Effect of Gravity on Axial Development of Gas-Liquid Two-Phase Flows

In pursuit of the development of the interfacial area transport equation, the axial development of void fraction profile, bubble number density, interfacial area concentration and Sauter mean diameter of adiabatic nitrogen-water bubbly flows in a 9 mm-diameter pipe were measured in normal and microgravity environments using stereo image-processing. The flow measurements were performed at four axial locations (axial distance from the inlet normalized by the pipe diameter, z/D = 5.0, 20, 40 and 60) at various flow conditions of superficial gas velocity (0.00823–0.0303 m/s) and superficial liquid velocity (0.147–0.907 m/s). The effect of gravity on the radial distribution of bubbles and the axial development of two-phase flow parameters is discussed in detail based on the measured data and the visual observation.