Gravity-driven countercurrent two-phase flow during filling of an unvented vessel Original Research Article

Countercurrent two-phase flow associated with filling of sealed vessels via gravity-driven liquid injection through inclined channels was experimentally studied and analytically modeled. Experiments were performed using transparent tubular test sections connected at one end to the bottom of a large, open water tank, and at the other end to an unvented tank. The test section parameters (including the channel diameter (1.27–2.54cm), length (30.5–122 cm), angle of inclination with respect to horizontal plane (0–30°), and the empty volume in the sealed vessel) were systematically varied. Flow regimes in the test section were recorded and transient flow rates were measured during the experiments. Oscillatory, and intermittent stratified slug, were dominant flow regimes in most tests. The quasi-steady liquid superficial velocity in the test section was sensitive to the test section dimensions, and varied in the range 0.04–0.95 m s−1. These flow regimes were mechanisally modeled. The models are shown to satisfactory predict the measured hydrodynamic parameters.