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Title: De-entrainment phenomena on vertical tubes in droplet cross flow

Technical Report ·
OSTI ID:5830338

In this study flow conditions in the upper plenum of a PWR during the reflood stage of a loss-of-coolant accident (LOCA) are simulated using water sprays and a draft-induced wind tunnel. The de-entrainment efficiencies of isolated structures (25.4-, 63.5-, 101.6-mm-dia cylinders and a 76.2-mm square tube) are presented for a variety of air-water droplet cross flow conditions. Since droplet splashing and/or bouncing from the draining liquid film, which forms on the upstream 180/sup 0/ of the cylinder, is not accounted for in classical inertial impaction theory, there is substantial disagreement between measurement and the theory. The isolated tube de-entrainment efficiency is shown to be only weakly dependent on tube diameter, air velocity, droplet mean velocities, and total liquid flow rate for air velocities less than 14 m/s and droplet mass flux rates greater than 2 kg/m/sup 2/ s. The de-entrainment efficiencies of isolated tubes are extrapolated to those of tubes in a multiple tube array, and a predictive relation is presented for the overall de-entrainment efficiency of multiple tube arrays. 21 refs., 28 figs.

Research Organization:
Los Alamos Scientific Lab., NM (USA)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
5830338
Report Number(s):
NUREG/CR-1421; LA-8316-MS; ON: TI85015844
Country of Publication:
United States
Language:
English