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Determination of correlations to predict the minimum agitation speed for complete solid suspension in agitated vessels
Author(s) -
Armenante Piero M.,
Nagamine Ernesto Uehara,
Susanto Jessyca
Publication year - 1998
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.5450760310
Subject(s) - impeller , suspension (topology) , mechanics , diameter ratio , slip factor , flow (mathematics) , materials science , mathematics , physics , homotopy , pure mathematics
Abstract Experiments were conducted to determine the effects of impeller clearance, impeller diameter, and other operating variables on the minimum agitation speed for off‐bottom solid suspension in agitated vessels, N js , for disc turbines (DTs) and flat‐blade turbines (FBTs). Only data for which the impellers produced recirculation flows above and below the impeller (the so‐called “double‐eight” flow pattern) were considered. Regression equations for N js were obtained, in which explicit terms for impeller clearance and vessel diameter‐to‐impeller diameter ratio ( T / D ) were included. Modified Zwietering equations (Zwietering, 1958) were also obtained, in which Zwietering's parameter S was mathematically expressed as a function of vessel diameter‐to‐impeller clearance ratio and T/D ratio. When used together with the correlations of Armenante and Uehara Nagamine (1998) for impellers close to the vessel bottom, the equations presented here can be used to calculate N js for DTs and FBTs for any typical impeller clearance.