| Tungsten is considered to be the most potential Tokamak device facing plasma material.The performance of rolled tungsten plate is closer to the theoretical value and meets the needs of Tokamak device in extreme environment.The processing of rolled tungsten plate is one of the key technologies for the construction of large scientific device of magnetic confinement controlled nuclear fusion.A certain range of surface roughness can reduce the sputtering rate of tungsten and improve the operating parameters of the device.Adjusting the surface roughness of tungsten can improve the performance of Tokamak device.At the same time,in order to meet the needs of controlling the surface roughness of rolled tungsten plate,this paper puts forward a new idea of abrasive water jet machining rolled tungsten plate.The main research contents of this paper are as follows.Firstly,the application scope and basic principle of abrasive water jet are introduced,and the working principle and technical characteristics of pre mixed abrasive water jet and post mixed abrasive water jet are analyzed.This paper analyzes the flow beam structure,hydrodynamic characteristics and the mathematical basis of the calculation of main hydraulic parameters of abrasive water jet,and establishes the theoretical basis of abrasive water jet research.This paper analyzes the physical characteristics of tungsten such as high density and high melting point,and analyzes the difficult machining characteristics such as brittleness and strong affinity of rolled tungsten plate,and puts forward the potential advantages of abrasive water jet machining of rolled tungsten plate.This paper introduces the basic mathematical principle of SPH method and the theoretical basis of numerical simulation of SPH method coupled with FEM method,and analyzes the advantages of abrasive water jet cutting and rolling tungsten plate by Using SPH method coupled with FEM method.Using LS-DYNA software,the numerical simulation of abrasive water jet erosion of rolled tungsten plate based on SPH coupled FEM method is carried out,the particle motion characteristics in material erosion are analyzed,and the action mechanism hypothesis of abrasive water jet removal of tungsten material is put forward.This paper analyzes the action mechanism of abrasive water jet to remove plastic materials and brittle and hard materials,and provides a theoretical basis for the study of abrasive water jet to remove brittle and hard metal tungsten.Based on the 5-DOF pre mixed abrasive water jet cutting platform,the small batch test of abrasive water jet cutting rolled tungsten plate is designed and carried out.According to the value of section roughness,the range analysis of influencing factors is carried out,the influence law of cutting speed and jet pressure on section roughness is analyzed,and the key factors affecting section roughness are determined.The micro morphology of the section was obtained by scanning electron microscope,and the erosion traces such as brittle fracture and ploughing damage were analyzed to determine the action mechanism of abrasive water jet to remove the rolled tungsten plate.Based on the key factors affecting the section roughness,increase the types of experimental factors and improve the level of experimental factors,design and carry out the batch test of abrasive cutting and rolling tungsten plate to obtain more comprehensive sample data.Based on the samples of section roughness obtained from batch cutting test,a multivariate quadratic response surface regression model between cutting process parameters and section roughness is established by using linear regression method.Then,the BP artificial neural network prediction model of section roughness based on cutting process parameters is established by using artificial neural network method.After the comparison and experimental verification of the two models,it is found that the BP artificial neural network prediction model has high accuracy.In this paper,the numerical simulation and experiment of abrasive water jet erosion and cutting tungsten are carried out,the erosion simulation results and sample erosion traces are analyzed,the erosion mechanism of abrasive water jet removal of tungsten is revealed,the key factors affecting cutting efficiency and surface morphology are determined,the process parameter model of abrasive water jet cutting tungsten is established,and the surface roughness control method based on the process parameter model is constructed.Figure [20] Table [12] Reference [67]... |
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