Settling Velocities in Batch Sedimentation

摘要

The sedimentation of mixtures containing one and two sizes of spherical particles (44 and 62 mu m in diameter) was studied. Radioactive tracing with exp 57 Co was used to measure the settling velocities. The ratio of the settling velocity U of uniformly sized particles to the velocity predicted to Stokes' law U sub 0 was correlated to an expression of the form U/U sub 0 = epsilon/sup alpha /, where epsilon is the liquid volume fraction and alpha is an empirical constant, determined experimentally to be 4.85. No effect of viscosity on the ratio U/U sub 0 was observed as the viscosity of the liquid medium was varied from 1x10 exp -3 to 5x10 exp -3 Pa.s. The settling velocities of particles in a bimodal mixture were fit by the same correlation; the ratio U/U sub 0 was independent of the concentrations of different-sized particles. (ERA citation 08:002674)