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Measurement of the Flow Behaviour of Aerated and Fluidised Powders using a rotating viscometer
Author(s) -
Hobbel Erik F.,
Scarlett Brian
Publication year - 1985
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.19850020128
Subject(s) - viscometer , cylinder , mechanics , rheology , consistency (knowledge bases) , flow (mathematics) , materials science , newtonian fluid , viscosity , angular velocity , thermodynamics , chemistry , composite material , classical mechanics , physics , mathematics , geometry
The rheological behaviour of a fluidised bed of alumina powder was determined using a specially designed form of rotating viscometer. Several different geometries of the inner and outer cylinder were tested. In the machine the two cylinders can be rotated independently, in either direction, which enables both their relative velocity and absolute velocity to be varied. Thus, the torque on the inner cylinder, strain‐rate and the absolute velocity have been chosen as the consistency variables. Some examples of the derived consistency surface are given. The characteristics of these surfaces could be explained by assuming different states of structure, to which a certain mobility can be ascribed. It is proposed that any state of structure which can exist in the bed is an intermediate of two extremes the first being the immobile state which is elastic and has a yield value and the second being the dynamic state which behaves like a Newtonian fluid.