CHARACTERISTICS OF TWO-PHASE FLOW IN NETWORK BRANCHES.

Dividing and combining two-phase flows are encountered in many engineering systems in the power and process industries. A particular case of interest is that of loss-of-coolant accident (LOCA) in nuclear reactor safety analysis. This requires the accurate prediction of phase and pressure distribution for steam-water flow in complex branching conduits. In the present work, the results of an experimental investigation into the characteristics of dividing steam-water annular flow are presented. The experimental facility allowed for measured amounts of steam and water to be mixed to thermodynamic equilibrium and delivered to a horizontal tee test section. The measurement systems allowed the time averaged distributions of pressure and void fraction, flow quality and total flow rate in each leg of the tee to be determined. A set of detailed experiments was carried out to isolate the effects of inlet mass flux, inlet quality and branch flow split on the measured parameters for annular inlet flow in two horizontal tee junctions with a horizontal branch having branch to inlet diameter ratios of 0. 5 and 1. 0.