Dispersion of Irregular Particles during Free Fall

Abstract

This paper describes an experimental set up to examine the relationship between powder properties on powder flow pattern during filling operation. For this purpose, the free fall velocities of four types of agricultural dusts (i.e. castor sugar, oat, semolina and tea powder) in a rectangular enclosure were captured using a Particle Image Velocimetry (PIV). The result reveals that oat powder portrayed greater cloud dispersion due to its flaky shape and a lower bulk density. The characteristics of oat powder allowed more air to be dragged into the particle stream and forced the particle to be dispersed and suspended in air due to drag force and terminal velocity. The result presented here may facilitate improvements in dust control and measures in powder industries.

Dust Emission Investigation of Agricultural Powdered Materials.

“…The results obtained by weighing of emitted dust amount generated by 2.5 m/s conveying velocity are shown in Figure 5, as a function of the particle size distribution for three different drop heights. It appears from Figure 5 that the mass fraction of emitted tea dust increases when the fall distance is increased, where the results obtained are consistence with findings of past studies [5,7]. However, insufficient supply of tea powder produced less dust emission at Mesh 60 (< 211Pm) for all drop heights compared to Figure 3 and Figure 4.…”

“…The results of the experiment, shows the emission amount increased with increasing impaction and decreased with increasing interparticle binding force [2]. Numerous studies have attempted to explain on air entrainment and dust emission in materials handling operation [3][4][5][6][7][8].…”