Evaluation of Drag Models for Predicting the Fluidization Behavior of Silver oxide Nanoparticle Agglomerates in a Fluidized Bed

The fluidization characteristics of nanoparticle agglomerates have been experimentally and numerically studied in a fluidized bed. The experimental studies were carried out in a bed containing silver oxide dry powder belonging to group B of Geldart's classification with a primary particle size of 30 nm. Pressure drop measurements using an optical fiber technique allowed the effects of particle loading and inlet gas velocity on the fluidization characteristics of the particles to be determined. Interparticle adhesion forces between silver oxide nanoparticles give rise to the formation of agglomerates with a wide size distribution. Furthermore, a considerable number of bubbles are formed in the bed with agglomerate bubbling fluidization and low bed expansion. Numerical simulations were also performed to evaluate the sensitivity of gas–solid drag models. An Eulerian multiphase model was used with different drag models. A mean particle size of 175 μm was chosen for the numerical simulations, and the results obtained for the minimum fluidization velocity and bed expansion ratio show that the modified Syamlal–O'Brien model provides the closest fit to the experimental data.