Electrospray Thruster Simulation Using COMSOL Software And PIC Method

These days,space missions call for a rise in propulsion technologies capable of improving a satellite’s relative position and canceling small disturbances.The near-perfect technology that gives hope for these types of missions is colloid thrusters.These thrusters are electrostatic accelerators which,of course,do not rely on gas ionization known as plasma.They are tiny and operate at low power levels while having small plume divergence angles to avoid spacecraft contamination problems.Colloid thrusters provide low thrust(0.1 /0)8)4)0))which can be multiplied over and over by integrating them in micro fabricated arrays.A salient advantage is that with the appropriate choice of propellant and operating regime their specific impulse can be modified from 500 to 7000 seconds making them feasible candidates for a whole lot of mission profiles.In times past,a lot of research groups have tried to develop colloid thrusters;however,their basic physics are not well explained.Because of this,I have taken on the development of a numerical simulation of electrospray thrusters using COMSOL software and the PIC method to complement experimental and analytical research in the area.The goal of this project is to simulate the forming process of the Taylor cone with COMSOL multiphysics.The process of ionic liquid forming a stable cone under the action of a strong electric field force is simulated.To meet the requirements of micro propulsion in modern space missions such as orbit control and gravitational wave detection,this paper studies the ionic liquid thruster.In the process of constructing mathematical models,the structure mechanism and working process of electrospray are calculated theoretically.Some high-efficiency techniques of the ionic liquid thruster such as pure ion mode and pure droplet mode are derived.And for the thruster working in the mixed-mode,the ability of the thruster can be improved by increasing the drop charge mass ratio or reducing the ion charge mass ratio.The thrust and specific impulse of thruster depend on the charge mass ratio of charged particles,extraction voltage,current,and liquid flow.Increasing the charge mass ratio of particles,increasing the extraction voltage and flow rate are some of the steps taken to promote the increase of thrust and specific impulse.Still in this work,the distribution of electric field force,surface tension,volume force on the surface of the Taylor cone,and the change of velocity near the liquid surface are analyzed.The effects of voltage and flow rate on the electrospray development were calculated by constructing a two-dimensional axisymmetric model.Simulation results show that the array spacing can be expressed as a function of emitter diameter when the nozzle diameter is in the order of 8)～8)8).Finally,we use the particle in cell method to simulate a cubic domain.While the COMSOL RF module is used to simulate and calculate the thrust through three-dimensional modeling to obtain the model parameters,spatial electric field distribution,and other results.