Simulation of liquid meniscus formation in the ionic liquid electrospray process

Abstract

Ionic liquid electrospray thrusters (ILETs) have advantages of high specific impulse, compact structure and low power, which are excellent candidates for the propulsion system of nanosatellites. Electrospray is the working principle of ILETs. Though tremendous efforts have been made to investigate electrospray, some aspects, such as the evolution of the menisci on the micropores of porous emitter tips and the transient response of the meniscus during the polarity alternation, need to be further understood. This paper presents a computation fluid dynamics (CFD) model to describe the meniscus formation in the ionic liquid electrospray process. The CFD model, based on the Taylor-Melcher leaky dielectric fluid theory and the volume of fluid (VOF) method, is validated by experiments. The evolution of the meniscus on the basis of a micropore is presented using two typical ionic liquids, EMI-BF4 and EMI-Im. The influences of the pore size, flow rate and applied voltage on the formation of the meniscus have been studied. Results show that a larger pore is more likely to start emission. And the time consumed for liquid meniscus formation is decreased with the increase of the applied voltage and flow rate. Further, it is found that alternation of polarity does not destroy the structure of the meniscus but retards the formation process. And a faster polarity alteration leads to a shorter delay of meniscus formation time.

Discharge in electrospraying of highly conductive aqueous solution coated with outer ionic liquid

“…Note that the present simulation only calculated the electrical parameters of the discharge process of coaxial electrospray at specific condition (Q NaCl = 1.5 nL s −1 , Q IL = 1 nL/s, V = 4.1 kV, the same as the condition in figure 7) without considering the movements of the fluids. The electric field simulation is formulated by solving the charge conservation equation, similar method has been used in previous studies [56][57][58].…”

Simulation of liquid cone formation on the tip apex of indium field emission electric propulsion thrusters

“…Recently, some CFD codes have been employed to simulate the dynamic behavior of cone formation of aqueous solution or ionic liquid. Sen et al simulated the cone-jet electrospray on carbon nanofiber emitters using a CFD code (FLOW-3D) and demonstrated the feasibility of these simulations [18]. Liu et al simulated the meniscus formation of an ionic liquid in the electrospray process and found that the alternation of polarity can delay the cone growth time [19].…”

Special issue on selected papers from CEPC 2021

“…1009-0630/22/070101+02$33.00 liquid meniscus formation in the ionic liquid electrospray process [8], simulation of the helicon plasma source in magnetoplasma rocket engine [9], numerical study of effect of aft-loaded magnetic field on multiple ionizations in Hall thruster [10], and the characteristics of plasma in a novel laser-assisted pulsed plasma thruster [11]. These papers reflect the latest progress in electric propulsion technology in universities, research institutes and aerospace industry departments of China.…”