Spattering behavior induced by cavitation bubble collapsing nearby gas-liquid interface

Kawashima, Hiroyuki; Kurosawa, Takuma*; Teshigawara, Makoto   ; Naoe, Takashi   ; Tanaka, Nobuatsu*; Futakawa, Masatoshi  ; Kogawa, Hiroyuki  

Laser cutting is expected for reducing the volume of radioactive components by taking account of radioactive levels. The scattering of radioactive dust such as fume and spatter, which is generated throughout the laser cutting process, gets to be a major issue for practical usage in cutting highly radioactive substances. One of driving forces of the spatter is likely to be attributed to the cavitation bubble collapsing caused by rapid thermal loading due to laser irradiation. In order to elucidate the mechanism of spattering, the technique of spark discharge in water was availed to generate the cavitation bubble. The growth and collapse behaviors influenced by the interaction between a free surface and bubbles resulting the spattering phenomena are observed by using an ultra-high-speed video camera, and the numerical simulation was carried out as well.