Axial interfacial area transport and flow structure development in vertical upward bubbly and slug flow

Abstract

To improve the interfacial area transport equation model in the bubbly to slug transition flow, experiments are performed using the four-sensor conductivity probe for upward bubbly and slug flow in a 25.4 mm ID pipe. A total of 24 flow conditions are measured at 3 different superficial liquid velocities ranging from 0.5 m/s to 2.0 m/s and 8 different void fractions ranging from 0.1 to 0.6. The axial development of flow profiles is analyzed for bubbly flow, bubble-to-slug transition flow, and slug flow. In addition, the velocity effects on fully developed flow structures are also explained and the probe results are verified using the flow visualization. One-dimensional interfacial area transport due to bubble coalescence and disintegration is presented and its dependence on void fraction and velocity are discussed. These data provide one of the few quantitative results of the velocity effect on flow structure development at the same void fraction.