Particle-tracking studies for solids motion in a gas fluidized bed
It is known that solids motion plays important roles in heat and mass transfer in fluidized beds. The lack of techniques for systematic, quantitative exploration of the solids velocities has seriously hampered the fundamental understanding of transport processes in a fluidized bed. The present study concerns the development of a technique, based on radioactive particle tracking, to study the solids motion in fluidized beds. The principle, design and fabrication of the facility are described in detail in this dissertation. Data reduction schemes are also presented. The mean velocity distributions of solids, ranging from 0.42 to 0.8 mm, fluidized by air flows, ranging from 1.65 to 4.6 times the minimum fluidizing velocity, are presented. It was found that the patterns of gross solids circulation were heavily dependent on the fluidizing velocity and particles size. Sample measurements of limited range of conditions were also obtained for a bed with a distributor plate smaller than the bed cross section and for a bed with a spherical internal structure. In addition, several exploratory studies were also conducted. Sample results of the Lagrangian auto-correlation and turbulent shear stress of the fluctuating velocities are presented. Furthermore, by superimposing selected sets of the tracer's location data to ''synthesize'' the stratified bed experiments, a picture of the solids mixing was obtained. The results suggest that they are feasible and could be valuable in furthering the understanding of fluidized bed dynamics. 46 refs., figs., tabs.
- Research Organization:
- Illinois Univ., Urbana (USA). Dept. of Mechanical Engineering
- DOE Contract Number:
- FG22-81PC40804
- OSTI ID:
- 6460818
- Report Number(s):
- DOE/PC/40804-T16; ON: DE86003643
- Country of Publication:
- United States
- Language:
- English
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420400* -- Engineering-- Heat Transfer & Fluid Flow
CHEMICAL REACTIONS
COMBUSTION
DESIGN
FABRICATION
FLUIDIZATION
FLUIDIZED BEDS
FLUIDIZED-BED COMBUSTION
FLUIDS
GASES
OXIDATION
PARTICLE TRACKS
PARTICLES
PARTICULATES
THERMOCHEMICAL PROCESSES
VELOCITY