Multiphysics Simulation And Performance Analysis Of High-power Hall Thruster

High specific impulse,large thrust and long life are favorable features of high-power hall thrusters.Unique application advantages in large-scale space missions such as deep space exploration,interstellar navigation and space cargo transportation are shown thanks to high-power hall thrusters.To improve the design efficiency of the thruster and investigate the influence of thermal load on the thruster performance,PIC/MCC/DSMC hybrid calculation,magnetic field calculation and finite element analysis are used to study the multiphysics distribution,temperature change,specific impulse and thrust.Considering a 50 k W Hall thruster as the research object,a twodimensional Axisymmetric calculation model is established.Based on the assumption of quasi-electrical neutrality,considering the collision between particles as two-body collision and neutral atoms as background gas,thrust under the standard condition(50k W,86.4mg/s)is 2.2N and the specific impulse is 2598 s.Compared with the experimental results of similar thrusters in literature,the errors are 5.18% and 3.35%.Various conditions(400V-600 V,69.12mg/s-103.68mg/s)are calculated to obtain the ion number density,electronic temperature distribution and ion axis velocity.Results show that voltage enhancement intensifies the particles interaction and ion axis velocity increases equally.Flow rate variety affects the electron temperature and ion number density distribution.Discharge voltage increase results the thrust and specific impulse increasing while mass flow only influences the thrust.Based on the wall energy deposition model,the contribution of the plasma inside the thruster to the temperature increase is explored,and the temperature distribution of the thruster under various working conditions is calculated.The maximum temperature of the thruster under standard conditions is 678.4℃,which is located on the inner wall of the discharge channel near the exit.Heat loss power of the thruster accounts for 15.94%in the standard condition.The increase in mass flow and discharge voltage both cause the temperature rise of the thruster.The temperature change of the thruster caused by the mass flow change is stronger than the temperature change caused by the discharge voltage change under the same change range condition(20%).The magnetic field appears nonlinear attenuation with temperature rise,and the binding effect of the magnetic field on the particles is enhanced in the first half of the discharge channel.The thruster magnetic confinement performance decreases.Compared with the results obtained under ideal magnetic field conditions,the calculated thrust and specific impulse considering the magnetic field changes show an attenuation trend.The maximum attenuation ratio is 8.4%.The increase in temperature causes the performance of the thruster to decrease.In order to reduce the overall temperature of the thruster,it is proposed to reduce the visible emissivity of the ceramic material wall surface of the discharge channel and magnetic shielding structure,change the excitation structure to permanent magnets and add non-magnetic heat conduction structures on the surface of the anode base and magnetic shielding structure.The above research results provide theoretical support and reference basis for the optimization design of high-power hall thruster and ground experiments.