CN111950105B - Depth-first traversal-based three-dimensional model conversion method for thermal power plant pipeline - Google Patents

Abstract

The invention relates to the technical field of intersecting professions of computer software and a turbine pipeline, and discloses a thermal power plant pipeline three-dimensional model conversion method based on depth-first traversal, which realizes quick, accurate and stable conversion of a three-dimensional model between a CAD platform and a PDMS platform, and can generate an intermediate file format meeting CAESAR requirements, thereby facilitating CAESAR stress analysis and calculation. The method comprises the following steps: A. formulating an information format of the pipeline element; B. acquiring CAD three-dimensional model data of a pipeline and a pipe fitting thereof; C. generating an element object linked list according to the CAD three-dimensional model data, and setting an access identifier as False; D. generating a set with a pipeline topological connection relation for the elements in the element object linked list by using a depth-first traversal algorithm; E. generating an intermediate file according to the pipe systems of different branches in the set; F. and generating a thermal power plant pipeline PDMS three-dimensional model corresponding to the CAD three-dimensional model according to the intermediate file. The invention is suitable for conversion of the three-dimensional model of the thermal power plant pipeline between two platforms.

Description

Depth-first traversal-based three-dimensional model conversion method for thermal power plant pipeline

Technical Field

The invention relates to the technical field of intersecting professions of computer software and a turbine pipeline, in particular to a thermal power plant pipeline three-dimensional model conversion method based on depth-first traversal.

Background

Along with the increasing deepening of industrialization and informatization, the application of the digitizing technology in the industrial field is also gradually deepened, so that the digitizing technology is that the entity object in the traditional industrial field forms a digital twin corresponding to the entity object through ICT technologies such as computer technology (IT), communication Technology (CT), operation Technology (OT) and the like, and then the emerging technologies such as cloud computing, big data, internet of things, artificial intelligence and the like are utilized to improve the production efficiency and reduce the operation cost of enterprises. The application of digitization in the design of traditional thermal power plants is also spread for a long time, the modeling of the three-dimensional model of the thermal power plant pipeline is mainly finished on two large platforms of CAD and PDMS by each large power design institute at the present stage, and a series of corresponding secondary development work is finished on each platform aiming at the pipeline model, so that the three-dimensional pipeline model is designed to meet the requirements of the design specifications of the thermal power plant.

Generally, the three-dimensional model is converted on two platforms mainly by performing secondary development on a CAD model and generating a macro file meeting the PDMS creation model. The macro file generation mode creates equipment models with different specifications by reading macro commands row by row, the required data amount is not large, the method is not carried out by accessing engineering databases, the small-scale model is created at a high speed, no blocking occurs, but the blocking even causes program collapse when the large-scale model is processed, and the performance of computer hardware is affected. Moreover, the utilization rate of the intermediate macro file generated in the mode is not high, the intermediate macro file cannot be used as an intermediate file beneficial to pipeline stress analysis and calculation, is widely used for converting the three-dimensional model of equipment, and is not suitable for converting the three-dimensional model of the pipeline of a thermal power plant.

The other mode of generating the PDMS model by the CAD three-dimensional model is mainly applied to the major graphics, and is realized by expressing the digital elevation model by an irregular triangle network representation method. The irregular triangular network representation method utilizes discrete data obtained from all sampling points, connects the discrete points into triangular surfaces which are continuous with each other according to the principle of optimization combination, creates a three-dimensional model of a power plant on a CAD in the mode, and introduces the three-dimensional model data into the PDMS after secondary processing and organization according to a data format specific to the PDMS, thereby realizing the establishment of a three-dimensional factory model in the PDMS. The method provides a solution meeting the major of the total map, has a certain guiding significance for large-scale civil engineering digital engineering, but has insufficient scheme definition, and cannot convert and create the three-dimensional model of the thermal power plant pipeline, which is high in accuracy, high in creation speed and meets the arrangement requirement.

In recent years, international thermal power engineering is performed well, and in the pipeline stress analysis link of a thermal power plant, the results calculated by CAESAR software (pressure pipeline stress analysis professional software developed by COADE company in U.S. A.) are more important internationally.

In summary, the generation of the intermediate file format meeting the CAESAR requirement has a significant effect, on one hand, the conversion and creation of the three-dimensional model of the thermal power plant pipeline on the two platforms of CAD and PDMS can be realized, and on the other hand, the utilization rate of the generated intermediate file is high, and the CAESAR calculation can be met. Therefore, a three-dimensional model conversion method of the thermal power plant pipeline based on a depth-first traversal algorithm is provided, and conversion and rapid creation between two platforms are realized by creating an intermediate file (CII format file) through the depth-first traversal algorithm.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: the conversion method of the three-dimensional model of the thermal power plant pipeline based on depth-first traversal is provided, the three-dimensional model is quickly, accurately and stably converted between two platforms of CAD and PDMS, and an intermediate file format meeting CAESAR requirements can be generated, so that CAESAR stress analysis and calculation are facilitated.

The technical scheme adopted for solving the technical problems is as follows:

A thermal power plant pipeline three-dimensional model conversion method based on depth-first traversal comprises the following steps:

A. Formulating an information format of the pipeline element;

B. acquiring CAD three-dimensional model data of a pipeline and a pipe fitting thereof;

C. Generating an element object linked list according to the CAD three-dimensional model data, and setting an access identifier as False;

D. generating a set with a pipeline topological connection relation for the elements in the element object linked list by using a depth-first traversal algorithm;

E. generating an intermediate file according to the pipe systems of different branches in the set;

F. and generating a thermal power plant pipeline PDMS three-dimensional model corresponding to the CAD three-dimensional model according to the intermediate file.

As a further optimization, in the step a, the formulating the information format of the pipe element specifically includes:

By combing the Cii file format, the format of attribute information of pipeline elements which need to be filled in the model extension attribute XDATA in CAD three-dimensional modeling is formulated.

As a further optimization, in the step B, the acquiring CAD three-dimensional model data of the pipe and the pipe fitting thereof specifically includes:

and (3) identifying the three-dimensional model of the current CAD view, acquiring model entities of all pipelines and pipe fittings in the view, writing the extended attribute XDATA of all model entities into a text file in a data stream mode, and filtering useless XDATA.

In a further optimization step C, the generating an element object linked list according to the CAD three-dimensional model data specifically includes:

and reading and analyzing XDATA information in the text file row by row to generate an object linked list containing all elements of the three-dimensional model.

As a further optimization, in step D, the generating, by using a depth-first traversal algorithm, a set of element in the element object linked list, where the set has a pipeline topology connection relationship, specifically includes:

Performing depth-first traversal from an object closest to an origin coordinate in an element object chain, wherein the traversal process comprises the following steps:

(1) Setting the current element object access mark as True, sequentially reading the coordinates of the element objects in the linked list according to a cyclic structure, and judging whether the starting point, the ending point or the central point of the coordinates are equal to the starting point and the destination point of the current element;

(2) If the element objects are equal, the element objects are set as current element objects and jump out of the loop, the element objects are added into a list of temporary storage pipeline branches, and the element objects are deleted from a linked list of all the element objects; if not, placing the list into a set of storage tube systems, namely generating a branch of one tube system;

(3) Judging access marks of all element objects, and if the non-uniformity is True, setting a first element object in a linked list as a current element;

(4) Repeating the steps (1) - (3) until all elements in the linked list are accessed, and generating an element set for storing the piping.

In step E, generating an intermediate file according to the pipe systems of different branches in the set, which specifically includes:

Reading different branch information in an element set of a storage management system, and generating an intermediate file with suffix of Cii, wherein the suffix meets CAESAR calculation format, and the intermediate file comprises: control data unit, basic data unit, auxiliary data unit and other data units.

In step F, generating a PDMS three-dimensional model of the thermal power plant pipeline corresponding to the CAD three-dimensional model according to the intermediate file, which specifically includes:

F1. Reading a basic data unit starting point according to the intermediate file, and storing the basic data unit starting point into a unit node table;

F2. Merging node tables according to the endpoint-tee form, deleting repeated node numbers, processing the nodes of the tee according to the direction vector mode for branches connected with the same tee, judging that any two branch vectors are equal to each other as a main pipe section, and the other branch is a branch pipe section, thereby establishing each branch of a pipe system;

F3. and creating elements of each branch on the basis of the established branch, and completing conversion to the PDMS model.

The beneficial effects of the invention are as follows:

According to the method, the defects and limitations of conversion of the existing three-dimensional model from CAD to PDMS platform, reusability of intermediate files and other factors are considered, analysis creation of a three-dimensional model pipeline of a thermal power plant is completed by identifying and reading CAD model data and based on a depth-first traversal algorithm, the Cii intermediate files are generated, finally, the analysis intermediate files are read and created in the PDMS platform to create the pipeline, and the pipeline branches and the processing of elements such as elbows, tees and valves on the branches are created to generate a pipeline three-dimensional model, so that the conversion flow of the whole pipeline three-dimensional model of the thermal power plant is completed. The method has the advantages of high model precision, high conversion speed, stable conversion and the like, overcomes the difficult situations that the traditional two-platform modeling repeated work respectively and the traditional conversion mode do not meet the requirement of a pipeline three-dimensional model and the like, solves the problem of CAESAR stress analysis calculation of the pipeline three-dimensional model, and has important significance for model conversion data generation, international stress analysis requirement and the like in three-dimensional design.

Drawings

Fig. 1 is a flowchart of a thermal power plant pipeline three-dimensional model conversion method based on depth-first traversal in an embodiment.

Detailed Description

Aiming at the defects of the existing three-dimensional model conversion mode, the invention provides a thermal power plant pipeline three-dimensional model conversion method based on a depth-first traversal algorithm. The method constructs the Cii intermediate file recorded with the three-dimensional model information of the pipeline and the pipe fitting thereof through a computer program based on depth-first traversal, and the Cii intermediate file not only can complete the model conversion function of different platforms, but also can be used for CAESAR stress calculation and analysis.

In a specific implementation, the conversion method in the invention comprises the following steps:

A. And (3) format establishment: and (3) formulating information formats of pipe sections, elbows, big and small ends, tee joints and other pipe fittings of the pipeline according to CAESAR II Neutral File (neutral files) in a user application manual provided by CAESAR calculation software, so that the information formats can be conveniently generated in an extended attribute XDATA during CAD modeling.

B. And (3) data acquisition: and (3) identifying the three-dimensional model of the current CAD view, acquiring the model Entity (Entity) of all pipelines and pipe fittings in the view, writing the extended attribute XDATA of all Entity into a text file in a data stream mode, and filtering out useless XDATA.

C. Generating a topological relation: analyzing all XDATA information in the text file, generating a linked list containing all elements of the three-dimensional model, and generating a set with pipeline topological connection relation for unordered elements in the linked list through a depth-first traversal algorithm.

First, an Object linked list of all elements of the three-dimensional model is generated according to acad Id in XDATA in the CAD model, and an access mark Visit of each Object is set to False;

then, starting from the Object closest to the origin (0, 0) coordinate in the linked list, performing depth-first traversal, wherein the traversal algorithm is as follows:

(1) Setting the Object access mark Visit as True, adding the True into a temporary list, sequentially reading the coordinates of each Object in a linked list, and selecting a node associated with the current Object in a three-dimensional space;

(2) Judging whether the current node Object has an associated node or not, if not, adding a list into the set;

(3) Judging whether Object marks Visit of all elements in the linked list are True or not, if all nodes are accessed, finishing traversing, otherwise, setting a first element Object in the linked list as a current element;

(4) The above processes (1) - (3) are repeated until all the objects of the elements are accessed.

D. generating an intermediate file: and generating a pipe fitting information data pool according to the ordered pipe system sets of different branches in the set, and reading the data pool to generate an intermediate file with suffix of Cii meeting CAESAR calculation format.

E. creating a PDMS model: in a Design module of PDMS, opening a Cii file through a plug-in unit of secondary development, and analyzing each information module stored in the Cii file to generate a thermal power plant pipeline PDMS three-dimensional model corresponding to the CAD three-dimensional model, wherein the method specifically comprises the following steps:

(1) Reading a basic data unit starting point according to the intermediate Cii file, and storing the basic data unit starting point into a unit node table;

(2) Merging node tables according to the endpoint-tee form, deleting repeated node numbers, namely 2n+1 endpoint-tee branches (wherein n represents the number of tee joints of a pipe system), processing P1, P2 and P3 points of the tee joints according to the mode of directional vectors for branches connected with the same tee joint, and if any two vectors are equal, considering the branches as main pipe sections, namely P1-P2, and the other branch as a branch pipe section, namely P3, so as to establish each branch of the pipe system;

(3) And creating elements of each branch on the basis of the established branch to complete the conversion of the PDMS model.

Examples:

As shown in fig. 1, the method flow of converting the three-dimensional model of the thermal power plant pipeline based on the depth-first traversal algorithm in the embodiment includes the following implementation steps:

A. And (3) format establishment: through the aid of CAESAR software, translation reading of the document is facilitated, and Cii intermediate file formats conforming to stress analysis and calculation are carded out by means of a manual CAESAR II Neutral File edition. The Cii file is divided into four parts, namely a document control data recording unit, a basic data recording unit, an auxiliary data recording unit containing element data such as an elbow, a size head, a tee joint and the like, and other data recording units containing materials.

By combing the Cii file format, attribute information of different elements which need to be filled in the model extension attribute XDATA during CAD three-dimensional modeling is formulated, wherein the elements comprise: pipeline, elbow, big and small end, square and round joint, tee joint and socket, general rigid piece, valve, support and hanger logic point and end point thermal displacement. Specific processing is also performed on special elements such as three-way valves, angle valves and the like for different forms of each type of element, so that program identification is facilitated.

The standardization, institutional and standardized treatment of modeling personnel on creating the three-dimensional model is unified through the format establishment.

B. And (3) data acquisition: and obtaining model data by means of secondary development on the CAD platform. Specifically, based on the NET framework, the currently opened dwg graph is accessed according to a secondary development interface AutoCAD. Net API provided by AutoCAD. An Application object is the root object of the API interface through which the main window and any open graphics can be accessed. Once the graph is obtained, the Document object, database object, transaction object, and selection set object SelectionSet in the graph may be accessed, so that the Entity objects of all the elements of the three-dimensional model in the current view may be obtained, and thus, various data of the model may be obtained, where the data mainly includes: identification code, name, outside diameter wall thickness, temperature pressure, material, singleton, etc.

The data of each Entity Entity object is stored in a text file in a byte stream StringBuilder mode, the file at the moment can be regarded as a database file, and the String information of each line in the file is the specific description of a certain Entity Entity object in the dwg view. Since all entity objects in the acquired view have information that is not useful for generating the pipeline cii file, some useless line information needs to be deleted in the text file.

C. Generating a pipeline topological structure relation: and C, reading the text file row by row, and writing the information of different elements into a linked list which takes the Object base class as an element and corresponds to the program according to the XDATA format formulated in the step A, wherein the method mainly comprises the following steps: TUBI, elbow, tee, reduce, valve, atta, cap, PIPEENDPNT. And combining unordered elements in the linked list based on depth-first traversal to generate a tubing with the same connection topological relation as the CAD three-dimensional model.

C1. According to the identification acadId and other attribute information in each row of data, reading a first field of an attribute according to a program basic control structure executed according to the sequence, firstly judging PipeEndPoint, namely, end point thermal displacement and generating PIPEENDPNT types, continuously judging zdjljdsx, namely, a logic support and hanger and generating Atta types, finally judging that the first field is lbjsx, wherein a third field name comprises a Valve word and generates Valve types, a seal head or plug word and generates Cap types, a Tee word and generates Tee types, an elbow or an elbow pipe and generates Elbow types, a reducing pipe or a large-small head word and generates Reduce types, and a steel pipe or a round pipe and generates TUBI types. And setting an access flag Visit of each generated element Object as False and putting the False into a linked list until the last line of the text is read, and completing the mapping from the text to the Object.

C2. Starting from an object with the coordinate closest to the origin (0, 0) in a linked list formed by all element objects, traversing unordered element objects by using a depth-first traversing algorithm, and generating a management system with a topological logic relationship:

a) Setting the current element object access mark as True, sequentially reading the coordinates of the element objects in the linked list according to a cyclic structure, and judging whether the starting point end point or the central point of the coordinates is equal to the starting point end point of the current element;

b) If the element objects are equal, the element object is set as the current element object, the loop is jumped out, the element object is added into a list table of the temporary storage pipeline branch, and the element object is deleted from a linked list of all the element objects. If no equality is found, the temporary list table is placed into the collection of storage piping, i.e., a branch of one piping is generated.

C) And judging access marks Visit of all the element objects, if all the element objects are True, accessing all the element objects which generate branches, and collecting the elements to be the final pipeline. If not all True, continuing to set the first element object in the linked list as the current element;

d) Repeating the steps a) -c) until all elements in the linked list are accessed, namely the number of the element objects in the linked list is 0, and generating an element set for storing the piping.

D. generating an intermediate file Cii: and C, circularly reading each branch according to the set of the storage pipeline in the step C.

Generating a Cii file control data recording unit: and (3) reading each branch in the piping collection, and counting the total number NUMELT of piping elements, the number NOHGRS of spring support and hanging frames, the number NORED of big and small heads, the number BEND of elbows, the number RIGID of rigid parts, the number Restrant of constraint, the number Displacement of the end point thermal Displacement and the number Intersection of tee joints.

Generating a Cii file basic data recording unit: this unit involves data between some two element objects. The number of the initial and final nodes of the output unit is output, the pipeline number is 10 as an interval with the straight section and the bent pipe according to the pipeline flow direction, the number is started from 10000, and the position of the bent pipe node is the center point of the bent pipe; along the pipe flow direction, the free ends of the pipes are numbered from 501; the number of the tee joint element is numbered according to the existing glif, and the tee joint element is numbered from 301 along the pipeline flow direction; starting from the branch head of the pipeline, numbering the support and the hanger at intervals of 1 from 1; the rigid parts (flanges, valves and gaskets) are not node numbered; the accidental load points (concentrated loads) are numbered from 800 with 100 as interval; according to the coordinates between the elements, the projection distance of the output unit in the coordinate system XYZ, the outer diameter and the wall thickness of the output unit, the thickness of the insulation layer of the output unit, the operating temperature and the pressure under the output working condition, the density of the output insulation layer, the density of fluid in the output pipeline, the number of the end node elbow of the output unit (0 if not), the number of the end node rigid part of the output unit, the number of the end node constraint of the output unit, the number of the end node displacement load of the output unit, the number of the end node tee of the output unit and the number of the big end and the small end of the end node of the output unit are calculated.

Generating a Cii file auxiliary data recording unit: the auxiliary recording unit is divided into a bending unit, a rigid element, a constraint, a displacement load, a tee joint unit and a big head unit. Recording the radius of an elbow of the bending unit; recording the weight of the rigid unit rigid piece; recording the node number of the constraint (the node number is a corresponding element of a basic data recording part), the constraint type and the direction cosine of the constraint on XYZ; recording components Dx, dy and Dz of the displacement of the branch head or the branch tail of the displacement load; recording a tee joint number of the tee unit and an in-plane stress enhancement coefficient; the end outer diameter of the size head and the end wall thickness were recorded.

Generating other data record units of the Cii file: recording the corresponding ID of the material table, and correspondingly searching the material ID according to the material mapping relation between the material in Cii and the PDMS; recording a unit conversion constant and a unit converted by the unit; and recording the pipeline starting node number and node XYZ coordinates in coordinate checking.

E. Creating a PDMS model: and D, opening a Cii file and analyzing each unit data into a program data pool through an independently developed plug-in the PDMS design platform, and completing the reverse process opposite to the CII file according to the step D to generate a thermal power plant pipeline three-dimensional model with the PDMS identical to the CAD three-dimensional model in logical structure and data attribute.

E1. Because the CAESAR calculation software outputs the corresponding pipeline three-dimensional model according to the Cii file format (namely, the Cii file after stress calculation is completed through CAESAR is not identical to the file generated in the step D, but the expressed pipeline model is identical), in order to make the mode of importing the model have greater applicability, the model is put into the unit node table by reading the unit origin-destination node number of the basic data unit of the Cii file.

E2. Combining node tables according to the endpoint-tee form, deleting repeated node numbers, namely 2n+1 endpoint-tee small branches (wherein n represents the number of tee joints of a pipe system), particularly in the aspect of processing tee joints, processing P1, P2 and P3 points of different small branches connected with the same tee joint according to the mode of directional vectors, wherein any two vectors are equal and considered as a main pipe section, namely P1-P2, and the other branch is a branch pipe section, namely P3, and establishing each branch of the pipe system according to the mode;

E3. A Zone and the following Pipe level are created on PDMS, automatically populated with DBelement names, pipe levels. And generating all the elements below each branch, finding out the class of the element library according to the outer diameter and the wall thickness of the element, and finding out the attribute of the class library according to the temperature and the pressure intensity of the element, thereby creating a pipeline model according to the class library of the element library and the data information of different attributes of different elements.

Claims (6)

1. A conversion method of a three-dimensional model of a thermal power plant pipeline based on depth-first traversal is characterized by comprising the following steps:

A. Formulating an information format of the pipeline element;

B. acquiring CAD three-dimensional model data of a pipeline and a pipe fitting thereof;

C. Generating an element object linked list according to the CAD three-dimensional model data, and setting an access identifier as False;

D. generating a set with a pipeline topological connection relation for the elements in the element object linked list by using a depth-first traversal algorithm;

E. generating an intermediate file according to the pipe systems of different branches in the set;

F. generating a thermal power plant pipeline PDMS three-dimensional model corresponding to the CAD three-dimensional model according to the intermediate file;

in step D, the generating, by using a depth-first traversal algorithm, a set of element object links with a pipeline topology connection relationship, specifically includes:

Performing depth-first traversal from an object closest to an origin coordinate in an element object chain, wherein the traversal process comprises the following steps:

(1) Setting the current element object access mark as True, sequentially reading the coordinates of the element objects in the linked list according to a cyclic structure, and judging whether the starting point, the ending point or the central point of the coordinates are equal to the starting point and the destination point of the current element;

(2) If the element objects are equal, the element objects are set as current element objects and jump out of the loop, the element objects are added into a list of temporary storage pipeline branches, and the element objects are deleted from a linked list of all the element objects; if not, placing the list into a set of storage tube systems, namely generating a branch of one tube system;

(3) Judging access marks of all element objects, and if the non-uniformity is True, setting a first element object in a linked list as a current element;

(4) Repeating the steps (1) - (3) until all elements in the linked list are accessed, and generating an element set for storing the piping.

2. The method for converting a three-dimensional model of a thermal power plant pipeline based on depth-first traversal according to claim 1, wherein in the step a, the information format of the pipeline element is formulated, specifically comprising:

By combing the Cii file format, the format of attribute information of pipeline elements which need to be filled in the model extension attribute XDATA in CAD three-dimensional modeling is formulated.

3. The method for converting a three-dimensional model of a thermal power plant pipeline based on depth-first traversal according to claim 2, wherein in the step B, the obtaining CAD three-dimensional model data of the pipeline and the pipe fitting thereof specifically comprises:

And (3) identifying the three-dimensional model of the current CAD view, acquiring model entities of all pipelines and pipe fittings in the view, writing the extended attribute XDATA of all model entities into a text file in a data stream mode, and filtering useless XDATA.

4. The method for converting a three-dimensional model of a thermal power plant pipeline based on depth-first traversal as claimed in claim 3, wherein in the step C, the generating element object linked list according to the CAD three-dimensional model data specifically comprises:

and reading and analyzing XDATA information in the text file row by row to generate an object linked list containing all elements of the three-dimensional model.

5. The method for converting a three-dimensional model of a thermal power plant pipeline based on depth-first traversal according to claim 1, wherein in the step E, the generating an intermediate file according to the pipe systems of different branches in the set specifically comprises:

reading different branch information in an element set of a storage management system, and generating an intermediate file with suffix of Cii, wherein the suffix meets CAESAR calculation format, and the intermediate file comprises: control data unit, basic data unit, auxiliary data unit and other data units.

6. The method for converting a three-dimensional model of a thermal power plant pipeline based on depth-first traversal according to any one of claims 1-5, wherein in step F, the generating a PDMS three-dimensional model of the thermal power plant pipeline corresponding to the CAD three-dimensional model according to the intermediate file specifically comprises:

F1. Reading a basic data unit starting point according to the intermediate file, and storing the basic data unit starting point into a unit node table;

F2. Merging node tables according to the endpoint-tee form, deleting repeated node numbers, processing the nodes of the tee according to the direction vector mode for branches connected with the same tee, judging that any two branch vectors are equal to each other as a main pipe section, and the other branch is a branch pipe section, thereby establishing each branch of a pipe system;

F3. and creating elements of each branch on the basis of the established branch, and completing conversion to the PDMS model.