A multi-leaf multi-period high-precision modeling method for a blade mechanical runner

Abstract

The application discloses a kind of multi-leaf row multi-period high-precision modeling method for blade mechanical runner, corresponding curve is generated by fitting hub and casing value point set, and hub or casing surface is generated by using sweep operation.Adjust the intersection detection and correction strategy of blade root or blade tip section, discrete blade root, blade tip and the curve of blade back and blade basin in spanwise middle, the average value of discrete point set is obtained to obtain approximate middle camber line point set.New points are inserted at the beginning and end of approximate middle camber line point set, and smoothing treatment is carried out, to obtain the cross-sectional curve point set of rotary surface.The intersection detection and correction strategy is used to adjust the cross-sectional curve point set of rotary surface at the blade root and blade tip blade type section, and the rotary surface is generated by using lofting operation.The rotary surface is cut by using hub and casing surface, and the cutting surface between blades is accurately calculated by using automatic algorithm to further cut the rotary surface.The arbitrary period sub-runner section is generated by rotating or translating sweep, and the final fluid passage model is obtained by performing Boolean operation with three-dimensional blade.

Description

Technical Field

[0001] The present invention relates to the field of modeling technology, and in particular to a multi-row, multi-cycle, high-precision modeling method for a blade mechanical flow channel. Background Art

[0002] Aerodynamic simulation of compressors and turbines is a crucial step in engine design. Accurate modeling of blades and flow paths directly impacts the accuracy of aerodynamic simulation. Currently, parametric blade modeling has been extensively researched and yields extensive experience. A common method for generating three-dimensional blade profiles is to fit the blade profile points with spline curves to obtain the blade base and blade back curves, and then use lofting operations between the blade profile sections to generate a high-precision blade model. However, in blade aerodynamic simulation, the design and modeling of the flow paths are equally crucial.

[0003] The definition of a flow channel is the gas portion of the flow path between the hub and the casing, excluding the blade geometry. By applying experimental conditions to the inlet and outlet of the flow channel, the movement of the gas under the action of the blade can be calculated through numerical simulation, thereby comprehensively evaluating the blade design and predicting the maximum compression ratio, the conditions for surge, the flow separation position on the blade surface, the location of shock waves, etc.

[0004] There are two mainstream methods for generating 3D flow paths. The first method is closely integrated with the mesh generation process. First, a spline curve is used to fit the hub and casing's profile points to obtain the meridian profile curves and clip the inlet and outlet. These curves are then discretized again, and the distribution of points on the meridian profile is adjusted using a density control rule. The internal mesh points of the meridian flow surface are then obtained through linear interpolation. Given a given number of circumferentially discrete points in the 3D flow path, the meridian flow surface containing the grid points is evenly distributed circumferentially to obtain a hexahedral mesh of the 3D flow path without blades. After mapping the meridian flow surface grid points onto the blade surface, the discretized blades are inserted into the 3D flow path. The grid points are further adjusted based on the density control of the blade surface and normal grid points to obtain a hexahedral mesh containing only the aerodynamic portion of the flow. The mesh between the blades is then partitioned according to a specific mesh partitioning strategy, and the mesh is finally adjusted using elliptic equations. Finally, a periodic flow path mesh is extracted to obtain a 3D flow path that meets periodicity requirements and is suitable for numerical simulation of blade aerodynamics. This method directly generates a mesh suitable for numerical calculations based on the meridional flow path and blade profile points, but does not output a 3D model of the flow path or blades. The final aerodynamic flow path shape is entirely dependent on the mesh partitioning strategy used in mesh generation. This method has the advantage of being highly universal and capable of automatically and quickly generating a computationally viable mesh, but the controllability of the flow path shape is limited.

[0005] Another 3D flow channel generation method relies on manual modeling to directly generate a 3D flow channel model suitable for mesh generation. Specifically, after generating a 3D blade in 3D modeling software such as UG, SolidWorks, or CATIA, a simple surface is created to enclose the blade by estimating its shape, or the blade base or blade back surface is directly magnified to serve as a surface of revolution. The swept hub and casing surfaces are then clipped to obtain their contours. A rotational sweep operation is then performed on the clipped surface of revolution to create a 3D flow channel solid for the blade segment. Finally, an extrusion operation is performed on the inlet and outlet planes of the 3D flow channel solid to generate long, straight inlet and outlet sections. These sections are then merged with the blade segment to create the final 3D flow channel solid. For multi-blade rows, a plane is manually created between the two blades. The outlet section of the preceding sub-channel segment is clipped with the inlet section of the following sub-channel segment using the plane, generating a precisely matched dynamic and static interference surface between the two sub-channel segments. The generation of multi-periodic flow channels is based on the arraying or copying and rotating of single flow channels and then merging them.

[0006] The flow channel modeling process based on the above-mentioned 3D modeling software not only requires manual intervention at every step but also contains numerous fundamental errors. First, the generation process of the surface of revolution requires constant manual adjustment, making it difficult to ensure that the 3D flow channel generated by sweeping the surface of revolution can completely enclose the blade, especially when encountering complex blades with large radial curvature. If the surface of revolution does not fit the blade well, since the number of blade periods is fixed, when sweeping the angle or distance of one period, the blade may be inserted outside the flow channel. Second, the practice of directly performing translational sweeping on the inlet and outlet surfaces of the blade segment to obtain the inlet and outlet sections and then merging them not only causes the meridian flow path profiles of the inlet and outlet sections of the flow channel to completely lose alignment with the contours of the hub and casing, but also causes the connection between the inlet and outlet sections and the blade segment to be rough and without smooth transitions. When generating the mesh, the connection is prone to generating a highly skewed mesh, which is not conducive to the accurate transmission of periodic boundary information during simulation calculations. Furthermore, simply merging the inlet and outlet sections with the blade segments can lead to redundant lines and surfaces on the geometric surfaces and at internal connections, resulting in geometric discontinuities. These extra lines and surfaces often require complex processing during mesh generation to ensure mesh continuity. Furthermore, when generating sub-channel segments for multi-blade rows, the practice of directly using a plane to clip adjacent sub-channel segments to obtain dynamic and static interference surfaces is not applicable to turbomachinery or planar blade cascades. When the clipping plane does not meet the unique conditions of being perpendicular to the rotation axis (z-axis) and parallel to the rotation plane (xy-plane), the sub-channel segments generated by clipping do not meet the periodicity requirements during rotation and translation, and the dynamic and static interference surfaces between the sub-channel segments do not precisely match during rotation or translation. Finally, when generating multi-periodic channels, directly merging or arraying a single-periodic channel after rotation and duplication can result in duplicate edges and faces, which increases the difficulty of handling dirty geometry. Due to precision errors in commercial geometry software, especially when the rotation axis of the blade or sub-channel segment does not coincide with the z-axis, the geometry after rotation or array generation will have slight bumps at the connection. The contours of the sub-channel segment hub and the casing cannot achieve a smooth connection and transition, and the outlet and inlet planes between adjacent periods of the sub-channel segment do not completely coincide, resulting in bumps.

[0007] The above flow channel geometry modeling and design problems lead to large errors between the aerodynamic simulation results and the experimental results of the blades. Therefore, it is urgent to solve the problem of automated modeling of multi-periodic and multi-blade exhaust aerodynamic flow channels of impeller machinery and planar blades, ensure the geometric accuracy of the dynamic and static interference surfaces and periodic surfaces of the sub-flow channel sections, reduce manual intervention, and improve the efficiency and accuracy of aerodynamic simulation. Summary of the Invention

[0008] Aiming at the current poor modeling accuracy of impeller mechanical and plane cascade aerodynamic simulation model, unable to control the shape and length of the flow passage, unable to restore the real working condition of the blade, and the difficulty problem of needing a lot of human intervention, the present application provides a kind of multi-blade row multi-period high-precision modeling method for blade mechanical flow passage.The method generates corresponding curves by fitting hub and casing type value point set, and generates hub or casing surface by using sweeping operation.Adjust the blade root or tip section by using intersection detection and correction strategy, discrete blade root, tip and spanwise middle blade back and blade basin curve, and obtain the approximate camber line point set by averaging the discrete point set.Insert new points at the beginning and end of the approximate camber line point set and perform smoothing processing to obtain the rotary surface section curve point set.Adjust the rotary surface section curve point set at the blade root and tip section by using intersection detection and correction strategy, and generate the rotary surface by using lofting operation.Cut the rotary surface using the hub and casing surface, and further cut the rotary surface by calculating the cutting surface between the blades.Obtain the final fluid passage model by rotating or translating the sweeping operation and performing Boolean operation with the three-dimensional blade.The method can generate high-precision sub-flow passage segments with completely coinciding dynamic interference surfaces and completely consistent periodic surfaces for single-blade row or multi-blade row impeller machines or plane cascades, and improve the accuracy of numerical simulation.

[0009] The technical scheme adopted by the present application is: a kind of multi-blade row multi-period high-precision modeling method for blade mechanical flow passage, comprising:

[0010] S1: fit the hub and casing type value point set to obtain the hub and casing curve, and generate the hub or casing surface by using sweeping operation according to the blade type;

[0011] S2: detect whether the blade root or tip section in the blade type section exists intersection with the hub or casing surface, and adjust the blade back and blade basin type value point set of the blade root or tip section in the blade type section according to the intersection condition, fit the blade back and blade basin type value point set of the blade root, blade spanwise middle and tip to obtain the blade back and blade basin curve at the three blade type sections;

[0012] S3: respectively distance the blade back and blade basin curve at the three blade type sections to obtain the blade back and blade basin curve point set, average the points at corresponding positions in the blade back and blade basin line point set to obtain the approximate camber line point set, insert points at the beginning and end of the approximate camber line point set and align the beginning point and end point to obtain the rotary surface section curve point set, adjust the coordinates of the points in the rotary surface section curve point set by using smoothing algorithm, and complete the smooth extension of the approximate camber line to the outlet and inlet directions;

[0013] S4: detect whether the rotary surface section curve point set at the blade root or tip blade type section exists intersection with the hub or casing surface, and adjust the coordinates of the rotary surface section curve point set at the blade root or tip blade type section according to the intersection condition;

[0014] S5: fitting the revolution surface section curve point sets at the three blade sections to obtain revolution surface section curves, performing a lofting operation between the revolution surface section curves to generate a revolution surface, and clipping the revolution surface using the hub or casing surface;

[0015] S6: For each blade, repeat the operations in S1-S6 to obtain the rotation surface of each blade;

[0016] S7: Calculate the outlet or inlet clipping lines between adjacent revolution surfaces, as well as the inlet clipping line of the first revolution surface and the outlet clipping line of the last revolution surface. Magnify the clipping lines by a certain multiple relative to their geometric centers. Use different sweep operations on the clipping lines according to the blade type to generate clipping surfaces. Traverse all revolution surfaces and use the corresponding clipping surfaces to clip the revolution surfaces to obtain the clipped revolution surfaces. Create a meridian flow surface and clip it to obtain the flow channel inlet surface and flow channel outlet surface.

[0017] S8: traverse all the trimmed revolution surfaces, and according to the blade type, use a sweep operation to sweep the corresponding single-cycle or multi-cycle angle or distance for each revolution surface to generate a sub-flow channel segment;

[0018] S9: For each blade, a lofting operation is used between the blade section sets to generate a three-dimensional blade. According to the number of periods of the sub-channel segments, a Boolean operation is performed between each of the sub-channel segments and its corresponding three-dimensional blade. The corresponding three-dimensional blade is subtracted from the sub-channel segment to generate multiple single-period or multi-period fluid channels.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The method of the present application can effectively solve the problems existing in the modeling of blade mechanical flow channels. It introduces the type value point set of the blade back and blade basin of the blade section, as well as the intersection detection and correction strategy of the curve point set of the rotation surface section to ensure that the Boolean operation between the three-dimensional blade and the sub-flow channel segment is carried out smoothly, and at the same time ensures that the Boolean operation between the sub-flow channel segment and the hub and casing wall is carried out smoothly, thereby obtaining accurate wall boundary information. The degree of freedom of control of the shape and length of the fluid channel is increased, and the algorithm is used to automatically generate the cutting surface between the blades to ensure the matching accuracy of the fluid channel at the interface. By performing rotational sweeping or translational sweeping on the cutting rotation surface, the accuracy of the periodic surface matching is further guaranteed, avoiding common geometric errors. Boolean operation operations are performed between the sub-flow channel segment and the three-dimensional blade to achieve accurate modeling of multi-blade row and multi-periodic fluid channels. In addition, the entire modeling process is highly automated, reducing manual intervention, making the modeling of the fluid channel more in line with engineering requirements, improving the accuracy and stability of mesh generation and numerical simulation, and having high practical value and application prospects.

[0021] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0023] Figure 1 The present invention is a flowchart showing a method for high-precision modeling of multi-row and multi-cycle blade mechanical flow channels according to an exemplary embodiment.

[0024] Figure 2 It is a schematic diagram of the hub and casing type value point set and the hub and casing curve obtained after fitting of the hub and casing type value point set of a single-stage axial flow compressor blade group, compressor blade and plane blade grid according to an exemplary embodiment.

[0025] Figure 3 It is a schematic diagram showing a single-stage axial compressor blade group, a rotational sweep of a compressor blade hub and a casing curve, and a translational sweep of a planar blade hub and a casing curve according to an exemplary embodiment.

[0026] Figure 4 It is a schematic diagram showing the discrete process of the hub and casing curves of a single-stage axial flow compressor blade group, compressor blades and a planar cascade according to an exemplary embodiment.

[0027] Figure 5 It is a schematic diagram of a partially enlarged view of the shape value point set of the blade root section, blade back and blade basin and the hub curve point set of the guide vane in the blade group of a single-stage axial flow compressor according to an exemplary embodiment.

[0028] Figure 6 It is a schematic diagram showing the distribution and correction strategy of the shape value point set and hub curve point set of the blade root section, blade basin and blade back of the guide vane in the single-stage axial flow compressor blade group according to an exemplary embodiment.

[0029] Figure 7 It is a schematic diagram of a partially enlarged view of the shape value point set and the casing curve point set of the blade tip section, blade back and blade basin of the guide vane in the single-stage axial flow compressor blade group according to an exemplary embodiment.

[0030] Figure 8 It is a schematic diagram showing the distribution and correction strategy of the shape value point set and casing curve point set of the blade tip section, blade basin and blade back of the guide vane in the single-stage axial flow compressor blade group according to an exemplary embodiment.

[0031] Figure 9The present invention is a schematic diagram showing the process of fitting the blade back and blade basin curves of the blade profile cross section at the blade root, the middle of the blade span and the blade tip of the support plate, guide vane, rotor and stator in a single-stage axial compressor blade group according to an exemplary embodiment.

[0032] Figure 10 The present invention is a schematic diagram showing the discrete process of blade back and blade basin curves at three blade profile sections of the support plate, guide vane, rotor and stator in a single-stage axial flow compressor blade group according to an exemplary embodiment.

[0033] Figure 11 The present invention is a schematic diagram showing a process of obtaining approximate mid-arc point sets at three blade profile sections of a support plate, a guide vane, a rotor, and a stator in a single-stage axial compressor blade assembly according to an exemplary embodiment.

[0034] Figure 12 The present invention is a schematic diagram showing a comparison between a spline curve generated by fitting a set of rotational surface cross-section curve points of three cross-sections of a support plate, a guide vane, a rotor, and a stator in a single-stage axial compressor blade assembly and an approximate mid-arc line point set according to an exemplary embodiment.

[0035] Figure 13 The figure is a schematic diagram showing a comparison between a spline curve generated by fitting a point set of a surface of revolution cross-section curve of three cross-sections of a planar cascade and an approximate mid-arc point set according to an exemplary embodiment.

[0036] Figure 14 The present invention is a schematic diagram showing a comparison of spline curves generated by fitting a set of points of a cross-section curve of a single-stage axial compressor blade assembly with aligned and misaligned head and tail points of a support plate, guide vane, rotor, stator, and plane blade cascade according to an exemplary embodiment.

[0037] Figure 15 The figure is a schematic diagram showing a comparison of spline curves generated by fitting a smoothed and unsmoothed surface of revolution cross-section curve point set according to an exemplary embodiment.

[0038] Figure 16 It is a schematic diagram of a partially enlarged view of a rotational surface cross-section curve point set and a hub curve point set at a blade root airfoil section according to an exemplary embodiment.

[0039] Figure 17 The diagram is a schematic diagram showing the distribution of a rotational surface cross-section curve point set and a hub curve point set at a blade root profile section of a guide vane of a single-stage axial flow compressor blade assembly according to an exemplary embodiment.

[0040] Figure 18 The present invention is a schematic diagram showing the comparison before and after intersection detection and correction of a set of rotational surface cross-section curve points at the blade root and blade tip airfoil sections of each blade in a single-stage axial compressor blade group according to an exemplary embodiment.

[0041] Figure 19 It is a schematic diagram of a partially enlarged view of a rotational surface cross-section curve point set and a casing curve point set at a blade profile section of a guide vane tip of a single-stage axial compressor blade group according to an exemplary embodiment.

[0042] Figure 20 The diagram is a schematic diagram showing the distribution of a rotational surface cross-section curve point set and a casing curve point set at a blade tip section of a guide vane of a single-stage axial compressor blade group according to an exemplary embodiment.

[0043] Figure 21 The present invention is a schematic diagram showing a process of generating a surface of revolution by using a lofting operation between cross-sectional curves of a single-stage axial compressor blade group and a planar blade cascade according to an exemplary embodiment.

[0044] Figure 22 The figure is a schematic diagram showing a process of generating the rotating surfaces of the support plate, guide vanes, rotor and stator in a single-stage axial compressor blade assembly according to an exemplary embodiment.

[0045] Figure 23 The present invention is a schematic diagram showing a process of cutting the rotating surfaces of the support plate, guide vanes, rotor and stator of a single-stage axial compressor blade assembly using the hub and casing curved surfaces according to an exemplary embodiment.

[0046] Figure 24 The diagram is a schematic diagram showing the cutting lines between blades of a single-stage axial compressor blade group, the inlet cutting line of the first rotating surface, and the outlet cutting line of the last rotating surface according to an exemplary embodiment.

[0047] Figure 25 FIG. 4 is a schematic diagram showing all trimmed surfaces of a single-stage axial flow compressor blade assembly according to an exemplary embodiment.

[0048] Figure 26 The figure is a schematic diagram showing the inlet and outlet trimming process of the rotating surface of the blade group of a single-stage axial flow compressor according to an exemplary embodiment.

[0049] Figure 27 The figure is a schematic diagram showing a process of obtaining the flow passage inlet surface and the flow passage outlet surface of a blade assembly of a single-stage axial flow compressor according to an exemplary embodiment.

[0050] Figure 28 The figure is a schematic diagram showing a process of generating a single-period sub-flow passage segment of a single-stage axial flow compressor blade group, compressor blades, and a planar cascade according to an exemplary embodiment.

[0051] Figure 29The present invention is a schematic diagram showing a process of generating multi-periodic sub-flow passage segments of a single-stage axial compressor blade group, compressor blades, and a planar cascade according to an exemplary embodiment.

[0052] Figure 30 The figure is a schematic diagram showing a process of generating an inlet section and an outlet section of a blade assembly flow passage of a single-stage axial compressor according to an exemplary embodiment.

[0053] Figure 31 The diagram is a schematic diagram of a three-dimensional blade generation process for a single-stage axial flow compressor blade group, compressor blades, and a planar cascade according to an exemplary embodiment.

[0054] Figure 32 The figure is a schematic diagram showing a process of generating a single-period sub-flow passage segment of a single-stage axial flow compressor blade group, compressor blades, and a planar cascade according to an exemplary embodiment.

[0055] Figure 33 3 is a schematic diagram of a multi-periodic sub-flow channel segment generation process of a compressor blade ①, a planar cascade ②, and a single-stage axial flow compressor blade group ③ according to an exemplary embodiment. DETAILED DESCRIPTION

[0056] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0057] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. As used in this application and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0058] This application provides a high-precision multi-blade flow channel automatic modeling method for impeller machinery or plane blade cascade fluid simulation. The applicable flow channel shape data structure includes the hub and casing contours saved in the form of shape value points, and the blade shape data structure includes the blade basin and blade back contours saved in the form of shape value points. Here, a single-stage axial flow compressor blade group, compressor blade and plane blade cascade model are used as examples to describe this application in detail. Figure 1 A high-precision multi-blade discharge channel modeling method for impeller machinery or planar cascade fluid simulation in this application includes the following sub-steps:

[0059] S1: Fit the hub and casing type value point sets to obtain the hub and casing curves, and use the sweep operation to generate the hub or casing surface according to the blade type; this step includes the following sub-steps:

[0060] S11: Use spline curves to fit the hub and casing type value point sets respectively to obtain hub and casing curves;

[0061] Specifically, if Figure 2 The hub and casing type value point sets of the single-stage axial compressor blade group ①, compressor blades ②, and planar cascade ③ are shown in the hub and casing curves obtained after fitting. Using spline curves to fit the hub and casing type value point sets can obtain smooth, continuous, and high-precision hub and casing curves.

[0062] This step is designed to obtain the hub and casing curves by fitting the hub and casing model point sets. This step uses spline curve fitting point sets to generate smooth, continuous curves, avoiding the discontinuities or sharp inflection points that may be caused by traditional linear interpolation methods, and more accurately expressing the geometric characteristics of the blade flow path. Compared with methods using multi-segment straight line or circular arc fitting, spline curve fitting can reduce local geometric errors and better capture the true geometry of the hub and casing, thereby improving the overall accuracy of the modeling. It is one of the basic elements to ensure simulation accuracy.

[0063] S12: When the blade type is a rotary machine, the hub and casing curves are rotated and swept 180 degrees to obtain a hub or casing curved surface of the rotary machine;

[0064] Specifically, if Figure 3 The rotational sweep process of the hub and casing curve of the single-stage axial compressor blade group ① or the compressor blade ② is shown as follows. After rotating and sweeping the hub and casing curve by 180°, a partial hub and casing surface can be obtained, which will be used for cutting the rotating surface of the impeller machinery in subsequent operations.

[0065] This step is designed to obtain partial hub and casing surfaces by rotationally sweeping the hub and casing curves. This step can quickly generate regular three-dimensional surfaces, simplifying the modeling process. This method is easy to implement and is suitable for multi-cycle, multi-blade row flow channel design. The surfaces generated by rotational sweeping can maintain the smoothness of the hub and casing curves, ensuring that the generated surfaces have continuity and smooth transitions everywhere, and are suitable for processing blade flow channels with complex contours. When subsequently cutting the revolving surfaces of different blades, it can be ensured that each revolving surface obtains the correct hub and casing contours.

[0066] S13: When the blade type is a planar cascade, the hub and casing curves are simultaneously translated and swept by a certain distance in the positive direction and the negative direction of the blade arrangement direction in the cascade in a Cartesian coordinate system to obtain a hub or casing curved surface of the planar cascade.

[0067] Specifically, as shown in the discrete process of the hub and casing curves of the single-stage axial compressor blade group ①, the compressor blade ② and the hub and casing curves of the planar cascade ③, after the hub and casing curves are scattered into a sufficient number of points at equal intervals, the hub and casing curve point set is obtained and stored again. Figure 3 As shown in the translation sweep process of the hub and casing curves of the mid-plane cascade ③, after the hub and casing curves are translated and swept by a certain distance, a partial hub and casing surface is obtained, which will be used for cutting in the subsequent operation of the planar cascade turning surface.

[0068] This step is designed to obtain a partial hub and casing surface by translating and sweeping the hub and casing curves. The effect of this step is the same as obtaining a partial hub and casing surface by rotating and sweeping the hub and casing curves, both of which are to accurately obtain the hub and casing surface for cutting the turning surface.

[0069] S2: Detect whether the intersection exists between the hub or casing surface and the blade profile section concentrated at the hub or tip section, and adjust the profile point set of the suction surface and the pressure surface of the blade profile section concentrated at the hub or tip section according to the intersection condition, and fit the profile point set of the suction surface and the pressure surface of the blade profile section at the hub, the middle of the blade span and the tip to obtain the suction surface and the pressure surface curves at the three blade profile sections; this step includes the following sub-steps:

[0070] S21: Define the casing as the tip and the hub as the root, scatter the hub and casing curves into a sufficient number of points at equal intervals, and obtain the hub and casing curve point set;

[0071] Specifically, as shown in the discrete process of the hub and casing curves of the single-stage axial compressor blade group ①, the compressor blade ② and the hub and casing curves of the planar cascade ③, after the hub and casing curves are scattered into a sufficient number of points at equal intervals, the hub and casing curve point set is obtained and stored again. Figure 4 This step is designed to scatter the hub and casing curves at equal intervals to obtain the hub and casing curve point set. Discretizing a continuous curve into a finite point set can greatly reduce the step of accurately solving the curve in the intersection detection process. Directly using the point set for intersection detection avoids complex geometric operations, making the whole process more efficient. Solving real points on the curve usually requires the use of iterative methods or precise geometric operations, which is complex and prone to errors. By discretizing into a point set at equal intervals, the intersection detection algorithm can be simplified, the implementation difficulty can be reduced, and the processing of complex numerical solutions or curve equations can be avoided. By setting the interval of the discrete points, the discretization accuracy of the curve can be flexibly controlled. According to the design requirements, a suitable discrete step length can be selected to ensure accuracy and optimize the calculation cost according to the calculation resource limit.

[0072]

[0073] ​S22: traverse the shape value point set of the blade root section, the blade back and the blade basin, calculate the difference between the distance of each shape value point to the z-axis in the Cartesian coordinate system and the radial height of the point closest to the current shape value point in the hub curve point set, and find the maximum and minimum values ​​of the difference during the traversal process;

[0074] Specifically, if Figure 5 As shown in a partially enlarged view of the shape value point set and hub curve point set for the blade root section, blade back, and blade basin of a guide vane in a single-stage axial compressor blade assembly, the algorithm traverses each shape value point on the blade root section, blade back, and blade basin, calculating their distance to the z-axis in the Cartesian coordinate system. Simultaneously, the point in the hub curve point set closest to the current shape value point is found and its distance to the z-axis is calculated. The difference between these two distances is then calculated. During this traversal, the maximum and minimum values ​​of all differences are found for subsequent intersection detection and correction.

[0075] This step is designed to find the maximum and minimum values ​​of the difference between the distance from the point in the type value point set of the blade back and blade basin of the blade root section to the z-axis and the distance from the point in the hub curve point set to the z-axis. This step can clarify the geometric differences between the two sets of point sets by calculating the distance from the type value point and the hub curve point to the z-axis and finding the maximum and minimum values ​​in the difference. The calculation of the maximum and minimum values ​​provides a reliable reference for subsequent intersection detection, making the matching and interaction of curves more accurate. By calculating the distance from each type value point to the z-axis and comparing it with the corresponding hub curve point, it is converted into a simple distance difference operation, avoiding complex geometric solutions. In this way, complex curve fitting problems can be simplified into intuitive distance analysis, making it easier to detect and process curve intersections or deviations.

[0076] S23: Adjust the shape value point set of the blade root section blade basin and blade back according to the following logic:

[0077] (1) Both the maximum and minimum values ​​of the difference are positive: at this time, all the profile points of the blade basin and blade back of the blade root section are within the meridian flow path surrounded by the hub or casing surface. Further judgment is made as to whether the minimum value of the difference is greater than the user-defined blade root clearance value. If so, it indicates that there is a blade root clearance and the radial height of the blade root section is not adjusted. If it is less than the user-defined blade root clearance value, it indicates that there is an error in the blade design and correction is required. The x-coordinates of all the profile points of the blade root section are subtracted by the maximum value of the difference.

[0078] (2) The maximum value of the difference is positive and the minimum value is negative: In this case, some of the profile points on the blade basin or blade back of the blade root section are outside the meridian flow path surrounded by the hub or casing surface, and some are inside the meridian flow path, indicating that there is an error in the blade design and it needs to be corrected. The x-coordinates of all the profile points on the blade root section are subtracted from the maximum value of the difference;

[0079] (3) The maximum and minimum values ​​of the difference are both negative: At this time, all the shape value points of the blade root section, blade back and blade basin are outside the meridian flow path surrounded by the hub or casing surface, indicating that the blade design is correct and no correction is required;

[0080] (4) If the minimum difference between the blade root section and the casing is positive and greater than the user-defined blade root clearance value, it indicates that there is an uncorrectable error in the blade design, and the subsequent process is terminated;

[0081] In the impeller machinery, the calculation formula for the distance difference is:

[0082]

[0083] In a plane cascade, the distance difference is calculated as:

[0084] d=P x -x target ;

[0085] Where P(x, y, z) is the coordinate of the point of the concentrated value of the blade root or blade tip section, blade back or blade basin in the Cartesian coordinate system, where the x coordinate represents the radial height, x represents the radial height, and target The radial height of the hub or casing value point closest to the current value point;

[0086] Specifically, if Figure 6 The distribution of the shape value point set of the blade basin and blade back of the guide vane in the blade group of a medium single-stage axial compressor and the hub curve point set is shown as follows. In the first case ①, the shape value point set of the blade basin and blade back of the blade root section and the hub curve point set do not intersect in distribution, and all shape value points are within the meridian flow path surrounded by the hub or casing surface. At this time, the absolute value of the minimum difference is less than the user-defined blade root clearance value, indicating that there is an error in the blade design and needs to be corrected. The x-coordinates of all shape value points in the blade root section are subtracted from the maximum difference to obtain the corrected blade root section; in the second case ②, the shape value point set of the blade basin and blade back of the blade root section and the hub curve point set do not intersect in distribution, and all shape value points are within the hub or casing surface. Within the meridian flow path surrounded by the casing surface, the absolute value of the minimum difference is greater than or equal to the user-defined blade root clearance value, indicating that there is no error in the blade design and no correction is required; in the third case ③, the shape value point set of the blade basin and blade back of the blade root section intersects with the hub curve point set in distribution, indicating that there is an error in the blade design and correction is required. The corrected blade root section is obtained by subtracting the maximum value of the difference from the x-coordinate of all shape value points in the blade root section; in the fourth case ④, the shape value point set of the blade basin and blade back of the blade root section does not intersect with the hub curve point set in distribution, and all shape value points are outside the meridian flow path surrounded by the hub or casing surface, indicating that there is no error in the blade design and no correction is required.

[0087] This operation is designed to detect the geometric distribution relationship between the profile point set of the blade root section's blade basin and blade back and the hub curve point set, and to judge the correctness of the blade design according to different situations, thereby guiding the correction of the blade root section profile point set. This step calculates the geometric difference between the blade root profile point set and the hub curve point set, and judges it based on the preset blade root clearance value. It can accurately identify errors in the blade design and correct the blade root section when necessary. For example, when there is an error in the profile point distribution, the correction is achieved by adjusting the x-coordinates of all profile points to ensure that the blade design meets the geometric accuracy requirements. The operation classifies the relationship between the profile point set and the hub curve point set according to four different situations. By analyzing the extreme values ​​of the difference and the spatial distribution of the point set (such as intersection, wrapping inside or outside the meridian flow path), the relative position relationship between the blade root section and the hub surface can be accurately identified, so that targeted strategies can be adopted to make corrections or determine whether corrections are needed. By precisely adjusting the maximum or minimum difference value, it is possible to ensure that all shape points maintain a consistent geometric relationship in the corrected blade root section, avoiding overall shape deviation due to local adjustments, thereby improving the geometric accuracy of blade modeling and avoiding deterioration in the modeling accuracy of the flow channel.

[0088] S24: traverse the shape value point set of the blade basin and blade back of the blade tip section, calculate the difference between the distance of each shape value point to the z-axis in the Cartesian coordinate system and the radial height of the point closest to the current shape value point in the casing curve point set, and find the maximum and minimum values ​​of the difference in the traversal process;

[0089] Specifically, if Figure 7 As shown in a partially enlarged view of the profile point set and the casing curve point set for the blade tip section, back section, and basin of a guide vane in a single-stage axial compressor blade assembly, the algorithm traverses each profile point on the blade tip section, back section, and basin, calculating their distance to the z-axis in the Cartesian coordinate system. Simultaneously, the point in the casing curve point set closest to the current profile point is found and its distance to the z-axis is calculated. The difference between these two distances is then calculated. During this traversal, the maximum and minimum values ​​of all differences are found for subsequent intersection detection and correction.

[0090] This step is designed to find the maximum and minimum values ​​of the difference between the distance from the point in the type value point set of the blade back and blade basin of the blade top section to the z-axis and the distance from the point in the casing curve point set to the z-axis. This step can clarify the geometric differences between the two sets of points by calculating the distance from the type value point and the casing curve point to the z-axis and finding the maximum and minimum values ​​in the difference. The calculation of the maximum and minimum values ​​provides a reliable reference basis for subsequent intersection detection, making the matching and interaction of curves more accurate. By calculating the distance from each type value point to the z-axis and comparing it with the corresponding casing curve point, it is converted into a simple distance difference operation, avoiding complex geometric solutions. In this way, the complex curve fitting problem can be simplified to an intuitive distance analysis, making it easier to detect and process the intersection or deviation of the curves.

[0091] S25: Adjust the shape value point set of the blade top section, blade basin and blade back according to the following logic:

[0092] (1) The maximum and minimum values ​​of the difference are both positive: At this time, all the shape value points of the blade tip section, blade back and blade basin are outside the meridian flow path surrounded by the hub or casing surface, indicating that the blade design is correct and no correction is required;

[0093] (2) The maximum value of the difference is positive and the minimum value is negative: In this case, some of the profile points of the blade basin or blade back of the blade tip section are outside the meridian flow path surrounded by the hub or casing surface, and some are inside the meridian flow path, indicating that there is an error in the blade design and it needs to be corrected. The x-coordinates of all the profile points of the blade tip section are added to the absolute value of the minimum value of the difference;

[0094] (3) Both the maximum and minimum values ​​of the difference are negative: At this time, all the profile points of the blade basin and blade back of the blade tip section are within the meridian flow path surrounded by the hub or casing surface. Further judge whether the absolute value of the maximum value of the difference is greater than the user-defined blade tip clearance value. If so, it indicates that there is a blade tip clearance and the blade tip section radial height is not adjusted. If it is less than the user-defined blade tip clearance value, it indicates that there is an error in the blade design and needs to be corrected. The x-coordinates of all the profile points of the blade tip section are added with the absolute value of the minimum value of the difference.

[0095] (4) If the maximum difference between the tip section and the casing is negative and its absolute value is greater than the user-defined tip clearance value, it means that there is an uncorrectable error in the blade design, and the subsequent process is terminated;

[0096] In the impeller machinery, the calculation formula for the distance difference is:

[0097]

[0098] In a plane cascade, the distance difference is calculated as:

[0099] d=P x -xtarget ;

[0100] Where P(x, y, z) is the coordinate of the point of the blade tip or blade tip section blade back or blade basin in the Cartesian coordinate system, where the x coordinate represents the radial height, x represents the radial height, and target The radial height of the hub or casing value point closest to the current value point;

[0101] Specifically, if Figure 8 The distribution of the profile point set of the blade basin and blade back of the guide vane in the blade group of a medium single-stage axial compressor and the casing curve point set is shown as follows. In the first case ①, the profile point set of the blade basin and blade back of the blade top section and the casing curve point set do not intersect in distribution, and all profile points are within the meridian flow path surrounded by the hub or casing surface. At this time, the maximum value of the difference is less than the user-defined blade tip clearance value, indicating that there is an error in the blade design and it needs to be corrected. The x-coordinates of all profile points in the blade top section are subtracted from the maximum value of the difference to obtain the corrected blade tip section; in the second case ②, the profile point set of the blade basin and blade back of the blade top section and the casing curve point set do not intersect in distribution, and all profile points are within the hub or casing surface. Within the meridian flow path surrounded by the casing surface, the maximum value of the difference at this time is greater than or equal to the user-defined tip clearance value, indicating that there is no error in the blade design and no correction is required; in the third case ③, the shape value point set of the blade basin and blade back of the blade tip section intersects with the casing curve point set in distribution, indicating that there is an error in the blade design and needs to be corrected. The corrected blade tip section is obtained by subtracting the maximum value of the difference from the x-coordinate of all shape value points in the blade tip section; in the fourth case ④, the shape value point set of the blade basin and blade back of the blade tip section does not intersect with the casing curve point set in distribution, and all shape value points are outside the meridian flow path surrounded by the hub or casing surface, indicating that there is no error in the blade design and no correction is required.

[0102] This operation is designed to detect the geometric distribution relationship between the type value point set of the blade basin and blade back of the blade tip section and the casing curve point set, and to judge the correctness of the blade design according to different situations, thereby guiding the correction of the type value point set of the blade tip section. The effect achieved by this step is the same as the intersection detection and correction between the type value point set of the blade basin and blade back of the blade root section and the hub curve point set, but the geometric distribution relationship between the type value point set of the blade basin and blade back of the blade tip section and the casing curve point set is logically distinguished. By processing the relationship between the blade tip section and the casing curve separately, the blade tip and blade root sections are detected separately, which is more logically clear and convenient for designing different detection and correction algorithms. In this way, when the blade tip and blade root have different geometric relationships, the required correction measures can be quickly determined, and the program implementation is more modular, easy to maintain and optimize.

[0103] S26: Fitting the profile value point sets of the suction side and the pressure side of the blade profile sections at the blade root, the blade spanwise middle part and the blade tip of the three blade profile sections to obtain the suction side and pressure side curves at the three blade profile sections.

[0104] Specifically, as shown in the fitting process of the suction side and pressure side curves of the blade profile sections at the blade root, the blade spanwise middle part and the blade tip of the three blade profile sections in the single-stage axial flow compressor blade set, the profile value point sets of the suction side and the pressure side of the blade profile sections at the blade root, the blade tip and the blade spanwise middle part after the intersection detection and correction are fitted using the spline curve to obtain the suction side and pressure side curves at the three blade profile sections, which are used to obtain the approximate camber line point set in the subsequent operation. Figure 9

[0105] This step is to fit the profile value point sets of the suction side and the pressure side of the blade root, the blade tip and the blade spanwise middle part after the intersection detection and correction using the spline curve to obtain the suction side and pressure side curves at the three blade profile sections, which are used to design the subsequent approximate camber line point set. This step can generate smooth and continuous suction side and pressure side curves through spline curve fitting, ensuring the accuracy of the geometric shape. This is particularly crucial for the subsequent calculation of the approximate camber line point set. The fitted curve provides a continuous and smooth input for the subsequent geometric processing, greatly simplifying the subsequent processing steps.

[0106] S3: The suction side and pressure side curves at the three blade profile sections are scattered into suction side and pressure side curve point sets at equal distances, respectively. The approximate camber line point set is obtained by averaging the points at corresponding positions in the suction side and pressure side line point set. The turning surface section curve point set is obtained by inserting points at the head and tail of the approximate camber line point set and aligning the head point and the tail point. The coordinates of the points in the turning surface section curve point set are adjusted using a smoothing algorithm to complete the smooth extension of the approximate camber line in the outlet and inlet directions. This step includes the following sub-steps:

[0107] S31: The suction side and pressure side curves at the three blade profile sections are scattered into suction side and pressure side curve point sets at equal distances, respectively. The number of discrete points of the suction side and the pressure side must be the same, which can be defined by the user.

[0108] Specifically, as shown in the scattering process of the suction side and pressure side curves at the three blade profile sections in the single-stage axial flow compressor blade set, the three blade profile sections are scattered into suction side and pressure side curve point sets with the same number of discrete points at equal distances after being fitted using the spline curve. The number of discrete points in the suction side and pressure side curve point set can be given by the user, but the more the number of discrete points, the more accurate the approximate camber line point set obtained in the subsequent operation. Figure 10

[0109] ​​This step is designed to evenly distribute the blade back and blade base curves at the three blade sections obtained through spline fitting into blade back and blade base curve point sets with the same number of discrete points. By evenly distributing the blade back and blade base curves and unifying the number of discrete points, this step ensures that the subsequent approximate mid-arc point set calculation is uniformly distributed and highly accurate. A greater number of discrete points results in a more accurate approximate mid-arc point set.

[0110] S32: averaging the corresponding points in the leaf basin and leaf back curve point sets in order from the entrance to the exit, and saving them in order to the approximate mid-arc point set;

[0111] Specifically, if Figure 11 The process for obtaining the approximate mid-camber point set for the three blade sections of a single-stage axial compressor blade assembly—the support plate ①, guide vanes ②, rotor ③, and stator ④—is shown. For each pair of corresponding points in the basin-back curve point set (i.e., each basin point and its corresponding back point), a new mid-camber point is obtained by taking the geometric mean. This mean value represents the midpoint between the basin and back in the blade section curve, and the resulting point set is used as part of the approximate mid-camber point set. The corresponding points in the basin-back curve point set for each of the three blade sections are averaged pairwise from inlet to outlet, yielding the approximate mid-camber point set for each of the three sections.

[0112] This step is designed to generate an approximate mid-arc point set by pairwise averaging the corresponding points in the blade basin and blade back curve point sets. This accurately reflects the geometric center position between the blade basin and blade back on the blade cross section, ensuring the smoothness and continuity of the mid-arc line. This step processes the blade basin and blade back point sets point by point through pairwise averaging, using the geometric center point between the blade basin and blade back as the approximate mid-arc line. This ensures that the mid-arc line on each blade cross section is the geometric center point between the blade basin and blade back, ensuring the continuity of the mid-arc line.

[0113] S33: Calculate the difference between the first point and the last point of the approximate mid-arc point set on the z-axis, i.e., the chord length, which is recorded as b and used as the basic unit of extension length;

[0114] Specifically, the first point (i.e., the point near the blade inlet) and the last point (i.e., the point near the blade outlet) are selected from the generated approximate mid-camber point set. The z-axis coordinate difference between these two points is then calculated to obtain the blade's chord length, b. This chord length, b, will serve as an important geometric parameter for subsequent approximate mid-camber extension or shape design adjustments.

[0115] This step is designed to provide a benchmark for subsequent extension or design adjustment of the flow channel shape by calculating the difference between the first point and the last point of the approximate mid-arc point set on the z-axis (i.e., the chord length b). As the basic unit of flow channel shape change, the chord length b enables precise control of the scale and direction of the expansion when extending or adjusting the flow channel, ensuring that the overall proportion of the flow channel design is reasonable. By using the chord length b as a benchmark, the designer can not only ensure that the length extension of the flow channel is consistent with the blade shape when adjusting or optimizing the flow channel shape, but also provide a standardized geometric parameter for the expansion and adjustment of the flow channel shape, making the design steps more organized, reducing unnecessary complexity, and ensuring the consistency and coherence of the flow channel shape.

[0116] S34: Insert a series of new points at the beginning of the approximate arc point set. The insertion formula is as follows:

[0117]

[0118] And insert a series of new points far from the tail of the mid-arc point set. The insertion formula is as follows:

[0119]

[0120] Obtain the final set of revolution surface section curve points;

[0121] in is a series of new points inserted at the head of the approximate mid-arc point set, is a series of new points inserted at the end of the approximate mid-arc point set; n is the number of insertion points; F(x f ,y f , z f ) is the coordinate of the first point in the mid-arc point set sequence, L(x l ,y l , z l ) is the coordinate of the last point in the mid-arc point set sequence; c z_min The minimum z value in the hub and casing type value point coordinate set is when z1-d3·b is less than c z_min When , it means that the last point of the head insertion is outside the flow channel, and it is automatically adjusted to the z value of the meridian flow path entrance coordinate; c z_max The maximum z value in the hub and casing type value point coordinate set is when z2+d6·b is greater than c z_maxWhen , it means that the last point of the tail insertion is outside the flow channel, and it is automatically adjusted to the z value of the meridian flow path outlet coordinate; d1, d2, d3, d4, d5, and d6 are all coordinate adjustment coefficients, among which d1 and d2 are used to determine the position of the first point of the head insertion based on the first point of the approximate mid-arc point set, d3 is used to determine the position of the last point of the head insertion based on the position of the first point of the head insertion of the approximate mid-arc point set, d4 and d5 are used to determine the position of the first point of the tail insertion based on the tail point of the approximate mid-arc point set, and d6 is used to determine the position of the first point of the tail insertion of the approximate mid-arc point set and the position of the last point of the tail insertion. These coordinate adjustment coefficients jointly determine the overall shape and length of the revolving surface and the sub-flow channel segment;

[0122] Specifically, if Figure 12 The figure shows a comparison between the spline curve generated by fitting the curve points of the three sections of the rotating surface of the support plate ①, guide vane ②, rotor ③, and stator ④ in the single-stage axial compressor blade group and the approximate mid-arc point set. In this example, d1 = 0, d2 = 1, d3 = 0, d4 = 0, d5 = 1, d6 = 0, and n = 10. The setting of this set of coordinate adjustment coefficients achieves a temporary extension of the mid-arc in the direction of the inlet tangent and the outlet tangent. This setting is to ensure that the sub-channel section generated in the subsequent steps can include the duct space at the front and rear of the blade. This setting not only provides redundant space during the mesh generation process, facilitating the generation of high-quality meshes at the inlet and outlet, but also allows for more accurate boundary condition settings for the flow at the inlet and outlet away from the blades due to the lack of blade interference, which is conducive to improving the convergence and accuracy of the computational fluid dynamics solution.

[0123] like Figure 13 The following figure compares the spline curves generated by fitting the surface of revolution curve points of three sections of the planar cascade with the approximate mid-camber point set. In this example, d1 = 0, d2 = 1, d3 = 0, d4 = 3, d5 = 0.5, d6 = 0, and n = 10. This set of coordinate adjustment coefficients allows the mid-camber line to be briefly extended toward the inlet tangent. At the outlet, it is initially extended a considerable distance toward the flow direction behind the trailing edge, and then briefly extended toward the outlet tangent. This setting ensures that the sub-channel segment generated in subsequent steps includes the duct space behind the trailing edge in the outlet region, facilitating observation of the flow characteristics, particularly the flow field behavior at the trailing edge of the planar cascade, during subsequent computational fluid dynamics (CFD) solutions and visualizations.

[0124] This step is designed to insert new points at the head and tail of the approximate mid-arc line to achieve a reasonable extension of the mid-arc line toward the inlet and outlet, thereby generating a set of rotation surface section curve points that meet the design requirements and ensure that the subsequent flow channel design can capture the airflow characteristics in front of the leading edge and behind the trailing edge of the blade. This step ensures the integrity and effectiveness of the flow channel design by setting reasonable insertion points. By setting different coordinate adjustment coefficients and controlling the extension direction and length of the mid-arc line, the flow channel design is more in line with the actual airflow conditions, ensuring that the flow channel contains airflow characteristics in the leading and trailing edge areas, facilitating subsequent fluid calculations and analysis, and facilitating designers to observe the flow characteristics behind the trailing edge of the plane blade and obtain key aerodynamic data. This is crucial for studying the airflow characteristics behind the trailing edge of the blade and its impact on the entire flow field.

[0125] S35: Traverse all the points of the cross-section curve of the revolution surface and find the maximum z value z max and the minimum z value z min ; Set the z value of the first point in each revolved surface section curve point set to z min , the z value of the last point is z max ;

[0126] Specifically, if Figure 14 The comparison of the spline curves generated by fitting the rotation surface section curve point sets of the single-stage axial compressor blade group, the support plate ①, the guide vane ②, the rotor ③, the stator ④ and the plane blade ⑤, with the head and tail points aligned and the head and tail points not aligned is shown in the figure. First, all the generated rotation surface section curve point sets are traversed, the z coordinate of each point is recorded, and the maximum and minimum z values ​​of these points are obtained by comparison. min Then, the first point of the curve point set of the revolution surface (i.e., the point where the curve is close to the entrance) is adjusted to ensure that all curves have the same z coordinate at the entrance; similarly, the tail point of the curve (i.e., the point where the curve is close to the exit) is adjusted to z max , ensuring that the z coordinates at the exit are consistent.

[0127] This step is designed to unify the z-coordinate range of all points in the cross-section curves of the revolved surface, ensuring that the z-values ​​of each section at the inlet and outlet are consistent, thereby including the same range of hub and casing surfaces in the flow direction. At the same time, it avoids the different chord lengths of the blade tip, blade root, and blade span-wise mid-section, which would result in the hub and casing geometric areas of the flow channel being too different. It ensures that the mesh units generated on the hub and casing surfaces of the flow channel geometry have similar sizes at all corresponding locations, thereby ensuring that the span-wise mesh has high quality. This step unifies the z-coordinate range of all points in the cross-section curves of the revolved surface, especially at the inlet and outlet, so that the flow channel geometry remains consistent in the hub and casing areas, ensuring that the influence of the flow channel on the flow is correctly restored during the simulation process. This step also helps to generate a more regular and uniform mesh during mesh generation, thereby improving the overall mesh quality. When the geometric differences between the hub and casing surfaces of the flow channel are small, the mesh generation algorithm can more easily generate a high-quality mesh, reducing the difficulty of adjusting the mesh density and size. This not only improves the efficiency of mesh generation, but the consistency and uniformity of the mesh also help reduce numerical errors in the simulation, ensuring that the fluid flow characteristics inside the flow channel can more accurately reflect the actual situation.

[0128] S36: traverse all the points of the cross-section curve of the revolution surface, and adjust the coordinates of the cross-section curve point set of the revolution surface by applying the smoothing algorithm for multiple iterations; for each iteration, the new smoothing point P′ i The coordinate calculation formula is:

[0129]

[0130] where P′ i is the point after smoothing, P1 is the first point before smoothing, P n is the last point before smoothing, P′1=P1, P′ n =P n This means keeping the first and last points unchanged, i=2, 3, ..., n-1.

[0131] Specifically, if Figure 15 The comparison of the spline curves generated by fitting the support plate ①, guide vane ②, rotor ③, stator ④ and plane blade ⑤ of the single-stage axial compressor blade group after smoothing and without smoothing operation shows that after iterative adjustment of the smoothing algorithm, the distribution of the rotation surface cross-section curve point set is smoother, and the transition between the inlet and outlet extension point set and the approximate mid-arc point set is smoother. At the same time, during the smoothing process, the first point P1 and the tail point P n It does not participate in the mean calculation, that is, it remains unchanged, and the boundary characteristics of the curve are retained.

[0132] This step is designed to adjust the coordinates of the point set of the cross-section curve of the surface of revolution through multiple iterations of the smoothing algorithm, thereby improving the smoothness of the curve, ensuring that the cross-section curve of the flow channel is more continuous and smooth in geometry, and avoiding local mutations or irregular changes that have an adverse effect on subsequent mesh generation and fluid simulation. This step eliminates local fluctuations and discontinuities in the cross-section curve of the surface of revolution by smoothing the intermediate points, making the curve smoother and avoiding quality problems caused by curve irregularities during mesh generation, thereby improving the uniformity of the mesh and the accuracy of the simulation calculation. Since the first and last points do not participate in the smoothing adjustment, it can ensure that the starting and ending positions of the curve remain unchanged, retaining the important geometric features of the inlet and outlet in the design, and avoiding unnecessary effects on the overall shape and length of the flow channel. Through multiple iterations, the intensity of the smoothing can be flexibly controlled to adapt to the design requirements of curves of different complexities. Designers can adjust the number of iterations according to actual needs to achieve the desired smoothing effect.

[0133] S4: Detecting whether the revolution surface section curve point set at the blade root or blade tip airfoil section intersects with the hub or casing surface, and adjusting the coordinates of the revolution surface section curve point set at the blade root or blade tip airfoil section according to the intersection situation; this step includes the following sub-steps:

[0134] S41: traversing the revolution surface section curve point set at the blade root blade profile section, calculating the difference between the distance of each point to the z-axis and the radial height of the point closest to the current point in the hub curve point set, and finding the maximum and minimum values ​​of the difference in the iterative process;

[0135] Specifically, if Figure 16 As shown in the partially enlarged image of the revolution surface section curve point set at the mid-blade root profile section and the hub curve point set, the process traverses each point in the revolution surface section curve point set at the blade root profile section, calculating its distance to the z-axis in the Cartesian coordinate system. Simultaneously, the point closest to the current point in the hub curve point set is found and its distance to the z-axis is calculated, followed by the difference between the two distances. During this traversal process, the maximum and minimum values ​​of all the differences are found for subsequent intersection detection and correction.

[0136] This step is designed to find the maximum and minimum values ​​of the difference between the distance from the point in the set of points in the revolving surface section curve at the blade root profile section to the z-axis and the distance from the point in the set of points in the hub curve to the z-axis. This step calculates the distance from the point in the set of points in the revolving surface section curve at the blade root profile section and the hub curve to the z-axis, and finds the maximum and minimum values ​​in the difference, so that the geometric difference between the two sets of points can be clarified. The calculation of the maximum and minimum values ​​provides a reliable reference for subsequent intersection detection, making the matching and interaction of curves more accurate. By calculating the distance from the point in the set of points in the revolving surface section curve at each blade root profile section to the z-axis, and comparing it with the corresponding hub curve point, it is converted into a simple distance difference operation, avoiding complex geometric solutions. In this way, complex curve fitting problems can be simplified into intuitive distance analysis, making it easier to detect and process curve intersections or deviations.

[0137] S42: Adjust the point set of the revolution surface section curve at the blade root profile section according to the following logic:

[0138] (1) Both the maximum and minimum values ​​of the difference are positive: at this time, all points in the set of points of the curve of the surface of revolution at the blade root profile section are within the meridian flow path, and the x-coordinates of all points in the set of points of the curve of the surface of revolution at the blade root profile section are subtracted from the maximum value of the difference;

[0139] (2) The maximum value of the difference is positive and the minimum value is negative: in this case, some points in the set of points of the curve of the surface of revolution at the blade root profile section are outside the meridian flow path, while some points are inside the meridian flow path. The x-coordinates of all points in the set of points of the curve of the surface of revolution at the blade root profile section are subtracted from the maximum value of the difference;

[0140] (3) The maximum and minimum values ​​of the difference are both negative: In this case, all points of the cross section of the rotating surface at the blade root profile section are outside the meridian flow path, and no correction is required;

[0141] The calculation formula of the distance difference is the same as the calculation formula of the distance difference in the intersection detection and correction of the shape value point set of the blade basin and the blade back in the blade root or blade top section.

[0142] Specifically, if Figure 17The distribution of the point set of the meridian surface section curve at the blade root section of the blade set of the single-stage axial compressor and the hub curve point set is shown in the following three cases. In the first case ①, the point set of the meridian surface section curve at the blade root section and the hub curve point set do not intersect in distribution, and all points are within the meridian flow path surrounded by the hub or the casing surface. Correction is needed. The x coordinate of all points of the point set of the meridian surface section curve at the blade root section is reduced by the maximum difference value to obtain the corrected point set of the meridian surface section curve at the blade root section. In the second case ②, the point set of the meridian surface section curve at the blade root section intersects with the hub curve point set in distribution. Correction is needed. The x coordinate of all points of the blade root section is reduced by the maximum difference value to obtain the corrected blade root section. In the third case ③, the point set of the meridian surface section curve at the blade root section and the hub curve point set do not intersect in distribution, and all points are outside the meridian flow path surrounded by the hub or the casing surface. No correction is needed. The intersection detection and comparison before and after correction of the point set of the meridian surface section curve at the blade root section and the hub curve point set of each blade of the single-stage axial compressor blade set are shown in FIGS. 8A to 8C. Figure 18

[0143] The operation is designed to detect the geometric distribution relationship between the point set of the meridian surface section curve at the blade root section and the hub curve point set, and to guide the correction of the point set of the meridian surface at the blade root section according to different cases. The step can accurately identify the error in the design of the point set of the meridian surface section curve at the blade root section by calculating the geometric difference between the points in the point set of the meridian surface section curve at the blade root section and the hub curve point set, and correcting the point set of the meridian surface section curve at the blade root section when necessary, such as adjusting the x coordinate of all points when the point distribution is incorrect, so as to ensure that the meridian surface can be completely trimmed by the hub surface to obtain correct hub profile information. The operation classifies the relationship between the point set of the meridian surface section curve at the blade root section and the hub curve point set according to three different cases. By analyzing the extreme value of the difference and the spatial distribution of the point set (such as intersection, wrapping inside or outside the meridian flow path), the relative position relationship between the point set of the meridian surface section curve at the blade root section and the hub surface can be accurately identified, so that the corresponding strategy is taken for correction or judgment of whether correction is needed. Through accurate adjustment of the maximum or minimum value of the difference, it can be ensured that all points maintain consistent geometric relationship in the corrected point set of the meridian surface section curve at the blade root section, avoiding local adjustment leading to overall shape deviation, and further improving the geometric accuracy of the flow passage modeling.

[0144] S43: Traverse the point set of the meridian surface section curve at the blade tip section, calculate the difference between the distance of each point to the z axis and the radial height of the point in the casing curve point set closest to the current point, and find the maximum and minimum values of the difference in the iteration process;​

[0145] Specifically, if Figure 19 As shown in a partial enlargement of the curve point set of the surface of revolution section and the casing curve point set at the blade tip section of the guide vane of a medium-stage axial compressor, each point on the blade tip section, blade back, and blade basin is traversed, and its distance to the z-axis in the Cartesian coordinate system is calculated. The point closest to the current point in the casing curve point set is found and its distance to the z-axis is calculated, followed by the difference between the two distances. During the traversal process, the maximum and minimum values ​​of all differences are found for subsequent intersection detection and correction.

[0146] This step is designed to find the maximum and minimum values ​​of the difference between the distance from the point in the set of points in the curve of the revolving surface at the blade top profile section to the z-axis and the distance from the point in the set of points in the casing curve to the z-axis. This step can clarify the geometric differences between the two sets of points by calculating the distance from the points in the set of points in the curve of the revolving surface and the casing curve to the z-axis, and finding the maximum and minimum values ​​in the difference. The calculation of the maximum and minimum values ​​provides a reliable reference for subsequent intersection detection, making the matching and interaction of curves more accurate. By calculating the distance from the point in the set of points in the curve of the revolving surface at each blade top profile section to the z-axis, and comparing it with the corresponding casing curve point, it is converted into a simple distance difference operation, avoiding complex geometric solutions. In this way, complex curve fitting problems can be simplified to intuitive distance analysis, making it easier to detect and process curve intersections or deviations.

[0147] S44: Adjust the point set of the revolution surface section curve at the blade tip section according to the following logic:

[0148] (1) Both the maximum and minimum values ​​of the difference are positive: in this case, all points in the set of points of the curve of the surface of revolution at the blade tip section are outside the meridian flow path, and no correction is required;

[0149] (2) The maximum value of the difference is positive and the minimum value is negative: At this time, some points in the set of points of the curve of the surface of revolution at the blade tip profile section are outside the meridian flow path, while some points are inside the meridian flow path. The x-coordinates of all points in the set of points of the curve of the surface of revolution at the blade tip profile section are added to the absolute value of the minimum value of the difference;

[0150] (3) The maximum and minimum values ​​of the difference are both negative: At this time, all points of the blade root rotation surface section are within the meridian flow path, and the x-coordinates of all points in the rotation surface section curve point set at the blade tip blade section are added to the absolute value of the minimum value of the difference.

[0151] The calculation formula of the distance difference is the same as the calculation formula of the distance difference in the intersection detection and correction of the shape value point set of the blade basin and the blade back in the blade root or blade top section.

[0152] Specifically, if Figure 20 The distribution of the curve point set of the surface of revolution at the blade tip section of the guide vane of the single-stage axial compressor blade group and the curve point set of the casing is shown in the figure. In the first case ①, the curve point set of the surface of revolution at the blade tip section does not intersect with the curve point set of the casing in distribution, and all points are within the meridian flow path surrounded by the hub or casing surface. Correction is required. The minimum value of the difference is subtracted from the x-coordinates of all points in the curve point set of the surface of revolution at the blade tip section to obtain the corrected curve point set of the surface of revolution at the blade tip section. In the second case ①, the curve point set of the surface of revolution at the blade tip section does not intersect with the curve point set of the casing, and all points are within the meridian flow path surrounded by the hub or casing surface. In the first case ②, the rotation surface section curve point set at the blade top blade section and the casing curve point set have an intersection in distribution, and need to be corrected. The x-coordinates of all points in the rotation surface section curve point set at the blade top blade section are subtracted from the minimum value of the difference to obtain the corrected rotation surface section curve point set at the blade top blade section; In the third case ③, the rotation surface section curve point set at the blade top blade section and the casing curve point set do not intersect in distribution, and all the profile points are outside the meridian flow path surrounded by the hub or casing surface, so no correction is required. The rotation surface section curve point set at the blade top blade section of each blade in the single-stage axial compressor blade group is subjected to intersection detection and compared before and after correction. Figure 18 shown.

[0153] This operation is designed to detect the geometric distribution relationship between the rotation surface section curve point set at the blade top blade profile section and the casing curve point set, and to guide the correction of the blade top rotation surface section point set according to different situations. This step can accurately identify the error in the design of the rotation surface section curve point set at the blade top blade profile section by calculating the geometric difference between the points in the rotation surface section curve point set at the blade top blade profile section and the casing curve point set, and correct the rotation surface section curve point set at the blade top blade profile section when necessary. For example, when there is an error in the point distribution, the correction is achieved by adjusting the x-coordinates of all the shape value points to ensure that the rotation surface can be completely clipped by the casing surface and obtain the correct casing contour information. The operation classifies the relationship between the rotation surface section curve point set at the blade top blade profile section and the casing curve point set according to three different situations. By analyzing the extreme values ​​of the difference and the spatial distribution of the point set (such as intersection, inclusion within or outside the meridian flow path), the relative positional relationship between the receiver revolving surface cross-section curve point set and the receiver surface can be accurately identified, allowing targeted correction strategies to be implemented or determining whether correction is necessary. By precisely adjusting the maximum or minimum values ​​of the difference, it is possible to ensure that all points in the corrected receiver revolving surface cross-section curve point set maintain a consistent geometric relationship, avoiding overall shape deviations caused by local adjustments, thereby improving the geometric accuracy of flow path modeling.

[0154] S5: fitting the revolution surface section curve point sets at the three blade sections to obtain revolution surface section curves, performing a lofting operation between the revolution surface section curves to generate a revolution surface, and clipping the revolution surface using the hub or casing surface;

[0155] Specifically, if Figure 21 The process of generating a surface of revolution using lofting operations between the cross-sectional curves of the blade assembly of a single-stage axial compressor is shown in the following example. First, a spline curve is used to fit the cross-sectional curve points of the blade root, blade tip, and spanwise mid-section to generate the corresponding cross-sectional curves of the surface of revolution. A lofting operation is then performed between the three generated cross-sectional curves to generate the surface of revolution. At this point, the surface of revolution extends beyond the boundaries of the hub or casing, so it is necessary to trim the surface of revolution using the hub or casing surface to ensure that the surface of revolution matches the boundary of the flow channel.

[0156] This step is designed to generate a surface of revolution by fitting the surface of revolution cross-section curve point set. It also uses a lofting operation to ensure a smooth transition between different sections of the surface of revolution. It also uses the hub or casing surface to trim the surface of revolution to ensure that the surface of revolution matches the geometric boundaries of the flow channel, thereby providing an accurate geometric foundation for precise flow channel modeling, mesh generation, and subsequent fluid simulation. The surface of revolution cross-section curves generated by spline curve fitting in this step accurately reflect the shape characteristics of the blade at different cross-sections while ensuring smooth and continuous curves. Using a lofting operation to generate a surface of revolution between the surface of revolution cross-section curves at multiple blade sections not only ensures a smooth transition between different sections, generates a smooth surface of revolution shape, and maintains geometric continuity and flow channel smoothness, but also ensures that the surface of revolution fits the blade, ensuring that the flow channel generated by the sweeping operation can completely enclose the blade. The trimming operation ensures that the surface of revolution accurately matches the hub or casing surface boundary, avoiding exceeding the design area and restoring the surface of revolution to the actual flow channel design.

[0157] S6: For each blade, repeat the operations in S1-S6 to obtain the rotation surface of each blade;

[0158] Specifically, if Figure 22 The generation process of the rotating surfaces of the support plate ①, guide vane ②, rotor ③ and stator ④ in the blade group of a single-stage axial compressor, Figure 23 The process of clipping the hub and casing surfaces for the surfaces of revolution of the support plate (①), guide vanes (②), rotor (③), and stator (④) in a single-stage axial compressor blade assembly is shown below. Applying the same fitting, lofting, and clipping operations to each blade in the assembly generates its own surface of revolution. After following these same steps, each blade's surface of revolution aligns with the geometric boundaries of the hub and casing, forming a complete blade assembly surface of revolution.

[0159] This step is designed to ensure that the revolving surface of each blade is generated through the same geometric processing flow, to ensure the consistency and accuracy of the overall design of the revolving surface of the blade group, and to provide a high-quality geometric model for subsequent flow channel mesh generation and simulation analysis. This step performs the same operating steps on each blade to ensure that the revolving surface generation process of each blade is unified, and to ensure the geometric processing accuracy and consistency of each blade. By generating the revolving surface of each blade, it is possible to ensure that the overall geometric shape of the blade group matches the respective revolving surfaces. By repeating the same set of processes to automatically generate the revolving surface of each blade, the processing flow of the revolving surfaces of complex blade groups is simplified, the efficiency of modeling and optimization is improved, and it is convenient to use a function to implement it in programming.

[0160] S7: Calculate the outlet or inlet clipping lines between adjacent revolution surfaces, as well as the inlet clipping line of the first revolution surface and the outlet clipping line of the last revolution surface, and magnify the clipping lines by a certain multiple relative to their geometric centers. Use different sweep operations on the clipping lines according to the blade type to generate clipping surfaces. Traverse all revolution surfaces and use the corresponding clipping surfaces to clip the revolution surfaces to obtain clipped revolution surfaces. Create a meridian flow surface and clip it to obtain the inlet surface and outlet surface. This step includes the following substeps:

[0161] S71: traverse all leaves, average the last point of the root cross-sectional value point set of the previous leaf and the first point of the root cross-sectional value point set of the next leaf to obtain a root average point, average the last point of the tip cross-sectional value point set of the previous leaf and the first point of the tip cross-sectional value point set of the next leaf to obtain a tip average point, connect the root average point and the tip average point to obtain a clipping line between all leaves;

[0162] Specifically, if Figure 24 As shown in the clipping lines between blades in a single-stage axial compressor blade group, the profile point sets of the root and tip sections of each adjacent blade are processed. The last point of the preceding blade's root section profile point set is averaged with the first point of the following blade's root section profile point set to obtain the root average point. Similarly, for the tip section, the last point of the preceding blade's tip section profile point set is averaged with the first point of the following blade's tip section profile point set to obtain the tip average point. The root average point and the tip average point are then connected to generate the clipping lines between the blades.

[0163] This step is designed to ensure the geometric correctness of the cutting lines between adjacent blades in the blade group by averaging the shape value points of adjacent blades and generating smooth cutting lines, thereby providing a basis for the inlet and outlet cutting operations of the revolving surface. This step avoids the intersection of the cutting surface generated by the cutting line and the blade in subsequent steps by calculating the average points of the blade root and the blade tip and connecting them, and ensures that the revolving surface cut by the cutting surface contains the correct inlet and outlet information and can completely wrap the blade. Generating cutting lines between blades by taking the average value is relatively simple and efficient in programming. The calculation of the average value is an operation with linear time complexity, which can quickly process the shape value point set of adjacent blades and simplify the complex geometric processing logic. At the same time, since the generation of cutting lines relies on relatively simple mathematical operations, this process is easy to implement, debug and maintain, reducing the complexity of programming and improving the readability and execution efficiency of the code.

[0164] S72: For the first blade, calculate half of the difference in z values ​​between the first and last points of the root and tip cross-sectional profile point sets, determine the larger value, and subtract the larger value from the z value of the first point of the root and tip cross-sectional profile point sets to obtain the coordinates of two new clipping points. Connect the two clipping points to obtain the entrance clipping line of the first rotation surface.

[0165] Specifically, if Figure 24 As shown in the inlet cutting line of the first rotating surface of the blade group of a single-stage axial compressor, the coordinate difference between the first and last points of the blade root section and the blade tip section type value point set on the z-axis is first calculated, and half of it is taken as the reference value. Then, the blade root and blade tip sections are compared to see which section has the larger half of the z value difference, and the larger value is selected as the basis for positioning the subsequent cutting line. Next, the z value of the first point of the blade root and blade tip section type value point set is subtracted from the larger value to obtain two new cutting points. Finally, these two new cutting points are connected to generate the inlet cutting line of the first rotating surface.

[0166] This step is designed to obtain a reasonable geometric reference value for generating the entry clipping line of the first revolving surface. This step calculates the z-value difference between the blade root and tip sections and adjusts it using the larger value, providing a reasonable basis for locating the entry clipping line of the first revolving surface. This step uses the calculation of the z-value difference and the selection of the larger value, with clear logic and easy programming. This method can quickly determine the clipping point location and generate an entry clipping line that meets geometric requirements, simplifying the complex geometric processing process.

[0167] S73: Determine whether the entrance cutting line of the first rotating surface intersects with the entrance straight line segment formed by connecting the two first points in the hub and casing type value point set or is located outside the entrance straight line segment; if so, use the entrance straight line segment as the entrance cutting line of the first rotating surface;

[0168] Specifically, the inlet clipping line of the first revolving surface must be located within or coincide with the flow channel inlet; otherwise, the first revolving surface will obtain incorrect inlet information and lose geometric matching with the flow channel. Therefore, when the flow channel inlet is close to the leading edge of the blade and the generated inlet clipping line of the first revolving surface is located outside or intersects with the flow channel inlet, in order to ensure the rationality and continuity of the inlet of the first revolving surface and avoid unnecessary Boolean operations, the inlet straight line segment formed by connecting the two first points of the hub and casing point sets is directly used as the inlet clipping line of the first revolving surface.

[0169] This step is designed to ensure that the inlet trimming line of the first revolving surface matches the geometry of the runner inlet, thereby avoiding the generation of erroneous inlet information and ensuring the geometric continuity and rationality of the revolving surface and runner. This step ensures the precise matching of the revolving surface and runner geometry by keeping the inlet trimming line of the revolving surface consistent or overlapping with the runner inlet, avoiding erroneous information about the revolving surface inlet and maintaining overall geometric consistency. By directly using the inlet straight line segment connecting the hub and casing value points, complex Boolean operations and intersection checks are avoided, greatly simplifying the geometry processing process and improving computational efficiency.

[0170] S74: For the last blade, half of the difference in z value between the first and last points of the blade root and blade tip cross-sectional profile point sets is calculated, and the larger value is determined. The larger value is added to the z value of the last point of the blade root and blade tip cross-sectional profile point sets to obtain the coordinates of two new clipping points. The two clipping points are connected to obtain the exit clipping line of the last rotation surface.

[0171] Specifically, if Figure 24 As shown in the figure, the exit clipping line of the last rotating surface of the blade group of a single-stage axial flow compressor is first calculated. The coordinate difference between the first and last points of the blade root section and the blade tip section value point set on the z-axis is taken as the reference value. Then, the difference between the first and last points of the blade root section and the blade tip section is compared, and the larger value is selected as the basis for positioning the subsequent clipping line. Next, the larger value is subtracted from the z value of the first point of the blade root and blade tip section value point set to obtain two new clipping points. Finally, the two new clipping points are connected to generate the exit clipping line of the last rotating surface.

[0172] This step is designed to obtain a reasonable geometric reference value for generating the exit clipping line of the final revolving surface. This step calculates the z-value difference between the blade root and tip sections and adjusts it using the larger value, providing a reasonable basis for locating the exit clipping line of the final revolving surface. This step uses the calculation of the z-value difference and the selection of the larger value, with clear logic and easy programming. This method can quickly determine the clipping point location and generate an exit clipping line that meets geometric requirements, simplifying the complex geometric processing process.

[0173] S75: Determine whether the exit cutting line of the last rotating surface intersects with the exit straight segment formed by connecting the two tail points of the hub and casing type value point set or is located outside the exit straight segment; if so, use the exit straight segment as the exit cutting line of the last blade flow channel segment;

[0174] Specifically, the exit clipping line of the last revolving surface must be located within or coincide with the runner outlet. Otherwise, the last revolving surface will obtain incorrect exit information and lose geometric matching with the runner. Therefore, when the runner outlet is close to the blade trailing edge and the generated exit clipping line of the last revolving surface is located outside or intersects with the runner outlet, in order to ensure the rationality and continuity of the exit of the last revolving surface and avoid unnecessary Boolean operations, the exit straight line segment formed by connecting the two tail points of the hub and casing point set is directly used as the exit clipping line of the last revolving surface.

[0175] This step is designed to ensure that the geometry of the final revolving surface's exit trimming line matches the runner inlet, thus avoiding the generation of erroneous exit information and ensuring geometric continuity and rationality between the revolving surface and the runner. This step ensures precise geometry matching between the revolving surface and the runner by ensuring that the exit trimming line of the revolving surface is consistent or coincident with the runner outlet, avoiding errors in the revolving surface exit information and maintaining overall geometric consistency. By directly using the exit straight line segment connecting the hub and casing point, complex Boolean operations and intersection checks are avoided, greatly simplifying the geometry processing process and improving computational efficiency.

[0176] S76: Enlarge all cutting lines by a certain multiple according to their geometric center to ensure that the flow channel can be completely cut;

[0177] Specifically, for each cutting line, its geometric center can be directly obtained by averaging the cutting points of the blade top and blade root, which serves as the reference point for magnification. The magnification operation through this point can ensure that the extension of the cutting line in space is uniform. According to the calculated geometric center, the cutting line is proportionally enlarged by a certain multiple. By expanding the range of the cutting line, it can be ensured that the geometric area of ​​the flow channel boundary is not missed during cutting, and that the entire flow channel is completely and accurately cut, avoiding the problem of incomplete cutting. In the actual example, uniformly enlarging all cutting lines by 1.2 times according to the geometric center can ensure that the flow channel can be completely cut in subsequent operations.

[0178] This step is designed to enlarge all cutting lines by the geometric center to ensure that the range of the cutting lines is large enough to completely cover the flow channel geometry and avoid the situation where the geometric area is not completely cut during the cutting process. This step of enlarging the cutting lines by the geometric center can ensure that the geometric shape of the cutting lines remains consistent during enlargement, avoid geometric deviations caused by uneven enlargement, ensure the accuracy of the cutting process, and the position after enlargement does not shift relative to the position before enlargement, avoid the enlarged cutting lines from intersecting with the blades, and avoid errors in the inlet and outlet information of the rotating surface. By enlarging the cutting lines at one time, it is ensured that subsequent cutting operations can be carried out smoothly, reducing complex multiple corrections or adjustments, simplifying the entire cutting process, and improving processing efficiency.

[0179] S77: When the blade type is a turbomachinery, traverse all the clipping lines and use a rotation sweep operation on them to sweep 360 degrees to generate a closed clipping surface; when the blade type is a planar cascade, traverse all the clipping lines and use a translation sweep operation on them to translate and sweep a certain distance to generate a clipping plane;

[0180] Specifically, if Figure 25 As shown in the figure, all the trimming surfaces of the single-stage axial compressor blade group are shown. Since the blade type in this example is impeller machinery, all the trimming lines are swept 360 degrees using the rotation sweep operation to generate a set of closed trimming surfaces.

[0181] This step is designed to generate appropriate clipping geometry through different sweeping operations according to the type of blade, so as to accurately define the inlet and outlet boundaries of the sub-channel segment. This operation distinguishes between impeller machinery and plane blades, and uses rotational sweep and translational sweep operations respectively to ensure that the clipping geometry matches the blade type. For the three-dimensional surface clipping of impeller machinery, rotational sweeping generates closed surfaces that are more in line with its complex shape, while translational sweeping is suitable for two-dimensional clipping of plane blades, ensuring that the clipping process is reasonable and efficient. The clipping method is automatically selected according to the blade type to avoid the complexity of manually adjusting the clipping geometry. This improves the degree of automation of the processing flow and reduces the workload of programming and geometry processing.

[0182] S78: For each of the revolution surfaces, use its corresponding inlet clipping surface and outlet clipping surface to perform clipping to obtain a clipped revolution surface;

[0183] Specifically, if Figure 26The inlet and outlet trimming process for the rotating surfaces of the support plate ①, guide vanes ②, rotor ③, and stator ④ in a single-stage axial compressor blade assembly is shown. Each blade's rotating surface is trimmed using its corresponding inlet and outlet trimming surfaces to obtain correct inlet and outlet information. Because the rotating surfaces of adjacent blades are trimmed using the same trimming surface, the inlets and outlets of adjacent rotating surfaces are precisely matched in the circumferential direction. This provides a highly accurate geometric foundation for the subsequent generation of dynamic and static interference surfaces between adjacent blades.

[0184] This step is designed to trim the rotating surface of each blade using the corresponding inlet and outlet trimming surfaces to ensure that the rotating surface of each blade has the correct inlet and outlet geometric information. By using precise trimming surfaces to trim the rotating surface of each blade, the geometric information of the rotating surface at the inlet and outlet is guaranteed to be accurate, ensuring the integrity and correctness of the flow channel, and providing a reliable geometric basis for subsequent simulation and analysis. The rotating surfaces of adjacent blades are trimmed by the same trimming surface, ensuring that the outlet and inlet of adjacent rotating surfaces are accurately matched in the circumferential direction, avoiding geometric discontinuity and misalignment problems, and providing a high-precision foundation, which is convenient for reducing geometric errors when generating dynamic and static interference surfaces or interfaces in the subsequent generation, and improving the accuracy of interpolation of dynamic and static interference surfaces or interfaces during numerical simulation calculations.

[0185] S79: When the inlet cutting line of the first rotating surface is located inside the inlet straight line segment, or the outlet cutting line of the last rotating surface is located inside the outlet straight line segment, the hub and casing contour curve are connected with the inlet straight line segment and the outlet straight line segment at the same endpoints to form a closed loop and create a meridian flow surface, the inlet cutting surface of the first rotating surface is used to cut the meridian flow surface to obtain the flow channel inlet surface, and the outlet cutting surface of the last rotating surface is used to cut the meridian flow surface to obtain the flow channel outlet surface.

[0186] Specifically, if Figure 27 The process of obtaining the flow channel inlet and outlet surfaces of a single-stage axial compressor blade group is shown in this example. In this example, the inlet clipping line of the first revolution surface is located within the inlet straight line segment, and the outlet clipping line of the last revolution surface is located within the outlet straight line segment. Therefore, the inlet and outlet straight line segments are first obtained by connecting the first and last points of the hub and casing type value point sets, respectively. Then, a meridian flow surface is generated within the closed quadrilateral formed by the inlet and outlet straight line segments, the hub curve, and the casing curve. The inlet clipping surface of the first revolution surface is used to clip the meridian flow surface to obtain the flow channel inlet surface, and the outlet clipping surface of the last revolution surface is used to clip the meridian flow surface to obtain the flow channel outlet surface.

[0187] This step is designed to generate and trim closed meridional flow surfaces to obtain additional flow channel inlet and outlet surfaces. This avoids the problem of excessive meshing of the first and last sub-flow channel segments when generating meshes due to the excessive length of the inlet and outlet portions of the first and last revolving surfaces, thereby improving computational efficiency while ensuring accuracy. When the flow channel inlet and outlet portions are long but there are no blades interfering with the flow, the flow in these sections is relatively simple, and therefore excessive meshing is not required to improve computational accuracy. If the flow channel inlet surface is merged with the first and last revolving surfaces, and the flow channel outlet surface is merged with the last revolving surface, the presence of the boundary layer or the tip-root clearance will lead to an increase in the overall mesh size and ineffective meshing, but the computational accuracy and precision will not be improved. Therefore, by generating additional flow channel inlet and outlet surfaces, while ensuring the geometric matching accuracy of the interfaces, limiting the length of the first and last revolving surfaces, this can effectively reduce the meshing of the first and last sub-flow channel segments, avoiding the excessive meshing caused by the long inlet and outlet sections, and thus optimizing the mesh distribution.

[0188] S8: Traverse all the cropped revolution surfaces and, based on the blade type, use a sweep operation to sweep the corresponding single-cycle or multi-cycle angle or distance for each revolution surface to generate a sub-flow channel segment. This step includes the following sub-steps:

[0189] S81: Sweeping each of the cropped revolving surfaces according to their respective rotation angles α or translation distances d to obtain a single-periodic sub-flow channel segment;

[0190] In the impeller machinery, the sweep angle of the single-cycle sub-channel segment is calculated based on the number of blades in the blade row, and the formula is:

[0191]

[0192] Where α is the sweep angle of the sub-channel segment in a single period, and Periodicity is the number of blades in the impeller row in the impeller machine;

[0193] In a planar cascade, the distance swept by a single-period sub-channel segment is the translation distance d;

[0194] Specifically, if Figure 28 The generation process of single-periodic sub-flow path segments for intermediate compressor blades ①, planar cascades ②, and single-stage axial compressor blade groups ③ is shown. For the single-stage axial compressor blade group and compressor blades of the turbomachinery blade type, their rotational surfaces are swept by their respective rotation angles α to obtain the single-periodic sub-flow path segments of each blade. For the planar cascade example, the rotational surface of this example is swept by its translation distance d to obtain the single-periodic sub-flow path segments of the planar cascade.

[0195] This step is designed to generate single-periodic sub-flow channel segments through rotational or translational sweeping operations, thereby ensuring that the single-periodic sub-flow channel segments have precise geometric shapes under the conditions of precise matching of periodic conditions and interfaces, and provide a reliable geometric basis for subsequent mesh generation and fluid simulation. This step flexibly handles two different types of blades, impeller machinery and planar blades, and generates sub-flow channel segments that meet their respective needs through different sweeping methods (rotation or translation), adapting to the characteristics of different blade structures. By automatically calculating the rotation angle α according to the number of blades or using the translation distance d, the steps of complex geometric processing are simplified, the modeling efficiency is improved, the complexity of manual adjustment is reduced, and it can ensure that all sub-flow channel segments have the correct periodicity. Whether it is rotational sweeping or translational sweeping, it can ensure that the generated single-periodic sub-flow channel segments meet the geometric design requirements, avoid flow channel inconsistencies caused by geometric misalignment or inaccurate sweeping, and ensure high-quality geometric modeling.

[0196] S82: For a multi-periodic sub-channel segment, set a sweep cycle repetition number R of the sub-channel segment, and sweep each of the cropped revolving surfaces according to their respective rotation angles α′ or translation distances D to obtain a multi-periodic sub-channel segment.

[0197] At this time, the rotation sweep angle of the rotating surface in the impeller machine is:

[0198] α′=α·R;

[0199] Where α′ is the rotation sweep angle of the multi-periodic sub-channel segment, α is the sweep angle of the single-periodic sub-channel segment, and R is the number of repetitions of the sweep cycle of the sub-channel segment;

[0200] At this time, the translation sweep distance of the rotating surface in the plane cascade is:

[0201] D = d·R;

[0202] Where D is the translational sweep distance of the multi-periodic sub-channel segment, α is the translational sweep distance of the single-periodic sub-channel segment, and R is the number of repetitions of the sweep cycle of the sub-channel segment;

[0203] Specifically, if Figure 29 The multi-periodic sub-flow path segment generation process for intermediate compressor blades ①, planar cascades ②, and single-stage axial compressor blade groups ③ is shown. For the single-stage axial compressor blade group and compressor blades of the turbomachinery blade type, their rotating surfaces are rotated and swept according to their respective rotation angles α′ to obtain the multi-periodic sub-flow path segments of each blade. For the planar cascade example, the rotating surface of this example is translated and swept according to its translation distance D to obtain the multi-periodic sub-flow path segments of the planar cascade.

[0204] This step is designed to generate multi-periodic sub-channel segments through rotational or translational sweeping operations, thereby ensuring that the multi-periodic sub-channel segments have precise geometric shapes under the conditions of precise matching of periodic conditions and interfaces, and provide a reliable geometric basis for subsequent mesh generation and fluid simulation. This step flexibly handles two different types of blades, impeller machinery and planar blades, and generates sub-channel segments that meet their respective needs through different sweeping methods (rotation or translation), adapting to the characteristics of different blade structures. By automatically calculating the rotation angle α′ according to the number of cycles or using the translation distance D, the steps of complex geometric processing are simplified, the modeling efficiency is improved, the complexity of manual adjustment is reduced, and it can ensure that all sub-channel segments have the correct periodicity. Whether it is rotational sweeping or translational sweeping, it can ensure that the generated multi-periodic sub-channel segments meet the geometric design requirements, avoid flow channel inconsistencies caused by geometric misalignment or inaccurate sweeping, and ensure high-quality geometric modeling.

[0205] S83: Sweeping the flow channel inlet surface by the same sweep angle or translation distance as the first rotation surface to generate a flow channel inlet segment, and sweeping the flow channel outlet surface by the same sweep angle or translation distance as the last rotation surface to generate a flow channel outlet segment.

[0206] Specifically, if Figure 30 The process of generating the inlet and outlet sections of a single-stage axial compressor blade group is shown in Figure 2. The geometry of the inlet section is obtained by sweeping the inlet surface at the same angle as the first turning surface. The outlet surface of the inlet section precisely matches the inlet surface of the first sub-section at the interface. The geometry of the outlet section is obtained by sweeping the outlet surface at the same angle as the last turning surface. The inlet of the outlet section precisely matches the outlet of the last sub-section at the interface. The inlet and outlet sections of the outlet section, as well as all the sub-sections generated by the blades, cover the entire flow area in the duct.

[0207] This step is designed to define the complete fluid flow region by generating the inlet and outlet sections and ensuring their precise alignment with the first and last sub-sections at their interfaces. This ensures geometric continuity and accuracy throughout the duct, providing a high-quality geometric foundation for subsequent mesh generation and flow simulation. This step precisely matches the inlet and outlet sections with their corresponding sub-sections, avoiding geometric discontinuities or misalignments and improving modeling integrity. This precise geometric alignment provides a reliable foundation for subsequent mesh generation and CFD simulation, ensuring that errors caused by geometric discontinuities are eliminated during the calculation process and improving the accuracy of the simulation results. By performing a unified sweep operation on the inlet, outlet, and sub-sections, the geometry generation process is simplified, reducing the complexity of manual adjustments and improving modeling efficiency. By modeling the inlet and outlet sections separately, the length of the inlet portion of the first sub-section and the outlet portion of the last sub-section are limited. Since there are no blades interfering with the inlet and outlet sections, the flow characteristics are relatively simple, requiring only moderate mesh refinement at the walls. Furthermore, when generating multi-periodic fluid channels, the inlet and outlet segments only need to be swept through one period. This step avoids the inlet and first sub-channel segments, and the outlet and last sub-channel segments, from being overly large or overly dense due to the presence of blades when modeling multiple periods in a continuous manner. This reduces computational efficiency.

[0208] S9: For each blade, a lofting operation is performed between the blade cross-section sets to generate a three-dimensional blade. Based on the number of periods of the sub-flow channel segments, a Boolean operation is performed between each sub-flow channel segment and its corresponding three-dimensional blade, and the corresponding three-dimensional blade is subtracted from the sub-flow channel segment to generate multiple single-periodic or multi-periodic fluid channels. This step includes the following sub-steps:

[0209] S91: Traverse the blade profile cross-section set of each blade, fit the blade back and blade basin shape value point set to obtain the blade back and blade basin curves, connect the blade basin curve and blade back curve of each blade profile cross-section at the leading edge and trailing edge endpoints to form a closed blade profile cross-section ring, and use the lofting operation between the blade profile cross-section rings to generate a three-dimensional blade;

[0210] Specifically, if Figure 31 The three-dimensional blade generation process for the intermediate compressor blade ①, the planar cascade ②, and the single-stage axial compressor blade group ③ is shown as follows. For each blade profile cross-section set, a spline curve is used to fit the shape value point set of the blade back and blade basin of each blade profile cross-section to obtain the blade back and blade basin curves. The blade basin curve and the blade back curve are then connected at the leading and trailing edge endpoints to form a closed blade profile ring. Finally, the three-dimensional blade is generated using the lofting operation in sequence between the blade profile cross-section rings.

[0211] This step is to fit the blade back and blade basin curves through spline curves, and connect them at the leading edge and trailing edge to form a closed blade section ring, and finally generate the geometric shape of the three-dimensional blade through lofting operations, so as to ensure that the geometric modeling accuracy and smoothness of the blade meet the design requirements of numerical simulation. This step uses spline curves to fit the type value point set of the blade back and blade basin, so that the generated blade section curve is smoother, the sharp changes in geometry are reduced, and the geometric modeling accuracy of the blade is improved. Through the automated operations of fitting, connecting and lofting, the modeling process of complex blades is greatly simplified, the time and error of manual modeling are reduced, and the design efficiency is improved. This method is not only applicable to the blade design of axial compressors, but also to the design of other types of blades (such as plane blade grids), and has strong versatility and flexibility.

[0212] S92: For the single-periodic sub-channel segments, perform a Boolean subtraction operation on each single-periodic sub-channel segment generated by a blade and its corresponding three-dimensional blade, subtracting the three-dimensional blade from the single-periodic sub-channel segment to generate a single-periodic fluid channel;

[0213] Specifically, if Figure 32 The generation process of single-periodic sub-flow channel segments for intermediate compressor blades ①, planar cascades ②, and single-stage axial compressor blade groups ③ is shown in the figure. A Boolean operation is performed on each single-periodic sub-flow channel segment and its corresponding three-dimensional blade. The three-dimensional blade is subtracted from the single-periodic sub-flow channel segment to generate a single-periodic fluid channel.

[0214] This step is to perform geometric subtraction between each single-cycle sub-channel segment and the corresponding three-dimensional blade through Boolean operations to generate a single-cycle fluid channel that does not contain blades, thereby accurately defining the flow path of the fluid between the blades and providing an accurate geometric model for subsequent computational fluid dynamics simulation and analysis. This step subtracts the three-dimensional blades from the sub-channel segment, and the generated fluid channel accurately reflects the actual flow area of ​​the fluid in the blade group, ensuring that the fluid channel geometry meets the design requirements. By subtracting the three-dimensional blades, the geometric shape of the flow channel automatically adapts to the geometric characteristics of the blades, avoiding the geometric mismatch between the fluid channel and the blades, and ensuring the continuity of the fluid flow. The accurately generated fluid channel helps to further analyze the flow characteristics of the fluid between the blades, optimize the blade design and fluid dynamics performance, and improve the overall performance of the compressor or blade group.

[0215] S93: For the multi-periodic sub-channel segment, when the blade type is an impeller machine, each three-dimensional blade is rotated R-1 times around the rotation axis, with the angle of each rotation being the angle α swept by the single-periodic sub-channel segment, and the three-dimensional blade before and after each rotation is subtracted from each multi-periodic sub-channel segment generated by the blade to generate a multi-periodic fluid channel;

[0216] Specifically, if Figure 33As shown in the process of generating multi-periodic sub-channel segments of blade group ③ of a single-stage axial compressor, the period number of the support plate sub-channel segment is set to one, and the period number of the other blade sub-channel segments is set to three. Therefore, a Boolean operation is performed on the single-periodic support plate sub-channel segment and the support plate, and the support plate is subtracted from the single-periodic support plate sub-channel segment to generate a single-periodic support plate fluid channel; the other blades except the support plate are rotated twice around the axis, and the angle of each rotation is the angle α of the rotation sweep of the blade's respective single-periodic sub-channel segment. Finally, a Boolean operation is performed on each three-periodic sub-channel segment and its corresponding three-dimensional blade, and the three-periodic sub-channel segment is subtracted from the three-periodic blade before and after each rotation to generate the corresponding three-periodic fluid channel. Figure 32 Figure 2 shows the generation process of a three-periodic sub-channel segment for intermediate compressor blade ②. The compressor sub-channel segment has a period of three. Therefore, the compressor blade is rotated twice around its axis, with each rotation angle being the angle α swept by the single-periodic sub-channel segment. Finally, a Boolean operation is performed on the three-periodic sub-channel segment and the three-dimensional blade. The three-periodic fluid channel is generated by subtracting the three-dimensional blade before and after each rotation from the three-periodic sub-channel segment.

[0217] This step is designed to generate multi-periodic fluid channels through Boolean operations and rotational sweeps, ensuring that the geometry of the fluid channels matches the periodic arrangement of the blades, thereby accurately defining the fluid flow area of ​​the blade group under multi-periodic conditions, and providing an accurate geometric basis for subsequent mesh generation and fluid dynamics simulation. This step generates a multi-periodic blade arrangement by rotating the blades, ensuring that all blades are geometrically matched under multi-periodic conditions, and avoiding flow instability or errors caused by geometric mismatch. The multi-periodic fluid channel generated by subtracting the corresponding three-dimensional blades from the multi-periodic sub-channel segment through Boolean operations accurately reflects the actual fluid flow area, ensuring the geometric accuracy and reliability of the fluid simulation results. According to the design requirements, the different number of periods of the blades can be flexibly set to ensure that the flow channel is consistent with the periodicity of the blades and meet the geometric requirements of the complex blade group.

[0218] S94: For the multi-periodic sub-channel segment, when the blade type is a planar cascade, each three-dimensional blade is translated R-1 times in the blade arrangement direction, and the distance of each translation is the distance swept by the single-periodic sub-channel segment, which is the translation distance d. The multi-periodic sub-channel segment generated by the blade is subtracted from the three-dimensional blade before and after each translation to generate a multi-periodic fluid channel.

[0219] Specifically, if Figure 33The generation process of a multi-periodic sub-channel segment of the mid-plane cascade ① is shown in FIG. The number of periods of the plane cascade sub-channel segment is set to three. Therefore, the plane cascade blades are translated twice in the direction of blade arrangement. The distance of each translation is the distance d swept by the translation of the single-periodic sub-channel segment of the plane cascade. Finally, a Boolean operation is performed on the three-periodic sub-channel segment and the three-dimensional blade. The three-periodic blade before and after each translation is subtracted from the three-periodic sub-channel segment to generate a three-periodic fluid channel.

[0220] This step is designed to generate multi-periodic fluid channels through Boolean operations and translation sweeps, ensuring that the geometry of the fluid channels matches the periodic arrangement of the blades, thereby accurately defining the fluid flow region of the blade group under multi-periodic conditions and providing a precise geometric foundation for subsequent mesh generation and fluid dynamics simulation. This step generates a multi-periodic blade arrangement by translating the blades, ensuring that all blades are geometrically matched under multi-periodic conditions, avoiding flow instabilities or errors caused by geometric mismatch. Other effects achieved in this step are the same as the generation process of multi-periodic fluid channels in turbomachinery.

[0221] The method of the present invention is based on the framework of high-precision aerodynamic simulation of aircraft engine blades, combined with the basic knowledge of impeller machinery and plane blade cascades, to accurately construct a multi-blade row and multi-cycle flow channel model. The method emphasizes adjusting the blade root or blade tip cross section by using intersection detection and correction strategies, so that the blade tip and blade root clearance characteristics can be correctly retained or corrected, ensuring that the Boolean operation of the three-dimensional blade and the flow channel can be performed correctly. Discrete the blade root, blade tip and blade back and blade basin curves in the middle of the span, and calculate the average value of the discrete point set to obtain the approximate mid-arc point set. Insert points at the beginning and end of the approximate mid-arc point set and smooth it to obtain the rotation surface section curve point set, so that the approximate mid-arc line extends smoothly toward the inlet and inlet directions. Apply intersection detection and correction to slightly adjust the rotation surface section curve point set at the blade root and blade tip blade section, and use lofting operation to generate the rotation surface to ensure that the rotation surface can be completely clipped by the hub and casing surfaces, and obtain the correct boundary information of the hub and casing wall. An automated algorithm is used to accurately calculate the cutting surfaces between the blades and further cut the revolving surfaces, so that the swept sub-flow channel segments have very high matching accuracy at the interface. The method of obtaining sub-flow channel segments by sweeping the revolving surfaces in a single cycle or multiple cycles not only ensures the accuracy of the periodic surfaces of the sub-flow channel segments, but also makes the inlet surface, outlet surface, hub surface and casing surface smooth and continuous, avoiding common and difficult-to-handle geometric errors such as repeated edges, repeated surfaces or small protrusions, thereby improving the accuracy and stability of mesh generation and numerical simulation. By performing lofting operations between the blade section rings, three-dimensional blades are generated quickly and accurately, and Boolean operations are performed between the three-dimensional blades and the sub-flow channel segments to obtain the final fluid channel model, achieving accurate modeling of the actual fluid flow area between blades in industrial-grade engine ducts.

[0222] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the application embrace any and all variations of the present application that fall within the scope of the general inventive concept as defined by the appended claims and their equivalents. The specification and examples are to be regarded as exemplary in nature and not as restrictive in any way.

[0223] It should be understood that the application is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application is to be defined by the appended claims rather than by the description preceding them.

Claims

1. A high-precision modeling method for multi-row and multi-cycle blade mechanical flow channels, characterized in that: include: S1: Fit the hub and casing type value point sets to obtain the hub and casing curves, and use the sweep operation to generate the hub or casing surface according to the blade type; S2: Detect whether the blade root or blade tip section in the blade profile section set intersects with the hub or casing surface, and adjust the profile point sets of the blade back and blade basin of the blade root or blade tip section in the blade profile section set according to the intersection situation, and fit the profile point sets of the blade back and blade basin of the blade profile sections at the blade root, the middle of the blade span, and the blade tip to obtain the blade back and blade basin curves at the three blade profile sections; S3: scattering the blade back and blade basin curves at the three blade profile sections into blade back and blade basin curve point sets at equal distances, averaging the points at corresponding positions in the blade back and blade basin point sets to obtain an approximate mid-arc point set, inserting points at the beginning and end of the approximate mid-arc point set and aligning the beginning and end points to obtain a revolving surface section curve point set, applying a smoothing algorithm to adjust the coordinates of the points in the revolving surface section curve point set to complete a smooth extension of the approximate mid-arc line toward the exit and entrance directions; S4: Detecting whether the revolution surface cross-section curve point set at the blade root or blade tip airfoil section intersects with the hub or casing curved surface, and adjusting the coordinates of the revolution surface cross-section curve point set at the blade root or blade tip airfoil section according to the intersection situation; S5: fitting the revolution surface section curve point sets at the three blade sections to obtain revolution surface section curves, performing a lofting operation between the revolution surface section curves to generate a revolution surface, and clipping the revolution surface using the hub or casing surface; S6: For each blade, repeat the operations in S1-S6 to obtain the rotation surface of each blade; S7: Calculate the outlet or inlet clipping lines between adjacent revolution surfaces, as well as the inlet clipping line of the first revolution surface and the outlet clipping line of the last revolution surface. Magnify the clipping lines by a certain multiple relative to their geometric centers. Use different sweep operations on the clipping lines according to the blade type to generate clipping surfaces. Traverse all revolution surfaces and use the corresponding clipping surfaces to clip the revolution surfaces to obtain the clipped revolution surfaces. Create a meridian flow surface and clip it to obtain the flow channel inlet surface and flow channel outlet surface. S8: traverse all the trimmed revolution surfaces, and according to the blade type, use a sweep operation to sweep the corresponding single-cycle or multi-cycle angle or distance for each revolution surface to generate a sub-flow channel segment; S9: For each blade, a lofting operation is used between the blade section sets to generate a three-dimensional blade. According to the number of periods of the sub-channel segments, a Boolean operation is performed between each of the sub-channel segments and its corresponding three-dimensional blade. The corresponding three-dimensional blade is subtracted from the sub-channel segment to generate multiple single-period or multi-period fluid channels.

2. A high-precision modeling method for multi-row and multi-cycle blade mechanical flow channels according to claim 1, characterized in that: S1 includes the following sub-steps: S11: Use spline curves to fit the hub and casing type value point sets respectively to obtain hub and casing curves; S12: When the blade type is a rotary machine, the hub and casing curves are rotated and swept 180 degrees to obtain a hub or casing curved surface of the rotary machine; S13: When the blade type is a planar cascade, the hub and casing curves are simultaneously translated and swept by a certain distance in the positive direction and the negative direction of the blade arrangement direction in the cascade in a Cartesian coordinate system to obtain a hub or casing curved surface of the planar cascade.

3. The multi-row, multi-cycle, high-precision modeling method for blade mechanical flow channels according to claim 1, characterized in that: S2 includes the following sub-steps: S21: uniformly define the casing as the blade tip and the hub as the blade root, and scatter the hub and casing curves into a sufficient number of points at equal distances to obtain a hub curve point set and a casing curve point set; S22: Traverse the shape value point set of the blade root section, blade back and blade basin, and calculate the value of each shape value point in the Cartesian coordinate system. z The difference between the distance of the axis and the radial height of the point closest to the current value point in the hub curve point concentration, and find the maximum and minimum values ​​of the difference during the traversal process; S23: Adjust the shape value point set of the blade root section blade basin and blade back according to the following logic: (1) The maximum and minimum values ​​of the difference are both positive: At this time, all the shape value points of the blade basin and blade back of the blade root section are within the meridian flow path surrounded by the hub or casing surface. Further judgment is made as to whether the minimum value of the difference is greater than the user-defined blade root clearance value. If so, it indicates that there is a blade root clearance and the radial height of the blade root section is not adjusted. If it is less than the user-defined blade root clearance value, it indicates that there is an error in the blade design and needs to be corrected. x The maximum value of the coordinate minus the difference; (2) The maximum value of the difference is positive and the minimum value is negative: At this time, some of the shape value points of the blade root section blade basin or blade back are outside the meridian flow path surrounded by the hub or casing surface, and some are inside the meridian flow path, indicating that there is an error in the blade design and it needs to be corrected. x The maximum value of the coordinate minus the difference; (3) The maximum and minimum values ​​of the difference are both negative: At this time, all the shape value points of the blade root section, blade back and blade basin are outside the meridian flow path surrounded by the hub or casing surface, indicating that the blade design is correct and no correction is required; (4) If the minimum difference between the blade root section and the casing is positive and greater than the user-defined blade root clearance value, it indicates that there is an uncorrectable error in the blade design, and the subsequent process is terminated; S24: Traverse the shape value point set of the blade top section, blade basin and blade back, and calculate the value of each shape value point in the Cartesian coordinate system. z The difference between the distance of the axis and the radial height of the point closest to the current value point in the casing curve point concentration, and find the maximum and minimum values ​​of the difference during the traversal process; S25: Adjust the shape value point set of the blade top section, blade basin and blade back according to the following logic: (1) The maximum and minimum values ​​of the difference are both positive: At this time, all the shape value points of the blade tip section, blade back and blade basin are outside the meridian flow path surrounded by the hub or casing surface, indicating that the blade design is correct and no correction is required; (2) The maximum value of the difference is positive and the minimum value is negative: At this time, some of the shape value points of the blade basin or blade back of the blade tip section are outside the meridian flow path surrounded by the hub or casing surface, and some are inside the meridian flow path, indicating that there is an error in the design of the blade and it needs to be corrected. x The absolute value of the minimum of the coordinates plus the difference; (3) The maximum and minimum values ​​of the difference are both negative: At this time, all the shape value points of the blade basin and the blade back of the blade tip section are within the meridian flow path surrounded by the hub or casing surface. Further judge whether the absolute value of the maximum value of the difference is greater than the user-defined blade tip clearance value. If so, it indicates that there is a blade tip clearance and the radial height of the blade root section is not adjusted; if it is less than the user-defined blade tip clearance value, it indicates that there is an error in the blade design and it needs to be corrected. All the shape value points of the blade root section are adjusted. x The absolute value of the minimum of the coordinates plus the difference; (4) If the maximum difference between the tip section and the casing is negative and its absolute value is greater than the user-defined tip clearance value, it means that there is an uncorrectable error in the blade design, and the subsequent process is terminated; In the impeller machinery, the calculation formula for the distance difference is: ； In a planar cascade, the distance difference is calculated as: ； in, is the coordinate of the value point of the blade root or blade top section, blade back or blade basin in the Cartesian coordinate system, where The coordinates represent the radial height, The radial height of the hub or casing value point closest to the current value point; S26: Fitting the blade back and blade basin profile point sets of the blade profile sections at the blade root, the middle of the blade span, and the blade tip in the blade profile section concentration to obtain blade back and blade basin curves at the three blade profile sections.

4. The multi-row, multi-cycle, high-precision modeling method for blade mechanical flow channels according to claim 1, characterized in that: S3 includes the following sub-steps: S31: scattering the blade back and blade basin curves at the three blade sections into blade back and blade basin curve point sets at equal distances. The number of discrete points on the blade back and blade basin must be the same and can be customized by the user. S32: averaging the corresponding points in the leaf basin and leaf back curve point sets in order from the entrance to the exit, and saving them in order to the approximate mid-arc point set; S33: Calculate the approximate arc point set from the first point to the last point z The difference on the axis, i.e. the chord length, is recorded as b , as the basic unit of extended length; S34: Insert a series of new points at the beginning of the approximate arc point set. The insertion formula is as follows: ； And insert a series of new points far from the tail of the mid-arc point set. The insertion formula is as follows: ； Obtain the final set of revolution surface section curve points; in is a series of new points inserted at the head of the approximate mid-arc point set, is a series of new points inserted at the end of the approximate mid-arc point set; , n is the number of insertion points; is the coordinate of the first point in the mid-arc point set sequence, is the coordinate of the last point in the mid-arc point set sequence; The smallest value in the hub and casing coordinates z Value, when Less than When the last point of the head insertion is outside the flow channel, it is automatically adjusted to the coordinates of the meridian flow path entrance. z value; The largest value in the hub and casing coordinates z Value, when Greater than When the last point of the tail insertion is outside the flow channel, it is automatically adjusted to the coordinates of the meridian flow path outlet. z value; 、 、 、 、 、 are coordinate adjustment coefficients, where 、 It is used to determine the position of the first point of the head insertion according to the first point of the approximate mid-arc point set. It is used to determine the position of the last point inserted at the head according to the position of the first point inserted at the head of the approximate arc point set. 、 It is used to determine the position of the first point of the tail insertion according to the tail point of the approximate mid-arc point set. It is used to determine the position of the first point inserted at the tail of the approximate mid-arc point set and the position of the last point inserted at the tail; these coordinate adjustment coefficients jointly determine the overall shape and length of the revolving surface and the sub-flow channel segment; S35: Traverse all the points of the cross-section curve of the revolution surface and find the largest z value and the smallest z value ; Set the first point in each revolution surface section curve point set z The value is , the last point z The value is ; S36: traverse all the points of the cross-section curve of the revolution surface, and adjust the coordinates of the cross-section curve point set of the revolution surface by applying the smoothing algorithm for multiple iterations; for each iteration, the new smoothing point The coordinate calculation formula is: ； in is the smoothed point, is the first point before smoothing, is the last point before smoothing, 、 This means keeping the first and last points unchanged. .

5. The multi-row, multi-cycle, high-precision modeling method for blade mechanical flow passages according to claim 3 is characterized in that: S4 includes the following sub-steps: S41: traverse the rotation surface section curve point set at the blade root blade section, and calculate the distance from each point to the z The difference between the distance of the axis and the radial height of the point closest to the current point in the hub curve point set, and finding the maximum and minimum values ​​of the difference in the iterative process; S42: Adjust the point set of the revolution surface section curve at the blade root profile section according to the following logic: (1) The maximum and minimum values ​​of the difference are both positive: At this time, all points in the set of the curve points of the rotating surface section at the blade root profile section are within the meridian flow path. x The maximum value of the coordinate minus the difference; (2) The maximum value of the difference is positive and the minimum value is negative: At this time, some points in the curve point set of the rotating surface section at the blade root blade section are outside the meridian flow path, and some points are inside the meridian flow path. x The maximum value of the coordinate minus the difference; (3) The maximum and minimum values ​​of the difference are both negative: At this time, all points of the blade root rotation surface section are outside the meridian flow path, and no correction is required; The calculation formula of the distance difference is the same as that of the distance difference in the intersection detection and correction of the shape value point set of the blade base and the blade back at the blade root or blade tip section. S43: traverse the rotation surface section curve point set at the blade top blade section, and calculate the distance from each point to the z The difference between the distance of the axis and the radial height of the point closest to the current point in the casing curve point set, and finding the maximum and minimum values ​​of the difference in the iterative process; S44: Adjust the point set of the revolution surface section curve at the blade tip section according to the following logic: (1) The maximum and minimum values ​​of the difference are both positive: at this time, all points in the set of points of the curve of the rotating surface section at the blade tip section are outside the meridian flow path, and no correction is required; (2) The maximum value of the difference is positive and the minimum value is negative: At this time, some points in the curve point set of the revolving surface section at the blade tip section are outside the meridian flow path, and some points are inside the meridian flow path. x The absolute value of the minimum of the coordinates plus the difference; (3) The maximum and minimum values ​​of the difference are both negative: At this time, all the profile points of the blade root revolving surface section are within the meridian flow path, and the revolving surface section curve points at the blade tip blade section are concentrated to all the points. x The absolute value of the minimum of the coordinates plus the difference; The calculation formula of the distance difference is the same as the calculation formula of the distance difference in the intersection detection and correction of the shape value point set of the blade basin and the blade back in the blade root or blade top section.

6. The multi-row, multi-cycle, high-precision modeling method for blade mechanical flow channels according to claim 1, characterized in that: S7 includes the following sub-steps: S71: traverse all leaves, average the last point of the root cross-sectional value point set of the previous leaf and the first point of the root cross-sectional value point set of the next leaf to obtain a root average point, average the last point of the tip cross-sectional value point set of the previous leaf and the first point of the tip cross-sectional value point set of the next leaf to obtain a tip average point, connect the root average point and the tip average point to obtain a clipping line between all leaves; S72: For the first blade, calculate the value between the first and last points of the blade root and blade tip cross-sectional value point set. z Half of the value difference, and determine the larger value, and the first point of the blade root and blade top cross-section value point set z Subtract the larger value from the value to obtain the coordinates of two new clipping points, and connect the two clipping points to obtain the entrance clipping line of the first rotation surface; S73: Determine whether the entrance cutting line of the first rotating surface intersects with the entrance straight line segment formed by connecting the two first points in the hub and casing type value point set or is located outside the entrance straight line segment; if so, use the entrance straight line segment as the entrance cutting line of the first rotating surface; S74: For the last blade, calculate the value between the first and last points of the blade root and blade tip cross-sectional value point set. z Half of the value difference, and determine the larger value, and set the end point of the blade root and blade tip cross-section value point set z Add the larger value to the value to obtain the coordinates of two new clipping points, and connect the two clipping points to obtain the exit clipping line of the last rotation surface; S75: Determine whether the exit cutting line of the last rotating surface intersects with the exit straight segment formed by connecting the two tail points of the hub and casing type value point set or is located outside the exit straight segment; if so, use the exit straight segment as the exit cutting line of the last blade flow channel segment; S76: Enlarge all cutting lines by a certain multiple according to their geometric center to ensure that the flow channel can be completely cut; S77: When the blade type is a turbomachinery, traverse all the clipping lines and use a rotation sweep operation on them to sweep 360 degrees to generate a closed clipping surface; when the blade type is a planar cascade, traverse all the clipping lines and use a translation sweep operation on them to translate and sweep a certain distance to generate a clipping plane; S78: For each of the revolution surfaces, use its corresponding inlet clipping surface and outlet clipping surface to perform clipping to obtain a clipped revolution surface; S79: When the inlet cutting line of the first rotating surface is located inside the inlet straight line segment, or the outlet cutting line of the last rotating surface is located inside the outlet straight line segment, the hub and casing contour curve are connected with the inlet straight line segment and the outlet straight line segment at the same endpoints to form a closed loop and create a meridian flow surface, the inlet cutting surface of the first rotating surface is used to cut the meridian flow surface to obtain the flow channel inlet surface, and the outlet cutting surface of the last rotating surface is used to cut the meridian flow surface to obtain the flow channel outlet surface.

7. The multi-row, multi-cycle, high-precision modeling method for blade mechanical flow passages according to claim 1, characterized in that: S8 includes the following sub-steps: S81: Each of the cropped rotation surfaces is rotated according to its own rotation angle or translation distance Sweep to obtain a single-period sub-flow channel segment; In rotating machinery, the sweep angle of a single-cycle sub-channel segment is calculated based on the number of blades in the blade row, using the formula: ； in is the sweep angle of the single-period sub-channel segment, In turbomachinery, it is the number of blades in a row; In a plane cascade, the distance swept by a single-period sub-channel segment is the translation distance ; S82: For a multi-cycle sub-channel segment, set the number of repetitions of the sweep cycle of the sub-channel segment. R , rotate each of the cropped rotation surfaces according to their respective rotation angles or translation distance Sweep to obtain multi-periodic sub-flow channel segments; At this time, the rotation sweep angle of the rotating surface in the impeller machine is: ； in is the rotation sweep angle of the multi-periodic sub-channel segment, is the sweep angle of the single-period sub-channel segment, R is the number of repetitions of the sweep cycle of the sub-channel segment; At this time, the translation sweep distance of the rotating surface in the plane cascade is: ； in is the translation sweep distance of the multi-periodic sub-channel segment, is the translation sweep distance of the single-period sub-channel segment, R is the number of repetitions of the sweep cycle of the sub-channel segment; S83: Sweeping the flow channel inlet surface by the same sweep angle or translation distance as the first rotation surface to generate a flow channel inlet segment, and sweeping the flow channel outlet surface by the same sweep angle or translation distance as the last rotation surface to generate a flow channel outlet segment.

8. The multi-row, multi-cycle, high-precision modeling method for blade mechanical flow passages according to claim 7, characterized in that: S9 includes the following sub-steps: S91: Traverse the blade profile cross-section set of each blade, fit the blade back and blade basin shape value point set to obtain the blade back and blade basin curves, connect the blade basin curve and blade back curve of each blade profile cross-section at the leading edge and trailing edge endpoints to form a closed blade profile cross-section ring, and use the lofting operation between the blade profile cross-section rings to generate a three-dimensional blade; S92: For the single-periodic sub-channel segments, perform a Boolean subtraction operation on each single-periodic sub-channel segment generated by a blade and its corresponding three-dimensional blade, subtracting the three-dimensional blade from the single-periodic sub-channel segment to generate a single-periodic fluid channel; S93: For the multi-periodic sub-channel segment, when the blade type is an impeller machine, each three-dimensional blade is rotated around the rotation axis. The angle of each rotation is the angle swept by the single-cycle sub-channel segment. and subtracting the three-dimensional blades before and after each rotation from each multi-periodic sub-channel segment generated by the blades to generate a multi-periodic fluid channel; S94: For the multi-periodic sub-channel segment, when the blade type is a plane cascade, each three-dimensional blade is translated in the direction of blade arrangement. times, and the distance of each translation is the distance swept by the single-cycle sub-channel segment is the translation distance And each multi-periodic sub-channel segment generated by the blade is subtracted from the three-dimensional blade before and after each translation to generate a multi-periodic fluid channel.

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