Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

The design of bubble column reactors require a comprehensive understanding of the fluid dynamics. The type of gas distributor has a main impact on bubble size distribution and flow regime. With increasing gas flow rate, the interaction of the bubble increases and the dispersion of the bubbles changes. Although these effects play an important role also on the mass transfer in bubble columns, the distance parameters of bubbles in dense swarms has been poorly investigated so far.

This contribution presents an experimental study carried out with ultrafast X-ray CT (UFXCT) on a dense bubbly flow. Experiments were conducted in a bubble column of 10 cm inner diameter and for gas superficial velocities up to 3.5 cms-1. UFXCT allows for non-invasive plane measurement of the phase distribution at different scanning heights of the column. Based on the extracted coordinates of the bubble centers the distances of nearest neighbors of all bubbles were computed. In addition, pair correlation function has been applied to reveal information on the near order of bubbles. The Sauter Mean Diameter was found to have a remarkable influence on the clustering characteristics and the near order of the bubbles.