Premium
Effect of liquid level and agitator pumping direction on turbulent blend times
Author(s) -
Myers Kevin J.,
Jones Jeremy K.,
Janz Eric E.,
Fasano Julian B.
Publication year - 2014
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.21868
Subject(s) - impeller , agitator , turbulence , materials science , mechanics , flow (mathematics) , axial compressor , liquid flow , physics , thermodynamics , gas compressor
With the impeller placed low in the tank ( C / T = 1/3), turbulent blend times produced by radial‐flow and down‐pumping axial‐flow impellers generally increase slowly with increasing liquid level in shorter batches ( Z / T < 1), but increase dramatically in taller batches ( Z / T > 1). The turbulent blend times produced by up‐pumping axial‐flow impellers increase slowly with increasing liquid level across the entire spectrum of liquid levels that were studied (up to Z / T = 1.75). This can lead to down‐pumping blend times that are twice as long as those with up‐pumping operation. These differences can be explained by differences in the velocity field in the agitated vessel. Further, the down‐pumping mode can produce blend times in tall tanks that are comparable to those of the up‐pumping mode if the down‐pumping impeller is placed high in the batch such that its discharge flow is directed into the bulk of the liquid.