INFLUENCE OF THE RHEOMETER
GEOMETRY ON THE RHEOLOGICAL PROPERTIES OF INDUSTRIAL LUBRICANTS
Alexandru V. RADULESCU1
Department of Machine Elements and Tribology, University
POLITEHNICA Bucharest, ROMANIA
2 Mechanical Engineering and Research Institute
S. C. ICTCM S.A. Bucharest, ROMANIA
The rheological properties of two transmission
lubricants (75W90 and 75W140), in fresh and used state, were
investigated using shear viscosity rheological measurements. It was
found that the lubricants do not exhibit a yield stress and that,
above a critical shear rate, they exhibit shear-thinning behavior,
well described by the Cross model.
The rheological measurements were performed on a Brookfield
viscometer CAP2000+ equipped with four cone-and-plate geometry, for
a range of temperature between 20 … 70°C, using the viscometer
Peltier system. The experiments have shown that only two geometries
are appropriate for testing the transmission lubricants. Another
important conclusion refers to the influence of the wear degree of
the lubricant on the rheological parameter of the model.
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