Effect of Gravity on Axial Development of Phase Distribution Patterns in Bubbly Two-Phase Flow

The axial development of the void fraction profile, interfacial area concentration and Sauter mean bubble diameter of adiabatic nitrogen-water bubbly flows in a 9 mm-diameter pipe were measured using stereo image processing in normal and microgravity conditions. The effect of gravity and flow conditions on the radial distribution of bubbles and the axial development of the two-phase flow parameter is discussed in detail based on the obtained data. By taking into account normalized parameters based on void peak fraction and void peak intensity in the pipe cross-section, the phase distribution patterns were classified into three types: a wall peak, a core peak and an intermediate peak. Phase distribution pattern maps are presented for vertical upward bubbly flows in normal and microgravity conditions.