A 3D model modeling method of a cooling fan based on STARCCM+ software

Abstract

The present invention discloses a three-dimensional model modeling method for a cooling fan based on STARCCM+ software and an electronic device. The method includes the following steps: S1, preset the basic shape parameters of the fan; S2, obtain the blade characteristic parameters of different cross-sections; S3, calculate the planar coordinates of the discrete points of the blade cross-section line according to the parametric expression of the mean camber line and the blade thickness variation law; S4, convert the planar coordinates of the discrete points of the blade cross-section line into a corresponding set of spatial coordinate points; S5, translate the different cross-sections according to the stacking deformation law, generate multiple leading lines and obtain the set of spatial coordinate points of the multiple leading lines; S6, generate an initial fan model and record a macro file; S7, run the macro file in STARCCM+ to obtain the three-dimensional model of the initial fan. By performing model parameterization processing and writing a macro file, the problem of parameterization processing of three-dimensional surfaces in the software is solved, and the modeling process of CAD software is omitted.

Description

Technical Field

[0001] The present invention belongs to the field of data processing methods applicable to specific applications, and particularly relates to a method for modeling a three-dimensional model of a cooling fan based on STARCCM+ software. Technical Background

[0002] STARCCM+ software is a commonly used software tool in computational fluid analysis and can be used to simulate and analyze the aerodynamic performance of cooling fans. Usually, a 3D model of the fan is created using CAD software and then imported into STARCCM+ software for mesh generation and computational solution. Since the curved surface shape of the fan blades is complex and the cross-section from the blade tip to the blade root needs to continuously adjust the dimensional parameters according to the performance objectives, the modeling process is cumbersome and inefficient, thus prolonging the development cycle and increasing the development cost.

[0003] The existing STARCCM+ software has few modeling functions and can only generate specific three-dimensional models using known feature points, without complex curved surface modeling functions. How to achieve parametric processing of three-dimensional curved surfaces in STARCCM+ software is a difficult problem in this field. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem of how to achieve parametric processing of three-dimensional curved surfaces in STARCCM+ software in the prior art, thereby greatly reducing the modeling time.

[0005] To solve the above problems, the present invention provides a method for modeling a three-dimensional model of a cooling fan based on STARCCM+ software. The geometric dimensions of the fan are parametrically processed according to the fan shape characteristics, the blade cross-section lines and guide lines are generated according to relevant parameters, imported into STARCCM+ software to generate the three-dimensional models of the blades and the entire fan, and then the automation of the modeling process is realized by recording the JAVA macro file of STARCCM+ software. Finally, the automatic generation of the three-dimensional model of the fan in the software according to the input parameters is realized.

[0006] The present invention provides a method for modeling a three-dimensional model of a cooling fan based on STARCCM+ software. The method is implemented based on STARCCM+ software and includes the following steps:

[0007] S1. Preset the basic shape parameters of the fan;

[0008] S2. Obtain the blade feature parameters of different cross-sections according to design experience or by referring to the original fan model. The blade cross-sections include the blade tip cross-section, the blade root cross-section, and the intermediate cross-section between the two.

[0009] S3. Calculate the parametric expression of the mean camber line for each blade section based on the blade characteristic parameters, and calculate the planar coordinates of the discrete points on the blade section line according to the parametric expression of the mean camber line and the blade thickness variation law;

[0010] S4. Convert the planar coordinates of the discrete points on the blade section line into a corresponding set of spatial coordinate points according to the radial height of the different sections;

[0011] S5. Translate the different sections according to the stacking deformation law to generate multiple guide lines and obtain the set of spatial coordinate points of the multiple guide lines;

[0012] S6. In the STARCCM+ three-dimensional design function, import the set of spatial coordinate points of the blade root section, blade tip section and multiple guide lines to generate an initial fan model and record a macro file;

[0013] S7. Run the macro file in STARCCM+ to obtain the three-dimensional model of the parameterized initial fan.

[0014] Further, the fan in step S1 includes an open fan and an annular fan. For the open fan, the basic shape parameters include the fan radius R t , the hub radius R b , the number of blades Q, and the hub height H1; for the annular fan, the basic shape parameters further include the blade ring width W and the blade ring height H2.

[0015] Further, step S2 includes the following specific contents:

[0016] S21. Set N blade sections, then the radial height difference Δr between adjacent sections = (R t - R b ) / (N - 1), where R t is the fan radius and R b is the hub radius;

[0017] S22. Draw a cylindrical section in the original fan model according to the calculated radial height difference of the sections to obtain the blade section line and the mean camber line at the corresponding height; taking the leading edge endpoint of the mean camber line of each section as the origin, establish a local plane coordinate system with the fan axis and the circumferential tangent direction where the leading edge endpoint is located, expand each cylindrical section line and the mean camber line to the XY plane of the local plane coordinate system, and then measure the mean camber line on each XY plane in turn to obtain the blade characteristic parameters of the corresponding section. The blade characteristic parameters include the leading edge flow angle θ1, the trailing edge flow angle θ2, the chord length L, the installation angle λ and the section thickness t.

[0018] Further, step S3 includes the following specific contents:

[0019] S31. Describe the mean camber line with a cubic polynomial function. According to the local plane coordinate system, establish the fitting function expression of the mean camber line:

[0020] y = a0 + a1x + a2x 2 + a3x 3 (1)

[0021] Substitute the coordinates of the known starting point and ending point (0, 0), (L, 0) of the mean camber line, as well as the starting point derivative y1′ = tan(θ1), the ending point derivative y2′ = -tan(θ2), where θ1 is the leading-edge flow angle, θ2 is the trailing-edge flow angle, and L is the chord length, into the fitting function expression (1) to find the undetermined coefficients a0, a1, a2, a3. Rotate the mean camber line around the leading-edge endpoint by the installation angle λ to obtain the actual mean camber line;

[0022] S32. Divide each blade section line into a pressure surface, a suction surface, a leading-edge end surface, and a trailing-edge end surface. Define a plurality of equally spaced discrete points on each of these surfaces;

[0023] S33. Calculate the XY plane coordinates of the discrete points in the local plane coordinate system according to the mean camber line fitting function expression and the thickness distribution law.

[0024] Furthermore, the specific content of step S4 includes the following:

[0025] Convert the coordinate points of the discrete points obtained in step S3 on the local plane coordinate XY to the cylindrical surface at the corresponding section height in the three-dimensional XYZ coordinate system. In the three-dimensional XYZ coordinate system, the directions of the X and Y axes are the same as those in the plane coordinate system. Determine the Z axis according to the left-hand rule. After conversion, the x coordinate of the point on the cylindrical surface is the same as the plane coordinate x before conversion. Then, the transformation formula is derived as follows:

[0026] x′ = x

[0027] y′ = R n sinθ

[0028] Z′ = R n cosθ

[0029] where R n is the radial height where the section is located, θ = arctan(y / Rn), and θ is the angle between the coordinate point and the Z axis.

[0030] Furthermore, the specific content of step S5 includes the following:

[0031] S51. By applying different XY translation amounts to each section, different stacking forms of the blade can be achieved, including bending shapes and degrees in different directions;

[0032] S52. In the set of discrete point spatial coordinates of each cross-section generated in step S4, on the suction surface, pressure surface, leading edge end surface, and trailing edge end surface, select multiple discrete points with the same number respectively as the guide line feature points and mark them with the serial numbers of the discrete points on the corresponding surfaces. Then, extract the marked points with the same serial number of each cross-section in the same direction in sequence to form a guide line coordinate set, and generate multiple guide line coordinate sets.

[0033] Further, the application of different XY translation amounts to each cross-section includes the following specific content: For the multiple cross-sections intercepted in step S22, establish a local plane coordinate system with one of the cross-sections as the reference cross-section, expand and project the remaining cross-sections onto the XY plane of the local plane coordinate system. By measuring the xy coordinate differences of the leading edge airflow angle endpoints between other cross-sections and the reference cross-section, the offset amounts of all cross-sections relative to the reference cross-section can be obtained.

[0034] Further, step S6 includes the following specific content:

[0035] S61. Enter the STARCCM + 3D - CAD design function, turn on the macro recording function to start recording the operation process, create multiple 3D sketches. The number of 3D sketches is equal to the sum of the root cross-section, tip cross-section, and the number of guide lines. Import the root cross-section, tip cross-section, and all guide lines into the 3D sketches respectively to generate a blade model, and then generate Q blade models through the array function;

[0036] S62. Draw a hub in the XZ plane, generate a hub model with a height of H1 through the rotation function. For the annular fan, a shroud model also needs to be generated according to the shroud width W and shroud height H2. After completion, perform a Boolean operation on all models to obtain the original three-dimensional fan model and save the macro file.

[0037] Further, the solid modeling method further includes:

[0038] Define the characteristic parameters in the macro file in step S6 as functions and point to the prepared spreadsheet;

[0039] Fill the modified fan design parameter data into the corresponding positions in the spreadsheet to obtain the modified macro file;

[0040] Run the modified macro file in STARCCM + to obtain the three-dimensional model of the fan with modified parameters.

[0041] The present invention also provides an electronic device, including: one or more processors; a memory for storing one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors implement the three-dimensional model modeling method of a cooling fan based on STARCCM+ software.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. The present invention uses STARCCM+ software to complete the 3D modeling of the fan, and then directly conducts simulation analysis in STARCCM+ software, eliminating the modeling process of CAD software, reducing the dependence on CAD software for simulation analysis; simplifying the operation process, and only using the simulation analysis software to complete the whole process of fan modeling to simulation, saving time costs;

[0044] 2. The present invention is applied to the rapid modeling of the input model for CFD simulation analysis, focusing on analyzing the influence of different parameter combinations on performance. The entire modeling process only uses the basic point-line-plane modeling function and a small number of parameters of STARCCM+ software, and completes the creation of the fan blade model through fewer section lines and guide lines. The obtained parametric model meets the accuracy requirements of engineering analysis;

[0045] 3. On the basis of realizing the parametric modeling of the open fan, the present invention adds a parametric structure of the shroud, realizes the parametric modeling of the annular fan, and expands the application range of the fan parametric model. Description of the Drawings

[0046] Figure 1 Schematic diagram of the basic shape parameters of the fan;

[0047] Figure 2 Schematic diagram of the characteristic parameters of the mid-arc line of the blade section;

[0048] Figure 3 Schematic diagram of the transformation from plane coordinates to cylindrical space coordinates;

[0049] Figure 4 Schematic diagram of the discrete point set of the blade section line;

[0050] Figure 5 Schematic diagram of the offset of the blade section line and the generation of 9 section lines;

[0051] Figure 6 Schematic diagram of importing section lines and guide lines in STARCCM+ software for blade modeling;

[0052] Figure 7 Schematic diagram of the fan hub and shroud section modeling in STARCCM+ software;

[0053] Figure 8 It is a schematic diagram of a 9 - blade fan modeled in STARCCM+ software and an 8 - blade fan model generated after modifying parameters. Specific implementation manners

[0054] The following further elaborates on the present invention in detail in conjunction with the attached drawings and specific embodiments:

[0055] The purpose of this invention patent is to provide a method for solid modeling of a fan based on STARCCM+ software to solve the problem of low fan modeling efficiency in the prior art.

[0056] The method for solid modeling of a fan based on STARCCM+ software described in this invention patent includes the following steps:

[0057] S1. Preset the basic shape parameters of the fan;

[0058] S2. Obtain the blade characteristic parameters of different cross - sections according to design experience or by referring to the original fan model. The blade cross - sections include the tip cross - section, the root cross - section, and the intermediate cross - section located between the two;

[0059] S3. Calculate the parametric expressions of the middle arcs in each blade cross - section according to the blade characteristic parameters, and calculate the planar coordinates of the discrete points of the blade cross - section lines according to the parametric expressions of the middle arcs and the blade thickness variation law;

[0060] S4. Convert the planar coordinates of the discrete points of the blade cross - section lines into corresponding spatial coordinate point sets according to the radial heights of the different cross - sections;

[0061] S5. Translate the different cross - sections according to the stacking deformation law to generate multiple guide lines and obtain the spatial coordinate point sets of the multiple guide lines;

[0062] S6. In the STARCCM+ three - dimensional design function, import the spatial coordinate point sets of the root cross - section, the tip cross - section, and the multiple guide lines to generate an initial fan model and record a macro file;

[0063] S7. Run the macro file in STARCCM+ to obtain the three - dimensional model of the initial fan after parameterization;

[0064] S8. Define the characteristic parameters in the macro file in step S6 as functions and point to the prepared spreadsheet;

[0065] S9. Fill the modified fan design parameter data into the corresponding positions in the spreadsheet in step S8 and obtain the modified macro file;

[0066] S10. Run the modified macro file in STARCCM+ to obtain the three - dimensional model of the fan after modifying the parameters.

[0067] Steps S8 - S10 in this embodiment are to illustrate that a new model can be regenerated by simply modifying relevant parameters in this embodiment.

[0068] The present invention uses STARCCM+ software to complete the 3D modeling of the fan, and then directly conducts simulation analysis in STARCCM+ software, eliminating the modeling process of CAD software, reducing the dependence on CAD software for simulation analysis; simplifying the operation process, and only using simulation analysis software can complete the whole process of the fan from modeling to simulation, saving time costs; moreover, on the basis of realizing the parametric modeling of the open fan, the present invention adds a parametric structure of the shroud ring, realizes the parametric modeling of the annular fan, and expands the application range of the parametric model of the fan.

[0069] In practical applications, it can be divided into two categories: annular fans and open fans according to the presence or absence of a shroud ring. This embodiment is an annular fan. As Figure 1 shown, the preset basic shape parameters of the fan in step S1 include the fan radius R t , the hub radius R b , the number of blades Q, and the hub height H1; for the annular fan, the basic shape parameters also include the shroud ring width W and the shroud ring height H2.

[0070] In this embodiment, in step 2, 9 blade cross-sections are set, and the radial height difference Δr of the cross-sections = (R t - R b ) / (9 - 1). Cross-section 1 is the root cross-section of the blade, and the radial height R1 = R b . The radial height R2 of cross-section 2 = R b + Δr, and so on. Cross-section 9 is the tip cross-section of the blade, and the radial height R9 = R t . If referring to the original fan for modeling, then draw cylindrical cross-sections in the original fan model according to the calculated heights of each cross-section to obtain the blade cross-section lines and mid-arcs at the corresponding heights. Taking the leading-edge endpoint of the mid-arc of the cross-section as the origin, establish a local plane coordinate system. Define the axial direction of the fan as the X direction, and the circumferential tangent direction where the leading-edge endpoint is located as the Y direction. Expand each cylindrical cross-section line and mid-arc to the XY plane of the local plane coordinate system, and then measure the mid-arcs on each XY plane in turn to obtain the blade characteristic parameters of the corresponding cross-section: the leading-edge airflow angle θ1, the trailing-edge airflow angle θ2, the chord length L, the installation angle λ, and the cross-section thickness t. If there is no original fan, the above blade characteristic parameters of each cross-section can be directly defined according to design experience.

[0071] In this embodiment, in step 3, the parametric modeling steps of the fan blade cross-section are as follows:

[0072] S31. As Figure 2As shown, in the local plane coordinate system established in step 2, to ensure the smoothness of the curve and the uniqueness of the mean camber line under three parameters, the mean camber line is described by a cubic polynomial function: According to the local plane coordinate system, a fitting function table of the mean camber line is established.

[0073] Expression: y = a0 + a1x + a2x 2 + a3x 3 (1)

[0074] Substitute the coordinates of the starting point and the ending point (0, 0), (L, 0) of the mean camber line, as well as the starting point derivative y1′ = tan(θ1) and the ending point derivative y2′ = -tan(θ2) into the fitting function expression (1) to find the undetermined coefficients a0, a1, a2, a3. Rotate the mean camber line around the leading edge endpoint by the installation angle λ to obtain the actual mean camber line, where θ1, θ2, and L are the blade characteristic parameters measured in step 2.

[0075] S32. As Figures 4 - 5 shown, divide each blade section line into four segments: the pressure surface, the suction surface, the leading edge end surface, and the trailing edge end surface. Define a certain number of equally spaced discrete points on each part of the section line, with 19 points on each of the two end surfaces, 101 points on the suction surface and the pressure surface respectively, for a total of 240 points. Among them, 9 cross-section discrete point sets are calculated according to the mean camber line formula and the thickness t. The leading edge angle end surface endpoint is the starting point, the discrete point numbers on the leading edge end surface are 1 - 19, the discrete point numbers on the suction surface are 20 - 120, the discrete point numbers on the trailing edge flow angle end surface are 121 - 139, and the discrete point numbers on the pressure surface are 140 - 240.

[0076] S33. Calculate the XY plane coordinates of 240 discrete points in the local plane coordinate system according to the mean camber line fitting formula and the thickness distribution law.

[0077] In this embodiment, as Figure 3 shown, in step 4, convert the coordinate points on the XY plane of the plane coordinate system in step S33 to the cylindrical surface at the corresponding cross-section height in the three-dimensional XYZ coordinate system. Among them, the X and Y axis directions in the three-dimensional XYZ coordinate system are the same as those in the plane coordinate system, and the Z axis is determined according to the left-hand rule. After conversion, the x coordinate of the point on the cylindrical surface is the same as the plane coordinate x before conversion, and the following transformation formula is derived:

[0078] x′ = x

[0079] y′ = R n sinθ

[0080] z′ = R n cosθ

[0081] where R nis the radial height where the cross-section is located, θ = arctan(y / Rn), and θ is the angle between the coordinate point and the Z-axis.

[0082] In this embodiment, the step S5 includes the following specific contents:

[0083] S51. By applying different XY translation amounts to each cross-section, different stacking forms of the blade can be achieved, including bending shapes and degrees in different directions;

[0084] In this embodiment, the method based on the original fan model is as follows: for the multiple cross-sections intercepted in step S22, a local plane coordinate system is established with one of the cross-sections as the reference cross-section, and the remaining cross-sections are unfolded and projected onto the XY plane of the local plane coordinate system. By measuring the xy coordinate differences between the leading-edge airflow angle endpoints of other cross-sections and the reference cross-section, the offset amounts of all cross-sections relative to the reference cross-section can be obtained. For the case without a basic model, the xy offset amounts are arranged according to certain rules based on design experience.

[0085] S52. As Figure 6 shown, in the set of discrete point spatial coordinates of each cross-section generated in step S4, 3 specific serial number points are taken respectively on the suction surface, pressure surface, and two end surfaces. The same serial number points of each cross-section are extracted in sequence in the same direction to form a set of guide line coordinates, and a total of 12 sets of guide line coordinates are generated. The cross-section point set is saved and renamed as sectionline1~9.csv, and the guide line point set is saved and renamed as guideline1~12.csv.

[0086] In this embodiment, as Figure 7 shown, in step 6, enter the STARCCM+ 3D-CAD design function, turn on the macro recording function to start recording the operation process, create multiple 3D sketches, and the number of sketches is equal to the sum of the number of root cross-sections, tip cross-sections, and guide lines. Import the root cross-section, tip cross-section, and 12 guide lines into the 3D sketches, select all the cross-section lines and guide lines using the loft command to generate the blade model, and then generate Q blade models through the array function. Draw the hub on the XZ plane and generate the hub model with a height of H1 through the rotation function. For the annular fan, a blade ring model also needs to be generated according to the blade ring width W and blade ring height H2. After completion, perform a Boolean operation on all the models to obtain the original fan three-dimensional model and save the macro file.

[0087] In this embodiment, in step 7, a parameter table containing shape parameters is compiled. In the recorded macro file, the input shape parameters are changed to functions, and code for file reading is added to read the compiled parameter table into the function.

[0088] By parameterizing the model and writing a macro file, it is possible to automatically create a fan model with corresponding parameters in the STARCCM+ software. Thus, a new fan model can be directly and quickly generated by modifying the parameters, and the cumbersome steps of modeling in CAD software and then importing are eliminated, facilitating the subsequent analysis and the process of improving and optimizing the model, thereby improving the development efficiency of the fan.

[0089] This method is applied to the rapid modeling of the input model for CFD simulation analysis. It does not require ensuring a very high surface quality. The entire modeling process only uses the basic point, line, and surface modeling functions of the STARCCM+ software, without using the functions of creating and parameter editing of complex curves such as nurbs curves in commercial CAD modeling software like CATIA, significantly reducing the learning cost of simulation analysis software and the usage cost of commercial software for technicians.

[0090] Taking the modeling process of a 9 - blade annular engine cooling fan as an example, this method is described in detail.

[0091] The basic shape parameters are: fan radius R t = 309.2 mm, hub radius such as R b = 123.7 mm, hub axial height H1 = 60 mm, number of blades Q = 9, blade ring width W = 56 mm, blade ring height H2 = 5 mm.

[0092] The radial height difference Δr of the cross - section = (R t - R b ) / (9 - 1)= 23 mm. Nine cross - sections at corresponding positions are intercepted on the blade, and the characteristic parameters measured are shown in Table 1 below:

[0093]

[0094]

[0095] Table 1

[0096] A cubic polynomial is used to fit the middle arc of the blade. Taking one end of the middle arc as the origin, nine cross - section middle arcs are calculated according to the method described in step 3 based on the above parameters.

[0097] According to the middle - arc formula and the thickness T, a discrete point set of nine cross - sections is calculated. The starting point is the end - point of the leading - edge angle end - face. The discrete point numbers of the leading - edge end - face are 1 - 19, the discrete point numbers of the suction surface are 20 - 120, the discrete point numbers of the trailing - edge airflow - angle end - face are 121 - 139, and the discrete point numbers of the pressure surface are 140 - 240.

[0098] A cylindrical coordinate system is established. The discrete point set of the cross - section calculates the spatial coordinates of the cross - section line point set according to the radial height Rn of the cross - section where it is located.

[0099] At this time, the leading-edge end faces of each cross-sectional line coincide, forming a straight-blade form for the blade. Since this fan blade is a circumferentially curved blade, according to the XY offset (Δx, Δy) of different cross-sections relative to the root cross-section, the coordinate points of the corresponding cross-sections are translated to obtain the spatial coordinates of the final cross-sectional line. The translated cross-sectional coordinate points are shown in Table 2 below (only the coordinate points numbered 1 - 50 in 3 cross-sections are listed for illustration):

[0100]

[0101]

[0102] Table 2

[0103] As Figure 6 shown, 3 fixed points are taken from each of the 4 segments of the cross-sectional line as the guide-line point set, a total of 12 points corresponding to the numbers 1, 10, 19, 45, 70, 95, 121, 130, 139, 165, 190, 215

[0104] Save the cross-sectional point set and rename it as sectionline 1 - 9.csv. Take the points with the same number in the above-mentioned cross-sections in sequence as the guide-line point set, a total of 12 guide-line point sets are generated, and they are renamed as guideline 1 - 12.csv according to the order of the point numbers.

[0105] Enter the STARCCM + 3D - CAD design function, turn on the macro recording function to start recording the operation process. Create 14 3D sketches, import cross-section 1, cross-section 9 and 12 guide-lines into the 3D sketches in sequence, use the loft command to select all the cross-sectional lines and guide-lines, generate the 3D model of the blade, and then generate 9 blade models through the array function.

[0106] Draw a rectangle with a length of 60 mm in the X direction and a length of 123.7 mm in the Y direction on the XY plane as the hub cross-section, and generate the 3D model of the hub through the revolve and extrude function.

[0107] Draw an L-shaped profile with a length of 56 mm in the X direction and a length of 5 mm in the Y direction on the XY plane as the shroud cross-section, and generate the 3D model of the shroud through the revolve and extrude function.

[0108] Based on realizing the parametric modeling of the open fan, the present invention adds a parametric structure of the shroud, realizes the parametric modeling of the annular fan, and expands the application range of the parametric model of the fan.

[0109] After completion, perform Boolean operations on all the models to obtain the 3D model of the fan.

[0110] Compile to include the shape parameter fan radius R t 、hub radius R b, a parameter table of the number of blades Q, hub height H1, blade ring width W, and blade ring height H2. In the recorded macro file, change the corresponding shape parameters to function representations, add code for file reading at the head of the file, and point the function to the corresponding positions in the parameter table.

[0111] As Figure 8 shown, at this time, based on the generated 9-blade fan, change the number of blades to 8, increase the chord length of the blade root section to 110 mm, and increase the chord length of the blade tip section to 160 mm. Then, by modifying the number of blades in the parameter table, the new section and guide line point sets can be calculated according to the changed chord lengths, as shown in Table 3 below (only the coordinate points numbered 1 - 50 in 3 sections are listed for illustration).

[0112]

[0113]

[0114]

[0115] Table 3

[0116] Open the STARCCM+ software and run the macro command. First, fill in the parameters in Table 1. The script recalculates the section line and guide line according to the new relevant parameters in the input Table 1, generates the section line and guide line point sets, and automatically imports them into the STARCCM+ software to generate a 3D model of the 8-blade fan with modified parameters.

[0117] The following two optimization schemes are obtained by changing the values of the relevant parameters in Table 2 of the above embodiment. For example, the leading edge angle in Optimization Scheme 1 is changed to 1.15 times that in the above embodiment, and other values are changed correspondingly according to Table 4 below.

[0118]

[0119] Table 4

[0120] Perform simulation test verification on the parameterized model and the engineering model bench obtained in the above scheme at the same time. After normalizing the results, the data in Table 5 below are obtained. The relative deviation between the simulation and test results is less than 5%, meeting the engineering requirements.

[0121]

[0122] Table 5

[0123] The present invention also provides an electronic device, including: one or more processors; a memory for storing one or more programs; when the one or more programs are executed by the one or more processors, enabling the one or more processors to implement the three-dimensional model modeling method of a cooling fan based on STARCCM+ software.

[0124] The above-described invention only expresses the implementation manners of the embodiments of the present invention, and thus cannot be construed as a limitation on the scope of the invention patent, nor is it a limitation on the structure of the embodiments of the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the embodiments of the present invention, several changes and improvements can still be made, and these all belong to the protection scope of the embodiments of the present invention.

Claims

1. A three-dimensional model modeling method of a cooling fan based on STARCCM+ software, characterized in that The method is implemented based on the STARCCM+ software and includes the following steps: S1. Preset the basic shape parameters of the fan; S2. Obtain the blade characteristic parameters of different cross-sections according to design experience with reference to the original fan model. The blade cross-sections include the tip cross-section, the root cross-section, and the intermediate cross-section located between the two; S3. Calculate the parametric expression of the mean camber line of each blade cross-section according to the blade characteristic parameters, and calculate the planar coordinates of the discrete points of the blade cross-section line according to the parametric expression of the mean camber line and the blade thickness variation law; The specific content of step S3 is as follows: S31. Describe the mean camber line with a cubic polynomial function: Establish the fitting function expression of the mean camber line according to the local planar coordinate system, y = a0 + a1x + a2x 2 + a3x 3 (1) Substitute the coordinates of the known starting point (0, 0) and ending point (L, 0) of the mean camber line, as well as the starting derivative y1' = tan(θ1) and the ending derivative y2' = -tan(θ2), where θ1 is the leading-edge airflow angle, θ2 is the trailing-edge airflow angle, and L is the chord length, into the fitting function expression (1) to find the undetermined coefficients a0, a1, a2, a3, and rotate the mean camber line around the leading-edge endpoint by the installation angle λ to obtain the actual mean camber line; S32. Divide each blade cross-section line into a pressure surface, a suction surface, a leading-edge end surface, and a trailing-edge end surface, and define a plurality of equally spaced discrete points on each of these surfaces; S33. Calculate the XY planar coordinates of the discrete points in the local planar coordinate system according to the mean camber line fitting function expression and the thickness distribution law; S4. Convert the planar coordinates of the discrete points of the blade cross-section line into the corresponding spatial coordinate point set according to the radial height of the different cross-sections. Convert the coordinates of the discrete points obtained in step S3 on the local planar coordinate XY to the cylindrical surface at the corresponding cross-section height in the three-dimensional XYZ coordinate system. In the three-dimensional XYZ coordinate system, the directions of the X and Y axes are the same as those in the planar coordinate system. Determine the Z axis according to the left-hand rule. After conversion, the x coordinate of the point on the cylindrical surface is the same as the planar coordinate x before conversion, and the transformation formula is derived as follows: x′ = x y′ = R n sinθ z′ = R n cosθ where R n is the radial height where the cross-section is located, θ = arctan(y / R n ), and θ is the angle between the coordinate point and the Z-axis; S5. Translate the different cross-sections according to the stacking deformation law to generate multiple guide lines and obtain the spatial coordinate point set of the multiple guide lines; S6. In the STARCCM+ three-dimensional design function, import the spatial coordinate point sets of the root cross-section, the tip cross-section, and the multiple guide lines to generate an initial fan model and record a macro file; S7. Run the macro file in STARCCM+ to obtain the three-dimensional model of the parameterized initial fan.

2. A three-dimensional model building method for a cooling fan based on STARCCM+ software according to claim 1, characterized in that: In the step S1, the fan includes an open fan and a ring fan. For the open fan, the basic shape parameters include the fan radius R t , the hub radius R b , the number of blades Q, and the hub height H1. For the ring fan, the basic shape parameters further include the blade ring width W and the blade ring height H2.

3. A three-dimensional model modeling method of a cooling fan based on STARCCM+ software according to claim 2, characterized in that, The specific content of step S2 is as follows: S21. Set N blade cross-sections, and the radial height difference Δr between adjacent cross-sections is Δr = (R t - R b ) / (N - 1), where R t is the radius of the fan, and R b is the radius of the hub; S22. Draw a cylindrical section in the original fan model according to the calculated radial height difference of the section to obtain the blade section line and the mean camber line at the corresponding height; taking the leading edge end point of the mean camber line of each section as the origin, and taking the fan axial direction and the circumferential tangent direction where the leading edge end point is located as the X and Y axes respectively, establish a local plane coordinate system, expand each cylindrical section line and the mean camber line onto the XY plane of the local plane coordinate system, and then measure the mean camber line on each XY plane in turn to obtain the blade characteristic parameters of the corresponding section. The blade characteristic parameters include the leading edge airflow angle θ1, the trailing edge airflow angle θ2, the chord length L, the installation angle λ, and the section thickness t.

4. A three-dimensional model modeling method of a cooling fan based on STARCCM+ software according to claim 3, characterized in that, The specific content of step S5 includes the following: S51. By applying different XY translation amounts to each section, different stacking forms of the blade can be realized, including the bending shapes and degrees in different directions. S52. In the set of discrete point spatial coordinates of each section generated in step S4, select multiple discrete points with the same number on the suction surface, pressure surface, leading edge end surface, and trailing edge end surface respectively as the guide line feature points and mark them with the serial numbers of the discrete points on the corresponding surfaces. Extract the points with the same serial number of each section in the same direction in turn to form a guide line coordinate set, and generate multiple guide line coordinate sets.

5. A three-dimensional model modeling method of a cooling fan based on STARCCM+ software according to claim 4, characterized in that, The specific content of applying different XY translation amounts to each section includes the following: The method based on the original fan model is that for the multiple sections intercepted in step S22, taking one section as the reference section to establish a local plane coordinate system, and expanding and projecting all the other sections onto the XY plane of the local plane coordinate system. By measuring the xy coordinate differences of the leading edge airflow angle end points between other sections and the reference section, the offset amounts of all sections relative to the reference section can be obtained.

6. The 3D model building method of a cooling fan based on STARCCM+ software according to claim 5, characterized in that The specific content of step S6 includes the following: S61. Enter the STARCCM+ 3D-CAD design function, turn on the macro recording function to start recording the operation process, create multiple 3D sketches. The number of 3D sketches is equal to the sum of the hub section, the tip section, and the number of guide lines. Import the hub section, the tip section, and all the guide lines into the 3D sketches respectively to generate a blade model, and then generate Q blade models through the array function. S62. Draw a hub on the XZ plane, generate a hub model with a height of H1 through the rotation function. For the annular fan, a shroud model also needs to be generated according to the shroud width W and the shroud height H2. After completion, perform a Boolean operation on all the models to obtain the original fan three-dimensional model and save the macro file.

7. A three-dimensional model building method for a cooling fan based on STARCCM+ software according to claim 1, characterized in that, The solid modeling method further includes: Define the characteristic parameters in the macro file in step S6 as functions and point to the prepared spreadsheet. Fill the modified fan design parameter data into the corresponding positions in the spreadsheet to obtain the modified macro file. Run the modified macro file in STARCCM+ to obtain the three-dimensional model of the fan with modified parameters.

8. An electronic device, characterized in that, Including: One or more processors; A memory for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement any one of the three-dimensional model modeling methods of the cooling fan based on STARCCM+ software as described in claims 1-7.

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