ON THE BUBBLING DYNAMICS OF BINARY MIXTURES OF PARTICLES IN 2D GAS-SOLID FLUIDIZED BEDS

The bubbling behaviour of fluidized beds has been thoroughly investigated in the last decades by means of several techniques, e.g. X-ray, Inductance, Resistance and Impedance based techniques, PIV. In recent years, Digital Image Analysis Techniques have shown their potential for accurate and cost effectively measurements. Most of the work related to bubble behaviour analysis deals with monodispersed particles, while almost all industrial equipment operates with mixtures of particles. Although considerable work has been done in the past with focus on the analysis of the mixing-segregation behaviour and predictions of fluid dynamics regime transitions, a lack of knowledge exists in the analysis of bubbles properties measurements for the case of polydispersed systems. In this work, a Digital Image Analysis technique has been applied to bubbling fluidized beds of binary mixtures of particles, in order to accurately measure bubble diameter, bubble density, bubble velocity, among others. The experiments have been carried out at steady state conditions with binary mixtures of corundum particles, at various inlet gas velocities. A preliminary statistical analysis has been performed to describe bubbling dynamics of bi-dispersed gas-fluidized beds, with the aim to collect valuable data for future development of predictive correlations