1、Designation: D5481 10D5481 13Standard Test Method forMeasuring Apparent Viscosity at High-Temperature andHigh-Shear Rate by Multicell Capillary Viscometer1This standard is issued under the fixed designation D5481; the number immediately following the designation indicates the year oforiginal adoptio
2、n or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONSeveral different configurations of capillary viscometers have been success
3、fully used for measuringthe viscosity of engine oils at the high shear rates and high temperatures that occur in engines. Thistest method covers the use of a single apparatus2 at a single temperature and single shear rate toachieve greater uniformity and improved precision.1. Scope*1.1 This test met
4、hod covers the laboratory determination of high-temperature high-shear (HTHS) viscosity of engine oils at atemperature of 150C150 C using a multicell capillary viscometer containing pressure, temperature, and timing instrumentation.The shear rate for this test method corresponds to an apparent shear
5、 rate at the wall of 1.4 million reciprocal seconds (1.4 106 s1).3 This shear rate has been found to decrease the discrepancy between this test method and other high-temperature high-sheartest methods33 (Test Methods D4683 and D4741) used for engine oil specifications. Viscosities are determined dir
6、ectly fromcalibrations that have been established with Newtonian oils with nominal viscosities from 21.4 mPas to 5 mPa-s at 150C.5.0mPas at 150 C. The precision has only been determined for the viscosity range 1.45 mPas and 5.05 mPas at 150 C for thematerials listed in the precision section.1.2 The
7、values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.2.1 The centiPoise (cP) is a non-SI metric unit of viscosity that is numerically equal to the milliPascal-second(mPa-s).(mPas).1.2.2 Pounds per square inch (psi) is a non-SI unit o
8、f pressure that is approximately equal to 6.895 kPa. These units are providedfor information only in 6.1.1, 7.3, 9.1.2.1, and the tables.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to
9、establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:4D4683 Test Method for MeasuringViscosity of New and Used Engine Oils at High Shear Rate and HighTemperature byTaperedBearing Simulator Vi
10、scometer at 150 CD4741 Test Method for Measuring Viscosity at High Temperature and High Shear Rate by Tapered-Plug ViscometerD6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and LubricantsD6708 Practice for Statistical Assessment and Improvem
11、ent of Expected Agreement Between Two Test Methods that Purportto Measure the Same Property of a Material1 This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.07 on Flow Prop
12、erties.Current edition approved Aug. 1, 2010Oct. 1, 2013. Published September 2010November 2013. Originally approved in 1993. Last previous edition approved in 20042010as D5481D5481 10.04. DOI: 10.1520/D5481-10.10.1520/D5481-13.2 Manning, R. E., and Lloyd, W.A., “Multicell High Temperature High-Shea
13、r Capillary Viscometer,” SAE Paper 861562.Available from Society ofAutomotive Engineers(SAE), 400 Commonwealth Dr., Warrendale, PA 15096-0001, www.sae.org.3 Girshick, F., “Non-Newtonian Fluid Dynamics in High Temperature High Shear Capillary Viscometers,” SAE Paper 922288. Available from Society of
14、AutomotiveEngineers (SAE), 400 Commonwealth Dr., Warrendale, PA 15096-0001, www.sae.org.4 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summar
15、y page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends t
16、hat users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West
17、 Conshohocken, PA 19428-2959. United States13. Terminology3.1 Definitions:3.1.1 apparent shearviscosity, rate nat the wallshear rate at the wall of the capillary calculated for a Newtonian fluid, asfollows:viscosity of a non-Newtonian liquid determined by this test method at a particular shear rateS
18、a 54V/piR3t (1)andwhere:Sa = apparent shear rate at the wall, s1,V = volume, mm3,R = capillary radius, mm, andt = measured flow time, s.shear stress.3.1.1.1 DiscussionThe actual shear rate at the wall will differ for a non-Newtonian fluid.3.1.2 apparent viscositythe determined viscosity obtained by
19、this test method.3.1.2 densitydensity, nmass per unit volume.volume of the test liquid at a given temperature.3.1.2.1 DiscussionIn the SI,SI notation, the unit of density is the kilogram per metre cubed (kg/mcubic metre. However,3); the for practical use, gramper cubic centimetre (g/cm3 ) is often u
20、sed. One kg/mis customarily used and is3 is 10equivalent to3 g/cm103kg/m3.3.1.3 kinematic viscosityviscosity, nthe ratio of the viscosity to the density of the fluid.3.1.3.1 DiscussionKinematic viscosity is a measure of a fluids resistance to flow under the force of gravity. In the SI, the unit of k
21、inematic viscosityis the metre squared per second (m2/s); for practical use, a submultiple (millimetre squared per second, mm2/s) is more convenient.The centistoke (cSt) is 1 mm2/s and is often used.3.1.4 Newtonian oil or fluidliquid, nan oil or fluid that liquid that at a given temperature exhibits
22、 a constant viscosity at allshear rates or shear stresses.3.1.5 non-Newtonian oil or fluidfluid, nan oil or fluidliquid that exhibits a viscosity that varies with changing shear rate orshear stress.3.1.6 shear ratethe spatial gradient of velocity in laminar flow; the derivative of velocity with resp
23、ect to distance in a directionperpendicular velocity gradient in liquid flow in millimetres per second per millimetre (mm/s per mm) resulting from applied shearstress; the System International (SI) unit for shear rate is reciprocal seconds, s1to the direction of flow3.1.6.1 DiscussionThe derived uni
24、t of shear rate is velocity divided by length. With the time in seconds and with consistent units velocity gradientin the Multi-Cell Capillary Viscometer varies across the capillary annulus from a maximum at the wall of the capillary to zero atthe center of the capillary annulus. Assuming a paraboli
25、c flow profile across the capillary, the apparent shear rate at the capillarywall can be calculated as follows:Sa 54V/piR3t (1)ofwhere:Sa = apparent shear rate (at the wall, s1),V = volume of fluid (mm3) passed through the capillary in time t (s), andR = capillary radius (mm).length, shear rate beco
26、mes reciprocal seconds, or s1.Sa is precise for Newtonian liquids which generate a parabolic flow profile but may be approximate for non-Newtonian liquidsthat do not necessarily generate a parabolic flow profile.D5481 1323.1.7 shear stressstress, nforce per area of fluid in the direction of flow.uni
27、t area causing liquid flow over the area whereviscous shear is being caused; in SI, the unit of shear stress is the Pascal (Pa).3.1.7.1 DiscussionIn a capillary viscometer, the significant shear stress is the shear stress at the wall, thatat the wall of the capillary. That is, the totalforce acting
28、on the cross section area of the capillary annulus divided by the inside area of the inside surface of the capillary.capillary through which the liquid flows. The shear stress at the wall does not depend on the fluid properties (that is, nature of theliquid (that is, whether the liquid is Newtonian
29、or non-Newtonian). The SI unit for shear stress is the pascal (Pa). Mathematically,the shear stress at the wall of a capillary viscometer is shear stress at the capillary wall may be calculated as follows:Z 5PR/2L (2)where:Z = shear stress, Pa,Z = shear stress (Pa),P = pressure drop, Pa,P = pressure
30、 drop (in Pa),R = capillary radius, andL = capillary length in consistent units.L = capillary length (in units consistent with R).3.1.8 viscosityviscosity, nthe ratio between of applied shear stress and shear rate at the same location.the resulting rate ofshear.3.1.8.1 DiscussionViscosityIt is somet
31、imes called the coefficient of viscosity, or the dynamic viscosity. Itdynamic or absolute viscosity. Viscosity isa measure of a fluids the resistance to flow. In the SI, flow of the liquid at a given temperature. In SI the unit of viscosity is apascal second (Pas); for practical use a submultiple (m
32、illipascal second, mPa-s) is more convenient. the Pascal second (Pas), oftenconveniently expressed as milliPascal second (mPas), which has the English system equivalent of the centiPoise (cP).3.2 Definitions of Terms Specific to This Standard:3.2.1 calibration oilsthose oils used for establishing th
33、e instruments reference framework of apparent viscosity versuspressure drop from which the apparent viscosities of the test oils are determined.3.2.1.1 DiscussionCalibration oils, which are Newtonian fluids, are available commercially5 or can be blended by the user.3.2.2 test oilany oil for which th
34、e apparent viscosity is to be determined by the test method.3.2.3 viscometric cellthat part of the viscometer comprising all parts which may be wet by the test sample, including exit tube,working capillary, fill tube, pressure/exhaust connection, plug valve, and fill reservoir.4. Summary of Test Met
35、hod4.1 The viscosity of the test oil in any of the viscometric cells is obtained by determining the pressure required to achieve a flowrate corresponding to an apparent shear rate at the wall of 1.4 106 s1. The calibration of each cell is used to determine theviscosity corresponding to the measured
36、pressure.4.2 Each viscometric cell is calibrated by establishing the relationship between pressure and flow rate for a series of Newtonianoils of known viscosity.5. Significance and Use5.1 Viscosity is an important property of fluid lubricants. The viscosity of all fluids varies with temperature. Ma
37、ny commonpetroleum lubricants are non-Newtonian: their viscosity also varies with shear rate. The usefulness of the viscosity of lubricantsis greatest when the viscosity is measured at or near the conditions of shear rate and temperature that the lubricants will experiencein service.5 The sole sourc
38、e of supply known to the committee at this time is Cannon Instrument Co., P.O. Box 16, 2139 High Tech Rd., State College, PA 16804.16803. If you areaware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at
39、a meeting of theresponsible technical committee,1 which you may attend.D5481 1335.2 The conditions of shear rate and temperature of this test method are thought to be representative of those in the bearing ofautomotive engines in severe service.5.3 Many equipment manufacturers and lubricant specific
40、ations require a minimum high-temperature high-shear viscosity at150C150 C and 106 s1. The shear rate in capillary viscometers varies across the radius of the capillary. The apparent shear rateat the wall for this test method is increased to compensate for the variable shear rate.35.4 This test was
41、evaluated in an ASTM cooperative program.66. Apparatus6.1 Multi-Cell Capillary High-Temperature High-Shear (HTHS) Viscometer,5consisting of several viscometer cells in atemperature-controlled block and including means for controlling and measuring temperature and applied pressure and for timingthe f
42、low of a predetermined volume of test oil. Each viscometric cell contains a precision glass capillary and means for adjustingthe test oil volume to the predetermined value.6.1.1 The Multi-Cell Capillary HTHS viscometer has the following typical dimensions and specifications:Diameter of capillary 0.1
43、5 mmLength of capillary 15 to 18 mmLength of capillary 15 mm to 18 mmTemperature control 150 0.1CTemperature control 150 C 0.1 CPressure range 350 kPa to 3500 kPa (50 to 500psi)Pressure control 1 %Sample volume 7 1 mLSample volume 7 mL 1 mL6.1.2 The thermometer for measuring the temperature of the b
44、lock is a preset digital resistance thermometer. The accuracy ofthis thermometer may be checked by means of a special thermowell and calibrated thermometer5 whose accuracy is60.1C60.1 C or better. See manufacturers recommendations for procedure.7. Reagents and Materials7.1 Newtonian Oils,5having nom
45、inal certified viscosities of 21.5 mPas to 7 mPa-s7.0 mPas at 150C.150 C. See Table 1.7.2 Non-Newtonian Reference Sample,57having a certified viscosity at 150C 150 C and 106s1.7.3 Carbon Dioxide or Nitrogen Cylinder, with reducer valve having a maximum pressure of at least 3500 kPa (500 psi).8. Samp
46、ling8.1 A representative sample of test oil, free from suspended solid material and water, is necessary to obtain valid results. Whenthe sample is suspected to contain suspended material, filter with about 10-m filter paper.9. Calibration and Standardization9.1 Calibration:9.1.1 The volume and capil
47、lary diameter of each viscometric cell in the instrument is provided by the manufacturer, and thenominal flow time, to, corresponding to an apparent shear rate at the wall of 1.4 106 s1 is calculated by the manufacturer usingthe following equation:6 Supporting data have been filed at ASTM Internatio
48、nal Headquarters and may be obtained by requesting Research Report RR:D02-1378RR:D02-1767.TABLE 1 Calibration OilsCalibration OilApproximateViscosity at 150 CAApproximate Pressurefor Test Method(mPa-s)(mPas) psi kPaHT22 1.5 190 1310HT39 2.0 225 1500HT39 2.0 225 1550HT75 2.7 290 2000HT150 3.7 375 250
49、0HT150 3.7 375 2590HT240 5.0 480 3300HT240 5.0 480 3310HT390 7.0 645 4500HT390B 7.0 645 4450A Consult the supplier for specific values.B Consult the supplier for use in instruments with pressure limiters of 525 psi.D5481 134to 54V/1.4*106piR3 (3)where symbols are defined as in 3.1.13.1.6.9.1.2 Using a minimum of four Newtonian calibration oils covering the viscosity range from 21.5 mPas to 5 mPa-smPas at150C,150 C, determine the relationship between pressure and flow rate. rate for each
