Applicability of the Homogeneous Equilibrium Model (HEM) In Horizontal Pipe, Annulus and Rod Bundle Flows

Abstract

Flow-pattern transitions, void fraction and pressure drop in two-phase flow for horizontal pipes, annuli and rod bundles have been obtained experimentally for air-water system at room temperature and near atmospheric pressure. The test geometries used include a pipe of inner diameter, 5.08 cm, an annulus of outer pipe diameter, 5.08 cm and inner-to-outer diameter ratio, 0.375 and 37-rod bundles of tube diameter, 10.16 cm and element diameter, 1.27 cm. The results were analyzed in terms of phase velocities. Slip ratios ranging from S=1 to S=5 were obtained for the intermittent flow patterns. The limitation boundaries for using the Homogeneous Equilibrium Model (HEM) to analyzing intermittent flows are presented.