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Microstructure development in concentrated suspensions in a spinning ball rheometer
Author(s) -
Grillet Anne M.,
Mondy Lisa A.
Publication year - 2005
Publication title -
international journal for numerical methods in fluids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 112
eISSN - 1097-0363
pISSN - 0271-2091
DOI - 10.1002/fld.1046
Subject(s) - rheometer , spinning , microstructure , materials science , rheology , mechanics , ball (mathematics) , composite material , slip (aerodynamics) , torque , particle size , thermodynamics , physics , geometry , mathematics , chemistry
The spinning ball rheometer has been proposed as a method to measure the microstructure effect on the bulk rheological properties of concentrated suspensions. Recent experiments have shown that the measured extra torque on the spinning ball decreases as the radius of the spinning ball becomes comparable to the size of the suspended particle. We have performed a series of three‐dimensional boundary element calculations of the rheometer geometry to probe the microstructure effects that contribute to that apparent slip . We present a series of quasi‐static results based on random initial configurations as well as fully three‐dimensional transient calculations, both of which are compared to the available experimental data. For the two cases, the apparent viscosity decreased as the size of the spinning ball decreased relative to the suspended particle. Comparison of the quasi‐static and transient simulations indicates that the microstructure development is critical even at short times. In the transient calculations, the viscosity was observed to increase substantially relative to the torque based on the random initial configuration. Published in 2005 by John Wiley & Sons, Ltd.