Experimental and Numerical Investigation of a Three-phase Fluidized Bed, Using Particle Image Velocimetry

Due to the importance of the impacts of spraying a liquid into FCC riser reactors، the hydrodynamic characteristics of risers have been numerically and experimentally investigated. Based on a 3D transient model with Eulerian approach، a cold simulation was carried out in conditions similar to flow in a FCC riser reactor. The governing equations for the phases and an equation based on the kinetic theory of granular flow (KTGF)، as well as the dispersed turbulence model were applied. The governing equations were numerically solved by FVM for all of phases. Besides volume fraction distribution of the phases، solid particle velocity was determined by utilizing a fast digital image capturing system and particle image velocimetry (PIV) technique. In addition، the particle velocity profile in each height of the riser was obtained via image processing and the cross-correlation algorithm. The results of two-phase simulations show that in most axial levels of the riser، there is a parabola-shaped velocity profile so that the particle velocity near the bed walls is lower than that in the central regions. The results of three-phase simulations revealed that the injection of the third phase into the bed leads to phenomenal changes of the flow pattern. Our results based on CFD are in relatively good agreements with the experimental data.