Development and Analysis of a Multiscale Numerical Model for Ionic Electrospray Emission*

Electrospray thrusters, a rapidly evolving class of electric propulsion devices, hold significant potential for enhancing the efficiency of miniaturized spacecraft. These thrusters operate by applying an electrostatic field to a liquid ion source, from which ions are extracted and accelerated, thereby generating thrust. Despite their high propulsive efficiency, particularly those operating in a purely-ionic emission regime using room-temperature molten salts (ionic liquids), their broader adoption has been limited. This is primarily due to various uncharacterized failure modes that impede their reliability in mission-critical applications.This study aims to address this gap by developing a comprehensive, multiscale numerical model of a purely ionic emitting electrospray thruster. The model is designed to guide future thruster design optimization and enhance their reliability. The methodology involves an electrohydrodynamic meniscus model that links upstream geometric and fluid properties to the current emitted at the interface. A dual direct simulation Monte Carlo and particle-in-cell approach, a method that simulates the movement of ions within the plume, is then implemented. Preliminary results indicate that this model can successfully predict the behavior of these thrusters under various conditions. This understanding can help identify key design parameters that influence thruster performance and reliability. By illuminating the dependencies of emission characteristics, this research provides valuable insights into potential strategies for mitigating electrospray failure mechanisms.