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

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 the measurement of the influence region, distinguishing an upward moving dense phase in the nose and the wake 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, where we concluded that the energy dissipation in the dense phase is proportional to the square of the bubble velocity.

Experimental techniques have been applied in a 2-D fluidized bed. The size of the influence region generated by a bubble motion in the dense phase has been measured, the drift region within the total influence region has been also measured. Besides, an expression for the relation of volumetric dissipation of kinetic energy and the bubble velocity is presented.Figure optionsDownload as PowerPoint slide