毛细管放电型脉冲等离子体推力器输出特性分析

Analysis of Output Characteristics of Capillary Discharge Based Pulsed Plasma Thruster

为了研究毛细管放电型脉冲等离子体推力器输出特性,借助电学诊断手段展开实验研究,获得了推力器典型放电波形,系统研究了不同毛细管内径和施加电压对等离子体等效阻抗、沉积能量效率的影响规律。利用微冲量测量台架,测试了不同参数下毛细管推力器输出元冲量,并通过计算获得了推力器比冲、总体效率的变化规律。实验结果表明,当毛细管内径不断增大时,能量沉积效率不断下降,元冲量下降,比冲降低。主电容电压增大时,放电能量不断增大,能量沉积效率降低,元冲量和单次等效烧蚀质量不断增大,但推力器比冲和总体效率均先增加并趋于稳定。当毛细管腔体长度为16mm,内径3mm,主电容2.5μF,充电电压为2kV时,输出元冲量350.79±7.50μN·s,比冲531s,总体效率可达18.3%。

The output characteristics of the capillary discharge based pulsed plasma thruster is investigated experimentally.The typical discharge waveform was achieved with the electrical measurement tools.The effects of the cavity diameter and applied voltage on the equivalent plasma resistance and energy deposition efficiency were studied.With the thrust balance for micro impulse measurement,the output impulse bit under different parameters was measured and the specific impulse and overall efficiency were calculated.The experimental results show that with the increasing of the cavity diameter,the energy deposition efficiency,impulse bit and specific impulse decrease.With the increasing of the applied voltage on the main capacitor,the discharge energy,impulse bit and equivalent ablation mass per shot increase while the energy deposition efficiency decreases.Meanwhile,the specific impulse and overall efficiency increase firstly and finally tend to be stable.Finally,the performance parameters of impulse bit 350.79±7.50μN·s,specific impulse 531 s and efficiency of 18.3% were achieved under the condition of cavity length of 16 mm,diameter of 3 mm,main capacitance of 2.5μF and applied voltage of 2 kV.