The Diffusion of Solid Particles in a Turbulent Gas Stream

Abstract

<p>An experimental study was performed to measure the diffusion of solid particles in a gas stream flowing turbulently in a 5.5 in. diameter pipe at a Reynolds number of 52800.</p> <p>Glass beads (density 2.55 g/cm 3 ) with a size range 0-60 microns and average particle size of 35 microns were injected into the gas stream. The particle motion was observed by measuring the particle concentrations at various radial and axial positions downstream. A solids feeder and a sampling system were designed for this purpose.</p> <p>A method of analysing the experimental data based on a constant eddy diffusivity of the particles was developed. This analysis indicates that under the conditions studied, the eddy diffusivity of the particles is approximately 60% of that of the gas. The experimental results demonstrate that this model provides a reasonably good approximation to the turbulent diffusion in circular conduits. The results also provide a fairly good picture of the interaction between the fluid and solid particles in turbulent flow.</p> <p> Some future directions for research in this area are also indicated. </p>