Abstract
Spatial distributions of bubbles in gas-liquid two-phase bubbly flow with various sizes of bubbles were obtained by using an image processing system in a vertical pipe. The test section was a 30.8mm I.D. and approximately 10m height. The equivalent sphere bubble diameters were between 2mm and 8mm. The relation between bubble diameter and radial distribution of volume fraction was investigated based on radial profiles of volume fraction of classified bubbles in sizes. It was assumed that radial profiles of volume fraction of gas-liquid two-phase bubbly flow with almost all the same size of bubbles could be estimated from radial profiles of volume fraction of each group of bubbles classified in size in bubbly flow with various sizes of bubbles. Radial profiles of volume fraction were obtained for each classified bubbles with three different steps: 1.0mm, 0.50mm and 0.25mm. As the results, it was clarified that the some radial profiles of volume fraction of each group of bubbles classified in size in bubbly flow with various sizes of bubbles agreed qualitatively with those of bubbly flow with almost all the same size of bubbles and there were some new types of radial profile. Moreover, effects of the step on radial profiles of volume fraction were investigated. It was confirmed that the radial profiles of volume fraction of each classified bubbles in size varied occasionally with the small step as 0.25 mm. The importance of step size was presented.
