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Validation of Solids Suspension Viscosity Measurements Using Computational Fluid Dynamics
Author(s) -
Dasari R. K.,
Berson R. E.
Publication year - 2011
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.201000223
Subject(s) - impeller , suspension (topology) , viscometer , mixing (physics) , viscosity , agitator , slurry , suspended solids , computational fluid dynamics , mechanics , materials science , rheology , dispersion (optics) , chemistry , composite material , engineering , physics , waste management , mathematics , optics , quantum mechanics , homotopy , wastewater , pure mathematics
Accurately measuring the viscosity of a solids suspension requires uniform suspension of the solids in the viscometer cup. In a cup‐and‐impeller viscometer system, solids may settle when the impeller speed is too low, causing viscosity measurements to appear lower than that of a well‐suspended slurry. Pre‐mixing of a solids suspension is typically performed to achieve steady state prior to measurements. Data here shows that the measured viscosity values differ depending on the pre‐mixing speed, indicating that the solids are not properly suspended at all speeds. A commonly used cup‐and‐vane impeller system can be thought of as a mixing tank that should operate above the uniform‐suspension speed (USS), although determining the USS experimentally is rather subjective. Computational fluid dynamics (CFD) is employed here to determine the USS of a pretreated corn stover (PCS) solids suspension and to confirm the experimentally measured USS.