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Wall effect for the fall of spheres in cylindrical tubes at high reynolds number
Author(s) -
Uhlherr P. H. T.,
Chhabra R. P.
Publication year - 1995
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450730615
Subject(s) - reynolds number , spheres , mechanics , settling , aspect ratio (aeronautics) , magnetic reynolds number , physics , diameter ratio , mathematics , reynolds decomposition , reynolds equation , classical mechanics , materials science , thermodynamics , turbulence , optoelectronics , astronomy
New experimental results on the wall effect for sphere motion in cylindrical tubes are presented and discussed for the conditions d/D ≤ 0.9 and Re m ≤ 20000. Extensive comparisons with previous studies have been carried out to evaluate their predictability and to demonstrate the utility of the present results. The wall factor, defined as the ratio of settling velocity in an unbounded medium to that measured in a cylindrical tube, is found to depend on sphere‐to‐tube diameter ratio and on sphere Reynolds number. However, for small values of the Reynolds number ( Re ≤ 0.5), as well for large values ( Re ≥ 1000), the Reynolds number dependence of the wall factor disappears; in these regions, only the dependence on diameter ratio remains.