MEASUREMENT OF FLUCTUATIONS IN MOTION OF PARTICLES IN A DENSE GAS-SOLID SUSPENSION IN VERTICAL PIPE-FLOW

Fluctuating motion of particles in vertical pipe flow of a dense suspe nsion was studied by simultaneous measurements of local density by a f iber optic probe and local mass flow by an electrostatic ball probe. C omplete three-dimensional traverse through the vertical pipe section w as accomplished by a test section which can be turned about its axis. With the availability of a high frequency data system, the instantaneo us particle velocity was determined by dividing the local instantaneou s local density into local instantaneous mass flow. Statistical correl ation gives local average velocity, intensity of particle motion, freq uency of fluctuation, and particle diffusivity. Glass particles of 100 mu m suspended in air were tested. Results show large density and vel ocity fluctuations and large diffusivity at high particle densities.