Mechanistic Prediction of Bubble Properties in Freely-Bubbling Fluidised Beds

Abstract

The approach developed by Nguyen et al.(1975) for predicting bubble behaviour in beds of Geldart’s (1973) Group B particles has been modified to enable application to beds of larger scale. The predictions are generally in agreement with the measurements of Werther (1974), but some discrepancy arises from non-uniform bubble formation caused by solids circulation. The model predicts that the size and spatial distribution of bubbles at any level above the distributor is dependent on the bed depth above that level. Davidson and Harrison’s (1963) expression for bubble rise velocity in freely-bubbling beds fortuitously gives a good estimate for the overall mean velocity of interacting and coalescing bubbles.