Experimental study on gas entrainment by bathtub vortex

Ito, Kei*; Ito, Daisuke*; Odaira, Naoya*; Saito, Yasushi*; Song, K.*; Ezure, Toshiki ; Matsushita, Kentaro ; Tanaka, Masaaki  

The entrained gas flow rate by a bathtub vortex must be evaluated to achieve stable operation of a sodium-cooled fast reactor. In this study, a simple vortex-type gas entrainment experiment is conducted to evaluated the entrained gas flow rate under various conditions of free surface level, downstream pressure and suction pipe diameter. As a result, it is clarified that the entrained gas flow rate increases with the decrease in the downstream pressure. Based on the experimental result, we model the annular two-phase flow in the suction pipe and propose a new evaluation model of the entrained gas flow rate in which the influence of the downstream pressure.