Axial interfacial area transport of vertical bubbly flows

Recently, the concept of the interfacial area transport equation has been proposed to develop the constitutive relation on the interfacial area concentration in relation to the modeling of the interfacial transfer terms in the two-fluid model. Accurate data sets on axial development of local flow parameters such as void fraction, interfacial area concentration, interfacial and liquid velocities and turbulence intensity are indispensable to verify the modeled source and sink terms in the interfacial area transport equation. From this point of view, local flow measurements of vertical upward air–water flows in a round tube with an inner diameter of 50.8 mm were performed at three axial locations of z/D=6.00, 30.3 and 53.5 as well as 15 radial locations from r/R=0–0.95 by using the double-sensor probe and the hotfilm probe. In the experiment, the superficial liquid velocity and the void fraction ranged from 0.491 to 5.00 m/s and from 4.90% to 44.2%, respectively. The flow condition covered extensive region of bubbly flows including finely dispersed bubbly flow as well as bubbly-to-slug transition flow. The combined data from the double-sensor probe and the hotfilm probe give near complete information on the time averaged local hydrodynamic parameters of two-phase flow. This data can be used for the development of reliable constitutive relations which reflect the true transfer mechanisms in two-phase flow.