Experimental study and theoretical development of liquid entrainment in T-junction with double inlets and single inlet of gas phase

The liquid phase entrainment through ver tical-up branch had been analyzed through scaled and full size of experiment since ADS-4 (the fourth-stage Automatic Depressurization System) valve adopted in advanced PWR (Pressurized Water Reactor). Most of the existed studies focus on the single inlet of gas whereas steam may flow from two sides of the T-junction during the blowdown of primary system. Hence the experimental study on liquid entrainment with double end inlets are carried out. The data on the onset of entrainment (OLE) turns out that double end inlets show small difference with single inlet, whereas the entrainment rate research have great difference with single inlet and there is more than 50% error between the data and existing theoretical models. According to the visible flow phenomenon and flow instability, a new entrainment rate model was proposed which can well predict the double-end inlets and single-inlet entrainment phenomenon with the error within ±20%.