INTERFACIAL PROFILES AND FLOW CHARACTERISTICS IN VERTICAL DOWNWARD GASLIQUID TWO-PHASE PLUG AND FOAM FLOWS

摘要

In order to clarify interfacial profiles and flow characteristics in vertical downward gas-liquid two-phase flow, Semi-Supermultiple-Point-Electrode Probe (SS-PEP) was employed. The SS-PEP consisted of 67 point-electrode probes arranged on a tube diameter and it can provide time-varying phase distribution across the tube. The graphics of interfacial profiles are presented on typical flow patterns briefly and on slug and foam flows in detail. It is pointed out that the plug flow lies in the two regions separated by the foam flow, which was newly found in this study. The interfacial profiles of gas slugs depend strongly on the slip velocity of gas slug to the liquid phase in liquid slug, and two regions of plug flow are classified into the low and high slip velocity groups. Furthermore, some findings are introduced on a characteristic property observed in the pressure gradients and void fraction fluctuations of foam flow.