A turbine blade parameterized modeling method and system based on blade end wall integrated design

Abstract

The application belongs to the technical field of turbine blade design. The application provides a turbine blade parameterized modeling method and system based on integrated design of blade end wall. The complete three-dimensional turbine blade geometric surface is directly generated by NFFD grid in the embodiment of the disclosure, so that the high-order smooth transition between the blade and the end wall is easy to realize. The method not only supports local modification of the blade geometry, but also provides rich geometric modification deformation parameters, which facilitates determination of the adjustment range of the parameters and ensures that unreasonable geometric shapes do not occur. In the optimization design process, no additional constraint conditions need to be set, so that a flexible and efficient optimization process is realized. In addition, the method is suitable for modeling and parameterization of axial turbine blades for various purposes, and has good regulation and control effect on the end region secondary flow.

Description

Technical Field

[0001] This disclosure relates to the field of turbine blade design technology, and in particular to a parametric modeling method and system for turbine blades based on integrated endwall design. Background Technology

[0002] With the increasing demands for high load, high efficiency, and high reliability in high-performance axial turbines, blade design has become a key factor in improving turbine performance. Against this backdrop, the concept of blade endwall integration design has emerged, further driving the development of turbine technology. This design concept aims to start from the design source, deeply considering the aerodynamic relationship between turbine blades, endwalls, and flow channels. By optimizing the airflow path and improving flow distribution, it reduces flow losses and improves the overall efficiency of the turbine. The blade endwall integration design method is an important approach to achieving blade endwall integration design. This method directly obtains the airflow channel by superimposing vertical streamline sections at different flow directions, and then obtains the blade geometry through the solid enclosed by two adjacent airflow channels. This design method can greatly improve the flow deterioration problem in the blade / endwall corner region caused by traditional design methods, proactively considering the control of end-region flow from the initial design stage, thereby potentially significantly reducing secondary flow losses in the turbine end region.

[0003] However, existing integrated blade endwall design methods only achieve the flow channel shape by constructing the shape of each cross-section, with relatively little parametric work, resulting in the unresolved issue of control variables. Current design methods mainly rely on lines to generate surfaces, thus lacking sensitivity to geometric shape control. This situation makes it difficult to flexibly adjust the flow channel geometry during subsequent optimization design processes, limiting the design's potential and efficiency.

[0004] Therefore, it is necessary to improve one or more of the problems existing in the above-mentioned related technical solutions.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this disclosure is to provide a parametric modeling method and system for turbine blades based on integrated blade endwall design, thereby overcoming at least to some extent one or more problems caused by the limitations and defects of related technologies.

[0007] According to a first aspect of the present disclosure, a parametric modeling method for turbine blades based on integrated blade endwall design is provided, the method comprising:

[0008] Obtain the geometric data of the prototype blade, and based on the geometric data and the rotating surface, perform coordinate transformation on the airfoil of the prototype turbine blade to obtain a planar straight blade.

[0009] Based on the planar straight blade, the mid-arc line of the blade profile at each radial section is obtained;

[0010] The direction of the flow channel along each cross section is determined based on the slope distribution of the mid-arc line of each radial section of the straight blade, and the number of flow channel cross sections is set to determine the cutting trajectory of each cross section of the flow channel.

[0011] The discrete point coordinates of each flow channel section are extracted based on the segmentation trajectory of each flow channel section. The control points of each section are obtained by combining the NURBS inverse algorithm, and the NFFD control grid is formed based on the control points of each section.

[0012] The initial shape of the turbine planar straight blade is generated based on the NFFD control mesh, and the mesh deformation is controlled by the parameters of the NFFD control mesh to modify the initial shape of the turbine planar straight blade in order to obtain the target shape of the turbine planar straight blade.

[0013] The target shape of the turbine planar straight blade is transformed by coordinate transformation to obtain the geometry of the rotating surface turbine blade.

[0014] Further, the steps of acquiring the geometric data of the prototype blade and performing coordinate transformation on the turbine blade of the prototype blade based on the geometric data and the surface of revolution to obtain the planar straight blade include:

[0015] Obtain the geometric data of the prototype blade, determine the surface of revolution, and convert the (x,y,z) coordinates of the discrete points of the blade profile at each cross section of the prototype blade into (r,θ,z) coordinates;

[0016] Where x is the radial position of the airfoil, y is the circumferential position, and z is the axial position of the airfoil.

[0017] Furthermore, the step of obtaining the mid-arc line of each radial section of the straight blade based on the planar straight blade includes:

[0018] The blade shape is divided into suction side and pressure side based on the leading edge point and trailing edge point. The curvature distribution of the suction side and pressure side is calculated separately, and the curvature abrupt part is removed to obtain the pressure side and suction side of the blade.

[0019] The pressure side profile and suction side profile of the blade are offset at equal intervals multiple times. After each offset, several intersection points are generated. The intersection points are arranged in axial order to form a point set, which forms the middle arc line of each radial section of the straight blade.

[0020] Furthermore, the step of determining the direction of each cross-section of the flow channel along the flow direction based on the slope distribution of the mid-curve of each radial section of the straight blade, and setting the number of flow channel cross-sections to determine the cutting trajectory of each cross-section of the flow channel, includes:

[0021] Based on the preset number of flow channel sections n, the middle arc line is divided according to the uniform chord length method to obtain the dividing point;

[0022] Determine the direction of the normal to the mid-arc at each tangent point based on the slope distribution of the mid-arc.

[0023] Solve for the intersections of the normal with the pressure side profile of the blade and the suction side profile of the blade respectively, and arrange them axially;

[0024] The suction side and pressure side of each section of the blade are radially connected in axial order through the intersections of the normal and the blade pressure side profile, and the normal and the blade suction side profile, to obtain the cutting trajectory of each section of the flow channel.

[0025] Further, the steps of extracting discrete point coordinates of each flow channel section based on the segmentation trajectory of each flow channel section, obtaining control points for each section using the NURBS inverse algorithm, and constructing an NFFD control mesh based on the control points of each section include:

[0026] The coordinates of discrete points of each cross section of the flow channel are extracted based on the segmentation trajectory of each cross section;

[0027] The node vector is determined based on the discrete point coordinates of each section of the flow channel;

[0028] Constructing non-uniform B-spline basis functions based on node vectors;

[0029] Based on non-uniform B-spline basis functions and combined with the NURBS inverse algorithm, a coefficient matrix and a set of inverse equations for control points are established to obtain the control vertices of each cross-sectional curve.

[0030] The control vertices of each cross-sectional curve are arranged along the blade flow direction to form a closed NFFD control grid.

[0031] Further, the step of generating an initial shape of the turbine planar straight blade based on the NFFD control mesh, and controlling the mesh deformation using the parameters of the NFFD control mesh to modify the initial shape of the turbine planar straight blade to obtain the target shape of the turbine planar straight blade includes:

[0032] The initial shape of the turbine planar straight blades is generated based on the NFFD control mesh;

[0033] After the control points are moved, the NFFD algorithm recalculates the coordinates of the shape points of the turbine blade geometry based on the new positions of the control vertices of each cross-sectional curve.

[0034] By adding weights to local control points and modifying turbine blade details, the target shape of the turbine planar straight blade is obtained.

[0035] According to a second aspect of the present disclosure, a parametric modeling system for turbine blades based on integrated blade endwall design is provided, the system comprising:

[0036] The first blade coordinate transformation module is used to acquire the geometric data of the prototype blade and perform coordinate transformation on the turbine blade of the prototype blade according to the geometric data and the rotating surface to obtain a planar straight blade.

[0037] The blade profile geometry analysis module is used to obtain the mid-arc line of the blade profile at each radial section of a straight blade, based on a planar straight blade.

[0038] The blade flow channel segmentation module is used to determine the direction of each section of the flow channel along the flow direction based on the slope distribution of the mid-arc line of each radial section of the straight blade, and to set the number of flow channel sections to determine the segmentation trajectory of each section of the flow channel.

[0039] The NFFD control mesh generation module is used to extract the discrete point coordinates of each section of the flow channel based on the cutting trajectory of each flow channel section, combine the NURBS inverse algorithm to obtain the control points of each section, and form the NFFD control mesh based on the control points of each section.

[0040] The shape modification module is used to generate the initial shape of the turbine planar straight blade based on the NFFD control mesh, and to control the mesh deformation using the parameters of the NFFD control mesh to modify the initial shape of the turbine planar straight blade in order to obtain the target shape of the turbine planar straight blade.

[0041] The second blade coordinate transformation module is used to perform coordinate transformation on the target shape of the turbine planar straight blade to obtain the geometry of the rotating surface turbine blade.

[0042] The technical solutions provided by the embodiments of this disclosure may include the following beneficial effects:

[0043] In the embodiments of this disclosure, the above-described parametric modeling method and system for turbine blades based on integrated blade endwall design achieves the following: First, the discrete point coordinates of each section of the prototype blade are obtained by the acquisition module and used as input to the processing module. The processing module then performs coordinate transformation, airfoil geometry analysis, and blade flow channel segmentation to obtain an NFFD control mesh. The coordinate changes of each control point in the mesh are controlled by NFFD mesh deformation parameters, and the weights of the control points are adjusted to achieve deformation and fine-tuning of the turbine blade geometry. Finally, the output module outputs a final model usable for mesh generation. Second, the complete three-dimensional turbine blade geometry is directly generated using an NFFD (Non-Uniform Rational B-Spline Free-Form Deformation) mesh, making it easy to achieve a high-order smooth transition between the blade and the endwall. This method not only supports local modifications to the blade geometry but also provides rich geometric modification deformation parameters, facilitating the determination of parameter adjustment ranges and ensuring that unreasonable geometric shapes are avoided. During the optimization design process, no additional constraints are required, thus achieving a flexible and efficient optimization process. Furthermore, this method is applicable to the modeling and parametric process of axial turbine blades for various applications and has a good control effect on the secondary flow in the end region.

[0044] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0045] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0046] Figure 1 This diagram illustrates the steps of a parametric modeling method for turbine blades based on integrated blade endwall design in an exemplary embodiment of this disclosure.

[0047] Figure 2 This diagram illustrates a three-dimensional turbine guide vane in an exemplary embodiment of the present disclosure.

[0048] Figure 3 This diagram illustrates a turbine straight blade obtained after the first coordinate transformation in an exemplary embodiment of this disclosure.

[0049] Figure 4 This diagram illustrates the arc of the leaf shape in an exemplary embodiment of this disclosure;

[0050] Figure 5This diagram illustrates the intersection point between the arc normal and the airfoil profile in an exemplary embodiment of this disclosure.

[0051] Figure 6 A schematic diagram of a storage file for adjusting the geometric deformation parameters of a turbine blade in an exemplary embodiment of this disclosure is shown.

[0052] Figure 7 This diagram illustrates the NFFD control mesh and geometric model in an exemplary embodiment of this disclosure.

[0053] Figure 8 This diagram illustrates a comparison between the geometry of a turbine straight blade obtained using the method of this application and the geometry of a three-dimensional blade obtained after a second coordinate transformation, and the geometry of the prototype blade, as shown in an exemplary embodiment of this disclosure.

[0054] Figure 9 A schematic diagram illustrating the effect of turbine blades on secondary flow obtained using the method of this application in an exemplary embodiment of this disclosure;

[0055] Figure 10 The flowchart illustrating the execution of the parametric modeling system in an exemplary embodiment of this disclosure is shown. Detailed Implementation

[0056] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0057] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0058] This example implementation first provides a parametric modeling method for turbine blades based on integrated blade endwall design. This method can be applied to a terminal device, such as a mobile terminal like a smartphone, personal digital assistant, laptop, tablet, or smartwatch [adjusted flexibly according to specific circumstances, such as a server]. Reference Figure 1 As shown, the method may include the following steps:

[0059] Step S101: Obtain the geometric data of the prototype blade, and perform coordinate transformation on the blade profile of the prototype turbine blade based on the geometric data and the rotating surface to obtain a planar straight blade.

[0060] Step S102: Based on the planar straight blade, obtain the mid-arc line of the blade profile at each radial section of the straight blade;

[0061] Step S103: Determine the direction of each section of the flow channel along the flow direction based on the slope distribution of the mid-arc line of each radial section of the straight blade, and set the number of flow channel sections to determine the cutting trajectory of each section of the flow channel;

[0062] Step S104: Extract the discrete point coordinates of each section of the flow channel based on the segmentation trajectory of each flow channel section, obtain the control points of each section by combining the NURBS inverse algorithm, and form an NFFD control grid based on the control points of each section.

[0063] Step S105: Generate the initial shape of the turbine planar straight blade according to the NFFD control mesh, and use the parameters of the NFFD control mesh to control the mesh deformation and modify the initial shape of the turbine planar straight blade to obtain the target shape of the turbine planar straight blade.

[0064] Step S106: Perform coordinate transformation on the target shape of the turbine planar straight blade to obtain the geometry of the rotating surface turbine blade.

[0065] The parametric modeling method for turbine blades based on integrated blade endwall design described above achieves two main objectives. First, the acquisition module obtains the discrete coordinates of each section of the prototype blade, which serve as input to the processing module. The processing module then performs coordinate transformation, airfoil geometry analysis, and blade flow channel segmentation to obtain an NFFD control mesh. The coordinate changes of each control point in the mesh are controlled by NFFD mesh deformation parameters, and the weights of these control points are adjusted to achieve turbine blade geometry deformation and fine-tuning. Finally, the output module outputs a final model suitable for mesh generation. Second, the method directly generates a complete 3D turbine blade geometry using the NFFD mesh, facilitating a smooth, high-order transition between the blade and endwall. This method not only supports local modifications to the blade geometry but also provides a wealth of geometric deformation parameters (including numerous dimensionless parameters), making it easy to determine the adjustment range of the parameters and ensuring that unreasonable geometric shapes are avoided. During the optimization design process, no additional constraints are required, enabling a flexible and efficient optimization process. Furthermore, this method is applicable to the modeling and parametric process of axial turbine blades for various applications and exhibits excellent control over secondary flow in the end region.

[0066] Below, we will refer to Figures 1 to 9 The steps of the method described above in this example embodiment will be explained in more detail.

[0067] In step S101, the geometric data of the prototype blade is obtained, and the turbine blade of the prototype blade is transformed according to the geometric data and the rotating surface to obtain a planar straight blade.

[0068] For example, the geometric data of the prototype blade is obtained, and the (x, y, z) coordinates of discrete points on each cross-section of the prototype blade are converted into (r, θ, z) coordinates. Here, x represents the radial position of the blade, y represents the circumferential position, and z represents the axial position; when the rotating surface is cylindrical, r is the radius of the cylindrical coordinate system, and θ is the azimuth angle of the discrete point, ranging from 0 to 2π. This first coordinate transformation converts the rotating turbine blade into a planar straight blade.

[0069] In one embodiment, a prototype blade is obtained (see...). Figure 2 The geometric data of the prototype blade is used to transform the (x,y,z) coordinates of discrete points on each cross-section of the blade into (r,θ,z) coordinates. Taking the cylindrical surface of revolution as an example, the coordinate transformation satisfies: θ = arctan(x / y). After the first coordinate transformation, the rotating turbine blade can be converted into a planar straight blade. See [reference needed]. Figure 3 .

[0070] In steps S102 and S103, the mid-arc line of each radial section of the straight blade is obtained based on the planar straight blade; the direction of each section of the flow channel along the flow direction is determined based on the slope distribution of the mid-arc line of each radial section of the straight blade, and the number of flow channel sections is set to determine the cutting trajectory of each section of the flow channel.

[0071] For example, the mid-arc line of each radial section of the straight blade is solved. The slope distribution of the mid-arc line can determine the direction of each section of the flow channel along the flow direction. After setting the number of flow channel sections, the cutting trajectory of each section of the flow channel is determined.

[0072] In one embodiment, the blade shape is divided into two parts, suction side and pressure side, based on the leading edge point and trailing edge point. The curvature distribution of these two parts is solved separately, and the parts with abrupt curvature changes are removed, that is, the pressure side and suction side of the blade are retained.

[0073] The pressure and suction sides of the blade profile are offset multiple times at equal intervals, producing 1-2 intersection points after each offset. These intersection points are arranged sequentially along the axial direction to form a point set. The profile formed by this point set is the mid-curve of the blade. (See [reference]) Figure 4 .in, Figure 4 (a) shows the solution for the arc of the leaf tip profile. Figure 4 (b) shows the solution for the arc in the leaf root leaf shape.

[0074] Based on the given number of flow channel sections n, the middle arc is divided according to the uniform chord length method to obtain the dividing points. Then, the normal direction of the middle arc at each dividing point is determined according to the slope distribution of the middle arc.

[0075] Solve for the intersections of the normal with the pressure side profile of the blade and the normal with the suction side profile of the blade, and arrange them axially.

[0076] Connecting the suction and pressure sides of each blade cross-section radially through the intersection points obtained in the previous step in axial order yields the cutting trajectory of each cross-section of the flow channel. (See [link to previous section]). Figure 5 .in, Figure 5 (a) shows the solution for the leaf tip leaf shape segmentation point. Figure 5 (b) shows the solution results for the leaf root leaf shape segmentation point.

[0077] In a specific embodiment, assuming the arc is defined on the interval [a, b], the arc length is calculated using the integral formula. in Let be the slope of the mid-arc. Dividing the mid-arc into 10 equal segments means that the arc length of each segment is .

[0078] Calculating the dividing point requires ensuring that the arc length of each segment is equal. Let i = 1, ... 10, and solve the equation... Obtain the coordinates of the dividing point.

[0079] At each dividing point, calculate the slope of the mid-arc, i.e., the derivative. The direction of the normal can be determined by determining the slope of the arc at each tangent point.

[0080] In step S104, the discrete point coordinates of each flow channel section are extracted based on the segmentation trajectory of each flow channel section. The control points of each section are obtained by combining the NURBS inverse algorithm, and the NFFD control grid is formed based on the control points of each section.

[0081] For example, the discrete point coordinates of each flow channel section are extracted from the segmentation trajectory of each flow channel section. The control points of each section can be obtained from the discrete point coordinates using the NURBS inverse algorithm. These control points form a preliminary NFFD control grid.

[0082] More specifically, the node vectors are determined based on the discrete point coordinates of each cross section of the flow channel, and the node vectors are used to construct non-uniform B-spline basis functions.

[0083] Establish a coefficient matrix and a set of back-calculation equations for control points to obtain the control vertices of each cross-sectional curve.

[0084] The control points of each section are arranged along the blade flow direction to form a closed NFFD control grid.

[0085] In one embodiment, based on the discrete point coordinates q of each cross-section of the flow channel i,j To determine the node vector U, use the node vector to construct a non-uniform B-spline basis function:

[0086]

[0087] By establishing the coefficient matrix and the inverse equation system for the control points, the control vertices of each cross-sectional curve are obtained:

[0088]

[0089] Where, d i,j These are control points.

[0090] The control points of each section are arranged along the blade flow direction to form a closed NFFD control grid.

[0091] In step S105, the initial shape of the turbine planar straight blade is generated according to the NFFD control mesh, and the mesh deformation is controlled by the parameters of the NFFD control mesh to modify the initial shape of the turbine planar straight blade, so as to obtain the target shape of the turbine planar straight blade.

[0092] For example, the coordinate changes of each control point in the control mesh are controlled according to the NFFD mesh deformation parameters. When the control point is moved, the NFFD algorithm will recalculate the coordinates of the shape point of the turbine blade geometry based on the new position of the control point.

[0093] Weights are added to local control points, and turbine blade details are modified.

[0094] In one embodiment, based on NFFD mesh deformation parameters (see...) Figure 6 The coordinates of each control point in the control mesh change. When a control point is moved, the NFFD algorithm recalculates the coordinates of the shape points of the turbine blade geometry based on the new position of the control point.

[0095]

[0096] Where P is the (r, θ, z) rectangular coordinate vector of a point on the straight blade geometric model.

[0097] Add weight W to the local control points i,j,k Modifications were made to the turbine blade details; see [link / reference]. Figure 7 .in, Figure 7 (a) and (b) are schematic diagrams of the blade shape from two different perspectives.

[0098] In step S106, the target shape of the turbine planar straight blade is transformed by coordinate transformation to obtain the geometry of the rotating surface turbine blade.

[0099] For example, the turbine straight blade obtained in step S105 is subjected to a second coordinate transformation to obtain the geometry of the rotating surface turbine blade, which is the final result.

[0100] In one embodiment, the (r, θ, z) coordinates of discrete points on each cross-section of the straight blade are transformed into (x, y, z) coordinates. Taking the cylindrical surface of revolution as an example, the coordinate transformation satisfies: x = rsinθ, y = rcosθ. The final result can be obtained after a second coordinate transformation. See [link to documentation]. Figure 8 .in, Figure 8 (a) Comparison of the resulting design of the slewing blade with the prototype blade. Figure 8 (b) shows a comparison between the design result of the planar straight blade and the prototype blade.

[0101] like Figure 9 The image shows a schematic diagram illustrating the effect of a turbine blade on secondary flow, obtained using a parametric modeling method based on integrated blade endwall design. Among these, Figure 9 (a) is a contour map of the axial vorticity distribution of the prototype blade. Figure 9 (b) is a cloud map of the axial vorticity distribution of the blade obtained using the present invention.

[0102] It should be noted that although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that these steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps. Furthermore, it is readily understood that these steps may be executed synchronously or asynchronously, for example, in multiple modules / processes / threads.

[0103] Furthermore, this example embodiment also provides a parametric modeling system for turbine blades based on integrated blade endwall design. This parametric modeling system for turbine blades based on integrated blade endwall design may include a first blade coordinate transformation module, an airfoil geometry analysis module, a blade flow channel segmentation module, an NFFD control mesh generation module, a shape modification module, and a second blade coordinate transformation module. Wherein:

[0104] The first blade coordinate transformation module is used to acquire the geometric data of the prototype blade and perform coordinate transformation on the turbine blade of the prototype blade according to the geometric data and the rotating surface to obtain a planar straight blade.

[0105] The blade profile geometry analysis module is used to obtain the mid-arc line of the blade profile at each radial section of a straight blade, based on a planar straight blade.

[0106] The blade flow channel segmentation module is used to determine the direction of each section of the flow channel along the flow direction based on the slope distribution of the mid-arc line of each radial section of the straight blade, and to set the number of flow channel sections to determine the segmentation trajectory of each section of the flow channel.

[0107] The NFFD control mesh generation module is used to extract the discrete point coordinates of each section of the flow channel based on the cutting trajectory of each flow channel section, combine the NURBS inverse algorithm to obtain the control points of each section, and form the NFFD control mesh based on the control points of each section.

[0108] The shape modification module is used to generate the initial shape of the turbine planar straight blade based on the NFFD control mesh, and to control the mesh deformation using the parameters of the NFFD control mesh to modify the initial shape of the turbine planar straight blade in order to obtain the target shape of the turbine planar straight blade.

[0109] The second blade coordinate transformation module is used to perform coordinate transformation on the target shape of the turbine planar straight blade to obtain the geometry of the rotating surface turbine blade.

[0110] Specifically, such as Figure 10 The diagram shows the flowchart of a parametric modeling system for turbine blades based on integrated blade endwall design. The input module is the first blade coordinate transformation module; the processing modules include the airfoil geometry analysis module, the blade flow channel segmentation module, the NFFD control mesh generation module, and the shape modification module; the output module is the second blade coordinate transformation module.

[0111] The aforementioned parametric modeling method and system for turbine blades based on integrated blade endwall design achieves the following: First, the discrete point coordinates of each section of the prototype blade are obtained by the acquisition module and used as input to the processing module. The processing module then performs coordinate transformation, airfoil geometry analysis, and blade flow channel segmentation to obtain an NFFD control mesh. The coordinate changes of each control point in the mesh are controlled by NFFD mesh deformation parameters, and the weights of the control points are adjusted to achieve deformation and fine-tuning of the turbine blade geometry. Finally, the output module outputs a final model suitable for mesh generation. Second, the complete three-dimensional turbine blade geometry is directly generated using the NFFD mesh, making it easy to achieve a smooth, high-order transition between the blade and the endwall. This method not only supports local modifications to the blade geometry but also provides a wealth of geometric modification deformation parameters (including numerous dimensionless parameters), facilitating the determination of parameter adjustment ranges and ensuring the avoidance of unreasonable geometric shapes. During the optimization design process, no additional constraints are required, enabling a flexible and efficient optimization process. Furthermore, this method is applicable to the modeling and parametric processes of axial turbine blades for various applications and exhibits excellent control over secondary flow in the end region.

[0112] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0113] It should be noted that although several modules or units for the device used to perform actions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units. Components shown as modules or units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this disclosure according to actual needs. Those skilled in the art can understand and implement this without any inventive effort.

[0114] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A parametric modeling method for turbine blades based on integrated endwall design, characterized in that, The method includes: Obtain the geometric data of the prototype blade, and based on the geometric data and the rotating surface, perform coordinate transformation on the airfoil of the prototype turbine blade to obtain a planar straight blade. Based on the planar straight blade, the mid-arc line of the blade profile at each radial section is obtained; The direction of the flow channel along each cross section is determined based on the slope distribution of the mid-arc line of each radial section of the straight blade, and the number of flow channel cross sections is set to determine the cutting trajectory of each cross section of the flow channel. Specifically, this includes: dividing the mid-arc line according to the uniform chord length method based on the preset number of flow channel cross sections n to obtain the cutting points; determining the normal direction of the mid-arc line at each cutting point based on the slope distribution of the mid-arc line; solving for the intersection points of the normal line with the pressure side profile of the blade body and the suction side profile of the blade body respectively, and arranging them axially; and radially connecting the suction side and pressure side of each blade cross section through the intersection points of the normal line with the pressure side profile of the blade body and the suction side profile of the blade body in axial order to obtain the cutting trajectory of each cross section of the flow channel. The discrete point coordinates of each flow channel section are extracted based on the segmentation trajectory of each flow channel section. The control points of each section are then obtained using the NURBS inverse algorithm, and an NFFD control grid is formed based on these control points. Specifically, this includes: extracting the discrete point coordinates of each flow channel section based on the segmentation trajectory; determining the node vectors based on the discrete point coordinates of each flow channel section; constructing non-uniform B-spline basis functions based on the node vectors; establishing a coefficient matrix and a set of inverse equations for control points based on the non-uniform B-spline basis functions and the NURBS inverse algorithm to obtain the control vertices of each section curve; and arranging the control vertices of each section curve along the blade flow direction to form a closed NFFD control grid. The initial shape of the turbine planar straight blade is generated based on the NFFD control mesh, and the mesh deformation is controlled by the parameters of the NFFD control mesh to modify the initial shape of the turbine planar straight blade to obtain the target shape of the turbine planar straight blade. Specifically, this includes: generating the initial shape of the turbine planar straight blade based on the NFFD control mesh; when the control points move, the NFFD algorithm recalculates the shape point coordinates of the turbine blade geometry based on the new positions of the control vertices of each cross-sectional curve; adding weights to local control points and modifying the details of the turbine blade to obtain the target shape of the turbine planar straight blade. The target shape of the turbine planar straight blade is transformed by coordinate transformation to obtain the geometry of the rotating surface turbine blade.

2. The parametric modeling method for turbine blades based on integrated endwall design according to claim 1, characterized in that, The steps of acquiring the geometric data of the prototype blade and performing coordinate transformation on the blade profile of the prototype turbine blade based on the geometric data and the surface of revolution to obtain a planar straight blade include: Obtain the geometric data of the prototype blade, determine the surface of revolution, and discretize the airfoil points of each section of the prototype blade. x,y,z ) coordinates converted to ( r,θ,z )coordinate; in, x This refers to the radial position of the leaf shape. y Circumferential position, z This refers to the axial position of the airfoil.

3. The parametric modeling method for turbine blades based on integrated endwall design according to claim 1, characterized in that, The steps for obtaining the mid-arc line of each radial section of a straight blade, based on a planar straight blade, include: The blade shape is divided into suction side and pressure side based on the leading edge point and trailing edge point. The curvature distribution of the suction side and pressure side is calculated separately, and the curvature abrupt part is removed to obtain the pressure side and suction side of the blade. The pressure side profile and suction side profile of the blade are offset at equal intervals multiple times. After each offset, several intersection points are generated. The intersection points are arranged in axial order to form a point set, which forms the middle arc line of each radial section of the straight blade.

4. A parametric modeling system for turbine blades based on integrated endwall design, characterized in that, The system includes: The first blade coordinate transformation module is used to acquire the geometric data of the prototype blade and perform coordinate transformation on the turbine blade of the prototype blade according to the geometric data and the rotating surface to obtain a planar straight blade. The blade profile geometry analysis module is used to obtain the mid-arc line of the blade profile at each radial section of a straight blade, based on a planar straight blade. The blade flow channel segmentation module is used to determine the direction of each flow channel section along the flow direction based on the slope distribution of the mid-curve of each radial section of the straight blade, and to set the number of flow channel sections to determine the segmentation trajectory of each flow channel section. Specifically, it includes: segmenting the mid-curve according to the preset number of flow channel sections n using the uniform chord length method to obtain the segmentation points; determining the normal direction of the mid-curve at each segmentation point based on the slope distribution of the mid-curve; solving for the intersection points of the normal with the blade pressure side profile and the blade suction side profile respectively, and arranging them axially; and radially connecting the suction side and pressure side of each blade section through the intersection points of the normal with the blade pressure side profile and the blade suction side profile in axial order to obtain the segmentation trajectory of each flow channel section. The NFFD control mesh generation module is used to extract the discrete point coordinates of each cross-section of the flow channel based on the cutting trajectory of each cross-section, obtain the control points of each cross-section using the NURBS inverse algorithm, and form an NFFD control mesh based on the control points of each cross-section. Specifically, it includes: extracting the discrete point coordinates of each cross-section of the flow channel based on the cutting trajectory of each cross-section; determining the node vector based on the discrete point coordinates of each cross-section of the flow channel; constructing a non-uniform B-spline basis function based on the node vector; establishing a coefficient matrix and a set of inverse equations for control points based on the non-uniform B-spline basis function and the NURBS inverse algorithm to obtain the control vertices of each cross-section curve; and arranging the control vertices of each cross-section curve along the blade flow direction to form a closed NFFD control mesh. The shape modification module is used to generate the initial shape of the turbine planar straight blade based on the NFFD control mesh, and to control the mesh deformation using the parameters of the NFFD control mesh to modify the initial shape of the turbine planar straight blade to obtain the target shape of the turbine planar straight blade. Specifically, it includes: generating the initial shape of the turbine planar straight blade based on the NFFD control mesh; when the control points move, the NFFD algorithm recalculates the shape value point coordinates of the turbine blade geometry based on the new positions of the control vertices of each cross-sectional curve; adding weights to local control points and modifying the details of the turbine blade to obtain the target shape of the turbine planar straight blade. The second blade coordinate transformation module is used to perform coordinate transformation on the target shape of the turbine planar straight blade to obtain the geometry of the rotating surface turbine blade.

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