Numerical simulation of welding aerosol diffusion based on plasma flow characteristics

Abstract

The welding plasma flow and the turbulent diffusion of aerosol were explored in this study to describe the diffusion of welding aerosol particles more accurately. A new simulation method for welding aerosol pollution sources was applied in this study based on considering the momentum transfer between multiphase flows. The effect of distance and angle between welded electrodes on plasma flow was evaluated through CFD numerical simulation and visualization experiment. The changes in the initial positions of welding aerosol particles under different plasma morphological characteristics were evaluated. The action mechanism of the local flow field on aerosol particle trajectory was evaluated under different working conditions. Finally, the diffusion characteristics of aerosol particles with different particle sizes were explored. The results showed that the distance and angle between the anode and the cathode of the welding affected the plasma flow morphology and stability, and thus affecting the diffusion trajectory of aerosol particles. The effect increased when the distance to the welding spot was small. The proportion of particles that diffused to quadrants II and III increases from 50% to 87.4% when the polar angle decreased from 90° to 30°. Particles with particle size over 1μm had the highest airflow dispersion, and their RDR was up to 71, whereas those with a particle size less than 0.15μm had an RDR of 49 due to the effect of Brownian motion and molecular slip.