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Zur Maßstabsübertragung beim Suspendieren im Rührgefäß
Author(s) -
Kneule Friedrich
Publication year - 1983
Publication title -
chemie ingenieur technik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.365
H-Index - 36
eISSN - 1522-2640
pISSN - 0009-286X
DOI - 10.1002/cite.330550405
Subject(s) - turbulence , homogeneous , mechanics , suspension (topology) , scale (ratio) , volume (thermodynamics) , materials science , shear (geology) , flow (mathematics) , thermodynamics , chemistry , mathematics , physics , composite material , quantum mechanics , homotopy , pure mathematics
Scale‐up of agitated vessels in the case of suspensions . In the scale‐up of agitated vessels a decrease of specific power input ε is recommended in the case of suspensions. Up to now it has been assumed that turbulence is the reason for this decrease. This paper shows that there may also be a contribution due to decreasing wall areas causing less wall shear stresses and moreover a reduction of circulation due to lower cross‐sectional areas per unit volume of the threads of flow. In the case of so‐called „complete suspension” according to the „1‐s criterion”, two mechanisms can be distinguished: On the one hand we have a lifting of solid particles without, and on the other hand such a lifting with formation of bulk accumulations of solids on the bottom of the vessel. In the first case, scale‐up can be done as for a homogeneous distribution of the solid material. The specific power input ε is ∼ μ 0 up to ε ∼ μ −1 with the scale‐up factor μ. In the second case (formation of dense solids clouds) a relationship ε ∼ μ m with m > 0 was found.