Study on flow characteristics in gas-molten metal mixture pool

As part of basic research on the flow characteristics of a two-phase mixtur e pool under severe accident of fast breeder reactor (FBR), visualization a nd measurement of nitrogen gas-molten lead/bismuth two-phase flow in a rect angular pool were performed by using the neutron radiography technique. Mea surements of drag coefficient of a single bubble and bubble shape regime sh owed that the relationship between the shape, size and the rising velocity of a single isolated nitrogen bubble in the molten lead/bismuth was not muc h different from that for an ordinary one. Appropriate correlation for drif t velocity and drag coefficient between phases were recommended based on th e drift flux correlation of measured pool void fraction. One- and two-dimen sional analyses were performed by using a next generation computational cod e for safety analysis of severe accident of FBRs, SIMMER-III with various d rag coefficient models. It was revealed that Kataoka-Ishii's equation was s uitable basically for estimation of drift velocity, namely, drag force betw een phases. (C) 2000 Elsevier Science S.A. All rights reserved.