Abstract The electrospray thruster relies on a large number of emission sites that simultaneously emit ions or charged droplets to generate thrust. The operation uniformity of the emission sites is of great significance to ensure the stable work of the thruster and improve its thrust level. However, there was little in-depth study of it before, especially of its influence on the thruster's characteristics. To this end, four porous electrospray thrusters with different degrees of non-uniform operation of emission sites were adopted, and their emission site distribution characteristics, volt-ampere characteristics, and current fluctuation characteristics were investigated. Emission site distribution of all thrusters showed a certain degree of unevenness. On their emission surfaces, there were some dark zones where few emission sites located on, highlight zones where emission sites were too concentrated, and intermediate zones where emission sites repeatedly appeared and disappeared. The appearance of a dark zone could cause a decrease in the growth rate of emitted current with voltage, and electric sparks that happened in the highlight zones could directly interrupt the operation of thrusters and suppress the increase of thrusters' thrust level. A periodic fluctuation, which should be caused by the flow rate difference between emission sites, emerged on the plume current of almost all thrusters. Various experimental results indicated that part of the liquid in high-flow-rate areas spread to low-flow-rate areas while the current fluctuated periodically. It could effectively reduce negative effects caused by the non-uniform operation of emission sites. The flow resistance of one of the four thrusters was greatly reduced. As a result, the operation uniformity of emission sites was greatly improved, but the overflow problem in high-flow-rate areas was exacerbated.

中文翻译：

---

发射点非均匀运行对多孔电喷雾推进器特性的影响

摘要 电喷雾推进器依靠大量的发射点同时发射离子或带电液滴来产生推力。发射场的运行均匀性对于保证推进器的稳定工作和提高其推力水平具有重要意义。然而，之前对其深入研究的很少，尤其是它对推进器特性的影响。为此，采用了4个不同程度的发射场不均匀运行的多孔电喷雾推进器，研究了它们的发射场分布特性、伏安特性和电流波动特性。所有推进器的发射点分布均呈现一定程度的不均匀性。在它们的发射面上，有一些暗区，很少有发射点位于，突出排放点过于集中的区域，以及排放点反复出现和消失的中间区域。暗区的出现会导致发射电流随电压的增长速度下降，而高亮区发生的电火花会直接中断推进器的运行，抑制推进器推力水平的增加。几乎所有推进器的羽流都出现了周期性波动，这应该是由排放地点之间的流速差异引起的。各种实验结果表明，在电流周期性波动的同时，高流速区的部分液体扩散到低流速区。可有效降低排放点运行不均匀带来的负面影响。四个推进器之一的流阻大大降低。从而大大提高了排放点的运行均匀性，但加剧了高流量区域的溢流问题。