| Plasma jet is generated by using the interaction between current and magnetic field to make gas jet in high speed. This paper carried out experimental and simulation research to the flow characteristics of plasma jet, of which the achievement provided the theoretical reference for the plasma jet in the application of promoting device.(1)This paper established the physical and mathematic model of coupled magnetic fluid, bases on magnetohydrodynamics (MHD).And it used the Fortran programming language to programme the simulation software of magnetohydrodynamics, and coupling calculate the magnetic field and fluid field in order to consider the effect of Lorenze force of electromagnetic field on ionizated fluid. It got the flow parameters of magnetic fluid field flowed over the blunt copper cylinder by using the simulation software and got the evolutionary process of magnetic fluid flowing passing by the wall. The simulation results were compared with experimental results, which verified the reliability and precision of the simulation software.(2) The simulation software was used to simulate the flowing process of the plasma jet of subsonic-cylindrical nozzle and analyze the influence of the parameters of inner fluid field to the plasma jet. The result showed that the physical change of outlet of inner nozzle of subsonic plasma jet flow,and the pressure on the nozzle appeared concussive change and the amplitude became smaller along the axial direction.Finally,it became stable to external nozzle;The overall tendency of the velocity and the tubulence energy along the axis became smaller concussivly.However,the temperature along the axis became bigger and then smaller.(3) The simulation and experiment were used to study the flowing process of plasma jet in supersonic Laval nozzle. And this paper analyzed the influence of the parameters of electromagnetic coupled field to the flowing process of plasma jet. This paper studied the characteristics of temperature field of plasma jet fluid field of nozzle in different working medium environment and the effects to nozzle structure. At the same time, in order to analyze the ablation influence of water cooling system to the exit of nozzle wall, this paper designed a water-cooling device and used the experiment way to analyzed the influence to the outlet temperature of nozzle of the cooling system. The results showed that the jet pressure, velocity, temperature and turbulent kinetic energy reached peak in the position of nozzle throat,then the pressure decreases rapidly and quickly stabilized and the temperature decreased gradually along the axial direction in the expansion section. the jet temperature peak exceed 1000℃ without water cooling, while jet temperature peak decreased obviously with water cooling.The research results of this paper provided a theoretical basis for the application of plasma jet. |
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