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EVALUATING SHEAR RATES FOR POWER LAW FLUIDS IN MIXER VISCOMETRY
Author(s) -
CASTELLPEREZ M. ELENA,
STEFFE JAMES F.
Publication year - 1990
Publication title -
journal of texture studies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.593
H-Index - 54
eISSN - 1745-4603
pISSN - 0022-4901
DOI - 10.1111/j.1745-4603.1990.tb00493.x
Subject(s) - impeller , viscometer , rotational speed , rheology , materials science , shear rate , power law , viscosity , non newtonian fluid , mechanics , shear (geology) , newtonian fluid , constant (computer programming) , apparent viscosity , composite material , mechanical engineering , engineering , mathematics , physics , computer science , statistics , programming language
Established mixer viscometry methods, the viscosity matching and the slope methods, were evaluated for determining average shear rates when agitating time‐independent, non‐Newtonian fluids. Results indicate that the use of a constant value of the mixer proportionally constant, k ', is not valid for all ranges of fluid rheological properties, system geometry (impeller and cup) and impeller rotational speed. A small impeller‐to‐cup diameter ratio and impeller rotational speeds greater than .33 rev/s (20 rpm) provide the optimum operating parameters for evaluation of k '.