Application of high-speed photography with rapidly changing color to a cold model circulating fluidized bed

A new technique, named `Microprocessor-Controlled Stroboscope High Speed Photography,' has been tested. This instrument uses sequential flashes of different colors, with the frequency controlled by a microprocessor to freeze the motion of individual moving tracer particles. By this means, a series of different color images of moving particles can be recorded on each frame of film. Accordingly, the velocities, accelerations, and trajectories of moving particles can be determined, and circulation patterns can be traced. Tests were carried out with particles of 100 to 500 micrometers diameter in a circulating fluidized bed (CFB), with measured velocities from 0.56 m/s to 10 m/s to demonstrate the usefulness of the new technique.