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Hindered settling of semidilute monodisperse and polydisperse suspensions
Author(s) -
Davis R. H.,
Birdsell K. H.
Publication year - 1988
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690340114
Subject(s) - settling , dispersity , extrapolation , suspension (topology) , particle (ecology) , reynolds number , sedimentation , volume fraction , mechanics , thermodynamics , range (aeronautics) , chemistry , materials science , physics , mathematics , polymer chemistry , sediment , statistics , geology , paleontology , oceanography , homotopy , pure mathematics , turbulence , composite material
Abstract A light‐extinction principle was used to measure the fall speeds of the interfaces that develop during gravity sedimentation of monodisperse, bidisperse, and tridisperse suspensions of noncolloidal particles with small particle Reynolds numbers in the semidilute total particle volume fraction range 0.0003 ⩽ c 0 ⩽ 0.15. For monodisperse suspensions, the hindered settling velocity of the interface at the top of the suspension was found to be well represented by the correlation of Richardson and Zaki, provided that the isolated particle fall speed was chosen by linear extrapolation of the data to c 0 = 0, with 90% confidence intervals on the exponent of n = 5.0 ± 0.1. For dilute monodisperse, bidisperse, and tridisperse suspensions, the hindered settling velocities of the interfaces showed agreement within experimental uncertainty with the theory of Batchelor, which predicts that the settling velocity decreases linearly with increasing particle concentration and which is based upon pairwise particle interactions.