Study of Structured Flow Pattern and Bubble Characteristics of a Pulsed Fluidized Bed Using Kinetic Theory and Turbulence Model

This work presents simulation results and analysis of the hydrodynamics and flow patterns of a pulsed fluidized bed using Eulerian-Eulerian two fluid modeling approach. The pulsed inflow of gas phase is in a form of sinusoidal function as u₀/u_m = A + B sin(2πft) where four pulsating frequencies of 3, 4, 5, 6 HZ are used. The kinetic theory and Johnson and Jackson Frictional Model for particles motions coupled with k-epsilon Turbulence Model for fluid phase, and Gidaspow’s Drag Model for addressing interactions between two phases are used to close the system. The simulation successfully captured the structured and regular bubble patterns reported in other experimental papers. The hydrodynamics, bubble patterns, bubble sizes are obtained and analyzed for each frequency of inlet flow. The effects of inlet velocity, particle size and diameter on the hydrodynamics, flow patterns are also discussed. Discrete Fast Fourier Transform study is carried out on pressure drop, fluid velocities and volume fraction of a series of specific points in the bed to better understand the fluctuation and structure details of the fluid flow. A map of the structured pattern performance of particles with various density and size are marked on the Geldart’s Chart for type B particles. Two Fluid Modeling results improve the understanding of the chaos and structured properties of the conventional and pulsed fluidization.