Effect of solid wall distance on jet ejected by bubble collapsing in narrow channel

Naoe, Takashi   ; Wan, T.; Kogawa, Hiroyuki  ; Futakawa, Masatoshi  

Pressure wave propagation and following cavitation bubble and liquid jet from free-surface were analyzed through the high-speed photography method to study the effect of gas wall on pressure wave mitigation in mercury target for J-PARC. Spark discharge system was used as the pressure wave generator in acrylic tube filled with water. Distance among the source of pressure, the wall, and free-surface were parametrically changed in order to investigate the effect of the boundary conditions on jet behaviors. It was found that the velocity of liquid jet is changed correlated with the both of distances from free surface and wall. Velocity of jet is sufficiently smaller than the velocity of microjet (100200 m/s), which is emitted during the collapsing of cavitation bubble and is dominant factor to produce cavitation erosion. Therefore, it was suggested that the gas wall has the potential to reduce the cavitation damage of the mercury target.