ASTM E1260-2003 Standard Test Method for Determining Liquid Drop Size Characteristics in a Spray Using Optical Nonimaging Light-Scattering Instruments《用光学无图信号光散射仪确定喷射时液滴尺寸特性的标准试验方法.pdf

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1、Designation: E 1260 03Standard Test Method forDetermining Liquid Drop Size Characteristics in a SprayUsing Optical Nonimaging Light-Scattering Instruments1This standard is issued under the fixed designation E 1260; the number immediately following the designation indicates the year oforiginal adopti

2、on 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.INTRODUCTIONThis standard is one of several describing a different class of test meth

3、ods for determining liquiddrop size characteristics in a spray. These test methods can be broadly distinguished as “optical” or“non-optical.” In the optical category there are test methods that essentially make images (such asphotographs) of drops that can be measured either manually or automaticall

4、y, and test methods thatdo not make images but use optical phenomena exhibited by single drops or ensembles of drops whichcan be recorded and used to calculate either individual drop sizes or the distribution of drop sizes inan ensemble. This test method deals with the latter class, and hence, is de

5、scribed as “nonimaging.” Thevarious optical phenomena involved are commonly described as “light-scattering.” Using any of thesetest methods, the spray is observed for a period of time during which a large number of drops isexamined, and the data are treated so as to derive drop-size statistics for t

6、he sample investigated.1. Scope1.1 The purpose of this test method is to obtain data whichcharacterize the sizes of liquid particles or drops such as areproduced by a spray nozzle or similar device under specifiedconditions using a specified liquid. The drops will generally bein the size range from

7、5-m to the order of 1 000-m diameter;they will occur in sprays which may be as small as a few cubiccentimetres or as large as several cubic metres. Typically thenumber density of the particles can vary significantly from onepoint to another.1.2 This test method is intended primarily for use instanda

8、rdizing measurements of the performance of spraypro-ducing devices. It is limited to those techniques and instru-ments that operate by passing a beam of light through the sprayand analyzing the light scattered by the droplets to derive sizeinformation. Such techniques do not produce images of indi-v

9、idual drops, and therefore, are known as “optical (nonimag-ing) instruments.”1.3 The measurements made, when referred to the entirespray being sampled, may be flux sensitive or spatial, asdefined in Practice E 799, depending on the techniques usedwith a particular instrument.1.4 This standard does n

10、ot 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. Referenced Documents2.1 ASTM Standar

11、ds:E 177 Practice for Use of the Terms Precision and Bias inASTM Test Methods2E 456 Terminology Relating to Quality and Statistics2E 799 Practice for Determining Data Criteria and Process-ing for Liquid Drop Size Analysis2E 1088 Definition of Terms Relating to Atomizing Devices2E 1296 Terminology Re

12、lating to Liquid Particle Statistics2E 1620 Terminology Relating to Liquid Particles and At-omization22.2 NFPA Standards:NFPA 30 Flammable and Combustible Liquids Code3NFPA 33 Spray Application Using Flammable and Combus-tible Materials31This test method is under the jurisdiction of ASTM Committee E

13、29 on ParticleSize Measurement and is the direct responsibility of Subcommittee E29.04 onLiquid Particle Measurement.Current edition approved May 10, 2003. Published August 2003. Originallyapproved in 1988. Last previous edition approved in 1999 as E 1260 99.2Annual Book of ASTM Standards, Vol 14.02

14、.3Available from the National Fire Protection Association, Battery-March Park,Quincey, MA 02269.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3. Terminology3.1 For terminology pertaining to this test method, refer toTerminology E 4

15、56, Practice E 799, Definitions E 1088, andTerminology E 1296.3.2 Definitions of Terms Specific to This Standard:3.2.1 spraythe term “spray” in this test method includesall ensembles, arrays, or clouds composed of liquid particles ordrops whether produced artificially or naturally. Although it isusu

16、al to consider a spray as implying significant motion of thedrops relative to the atmosphere there are situations in whichthe relative velocity is or becomes sufficiently low to benegligible. In this case, a “spray” is indistinguishable from a“cloud” which implies a static ensemble of drops.4. Summa

17、ry of Test Method4.1 The spray is examined by a means whereby a beam oflight passes through local regions, which make a representativesample, and one of the forms of light-scattering phenomenathat occur is detected by the instrument. The data are recorded,usually by data-processing equipment, and ar

18、e transformedmathematically into statistics characterizing the size distribu-tion These operations may be performed manually or automati-cally and the instrument may provide a visual display or aprinted report.5. Significance and Use5.1 The purpose of this test method is to provide data onliquid dro

19、p-size characteristics for sprays, as indicated byoptical nonimaging light-scattering instruments. The resultsobtained generally will be statistical in nature. The number ofvariables concerned in the production of liquid spray, togetherwith the variety of optical, electronic, and sampling systemsuse

20、d in different instruments, may contribute to variations inthe test results. Care must be exercised, therefore, whenattempting to compare data from samples obtained by differentmeans.6. Interferences6.1 Spray NozzleMany spray nozzles are designed withinternal liquid passages of small dimensions and

21、it is importantto ensure that these passages do not become blocked withforeign matter. Some nozzles have built-in filters or screens butin all cases it is advisable to fit a filter in the liquid supply lineimmediately upstream of the nozzle inlet to remove any solidparticles that are considered like

22、ly to cause problems.6.1.1 The use of one liquid to simulate another fuel mayaffect the performance of certain types of nozzle due todifferences in density, viscosity, and surface tension. In addi-tion, however, occasionally a problem may occur due todifferences in wetting the surfaces, for example,

23、 a nozzle testedpreviously in fuel (or other hydrocarbon) may exhibit a poorquality spray when first tested with water and may require theuse of a degreasing agent to remove traces of hydrocarbonfrom the surfaces containing the liquid.6.1.2 It is very important to protect the edges of thedischarge o

24、rifice of a spray nozzle from accidental damageprior to testing. This protection is best accomplished by the useof a cover over the discharge orifice of the nozzle duringstorage and installation on the test stand.6.2 Care must be exercised to prevent the ingress of liquiddrops into the instrument. T

25、he surfaces of lenses, mirrors, andwindows should be inspected at frequent intervals for cleanli-ness or damage and the manufacturers recommendationsfollowed.7. Apparatus7.1 Light Source, (including lasers),7.1.1 Optical Means, for producing a suitable beam thatpasses through a region of the spray,7

26、.1.2 Detecting Means, for recording light-scattering phe-nomena resulting from the liquid drops and means for trans-forming the observations into statistical estimates of drop sizeand dispersion characteristics, as shown in Fig. 1.7.2 Spray Chamber, preferably without components thatcould affect the

27、 optical behavior of the incident/scattered light(or have known effect thereon). It is convenient to employ thiswhen the spray or spray-producing device to be tested is smallin size relative to the apparatus. Use of this chamber may bedesirable to protect the optical and electronic components ofthe

28、apparatus from damage by the liquid spray (see alsoSection 8). In this case the apparatus is preferably securelyinstalled in a suitable location. The chamber should not affectthe normal formation of the spray.7.2.1 In cases where there are known or suspected steepdrop concentration gradients or vari

29、ations in the spray, forexample, in hollow-cone spray patterns, means shall be pro-vided for accurately locating the spraying device relative to thelight beam source and sensor. Provision should also be madefor selectively examining a number of different locations orregions in the spray.7.3 Operatin

30、g instructions shall be supplied by the manu-facturer or contractor of the apparatus or instrument. Theinstructions shall contain:7.3.1 Description of the operational principles of the instru-ment, oriented towards a trained technical operator. Referenceto relevant published literature shall be incl

31、uded;7.3.2 Recommendations for installation and use of theapparatus;FIG. 1 Diagram of Test ArrangementE12600327.3.3 Range of ambient temperature, humidity, and linevoltage variation, and any known limitations on the operatingenvironment;7.3.4 Ranges of liquid particle size, velocity, and numberdensi

32、ty or some equivalent parameter for which the instrumentis designed;7.3.5 Maintenance procedures recommended and required;7.3.6 Calibration verification procedures; and7.3.7 Statement of accuracy, repeatability, and reproducibil-ity of the resultant drop-size data.8. Hazards8.1 Safety Precautions:8.

33、1.1 WarningA spray of flammable liquid dispersed inair presents the risk of explosion and fire. Refer to NFPA 30 orNFPA 33 for information about safe practices for storage andhandling of flammable liquids and for spray processes involv-ing sprays of flammable liquids.8.1.2 WarningExposure to drops o

34、f various liquids byinhalation, ingestion, and skin contact, may constitute healthhazards.8.1.3 WarningEmission of some sprayed liquids into theatmosphere may be harmful to the environment or may pose ahealth risk.8.1.4 WarningLaser-based instruments contain lasers orother strong light sources which

35、 may pose a hazard to personsin their vicinity.8.1.5 Always read and follow the label, Federal, State andlocal guidelines for the handling, application, and disposal ofchemicals, and manufacturer instructions for instrument use.8.2 Containment is normally required.8.3 Additional hazards may need to

36、mitigated or avoided.9. Sampling9.1 For purposes of this test method each discrete test isconsidered a sample. If the duration of the test observationperiod is sufficiently long the sample may be regarded astime-averaged data for a large number of liquid particles for theparticular location in the s

37、pray. In this case there may be noneed for repetitive (replicated) tests.9.2 If the test objective is to obtain measurements asrepresentative as possible of the entire spray, then the samplinglocations shall be chosen to accomplish this purpose. If largedrop concentration gradients are apparent or d

38、etected inpreliminary tests, a sufficient number of sampling locationsshall be selected to allow an averaging procedure to beemployed.9.3 Where previously observed data exist relative to thedevice under test or where operating circumstances dictate itshall be permissible to take observations at a si

39、ngle location inthe spray and to report the result as a “standardized represen-tative determination.”9.4 In most instances, measurements at a single location arenot sufficient, so the spray should usually be traversed laterally,longitudinally, or axially, depending upon individual require-ments. The

40、 number of points to be tested should ensure that astatistically representative sample of the spray is made.10. Preparation of Apparatus10.1 Use of this test method requires that the presence of theinstrument, or any portions thereof, in proximity to the sprayshall not interfere with the process of

41、producing the spray (byatomization of the liquid) or the air patterns in the region beingexamined. This technique is described as “nonintrusive.”10.2 The instruments are invariably designed and calibratedto provide equivalent spherical diameters for particles. Theinstruments may be fully automatic i

42、n the sense that theyproduce a printed report of the results of each test, or they mayrequire manual processing of the data observed. In any case theindividuals performing the test methods are required to usejudgment in aligning the light beam in relation to the spray inaccordance with established p

43、rocedures for each subject. Theseprocedures may include multiple positions in the spray, repli-cation of tests, and other averaging techniques.10.3 Liquid particles may change size, for example, due toevaporation. Furthermore, breakup of liquids from jets orsheets into particles changes as the parti

44、cles travel from theirsource. The test procedure must take these factors into accountby recognizing the need for sufficient distance from the originof the spray for atomization to be essentially complete. For thisreason an instrument that requires dilution of a sample of thespray (by adding air, for

45、 example) in order to reduce theeffective drop concentration may not be suitable for use withvolatile liquids.10.4 The physical size or shape of the spray nozzle presentsno special problem provided the spray is visible and accessibleto the light beam. The shape and size of the spray, however,must be

46、 considered in relation to the view volume of the opticalsystem employed.11. Calibration Verification11.1 Optical nonimaging instruments and systems in generalhave optical or electronic components, or both, which neces-sitate validation of the overall instrument. A periodic check orverification of t

47、he performance of the instrument using par-ticles or particle images shall be performed.11.2 Unlike the solid particle situation there is no way ofpreserving a sample of liquid drops in spray form, so at thistime there is no primary standard available.11.3 In the absence of primary reference sprays,

48、 the follow-ing secondary reference methods are available:11.3.1 A monodisperse droplet generator,11.3.2 Solid beads or particles, and11.3.3 Reticles or graticules.11.4 A preserved spray nozzle also may be used periodicallyas an approximate check on the operation of the system whenproviding a carefu

49、lly defined reference spray.12. Conditioning12.1 In many cases the spray-producing devices to be testedwill have been designed to operate with specific liquids. Thesemay be of any kind including flammable, toxic, or otherwisehazardous substances, or multiple phase systems such asemulsions or drops containing air bubbles. It is important todetermine whether or not such liquids are compatible with orsuitable for the particular optical instrument to be employed. IfE1260033not compatible, then different measurement systems or substi-tute liquids could be considered. It is desirabl