Simulation of a Pulsating Bed Using Eulerian Approach

A numerical study of the effect of gas pulsation on the flow pattern of solid particles in a two-dimensional gas-solid fluidized bed was conducted using the Eulerian granular kinetic theory. Our simulated bed dynamics agreed well with the experimental work of Koksal and Vural, and with the Discrete Element Method (DEM) model simulations of Tsuji et al. INTRODUCTION Gas-solid fluidized beds are widely used in many industrial processes. One operation in which the gas velocity oscillates analogous to a vibrating bed is called pulsating fluidization. The pulsating fluidized bed was first used to fluidize cohesive particles and served as a method of eliminating slugs and gas channeling, thus improving the quality of fluidization. Koksal and Vural [1] recently applied pulsation to the fluidized beds of coarse particles, and suggested that the size of the bubbles in the fluidized bed can be controlled by the gas pulsation. Their study also revealed that pulsation produced more uniform fluidization with less bed expansion, thereby improving the gas-solid contact in comparison with continuous flow. Wong and Baird’s [2] investigation also showed that pulsation gas flow results in smaller and more uniform bubbles than continuous gas flow. Tsuji et al. [3] developed numerical simulation of pulsating fluidized beds using the Discrete Element Method (DEM). In this work we studied numerical simulations of pulsating fluidized beds using the Eulerian granular kinetic theory model and Fluent 6.1 computational fluid dynamics (CFD) code. Our numerical simulations predicted the dynamics of the bed reasonably well when compared to the Koksal and Vural [1] experimental results and the DEM simulations of Tsuji et al. [3].