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Absolute Rheometry in the Brabender Viscograph by Mixer Viscometry Calibration
Author(s) -
Aerts Luc,
Verspaille Marleen
Publication year - 2001
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/1521-379x(200102)53:2<59::aid-star59>3.0.co;2-#
Subject(s) - rheometry , viscometer , calibration , materials science , viscosity , composite material , rheology , mathematics , statistics
The Equivalent Cylinder Principle, as described in the literature, has been applied to the Brabender Viscograph in order to calibrate the instrument from a rheometrical point of view. Based on a calibration with a Newtonian fluid, the typical multi‐pin geometry of the Viscograph is recalculated into a virtual concentric cylinder system. Applying standard concentric cylinder equations, this virtual system is then used for calculation of shear stress and shear rate from torque and rotational speed data. The close match of flow curves of carboxymethyl cellulose solutions and starch pastes proves the validity of the calibration. Data from the Brabender Viscograph, normally expressed as Brabender Units at a given rotational speed, can hence be converted into shear viscosity at a specific shear rate and can hence be compared directly with data from other shear instruments. Since the mixer calibration is only valid in the laminar region, the range of validity for Newtonian fluids has been determined too.