Turbine transient stress field simulation finite element result singular point correction method, electronic equipment and computer readable storage medium
By correcting singularities in the transient stress field simulation of steam turbines using the K-nearest neighbor algorithm and the inverse distance weighting method, the problem of singularities affecting simulation results is solved, stress field data is smoothed and completed, analysis accuracy is improved and computational resources are saved.
Patent Information
- Application Number
- CN202510770960.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-10
- Publication Date
- 2025-10-17
AI Technical Summary
In the transient stress field simulation of steam turbines, the existence of singularities leads to inaccurate simulation results, affecting life prediction and digital twin analysis, and recalculation consumes a lot of computing power.
The K-nearest neighbor algorithm and inverse distance weighted method are used to correct singular points. By establishing a finite element model, singular points are screened out and the weights of adjacent nodes are calculated. The stress values of the singular points are corrected using interpolation calculation to ensure the continuity and stability of the stress field data.
It effectively eliminates the influence of singularities, improves the accuracy of simulation results, saves computing resources, and ensures the accuracy of digital twin analysis and lifetime prediction.
Smart Images
Figure CN120805545A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of steam turbine stress calculation, and in particular to a steam turbine transient stress field simulation finite element result singular point correction method, an electronic device and a computer readable storage medium. BACKGROUND
[0002] The main reasons for generating singular points in the finite element calculation process are constraint problems, mesh problems and structure problems. When the above unreasonable conditions occur, the result is that there are singular points in the result, and the numerical value near a certain point is too large, exceeding the position that should be analyzed. In the steady-state simulation of a steam turbine, the singular points of the main components (rotor, valve and cylinder) of the steam turbine are often ignored. Usually, the singular reasons are found, and after the reasons are found, the model is recalculated or the singular points are not processed, and other points are ignored. However, in recent years, with the application of digital twinning in key components of steam turbines, heavy reliance is placed on the transient simulation field of the steam turbine. By changing the input parameters, the full-field finite element simulation results of different working conditions are obtained. As an important data support source for digital twinning, the full-field data at different time layers cannot be directly ignored, and re-computing will waste a lot of computing power, and ignoring the singular points will result in incomplete elements, affecting the overall display, and the large singular point value can easily cover the main characteristics, especially for the stress field, the large stress value will directly affect the calculation result of the service life. SUMMARY
[0003] Therefore, the present application provides a steam turbine transient stress field simulation finite element result singular point correction method, an electronic device and a computer readable storage medium, which can correct the stress value of the singular point, so that the numerical value of the singular point is smoothed and completed.
[0004] To solve the above technical problems, the technical scheme adopted by the present application is as follows: A steam turbine transient stress field simulation finite element result singular point correction method, the singular point correction method comprising the following steps: S1, establishing a finite element model and obtaining nodes: establishing a finite element model of a simulation element of a steam turbine, performing mesh division on the finite element model and obtaining n nodes, the nodes being represented as , wherein is a node number, and are coordinate values of the nodes; the stress value of the node is represented as , wherein is a time layer number, and the time layer has S2, obtaining singular points: setting a stress threshold of singular points, determining stress values of each node at the last steady state time of the start-up process of the simulation element of the steam turbine through the simulation of the steam turbine by the finite element model , screening out nodes with stress values greater than the stress threshold of singular points as singular points, and the singular points are represented as , , wherein is a singular point number, and the stress value of the singular point is represented as ; S3, obtaining adjacent nodes around the singular points: obtaining distances of each node to the singular points , and the distance calculation formula is: , from all nodes n, select nodes closest to the singular points and record the node numbers, form a new sequence for each singular point, delete the singular points in the new sequence, and obtain an adjacent node data set, and the adjacent nodes are represented as , ; S4, calculating the weight of the adjacent nodes on the singular points: the distance function between the adjacent nodes and the singular points is: ; the weight of the adjacent nodes on the singular points is calculated , and the calculation formula is: , wherein p is a weight factor; S5, correcting the stress value of the singular points: according to the inverse distance weighting method, the stress values of each singular point in the time layer during the transient start-stop process of the simulation element of the steam turbine are calculated by interpolation, and the corrected stress values of the singular points are obtained , and the calculation formula is: , wherein is a stress value of the adjacent nodes; S6, the corrected stress values of the singular points are applied to the calculation of each time layer, ensuring that the stress field data at each time is effectively processed, and ensuring the continuity and stability of the transient stress field data.
[0005] Further, the simulation element of the steam turbine in S1 is a rotor, a valve or a cylinder of the steam turbine.
[0006] Further, the stress threshold of the singular point in S2 is the maximum value of the Mises stress .
[0007] Further, the is selected in the range of 550-600Mpa.
[0008] Further, the in S3 is in the range of 40-60.
[0009] Further, the p in S4 is 2 or 3.
[0010] Another technical solution adopted by the present application is: An electronic device, comprising a memory and a processor, the memory stores a computer program, and the processor implements the steps of the singular point correction method of the transient stress field simulation finite element result of a steam turbine when executing the computer program.
[0011] Another technical solution adopted by the present application is: A computer readable storage medium having a computer program stored thereon, the computer program is executed by a processor to implement a singular point correction method of a transient stress field simulation finite element result of a steam turbine.
[0012] Compared with the prior art, the present application has the following beneficial effects: By using the K-nearest neighbor algorithm and the inverse distance weighting method to correct the singular points, the present application can effectively eliminate the singular points caused by unreasonable grid, constraint or structure in finite element simulation. Avoid the large numerical value of the singular point to cover the change of the real stress field, so as to affect the accuracy of the entire simulation result. After the singular point is corrected, the numerical value of the singular point is smoothed and completed, so that the rotor, valve and cylinder steady-state transient stress field data of the steam turbine have a complete data, and the reconstructed singular point does not abnormally stand out in the value and the value nearby. Using the reconstructed value for subsequent digital twin analysis will not be too large. It can more accurately represent the unique properties of the steam turbine components and complete the life prediction work. BRIEF DESCRIPTION OF DRAWINGS
[0013] The accompanying drawings are part of the present application and serve to provide a further understanding of the present application.
[0014] Figure 1 The flowchart of a singular point correction method of a transient stress field simulation finite element result of a steam turbine of the present application.
[0015] Figure 2 The stress field diagram when there is a singular point in a certain time layer of the cylinder.
[0016] Figure 3 The stress field diagram after correcting the singular point for a certain layer of the cylinder. DETAILED DESCRIPTION
[0017] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.
[0018] Figure 1 The flowchart of the singular point correction method of the finite element simulation results of the transient stress field of a steam turbine according to this embodiment is shown. Since the stress fields of the steam turbine's rotor, valves, cylinders and other components are relatively intense, singular points are more likely to be generated during steady-state simulation. Steady-state refers to the steam turbine operating under 100% working conditions. Therefore, this embodiment mainly corrects the singular points generated by these three components during steady-state simulation. The rotor, valves and cylinders are hereinafter referred to as simulation elements. Figure 1 As shown in FIG, the correction method of the singular point includes the following steps: S1, establish finite element model and obtain nodes: import the CAD model of the steam turbine simulation component and establish a finite element model to perform steady-state simulation on the steam turbine simulation component. Mesh the finite element model and obtain n nodes, which are represented by , ,in is the node number, are the coordinate values of the nodes. The stress value of the node is expressed as , ,in is the time layer number, the time layer has layer.
[0019] S2, obtain the singular point: set the stress threshold of the singular point, perform transient start and stop of the simulation components of the steam turbine through the finite element model, and determine the stress value of each node at the last steady-state moment of the startup process , select the nodes with a stress greater than the singular point threshold as the singular point. The stress threshold of the singular point can be the maximum value of the Mises stress , The selection range is 550-600Mpa. The screening method can be done by model screening or by manually viewing the stress field diagram. The singular point is represented by , ,in is the singular point number, and the stress value of the singular point is expressed as .
[0020] S3, obtain the adjacent nodes around the singular point: use the K nearest neighbor algorithm to obtain the nodes around the singular point as the reconstruction data source. Specifically, obtain the distance between each node and the singular point , the distance calculation formula is: , Select from all nodes n distance singularity The nearest node and record the node number, where The value range is 40-60. A new set of sequences is formed for each node selected from a singular point. Since the nodes adjacent to the singular point may also have singular points, the singular points that appear in the new sequence are deleted and the adjacent node data set is obtained. The adjacent nodes are represented as , There are a total of singular points, so there are Group neighboring node dataset.
[0021] S4, calculate the weight of the adjacent nodes to the singular point: the closer the adjacent nodes are to the singular point, the greater the influence on the stress value of the singular point, and the greater the weight. The inverse distance weighted algorithm is used to calculate the weight of the adjacent nodes to the singular point. and singularities The distance function between for: ; Calculate the weight of the neighboring nodes to the singular point , and its calculation formula is: in, p is the weight factor, which is usually 2 or 3.
[0022] S5, correct the stress value of the singular point: According to the inverse distance weighted method, the stress value of each singular point in the time layer of the simulation component of the steam turbine during the transient start and stop process is interpolated using the adjacent nodes to obtain the corrected stress value of the singular point , the calculation formula is: in, is the stress value of the adjacent node.
[0023] S6, the corrected singular point stress value is applied to the calculation of each time layer to ensure that the stress field data at each moment is effectively processed and the continuity and stability of the transient stress field data are guaranteed.
[0024] It has been verified that the effect of an uncorrected singular point at a certain time layer is as follows Figure 2 As shown in the figure, the amplitude reaches 1140Mpa, which is much higher than the yield limit of the material. The corrected effect is shown in the figure below. Figure 3 As shown in the figure, the stress amplitude near the singular point drops below 550 MPa, and the stress distribution is relatively smooth.
[0025] It can be seen that, by using the K-nearest neighbor algorithm and inverse distance weighting method to correct singular points, the singular points caused by unreasonable grid, constraint or structure in finite element simulation can be effectively eliminated. The numerical value of the singular point is smoothed and completed after correction, avoiding the interference of the excessive stress value on subsequent analysis, and being able to more accurately represent the unique properties of the steam turbine components and complete the life prediction work. In addition, by correcting the singular points through the algorithm, the re-computation is avoided, and the waste of computing resources is reduced. Especially in complex transient simulation, by smoothing and correcting the singular points, the calculation time and computing resources can be significantly saved while maintaining the accuracy of the results. Overall, the singular point problem in the transient stress field simulation of the steam turbine is effectively eliminated by the post-processing correction method, avoiding the negative impact of inaccurate data on digital twin analysis and life prediction. The method can achieve significant results in improving analysis accuracy, saving computing resources, enhancing data continuity, and providing more reliable data support for the optimization design and maintenance of steam turbines and other mechanical equipment.
[0026] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.
Claims
1. A method for correcting singular points in finite element results of transient stress field simulation of a steam turbine, characterized in that: The correction method of the singular point includes the following steps: S1, establish finite element model and obtain nodes: establish finite element model of simulation components of steam turbine, mesh the finite element model and obtain n nodes, the nodes are represented as , ,in is the node number, are the coordinate values of the nodes respectively; the stress values of the nodes are expressed as , ,in is the time layer number, the time layer has layer; S2, obtain the singular point: set the stress threshold of the singular point, perform transient start and stop of the simulation components of the steam turbine through the finite element model, and determine the stress value of each node at the last steady-state moment of the startup process , select the nodes with stress greater than the singular point threshold as the singular point, and the singular point is expressed as , ,in is the singular point number, and the stress value of the singular point is expressed as ; S3, obtain the adjacent nodes around the singular point: obtain the distance between each node and the singular point , the distance calculation formula is: , Select from all nodes n distance singularity The nearest node and record the node number, form a new set of sequences for the nodes selected from each singular point, delete the singular points that appear in the new sequence, and obtain the adjacent node data set. The adjacent nodes are represented as , ; S4, calculate the weight of the adjacent nodes to the singular point: the adjacent nodes and singularities The distance function between for: ； Calculate the weight of the neighboring nodes to the singular point , and its calculation formula is: in, p is the weight factor; S5, correct the stress value of the singular point: According to the inverse distance weighted method, the stress value of each singular point in the time layer of the simulation component of the steam turbine during the transient start and stop process is interpolated using the adjacent nodes to obtain the corrected stress value of the singular point , the calculation formula is: in, is the stress value of the adjacent node; S6, the corrected singular point stress value is applied to the calculation of each time layer to ensure that the stress field data at each moment is effectively processed and the continuity and stability of the transient stress field data are guaranteed.
2. The method for correcting singular points in finite element results of transient stress field simulation of a steam turbine according to claim 1, characterized in that: The simulation elements of the steam turbine in S1 are the rotor, valve or cylinder of the steam turbine.
3. The method for correcting singular points in finite element results of transient stress field simulation of a steam turbine according to claim 1, characterized in that: The stress threshold of the singular point in S2 is the maximum value of the Mises stress .
4. The method for correcting singular points in finite element results of transient stress field simulation of a steam turbine according to claim 3, characterized in that: described The selection range is 550-600Mpa.
5. The method for correcting singular points in finite element results of transient stress field simulation of a steam turbine according to claim 1, characterized in that: The S3 The value range is 40-60.
6. The method for correcting singular points in finite element results of transient stress field simulation of a steam turbine according to claim 1, characterized in that: The S4 p The value of is 2 or 3.
7. An electronic device, characterized in that The invention comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method for correcting singular points of finite element results of transient stress field simulation of a steam turbine according to any one of claims 1 to 6 is implemented.
8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for correcting singular points in finite element results of a steam turbine transient stress field simulation as described in any one of claims 1 to 6 is implemented.