Method and system for creating three-dimensional model of tail water flow channel

Abstract

The invention mainly relates to the field of hydropower engineering structure three-dimensional modeling. In order to improve the accuracy and automation degree of creation of a three-dimensional model of a tail water flow channel, the invention provides a method and system for creating a three-dimensional model of a tail water flow channel, and the core idea of the method is as follows: collecting parameters of the tail water flow channel, and converting the parameters into spatial position parameters and contour geometric parameters; the contour geometric parameters are converted into the established contour center coordinate system, and the contour type is judged according to the contour geometric parameters; generating a plurality of coupling points at different feature positions based on the contour type; generating an NURBS curve of each contour according to the contour shape geometric parameters in the contour center coordinate system; a coupling strategy is selected, coupling points on different contours are connected through an NURBS curve to generate ridge lines, and a ridge line set is established; and generating a tail water flow channel surface NURBS curved surface based on the contour NURBS curve and the generated ridge line, and then performing splicing to generate a tail water flow channel three-dimensional model.

Description

Technical Field

[0001] The present invention mainly relates to the field of three-dimensional modeling of hydropower engineering structures, and in particular to a method and system for creating a three-dimensional model of a tailwater flow channel. Background Art

[0002] The design of hydraulic structures plays a vital role in modern hydropower projects. The precise construction of tailwater channels is the key to ensuring the safety and function of the structures. In order to meet complex hydraulic conditions, tailwater channels often have extremely complex curved surfaces. Modern hydraulic design usually uses 3D modeling to accurately express their geometric shapes, which involves 3D modeling of tailwater channels. Traditional modeling methods usually require people to manually set multiple cross-sectional profiles according to manufacturer parameters, and then construct complex geometric shapes by stretching and lofting. Usually, a channel has 20 to 30 or even more standard cross-sections. Manually constructing these cross-sections is not only complicated and inefficient, but also often leads to errors in the middle due to human factors, resulting in rework and failure to meet the needs of rapid iterative design.

[0003] At present, some automated methods for tailrace flow channel modeling have been proposed, but these methods usually face many challenges. For example, tailrace flow channel modeling is based on grid modeling, but this method is difficult to effectively handle the flow channel morphology of complex surfaces, and has poor compatibility with mainstream design software, and does not have parameterization conditions, and cannot be modified after the model is established; some tailrace flow channel modeling methods have achieved automation to a certain extent, but still require manual intervention and adjustment, and cannot achieve fully automated modeling. Summary of the invention

[0004] Technical Problems to be Solved by the Invention

[0005] A method and system for creating a three-dimensional model of a tailrace flow channel are provided, aiming to improve the accuracy and automation of creating the three-dimensional model of the tailrace flow channel.

[0006] The technical solution adopted by the present invention to solve the above technical problems

[0007] In one aspect, the present invention provides a method for creating a three-dimensional model of a tailrace flow channel, comprising:

[0008] The method for creating a three-dimensional model of a tailwater flow channel includes:

[0009] Step S1: collecting tailwater flow channel parameters, and converting the collected tailwater flow channel parameters into a contour data set, wherein the contour data includes contour spatial position parameters and contour shape geometric parameters;

[0010] Step S2: converting the contour geometry parameters into the established contour center coordinate system according to the contour spatial position parameters;

[0011] Step S3: judging the contour type of each contour according to the contour shape geometric parameters in the contour center coordinate system;

[0012] Step S4: generating a plurality of coupling points at different feature positions based on the contour type;

[0013] Step S5: generating a NURBS curve set of each contour according to the contour shape geometric parameters in the contour center coordinate system;

[0014] Step S6: Select a coupling strategy and connect the coupling points on different contours using NURBS curves to generate ridge lines;

[0015] Step S7: Generate a NURBS surface of the tailrace flow channel surface based on the NURBS curve of the contour and the generated ridge line, and splice the generated NURBS surfaces to generate a three-dimensional model of the tailrace flow channel.

[0016] Furthermore, the spatial position parameters of the contour in step S1 include the coordinates (x, y, z) of the contour in the world coordinate system, and the contour shape geometric parameters include the rotation angles θ, β, γ of the plane where the contour is located around the x, y, and z axes, the width W of the contour, the height H of the contour, the chamfer radius R1 of the upper half of the contour, and the chamfer radius R2 of the lower half of the contour.

[0017] Furthermore, the outline types in step S3 include circle, single-sided semicircular rectangle, double-sided semicircular rectangle, single-sided semi-rounded rectangle, double-sided semi-rounded rectangle, single-sided rounded rectangle and double-sided rounded rectangle.

[0018] Furthermore, step S4 includes: selecting coupling points from feature points of the contour according to the types of the current contour and the subsequent contour; the feature points include the starting point and the end point of the arc, and the corner points of the rectangle.

[0019] Further, step S6 includes:

[0020] (1) Generate a contour type list CT according to the contour type judgment result in step S3, and record the number of each contour CT1, CT2, ..., CT in the contour type list. n ;

[0021] (2) Merge adjacent identical contours in the contour type list and record the number range [i, j] of each contour in each group of merged contours;

[0022] (3) Merge the adjacent identical contours in the contour type list CT to form the final contour type group CTC ((T k,[i,j]),…);T k is the contour type after fusion;

[0023] (4) Connect the contour type groups CTC ((T) according to the selected coupling strategy k ,[i,j]),…), form the ridge set L(L1,L2,…,L k ).

[0024] Further, step S7 includes:

[0025] (1) Obtain the contour NURBS curve set CS (CS1, CS2, ..., CS n ), ridge set L(L1,L2,…,L k ), merged contour type grouping CTC ((T k ,[i,j]),…);

[0026] (2) Group CTC by contour type ((T k ,[i,j]),…), and the contour number range [i,j] corresponding to the contour number range [i,j] in the NURBS surface lofting algorithm is called by the contour NURBS curve set CS (CS1,CS2,…,CS n ) in the NURBS curves and ridge sets L(L1,L2,…,L k ) to form the tailwater channel NURBS surface model NS(NS1,NS2,…,NS k );

[0027] (3) Perform surface splicing on the NURBS surface model to generate a three-dimensional model of the tailwater flow channel.

[0028] Furthermore, the generated tailwater flow channel 3D model is exported in STP format.

[0029] On the other hand, based on the above-mentioned tailrace flow channel three-dimensional model creation method, the present invention also provides a tailrace flow channel three-dimensional model creation system, including a data conversion module, a data preprocessing module, a cross-sectional contour recognition module, a coupling point generation module, a cross-sectional contour generation module, a model lofting generation module, and a model export module;

[0030] The data conversion module is used to collect tailwater flow channel parameters and convert the collected tailwater flow channel parameters into contour data set parameters; the contour data includes contour spatial position parameters and contour shape geometric parameters;

[0031] The data preprocessing module is used to convert the contour shape geometric parameters into the established contour center coordinate system according to the spatial position parameters of the contour in the contour data set;

[0032] The cross-section contour recognition module is used to determine the type of each contour according to the contour shape geometric parameters in the contour center coordinate system;

[0033] The coupling point generation module generates a plurality of coupling points at different feature positions based on the contour type;

[0034] The cross-section generation module generates a NURBS curve for each contour according to the contour shape geometric parameters in the contour center coordinate system, and establishes a NURBS curve set;

[0035] The model lofting generation module is used to connect corresponding coupling points on different cross-section contours using NURBS curves to generate a ridge set according to the selected coupling strategy; generate a NURBS surface on the tailwater flow channel surface based on the NURBS curve of the contour and the generated ridge, and splice the generated NURBS surface to generate a three-dimensional model of the tailwater flow channel;

[0036] The model export module is used to export the generated tailrace flow channel three-dimensional model according to a set export format.

[0037] Beneficial Effects of the Invention

[0038] The method and system for creating a three-dimensional model of a tailwater flow channel described in the present invention convert the original data of the tailwater flow channel into spatial position parameters and contour geometry parameters, and develop a program to pre-process the data; identify the contour data of each section to determine the contour type, perform secondary development and write a program to draw the contours of each section of the tailwater flow channel, add coupling points for different types of cross-sectional form combinations, realize multi-section lofting and obtain the final flow channel model; can realize the automatic generation of tailwater flow channels with complex curved surfaces, and greatly improve the modeling efficiency and reduce manual intervention while ensuring high precision, so as to meet the requirements of modern hydraulic structure design for efficient and accurate modeling of tailwater flow channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Create a flow chart for the tailrace 3D model;

[0040] Figure 2 NURBS curve generated in the embodiment;

[0041] Figure 3 It is the three-dimensional model of the tailwater flow channel generated in the embodiment. DETAILED DESCRIPTION

[0042] The tailwater runner three-dimensional model creation system of the present invention comprises a data conversion module, a data preprocessing module, a cross-section contour recognition module, a coupling point generation module, a cross-section contour generation module, a model lofting generation module, and a model export module; the tailwater runner three-dimensional model creation method of the present invention is as follows Figure 1 shown.

[0043] The data conversion module converts the tailwater flow channel parameters of the original manufacturer into the general profile data set parameters CP. The general profile data set parameters CP are composed of multiple profile data (CP1, CP2, CP3, ..., CP n ) is composed of each contour data CP i It consists of the spatial position parameters of the contour and the contour shape geometric parameters. The spatial position parameters include the position coordinates x, y, and z of the contour in the world coordinate system; the contour shape geometric parameters include the rotation angles θ, β, and γ of the plane where the contour is located around the x, y, and z axes, the width W of the contour, the height H of the contour, the chamfer radius R1 of the upper half of the contour, and the chamfer radius R2 of the lower half of the contour.

[0044] The data preprocessing module converts the parameter coordinate system S defined by the data set CP into w Transform to the established contour center coordinate system S c (Cartesian coordinate system), where the rotation transformation in the coordinate system transformation is calculated using quaternions. For any contour, its rotation around any axis The rotation quaternion q w for: Among them, α is the rotation angle of the contour around the axis. According to the rotation angle of the contour around the axis x, y, and z, the rotation quaternion q around the axis x, y, and z is calculated respectively. x ,q y ,q z , according to the rotation formula: in is the normal vector of the contour plane, is the z-axis vector (0,0,1), according to the contour plane normal vector and the input flow direction vector The third axis of the Cartesian coordinate system is obtained by vector cross multiplication A coordinate axis system is formed with the plane where the contour is located as the reference plane.

[0045] The cross-section contour recognition module is used to determine the contour type according to the contour shape geometric parameters in the contour center coordinate system.

[0046] The coupling point generation module is used to generate coupling points (S1, S2, ..., S j ), the coupling points are the feature points on the contour, and the feature points specifically include the start / end points of the arc segment and the corner points of the rectangle.

[0047] The cross-section generation module generates a NURBS curve for each contour according to the contour geometry parameters in the contour center coordinate system, and establishes a NURBS curve set CS (CS1, CS2, ..., CS n ).

[0048] The model lofting generation module stores coupling strategies for coupling points between different types of contours, which are used to select coupling strategies according to the contour type. The coupling strategies are specifically determined according to the geometric mapping relationship between the coupling points of the current contour and the subsequent contour. The corresponding coupling points on the contours of different sections are connected using NURBS curves to generate a ridge set, and a NURBS surface of the tailwater flow channel surface is generated based on the NURBS curve of the contour and the generated ridge line. The generated NURBS surfaces are spliced ​​to generate a three-dimensional model of the tailwater flow channel.

[0049] The model export module is used to export the generated tailrace flow channel three-dimensional model according to a set export format.

[0050] Furthermore, the method for generating ridge lines from coupling points is as follows:

[0051] (1) Generate a list of contour types based on the contour type recognition results of the cross-section contour recognition module, and record the number CT of each contour (CT1, CT2, ..., CT n );

[0052] (2) Merge adjacent identical contours in the contour type list and record the number range of the merged contours;

[0053] (3) The adjacent identical contours in the merged contours are merged again to form the final contour type grouping CTC ((T k ,[i,j]),…);T k is the contour type after fusion;

[0054] (4) Connect the contour type groups CTC ((T) according to the selected coupling strategy k ,[i,j]),…), form the ridge set L(L1,L2,…,L k ).

[0055] Furthermore, the method for generating the NURBS surface of the tailwater flow channel is as follows:

[0056] (1) Obtain the contour NURBS curve set CS (CS1, CS2, ..., CS n ), ridge set L(L1,L2,…,L k ), merged contour type grouping CTC ((T k ,[i,j]),…);

[0057] (2) Group CTC by contour type ((T k,[i,j]),…), and the contour number range [i,j] corresponding to the contour number range [i,j] in the NURBS surface lofting algorithm is called by the contour NURBS curve set CS (CS1,CS2,…,CS n ) in the NURBS curves and ridge sets L(L1,L2,…,L k ) to form the tailwater channel NURBS surface model NS(NS1,NS2,…,NS k );

[0058] (3) Perform surface splicing on the NURBS surface model to generate a three-dimensional model of the tailwater flow channel.

[0059] Example

[0060] This embodiment takes the modeling process of a tailwater flow channel of a power station as an example to further explain the modeling method and system for automatically creating a three-dimensional model of a tailwater flow channel described in the present invention.

[0061] Step 1. The manufacturer provides the single-line parameter table of the tailwater flow channel. The data conversion module converts the original data in the parameter table into a contour data set CP in the format of (θ, β, γ, x, y, z, W, H, R1, R2). The contour data set CP includes the spatial position parameters and contour shape geometric parameters of the contour, including the coordinates of the contour in the world coordinate system (x, y, z). The contour shape geometric parameters include the rotation angles θ, β, γ of the plane where the contour is located around the x, y, and z axes, the width W of the contour, the height H of the contour, the chamfer radius R1 of the upper half of the contour, and the chamfer radius R2 of the lower half of the contour.

[0062] Taking the contour CP3 in the tailwater flow channel data set of a power station as an example, the parameters in the contour data set are (0, 3.041, 0, 45.9, 0, -9750.4, 6580.4, 6420.4, 3210.2, 3210.2), where the angles are in radians and the other dimensions are in millimeters;

[0063] Step 2: The data preprocessing module converts the contour geometry parameters defined by the contour data set CP from the parameter coordinate system S w Transform to Cartesian coordinate system S c The rotation transformation in the coordinate system transformation is calculated using quaternions. For any contour, its rotation around any axis The rotation quaternion q w for: Among them, α is the rotation angle around the axis. According to the rotation angle of the contour around the axis x, y, and z, the rotation quaternion q around the axis x, y, and z is calculated respectively. x ,q y ,q z ,q x , according to the rotation formula: in is the normal vector of the contour plane, is the z-axis vector (0,0,1), according to the contour plane normal vector and the input flow direction vector The third axis of the Cartesian coordinate system is obtained by vector cross multiplication The coordinate axis system is formed with the plane where the contour is located as the reference plane. Taking contour CP3 as an example, after calculation, its normal vector The user input vector is

[0064] Step 3, the cross-section contour recognition module identifies the geometric features of the contour according to the contour shape geometric parameters (W, H, R1, R2), and divides the contour into 8 different types (T1, T2, T3, T4, T5, T6, T7, T8), including circle, single-sided semicircular rectangle, double-sided semicircular rectangle, single-sided semi-rounded rectangle, double-sided semi-rounded rectangle, single-sided rounded rectangle and double-sided rounded rectangle, among which the rounded rectangle is subdivided into 5 categories according to different chamfer positions and radii. In this embodiment, the CP3 contour is a circular contour;

[0065] Step 4: Coupling point generation module for each contour CP i Generate coupling points (S1, S2, ..., S j ), the coupling points are feature points on the contour, and the feature points include the start / end points of the arc segment and the corner points of the rectangle. According to the types of the current and subsequent contours, a specific set of points is selected from the feature points as the coupling points of the current contour. In this embodiment, the CP3 contour is divided into 1 / 4 circles to form 4 coupling points.

[0066] Step 5: The cross-section generation module generates the contour data CP i (i∈[1,n]) Generate the contour of NURBS 2D curves NS1, NS2, NS3,…, NS n ), the plane where the NURBS two-dimensional curve is located is the coordinate system reference plane calculated in step 2. The generated contour NURBS two-dimensional curve generated in this embodiment is as follows Figure 2 shown.

[0067] Step 6: According to the geometric mapping relationship of the contour coupling points in the selected coupling strategy, the coupling points on different contours are connected using NURBS curves to generate ridges, and a ridge set L (L1, L2, ..., L k ).

[0068] Step 7: Based on the generated contour NURBS curve, use the general lofting algorithm in 3D design to construct Figure 3 The three-dimensional model of the tailwater flow channel is shown in ND.

[0069] Step 8: Export the generated tailwater flow channel three-dimensional model ND in stp format.

Claims

1. A method for creating a three-dimensional model of a tailwater flow channel, characterized in that: include: Step S1: collecting tailwater flow channel parameters, and converting the collected tailwater flow channel parameters into a contour data set, wherein the contour data includes contour spatial position parameters and contour shape geometric parameters; Step S2: converting the contour geometry parameters into the established contour center coordinate system according to the contour spatial position parameters; Step S3: judging the contour type of each contour according to the contour shape geometric parameters in the contour center coordinate system; Step S4: generating a plurality of coupling points at different feature positions based on the contour type; Step S5: generating a NURBS curve set of each contour according to the contour shape geometric parameters in the contour center coordinate system; Step S6: Select a coupling strategy and connect the coupling points on different contours using NURBS curves to generate ridge lines; Step S7: Generate a NURBS surface of the tailrace flow channel surface based on the NURBS curve of the contour and the generated ridge line, and splice the generated NURBS surfaces to generate a three-dimensional model of the tailrace flow channel.

2. The method for creating a three-dimensional model of a tailwater flow channel according to claim 1, characterized in that: The spatial position parameters of the contour described in step S1 include the coordinates (x, y, z) of the contour in the world coordinate system, and the contour shape geometric parameters include the rotation angles θ, β, γ of the plane where the contour is located around the x, y, and z axes, the width W of the contour, the height H of the contour, the chamfer radius R1 of the upper half of the contour, and the chamfer radius R2 of the lower half of the contour.

3. The method for creating a three-dimensional model of a tailwater flow channel according to claim 1, characterized in that: The outline types in step S3 include circle, single-sided semicircular rectangle, double-sided semicircular rectangle, single-sided semi-rounded rectangle, double-sided semi-rounded rectangle, single-sided rounded rectangle and double-sided rounded rectangle.

4. The method for creating a three-dimensional model of a tailwater flow channel according to claim 1, characterized in that: Step S4 includes: selecting coupling points from the feature points of the contour according to the types of the current contour and the subsequent contour; the feature points include the starting point, the end point and the corner point of the arc.

5. The method for creating a three-dimensional model of a tailwater flow channel according to claim 4, characterized in that: Step S6 includes: (1) Generate a contour type list CT according to the contour type judgment result in step S3, and record the number of each contour CT1, CT2, ..., CT in the contour type list. n ; (2) Merge the adjacent identical contours in the contour type list CT, and record the number range [i, j] of each contour in each group of merged contours; (3) The adjacent identical contours in the merged contours are merged again to form the final contour type grouping CTC ((T k ,[i,j]),…);T k is the contour type after fusion; (4) Connect the contour type groups CTC ((T) according to the selected coupling strategy k ,[i,j]),…), form the ridge set L(L1,L2,…,L k ).

6. The method for creating a three-dimensional model of a tailwater flow channel according to claim 5, characterized in that: Step S7 includes: (1) Obtain the contour NURBS curve set CS (CS1, CS2, ..., CS n ), ridge set L(L1,L2,…,L k ), merged contour type grouping CTC ((T k ,[i,j]),…); (2) Group CTC by contour type ((T k ,[i,j]),…), and the contour number range [i,j] corresponding to the contour number range [i,j] in the NURBS surface lofting algorithm is called by the contour NURBS curve set CS (CS1,CS2,…,CS n ) in the NURBS curves and ridge sets L(L1,L2,…,L k ) to form the tailwater channel NURBS surface model NS(NS1,NS2,…,NS k ); (3) Perform surface splicing on the NURBS surface model to generate a three-dimensional model of the tailwater flow channel.

7. The method for creating a three-dimensional model of a tailwater flow channel according to claim 1, characterized in that: The generated tailwater channel 3D model is exported in STP format.

8. A system for creating a three-dimensional model of a tailrace flow channel, for implementing a method for creating a three-dimensional model of a tailrace flow channel as claimed in any one of claims 1 to 7, characterized in that: It includes data conversion module, data preprocessing module, cross-section profile recognition module, coupling point generation module, cross-section profile generation module, model lofting generation module, and model export module; The data conversion module is used to collect tailwater flow channel parameters and convert the collected tailwater flow channel parameters into contour data set parameters; the contour data includes contour spatial position parameters and contour shape geometric parameters; The data preprocessing module is used to convert the contour shape geometric parameters into the established contour center coordinate system according to the spatial position parameters of the contour in the contour data set; The cross-section contour recognition module is used to determine the type of each contour according to the contour shape geometric parameters in the contour center coordinate system; The coupling point generation module generates a plurality of coupling points at different feature positions based on the contour type; The cross-section generation module generates a NURBS curve for each contour according to the contour shape geometric parameters in the contour center coordinate system, and establishes a NURBS curve set; The model lofting generation module is used to connect corresponding coupling points on different cross-section contours using NURBS curves to generate a set of ridge lines according to the selected coupling strategy; generate a NURBS surface of the tailwater flow channel surface based on the NURBS curve of the contour and the generated ridge line, and splice the generated NURBS surface to generate a three-dimensional model of the tailwater flow channel; The model export module is used to export the generated tailrace flow channel three-dimensional model according to a set export format.

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