ASTM_E_2975_-_15.pdf

Designation:E297515Standard Test Method forCalibration of Concentric Cylinder Rotational Viscometers1This standard is issued under the fixed designation E2975;the number immediately following the designation indicates the year oforiginal adoption 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.1.Scope1.1 This test method describes the calibration(or perfor-mance validation)of rotational viscometers in which therotational element is immersed in the test fluid under ambienttemperature conditions.It is not intended for cone-and-plate orparallel plate viscometers.1.2 Calibration shall be performed with Newtonian refer-ence materials using experimental conditions,such astemperature,viscosity range and shear rate(rotational speed),as close as practical to those to be used for measurement of testspecimens.1.3 The values stated in SI units are to be regarded asstandard.The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not considered standard.1.3.1 Common viscosity units of Poise(P)are related to theSI units by the equivalency 1 cP=1 mPas.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E473 Terminology Relating to Thermal Analysis and Rhe-ologyE1142 Terminology Relating to Thermophysical PropertiesE1970 Practice for Statistical Treatment of ThermoanalyticalData3.Terminology3.1 DefinitionsSpecific technical terms used in this testmethod are described in Terminologies E473 and E1142includingNewtonian,non-Newtonian,stress,strain,viscometer,viscometry,and viscosity.3.2 Definitions of Terms Specific to This Standard:3.2.1 apparent viscosity(),nviscosity determined by thistest method.3.2.1.1 DiscussionBecause the velocity gradient in thistest method may not be the same at all points of the rotationalelement for non-Newtonian fluids,the result determined maynot be the true viscosity.Therefore,the viscosity determined bythis test method is called the“apparent viscosity.”4.Summary of Test Method4.1 An element is rotated in a Newtonian fluid at a known(or measured)speed.The viscous drag experienced by theimmersed element is measured(or known)as a torque.Viscosity may then be determined from these properties(torque and rotational speed)and the dimensions of therotational element by equations such as Eq 1 and 2.5 9.55 E S (1)S 5rc22 rg2!4rc2rg2L!#(2)where:=viscosity(Pas),=rotational speed(r/min),E=calibration coefficient(dimensionless),=torque(Nm),S=rotational element factor(mm-3)supplied by the appa-ratus vendor,L=length of the cylindrically shaped rotational element(mm),rg=radius of the cylindrically shaped rotational element(m),andrc=radius of the cylindrically shaped container(m).NOTE11 Pa=1 N/m2;1 cP=1 mPas;1 r/min=0.1047 rad/s.4.2 Calibration of a viscometer and its associated rotationalelement may be achieved by comparing the viscosity indicatedby the apparatus with the known viscosity of a calibration fluidas their product using Eq 3,under experimental conditionsused in measuring an unknown fluid:E 5 t o(3)where:t=the viscosity of the calibration fluid(Pas),and1This test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.08 on Rheol-ogy.Current edition approved Sept.1,2015.Published October 2015.Originallyapproved in 2014.Last previous edition approved in 2014 as E2975 14.DOI:10.1520/E2975-15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 o=the viscosity indicated by the apparatus(Pas).5.Significance and Use5.1 This test method may be used to calibrate a rotationalviscometer and its associated rotational element.5.2 The apparent viscosity()of a test specimen may thenbe obtained using Eq 4:5 E o(4)6.Apparatus6.1 Viscometer,Concentric Cylinder RotationalThe es-sential instrumentation required providing the minimum rota-tional viscometer analytical capabilities for this test methodinclude:6.1.1 A drive motor,to apply a rotational displacement tothe specimen at a rate from 0.5 to 60 r/min constant to 60.2%of full scale or alternatively a torque to the specimen constantto 60.2%of full scale.6.1.2 A coupling shaft,or other means to transmit therotational displacement from the motor to the specimen.NOTE2It is convenient to have a mark on the shaft to indica