Modeling of Gravity-Driven Oscillatory Countercurrent Two-Phase Channel Flows

Gravity-driven countercurrent two-phase flow, in channels connected to a sealed tank at one end and open to the atmosphere at the other end, was analytically studied. This type of gravity-driven countercurrent two-phase flow can occur during the operation of passive safety coolant injection systems of advanced reactors. A mechanistic model was developed for the oscillating flow regime, which occurs in inclined channels with a side-entry configuration when the channel angle of inclination with respect to the horizontal plane is more than 10 deg and in channels with a bottom-entry channel-tank interphase. The model was shown to satisfactorily predict the experimental data.