THE INFLUENCE OF HORIZONTAL INTERNAL BAFFLES ON THE FLOW PATTERN IN DENSE FLUIDIZED-BEDS BY X-RAY-INVESTIGATION

The influence of horizontally placed internals on the physical behavio ur of a dense fluidized bed has been observed using an X-ray technique . The internals were sieve-like baffles with an aperture size two orde rs of magnitude larger than the diameter of the bed particles. Both a freely bubbling bed and single injected bubbles were observed. For the latter, the bubbles were made to emerge from a layer more opaque to X -rays into one more transparent. In this way, the flow pattern around the bubble and the wake could be observed. The results show that the b affles do not influence the mean bubble size or velocity significantly , confirming earlier indirect observations. It is also shown that the wake material is removed from the fluidization bubbles by the baffles. Results are given as statistics for bubble size and rise velocity as a function of the fluidization velocity with and without baffles prese nt, and sequences of X-ray images showing the effect of the baffles. ( C) 1998 Elsevier Science S.A. All rights reserved.