超声电喷推进机理研究

超声电喷推进是一种新型的电推进技术，主要用于解决胶体推力器等电推力器发射点集成困难、发射点数密度低的问题。通过将超声振动产生的大量微细驻波作为发射源，超声电喷推进将从根本上提高发射点的数目和密度，形成较大的推力密度。文章对超声电喷推进的发射机理进行了研究，得到相应的理论发射模型。通过对发射表面上微细驻波的形成过程、带电液滴的分离过程进行理论分析，建立了静电场条件下微细驻波波峰临界状态的平衡方程，推导出微细驻波波峰局部半径以及发射液滴尺寸的理论解，并提出了发射电流、比冲和推力的估算方程。在此基础上，分析了极间电场强度、超声振动频率、超声振动功率、推进剂性能黏度、推进剂表面张力系数和电导率对超声电喷推进性能的影响规律，并进行了试验验证。

Study on emission mechanism of ultrasonically electric propulsion

To improve the thrust of colloid thrusters by increasing the number of emitters, a novel electric propulsion method named ultrasonically electric propulsion (UEP) was proposed.The dense capillary standing waves produced by ultrasonic vibration are the emitters,so the number and density of emitters are improved fundamentally and relatively high thrust density appears.The emission mechanism of UEP was analyzed and the corresponding emission model was developed. Through theoretical analysis on the formation of capillary standing waves and the emission of the charged droplets, the relationship among the surface tension, inertial force and electrostatic force at the crests of standing waves was introduced. Furthermore, the radius of the standing wave crests and the diameter of the charged droplets were theoretically solved. The estimation equations of spray current, specific impulse and thrust were proposed. Based on the theoretical analysis, the influences of the electric filed strength, ultrasonic vibration frequency, ultrasonic vibration power and propellant on the performance of UEP were analyzed and experimentally verified.