Dense-phase velocity fluctuation in a 2-D fluidized bed

Abstract

This work presents an investigation of the perturbations induced by the bubbles in a 2-D fluidized bed. A combination of Digital Image Analysis (DIA) and Particle Image Velocimetry (PIV) techniques was developed to characterize the dense and bubble phases. The analysis of the mean and the instantaneous fluctuations of the velocity of the dense phase, together with the solid movement around bubbles, allowed for themeasurement of the influence region, distinguishing an upwardmoving dense phase in the nose and thewake of the bubble (drift) and a downward moving dense phase in the sides of the bubble. For an isolated bubble, we measured the drift area within the total influence region and related the size of these regions to the equivalent diameter of the bubble. This work also presents results on the volumetric dissipation of kinetic energy, wherewe concluded that the energy dissipation in the dense phase is proportional to the square of the bubble velocity