The prediction of the minimum fluidization velocity of beds of Geldart’s group B particles confinedin a packed bed of coarse spheres can be achieved by extending to this peculiar type of systemsthe theory developed for modelling the behaviour of segregating beds of simultaneously fluidizedsolids.The approach is based on separate force balances on the fluid and the fine solids, capable toaccount for the peculiar nature of solid-solid interaction in a confined fluidized bed. Its validation isfulfilled by an extended investigation conducted in two columns (5 and 10 cm OD) packed with afixed bed of 4.1 mm lead shots or 11 mm glass beads. The effect of particle size on the fluidizationregime is investigated by comparing the results provided by experiments in which various cuts ofglass ballotini, ranging from 100 to nearly 600 μm, are fluidized in two packings of fixed spheres;possible differences of behaviour due to particle density are analysed by series of experimentsemploying particles of ceramics, zirconium oxide, steel and bronze of the same diameter.The results obtained confirm the effectiveness of the approach followed, in which an important roleis played by the indirect interaction between the two solid phases.
Extension of the model of binary fluidization to beds confined in a packing of coarse spheres
Girimonte, Rossella
;Formisani, Brunello.
2016-01-01
Abstract
The prediction of the minimum fluidization velocity of beds of Geldart’s group B particles confinedin a packed bed of coarse spheres can be achieved by extending to this peculiar type of systemsthe theory developed for modelling the behaviour of segregating beds of simultaneously fluidizedsolids.The approach is based on separate force balances on the fluid and the fine solids, capable toaccount for the peculiar nature of solid-solid interaction in a confined fluidized bed. Its validation isfulfilled by an extended investigation conducted in two columns (5 and 10 cm OD) packed with afixed bed of 4.1 mm lead shots or 11 mm glass beads. The effect of particle size on the fluidizationregime is investigated by comparing the results provided by experiments in which various cuts ofglass ballotini, ranging from 100 to nearly 600 μm, are fluidized in two packings of fixed spheres;possible differences of behaviour due to particle density are analysed by series of experimentsemploying particles of ceramics, zirconium oxide, steel and bronze of the same diameter.The results obtained confirm the effectiveness of the approach followed, in which an important roleis played by the indirect interaction between the two solid phases.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
