Numerical Simulation Of D.C. Arc Plasma Torch And The Physical Study Of Electron Beam Ion Trap

This thesis is composed of two parts.As an efficient and clean heat source, D. C. arc plasma torches have been widely used in many of industrial applications, such as cutting, welding, plasma spraying, waste destruction, materials processing, and aeronautics etc.. A better understanding of the physical processes occurring inside the plasma torches can greatly help us design and optimize these devices which are suitable for different purpose. In the first part of this thesis, the physical processes occurring inside the plasma torches are discussed in detail at first. Then the magnetohydrodynamic ( MHD ) model of a plasma torch, and the method for the numerical simulation used in this paper are discussed in detail also. By means of numerical simulation, D. C. arc plasma torches of SG-100 series which are the commercial products of PRAXAIR company, and the plasma jet are systematically studied. The two- and three- dimensional plasma flows inside the torches, the plasma flows inside the torches with different nozzle configurations, the laminar and turbulent plasma flow regimes, different plasma ambient gas, and subsonic to supersonic flows are studied in detail. This simulation studies covered a wide range of plasma parameters, which encountered in the scientific researches and industrial applications. In the three-dimensional modeling of plasma torch, we bring forward the physical model which is based on the model of D. A. Scott. Using this model, we successfully got the convergent results, and the modeling results are consistent with the experimental data. Aditionally, the parameter studies are performed, and the results show the increasing of plasma current and inflow gas rates play different role in affecting the plasma parameters such as temperature and velocity. Comparison between the plasma flows inside torches with different nozzle configurations are made also, the results show the plasma torches with different nozzle configurations can produce differentcharacteristic plasma jet. And the turbulent effect inside the plasma torches seems have something to do with the nozzle dimension near the cathode tip, the bigger the nozzle dimension near the cathode tip, the larger the turbulent effects.Electron Beam Ion Trap ( EBIT) uses highly compressed electron beam to ionize ions and atoms to produces highly charged ions. lonization stages of almost any element in the Periodic Table can be produced and trapped for several hours in the EBIT. In the second part of this thesis, the physical model, which used to describe the evolution of highly charged ions in the EBIT and provided by Penetrate, are discussed in detail. Based on this model, we have some modifications. The modified physical model takes the effect of the geometry of drift tube, the cumulation of space charge, and ionization heating into account. Using this model, the evolution of highly charged ions in the EBIT is studied, the parameter studies are performed, and the comparisons with the experimental data of LLNL EBIT are made in detail. The results show that the modified physical model improves the model predication level greatly.