Experimental Investigation Of A Kilowatt Cylindrical Hall Effect Thruster

Current electric propulsion is mainly applied to the maintenance of satellite northsouth position,orbital correction and other small impulse space missions,along with human Space exploration,orbital enhancement,deep space exploration and other tasks require thrust and total specific impulses.Developed high-power thruster will inevitably become the major trends of the propulsion system.Hall thrusters have no irreconcilable contradiction to high power development,However,the size of the current high-power single-ring Hall thruster is large.Based on this,this paper proposes a magnetic circuit configuration that improves Hall thruster power density and thrust density,Discharge experiments and optimization were performed on experimental prototypes.The distribution of the working gas in the channel influences the Hall thruster ionization.Firstly,the research is based on the gas supply mode of the gradually expanding ring and the cylinder combined channel of the experimental prototype.Compared with the axial gas supply,supplying gas along the bisector of the divergent channel angle can make the ionization zone close to the centerline of the channel.At this time,the ion loss on the wall surface is small,the utilization rate of the working gas and the current utilization rate are higherr,and the voltage utilization rate is also higher.But the plume divergence angle is smaller and thrust is higher.The discharge plume of the experimental prototype has a hollow cone,which is different from the traditional plume distribution.Therefore,the influence of magnetic field changes on the plume is studied.The results show that the larger the angle between the magnetic lens and the axial direction in the channel,the angle at which the hollow conical plume converges.The closer to the exit of the channel,when the direction of the magnetic lens coincides with the axial direction,the plume mode is changed to diverge the plume as a whole;during the transition of the plume from the hollow cone to the divergent plume,the angle between the magnetic lens and the axis is reduced Smaller,lower electronic conductivity,higher working efficiency,and higher current utilization.At the same time,voltage utilization is improved,plume divergence is reduced,and anode efficiency and thrust are increased.Secondly,the Hall thruster discharge is performed in the ceramic channel,and the plasma interacts with the wall surface.Therefore,the ceramic channel configuration also affects the discharge.This article analyzes the length and configuration of the outer wall surface of the channel.The length of the outer wall of the channel is too short,and the work gas is poorly constrained and the utilization rate of the working gas is low;the outer wall surface of the channel is too long,and part of the ions are compounded at the outlet of the channel and the wall surface,resulting in overheating of the ceramic;the length of the outer wall surface of the ceramic is increasing.The decrease of the utilization rate and the increase of the plume divergence angle require balancing the utilization rate of the working gas,the voltage utilization rate,the plume divergence angle,and the wall ion energy deposition,so as to find the characteristic length of the outer wall surface with the highest discharge efficiency.The Configuration of the inner wall surface of the channel is also studied.Compared with the progressively expanded annular and cylindrical combined channel,the ionization in the complete annular channel is closer to the channel interior,and the ion loss is serious on the wall surface,but the angle between the magnetic lens and the axial direction is small.The utilization rate is high,the plume divergence angle is small,and the thrust is large;due to the increase of the proportion of electronic current,the anode efficiency is lower than the combined channel.Finally,the means to expand the scope of the thruster's operating parameters are explored.The starting point is to increase the magnetic field gradient in the channel and to extrapolate the ionization zone;accordingly,a magnetically permeable anode is designed based on the prototype magnetic circuit configuration.Magnetically conductive anodes are axially extended on the basis of non-magnetically permeable anodes.Compared with non-magnetically permeable anodes,magnetically conductive anodes increase the upper limit of discharge voltage,but the excitation adjustment range is narrow,and as the magnetically conductive anode increases axially,The gradient of the magnetic field in the channel increases,the ionization zone moves toward the outside of the channel(axially increased 2mm magnetically conductive anode sputtering zone pushes 0.8mm outwards),the plume divergence angle increases,the distance between the ionization zone and the anode surface shortens,and the electron loss is greater The current utilization rate is reduced and the anode efficiency is reduced.The magnetic field distribution of the magnetic anode Mag-I discharge channel is the same as that of the non-magnetic anode,the corresponding flow area is increased,the density of the working medium in the channel is reduced,the utilization of the working medium is reduced,and the thrust is small;the magnetic anode Mag-II is The magnetic field strength and gradient increase,the utilization of the working medium improves,and the thrust increases...