An experimental study of the settling velocities of single particles in non-Newtonian fluids

New model for single spherical particle settling velocity in power law (visco-inelastic) fluids

“…Also, their expression does not reduce to the expected limiting behavior for Newtonian fluids. Koziol and Glowacki (1988), Reynolds and Jones (1989) and Machac et al (1995), have also reported similar results and correlations. But unfortunately none of these correlations have been tested using independent experimental data.…”

Sedimentation of a cylindrical particle in a Carreau fluid

“…Peden and Luo [27] reported the settling velocity of cylindrical and disk-shaped particles in drilling and fracturing fluids. Reynolds and Jones [28] measured the drag forces on various types of particles in non-Newtonian fluids. They concluded that using a volume-equivalent diameter is most appropriate in correlating their experimental data.…”

Sedimentation of a circular disk in power law fluids

“…Indeed, at Re = 1, the lowest value used in this work, the ratio (C D /C DN ) ranges from 1 to 1.37 as the value of n is de- creased from n = 1 to n = 0.4 thereby suggesting an increase in drag coefficient due to the shear-thinning behavior. It is worthwhile to remark here that the corresponding range of variation of the ratio (C D /C DN ) for a sphere settling in the creeping flow regime is 1 (C D /C DN ) 1.43 thereby suggesting that the results for a sphere and circular disk are not significantly different from each other at low Reynolds numbers, as also observed in experiments [22]. This is also consistent with the identical drag behavior for a sphere and a disk observed in Newtonian fluids, e.g., see Clift et al [4].…”

“…Furthermore, these results relate only to the two values of power law index of 0.42 and 0.6 and the maximum value of the Reynolds number (based on equal volume sphere) is about 50. Reynolds and Jones [22], on the other hand, simply demonstrated that in the creeping (low Reynolds number) flow region, the disk-like and sphere-like marble chips of equal volume settled with comparable terminal velocity. This qualitative inference is also in line with the subsequent experimental findings of Chhabra et al [23] and Rami et al [24].…”

“…Thus, for instance, Peden and Luo [21] and Reynolds and Jones [22] have reported limited results on the free settling velocity of disks and marble chips in power law liquids. Peden and Luo [21] used only two disks with thickness-to-diameter ratio of ∼0.33 (of sphericity values of 0.75 and 0.76) and correlated their results by empirically modifying the Stokes drag by introducing a function of particle sphericity.…”