Atomization mechanisms of a wall-impinging jet in a shallow pool

Horiguchi, Naoki   ; Yoshida, Hiroyuki  ; Kaneko, Akiko*; Abe, Yutaka*

The atomization of a liquid jet in an immiscible liquid-liquid system is significant for the safety in the nuclear industry field. The Japan Atomic Energy Agency has developed an evaluation method of a melt fuel behavior as a liquid jet in an immiscible liquid-liquid system for subsequence using mechanistic numerical simulation and has investigated liquid jet behavior in a shallow pool through numerical simulations and experiments. The paper clarifies the atomization mechanism in the wall-impinging liquid jet. Herein, the atomization behavior in the wall-impinging liquid jet in a shallow pool in an immiscible liquid-liquid system was studied in terms of droplet formation and flow field using numerical simulation and the dispersed-phase tracking method. The results show that the droplet formation in the liquid film flow of the wall-impinging liquid jet had the three patterns, and we obtained the droplet properties immediately after droplet formation and developed the theoretical criterion regions using the dimensionless numbers for droplet formation. We characterized the patterns by comparing them with the regions and elucidated the droplet formation mechanisms depending on their sources. Moreover, we elucidated that the relationship between droplet formation as the local behaviors of the jet and atomization as the whole behavior.