Studying Of PIC/DSMC Method For Electric Propulsion Thruster Plume

Because of high specific impulse, the electric propulsion thrusters are widely used in spacecraft orbit transfer , pose contain and etc. But a major concern in the use of these devices is that the plumes may cause damage to the spacecraft. Therefore it is necessary to predict the contamination that the plume may cause to spacecraft. The goal of this study is to analyze and predict the plume flowfield of EP. After studying on the main character and solving methods of EP plume flow field, the numerical simulation of Hall effect thruster plume flow field is carried out. Analysis and prediction of the plume is achieved. The main achievements are as follows.Based on summarizing the working principle of usual EP thrusters, the characters of their plume flow field are analyzed. Because the EP plume has many distinctive features such as rarefied flow and inclusion of both ions and neutrals, continuum hypothesis is not fitted, the combination of the PIC and DSMC method are adopted. After constructing the collisional model between neutrals and ions , the motion of neutrals and various collisions is simulated using DSMC method. On the other hand, the motion of ions is simulated using PIC method. Therefore, the dynamic process of rarefied plasma can be studied with the combination of DSMC and PIC method. The method enlarges the respective applicable domain of both DSMC and PIC, which has major theoretical effects. As an important component of solving EP plume, both the electron fluid model and the solve of Poisson equation are adopted to calculate the potential.A software which can analyze and predict the EP plume flowfield is formed based on DSMC/PIC hybrid method and used to study the plume flowfield of a hall thruster. Such quatities as density distribution, potential distribution and current density of the plume are obtained. Comparation with experimental result testifies the correctness of both the method and the software. By changing entrance condition, it is found that decrease of ion and the neutral number density,injecting velocity at the thruster exit will curtain the deleterious effects the plume may cause to the spacecraft .The result of the study is the basis of the prediction of the EP thruster plume and gives a good reference for the whole design of the spacecraft.