A method for distinguishing blade part and non-blade part of a rotating mechanical component

Abstract

The present invention discloses a method for distinguishing blade parts and non-blade parts of a rotating mechanical component, and relates to the field of computer-aided design. The method comprises: obtaining geometric information of the rotating mechanical component to be distinguished; identifying arcs contained therein and the center of a circle corresponding to the arcs; determining the rotation axis of the rotating mechanical component to be distinguished; performing grid division on the rotating mechanical component to be distinguished to obtain point data; projecting the point data onto a two-dimensional plane according to the distance between the point data and the rotation axis to obtain projected point data; obtaining a total boundary line and each partial boundary line according to the projected data of all point data projected onto the two-dimensional plane and the projected data of part of the point data; distinguishing the blade part and non-blade part of the total boundary line to obtain a distinguishing result. The present invention can automatically, simply, efficiently and accurately distinguish the working flow domain of the rotating mechanical component.

Description

Technical Field

[0001] The invention relates to the field of computer-aided design, and in particular to a method for distinguishing a blade part and a non-blade part of a rotating mechanical component. Background Art

[0002] Before the rotating mechanical components in the CAD software are imported into the CAE software for simulation, the rotating mechanical components need to be divided, that is, the watershed involved in the operation of the rotating mechanical components needs to be divided. At present, the accuracy of watershed division will affect the simulation results when the CAE software simulates the operation of the rotating mechanical components, including the convergence and accuracy of the simulation calculation in the CAE software. Therefore, improving the accuracy of watershed division is a technical problem that needs to be solved urgently. Summary of the invention

[0003] The object of the present invention is to provide a method for distinguishing the blade part and the non-blade part of a rotating machinery component, which can automatically, simply, efficiently and accurately distinguish the working flow domain of the rotating machinery component.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] A method for distinguishing a blade part and a non-blade part of a rotating machinery component, the method comprising:

[0006] Acquire a CAD model of a rotating mechanical component to be distinguished and geometric information of the CAD model;

[0007] Determining the rotation axis of the rotating mechanical component to be distinguished according to the geometric information;

[0008] Meshing the rotating mechanical parts to be distinguished to obtain point data;

[0009] According to the distance between the point data and the rotation axis and the distance between the point data and the plane where the position point of the rotation axis is located, the point data is projected onto a two-dimensional plane to obtain projected point data; wherein the projected point data includes a group of projected data of all point data and multiple groups of projected data of partial point data; the plane where the position point of the rotation axis is located is perpendicular to the rotation axis;

[0010] Obtaining a corresponding total boundary line and each partial boundary line according to the projected data of all the point data and the projected data of the partial point data projected on the two-dimensional plane;

[0011] According to the correspondence between the total boundary line and each of the partial boundary lines, the blade part and the non-blade part of the total boundary line are distinguished to obtain the distinction result of the rotating mechanical component to be distinguished.

[0012] Optionally, determining the rotation axis of the rotating mechanical component to be distinguished according to the geometric information specifically includes:

[0013] According to the geometric information, a plurality of closed arcs included in the rotating mechanical component to be distinguished are identified and the center of each closed arc is determined; each closed arc is composed of a plurality of arcs connected end to end and the sum of the center angles of each arc is 360 degrees;

[0014] The rotation axis of the to-be-differentiated rotating mechanical component is determined according to the center of the circle.

[0015] Optionally, determining the rotation axis of the to-be-differentiated rotating mechanical component according to the center of the circle specifically includes:

[0016] The number of the circle centers includes a plurality, and the directions of the vectors formed by the lines connecting the circle centers are determined to obtain a plurality of direction vectors;

[0017] Counting the number of the direction vectors in each direction among the plurality of direction vectors; wherein the direction vectors with the same direction and the direction vectors with opposite directions are regarded as direction vectors in the same direction;

[0018] The rotation axis of the rotating mechanical component to be distinguished is determined according to the direction corresponding to the direction vector with the largest number.

[0019] Optionally, gridding the rotating mechanical parts to be distinguished to obtain point data specifically includes:

[0020] Performing mesh division on the rotating mechanical parts to be distinguished to obtain an initial mesh;

[0021] According to the density of the initial grid, determining whether to encrypt the initial grid;

[0022] When the density of the initial grid is less than a preset threshold, each grid in the initial grid is meshed again to obtain a final grid;

[0023] When the density of the initial grid is greater than or equal to the preset threshold, determining the initial grid as the final grid;

[0024] Each vertex of the final mesh is determined as the point data.

[0025] Optionally, the process of acquiring the projected data of the plurality of groups of partial point data specifically includes:

[0026] Taking the rotation axis as the intersection line, applying a plurality of intersection surfaces including the intersection line to divide the point data of the rotating mechanical component to be distinguished into a plurality of parts; wherein the angles between adjacent intersection surfaces are consistent;

[0027] The point data of each portion are projected onto the two-dimensional plane respectively to obtain multiple groups of projected data of the portion point data.

[0028] Optionally, according to the correspondence between the total boundary line and each of the partial boundary lines, the blade part and the non-blade part of the total boundary line are distinguished to obtain the distinction result of the rotating machinery parts to be distinguished, specifically including:

[0029] Counting a first proportion of the projected point data in the total boundary line belonging to the partial boundary line within a first preset distance;

[0030] When the value of the first proportion is greater than the first preset proportion value, the projected point data in the corresponding total boundary line belongs to the non-leaf part;

[0031] When the value of the first proportion is less than or equal to the first preset proportion value, the projected point data in the corresponding total boundary line belongs to the blade part;

[0032] According to the blade part, the non-blade part and the rotating shaft, a distinction result of the blade part and the non-blade part of the rotating mechanical component to be distinguished is obtained.

[0033] Optionally, after executing the step of “distinguishing the blade part and the non-blade part of the total boundary line according to the correspondence between the total boundary line and each of the partial boundary lines to obtain the differentiation result of the rotating machinery component to be differentiated”, the method further includes:

[0034] The projected point data within a preset distance from each intersection point of the blade part and the non-blade part on the total boundary line is used as data to be encrypted;

[0035] Applying a linear interpolation encryption method to encrypt the boundary data to be encrypted to obtain first boundary data; the first boundary data includes the encrypted initial boundary data of the leaf part and the initial boundary data of the non-leaf part;

[0036] The projected point data of each of the partial boundary lines within a preset distance from the nearest projected point data of the intersection point is used as the data to be encrypted for each of the partial boundary lines;

[0037] Encrypting the data to be encrypted of each group of the partial point data using a linear interpolation encryption method to obtain second boundary data of each group of the partial point data;

[0038] Counting a second proportion of the first boundary data belonging to the second boundary data within a second preset distance;

[0039] When the value of the second proportion is greater than the second preset proportion value, the corresponding first boundary data belongs to the non-leaf part;

[0040] When the value of the second proportion is less than or equal to the second preset proportion, the corresponding first boundary data belongs to the blade part; wherein the second preset proportion is greater than the first preset proportion; and the second preset distance is less than the first preset distance;

[0041] When there is geometric point projection data within the third preset distance of the intersection point, the geometric point projection data is applied to update the intersection point; the geometric point projection data is the point data after the geometric point of the rotating mechanical component to be distinguished is projected in the two-dimensional plane.

[0042] Optionally, after executing the step of “distinguishing the blade part and the non-blade part of the total boundary line according to the correspondence between the total boundary line and each of the partial boundary lines to obtain the differentiation result of the rotating machinery component to be differentiated”, the method further includes:

[0043] The intersection point is kept unchanged, and the expanded point data is added in the corresponding area of ​​the leaf part to obtain the updated initial boundary data of the leaf part.

[0044] Optionally, according to the correspondence between the total boundary line and each of the partial boundary lines, the blade part and the non-blade part of the total boundary line are distinguished to obtain the distinction result of the rotating machinery parts to be distinguished, specifically including:

[0045] determining a boundary line of the blade portion according to initial boundary data of the blade portion;

[0046] Determining a boundary line of the non-blade portion according to initial boundary data of the non-blade portion;

[0047] Dividing the blade part and the non-blade part into a plurality of groups of boundary point data according to corresponding preset angle thresholds;

[0048] Generate corresponding geometric edges according to each group of boundary point data;

[0049] Determining a geometric surface according to the geometric edges of the blade portion and the geometric edges of the non-blade portion;

[0050] The geometric surface rotates once with the rotation axis as the center to obtain the distinction result of the blade part and the non-blade part.

[0051] Optionally, after executing the step of “distinguishing the blade part and the non-blade part of the total boundary line according to the correspondence between the total boundary line and each of the partial boundary lines to obtain the differentiation result of the rotating machinery component to be differentiated”, the method further includes:

[0052] The non-leaf portion is retracted by a preset retraction distance along a direction inside the region where the projected point data is located.

[0053] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0054] The present invention first obtains the CAD model of the rotating mechanical component to be distinguished and the geometric information of the CAD model; according to the geometric information, the rotation axis of the rotating mechanical component to be distinguished is determined, and the rotating mechanical component to be distinguished is gridded to obtain point data; wherein the point data is the grid intersection of the rotating mechanical component to be distinguished; then, according to the distance between the point data and the rotation axis and the distance between the point data and the plane where the position point of the rotation axis is located, the point data is projected onto a two-dimensional plane to obtain the point data after projection of the point data on the two-dimensional plane; wherein the intersection is the intersection of the rotation axis and the two-dimensional plane; the projected point data includes a group of projected data of all point data and multiple groups of projected data of partial point data; then, according to the projected data of all point data projected on the two-dimensional plane and the projected data of partial point data, the corresponding total boundary line and each partial boundary line are obtained; according to the corresponding relationship between the total boundary line and each partial boundary line, the blade part and the non-blade part of the total boundary line are distinguished to obtain the distinction result of the rotating mechanical component to be distinguished, thereby improving the distinction accuracy of the rotating working flow domain of the rotating mechanical component. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0056] Figure 1 A schematic diagram of the position of the rotating shaft of a rotating mechanical component provided in Example 1 of the present invention;

[0057] Figure 2 A schematic diagram of point data projected onto a two-dimensional plane provided in Example 1 of the present invention;

[0058] Figure 3 A schematic diagram of the overall boundary line of a rotating mechanical component provided in Example 1 of the present invention;

[0059] Figure 4 A schematic diagram of partial data boundary lines of a rotating mechanical component provided in Example 1 of the present invention;

[0060] Figure 5 A schematic diagram of the initial boundary line distinction result of the blade part and the non-blade part of the rotating machinery component provided in Example 1 of the present invention;

[0061] Figure 6 A schematic diagram showing the difference between the blade part and the non-blade part of the rotating machinery component provided in Example 1 of the present invention;

[0062] Figure 7 A schematic flow chart of a method for distinguishing between a blade portion and a non-blade portion of a rotating mechanical component provided in Example 1 of the present invention;

[0063] Figure 8 A schematic diagram of a segmented body generated according to Embodiment 1 of the present invention;

[0064] Fig. 9 The impeller provided in Example 1 of the present invention is a schematic diagram of the non-blade part;

[0065] Fig.10 A schematic diagram of the segmentation result of the impeller using the generated segmented body provided in Example 1 of the present invention;

[0066] Fig.11 A schematic diagram of a segmentation result of a segmentation surface generated for an impeller provided in Example 1 of the present invention;

[0067] Fig.12 A schematic diagram of the structure of an impeller provided in Example 1 of the present invention;

[0068] Fig.13 A schematic diagram of the retraction of the non-blade portion of the impeller provided in Example 1 of the present invention;

[0069] Fig.14 A schematic diagram of the outward expansion of the blade portion of the impeller provided in Example 1 of the present invention;

[0070] Fig.15 A schematic diagram of a partial data boundary line of an impeller provided in Example 1 of the present invention;

[0071] Fig.16 Another partial data boundary line schematic diagram of the impeller provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0072] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0073] The object of the present invention is to provide a method for distinguishing the blade part and the non-blade part of a rotating machinery component, aiming to automatically, simply, efficiently and accurately distinguish the working flow domain of the rotating machinery component.

[0074] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0075] Example 1

[0076] like Figure 7 As shown, the method for distinguishing the blade part and the non-blade part of the rotating machinery component in this embodiment includes:

[0077] Step S1: Acquire the CAD model of the rotating machinery component to be distinguished and the geometric information of the CAD model.

[0078] Step S2: Determine the rotation axis of the rotating mechanical component to be distinguished according to the geometric information.

[0079] S2 specifically includes:

[0080] Step S21: According to the geometric information, identify multiple closed arcs contained in the rotating mechanical component to be distinguished and determine the center of each closed arc; the closed arcs are composed of multiple arcs connected end to end and the sum of the center angles of each arc is 360 degrees.

[0081] Step S22: determining the rotation axis of the rotating mechanical component to be distinguished according to the center of the circle.

[0082] S22 specifically includes:

[0083] Step S221: There are multiple centers of the circle, and the directions of the vectors formed by the lines connecting the centers of the circle are determined to obtain multiple direction vectors.

[0084] Step S222: Count the number of the direction vectors in each direction among the plurality of direction vectors; wherein the direction vectors with the same direction and the direction vectors with opposite directions are regarded as direction vectors in the same direction.

[0085] Step S223: determining the rotation axis of the rotating mechanical component to be distinguished according to the direction corresponding to the direction vector with the largest number.

[0086] Step S3: gridding the rotating mechanical components to be distinguished to obtain point data; the point data are grid intersections of the rotating mechanical components to be distinguished.

[0087] S3 specifically includes:

[0088] Step S31: meshing the rotating mechanical parts to be distinguished to obtain an initial mesh.

[0089] Step S32: judging whether to encrypt the initial grid according to the density of the initial grid.

[0090] Step S33: when the density of the initial grid is less than a preset threshold, each grid in the initial grid is divided again to obtain a final grid.

[0091] Step S34: when the density of the initial grid is greater than or equal to the preset threshold, determining the initial grid as the final grid.

[0092] Step S35: Determine each vertex of the final mesh as the point data.

[0093] Step S4: Project the point data onto a two-dimensional plane according to the distance between the point data and the rotation axis and the distance between the point data and the plane where the position point of the rotation axis is located, and obtain the point data after projection of the point data on the two-dimensional plane; wherein the projected point data includes a group of projected data of all point data and multiple groups of projected data of partial point data; the plane where the position point of the rotation axis is located is perpendicular to the rotation axis. Figure 2 , Figure 3 and Figure 4 shown.

[0094] Optionally, the coordinate system corresponding to the two-dimensional plane is an XY coordinate system, and the distance between the point data and the rotation axis is the X coordinate, and the distance between the point data and the plane where the position point of the rotation axis is located is the Y coordinate, or the distance between the point data and the rotation axis is the Y coordinate, and the distance between the point data and the plane where the position point of the rotation axis is located is the X coordinate.

[0095] The process of obtaining the projected data of the plurality of groups of partial point data specifically includes:

[0096] Step S401: taking the rotation axis as the intersection line, applying a plurality of intersection surfaces including the intersection line to divide the point data of the rotating mechanical component to be distinguished into a plurality of parts; wherein the angles between adjacent intersection surfaces are consistent.

[0097] Step S402: projecting the point data of each portion onto the two-dimensional plane respectively to obtain multiple groups of projected data of the portion of point data.

[0098] Step S5: Obtain the corresponding total boundary line and each partial boundary line according to the projected data of all the point data projected on the two-dimensional plane and the projected data of the partial point data.

[0099] Step S6: according to the correspondence between the total boundary line and each of the partial boundary lines, the blade part and the non-blade part of the total boundary line are distinguished to obtain the distinction result of the rotating mechanical component to be distinguished.

[0100] S6 specifically includes:

[0101] Step S61: Counting a first proportion of the projected point data in the total boundary line belonging to the partial boundary line within a first preset distance.

[0102] Step S62: When the value of the first proportion is greater than the first preset proportion value, the projected point data in the corresponding total boundary line belongs to the non-leaf part.

[0103] Step S63: When the value of the first proportion is less than or equal to the first preset proportion, the projected point data in the corresponding total boundary line belongs to the blade part.

[0104] Step S64: obtaining a distinction result of the blade part and the non-blade part of the rotating mechanical component to be distinguished according to the blade part, the non-blade part and the rotating shaft.

[0105] S64 specifically includes:

[0106] Step S641: Divide the blade part and the non-blade part into multiple groups of boundary point data according to corresponding preset angle thresholds.

[0107] Step S642: Generate corresponding geometric edges according to each group of boundary point data.

[0108] Step S643: Determine a geometric surface according to the geometric edges of the blade part and the geometric edges of the non-blade part.

[0109] Step S644: the geometric surface is rotated once with the rotation axis as the center to obtain the distinction result between the blade part and the non-blade part.

[0110] In practical applications, the blade and non-blade parts of the total boundary line are divided into several data segments according to preset angles, and corresponding geometric edges are created based on these points in the several data segments, and then geometric faces are created. Finally, a rotation is performed around the rotation axis to generate a segmented geometric face or body.

[0111] Specifically, when a sudden change occurs in the trend of the total boundary line, the sudden change point is used as a dividing point, that is, the projection point data on the total boundary line before and after the sudden change is divided into two parts at the sudden change point.

[0112] Furthermore, the mutation situation can be judged by judging the angle between three consecutive projected point data on the total boundary line. For example, the three consecutive projected point data are the first data, the second data and the third data respectively; then the vector composed of the second data and the first data is used as the first side of the angle, and the vector composed of the third and the second data is used as the second side of the angle. It is judged whether the angle is greater than the preset value, and it is judged whether the angle is greater than the angle between the three consecutive projected point data at the beginning of the data segment where the first data is located. When both are true, the second data is the mutation point, and the second data is used as the projected point data at the beginning of the next data segment.

[0113] As a specific implementation, after executing step S6, the method further includes:

[0114] 1. The projected point data within a preset distance of each intersection point between the blade part and the non-blade part on the total boundary line is used as the data to be encrypted.

[0115] 2. Use a linear interpolation encryption method to encrypt the boundary data to be encrypted to obtain first boundary data; the first boundary data includes the encrypted initial boundary data of the leaf part and the initial boundary data of the non-leaf part.

[0116] 3. The projected point data of each of the partial boundary lines within a preset distance from the nearest projected point data of the intersection point is used as the data to be encrypted for each of the partial boundary lines.

[0117] 4. Use a linear interpolation encryption method to encrypt the data to be encrypted of each group of the partial point data to obtain the second boundary data of each group of the partial point data.

[0118] 5. Count a second proportion of the first boundary data within a second preset distance that belongs to the second boundary data.

[0119] 6. When the value of the second proportion is greater than the second preset proportion value, the corresponding first boundary data belongs to the non-leaf part.

[0120] 7. When the value of the second proportion is less than or equal to the second preset proportion, the corresponding first boundary data belongs to the blade part; wherein the second preset proportion is greater than the first preset proportion; and the second preset distance is less than the first preset distance.

[0121] 8. When there is geometric point projection data within the third preset distance of the intersection point, the geometric point projection data is used to update the intersection point; the geometric point projection data is the point data after the geometric point of the rotating mechanical component to be distinguished is projected in the two-dimensional plane.

[0122] As a specific implementation, after executing step S6, the method further includes:

[0123] In addition, after executing step S6, the present invention includes:

[0124] The non-leaf part is retracted by a preset retraction distance along the direction inside the region where the projected point data is located. The intersection point is kept unchanged, and the expanded point data is added to the corresponding region of the leaf part to obtain the updated initial boundary data of the leaf part.

[0125] Specifically, the initial boundary data of the non-blade part of the rotating mechanical component to be distinguished in the boundary data of the area on the two-dimensional plane where the projection data of all the point data are located is retracted to the area on the two-dimensional plane where the projection data of all the point data are located, and the retracted initial boundary data of the non-blade part of the rotating mechanical component to be distinguished is obtained. Fig.13 As shown. And the position coordinates of the projected point data of the blade part where the blade part and the non-blade part meet and the projected point data of the non-blade part remain unchanged, and the expanded point data is added in the corresponding area of ​​the blade part to obtain the updated initial boundary data of the blade part. Fig.14 shown.

[0126] The intersection points of the blade part and the non-blade part remain unchanged, and the outward expansion data points are added in the blade area. The points in the non-blade area are retracted to the inside of the boundary line by a set length.

[0127] Specifically, the method of adding point data after expansion is:

[0128] Keep the intersection point of the blade part and the non-blade part unchanged, expand the first intersection point along the direction perpendicular to the Y axis by a preset distance to obtain the starting point after expansion; determine that three consecutive boundary points are the first boundary point (starting point), the second boundary point and the third boundary point respectively; the second boundary point and the first boundary point form a first vector, select the direction perpendicular to the first vector as the moving direction, expand the preset distance in the direction away from the area where the projected point data is located, and obtain the first boundary point after expansion and the first second boundary point after expansion; the second boundary point and the third boundary point form a second vector, select the direction perpendicular to the second vector as the moving direction, expand the preset distance in the direction away from the area where the projected point data is located, and obtain the second second boundary point after expansion and the third boundary point after expansion; the intersection of the straight line where the first boundary point after expansion and the first second boundary point after expansion are located and the straight line where the second second boundary point after expansion and the third boundary point after expansion are located is used as the point after the actual expansion of the second boundary point. Taking the second boundary point as the starting point, three consecutive boundary points are determined: the second boundary point, the third boundary point and the fourth boundary point, and the above steps are repeated until the boundary points of all blade parts are extended outward by a preset distance.

[0129] Optionally, the method for retracting by a preset distance is: first determine the boundary point on the y-axis, take the boundary point on the y-axis as the starting point, move the boundary point on the y-axis by a preset distance along the y-axis, and obtain the starting point after retraction; determine three consecutive boundary points as the first boundary point (starting point), the second boundary point and the third boundary point; the second boundary point and the first boundary point form a first vector, select the direction perpendicular to the first vector as the moving direction, and retract the preset distance in the direction of the area where the projected point data is located, to obtain the retracted first boundary point and the first retracted second boundary point; the second boundary point and the third boundary point form a second vector, select the direction perpendicular to the second vector as the moving direction, and retract the preset distance in the direction of the area where the projected point data is located, to obtain the retracted second second boundary point and the retracted third boundary point; the intersection of the straight line where the retracted first boundary point and the retracted first second boundary point are located and the straight line where the retracted second second boundary point and the retracted third boundary point are located is used as the point after the second boundary point is actually retracted. Taking the second boundary point as the starting point, three consecutive boundary points are determined: the second boundary point, the third boundary point and the fourth boundary point, and the above steps are repeated until all boundary points of the non-blade part are retracted by a preset distance.

[0130] Take the impeller as an example. Figure 8-Figure 16 As shown, the method for distinguishing the blade part and the non-blade part of the rotating machinery component provided by the present invention is further explained.

[0131] Step 1: Mesh the impeller's geometric data to obtain initial mesh data, and determine whether it needs to be encrypted based on the mesh side length or area. Encryption here also means increasing the density of the mesh.

[0132] Step 2: Identify the arcs in the impeller geometry data, and then determine the center of each arc based on the arc, and then obtain the position and direction of the rotation axis based on the position of the center and the normal of the arc. Figure 1 The position of the rotation axis of the rotating mechanical component shown. Specifically, the center of the circle on the rotation axis is the largest, that is, the number of the center of the circle on the same axis is the largest, and the direction of the normal of the axis is either the same direction or opposite, and the number of normals on the same axis that are either the same direction or opposite is the largest, then the axis is the rotation axis.

[0133] Step 3: Project the point data onto a two-dimensional plane according to the distance from the rotating axis to obtain the projected point data. In the present invention, the projected point data obtained in step 3 is used as the total data. Figure 2 The point data projected onto the two-dimensional plane is shown in FIG. In this step, all the point data of the impeller are simultaneously projected onto the same two-dimensional coordinate system.

[0134] Step 4: Rotate and translate the point data so that the axis coincides with the z-axis, and then divide the impeller point data into several parts according to the x and y coordinates of the impeller point data, for example, into 36 parts, and perform the above-mentioned projection operation on each part, that is, the projection operation in step 3, and project each part onto a two-dimensional plane to obtain multiple projected point data.

[0135] Step 5: Find the boundary lines for the total data and each part of the data on the two-dimensional plane. Fig. 9 , Fig.15 and Fig.16 shown.

[0136] Specifically, first determine the boundary point on the y-axis, take the boundary point on the y-axis as the starting point, and determine a vector in the direction perpendicular to the y-axis. Optionally, the vector can be a vector perpendicular to the y-axis. Then, preset a search range, and the starting point and the projected point data in the search range form a vector. The vector is called the target vector. The cross multiplication algorithm is applied to determine whether the projected point data in the search range is inside the unit vector or outside the unit vector (here it is assumed that a vector determined in the direction perpendicular to the y-axis is a boundary line, and it is determined whether the projected point data in the search range is inside or outside the boundary line).

[0137] First, search whether there is any projected point data within the range that is outside the unit vector. When the projected point data within the search range is outside the unit vector, select the projected point data within the search range that corresponds to the largest angle between the target vector and the unit vector as the point on the boundary line, and this point is called the adjacent boundary point.

[0138] When there is no projected point data within the range outside the unit vector, that is, when the projected point data within the search range are all within the unit vector, the projected point data within the search range corresponding to the smallest angle between the target vector and the unit vector is selected as the point on the boundary line, and this point is called a neighboring boundary point.

[0139] Then take the adjacent boundary point as the starting point and repeat the above steps.

[0140] Step 6: Compare the proportion of points on the total boundary line that exist within a certain distance in the partial data to determine whether the part is a leaf part. That is to say, when the proportion of the projected point data on the total boundary line that has corresponding projected point data on the boundary line of the partial data within a certain distance error reaches a preset proportion value, the projected point data on the total boundary line belongs to the non-blade part, and the projected point data on the boundary line of the partial data corresponding to the projected point data within a certain distance error also belongs to the non-blade part. In addition, the projected point data closest to the projected point data on the total boundary line is found on the boundary line of the partial data where there is no corresponding projected point data within a certain distance error, and it is considered that the projected point data on the boundary line of the partial data belongs to the blade part; on the contrary, if the projected point data on the total boundary line cannot find corresponding projected point data in the partial data within a certain distance error, then the projected point data on the total boundary line belongs to the blade part, and the projected point data on the boundary line of the partial data corresponding to the projected point data within a certain distance error also belongs to the blade part. In addition, the projected point data closest to the projected point data on the total boundary line is found on the boundary line of the partial data where there is no corresponding projected point data within a certain distance error, and it is considered that the projected point data belongs to the non-blade part on the boundary line of the partial data.

[0141] Step 7: For the connection between the blade part and the non-blade part, the point data can be encrypted to improve the proportion judgment condition in step 6, and then corrected according to the model geometry point information in step 2 to enable accurate distinction. Figure 5 The initial boundary line distinction between the blade part and the non-blade part of the rotating machine component is shown. Figure 5 The blades (red) are the blade part of the rotating machine component, and the non-blades (blue) are the non-blade part of the rotating machine component.

[0142] That is, the initial boundary data within the preset distance range where the initial boundary data of the blade part and the initial boundary data of the non-blade part meet is determined, and the initial boundary data within the preset distance range is used as the boundary data to be encrypted.

[0143] The boundary data to be encrypted is encrypted using a linear interpolation encryption method to obtain encrypted initial boundary data of the leaf portion and initial boundary data of the non-leaf portion.

[0144] Furthermore, encryption operations are performed on both the total boundary line and the partial data boundary line.

[0145] According to step 6, the leaf part and the non-leaf part of the encrypted data are determined, so as to obtain the initial boundary connection of the projected point data on the boundary line of the total data and the projected point data on the boundary line of each part of the data.

[0146] Finally, according to the model geometric point information in step 2, the coordinates of the projected point data corresponding to the blade part and the non-blade part at the initial boundary connection of the projected point data on the boundary line of the total data are corrected to obtain the coordinates of the projected point data at the connection of the blade part and the non-blade part on the boundary line of the corrected total data, thereby improving the accuracy of distinguishing between the blade part and the non-blade part, and further being able to obtain a high-precision working flow domain of the rotating machinery components.

[0147] In practical applications, after the above steps 1 to 6, the points on the total boundary line are distinguished as blade parts. A preset number of points are taken before and after each intersection of blades and non-blades. Similarly, the front and rear partial point data are taken at the place closest to the intersection of each partial boundary line, and the point data is linearly encrypted. Then the above-mentioned proportion judgment condition is improved to further distinguish the intersection point, that is, to determine whether the point data at the intersection point belongs to the non-blade part or the blade part. For the points in the original geometric model, the same projection is performed to obtain geometric projection two-dimensional points. The geometric points within a certain threshold from the dividing point will be used here to update the intersection point data, so as to further accurately distinguish. The above-mentioned increase in proportion to further distinguish is also to prevent errors caused by multiple adjacent geometric points here. Update the categories of the front and rear partial points according to this result.

[0148] Step 8: The non-leaf parts remain unchanged, and the leaf parts are expanded outward.

[0149] In practical applications, such as Fig.14 As shown, when the blade part is expanded, the boundary line of the non-blade part remains unchanged. After the blade part is expanded, the connection between the blade part and the non-blade part is the blade boundary.

[0150] Step 9 uses the resulting boundary line to rotate around the axis to generate a geometric entity, and then rotates and translates it to the original impeller position for subsequent division. The division of the present invention is to generate a segmentation surface. In addition, it can also be used for subsequent simulation calculations of CAE software. Figure 6 The results of distinguishing the bladed (red) and non-bladed (green) parts of a rotating machine component are shown.

[0151] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0152] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for distinguishing blade parts from non-blade parts of a rotating machine component, characterized in that: The method comprises: Acquire a CAD model of a rotating mechanical component to be distinguished and geometric information of the CAD model; Determining the rotation axis of the rotating mechanical component to be distinguished according to the geometric information; Meshing the rotating mechanical parts to be distinguished to obtain point data; According to the distance between the point data and the rotation axis and the distance between the point data and the plane where the position point of the rotation axis is located, the point data is projected onto a two-dimensional plane to obtain the projected point data; wherein the projected point data includes a group of projected data of all point data and multiple groups of projected data of partial point data; the plane where the position point of the rotation axis is located is perpendicular to the rotation axis; the acquisition process of the projected data of the multiple groups of partial point data specifically includes: taking the rotation axis as the intersection line, applying multiple intersection surfaces containing the intersection line to divide the point data of the rotating mechanical component to be distinguished into multiple parts; wherein the angles of adjacent intersection surfaces are consistent; projecting the point data of each part onto the two-dimensional plane respectively to obtain multiple groups of projected data of the partial point data; Obtaining a corresponding total boundary line and each partial boundary line according to the projected data of all the point data and the projected data of the partial point data projected on the two-dimensional plane; According to the correspondence between the total boundary line and each of the partial boundary lines, the blade part and the non-blade part of the total boundary line are distinguished to obtain the distinction result of the rotating mechanical parts to be distinguished, specifically including: Counting a first proportion of the projected point data in the total boundary line belonging to the partial boundary line within a first preset distance; When the value of the first proportion is greater than the first preset proportion value, the projected point data in the corresponding total boundary line belongs to the non-leaf part; When the value of the first proportion is less than or equal to the first preset proportion value, the projected point data in the corresponding total boundary line belongs to the blade part; According to the blade part, the non-blade part and the rotating shaft, a distinction result of the blade part and the non-blade part of the rotating mechanical component to be distinguished is obtained.

2. The method for distinguishing between blade parts and non-blade parts of a rotating machine component according to claim 1, characterized in that: Determining the rotation axis of the rotating mechanical component to be distinguished according to the geometric information specifically includes: According to the geometric information, a plurality of closed arcs included in the rotating mechanical component to be distinguished are identified and the center of each closed arc is determined; each closed arc is composed of a plurality of arcs connected end to end and the sum of the center angles of each arc is 360 degrees; The rotation axis of the rotating mechanical component to be distinguished is determined according to the center of the circle.

3. The method for distinguishing between the blade part and the non-blade part of a rotating machine component according to claim 2, characterized in that: Determining the rotation axis of the to-be-differentiated rotating mechanical component according to the center of the circle specifically includes: The number of the circle centers includes a plurality, and the directions of the vectors formed by the lines connecting the circle centers are determined to obtain a plurality of direction vectors; Counting the number of the direction vectors in each direction among the plurality of direction vectors; wherein the direction vectors with the same direction and the direction vectors with opposite directions are regarded as direction vectors in the same direction; The rotation axis of the rotating mechanical component to be distinguished is determined according to the direction corresponding to the direction vector with the largest number.

4. The method for distinguishing between blade parts and non-blade parts of a rotating machine component according to claim 1, characterized in that: Meshing the rotating mechanical parts to be distinguished to obtain point data specifically includes: Performing mesh division on the rotating mechanical parts to be distinguished to obtain an initial mesh; According to the density of the initial grid, determining whether to encrypt the initial grid; When the density of the initial grid is less than a preset threshold, each grid in the initial grid is meshed again to obtain a final grid; When the density of the initial grid is greater than or equal to the preset threshold, determining the initial grid as the final grid; Each vertex of the final mesh is determined as the point data.

5. The method for distinguishing blade parts from non-blade parts of a rotating machine component according to claim 1, characterized in that: After executing the step of "distinguishing the blade part and the non-blade part of the total boundary line according to the correspondence between the total boundary line and each of the partial boundary lines to obtain the differentiation result of the rotating machinery parts to be differentiated", the method further includes: The projected point data within a preset distance from each intersection point of the blade part and the non-blade part on the total boundary line is used as the boundary data to be encrypted; Applying a linear interpolation encryption method to encrypt the boundary data to be encrypted to obtain first boundary data; the first boundary data includes the encrypted initial boundary data of the leaf part and the initial boundary data of the non-leaf part; The projected point data of each of the partial boundary lines within a preset distance from the nearest projected point data of the intersection point is used as the data to be encrypted of each of the partial boundary lines; Encrypting the data to be encrypted of each of the partial boundary lines using a linear interpolation encryption method to obtain second boundary data of each of the partial boundary lines; Counting a second proportion of the first boundary data belonging to the second boundary data within a second preset distance; When the value of the second proportion is greater than the second preset proportion value, the corresponding first boundary data belongs to the non-leaf part; When the value of the second proportion is less than or equal to the second preset proportion, the corresponding first boundary data belongs to the blade part; wherein the second preset proportion is greater than the first preset proportion; and the second preset distance is less than the first preset distance; When there is geometric point projection data within the third preset distance of the intersection point, the geometric point projection data is applied to update the intersection point; the geometric point projection data is the point data after the geometric point of the rotating mechanical component to be distinguished is projected in the two-dimensional plane.

6. The method for distinguishing between blade parts and non-blade parts of a rotating machine component according to claim 5, characterized in that: After executing the step of "distinguishing the blade part and the non-blade part of the total boundary line according to the correspondence between the total boundary line and each of the partial boundary lines to obtain the differentiation result of the rotating machinery parts to be differentiated", the method further includes: The intersection point is kept unchanged, and the expanded point data is added in the corresponding area of ​​the leaf part to obtain the updated initial boundary data of the leaf part.

7. The method for distinguishing blade parts from non-blade parts of a rotating machine component according to claim 1, characterized in that: According to the blade part, the non-blade part and the rotating shaft, a distinction result between the blade part and the non-blade part of the rotating mechanical component to be distinguished is obtained, specifically including: Dividing the blade part and the non-blade part into a plurality of groups of boundary point data according to corresponding preset angle thresholds; Generate corresponding geometric edges according to each group of boundary point data; Determining a geometric surface according to the geometric edges of the blade portion and the geometric edges of the non-blade portion; The geometric surface rotates once with the rotation axis as the center to obtain the distinction result of the blade part and the non-blade part.

8. The method for distinguishing blade parts from non-blade parts of a rotating machine component according to claim 1, characterized in that: After executing the step of "distinguishing the blade part and the non-blade part of the total boundary line according to the correspondence between the total boundary line and each of the partial boundary lines to obtain the differentiation result of the rotating machinery parts to be differentiated", the method further includes: The non-leaf portion is retracted by a preset retraction distance along a direction inside the region where the projected point data is located.

Images