SYMPOSIA PAPER Published: 01 January 1978
STP46078S

Oil Viscosity at High Shear Rates Measured by a Floating Journal Bearing

Source

A high shear rate, 1 ×106sec-1, viscometer uses a commercial tool post grinder fitted with a three-bearing internal type spindle to drive a one inch (2.54 cm) diameter journal at 10,400 rpm. A 0.0005 inch (0.00127 cm) thick fluid film between the journal and a floating bearing transfers a torque to the bearing. An oil pump built into the journal minimizes temperature and oil flow problems. Torques measured with Newtonian oils provide a torqueviscosity calibration that is used to convert torques of non-Newtonian oils to viscosities. Two bearings are used; one measures viscosities from 1.6 to 5 cp, the other, 3.4 to 10 cp. Less than one hour is required to measure an oil's viscosity over the range of either bearing at temperatures up to 370°F (188°C). This apparatus measures viscosities at the shear rate and temperatures of critical high shear sections of operating engines and hydraulic systems. The differences between ASTM D 445 kinematic viscosities and viscosities at 1x106sec-1 shear rate were determined for multigraded oils formulated with a number of polymeric viscosity index improvers. At the high shear rate the percent loss of the kinematic viscosity contributed by the polymers increases as temperature decreases.

Author Information

DenHerder, M., J.
Amoco Oil Co.
Harnach, J., W.
Amoco Oil Co.
Wester, D., W.
Amoco Oil Co.
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Details
Developed by Committee: D02
Pages: 79–83
DOI: 10.1520/STP46078S
ISBN-EB: 978-0-8031-6761-2
ISBN-13: 978-0-8031-6697-4