Motions of dispersed beads obtained by particle tracking velocimetry measurements - Part II

Particle tracking velocimetry was successfully used to study the three-dime nsional solids movement of large dispersed beads in a vertical column. For the large beads, overlap was a major limitation, especially at high bead co ncentrations. Thus, an additional image enhancement algorithm for particle decomposition was developed as a preprocessor. The beads experienced high a xial and radial fluctuation values; but, these increases were less than for the fluid phase itself. This is, no doubt, a result of the higher inertia of the beads relative to the fluid. The bead fluctuations are less for the radial component than for the axial component, which is similar to that for the fluid phase. From the results of the histogram analysis, the higher be ad concentrations period provided broader and more scattered distributions except for the initial transport period. Finally, comparisons were possible with the data obtained and predictions from a variety of theoretical appro aches. (C) 2000 Elsevier Science Ltd. All rights reserved.