1、Designation: D 5972 05Designation: 435/98An American National StandardStandard Test Method forFreezing Point of Aviation Fuels (Automatic PhaseTransition Method)1This standard is issued under the fixed designation D 5972; the number immediately following the designation indicates the year oforiginal
2、 adoption or, in the case of revision, 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. Scope*1.1 This test method covers the determination of the tem-perature bel
3、ow which solid hydrocarbon crystals form inaviation turbine fuels.1.2 This test method is designed to cover the temperaturerange of 80 to 20C; however, 2003 Joint ASTM / IPInterlaboratory Cooperative Test Program mentioned in 12.4has only demonstrated the test method with fuels havingfreezing points
4、 in the range of 42 to 60C.1.3 The values stated in SI units are to be regarded as thestandard.1.4 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 pr
5、actices 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:2D 2386 Test Method for Freezing Point of Aviation Fuels3. Terminology3.1 Definitions:3.1.1 freezing point, nin aviation fu
6、els, 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 Definitions of Terms Specific to This Standard:3.2.1 automatic phase transition method, nin this testmethod, the proce
7、dures 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 hydrocarbon crystals completely redis-solve into the liquid phase.3.2.2 Peltier device, na solid-state thermoelect
8、ric 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 currentapplied to the device.4. Summary of Test Method4.1 A specimen is cooled at a rate of 15 6 5C/min by aPelti
9、er device while continuously being illuminated by a lightsource. The specimen is continuously monitored by an array ofoptical detectors for the first formation of solid hydrocarboncrystals. Once the hydrocarbon crystals are formed, the speci-men is then warmed at a rate of 10 + 0.5C/min until the la
10、sthydrocarbon crystals return to the liquid phase. The detectorsare sufficient in number to ensure that any solid hydrocarboncrystals are detected. The specimen temperature at which thelast hydrocarbon crystals return to the liquid phase is recordedas the freezing point.5. Significance and Use5.1 Th
11、e 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 fuel system of the aircraft. The temperature of the fuel inthe aircraft tank normally decreases during flight depending
12、 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 require precise measure-ment of the freezing point.5.3 This test method produces results which have beenfound to be equi
13、valent to Test Method D 2386 and expressesresults to the nearest 0.1C, with improved precision over Test1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition appr
14、oved Nov. 1, 2005. Published November 2005. Originallyapproved in 1996. Last previous edition approved in 2002 as D 597202e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information,
15、refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Method D 2386. This test method also eliminates most of
16、 theoperator time and judgment required by Test Method D 2386.5.4 When specification requiresTest Method D 2386,donotsubstitute this test method or any other test method.6. Apparatus6.1 Automatic Apparatus3This apparatus consists of amicroprocessor-controlled test chamber that is capable ofcooling a
17、nd heating the test specimen, optically observing theappearance and disappearance of solid hydrocarbon crystals,and recording the temperature of 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
18、, light source, digital display, Peltierdevice, and a specimen temperature measuring device.6.3 The temperature measuring device in the specimen cupshall be capable of measuring the temperature of the testspecimen from 80 to +20C at a resolution of 0.1C andaccuracy of 0.1C.6.4 The apparatus shall be
19、 equipped with fittings to permitthe circulation of a liquid medium to remove heat generated bythe Peltier device and other electronic components 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
20、 cup of any atmospheric moisture.7. Reagents and Materials7.1 n-OctaneReagent grade is suitable. (WarningFlammable. Harmful if inhaled. Keep away from heat, sparks,and open flame.)7.2 Cooling MediumLiquid heat exchange medium toremove the heat generated by the Peltier device and otherelectronic comp
21、onents from the apparatus.NOTE 1Some apparatus are designed to use tap water as a coolingmedium to bring the specimen temperature to 60C. To achieve coolingof the specimen to 80C, provide circulation of the cooling medium at30C or lower to the apparatus. Since water freezes at 0C, a commercialor tec
22、hnical grade isopropanol is suitable as the cooling medium. Refer tothe manufacturers operating instructions on the relationship between thecooling medium temperature and the minimum specimen temperature.7.3 Purge GasA gas such as air, nitrogen, helium, orargon with a dew point below the lowest temp
23、erature attainedby the specimen under the conditions of the test. (WarningCompressed gas under high pressure.) (WarningInert gascan be an asphyxiant when inhaled.)7.4 Pipette, capable of dispensing 0.15 6 0.01 mL ofsample.7.5 Cotton SwabsPlastic- or paper-shaft cotton swabs toclean the specimen cup.
24、 (WarningThe use of swabs withwooden shafts may damage the mirrored surface of thespecimen cup.)8. Preparation of Apparatus8.1 Install the analyzer for operation in accordance with themanufacturers instructions.8.2 Turn on the liquid cooling medium and ensure itstemperature is appropriate for the sp
25、ecimen being tested inaccordance with the manufacturers instructions (see Note 1).8.3 Turn on the purge gas and ensure that it is regulated tothe appropriate pressure in accordance with the manufacturersinstructions.8.4 Turn on the main power switch of the analyzer.NOTE 2Some apparatus are capable o
26、f generating a source of drypurge gas, thus eliminating the need for an external supply of acompressed gas.9. Calibration and Standardization9.1 Ensure that all of the manufacturers instructions forcalibrating, checking, and operating the apparatus are fol-lowed.9.2 To verify the performance of the
27、apparatus, an aviationturbine fuel sample for which extensive data has been obtainedby freeze point, Test Method D 2386, may be used. Samplessuch as those used in the ASTM interlaboratory cross-checkprogram would meet this criterion. Such verification materialscan also be prepared from intracompany
28、cross-checks. Alter-natively, high-purity n-octane or n-nonane with known freez-ing points can be used to verify the calibration of thetemperature-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 R
29、inse the specimen cup by pipetting 0.15 6 0.01 mLofspecimen into the cup. Clean the specimen out of the cup byusing a cotton swab. The cup should be cleaned to the pointwhere no visible droplets of specimen remain in the cup.10.3 Rinse the cup a second time by repeating 10.2.10.4 Carefully measure 0
30、.15 6 0.01 mL of specimen intothe specimen cup.10.5 Close and lock the test chamber lid.10.6 Start the operation of the apparatus according to themanufacturers instructions. From this point up to and includ-ing the termination of the measurement, the apparatus auto-matically controls all operations.
31、 Purge gas and liquid coolingmedium will begin to flow through the apparatus. The Peltierdevice cools the specimen at a rate of 15 6 5C/min. Theoptical detectors continuously monitor the specimen for theformation of hydrocarbon crystals. The temperature of thespecimen is continuously monitored by th
32、e apparatus anddisplayed on its front panel. Once hydrocarbon crystals aredetected, the specimen is then warmed at 10 6 0.5C/min untilall the crystals redissolve into the liquid phase. When thedisappearance of the last crystals is detected, the specimentemperature is recorded and the measurement is
33、terminated.3The 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. 135-11960 Hammersmith Way, Richmond, B.C. Canada, V7A5C9. All the model series previously mentioned have identical test chamb
34、ers andelectronics. The distinction between different model series is the low temperaturelimit. Refer to manufacturers product information on the low-temperature limit ofvarious models. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your
35、 comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.D597205210.7 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.
36、Report11.1 Report the temperature recorded in 10.7 as the freezingpoint, Test Method D 5972.12. Precision and Bias12.1 RepeatabilityThe difference between two test resultsobtained by the same operator with the same apparatus underconstant operating conditions on identical test material would,in the
37、long run, in the normal and correct operation of this testmethod, exceed 0.54C only in one case in twenty.12.1.1 ReproducibilityThe difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would, inthe long run
38、, in the normal and correct operation of this testmethod, exceed 0.80C only in one case in twenty.12.2 BiasBecause there 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 theint
39、erlaboratory program4were examined for biases relative toTest Method D 2386. There was no lab bias demonstrated inthe 2003 Joint ASTM / IP Interlaboratory Cooperative TestProgram.512.4 The precision statements were derived from a 2003Joint ASTM / IP interlaboratory cooperative test program.Participa
40、nts analyzed 13 samples comprised of various aviationfuels over the temperature range of 42 to 60C. The 2003study did not include Jet B or JP4 samples. Twelve laboratoriesparticipated with the automatic phase transition apparatus and15 participated with the manual Test Method D 2386 testmethod. The
41、precision statistics were compiled and calculatedbased on the 0.1C resolution offered by the automatic phasetransition method. Models 70, 70V and 70X participated in thisstudy. Information on the types of samples and their respectiveaverage freezing point is contained in the research report.5NOTE 3I
42、n the 1994 interlaboratory study, the 30, 50 and 70 seriesmodels were used, and among all the fuels, all the differences were withinthe reproducibility of Test Method D 2386 (2.5C) except for two. Thesetwo were the only samples of fuels of Grades JP4 and Jet B, and for thesethe average results were
43、2.5C and 2.8C warmer than those of TestMethod D 2386. Based on these two samples in the 1994 interlaboratorystudy, 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
44、 crystalsANNEX(Mandatory Information)A1. DETAILED DESCRIPTION OF APPARATUSA1.1 Test Chamber, comprised of optical 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 t
45、o allowcleaning of specimen cup and introduction of new specimen.Once closed and locked, the chamber becomes airtight. 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
46、shown inFig. A1.1. The test chamber wall is made of black-coloredmetal and plastic components to minimize light reflection.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 transfe
47、r ofheat to and away from the specimen, through the metal bottom,is controlled by the Peltier device.A1.1.2 Temperature Sensor, reading to 0.1C and minimumaccuracy to 0.1C, permanently embedded into the bottom ofthe specimen cup and positioned less than 0.1 mm below thetop surface of the cup bottom.
48、 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 range. The range varies depending onthe model series. During specimen cooling, heat is tra
49、nsferredfrom the top of the device to the bottom. Since the top is in4Supporting data (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 International Headquarters andmay be obtained by requesting Research Report RR: D02-1572.FIG. A1.1 Schematic of Test ChamberD5972053thermal contact w
