Home Books eBooks Journals References & Proceedings Authors, Editors, Reviewers A-Z Product Index Awards
Energy and the Environment, 1999

ISSN:
1-56700-127-0 (Print)

HYDRODYNAMICS OF THE FREEBOARD REGION OF A FLUIDIZED BED WITH SECONDARY AIR INJECTION

Murat Koksal
Mechanical Engineering Department, Dalhousie University, Halifax, Canada

R. S. Zayed
Department of Mechanical Engineering, Dalhousie University, B3J 2X4, Halifax, NS, Canada

Feridun Hamdullahpur
University of Waterloo, Canada

Abstract

Gas and particle flow dynamics in the freeboard region of a bubbling fluidized bed was investigated. The results of the swirling lateral air injection measurements showed that the presence of swirl increased the solid internal circulation and residence time. In the experiments without the secondary air injection, the particles were accelerated in the axial direction reaching a maximum velocity at a certain height in the freeboard due to high drag forces exerted on the particles by the gas puffs emerging from bubbles coalescing near the bed surface. The theoretical part of this study involves a 2-D Eulerian-Eulerian (two-fluid) approach using kinetic theory of granular solids to model the bubbling dense region and the freeboard together.