Abstract
Flow behavior of large particle-water two-phase slug flow was observed in a vertical pipe of 30.3mm inside diameter. Large particles with 12.9 and 17.8 mm in mean diameter and density about 2300kg/m3 were used as solid phase. Velocities of solid slug composed of several particles and of solid particles in liquid slug were estimated by proposed correlations of their restricted settling velocities in a pipe. Departure phenomenon of a solid particle from solid slug were also discussed.