Numerical Simulation Of Plasma Plume Of Pulsed Arc Vacuum Based On Coupled With Flow Field And Electric Filed

Plasma plumes are mainly found in electric thrusters and plasma devices,The plasma generated by the electric propeller is mainly freely diffused in a vacuum environment.Compared with the plasma plume generated by electric propulsion,the plume generated in the plasma device is bounded by the wall during its diffusion process,including wall reflection.,wall chemical reaction and plasma sheath.This paper mainly considers the influence of wall reflection,wall chemical reaction and electric field on the transport characteristics of flow field.Therefore,this paper mainly carries out the following research:First,the research on the model of gas wall interaction is carried out.Since the effect of the wall at a small scale will have a large impact on the flow field,it is important to select a reasonable model of the wall wall interaction.By comparing the calculation results of different wall reflection models and different adjustment coefficients,the influence law of different wall reflection models and different adjustment coefficients on the flow field is analyzed,which provides guidance for the subsequent selection of reasonable wall reflection models and adjustment coefficients.On the basis of considering the gas wall reflection model,the chemical reaction between the particles and the wall surface is added,including the charged ions from the wall surface to obtain the neutral particles,and the particles and the wall surface composite reaction.Secondly,based on the existing DSMC/PIC hybrid program,the wall reflection model and the wall chemical reaction model are added to the mixing program to consider the influence of the wall reflection model and the wall chemical reaction on the flow field under the electric field,and consider the wall surface.The influence of chemical reaction on the potential distribution in the flow field,and finally the influence of the chemical reaction between the charged ions and the wall on the neutral particles in the flow field.Two sets of grid technologies are implemented in the DSMC/PIC hybrid program,that is,DSCM and PIC respectively use their respective grids to perform neutral particle motion,collision and chemical reaction processing in the DSMC grid,in the PIC grid.The motion of the charged particles and the solution of the node potential are realized.Finally,dynamic load balancing of DSMC parallel programs is implemented.In the early stage of the research group,the initial parallelism of DSMC has been realized.Based on the background grid technique,the weight of the grid is calculated by calculating the number of particles in the unstructured grid,and then the grid is partitioned so that the number of particles in each region is equivalent.And after each promotion for several times,the load balance between the processes is judged.If the load balance does not meet the requirements,the grid is newly partitioned,and the load balance between the processes is enhanced.