Date of Graduation
1996
Document Type
Dissertation/Thesis
Abstract
The objective of this project was to investigate the hydrodynamics of fluidized particles (glass beads, d{dollar}\\sb{lcub}\\rm p{rcub}{dollar} = 1.086 mm, {dollar}\\rho\\sb{lcub}\\rm p{rcub}{dollar} = 2501 kg/m{dollar}\\sp3{dollar}) passing through the liquid spray in a semi-circular spouted fluidized bed and, for the first time, to address the question of how the liquid spray affects the particle velocities and voidage profiles in the spray region of such beds. Computer-based video image processing techniques were utilized in order to measure the axial and radial particle velocities and voidage profiles in the draft tube. Two different particle flow conditions, dilute and relatively concentrated, were used in this work and were obtained by varying the gap between the distributor plate and the bottom of the draft tube. Computer-based video images were obtained using a standard RS-170 video signal (30 frames/sec) from a Pulnix CCD shutter camera. These images were then analyzed, using custom imaging software, to measure particle velocities and voidage profiles in the draft tube region of a semi-circular spouted bed. Calibration techniques were developed in order to test the reliability of the particle velocity and voidage data taken with the software. The particle velocity and voidage profiles obtained in the draft tube at dilute and concentrated particle flow conditions were similar. In addition, the favorable agreement of the solids mass flow rate in the draft tube at different axial locations is an independent test of the consistency of data obtained by particle velocity and voidage imaging software. Visual observation through the flat transparent face of the column showed that at the conditions of atomization used in this work there was no significant effects from the liquid droplets on fluidized particles as compared to the conditions of without spray. This observation was confirmed by experimental results and an overall momentum balance. As a final check of consistency, the particle velocity and voidage profiles in the spout and annulus regions were used to compute the solids mass flow rate in the spout and the annulus using numerical integration. The results show that there is close agreement between the solids mass flow rate in both regions.
Recommended Citation
Saadevandi, Bram A., "The use of imaging techniques to study the hydrodynamics of particle motion in a fluidized bed coating device in the region of the liquid spray." (1996). Graduate Theses, Dissertations, and Problem Reports. 9694.
https://researchrepository.wvu.edu/etd/9694