Longitudinal Voidage Distribution

The voidage distribution model permits the derivation of analytical expressions for the integrated average voidage taken through the whole height, defined as 

The A- and B-phases are shown plotted in Fig. 25 (Chen and Kwauk, 1985), whenever an inflection point exists, for FCC catalyst, A1203 and iron ore. 

As the fluidizing quality of the powder deteriorates from Group A to Group B, however, the range for fast fluidization dwindles, until, for sandy materials, TURBULENT often jumps to TRANSPORT without the intermediate FAST stage. This is shown in Fig. 25 for a titanomagnetite concentrate, which is heavy and comparatively coarse. 

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