场发射电推力器的参数选择与调控方法

场发射电推力器具有几种不同的发射模式，分别产生荷质比不同的带电液滴或带电离子，使得不同模式下推力性能差别显著。针对不同的空间应用，需要设计不同种类的场发射电推力器，使其达到相应的推力参数。为此对场发射电推力器的发射过程展开分析，确定了推力参数的调控方法。首先对场发射电推力器的基本工作原理进行了阐述，并对不同发射模式的基础物理机制进行了分析。在此基础上通过理论计算得出采用不同推进剂可达到不同发射模式这一结论，并最终得出推力器性能参数的调控方法，论证了推力性能受到推进剂种类和发射模式的影响，在离子发射模式下处于高比冲、低推力工况，而液滴发射模式下处于低比冲、高推力工况。此外推力参数还受到供给流量、外加电压等多种因素的影响。在得到推力器参数的调控方法后，设计了一种主动供给型离子液体电推力器，以离子液体EMI BF4作为推进剂，进行了相应的试验研究。通过改变外加电压，实现了对推力器推力性能的调控，证实了此调控方法的可行性。推力器达到的推力范围为1.6~10μN，比冲范围为154~978s。

Parameter selection and control of field emission electric thrusters

Field emission electric thrusters have different working modes, and can produce either droplets or ions. The thrust parameters change widely due to different charge to mass ratio of the charged particles.For different space applications, different types of field emission electric thrusters need to be designed to achieve the corresponding thrust parameters. The emission process of the thrusters and the selection and control method of the thrust parameters were discussed. The basic working principle of field emission electric thrusters and each working mode were discussed. The calculation results show that different emission modes can be achieved with different propellants, followed by the conclusion that the thrust parameters are controlled by the propellants′ species, extract voltage and propellant flow rate, etc. Design and experiment results of an ionic liquid electro spray thruster show that the thrust and specific impulse produced by the thruster can be modified by changing the applied voltage. The thrust and specific impulse can reach 16~10μN and 154~978s respectively.