Numerical prediction of gas entrainment in the 1/1.8 scaled partial model of the upper plenum

Uchibori, Akihiro ; Sakai, Takaaki; Ohshima, Hiroyuki

Numerical analysis of the gas entrainment experiment using the 1/1.8 scaled partial model of the designed upper plenum of a sodium cooled fast breeder reactor was performed. The objective of this work was to investigate capability to simulate the flow field in the upper plenum and to confirm applicability of the newly developed assessment method of gas entrainment. The results of the numerical analysis showed that a vortex periodically appeared around the pipes which exist in the flow passage. The appearance position of the vortex, the calculated velocity profile around the vortex and the calculated circulation agreed with the experimental results. Possibility of gas entrainment occurrence was assessed from the numerical results by using our assessment method. For all the analysis cases, occurrence or non-occurrence of gas entrainment was correctly predicted by our method.