1、Designation: D 5972 051An 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 adoption or, in t
2、he case of revision, 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.1NOTEThe IP logo and affiliation were removed editorially in August 2008.1. 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 to 20C; however, 2003 Joint ASTM / IPInterlaboratory Cooperative Test Program mentioned in 12.4has only demonst
4、rated the test method with fuels havingfreezing points 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 s
5、tandard 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:2D 2386 Test Method for Freezing Point of Aviation Fuels3. Terminolog
6、y3.1 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 Definitions of Terms Specific to This Standard:3.2.1 automatic p
7、hase 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 hydrocarbon crystals completely redis-solve into the liquid
8、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 currentapplied to the device.4. Summary of Test Method4.1 A
9、 specimen is cooled at a rate of 15 6 5C/min by aPeltier 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
10、is then warmed at a rate of 10 + 0.5C/min until the lasthydrocarbon 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 recor
11、dedas 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 fuel system of the aircraft. The temperature of the fuel inthe ai
12、rcraft 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 require precise measure-ment of the freezing point.5.3 This test m
13、ethod produces results which have beenfound to be equivalent 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 Subc
14、ommitteeD02.07 on Flow Properties.Current edition approved Nov. 1, 2005. Published November 2005. Originallyapproved in 1996. Last previous edition approved in 2002 as D 5972021.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org.
15、For Annual Book of ASTMStandards volume information, 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.Me
16、thod D 2386. This test method also eliminates most of 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 amicroprocesso
17、r-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 of the specimen. A detaileddescription of the apparatus is provided in Annex A1.6.2 The apparatus shall b
18、e 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 specimen cupshall be capable of measuring the temperature of the testspecimen from 80 to +20C at a resolution o
19、f 0.1C andaccuracy of 0.1C.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 components of theapparatus.6.5 The apparatus shall be equipped with fittings to permitthe circulation of purge g
20、as 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. Keep away from heat, sparks,and open flame.)7.2 Cooling MediumLiquid heat exchange medium toremove the heat gen
21、erated 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 60C. To achieve coolingof the specimen to 80C, provide circulation of the cooling medium at30C or lower to the app
22、aratus. Since water freezes at 0C, a commercialor technical 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, h
23、elium, 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 an asphyxiant when inhaled.)7.4 Pipette, capable of dispensing 0.15 6 0.01 mL ofsample.7.5 Cotton SwabsPlastic-
24、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 Install the analyzer for operation in accordance with themanufacturers instructions.8.2 Turn on the liquid cooling mediu
25、m 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 regulated tothe appropriate pressure in accordance with the manufacturersinstructions.8.4 Turn on the main power swit
26、ch 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 Standardization9.1 Ensure that all of the manufacturers instructions forcalibrating, checking, and operating the apparatu
27、s 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 D 2386, may be used. Samplessuch as those used in the ASTM interlaboratory cross-checkprogram would meet this criterion. Such verifica
28、tion materialscan also be prepared from intracompany 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
29、 cupinside the test chamber with a cotton swab.10.2 Rinse 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 s
30、econd time by repeating 10.2.10.4 Carefully measure 0.15 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,
31、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 6 5C/min. Theoptical detectors continuously monitor the specimen for theformation of hydrocarbon crystals. The tempe
32、rature of thespecimen is continuously monitored by the 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 sp
33、ecimentemperature is recorded and the measurement is 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
34、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 models. If you are aware of alternative suppliers, please provide thi
35、sinformation to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.D5972051210.7 The freezing point value will be displayed by theapparatus.10.8 Unlock and open the test chamber lid and clean thesp
36、ecimen out of the specimen cup with a cotton swab.11. 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 operati
37、ng conditions on identical test material would,in the 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 laborat
38、ories on identical test material would, inthe long run, 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 Re
39、lative BiasThe results for all the samples from theinterlaboratory 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 /
40、 IP interlaboratory cooperative test program.Participants 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 participat
41、ed with the manual Test Method D 2386 testmethod. The 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 freez
42、ing point is contained in the research report.5NOTE 3In 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
43、 JP4 and Jet B, and for thesethe average results were 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 turbin
44、e fuels; freezing point; Peltier; thermo-electric; wax 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
45、 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 airtight. AnO-ring is used to seal the mating surfaces between the lid andthe rest of the chamber. The air trapped in the closed chamberi
46、s 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 reflection.A1.1.1 Specimen Cup, comprised of a black plastic wall anda highly polished metal bottom. The polished surface of thebottom
47、 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.A1.1.2 Temperature Sensor, reading to 0.1C and minimumaccuracy to 0.1C, permanently embedded into the bottom ofthe specimen cup and positioned le
48、ss 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 range. The range varies depending on
49、the model series. During specimen cooling, heat is transferredfrom 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.F
