Dynamic responses of a solid wall in contact with a bubbly liquid excited by thermal shock loading

Futakawa, Masatoshi  ; Naoe, Takashi   

It is proposed that microbubbles are injected into the liquid metal to mitigate the impulsive pressure waves of spallation neutron target by means of absorption and attenuation effects. These effects are dependent on the relationship between bubble size and the rate of pressure increase. In the present experiment, a very rapid rise in pressure in the order of MPa/s, equivalent to the rise in pressure due to proton beam injection, was simulated by the electric discharge method in bubbly water to investigate the impulsive pressure mitigation effect of injected microbubbles. The solid wall response was measured using an accelerometer, and the dynamic responses of microbubbles were observed using an ultra-high-speed camera filming at frame/sec. It was confirmed from the experimental results that microbubbles are effective in reducing impulsive pressure waves and to suppressing the impact vibration of the solid wall in contact with the liquid.