Experimental study on solids mixing and bubble behavior in a pseudo-2D, freely bubbling, gas-solid fluidized bed using PIV and DIA

Abstract

The hydrodynamics of a freely bubbling, gas-solid fluidized bed has been investigated experimentally with non-invasive measuring techniques in a pseudo-2D column filled with glass beads of 400-600 μm fluidized with air. Particle Image Velocimetry (PIV) combined with Digital Image Analysis (DIA) has been used to determine simultaneously the emulsion phase circulation patterns, bubble hold-up and bubble size and velocity distributions. The combination of DIA with PIV allows correcting for the influence of particle raining through the roof of the bubbles on the time-averaged emulsion phase velocity profiles. The time-averaged emulsion phase circulation patterns have been measured as a function of fluidization velocity. Moreover, with DIA the average bubble diameter and bubble velocity as a function of height and fluidization velocity have been determined and found to correspond reasonably well with literature correlations. The experimental data provides a basis for development and validation of CFD models to describe the solids-mixing in gas-solid fluidized beds