Study of gas entrainment from free surface by vortex

Koizumi, Yasuo*; Ito, Kei; Ohshima, Hiroyuki; Otake, Hiroyasu*

Gas entrainment from the bottom of a container was examined in the case that there was a free surface with swirl flow and liquid flew out from an outlet at the bottom. Before the bottom of the vortex reached the bottom of the container, bubble-state gas entrainment from the tip of the vortex occurred and the bubbles flew out from the bottom outlet of the container. As the liquid velocity was increased, the bottom of the vortex invaded into the outlet piping and eventually air and liquid phase separation occurred in the piping. The flow state changed to a churn flow, and then to an annular flow and the entrained air flow rate increased considerably as the liquid flow rate was increased.