Influence of air entrainment on the liquid flow field caused by a plunging jet

Plunging jets play an important role in nuclear reactor safety research. In the actual paper the case of the strainer clogging issue is considered. During a loss of coolant accident (LOCA) insulation debris might be released near the break. Fractions of the released insulation debris can be transported into the reactor sump, where it may perturb/impinge on the emergency core cooling systems. According to the considered scenario, the water ejected by the anticipated break falls several meters on to the sump water surface. On its way, the jet is mixed with air. Furthermore, air bubbles are entrained by the impinging jet. The entrained gaseous bubbles will rise and have an additional influence on the flow field. The jet-induced flow into the sump will sensitively influence the fiber transport.
In the CFD calculations presented in the paper the consequences of the entrained air on the liquid flow field, on the fibre deposition and on the temperature mixing are investigated and compared to experiments.