Dynamics of Particles Removal in Laser Shock Cleaning

摘要

Laser shock cleaning (LSC) has been proved an effective method to clean sub-micron and micron particles from solid surface during last five years. In this report, dynamics of the interaction between plasma shock wave and adhered spherical particles is analyzed in theory, considering the change of particle contact radius induced by the load of the shock wave. Analysis of the rolling mechanism at the initial contact of the shock wave with particles shows working gap has a serious influence to the cleaning and smaller diameter particles are more difficult to be removed with smaller cleaned area. Moreover, particle energy obtained from the shock wave is analyzed through which particle removal trace and cleaned area are studied combined reflection shock wave and irregular turnover of the particle into account. Removal of micron copper particles on a silica surface in air is experimented at different working gap. Results show that particles can be effectively removed within the suitable working gap, i.e., 0.8 mm for 150 mJ explosion energy, and higher working gap represents poorer cleaning efficiency. Moreover, the cleaning situation of the heavy contamination shows out an interesting phenomenon of the cleaned area (0.4cm~2) profile that is an ellipse caused by the non-uniform pressure distribution of plasma shock wave.