1、Designation: D5972 15Designation: 435/12Standard Test Method forFreezing Point of Aviation Fuels (Automatic PhaseTransition Method)1This standard is issued under the fixed designation D5972; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, 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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This test m
3、ethod covers the determination of the tem-perature below which solid hydrocarbon crystals form inaviation turbine fuels.1.2 This test method is designed to cover the temperaturerange of 80 C to 20 C; however, 2003 Joint ASTM/IPInterlaboratory Cooperative Test Program mentioned in 12.4has only demons
4、trated the test method with fuels havingfreezing points in the range of 42 C to 60 C.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated
5、 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. For specificwarning statements, see 7.1, 7.3, and 7.5.2. Referenced Documents2.1 ASTM Standards:2D2386 Te
6、st Method for Freezing Point of Aviation Fuels3. Terminology3.1 Definitions:3.1.1 freezing point, nin aviation fuels, the fuel tempera-ture at which solid hydrocarbon crystals, formed on cooling,disappear when the temperature of the fuel is allowed to riseunder specified conditions of test.3.2 Defin
7、itions of Terms Specific to This Standard:3.2.1 automatic phase transition method, nin this testmethod, the procedures of automatically cooling a liquidaviation fuel specimen until solid hydrocarbon crystals appear,followed by controlled warming and recording of the tempera-ture at which the solid h
8、ydrocarbon crystals completely redis-solve into the liquid phase.3.2.2 Peltier device, na solid-state thermoelectric deviceconstructed with dissimilar semiconductor materials, config-ured in such a way that it will transfer heat to and away froma test specimen dependent on the direction of electric
9、currentapplied to the device.4. Summary of Test Method4.1 Aspecimen is cooled at a rate of 15 Cmin 6 5 Cminby a Peltier device while continuously being illuminated by alight source. The specimen is continuously monitored by anarray of optical detectors for the first formation of solidhydrocarbon cry
10、stals. Once the hydrocarbon crystals areformed, the specimen is then warmed at a rate of 10 Cmin +0.5 Cmin until the last hydrocarbon crystals return to theliquid phase. The detectors are sufficient in number to ensurethat any solid hydrocarbon crystals are detected. The specimentemperature at which
11、 the last hydrocarbon crystals return to theliquid phase is recorded as the freezing point.5. Significance and Use5.1 The freezing point of an aviation fuel is the lowesttemperature at which the fuel remains free of solid hydrocar-bon crystals. These crystals can restrict the flow of fuel throughthe
12、 fuel system of the aircraft. The temperature of the fuel inthe aircraft tank normally decreases during flight depending onaircraft speed, altitude, and flight duration. The freezing pointof the fuel must always be lower than the minimum operationalfuel temperature.5.2 Petroleum blending operations
13、require precise measure-ment of the freezing point.5.3 This test method produces results which have beenfound to be equivalent to Test Method D2386 and expresses1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct resp
14、onsibility ofSubcommittee D02.07 on Flow Properties.Current edition approved Dec. 1, 2015. Published January 2016. Originallyapproved in 1996. Last previous edition approved in 2010 as D5972 05 (2010).DOI: 10.1520/D5972-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orconta
15、ct ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Co
16、nshohocken, PA 19428-2959. United States1results to the nearest 0.1 C, with improved precision over TestMethod D2386. This test method also eliminates most of theoperator time and judgment required by Test Method D2386.5.4 When specification requires Test Method D2386,donotsubstitute this test metho
17、d or any other test method.6. Apparatus6.1 Automatic Apparatus3This apparatus consists of amicroprocessor-controlled test chamber that is capable ofcooling and heating the test specimen, optically observing theappearance and disappearance of solid hydrocarbon crystals,and recording the temperature o
18、f the specimen. A detaileddescription of the apparatus is provided in Annex A1.6.2 The apparatus shall be equipped with a specimen cup,optical detector array, light source, digital display, Peltierdevice, and a specimen temperature measuring device.6.3 The temperature measuring device in the specime
19、n cupshall be capable of measuring the temperature of the testspecimen from 80 C to +20 C at a resolution of 0.1 C andaccuracy of 0.1 C.6.4 The apparatus shall be equipped with fittings to permitthe circulation of a liquid medium to remove heat generated bythe Peltier device and other electronic com
20、ponents of theapparatus.6.5 The apparatus shall be equipped with fittings to permitthe circulation of purge gas to purge the test chamber contain-ing the specimen cup of any atmospheric moisture.7. Reagents and Materials7.1 n-OctaneReagent grade is suitable. (WarningFlammable. Harmful if inhaled. Ke
21、ep away from heat, sparks,and open flame.)7.2 Cooling MediumLiquid heat exchange medium toremove the heat generated by the Peltier device and otherelectronic components from the apparatus.NOTE 1Some apparatus are designed to use tap water as a coolingmedium to bring the specimen temperature to 60 C.
22、 To achieve coolingof the specimen to 80 C, provide circulation of the cooling medium at30 C or lower to the apparatus. Since water freezes at 0 C, acommercial or technical grade isopropanol is suitable as the coolingmedium. Refer to the manufacturers operating instructions on therelationship betwee
23、n the cooling medium temperature and the minimumspecimen temperature.7.3 Purge GasA gas such as air, nitrogen, helium, orargon with a dew point below the lowest temperature attainedby the specimen under the conditions of the test. (WarningCompressed gas under high pressure.) (WarningInert gascan be
24、an asphyxiant when inhaled.)7.4 Pipette, capable of dispensing 0.15 mL 6 0.01 mL ofsample.7.5 Cotton SwabsPlastic- or paper-shaft cotton swabs toclean the specimen cup. (WarningThe use of swabs withwooden shafts may damage the mirrored surface of thespecimen cup.)8. Preparation of Apparatus8.1 Insta
25、ll the analyzer for operation in accordance with themanufacturers instructions.8.2 Turn on the liquid cooling medium and ensure itstemperature is appropriate for the specimen being tested inaccordance with the manufacturers instructions (see Note 1).8.3 Turn on the purge gas and ensure that it is re
26、gulated tothe appropriate pressure in accordance with the manufacturersinstructions.8.4 Turn on the main power switch of the analyzer.NOTE 2Some apparatus are capable of generating a source of drypurge gas, thus eliminating the need for an external supply of acompressed gas.9. Calibration and Standa
27、rdization9.1 Ensure that all of the manufacturers instructions forcalibrating, checking, and operating the apparatus are fol-lowed.9.2 To verify the performance of the apparatus, an aviationturbine fuel sample for which extensive data has been obtainedby freeze point, Test Method D2386, may be used.
28、 Samplessuch as those used in the ASTM interlaboratory cross-checkprogram would meet this criterion. Such verification materialscan also be prepared from intracompany cross-checks.Alternatively, high-purity n-octane or n-nonane with knownfreezing points can be used to verify the calibration of thete
29、mperature-measuring device in the apparatus.10. Procedure10.1 Open the test chamber lid and clean the specimen cupinside the test chamber with a cotton swab.10.2 Rinse the specimen cup by pipetting 0.15 mL 60.01 mL of specimen into the cup. Clean the specimen out ofthe cup by using a cotton swab. Th
30、e cup should be cleaned tothe point where no visible droplets of specimen remain in thecup.10.3 Rinse the cup a second time by repeating 10.2.10.4 Carefully measure 0.15 mL 6 0.01 mL of specimeninto the specimen cup.10.5 Close and lock the test chamber lid.10.6 Start the operation of the apparatus a
31、ccording to themanufacturers instructions. From this point up to and includ-ing the termination of the measurement, the apparatus auto-matically controls all operations. Purge gas and liquid coolingmedium will begin to flow through the apparatus. The Peltierdevice cools the specimen at a rate of 15
32、Cmin 6 5 Cmin.The optical detectors continuously monitor the specimen forthe formation of hydrocarbon crystals. The temperature of the3The sole source of supply of the Phase Technology Freezing Point AnalyzerModel Series 70, 70V, and 70X known to the committee at this time is PhaseTechnology, No. 13
33、5-11960 Hammersmith Way, Richmond, B.C. Canada, V7A5C9. All the model series previously mentioned have identical test chambers andelectronics. The distinction between different model series is the low temperaturelimit. Refer to manufacturers product information on the low-temperature limit ofvarious
34、 models. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.D5972 152specimen is continuously monitored by the apparatus
35、 anddisplayed on its front panel. Once hydrocarbon crystals aredetected, the specimen is then warmed at 10 Cmin 60.5 Cmin until all the crystals redissolve into the liquidphase. When the disappearance of the last crystals is detected,the specimen temperature is recorded and the measurement istermina
36、ted.10.7 The freezing point value will be displayed by theapparatus.10.8 Unlock and open the test chamber lid and clean thespecimen out of the specimen cup with a cotton swab.11. Report11.1 Report the temperature recorded in 10.7 as the freezingpoint, Test Method D5972.12. Precision and Bias12.1 Rep
37、eatabilityThe difference between two test resultsobtained by the same operator with the same apparatus underconstant operating conditions on identical test material would,in the long run, in the normal and correct operation of this testmethod, exceed 0.50 C only in one case in twenty.12.1.1 Reproduc
38、ibilityThe difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would, inthe long run, in the normal and correct operation of this testmethod, exceed 0.80 C only in one case in twenty.12.2 BiasBecause there
39、 are no liquid hydrocarbon mix-tures of known freezing point, which simulate aviation fuels,bias cannot be established.12.3 Relative BiasThe results for all the samples from theinterlaboratory program4were examined for biases relative toTest Method D2386. There was no lab bias demonstrated in the200
40、3 Joint ASTM / IP Interlaboratory Cooperative Test Pro-gram.512.4 The precision statements were derived from a 2003Joint ASTM/IP interlaboratory cooperative test program. Par-ticipants analyzed 13 samples comprised of various aviationfuels over the temperature range of 42 C to 60 C. The2003 study di
41、d not include Jet B or JP4 samples. Twelvelaboratories participated with the automatic phase transitionapparatus and 15 participated with the manual Test MethodD2386 test method. The precision statistics were compiled andcalculated based on the 0.1 C resolution offered by theautomatic phase transiti
42、on method. Models 70, 70V, and 70Xparticipated in this study. Information on the types of samplesand their respective average freezing point is contained in theresearch report.5NOTE 3In the 1994 interlaboratory study, the 30, 50, and 70 seriesmodels were used, and among all the fuels, all the differ
43、ences were withinthe reproducibility of Test Method D2386 (2.5 C) except for two. Thesetwo were the only samples of fuels of Grades JP4 and Jet B, and for thesethe average results were 2.5 C and 2.8 C warmer than those of TestMethod D2386. Based on these two samples in the 1994 interlaboratorystudy,
44、 there may be a bias for these sample types relative to the manualmethod for Jet B and JP4 samples.413. Keywords13.1 aviation turbine fuels; freezing point; Peltier; thermo-electric; wax crystalsANNEX(Mandatory Information)A1. DETAILED DESCRIPTION OF APPARATUSA1.1 Test Chamber, comprised of optical
45、detectors, lens,light source, specimen cup, temperature sensor, Peltier device,and heat sink arranged in a configuration as shown in Fig.A1.1. The lid of the test chamber can be opened to allowcleaning of specimen cup and introduction of new specimen.Once closed and locked, the chamber becomes airti
46、ght. AnO-ring is used to seal the mating surfaces between the lid andthe rest of the chamber. The air trapped in the closed chamberis purged by dry gas. The dry gas inlet and outlet are shown inFig. A1.1. The test chamber wall is made of black-coloredmetal and plastic components to minimize light re
47、flection.A1.1.1 Specimen Cup, comprised of a black plastic wall anda highly polished metal bottom. The polished surface of thebottom serves as a reflective surface for light. The transfer ofheat to and away from the specimen, through the metal bottom,is controlled by the Peltier device.4Supporting d
48、ata (the results of the 1994 Interlaboratory Cooperative TestProgram) have been filed atASTM International Headquarters and may be obtainedby requesting Research Report RR:D02-1385.5Supporting data (the results of the 2003 Joint ASTM/IP InterlaboratoryCooperative Test Program) have been filed atASTM
49、 International Headquarters andmay be obtained by requesting Research Report RR:D02-1572.D5972 153A1.1.2 Temperature Sensor, reading to 0.1 C and minimumaccuracy to 0.1 C, permanently embedded into the bottom ofthe specimen cup and positioned less than 0.1 mm below thetop surface of the cup bottom. This temperature sensor, whichis made of a single strand of platinum, provides accuratemeasurement of the specimen temperature.A1.1.3 Peltier Device, capable of controlling the specimentemperature over a wide rang
