Abstract
Flow configurations of large particle-water two-phase flows in a vertical pipe of 30.3mm I. D. were observed and their flow patterns were classified into sparsely dispersed flow, cluster flow, bunch flow, slug flow and denselydispersed flow. Flow regime maps were presented for large particles of 8.12, 12.9, 17.8 and 24.8mm in mean diameter. The analogy of flow patterns between gas-liquid two-phase flow and liquid-solid two-phase flow was discussed.