A turbine blade precision casting whole-process inverse deformation method based on a mesh node

Abstract

The application proposes a turbine blade precision casting whole process inverse deformation method based on grid nodes, divides the design model into multiple prt files, simultaneously imports HyperMesh, performs Boolean operation on the mutual contact bodies, divides the grid, then imports the casting special finite element software ProCAST to perform solidification stage simulation, then performs de-constraint stage simulation through extraction mapping operation, sets Vacant to ensure the consistency of the precision casting process grid nodes, replaces the solidification stage surface grid node P L (x, y, z) with the de-constraint stage deformed grid node P C (x, y, z) into the inverse deformation formula, and obtains the optimized mold cavity data through multiple inverse deformation iterations, which can effectively control the size change amount of the turbine blade in the precision casting process. Compared with the prior art, the application has the advantages that the turbine blade solidification stage and de-constraint stage, i.e. the turbine blade precision casting process, are considered simultaneously, the direct inverse deformation of the two stages of solidification + de-constraint is realized by ensuring the consistency of the nodes, so that the turbine blade size △D i meets the design requirements △D max , and the blade qualification rate is improved.

Description

Technical Field

[0001] This invention relates to the field of turbine blade size control methods, and in particular to a method for preventing deformation throughout the precision casting process of turbine blades based on mesh nodes. Background Technology

[0002] Aero-engines are the most advanced products in the equipment manufacturing field, representing a country's technological level and comprehensive national strength. Turbine blades are the core hot-end components that determine the performance, reliability, and safety of aero-engines, and leading aero-engine manufacturing countries maintain strict embargoes on their key technologies. Taking a certain type of hollow turbine blade as an example, even under conditions of dimensional accuracy concessions, the blade's dimensional deviation is still over 50%. To improve the turbine blade's yield rate, a mold with precise dimensions is first needed, which can, to a certain extent, control the turbine blade's shape. Manufacturing molds using the "trial and error method" is very expensive; therefore, it is necessary to use finite element software to analyze the dimensional changes of the turbine blade during the precision casting process.

[0003] Currently, most scholars consider the dimensional changes of turbine blades during the solidification stage, neglecting the impact of constraint removal on blade dimensions after solidification, such as the removal of constraints on the mold shell, process ribs, extension sections, and ceramic cores. Publicly available patents on constraint removal-based precision casting modeling and simulation methods (CN202210019676.X) and the paper "Simulation of Turbine Blade Precision Casting Core Removal Process and its Influence on Casting Stress / Dimensions" demonstrate that the stress release during constraint removal has a significant impact on the precision casting accuracy of turbine blades. Therefore, it is necessary to consider the entire precision casting process of turbine blades simultaneously, i.e., the solidification stage and the constraint removal stage, and determine the mold cavity dimensions through inverse deformation iteration to control the deformation of the turbine blade throughout the precision casting process, thereby improving the blade yield. Summary of the Invention

[0004] To control the deformation of turbine blades throughout the precision casting process and ensure that the blade dimensions meet design requirements, this invention proposes a mesh-based inverse deformation method for the entire precision casting process of turbine blades. Numerical simulation of the entire precision casting process is performed. While maintaining the unchanged mesh node numbers, the solidification and deconstraint stages are connected in series to achieve direct inverse deformation during the solidification and deconstraint stages. Through multiple iterations of the entire precision casting process, the dimensional changes of the turbine blades throughout the precision casting process are effectively controlled.

[0005] The technical solution of the present invention to achieve the above objectives includes the following steps:

[0006] Step 1:

[0007] The design model is divided and converted into a finite element model according to the actual factory process. The purpose is to lay the foundation for accurately simulating the constraint removal process. The method is as follows:

[0008] [1] Open the design model using the 3D software UG, and export multiple prt files for blades, extension sections, gating, cold copper and furnace body through splitting and merging operations;

[0009] [2] Import multiple prt files from [1] into HyperMesh, perform Boolean operations on the contacting bodies to make their contact surfaces share nodes, and then mesh each body using the hide command. Adjust the mesh size according to the different structures. After meshing is completed, export the out file.

[0010] [3] The out mesh file generated in [2] was imported into the casting-specific finite element software ProCAST through the Visual-Cast module. The furnace body was converted into a radiation region by the Convert to Enclosure command. The Visual-Mesh module was switched to repair the mesh, generate the shell and volume mesh, and then the gravity direction, material parameters, heat transfer coefficient and boundary condition parameters were set. Finally, the calculation was submitted to complete the simulation of the solidification stage of the precision casting process.

[0011] Step 2:

[0012] Based on the actual process, the solidified simulation casting completed in step 1 is subjected to a deconstraint operation, which is more consistent with the actual blade deconstraint process in production. The method is as follows:

[0013] [1] Copy the *vdb and *p.dat files generated in step 1 to a new folder. In order to achieve the anti-deformation in the solidification + unconstraint stage, it is necessary to ensure the consistency of the mesh nodes in the two stages. The constraint removal in actual production is simulated by setting Vacant.

[0014] [2] Establish new boundary conditions. Use the "four-point method" to constrain the blade's spatial position. Select Point1 on the blade and constrain its XYZ directions to 0. Select Point2 along the X direction of this point and constrain its Y direction to 0. Select Point3 along the Y direction of this point and constrain its Z direction to 0. Select Point4 along the Z direction of this point and constrain its X direction to 0.

[0015] [3] Submit the calculation to complete the simulation of the constraint removal stage of the precision casting process.

[0016] Step 3:

[0017] Step 1 completes the solidification stage simulation, and Step 2 completes the constraint removal stage simulation, realizing the simulation of the entire turbine blade precision casting process. Finally, the result files from Steps 1 and 2 are used for inverse deformation to obtain the mold cavity that meets the design requirements. The method is as follows:

[0018] [1] The inverse deformation iterative formula is: ,in These are the corresponding points for the mold cavity, the casting, and the theoretical model, respectively. k As a relaxation factor, k =1 indicates that the cavity can reach the theoretical model after the reverse deformation of the casting;

[0019] [2] Export the surface mesh file from the solidification stage of step 1, which contains the initial nodes of the model mesh. Coordinates, export the post-processed mesh file from step 2 (constraint removal stage). This file contains the mesh nodes of the model after deformation during the solidification and constraint removal stages. coordinate;

[0020] [3] Export from [2] and By substituting discrete point data into the inverse deformation iterative formula, an inverse deformation model is obtained. To verify the accuracy of this model, a full-process simulation of precision casting under the same technological conditions needs to be performed to determine the deformation at all discrete points. Is it smaller than the design requirements? , where i is the total number of discrete points.

[0021] Step 4:

[0022] If the discrete points after precision casting simulation of the anti-deformation model in step 3 are... If the simulation results do not meet the design requirements, steps 1, 2, and 3 need to be repeated under the same simulation parameters until the design requirements are met. , obtained This refers to the mold cavity data, which can effectively control the dimensional changes of turbine blades throughout the precision casting process.

[0023] The beneficial effects of this invention are: it simultaneously considers the dimensional changes of turbine blades during the solidification and deconstraint stages, which is more consistent with the actual blade casting process. To ensure the consistency of mesh nodes in both stages, Vacant is set to simulate constraint removal in actual production. The mold cavity size is determined by performing inverse deformation iteration on the three-dimensional mesh nodes, so that the discrete points after precision casting simulation under this mold are... This meets the design requirements, thereby effectively controlling the deformation of turbine blades throughout the precision casting process and improving the blade qualification rate. Attached Figure Description

[0024] Figure 1 This is a flowchart of a method for reversing deformation during the entire precision casting process of turbine blades based on mesh nodes, according to the present invention.

[0025] Figure 2 This is a finite element model diagram of a turbine blade precision casting according to one embodiment of the present invention;

[0026] Figure 3This is one embodiment of the present invention, which involves extracting the mapped temperature field map during the constraint removal stage.

[0027] Figure 4 This is a partial constraint model diagram of the constraint removal stage in one embodiment of the present invention;

[0028] Figure 5 This is a diagram of an anti-deformation optimization system for the entire process of precision casting of turbine blades according to one embodiment of the present invention;

[0029] Figure 6 This is a model diagram optimized by an anti-deformation system according to one embodiment of the present invention. Detailed Implementation

[0030] To more clearly illustrate the specific embodiments of the present invention, the invention will be described in detail with reference to the accompanying drawings and specific embodiments. However, the scope of protection of the present invention is not limited to the following embodiments. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can obtain other drawings based on the present invention without creative effort.

[0031] Taking a simplified aero-turbine turbine blade of a certain type as an example, the specific implementation process of this invention is as follows: Figure 1 As shown:

[0032] Step 1

[0033] The design model was divided and converted into a finite element model according to the actual factory process. The design model was then opened in the 3D software UG, and multiple .prt files were exported, including those for blades, extension sections, gating systems, cold copper, and the furnace body, through operations such as splitting and merging. These .prt files were then imported into HyperMesh. Boolean operations were performed on contacting volumes to ensure their contact surfaces shared nodes, such as blades and ceramic cores, gating systems and cold copper. Each volume was then meshed using the hide command, with the mesh size adjusted according to the structure. After meshing, all volumes were exported as .out files.

[0034] Figure 2 This is a finite element model diagram of a precision-cast turbine blade;

[0035] Step 2

[0036] To better reflect the actual process requirements, the solidification simulation of the casting completed in step 1 is deconstrained. The *vdb and *p.dat files generated in step 1 are copied to a new folder. The temperature and stress fields of the final step in the solidification stage are extracted and mapped. To achieve reverse deformation during the solidification and deconstraint stages, the consistency of mesh nodes in both stages must be ensured. This is achieved by setting Vacant to simulate constraint removal in actual production. New boundary conditions and operating parameters are established, and the calculation is submitted to complete the simulation of the deconstraint stage of the precision casting process.

[0037] Figure 3 The unconstraint stage extracts the mapped temperature field map;

[0038] Figure 4 This is a partial constraint model diagram from the constraint removal phase;

[0039] Step 3:

[0040] Step 1 completes the solidification stage simulation, and Step 2 completes the unconstraint stage simulation, realizing the simulation of the turbine blade precision casting process. Finally, the result files of Step 1 and Step 2 are used to perform reverse deformation to obtain the mold cavity that meets the design requirements. The surface mesh file of the solidification stage in Step 1 is exported. This file contains the initial node coordinates of the model mesh. The post-processed mesh file of the unconstraint stage in Step 2 is exported. This file contains the mesh node coordinates of the model after undergoing the solidification stage and the unconstraint stage deformation.

[0041] Figure 5 This is a diagram of the anti-deformation optimization system for the entire process of precision casting of turbine blades;

[0042] Step 4:

[0043] If the discrete points after precision casting simulation of the anti-deformation model in step 3 do not meet the design requirements, steps 1, 2 and 3 need to be repeated under the same simulation parameters until the design requirements are met.

[0044] Figure 6 It is a model diagram optimized using an anti-deformation system.

Claims

1. A method for reverse deformation throughout the precision casting process of turbine blades based on mesh nodes, characterized by the following steps: Step 1: The design model is divided and converted into a finite element model according to the actual factory process. The purpose is to lay the foundation for accurately simulating the constraint removal process. The method is as follows: [1] Open the design model using the 3D software UG, and export multiple prt files for blades, extension sections, gating, cold copper and furnace body through splitting and merging operations; [2] Import multiple prt files from [1] into HyperMesh, perform Boolean operations on the contacting bodies to make their contact surfaces share nodes, and then mesh each body using the hide command. Adjust the mesh size according to the different structures. After meshing is completed, export the out file. [3] Import the out mesh file generated in [2] into the casting-specific finite element software ProCAST through the Visual-Cast module, convert the furnace body into a radiation region through the Convert to Enclosure command, switch the Visual-Mesh module to repair the mesh, generate the shell shell and volume mesh, then set the gravity direction, material parameters, heat transfer coefficient and boundary condition parameters, and finally submit the calculation to complete the simulation of the solidification stage of the precision casting process. Step 2: Based on the actual process, the solidified simulation casting completed in step 1 is subjected to a deconstraint operation, which is more consistent with the actual blade deconstraint process in production. The method is as follows: [1] Copy the *vdb and *p.dat files generated in step 1 to a new folder. In order to achieve the anti-deformation in the solidification + unconstraint stage, it is necessary to ensure the consistency of the mesh nodes in the two stages. The constraint removal in actual production is simulated by setting Vacant. [2] Establish new boundary conditions and use the "four-point method" to constrain the blade's spatial position. Select Point 1 on the blade and constrain its XYZ directions to 0. Select Point 2 along the X direction of this point and constrain its Y direction to 0. Select Point 3 along the Y direction of this point and constrain its Z direction to 0. Select Point 4 along the Z direction of this point and constrain its X direction to 0. [3] Submit the calculation to complete the simulation of the constraint removal stage of the precision casting process; Step 3: Step 1 completes the solidification stage simulation, and Step 2 completes the constraint removal stage simulation, realizing the simulation of the turbine blade precision casting process. Finally, the result files from Steps 1 and 2 are used for inverse deformation to obtain the mold cavity that meets the design requirements. The method is as follows: [1] The inverse deformation iterative formula is: ,in These are the corresponding points for the mold cavity, the casting, and the theoretical model, respectively. k As a relaxation factor, k =1 indicates that the cavity can reach the theoretical model after the reverse deformation of the casting; [2] Export the surface mesh file from the solidification stage of step 1, which contains the initial nodes of the model mesh. Coordinates, export the post-processed mesh file from step 2 (constraint removal stage). This file contains the mesh nodes of the model after deformation during the solidification and constraint removal stages. coordinate; [3] Export from [2] and By substituting discrete point data into the inverse deformation iterative formula, an inverse deformation model is obtained. To verify the accuracy of this model, a precision casting process simulation under the same technological conditions needs to be performed to determine the deformation amount at all discrete points. Is it smaller than the design requirements? , where i is the total number of discrete points; Step 4: If the discrete points after precision casting simulation of the anti-deformation model in step 3 are... If the simulation results do not meet the design requirements, steps 1, 2, and 3 need to be repeated under the same simulation parameters until the design requirements are met. , obtained This refers to the mold cavity data, which can effectively control the dimensional changes of turbine blades during the precision casting process.

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