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Kynch theory and compression zones
Author(s) -
Fitch Bryant
Publication year - 1983
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.690290611
Subject(s) - settling , tangent , discontinuity (linguistics) , geology , mechanics , sedimentation , sediment , mathematics , geotechnical engineering , soil science , geometry , mineralogy , thermodynamics , physics , geomorphology , mathematical analysis
Kynch's theories of sedimentation are reinterpreted, modified, and extended to be valid for batch sedimentation in which a zone of compacting sediment forms at the bottom of the column. The development has several steps: First, it is shown that a concentration discontinuity, any part of whose chord plots above the curve on a Kynch plot of settling flux vs. particle concentration, will be unstable and immediately give rise to a different concentration distribution. From this it is deduced that Kynch characteristics, or loci of constant concentration, must propagate either from the origin of a height vs. time plot, or tangentially from the locus of the compression or suspension‐sediment discontinuity. A Kynch‐like construction is derived to relate the settling rate at the top of the suspension (measured by its subsidence rate) to the concentration arriving at the surface at that time. It makes use of two tangents, one to the settling curve (as in Kynch), and another to the locus of the compression discontinuity. Finally a construction, analagous to that of Talmage and Fitch, is deduced for determining required thickener area.