Bubble flow simulations in target vessel

Haga, Katsuhiro  ; Kogawa, Hiroyuki  ; Wakui, Takashi  ; Naoe, Takashi   ; Futakawa, Masatoshi  ; Yamazaki, Shogo*; Tanaka, Nobuatsu*

Pitting damage on the target vessel wall caused by the pressure wave is one of the crucial issues to realize a pulsed high-power mercury target for spallation neutron sources. Micro-bubbles injection into mercury is one of prospective technologies to mitigate the pressure waves. As one of the studies for bubbling system design for pitting damage mitigation, preliminary simulation of bubble flow field in the actual target vessel was carried out and the optimal condition of bubble injection was investigated. The simulations were carried out with FLUENT. In two dimensional simulations, the bubbles of 50 m diameter could be carried more than 2000 mm, which corresponds to the length of the target vessel, with small rising height. Then three dimensional simulations were carried out for the case of the bubble diameter of 50 m and 500 m. As results, we could have prospect that bubbles are distributed to the desirable regions when they are injected in proper position according to the bubble diameter.