The Research Of The Influence Of Wall Material On The Discharge Process Of Hall Thruster

Hall thruster has been used widely in orbit correction and station-keeping of geostationary satellites for the advantage of high specific impulse, long lifetime. Along with the development of deep space exploration, high-power hall thruster is the inevitable development trend. As an important part of hall thruster, the wall plays an essential role in the discharge performance and lifetime of the hall thruster. For high power hall thruster, the importance of the wall is mainly manifested in the following two aspects: the influence of surface effect of high-power hall thruster on the discharge performance; the influence of the surface erosion on the hall thruster discharge performance and lifetime.In this paper, the wall effect and wall erosion problems were studied respectively by establishing the two-dimensional calculation model in the channel, and using the hybrid particle in cell simulation method. Firstly, this paper used the secondary electron emission model of wall material to get the fitting results of four common kinds of wall materials, Al2O3,BN, SiC, and graphite. And this paper simulated the distribution of the parameters in the channel of thruster under the conditions of all the four materials. By comparing the simulation results, this paper summarized the influence of secondary electron emission coefficient of wall material on the parameter distribution in the channel of the thruster.Secondly, this paper simulated the influence of internal and external wall inconsistencies and high radial magnetic field gradient on the discharge process of the thruster. On this basis, this paper tried to change the influence of increasing of radial magnetic field gradient on the performance of thruster by changing the wall materials. And by changing the material of the acceleration region near the wall, this paper compared different sets of wall materials by changing the wall materials of the vicinity of acceleration region. Finally, this paper studied the wall erosion problem, analyzed the wall erosion production of BN material, and simulated the discharge process of the SPT-100 hall thruster in different period of lifetime. And this paper simulated the distribution of the wall erosion production in the different time period,analyzed and summarized the influence of wall erosion on the thruster discharge performance.