1、Designation: C 1044 07Standard Practice forUsing a Guarded-Hot-Plate Apparatus or Thin-HeaterApparatus in the Single-Sided Mode1This standard is issued under the fixed designation C 1044; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, 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 practice covers the determination of the steady-state heat flow through the meter section of a
3、specimen whena guarded-hot-plate apparatus or thin-heater apparatus is usedin the single-sided mode of operation.1.2 This practice provides a supplemental procedure for usein conjunction with either Test Method C 177 or C 1114 fortesting a single specimen. This practice is limited to only thesingle-
4、sided mode of operation, and, in all other particulars, therequirements of either Test Method C 177 or C 1114 apply.NOTE 1Test Methods C 177 and C 1114 describe the use of theguarded-hot-plate and thin-heater apparatus, respectively, for determiningsteady-state heat flux and thermal transmission pro
5、perties of flat-slabspecimens. In principle, these methods cover both the double- andsingle-sided mode of operation, and at present, do not distinguish betweenthe accuracies for the two modes of operation. When appropriate, thermaltransmission properties shall be calculated in accordance with Practi
6、ceC 1045.1.3 This practice requires that the cold plates of the appa-ratus have independent temperature controls. For the single-sided mode of operation, a (single) specimen is placed betweenthe hot plate and the cold plate. Auxiliary thermal insulation, ifneeded, is placed between the hot plate and
7、 the auxiliary coldplate. The auxiliary cold plate and the hot plate are maintainedat essentially the same temperature. Ideally, the heat flow fromthe meter plate is assumed to flow only through the specimen,so that the thermal transmission properties correspond only tothe specimen.NOTE 2The double-
8、sided mode of operation requires similar speci-mens placed on either side of the hot plate. The cold plates that contact theouter surfaces of these specimens are maintained at essentially the sametemperature. The electric power supplied to the meter plate is assumed toresult in equal heat flow throu
9、gh the meter section of each specimen, sothat the thermal transmission properties correspond to an average for thetwo specimens.1.4 This practice does not preclude the use of a guarded-hot-plate apparatus in which the auxiliary cold plate may beeither larger or smaller in lateral dimensions than eit
10、her the testspecimen or the cold plate.NOTE 3Most guarded-hot-plate apparatus are designed for thedouble-sided mode of operation (1).2Consequently, the cold plate and theauxiliary cold plate are the same size and the specimen and the auxiliaryinsulation will have the same lateral dimensions, althoug
11、h the thicknessmay be different. Some guarded-hot-plate apparatus, however, are de-signed specifically for testing only a single specimen that may be eitherlarger or smaller in lateral dimensions than that auxiliary insulation or theauxiliary cold plate.1.5 This practice can be used for both low- an
12、d high-temperature conditions.1.6 This practice shall not be used when operating anapparatus in a double-sided mode of operation with a knownand unknown specimen, that is, with the two cold plates atsimilar temperatures so that the temperature differences acrossthe known and unknown specimens are si
13、milar.1.7 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. Refere
14、nced Documents2.1 ASTM Standards:C 168 Terminology Relating to Thermal Insulation3C 177 Test Method for Steady-State Heat Flux Measure-ments and Thermal Transmission Properties by Means ofthe Guarded-Hot-Plate Apparatus3C 518 Test Method for Steady-State Thermal TransmissionProperties by Means of th
15、e Heat-Flow Meter Apparatus3C 1045 Practice for Calculating Thermal TransmissionProperties Under Steady-State Conditions31This practice is under the jurisdiction of ASTM Committee C16 on ThermalInsulation and is the direct responsibility of Subcommittee C16.30 on ThermalMeasurement.Current edition a
16、pproved Sept. 1, 2007. Published September 2007. Originallyapproved in 1985. Last previous edition approved in 1998 as C 1044 98(2003).2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards, visit the ASTM website, www.astm.org,
17、 orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.C 1114 Test Met
18、hod for Steady-State Thermal TransmissionProperties by Means of the Thin-Heater Apparatus33. Terminology3.1 DefinitionsFor definitions of terms used in this prac-tice, refer to Terminology C 168. For definitions of termsrelating to the guarded-hot-plate apparatus or thin-heater ap-paratus refer to T
19、est Methods C 177 or C 1114, respectively,3.2 Definitions of Terms Specific to This Standard:3.2.1 auxiliary cold plate, nthe plate that provides anisothermal boundary at the outside surface of the auxiliaryinsulation.3.2.2 auxiliary insulation, nthermal insulation used inplace of a second test spec
20、imen, when the single-sided mode ofoperation is used (syn. dummy specimen).3.2.3 cold plate, nthe plate that provides an isothermalboundary at the cold surface of the specimen.3.2.4 double-sided mode, noperation of the apparatus,such that the heat input to the meter plate flows equally throughtwo sp
21、ecimens, each specimen placed on either side of the hotplate (see also single-sided mode).3.2.5 gap, nseparation between the meter plate and guardplate, usually filled with a gas or thermal insulation.3.2.6 guard plate, nthe outer (rectangular or circular) ringof the guarded hot plate, that encompas
22、ses the meter plate andpromotes one-dimensional heat flow normal to the meter plate.3.2.7 guarded hot plate, nan assembly, consisting of ameter plate and a co-planar, concentric guard plate, thatprovides the heat input to the specimen(s).3.2.8 meter plate, nthe inner (rectangular or circular)plate o
23、f the guarded hot plate, that provides the heat input tothe meter section of the specimen(s).3.2.9 meter section, nthe portion of the specimen (orauxiliary insulation) through which the heat input to the meterplate flows under ideal guarding conditions.3.2.10 single-sided mode, noperation of the app
24、aratussuch that essentially all of the heat input to the meter plateflows through a specimen placed on one side of the hot plate(see also double-sided mode).3.2.11 thin heater, nan assembly, consisting of a unparti-tioned thin-screen heater or thin-foil, that provides the heatinput to the specimen(s
25、).3.3 SymbolsThe symbols used in this practice have thefollowing significance. The prime (8) denotes quantities asso-ciated with the auxiliary insulation used to control heat fromthe other side of the hot plate.3.3.1 Ametre area of hot plate, m2.3.3.2 C8thermal conductance of auxiliary insulation,W/
26、(m2 K).3.3.3 Qheat flow through meter section of specimen, W.3.3.4 Q8heat flow through meter section of auxiliaryinsulation, W.3.3.5 Qmpower input to meter plate, W.3.3.6 Tcsurface temperature of cold plate, K.3.3.7 T8csurface temperature of auxiliary cold plate, K.3.3.8 Thsurface temperature of hot
27、 plate in contact withspecimen, K.3.3.9 T8hsurface temperature of hot plate in contact withauxiliary insulation, K.4. Significance and Use4.1 This practice provides a procedure for operating theapparatus so that the heat flow, Q8, through the meter section ofthe auxiliary insulation is small; determ
28、ining Q8; and, calcu-lating the heat flow, Q, through the meter section of thespecimen.4.2 This practice requires that the apparatus have indepen-dent temperature controls in order to operate the cold plate andauxiliary cold plate at different temperatures. In the single-sides mode, the apparatus is
29、 operated with the temperature ofthe auxiliary cold plate maintained, as close as possible, to thetemperature of the side of the hot plate adjacent to the auxiliaryinsulation.NOTE 4Ideally, if the temperature difference across the auxiliaryinsulation is zero and there are no edge heat losses or gain
30、s, all of thepower input to the meter plate will flow through the specimen. In practice,a small correction is made for heat flow, Q8, through the auxiliaryinsulation.4.3 The thermal conductance, C8, of the auxiliary insulationmust be determined from one or more separate tests usingeither Test Method
31、 C 177, C 1114, or as indicated in 5.4. Thevalues of C8 should be checked periodically, particularly ifduring regular testing it is not possible to keep the temperaturedrop across the auxiliary insulation less than 1 % of thetemperature drop across the test specimen.4.4 This practice can be used whe
32、n it is desirable todetermine the thermal properties of a single specimen. Forexample, the thermal properties of a single specimen are usedto calibrate a heat-flow-meter apparatus for Test MethodC 518. In other cases, there may be only one specimenavailable.5. Procedure for Single-Sided Mode of Oper
33、ation5.1 Refer to Fig. 1 for a schematic diagram of the single-sided mode of operation of the guarded-hot-plate apparatus.NOTE 5The schematic diagram for a thin-heater apparatus (notshown) is similar, except the hot plate is much thinner and is notpartitioned by a gap.5.2 Follow the procedure of eit
34、her Test Method C 177 orC 1114 with the following modifications.5.3 Select a semi-rigid material for the auxiliary insulationhaving a low thermal conductance so that heat gains or lossesfrom the face of the meter plate in contact with the auxiliaryinsulation will be small. The thickness and lateral
35、conductanceof the auxiliary insulation should be small enough to avoidsignificant effects on the heat transfer through the meter sectionof the auxiliary insulation due to heat transfer at the edge of theauxiliary insulation.NOTE 6The influence of edge effects for a particular apparatus andtest confi
36、guration can be determined experimentally as described in TestMethod C 177 or by computation using one of the procedures referencedin Test Method C 177 or described by Peavy and Rennex (2).5.4 Determine C8 of the auxiliary insulation over the tem-perature range of interest using one of the following
37、 proce-dures. Either Test Method C 177 or C 1114 in a separate testsetup for a matched pair of similar specimens, or in-situ asdescribed in Annex A1 will be used.C10440725.4.1 In the first instance using either Test Method C 177 orC 1114, a match pair of similar specimens is required so thateither s
38、ingle specimen subsequently can be used as theauxiliary insulation specimen.5.4.2 In the second instance using in-situ as described inAnnex A1, pairs of test are required, one with a smalltemperature difference across the test specimen and one with asmall temperature difference across the auxiliary
39、insulation.NOTE 7In 5.4 it is not intended for the user to determine values for C8for every test that is to be conducted. Rather determine C8 as a function oftemperature over the temperature range of interest so that a correspondingregression curve may be developed and used for subsequent testing.5.
40、5 When using a compressible material as the auxiliaryinsulation, determine C8 either at the same thickness as thatused in the single-sided mode of operation or compressed to (atleast) two slightly different thicknesses, thus allowing interpo-lation for the thickness actually used in the single-sided
41、 modeof operation.5.6 For an apparatus without a separate provision fordetermining the individual thicknesses of the two specimens onopposite sides of the hot plate, place three or more low-conductance rigid spacers near the outer periphery of the guardplate between the hot plate and the surface of
42、the auxiliary coldplate (see Test Method C 177). Compute the effective thicknessof the test specimen by subtracting the thickness of the rigidspacers (corrected for thermal expansion, if necessary) fromthe thickness that is determined for the test specimen plus theauxiliary insulation. In this case,
43、 the separate tests of thermalconductance according to 5.4 compression also should beconducted with rigid spacers.5.7 Maintain the cold plate at the desired temperature Tc.Provide power input to the hot plate to attain the desiredtemperature Thon the hot side of the test specimen.5.8 Maintain the te
44、mperature T8cas closely as practical tothe temperature T8h.5.9 Establish thermal steady-state conditions in accordancewith either Test Method C 177 or C 1114.5.10 Acquire the required test data and determine A, Qm,Th,T8h, and T8cin accordance with either Test Method C 177 orC 1114.6. Calculation6.1
45、Calculate the heat flow through the auxiliary insulationas follows:Q8 5 C8 A T8h2 T8c! (1)where:C8 is the thermal conductance of the auxiliary insulation at atemperature corresponding to (T8h+T8c)/2, as obtained accord-ing to 5.4.6.2 Calculate the heat flow through the specimen as follows:Q 5 Qm2 Q8
46、 (2)6.3 Use the value of Q, thus obtained to calculate steady-state thermal transmission properties, in accordance with eitherTest Method C 177 or C 1114. When appropriate, consultPractice C 1045 to calculate steady-state thermal transmissionproperties. For reference, calculation equations are provi
47、ded inAppendix X1.7. Sources of Experimental Error7.1 Errors in the determination of Q, can be introduced fromseveral sources, including measurement of the power input Qmto the meter plate; estimation of the heat flow, Q8, through theauxiliary insulation and, for guarded hot plates, estimation ofthe
48、 heat flow across the gap between the meter and guardplates, that is, gap error.7.2 Refer to either Test Method C 177 or C 1114 fordiscussion on the uncertainty in the measurement of themetered-area power (Qm).7.3 Estimate the uncertainty (DQ8)inQ8 by a propagation oferror using the terms in Eq 1. R
49、efer to Ku (3) for using errorpropagation formulas.NOTE 8The terms, Qmand Q8 in Eq 2 should be different by at leasttwo orders of magnitude, if possible. Thus, a large uncertainty in Q8 mayFIG. 1 Diagram Illustrating Single-Sided Mode of Operation of the Guarded-Hot-Plate ApparatusC1044073result in a small uncertainty in Q. For example, suppose that the ratioQm/Q8 is 100 and suppose that the ratio DQ/Q is 0.1. The percentageuncertainty in Q due to DQ, then, would be 0.1 %.7.4 Refer to Appendix X2 for a discussion of the gap error.8. Report8.1 Report
