A System to Trace Individual Solid Particles in a Fluidized Bed

Abstract

A monolayer-particle fluidized bed is constructed to elucidate the behavior of particles. By using a high-speed video camera, observation and recording of the movement of particles, especially around bubbles were performed. The pictures were saved as data files in a personal computer by applying an image analyzer.
Data files consist of 470 × 370 pixels having 256 grades of brightness for each pixel. Then a program that recognizes each individual particle and searches for its loci from the consequential data files is made by tracing pixels with brightness higher than a certain threshold value. Also, a program for calculating the velocity of each particle is developed. In this program, each picture is divided into 100 blocks and a typical velocity of the particles in the block is calculated by comparing it with that in the next picture. By this typical velocity of the block, each particle can find the position in the next picture. In this manner, the velocity of each particle can be calculated.
The characteristic feature of this system is to be able to trace all the particles continuously without any tracer particle. The applicability of this system to trace the complex behavior of particles around a bubble confirms its effectiveness.