Study On Ionization And Thermal Structure Optimization Of Low Power Kryptonian Hull Threster

Hall thruster is one of the most mature electric propulsion systems in the world.Due to the development of Hall thruster in recent years,its working xenon is not only facing the reduction of resources,but also the price is greatly increased,which makes the cost of Hall thruster rise.In order to solve the problem of working medium,krypton gas,which is similar to xenon,is chosen as the substitute.Compared with xenon,krypton is not only rich in reserves and low in price,but also higher in theoretical specific impulse than xenon.However,its ionization performance is poor and the thermal problems of thrusters are serious,especially the low power is more serious.Therefore,it is of great significance to study the charge ionization optimization and thermal structure optimization of low-power krypton working medium Hall thruster.The reason of low ionization rate of low power krypton working medium Hall thruster is analyzed.The influence of the problem of the prolongation of ionization region and the increase of electron current ratio on ionization rate is further analyzed.Then,the ionization optimization is carried out from two aspects: increasing the density of krypton gas and improving the collision frequency.Taking the 275 v discharge voltage and 30 sccm working medium flow as an example,PIC simulation calculation is used to find that the ionization rate has been improved by 5% and 25%respectively after the above two optimization.Secondly,the heat problem is optimized by the heat deposition on the wall,the main heat source of the thruster.Firstly,the wall heat deposition is divided into the wall electron heat flow and the wall ion heat flow.The change characteristics of the heat deposition with the flow of the working medium and discharge voltage are analyzed from the incident flux and the incident energy respectively.According to the characteristics,the electron heat flow and ion heat flux on the wall are optimized respectively,and the effectiveness of the optimization measures to reduce the heat deposition on the wall is verified.Then,the heat problem is optimized from the aspect of heat dissipation structure.Firstly,the thermal path of the two main heat sources of the original thruster,anode and wall heat flow,is simulated by ANSYS thermal steady-state module.Then,the new thruster structure is designed to reduce the heat problem of the thruster effectively and the experimental verification is carried out.Finally,the performance of the new thruster is verified.The original thruster is improved in combination with the contents of the previous chapters,which is more suitable for the low-power krypton working medium.Firstly,the mechanical simulation of the system is carried out by ANSYS,such as sine vibration assessment,random vibration assessment and impact assessment.The results show that the thruster meets the engineering requirements of space mission.Then,the discharge performance and the working stability test are compared.The experimental results show that the performance of the thruster is improved in all aspects...