Numerical Simulation Of Plasma Plume Of Pulsed Arc Vacuum Based On DSMC/PIC Parallel Algorithm

In order to meet the demand of the design of the pulsed vacuum arc in the future,the characteristics of the evolution and the mechanism of energy transportation of the plasma plume should be predicted very well.The DSMC/PIC(Direct Simulation Monte Carlo/Particle-in-Cell)coupling algorithm realizes the numerical simulation of the plasma plume field by simulating the real physical process of the particles in the flow field,reveals the distribution evolution process and transport characteristics of the pulse vacuum arc plasma,and improves the performance of plasma devices,providing theoretical basis and guidance.The main content of this article contains:Research on the split-merge process of simulated molecules was carried out.Both DSMC and PIC arrange a large number of simulation molecules in the calculation area,and the simulation molecules represent a large number of real particles.In the plasma plume field,the distribution of particles is distinctly non-uniform.If the number of simulated molecules in the grid unit remains unchanged,the local particle distribution cannot be truly reflected.This paper has carried out the research on the split-merge process of simulated molecules.According to the distribution of real particles,the number of simulated molecules in a certain area is changed,so as to improve the accuracy of numerical simulation and save computer memory and time.DSMC/PIC parallel algorithm program was developed.As the scale of numerical simulation increases,the original serial calculation program cannot withstand the huge amount of grids and particles.Therefore,based on the original DSMC/PIC serial program of the research group.This paper adopts the message passing model(MPI)partition parallel strategy,and divides the unstructured grid based on the METIS＿Part Graph Kway function in the Metis tool to realize the parallel program.The design and test results verify the correctness of the parallel program,which can be further used for large-scale numerical simulation calculations.Parallel calculation of large-scale DSMC/PIC numerical simulation based on the super-computing platform was realized.The program has further developed the computational ability of reaching millions of magnitudes of grid and tens of millions of particles.The parallelism was tested on the super-computing platform.The result shows that the parallel computing result conforms to the laws of physics.The parallel performance monitoring results show that the efficiency of parallel computing is significantly improved.Therefore,the DSMC/PIC parallel algorithm can meet the requirements of large-scale numerical simulation of the plasma plume field.