1、Designation: D 5478 09Standard Test Methods forViscosity of Materials by a Falling Needle Viscometer1This standard is issued under the fixed designation D 5478; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These test methods cover the measurement of theviscosity of Newtonian and non-Newtonian liquids. These testmethods are applicab
3、le to liquids having viscosities in therange from 5 3 104to 103Pas (0.5 to 106cP). The shear raterange is dependent upon the needle used and viscosity of theliquid and may vary from 104to 103s1.1.2 The yield stress of liquids having this property may alsobe determined.1.3 These test methods consist
4、of determining liquid vis-cosities of Newtonian and non-Newtonian fluids (clear oropaque) by measuring the steady-state (constant) or terminalvelocities of cylindrical needles as they fall through the testliquid under the influence of gravity. Yield stresses of non-Newtonian liquids may be measured
5、using the same procedure.1.4 The values stated in SI units are to be regarded asstandard.1.5 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 practice
6、s and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E1 Specification for ASTM Liquid-in-Glass ThermometersE 2251 Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision Liquids3. Terminology3.1 Definitions:3.1.1
7、dilatant or shear thickening fluid, nfluid in whichthe apparent viscosity increases with increasing shear rate.3.1.2 Newtonian fluid, nfluid in which the dynamic vis-cosity does not vary with shear rate but only with thetemperature and pressure.3.1.3 Non-Newtonian fluid, nfluid in which the dynamicv
8、iscosity varies with shear rate over at least some shear raterange.3.1.3.1 DiscussionThis viscosity is sometimes referred toas the “apparent viscosity” since it is not a true property of thefluid but a variable depending on the shear rate. The viscosityof most non-Newtonian fluids fits a power law e
9、xpression. Apower law fluid is defined by the following equation:ha5 Kdg/dt!n21(1)where:ha= apparent viscosity, Pas (or dynes/cm2= P), mPas=cP,K = fluid consistency, Pasn(or dynesn/cm2),dg/dt = shear rate or velocity gradient, 1/s, andn = flow behavior index, dimensionless.3.1.4 pseudoplastic or she
10、ar thinning fluid, nfluid inwhich the apparent viscosity decreases with increasing shearrate.3.1.5 viscosity, nthe ratio between an applied shear stressto the resulting shear rate (velocity gradient) is defined as thedynamic viscosity. It is a measure of the resistance to flow ofa fluid.3.1.5.1 Disc
11、ussionIn the SI unit system, the units ofviscosity are Pas. One mPas is equal to one centipoise (cP).3.1.6 yield stress, nsome fluids when subjected to a shearstress behave as deformable solids until a certain critical shearstress (yield stress or yield value) is reached after which theybehave as fl
12、uids.3.1.6.1 DiscussionExamples of such fluids include manypaints and pigment pastes and certain food materials such asketchup.4. Summary of Test Methods4.1 Test Method A consists of determining the viscosity ofNewtonian liquids.1These test methods are under the jurisdiction of ASTM Committee D01 on
13、Paint and Related Coatings, Materials, and Applications and are the directresponsibility of Subcommittee D01.24 on Physical Properties of Liquid Paints Newtonian fluid; non-Newtonian fluid; rheological property; rheometer; viscometer;viscosity; yield stressSUMMARY OF CHANGESCommittee D01 has identif
14、ied the location of selected changes to this standard since the last issue(D 5478 - 98 (2003) that may impact the use of this standard. (Approved February 1, 2009.)(1) Definitions are now in the correct form.(2) Several typographical errors have been corrected.(3) Reference has been made to Specific
15、ation E 2251, Speci-fication for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids.(4) SI units have become standard for the methods.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Use
16、rs of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every
17、 five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technic
18、al committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D5478095
