The Effect of Sudden Change in Pipe Diameter on Flow Patterns of Air-Water two-Phase Flow in Vertical Pipe (I) Sudden-Contraction Cross-Section

摘要

Flow patterns upstream and downstream of a sudden-contraction cross-section in a vertical straight pipe were presented. By comparing with flow patterns in uniform cross-section vertical tubes, the effect of the sudden change in pipe diameter on flow patterns was analyzed. Flow pattern transition mechanisms were discussed and transition criteria for flow pattern transitions were deduced accordingly using the dimensional analysis.