The industrial application of the Kaufman ion thruster in its arc stage is limited owing to the instability of the discharge pulse.Presently,a complete prediction model that can predict the discharge pulse in the high...The industrial application of the Kaufman ion thruster in its arc stage is limited owing to the instability of the discharge pulse.Presently,a complete prediction model that can predict the discharge pulse in the high-current stage does not exist.In this study,a complete prediction model for the pulse in the ion thruster is established using the zero-dimensional plasma discharge model and equivalent circuit model.The zero-dimensional plasma discharge model is used to obtain the corresponding plasma parameters by calculating the beam current,discharge current,voltage,and gas flow under actual working conditions.The input parameters of the equivalent circuit model are calculated using empirical formulae to acquire the estimated discharge waveforms.The pulse waveforms obtained using the model are found to be consistent with the experimental results.The model is used to evaluate the process of rapid changes in plasma density.Additionally,this model is employed to predict changes in the pulse waveforms when the volume of the discharge chamber and grid plate transmittance are changed.展开更多
Like the hollow cathode,discharge instability also occurs during the operation of a plasma contactor.Voltage and current probes were employed to test the change of keeper voltage,keeper current,anode voltage,and anode...Like the hollow cathode,discharge instability also occurs during the operation of a plasma contactor.Voltage and current probes were employed to test the change of keeper voltage,keeper current,anode voltage,and anode current parameters with time under different working conditions.The anode current range corresponding to the discharge instability phenomenon is about 0.4 A to 1.2 A,and the emission characteristic curve in this area appears to bulge wherein the four parameters all produce different degrees of oscillation,the anode current oscillation being the greatest.Its waveform is considered to consist of a small-amplitude,high-frequency triangular wave and a large-amplitude,low-frequency sawtooth wave,and we have explained the shape of the wave.Each parameter shows hundreds of Hz in oscillation frequency and the phases of the four parameters appear to be regular.After fast Fourier transform processing,the frequency and amplitude of the main peak of the anode current oscillation tend to change with changes of the anode current,and there are differences in the trends under different keeper currents and xenon flows.展开更多
In the present work,the turbulent mixing process of a polydisperse quartz particle flow with a plasma stream generated by a radio-frequency(RF)inductively coupled plasma torch was numerically studied.The thermobaric s...In the present work,the turbulent mixing process of a polydisperse quartz particle flow with a plasma stream generated by a radio-frequency(RF)inductively coupled plasma torch was numerically studied.The thermobaric stress in the quartz particles under dynamic heating in a heterogeneous plasma flow was determined by a two-stage approximation approach.The effect of the presence of vacuoles in natural quartz on the particle thermobaric destruction conditions was studied.It was found that the equivalent thermal and baric stresses in quartz particles may significantly increase in the presence of vacuoles within a small gas volume fraction.The influence of the regime and energetic working conditions of an RF inductively coupled plasma torch system on the particle thermobaric destruction conditions was examined,and a recommendation was given to promote the degree of thermobaric destruction of quartz particles,which is of substantial importance for improving the overall enrichment efficiency of quartz concentrates.展开更多
基金the financial support from National Natural Science Foundation of China(Nos.11402025,11475019,and 11702123)the National Key Laboratory of Science and Technology on Vacuum Technology&Physics(No.ZWK1608)+1 种基金the Advanced Space Propulsion Laboratory of BICEBeijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology(No.Lab ASP-2018-03)。
文摘The industrial application of the Kaufman ion thruster in its arc stage is limited owing to the instability of the discharge pulse.Presently,a complete prediction model that can predict the discharge pulse in the high-current stage does not exist.In this study,a complete prediction model for the pulse in the ion thruster is established using the zero-dimensional plasma discharge model and equivalent circuit model.The zero-dimensional plasma discharge model is used to obtain the corresponding plasma parameters by calculating the beam current,discharge current,voltage,and gas flow under actual working conditions.The input parameters of the equivalent circuit model are calculated using empirical formulae to acquire the estimated discharge waveforms.The pulse waveforms obtained using the model are found to be consistent with the experimental results.The model is used to evaluate the process of rapid changes in plasma density.Additionally,this model is employed to predict changes in the pulse waveforms when the volume of the discharge chamber and grid plate transmittance are changed.
基金financial support from National Natural Science Foundation of China(Nos.11402025,11475019,and 11702123)National Key Laboratory of Science and Technology on Vacuum Technology and Physics(No.ZWK1608)Advanced Space Propulsion Laboratory of BICE and Beijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology(No.Lab ASP-2018-03)。
文摘Like the hollow cathode,discharge instability also occurs during the operation of a plasma contactor.Voltage and current probes were employed to test the change of keeper voltage,keeper current,anode voltage,and anode current parameters with time under different working conditions.The anode current range corresponding to the discharge instability phenomenon is about 0.4 A to 1.2 A,and the emission characteristic curve in this area appears to bulge wherein the four parameters all produce different degrees of oscillation,the anode current oscillation being the greatest.Its waveform is considered to consist of a small-amplitude,high-frequency triangular wave and a large-amplitude,low-frequency sawtooth wave,and we have explained the shape of the wave.Each parameter shows hundreds of Hz in oscillation frequency and the phases of the four parameters appear to be regular.After fast Fourier transform processing,the frequency and amplitude of the main peak of the anode current oscillation tend to change with changes of the anode current,and there are differences in the trends under different keeper currents and xenon flows.
基金supported by National Natural Science Foundation of China(Nos.52202460,52177128)National Key R&D Program of China(Nos.2020YFC2201100,2021YFC2202804)+2 种基金China Postdoctoral Science Foundation(Nos.2021M690392,2021TQ0036)Science Foundation for Youth Scholars of the Beijing Institute of TechnologyAdvanced Space Propulsion Laboratory of BICE and the Beijing Engineering Research Centre of Efficient and Green Aerospace Propulsion Technology(No.LabASP-2021-04)。
文摘In the present work,the turbulent mixing process of a polydisperse quartz particle flow with a plasma stream generated by a radio-frequency(RF)inductively coupled plasma torch was numerically studied.The thermobaric stress in the quartz particles under dynamic heating in a heterogeneous plasma flow was determined by a two-stage approximation approach.The effect of the presence of vacuoles in natural quartz on the particle thermobaric destruction conditions was studied.It was found that the equivalent thermal and baric stresses in quartz particles may significantly increase in the presence of vacuoles within a small gas volume fraction.The influence of the regime and energetic working conditions of an RF inductively coupled plasma torch system on the particle thermobaric destruction conditions was examined,and a recommendation was given to promote the degree of thermobaric destruction of quartz particles,which is of substantial importance for improving the overall enrichment efficiency of quartz concentrates.
