, control point P3 is obtained between (PA, PB) through the linear difference of the dimensionless parameter m4.

[0048] Step 3.2) Describe the standard thickness distribution curve using two four-point, third-order Bezier curves, such as... Figure 5 As shown, given t1 = 0.31939, t2 = 0.70995, t3 = 0.51721, t4 = 0.5751, y c =0.07448m, x c =0.22m, r cLE =0.02m, r cTE =0.003m, θ LE = 35.857°, θ TE= 1.0293°. Control points Q1(0, 0.02), Q4(0.22, 0.07448), and Q7(1, 0.003) are fixed points. The coordinates of point QC are (0, 0.07448), the coordinates of point QD are (1, 0.07448), and the coordinates of point QE are (0.22, 0.02). The extension of the leading edge wedge angle intersects the line connecting point QC and control point Q4 at point QA. The extension of the trailing edge wedge angle intersects the line connecting point QC and control point Q4 at point QA. The line connecting QE and control point Q4 intersects at point QB. Control point Q2 is obtained by linear difference between (Q1, QA) using dimensionless parameter t1, control point Q3 is obtained by linear difference between (Q4, QC) using dimensionless parameter t3, control point Q6 is obtained by linear difference between (Q7, QB) using dimensionless parameter t2, and control point Q5 is obtained by linear difference between (Q4, QD) using dimensionless parameter t4.

[0049] Step 3.3) Both the leading edge curve and the trailing edge curve are described by the equation of an ellipse.

[0050] Given the equation of the leading edge ellipse and its aspect ratio k LE =1.0855, the aspect ratio k of the trailing ellipse equation TE =0.89165, leading edge wedge angle θ LE = 35.857°, tail edge wedge angle θ TE = 1.0293°. The aspect ratio k LE =1.0855 and leading edge wedge angle θ LE Substituting 35.857° into equation (3), we obtain the parameters of the leading edge ellipse equation. The range is 128.115° to 231.885°. The aspect ratio k... TE =0.89165 and leading edge wedge angle θ TE Substituting 1.0293° into equation (3), we obtain the parameters of the leading edge ellipse equation. The range is 90.918° to 269.082°.

[0051]

[0052]

[0053]

[0054] Step 3.4) Superimpose the standard thickness distribution of the original airfoil along the positive and negative directions of the normal direction of the arc in the standard of Step 3.1) to obtain the pressure side curve and the suction side curve. Then, splice the leading edge curve to the front end of the pressure side and the suction side, and splice the trailing edge curve to the rear end of the pressure side and the suction side to obtain the complete standardized airfoil.

[0055] Step 4) The standardized airfoil is transformed by coordinate transformation to obtain a parametric airfoil, which in turn yields a specific airfoil geometry file.

[0056] Step 5) Use a mesh drawing script program written in Python to call the Autogrid5 software to draw a mesh on the leaf-shaped geometry file from Step 4).

[0057] Step 6) Use the solver setup script program written in Python to call Fine software to set the boundary conditions of the blade fluid domain and perform numerical calculations.

[0058] Step 7) Call the CFview software to perform flow field post-processing using a post-processing script program written in Python to obtain numerical calculation results.

[0059] Step 8) Using the NSGA-II multi-objective optimization algorithm in Modefrontier software, combined with the results of the automated scheme and the lift coefficient and drag coefficient reference values ​​of the blade reference scheme, the high-performance straight-blade axial flow fan aerodynamic blade profile is optimized. The blade profiles before and after optimization are as follows: Figure 6 As shown.

[0060] The embodiments described above are merely illustrative of the implementation methods of the present invention, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A design method for the aerodynamic blade profile of a high-performance straight-blade axial flow fan, characterized in that, The design method includes an axial fan blade reference scheme, an automated blade scheme, and an optimized blade scheme. The axial fan blade reference scheme includes two parts: CFD calculation of lift coefficient and drag coefficient under multiple operating conditions, and weighted coefficient merging. The automated scheme includes three parts: blade parameter modeling, automated numerical calculation, and automated flow field analysis, which respectively realize automated blade generation, automated blade flow field calculation, and automated blade flow field post-processing. The leaf shape optimization scheme is a multi-objective optimization algorithm scheme; The design method first selects a reference scheme for the axial flow fan blade profile, and then obtains reference values ​​for the lift coefficient and drag coefficient under multiple operating conditions. Secondly, the blade profile automation scheme achieves full-process automation of blade profile under given input parameters; finally, based on the blade profile optimization scheme, combined with the lift coefficient reference value and drag coefficient reference value of the blade profile reference scheme, and the blade profile automation scheme, the axial flow fan is screened and optimized on a large scale through the optimization algorithm, and finally the aerodynamic blade profile of the high-performance straight blade axial flow fan is determined. Specifically, the following steps are included: The first step is to select a reference design for the axial flow fan blade profile and obtain reference values ​​for the lift coefficient and drag coefficient. Specifically: Step 1) Calculate the lift coefficient and drag coefficient of the original blade profile under multiple operating conditions using CFD. Step 2) Combine the lift coefficients under multiple operating conditions into a lift coefficient reference value by using weighting coefficients, and combine the drag coefficients under multiple operating conditions into a drag coefficient reference value by using weighting coefficients. The second step is to automate the entire process of airfoil design under given input parameters using an airfoil automation solution. Specifically: Step 3) Perform parametric modeling on the original blade profile, as follows: Step 3.1) Describe the standard arc curve in the original blade profile using a 5-point, 4th-order Bezier curve; Step 3.2) Describe the standard thickness distribution curve using two four-point third-order Bezier curves; Step 3.3) The leading edge curve and trailing edge curve of the aerodynamic blade profile of the straight blade axial flow fan are described by the elliptic equation, and the leading edge curve and trailing edge curve are obtained respectively; Step 3.4) Superimpose the standard thickness distribution of the original blade profile along the positive and negative directions of the normal direction of the standard arc in Step 3.1) to obtain the pressure side curve and the suction side curve; then, splice the leading edge curve obtained in Step 3.3) to the front end of the pressure side and the suction side, and splice the trailing edge curve obtained in Step 3.3) to the rear end of the pressure side and the suction side to obtain the complete standardized blade profile; Step 4) The standardized airfoil is transformed by coordinate transformation to obtain a parametric airfoil, which in turn yields a specific airfoil geometry file; The third step involves, based on the blade profile optimization scheme, and combining the lift coefficient and drag coefficient reference values ​​from the blade profile reference scheme with the blade profile automation scheme, conducting large-scale screening and optimization of axial flow fans through optimization algorithms. The final aerodynamic blade profile for the high-performance straight-blade axial flow fan is determined as follows: Step 5) Use a mesh drawing script program written in Python to call the Autogrid5 software to draw a mesh on the leaf geometry file from Step 4; Step 6) Use the solver setup script program written in Python to call Fine software to set the boundary conditions of the blade fluid domain and perform numerical calculations; Step 7) Use a post-processing script program written in Python to call CFview software to perform flow field post-processing and obtain numerical calculation results; Step 8) Using the NSGA-II multi-objective optimization algorithm in Modefrontier software, the lift coefficient reference value and drag coefficient reference value of the automatic scheme are combined with the blade reference scheme to optimize and obtain the high-performance straight blade axial flow fan aerodynamic blade profile.

2. The design method for the aerodynamic blade profile of a high-performance straight-blade axial flow fan according to claim 1, characterized in that, Step 3.1) is as follows: The five points are P1, P2, P3, P4, and P5, with the starting point P1 and the ending point P5 serving as reference coordinates. The three intermediate control points P2, P3, and P4 are to be determined. Through dimensionless processing, the points to be determined are converted into an inlet geometric angle X1, an outlet geometric angle X2, and four dimensionless parameters m1, m2, m3, and m4. These six parameters will be used to optimize the shape of the intermediate arc. The specific meanings and sources of parameters m1, m2, m3, m4, X1, and X2 are as follows: The inlet geometric angle X1 is the tangent line to the standard intermediate arc curve at point P1 and the x-axis. The exit geometric angle X2 is the angle between the tangent line to the standard arc curve at point P5 and the X-axis. By finding the extensions PA of the tangent lines of the inlet and outlet geometric angles, control point P2 is obtained between (P1, PA) through linear difference with dimensionless parameter m1. Control point P4 is obtained between (P5, PA) through linear difference with parameter m2. Control point PB is obtained between (P2, P4) through linear difference with dimensionless parameter m3. Finally, control point P3 is obtained between (PA, PB) through linear difference with dimensionless parameter m4.

3. The design method for the aerodynamic blade profile of a high-performance straight-blade axial flow fan according to claim 1, characterized in that, Step 3.2) is as follows: In the two four-point, third-order Bezier curves, the control points describing the first Bezier curve are Q1, Q2, Q3, and Q4, and the control points describing the second Bezier curve are Q4, Q5, Q6, and Q7; using four dimensionless parameters t1, t2, t3, t4, and parameter y... c x c r cLE r cTE θ LE θ LE The standard thickness distribution curve is obtained, and its specific meaning and source are as follows: t1, t2, t3, and t4 are four dimensionless parameters ranging from 0 to 1, and y c The maximum relative thickness, i.e., the y-axis coordinate corresponding to the maximum point of the standard thickness distribution curve of the original blade in the coordinate system, x c Let r be the x-axis coordinate corresponding to the maximum point of the standard thickness distribution curve of the original blade in the coordinate system. cLE r is the relative radius of the leading edge of the aerodynamic blade profile of a straight-blade axial fan. cTE θ is the relative radius of the trailing edge of the aerodynamic blade profile of the straight-blade axial flow fan. LE Let θ be the leading edge wedge angle. TE The trailing edge wedge angle; control point Q1(0, r cLE ), Q4(x c ,y c Q7(1, r) cTE Point QC is a fixed point, and control point Q4 is the connection point of the two Bezier curves. The connection point is used to determine the maximum relative thickness of the airfoil; the coordinates of point QC are (0, y). c The coordinates of point QD are (1, y). c The coordinates of point QE are (x...). c r cLE The extension of the leading edge wedge angle intersects the line connecting point QC and control point Q4 at point QA. The extension of the trailing edge wedge angle intersects the line connecting point QE and control point Q4 at point QB. Control point Q2 is obtained by linear difference between (Q1, QA) using the dimensionless parameter t1. Control point Q3 is obtained by linear difference between (Q4, QC) using the dimensionless parameter t3. Control point Q6 is obtained by linear difference between (Q7, QB) using the dimensionless parameter t2. Control point Q5 is obtained by linear difference between (Q4, QD) using the dimensionless parameter t4.

4. The design method for the aerodynamic blade profile of a high-performance straight-blade axial flow fan according to claim 1, characterized in that, Step 3.3) is as follows: The parametric equations of the standard ellipse and their derivative equations are shown in (1) and (2); In the formula, a represents the length of the major semi-axis of the ellipse, b represents the length of the minor semi-axis of the ellipse, k represents the aspect ratio of the ellipse, x represents the x-coordinate of a point on the ellipse, and y represents the y-coordinate of a point on the ellipse. The angle parameter, x, ranges from 0 to 2π. ′ Indicates x with respect to the parameter The derivative of y, y′ represents y with respect to the parameter The derivative; The leading edge curve, trailing edge curve, pressure side curve, and suction side curve are guaranteed to have first-order continuity at the connection point, meaning that the slopes of the leading edge curve, trailing edge curve, pressure side curve, and suction side curve are the same at the connection point; the subscript LE is defined to represent the leading edge, and the subscript TE to represent the trailing edge; the aspect ratio k is given by the equation of the leading edge ellipse. LE The value of the leading edge wedge angle θ LE The parameters of the leading edge curve are obtained. The range is determined by the given aspect ratio k of the trailing ellipse equation. TE The value, in relation to the trailing edge wedge angle θ TE The trailing edge curve parameters are obtained. The range is specified in the formula (3); in the leading edge curve parameters Parameters are uniformly given within a range, and then the leading edge curve is obtained through coordinate transformation. The trailing edge curve parameters are then... The parameters are uniformly given within a range, and then the trailing edge curve is obtained through coordinate transformation;

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