ASTM D2717-1995(2005) Standard Test Method for Thermal Conductivity of Liquids《液体导热性的标准试验方法》.pdf

1、Designation: D 2717 95 (Reapproved 2005)An American National StandardStandard Test Method forThermal Conductivity of Liquids1This standard is issued under the fixed designation D 2717; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision

2、, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the thermalconductivity of nonmetallic liquids. It is appl

3、icable to liquidsthat are: (1) chemically compatible with borosilicate glass andplatinum; (2) moderately transparent or absorbent to infraredradiation; and (3) have a vapor pressure less than 200 torr at thetemperature of test.1.1.1 Materials that have vapor pressures of up to 345 kPa(50 psia), abso

4、lute can be tested provided that adequatemeasures are taken to repress volatilization of the sample bypressurizing the thermal conductivity cell. The usual safetyprecautions for pressure vessels shall be followed under thesecircumstances.1.2 The values stated in SI units are to be regarded as thesta

5、ndard. The values given in parentheses are for informationonly.1.3 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 applic

6、a-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D86 Test Method for Distillation of Petroleum Products atAtmospheric PressureD 1160 Test Method for Distillation of Petroleum Productsat Reduced PressureD 2887 Test Method for Boiling Range Distribution ofPetr

7、oleum Fractions by Gas ChromatographyD 2893 Test Method for Oxidation Characteristics ofExtreme-Pressure Lubricating Oils3. Terminology3.1 Units:3.1.1 The energy units used in this test method are definedas follows:1 Cal (International Table calorie) = 4.1868 absolute J1 Btu (British thermal unit) =

8、 1055.07 absolute J3.1.2 The units of thermal conductivity commonly used andtheir interconversion factors are shown in Table 1.3.2 For working purposes in this test method, the rounded-off value of 4.19 J/cal is used, as this is adequate for theprecision of the test and also represents the rounded-o

9、ff valueof watt-second per calorie units in Table 1, thus avoiding thedifficulty caused by the dual definition of the calorie.3.3 Symbols:Tf= filament temperature, C,Tb= bath thermostat temperature, C,DT = Tf Tb, C,rf= filament radius, cm,ri= internal radius of tube, cm,ro= external radius of tube,

10、cm,L = effective length of tube, cm,R = resistance of filament, V,I = electric current through filament, A,KL= thermal conductivity of liquid, cal/scmC,KG= thermal conductivity of glass-tube, cal/scmC,A = ln(ri/rf)/2p L,cm1, andB = ln(ro/ri)/2p LKG, sC/cal.4. Summary of Test Method4.1 A thermal cond

11、uctivity cell consisting of a straight,four-lead, platinum resistance thermometer element locatedconcentrically in a long, small-diameter, precision-bore boro-silicate glass tube is calibrated by accurate measurement of the1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum

12、 Products and Lubricants and is the direct responsibility of SubcommitteeD02.11 on Engineering Sciences of High Performance Fluids and Solids.Current edition approved June 1, 2005. Published September 2005. Originallyapproved in 1968. Last previous edition approved in 2000 as D 271795(2000).2For ref

13、erenced 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.TABLE 1 Selected Conversion Factors for Thermal ConductivityTo Conver

14、t From To Multiply Bycal/scmC w/cmC 4.184cal/scmC kcal/hmC 360cal/scmC Btuin./hft2F 2903w/cmC cal/scmC 0.2389w/cmC kcal/hmC 86.00w/cmC Btuin./hft2F 693.7kcal/hmC cal/scmC 0.002778kcal/hmC W/cmC 0.01163kcal/hmC Btuin./hft2F 8.064Btuin./hft2F cal/scmC 0.0003445Btuin./hft2F W/cmC 0.001442Btuin./hft2F k

15、cal/hmC 0.12401Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.cell dimensions and by determination of the temperature-resistance properties of the platinum element.4.2 Thermal conductivity is determined by measurement ofthe temperatu

16、re gradient produced across the liquid sample bya known amount of energy introduced into the cell by electri-cally heating the platinum element.5. Significance and Use5.1 The thermal conductivity of a substance is a measure ofthe ability of that substance to transfer energy as heat in theabsence of

17、mass transport phenomena. It is used in engineeringcalculations that relate to the manner in which a given systemcan react to thermal stresses.6. Apparatus6.1 Thermal Conductivity Cell, consists essentially of a thin,straight platinum filament sealed axially in a borosilicate glasstube. The filament

18、 is held taut by a platinum spring. Two heavygage platinum studs support the filament at either end andpermit the filament itself to serve as the element and a four-leadplatinum resistance thermometer. Details and cell constructionare shown in Fig. 1.6.1.1 A tube of 5.00 6 0.01 mm inside diameter sh

19、all beused for liquids of low viscosity as these may create thermalconvection problems in the 10.47-mm tube.6.2 Temperature Conditioning Bath, capable of maintainingtemperature in the vicinity of the thermal conductivity cellconstant and uniform to within 60.001C at the test tempera-ture.6.3 Resista

20、nce Measuring Device, capable of measuring upto 50 V with a sensitivity of at least 10-4V. A Mueller bridgeassembly with commutator for 4-lead resistance thermometerservice or digital multimeter with equivalent sensitivity and aminimum of six digit resistance resolution with 4-lead mea-surement capa

21、bility are acceptable.6.4 Potential Measuring Device, capable of measuring up to1Vwith a precision of 10-6Vor a potentiometer assembly withsensitivity of at least 1 V or a digital multimeter withequvalent sensitivity, range, and a minimum of six digitresolution is acceptable.6.5 Resistor,1-V, precis

22、ion type, with accuracy of60.0005 % and stability of 60.001 % per year.3,46.6 Platinum Resistance Thermometer 4-lead long stemwith quartz sheath.6.7 Power Supply, 24-V dc.NOTE 1Two 12-V automobile batteries in series have proved satis-factory as a power supply. They should be relatively new and full

23、ycharged.6.8 Power Supply, constant-voltage, for potentiometer.4,56.9 Standard Cell, unsaturated cadmium type, for potenti-ometer.4,66.10 Switches, low thermal emf, knife or rotary.3The sole source of supply of Model 9330/1 known to the committee at this timeis Guildline Instruments, Inc., 103 Comme

24、rce St., Ste. 160, P. O. Box 952590, LakeMary, FL 32795-2590.4If you are aware of alternative suppliers, please provide this information toASTM International Headquarters. Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.5The

25、 sole source of supply of No. 245G-NW-19 known to the committee at thistime is Instrulab, Inc., Dayton, OH.6The sole source of supply of a cell of this type known to the committee at thistime is Epply Laboratory, Inc., Newport, RI.A. Penny Head Stopper standard taper 10/30.B. Gold leads to extend 24

26、 in. beyond PTFE plug. Leads from top and bot-tom contacts to be of equal length. Excess from top leads to be locatedin side tube rather than in the top extension of the cell.C. PTFE plug drilled for wires.D. 9-mm OD borosilicate glass.E. Fill top and side tubes with 350 to 500-cSt silicon oil to th

27、is level.F. Insulate gold wire in top and side tubes with woven glass.G. 10.744 6 0.0127 mm ID precision bore borosilicate glass tubing.H. 0.0584-mm dia platinum wire.I. Use 0.502 mm platinum through glass but add 0.502 mm gold for longleads.J. 0.203-mm diameter platinum.FIG. 1 Details of Thermal Co

28、nductivity CellD 2717 95 (2005)26.11 Silicone Oil, dimethyl, viscosity at 25C of 350 to 500mm2/s (500 cSt).7. Standardization of Apparatus7.1 The thermal conductivity of the cell contents, KL, shallbe expressed in terms of the following equation:DT/I2R! 3 4.19 5 A/KL! 1 B (1)where A and B are essent

29、ially constants that depend on thedimensions of the cell and its materials of construction. If thecell is purchased the values of these constants should becertified by the manufacturer.NOTE 2A, in fact, is a constant depending only upon cell geometry,type of glass and, to a lesser extent, the operat

30、ion of the temperature bathand bath fluid. Within the present recommended accuracy of the method,B can be considered to be a constant.7.2 To determine the absolute values of the cell constants,the various dimensions of the cell are obtained by appropriatemeasurements made during and after the constr

31、uction of thecell. The conductivity of the glass cell body is obtained fromthe manufacturers literature.7.3 An additional relative calibration procedure may beused, with reliable thermal conductivity standards. A standardmaterial, such as dimethyl phthalate (Table 2), is placed in thecell. For a giv

32、en current, DT and the cell resistance aremeasured in the manner described in 8.1. By substituting B,asdetermined in 7.1, and the above-measured values into Eq 1,constant A can be determined with accuracy. Small errors in Bhave little effect on the calculated thermalconductivity. Hence,if exact dime

33、nsions for the calculation of the value of B are notavailable, a rough approximation will suffice in many in-stances.7.4 The temperature-resistance relationship of the cell fila-ment is determined by measurement of its resistance at varioustemperatures with the cell filled with a fluid of high therm

34、alconductivity, such as water (Table 3). To eliminate the effectsof self-heating during this calibration, the apparent resistanceat each temperature selected is measured at several low bridgecurrents. The actual resistance is then obtained by extrapola-tion of the curve of apparent resistance versus

35、 current to zerocurrent.8. Procedure8.1 Fill the cell with the sample until the liquid reaches alevel of about 1 or 2 cm in the sidearm. Place it in thethermostated bath and allow to stand until thermal equilibriumis obtained. Determine equilibrium when the zero-currentresistance of the cell reaches

36、 a constant value. Apply a higher(up to 30 mA) current to the cell and bridge circuit. Measurethe magnitude of this current by monitoring the voltage dropacross a 1-V resistor in series with the bridge. When the cellagain reaches temperature equilibrium as determined by mea-surement of its filament

37、resistance, measure the bath tempera-ture accurately with a platinum resistance thermometer andtake a final reading of cell resistance. Repeat this process atleast three times for varying bridge currents. The results willusually show a trend with time at first. Continue measurementsuntil the results

38、 are seen to be fluctuating about a mean. Takethe final resistance measurements as the mean of readingstaken with normal and reverse commutator settings in orderthat recorded resistances are the resistance of only the activeportion of the cell filament and that the effects of the cell leadsshall be

39、cancelled. Calculate the temperature difference DT asthe temperature difference between the cell wire temperature,determined from the cell resistance, and the temperature of thebath.9. Calculations and Report9.1 Calculate the thermal conductivity of the sample usingEq 2, used in conjunction with app

40、ropriate values of A and B,as follows:KL5 A/4.19DT/I2R! 2 B (2)9.2 Calculate a preliminary value of KLusing each set ofexperimental data collected in the manner described above.Average the last three such values to obtain the final value. Thereported test temperature shall be the arithmetic mean of

41、thebath temperature and the wire temperature determined from thecell resistance.NOTE 3When cgs units are used, the units of KLare cal/scmC. Theconversion factors in Table 1 can be used to calculate units in othercommonly used systems. The use of cgs units followed by conversion ofthe units KLas requ

42、ired is recommended as a matter of convenience onlyas they permit the easy performance of the various calculations involvedTABLE 2 Thermal Conductivity of Dimethyl PhthalateATemperature, CThermal Conductivity,mW/cmCB0 1.50110 1.49120 1.48030 1.46840 1.45650 1.44360 1.43070 1.41780 1.40390 1.389100 1

43、.373120 1.343140 1.310160 1.273180 1.236200 1.199AFrom combined study by Physikalish Technische Bundesanstalt (Braunsch-weig, GDR), the Explosives Research and Development Establishment (WalthamAbbey, England) and Mani and Venart (6th Symposium Thermophysical Proper-ties, ASME, 1973, p. 114).BThe co

44、rrelation equation for the tabulated data is: l = 1.50121.05394 3103t 2.23 3 106t2,(3)where:l = the thermal conductivity, mW/cmC, andt = the temperature, C.TABLE 3 Thermal Conductivity of WaterATemperature, C Thermal Conductivity, J/scm C25 610.7 3 10550 644.2 3 10575 666.3 3 105AJamieson, D. T. and

45、 Tudhope, J. S., “A Simple Device for Measuring theThermal Conductivity of Liquids with Moderate Accuracy,” Journal of the Instituteof Petroleum, JIPEA, Vol 50, 1964, pp. 150153.D 2717 95 (2005)3in the approximate solution of the Callendar equation for conversion ofresistance thermometer readings to

46、 actual temperatures.NOTE 4When testing a liquid at a temperature less than 90 % of itsabsolute 50 % boiling point at one atmosphere, as measured by TestMethods D86, D 1160, D 2887, D 2893, the thermal conductivity datamay be expected to be a nearly linear function of temperature. Specifi-cally, if

47、changes in the function Dl/D T over two successive ranges of100C differ by more than 40 %, the operator should consider recalibra-tion of the apparatus.10. Precision and Bias10.1 Because of the complex nature of the procedure for thedetermination of thermal conductivity and because of theexpensive e

48、quipment involved in the initial set-up of theprocedure, there is not a sufficient number of volunteers topermit a cooperative laboratory program for determining theprecision and bias of the method. If the necessary volunteerscan be obtained, a program will be undertaken at a later date.As a prelimi

49、nary estimate, repeatability appears to be about10 % of the mean of two results by the same operator.11. Keywords11.1 nonmetallic liquids; thermal conductivityASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entir