| Studies on bubble size, velocity, flow pattern, occurrence frequency and volume fraction are important for modeling and design of fluidized beds. In this research work, experiments were carried out in a 10 cm diameter fluidized bed with a porous plate distributor. The particles used as solid phase include narrow size distribution polyethylene (NPE), wide size distribution polyethylene (WPE) and narrow size distribution sand (NS) particles. Air was the gas phase. A medical X-ray fluoroscopy system (GE MPX-100) was employed to capture the fluidized bed images at superficial gas velocities ranging from 1.5 x Umf to 3.0 x Umf for the three gas-solid systems. The images were video-recorded and used for digitizing and image processing. In order to determine the superficial gas velocities to be used for the imaging experiments, minimum fluidization measurements were also conducted for the three systems. To provide bubble flow information with good statistics, an image processing software package has been developed for analysis of the digitized images captured at 30 frames/s. In total, 12 image data sets were processed. Bubble diameter, vertical and horizontal velocity, occurrence frequency and bubble volume fraction were extracted. (Abstract shortened by UMI.)... |
