Flow Regimes of Upward Gas-liquid Two-Phase Flow in a Vertical Pipe with an Axisymmetic Sudden Expansion

Abstract

Experimental study was made on the multi-dimensional behavior of upward air-water two-phase flow through a vertical pipe with an axisymmetric sudden expansion, which is one of the typical multi-dimensional channel geometry. The aims of this study are to clarify the multidimensional behavior of bubbly flow or slug flow affected by sudden expansion channel geometry, and to accumulate the experimental data for two-phase flow analysis, which is applicable to predict the multi-dimensional behavior with appropriate accuracy. The observation using a high-speed video camera was performed to clarify the multi-dimensional dynamic flow behavior with the sudden expansion. It revealed the characteristic phenomena such as gas-slug breakup and bubble deformation and bubble size below and above the sudden expansion point. Furthermore the effect of the sudden expansion channel on the flow regime map can be also described by using these experimental result.