Mitigation technologies for damage induced by pressure waves in high-power mercury spallation neutron sources, 2; Bubbling effect to reduce pressure wave

Futakawa, Masatoshi  ; Kogawa, Hiroyuki  ; Hasegawa, Shoichi   ; Naoe, Takashi   ; Ida, Masato; Haga, Katsuhiro  ; Wakui, Takashi  ; Tanaka, Nobuatsu*; Matsumoto, Yoichiro*; Ikeda, Yujiro

The life time of mercury target will be reduced by the cavitation damage induced by pressure waves. Micro-bubble injection into mercury is one of prospective technologies to mitigate the pressure waves. We have carried out damage tests using mercury loop with an impact generator to evaluate the bubbling effect on the pressure response and cavitation damage. The impulsive pressure was hardly changed but the damage was reduced remarkably by the micro-bubble injection. Numerical simulation was performed to investigate the bubbling effects. It was understandable that micro bubbles suppressed cavitation inception.