The transition from the fixed to the fluidized state of well-mixed binary-solid mixtures in a liquid upflow

In this work, an investigation of the transition from fixed to fluidized state of initially homogeneous binary-solid mixtures due to an upward liquid flux was carried out. Like for analogous gas systems, it was confirmed that the full transition occurs over a range of fluid velocities, from the initial to the final fluidization velocity. Based on fluid dynamic equilibrium considerations, we proposed a simple model that quantitatively predicts the different bed configurations as a function of fluid velocity. Thanks to the model, all the mixtures were categorized into four regions, which determined their behavior during the transition process. Extensive experimental investigations supported model predictions, offering insights that had not been reported in previous studies.