레이저 충격파 세정 공정 시 입자 거동 가시화

Visualization of particle behavior in the laser shock cleaning process

  Recent researches on cleaning technologies indicate that micro/nano-scale particle on solid surface can be removed successfully by laser-induced plasma/shock waves. Experimental and computational studies have been performed by several researchers. In this work, we visualize the behavior of 10um fluorescent particle in the laser shock cleaning process. The results are compared with those of two dimensional numerical simulations for the hydrodynamics and detachment of the particle including the effect of external blowing of N₂. It is found that the particle motion is sustained for a significantly long time ~ms after the shock passage. Most of the particles are captured by rotating vortices formed downstream of the shock wave. The external blowing by a nozzle eliminates the rotating flow and therefore substantially reduces the chance of particle redeposition.