ASTM D5481-04
(Test Method)Standard Test Method for Measuring Apparent Viscosity at High-Temperature and High-Shear Rate by Multicell Capillary Viscometer
Standard Test Method for Measuring Apparent Viscosity at High-Temperature and High-Shear Rate by Multicell Capillary Viscometer
SIGNIFICANCE AND USE
Viscosity is an important property of fluid lubricants. The viscosity of all fluids varies with temperature. Many common petroleum lubricants are non-Newtonian: their viscosity also varies with shear rate. The usefulness of the viscosity of lubricants is greatest when the viscosity is measured at or near the conditions of shear rate and temperature that the lubricants will experience in service.
The conditions of shear rate and temperature of this test method are thought to be representative of those in the bearing of automotive engines in severe service.
Many equipment manufacturers and lubricant specifications require a minimum high-temperature high-shear viscosity at 150°C and 106 s−1. The shear rate in capillary viscometers varies across the radius of the capillary. The apparent shear rate at the wall for this test method is increased to compensate for the variable shear rate.3
This test was evaluated in an ASTM cooperative program.6
SCOPE
1.1 This test method covers the laboratory determination of high-temperature high-shear (HTHS) viscosity of engine oils at a temperature of 150°C using a multicell capillary viscometer containing pressure, temperature, and timing instrumentation. The shear rate for this test method corresponds to an apparent shear rate at the wall of 1.4 million reciprocal seconds (1.4 x 106 s-1). This shear rate has been found to decrease the discrepancy between this test method and other high-temperature high-shear test methods3 used for engine oil specifications. Viscosities are determined directly from calibrations that have been established with Newtonian oils with viscosities from 2 to 5 mPa·s at 150°C.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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Designation:D5481–04
Standard Test Method for
Measuring Apparent Viscosity at High-Temperature and
1
High-Shear Rate by Multicell Capillary Viscometer
This standard is issued under the fixed designation D5481; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Severaldifferentconfigurationsofcapillaryviscometershavebeensuccessfullyusedformeasuring
the viscosity of engine oils at the high shear rates and high temperatures that occur in engines. This
2
test method covers the use of a single apparatus at a single temperature and single shear rate to
achieve greater uniformity and improved precision.
1. Scope* D4683 Test Method for Measuring Viscosity of New and
Used Engine Oils at High Shear Rate and High Tempera-
1.1 This test method covers the laboratory determination of
ture by Tapered Bearing Simulator Viscometer at 150 °C
high-temperaturehigh-shear(HTHS)viscosityofengineoilsat
D4741 Test Method for Measuring Viscosity at High Tem-
a temperature of 150°C using a multicell capillary viscometer
peratureandHighShearRatebyTapered-PlugViscometer
containing pressure, temperature, and timing instrumentation.
The shear rate for this test method corresponds to an apparent
3. Terminology
shear rate at the wall of 1.4 million reciprocal seconds
6 −1 3 3.1 Definitions:
(1.4 310 s ). Thisshearratehasbeenfoundtodecreasethe
3.1.1 apparent shear rate at the wall—shear rate at the wall
discrepancy between this test method and other high-
3 of the capillary calculated for a Newtonian fluid, as follows:
temperature high-shear test methods used for engine oil
3
specifications.Viscositiesaredetermineddirectlyfromcalibra-
S 54V/pR t (1)
a
tions that have been established with Newtonian oils with
where:
viscosities from 2 to 5 mPa·s at 150°C.
−1
S = apparent shear rate at the wall, s ,
a
1.2 This standard does not purport to address all of the
3
V = volume, mm ,
safety concerns, if any, associated with its use. It is the
R = capillary radius, mm, and
responsibility of the user of this standard to establish appro-
t = measured flow time, s.
priate safety and health practices and determine the applica-
3.1.1.1 Discussion—The actual shear rate at the wall will
bility of regulatory limitations prior to use.
differ for a non-Newtonian fluid.
3.1.2 apparent viscosity—thedeterminedviscosityobtained
2. Referenced Documents
by this test method.
4
2.1 ASTM Standards:
3.1.3 density—mass per unit volume.
3.1.3.1 Discussion—In the SI, the unit of density is the
1 3
This test method is under the jurisdiction of ASTM Committee D02 on
kilogram per metre cubed (kg/m ); the gram per cubic centi-
3 3 −3 3
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
metre (g/cm ) is often used. One kg/m is 10 g/cm .
D02.07 on Flow Properties.
3.1.4 kinematic viscosity—the ratio of the viscosity to the
Current edition approved May 1, 2004. Published June 2004. Originally
approved in 1993. Last previous edition approved in 2001 as D5481–96 (2001). density of the fluid.
DOI: 10.1520/D5481-04.
3.1.4.1 Discussion—Kinematic viscosity is a measure of a
2
Manning, R. E., and Lloyd, W. A., “Multicell High Temperature High-Shear
fluid’s resistance to flow under the force of gravity. In the SI,
Capillary Viscometer,” SAE Paper 861562. Available from Society of Automotive
the unit of kinematic viscosity is the metre squared per second
Engineers (SAE), 400 Commonwealth Dr., Warrendale, PA 15096-0001.
2
3
Girshick, F., “Non-Newtonian Fluid Dynamics in High Temperature High (m /s); for practical use, a submultiple (millimetre squared per
2
Shear Capillary Viscometers,” SAE Paper 922288. Available from Society of
second, mm /s) is more convenient. The centistoke (cSt) is 1
Automotive Engineers (SAE), 400 Commonwealth Dr., Warrendale, PA 15096-
2
mm /s and is often used.
0001.
4
3.1.5 Newtonian oil or fluid—an oil or fluid that exhibits a
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
constant viscosity at all shear rates or shear stresses.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D5481–04
3.1.6 non-Newtonian oil or fluid—an oil or fluid that exhib- achieve a flow rate corresponding to an apparent shear rate at
6 −1
its a viscosity that varies with
...
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