Numerical simulation of an ionic-liquid meniscus generating a purely ionic electrospray

Ionic liquid ion sources (ILISs) generate electrosprays by inducing emission of charged species from the menisci of moderately conductive ionic liquids (ILs) using a strong electric field. These electrospray sources have shown promise in micro-electric propulsion, especially when multiplexed as arrays of emitters. Though multiple emission modes have been observed, a pure ionic regime (PIR) yields the highest propulsive efficiency due to the large specific charge of the extracted species. This operational regime requires a high hydraulic impedance to balance the applied electric traction to sustain its low flow rate. To accurately model this system, the adoption of high-fidelity methods is imperative for interface capturing of ion transport in a rarefied external regime. Thus, a numerical study is presented to model the electrohydrodynamics of an IL meniscus attached to a porous reservoir held at a fixed electric potential. The upstream continuum model is used to investigate coupling conditions for a kinetic approach at and beyond the meniscus interface to simulate ion emission and far-field transport.