1、Designation: D2501 11Standard Test Method forCalculation of Viscosity-Gravity Constant (VGC) ofPetroleum Oils1This standard is issued under the fixed designation D2501; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st revision. 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 This test method covers the calculation of the viscosity-gravity constant (VGC) of petroleum oils2having viscosities in
3、excess of 5.5 mm2/s at 40C (104F) and in excess of 0.8mm2/s at 100C (212F).1.2 Annex A1 describes a method for calculating the VGCfrom Saybolt (SUS) viscosity and relative density.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstand
4、ard.1.3.1 The SI unit of kinematic viscosity is mm2/s.1.3.2 ExceptionFahrenheit temperature units are used inthis practice because they are accepted by industry for the typeof legacy conversions described in this practice.1.4 This standard does not purport to address all of thesafety concerns, if an
5、y, 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:3D287 Test Method for API Gravity of Crude Petroleu
6、m andPetroleum Products (Hydrometer Method)D445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids (and Calculation of Dynamic Viscos-ity)D1298 Test Method for Density, Relative Density (SpecificGravity), or API Gravity of Crude Petroleum and LiquidPetroleum Products by Hydrometer
7、MethodD2140 Practice for Calculating Carbon-Type Compositionof Insulating Oils of Petroleum OriginD4052 Test Method for Density, Relative Density, and APIGravity of Liquids by Digital Density Meter3. Summary of Test Method3.1 The kinematic viscosity at 40C (104F) and the densityat 15C of the oil are
8、 determined. If the oil is extremelyviscous, or if it is otherwise inconvenient to determine theviscosity at 40C, the kinematic viscosity at 100C (212F) canbe used. The viscosity-gravity constant is calculated from themeasured physical properties using the appropriate equation.4. Significance and Us
9、e4.1 The viscosity-gravity constant (VGC) is a useful func-tion for the approximate characterization of the viscous frac-tions of petroleum.2It is relatively insensitive to molecularweight and is related to a fluids composition as expressed interms of certain structural elements. Values of VGC near
10、0.800indicate samples of paraffinic character, while values close to1.00 indicate a preponderance of aromatic structures. Likeother indicators of hydrocarbon composition, the VGC shouldnot be indiscriminately applied to residual oils, asphalticmaterials, or samples containing appreciable quantities
11、ofnonhydrocarbons.5. Measurement of Physical Properties5.1 Preferably, determine the kinematic viscosity at 40C asdescribed in Test Method D445. However, if the sample isextremely viscous or if it is otherwise inconvenient to measurethe viscosity at 40C, the viscosity at 100C may be deter-mined.5.2
12、Determine the density at 15C in accordance with TestMethod D1298 or Test Method D4052. Equivalent results canbe obtained by determining API Gravity at 60F (15.56C) inaccordance with Test Method D287, and converting the resultto density at 15C by means of Table 3 of the PetroleumMeasurement Tables (A
13、merican Edition).4NOTE 1If it is necessary to convert a result obtained using the digital1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04.0K on Correlative Methods.Current edition approved Oct
14、. 1, 2011. Published November 2011. Originallyapproved in 1966. Last previous edition approved in 2005 as D250191(2005).DOI: 10.1520/D2501-11.2Coats, H. B., and Hill, J. B., Industrial and Engineering Chemistry, Vol 20,1928, p. 641.3For referenced ASTM standards, visit the ASTM website, www.astm.org
15、, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Published jointly by, and available from, ASTM Headquarters and EnergyInstitute, 61 New Cavendish St., London W1M 8AP. Companion
16、 volumestheBritish Edition and the Metric Editionare also available. These tables supersedeall other similar tables previously published by either of these societies and theNational Bureau of Standards Circular C-410 and the supplement to Circular C-410.1*A Summary of Changes section appears at the
17、end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.density meter to a density at another temperature, the Petroleum Measure-ment Tables can be used only if the glass expansion factor has beenexcluded.6. Calculation o
18、f Viscosity-Gravity Constant6.1 From Kinematic Viscosity at 40C and Density at15CUse the following equation to calculate the VGC fromthe measured properties:VGC 5G 2 0.0664 2 0.1154 LogV 2 5.5!0.94 2 0.109 LogV 2 5.5!(1)where:G = density at 15C, g/mL, andV = kinematic viscosity at 40C, mm2/s.6.2 Fro
19、m Kinematic Viscosity at 100C and Density at15CUse the following equation to calculate the VGC:VGC 5G 2 0.108 2 0.1255 LogV8 2 0.8!0.90 2 0.097 LogV8 2 0.8!(2)where:G = density at 15C, g/mL, andV8 = kinematic viscosity at 100C, mm2/s.7. Report7.1 Report the calculated VGC to the nearest .002 unit.7.
20、2 If the viscosity at 100C was used for the calculation,state this in the report.8. Precision and Bias8.1 The calculation of viscosity-gravity constant from kine-matic viscosity at 40C and density at 15C is exact. Precisionlimits are not assigned to this calculation.8.2 The precision of the calculat
21、ed VGC is dependent onlyon the precision of the original determinations of viscosity anddensity. Those precision statements are found in their respec-tive test methods. The precision can be calculated as follows:8.2.1 For viscosity measured at 40C,rY510.94 2 0.109 log10V 2 5.5!(3)rG21 rV20.00224 Y 2
22、 1.059!2V 2 5.5!2where:rY= precision of the VGC,rG= precision of the gravity from D287,rV= precision of the viscosity from D445,V = measured viscosity, andY = VGC.8.2.2 For viscosity measured at 100C,rY510.90 2 0.097 log10V 2 0.8!(4)rG21 rV20.00177Y 2 1.294!2V 2 0.8!28.3 The VGC calculated from the
23、viscosity at 100C candiffer slightly from that calculated from the viscosity at 40C.A statistical evaluation of VGC data derived from equivalentviscosities at both 100F and 210F suggests that in the rangefrom about 0.80 to 0.95 VGC, the expected average differencewill be approximately 0.003 units. W
24、henever possible, it ispreferable to determine the VGC using Eq 1.8.4 BiasThe procedure in Test Method D2501 for calcu-lation of viscosity-gravity constant has no bias because thevalue of viscosity-gravity constant can be defined only in termsof a test method.8.5 The term viscosity-gravity constant
25、is also used in TestMethod D2140, for determining carbon-type composition ofinsulating oils of petroleum origin. The equations used aredifferent from those in this test method; the bias between thetwo test methods is unknown.9. Keywords9.1 aromatic; density; kinematic viscosity; paraffinicANNEX(Mand
26、atory Information)A1. CALCULATION OF VISCOSITY-GRAVITY CONSTANT FROM SAYBOLT VISCOSITY AND RELATIVE DENSITY(SPECIFIC GRAVITY)A1.1 The calculation of viscosity-gravity constant (VGC)can also be calculated from viscosity in units of Sayboltseconds universal (SUS) and relative density (specific gravity
27、).A1.2 From Saybolt Viscosity at 100F and RelativeDensity (Specific Gravity) 60/60FA1.2.1 Use the following equation to calculate the VGCfrom the measured properties:VGC 510G 2 1.0752 log V 2 38!10 2 log V 2 38!(A1.1)where:G = relative density (specific gravity) at 60/60F, andV = Saybolt Universal v
28、iscosity at 100F.A1.3 From Saybolt Viscosity at 210F and RelativeDensity (Specific Gravity) 60/60FA1.3.1 Use the following equation to calculate the VGC:VGC 5G 2 0.1244 logV12 31!0.9255 2 0.0979 log V12 31!2 0.0839 (A1.2)where:G = relative density (specific gravity) at 60/60F, andV1= Saybolt Univers
29、al viscosity at 210F.A1.4 The viscosity-gravity constant calculated from theD2501 112Saybolt viscosity at 210F can differ slightly from that calcu-lated from the 100F viscosity. A statistical evaluation of VGCdata derived from both the 100F and 210F viscositiessuggests that in the range from about 0
30、.80 to 0.5 VGC, theexpected average difference will be approximately 0.003 units.Whenever possible, it is preferable to determine the VGC usingEq A1.1.APPENDIXX1. REVISION HISTORYX1.1 This current revision includes a change in Eq 1 andEq 2 in Section 6, Calculation of Viscosity-Gravity Constant.X1.1
31、.1 During a revision change from D2501-87 andD2501-91 there was a change in units from SUS (SayboltUniversal Seconds) to the SI unit of viscosity mm2/s (cSt). Thisunit change necessitated a modification of the Scope (1.1) from“in excess of 40 Saybolt Universal Seconds (SUS) at 100F(37.79C)” to “in e
32、xcess of 4 cSt. = 4 3 106m2/s at 40C(104F).” This change created a mathematical error of trying totake the log of a negative number in Eq 1 (in Section 6,Calculation of Viscosity-Gravity Constant) for V (KinematicViscosities) less than 5.5 cSt (mm2/s) and the Scope value inexcess of 4 cSt. (mm2/s).
33、Consensus input to this discrepancywas to change the Scope from “in excess of 4 cSt. = 4 3 106m2/s at 40C” to “5.5 mm2/s at 40C (104F) and in excess of0.8 mm2/s at 100C (212F).” This change was made in theD2501-11 revision.X1.2 Expected Average Differences in Section 8.3X1.2.1 Section 8.3 (Precision
34、 and Bias) discusses the “sta-tistical evaluation of VGC data derived from equivalent vis-cosities at both 100F and 210F suggests that in the rangefrom about 0.80 to 0.95 VGC, the expected average differencewill be approximately 0.003 units.” Because no evaluation hasbeen performed in SI units, the
35、retention of the English units(F) is retained.SUMMARY OF CHANGESSubcommittee D02.04 has identified the location of selected changes to this standard since the last issue(D250191(2005) that may impact the use of this standard.(1) Changed units of measurement of kinematic viscosity to SIunits.(2) Adde
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39、e 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D2501 113
