ASTM E2029-1999(2004) Standard Test Method for Volumetric and Mass Flow Rate Measurement in a Duct Using Tracer Gas Dilution《用示踪气体稀释法测量管道中体积和质量流量率的标准试验方法》.pdf

1、Designation: E 2029 99 (Reapproved 2004)Standard Test Method forVolumetric and Mass Flow Rate Measurement in a DuctUsing Tracer Gas Dilution1This standard is issued under the fixed designation E 2029; the number immediately following the designation indicates the year oforiginal adoption or, in the

2、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. Scope1.1 This test method describes the measurement of thevolumetric and mass flow rate of a gas

3、 stream within a duct,stack, pipe, mine tunnel, or flue using a tracer gas dilutiontechnique. For editorial convenience all references in the textwill be to a duct, but it should be understood that this couldrefer equally well to a stack, pipe, mine tunnel, or flue.This testmethod is limited to thos

4、e applications where the gas streamand the tracer gas can be treated as ideal gases at the conditionsof the measurement. In this test method, the gas stream will bereferred as air, though it could be any another gas that exhibitsideal gas law behavior.1.2 This test method is not restricted to any pa

5、rticular tracergas although experimental experience has shown that certaingases are used more readily than others as suitable tracer gases.It is preferable that the tracer gas not be a natural componentof the gas stream.1.3 Use of this test method requires a knowledge of theprinciples of gas analysi

6、s and instrumentation. Correct use ofthe formulas presented here requires consistent use of units.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

7、 practices and to determine theapplicability of regulatory limitations prior to use. For specificprecautionary statements, see Section 7.2. Referenced Documents2.1 ASTM Standards:2D 3154 Test Method for Average Velocity in a Duct (PitotTube Method)D 3464 Test Method forAverage Velocity in a Duct Usi

8、ng aThermal Anemometer2.2 ANSI/ASME Standard:3ANSI/ASME TC 19.11985 (1994) Measurement Uncer-tainty: Instrument Apparatus3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 ideal gas, na gas or gas mixture for which the ratioof the pressure divided by product of the density and te

9、mpera-ture is a constant.3.1.2 mass flow, nthe total mass of air passing thesampling point per unit time (kg/s, lb/min).3.1.3 tracer gas, na gas that can be mixed with air andmeasured in very low concentrations.3.1.4 tracer gas analyzer, na device that measures theconcentration of tracer gas in an a

10、ir sample.3.1.5 tracer gas mass concentration, nthe ratio of themass of tracer gas in air to the total mass of the air-tracermixture. For an ideal gas, the mass concentration is indepen-dent of temperature and pressure.3.1.6 tracer gas molar concentration, nthe ratio of thenumber of moles of tracer

11、gas in air to the total number ofmoles of the air-tracer mixture.3.1.7 tracer gas volume concentration, nthe ratio of thevolume of tracer gas in air to the total volume of the air-tracermixture. For an ideal gas, the volume concentration is inde-pendent of temperature and pressure and is equal to th

12、e molarconcentration.3.1.8 volumetric flow, nthe total volume of air passing thesampling point per unit time (m3/s, ft3/min).3.2 Symbols:C = mass concentration4of tracer gas (ppb-mass, ppm-mass, ppt-mass)CU= upstream mass concentration4of tracer gas (ppb-mass, ppm-mass, ppt-mass)CD= downstream mass

13、concentration4of tracer gas(ppb-mass, ppm-mass, ppt-mass)1This test method is under the jurisdiction of ASTM Committee E06 onPerformance of Buildings and is the direct responsibility of Subcommittee E06.41on Air Leakage and Ventilation Performance.Current edition approved Oct 1, 2004. Published Octo

14、ber 2004. Originallyapproved in 1999. Last previous edition approved in 1999 as E 2029 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Sum

15、mary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.CI= injection stream mass concentration4of tracer

16、 gas(ppb-mass, ppm-mass, ppt-mass)c = volume concentration4of tracer gas (ppb, ppm,ppt)cU= upstream volume concentration4of tracer gas (ppb,ppm, ppt)cD= downstream volume concentration4of tracer gas(ppb, ppm, ppt)cI= injection volume concentration4of tracer gas (ppb,ppm, ppt)F = mass flow rate5(kg/s

17、 g/min, lb/min)FI= injection mass flow rate5(kg/s, g/min, lb/min)FU= upstream mass flow rate5(kg/s, g/min, lb/min)FD= downstream mass flow rate5(kg/s, g/min, lb/min)f = volumetric flow rate5(m3/s, L/min, cfm)fstd= volumetric flow rate at standard conditions5(m3/s,L/min, cfm)fI= injection volumetric

18、 flow rate5(m3/s, L/min, cfm)fU= upstream volumetric flow rate5(m3/s, L/min, cfm)fD= downstream volumetric flow rate5(m3/s, L/min,cfm)fIstd= injection volumetric flow rate5at standard condi-tions (m3/s, L/min, cfm)fUstd= upstream volumetric flow rate5at standard condi-tions (m3/s, L/min, cfm)fDstd=

19、downstream volumetric flow rate5at standard con-ditions (m3/s, L/min, cfm)r = density6(kg/m3, g/L, lb/ft3)ra= density6of gas stream without any tracer (kg/m3,g/L, lb/ft3)rt= density6of the tracer gas (kg/m3, g/L, lb/ft3)rI= density6of the injection gas mixture (kg/m3, g/L,lb/ft3)rU= density6of the u

20、pstream gas mixture (kg/m3, g/L,lb/ft3)rD= density6of the downstream gas mixture (kg/m3,g/L, lb/ft3)rtU= density6of the tracer gas at upstream conditions(kg/m3, g/L, lb/ft3)rtD= density6of the tracer gas at downstream conditions(kg/m3, g/L, lb/ft3)4. Summary of Test Method4.1 This test method descri

21、bes the use of a tracer gasdilution technique to infer the volumetric flow rate through aduct. In practice, tracer gas is injected into a duct at a knownmass or volumetric flow rate. Downstream of the injectionpoint gas samples are taken and are analyzed for the resultingtracer concentration. The ra

22、tio of the injection flow rate and thedownstream concentration represents the dilution volume perunit time or volumetric flow rate in the duct.5. Significance and Use5.1 The method presented here is a field method that may beused to determine mass and volume flow rates in ducts whereflow conditions

23、may be irregular and nonuniform. The gasflowing in the duct is considered to be an ideal gas.The methodmay be especially useful in those locations where conventionalpitot tube or thermal anemometer velocity measurements aredifficult or inappropriate due either to very low average flowvelocity or the

24、 lack of a suitable run of duct upstream anddownstream of the measurement location.5.2 This test method can produce the volumetric flow rate atstandard conditions without the need to determine gas streamcomposition, temperature, and water vapor content.5.3 This test method is useful for determining

25、mass orvolumetric flow rates in HVAC ducts, fume hoods, vent stacks,and mine tunnels, as well as in performing model studies ofpollution control devices.5.4 This test method is based on first principles (conserva-tion of mass) and does not require engineering assumptions.5.5 This test method does no

26、t require the measurement ofthe area of the duct or stack.5.6 The test method does not require flow straightening.5.7 The test method is independent of flow conditions, suchas angle, swirl, turbulence, reversals, and hence, does notrequire flow straightening.5.8 The dry volumetric airflow can be det

27、ermined by dryingthe air samples without measuring the water vapor concentra-tion.6. Apparatus6.1 The apparatus includes a source of tracer gas, means fordistributing the tracer gas in the duct, means for obtaining airsamples from the duct, and a gas analyzer to measure tracer gasconcentrations in t

28、he air samples.6.2 Tracer GasSee Appendix X1 for information ontracer gases and equipment used to measure their concentra-tions. Appendix X1 also contains tracer gas target concentra-tions and safety information.6.3 Tracer Gas Injection SourceThis normally is a cylin-der of compressed tracer gas eit

29、her pure or diluted in a carriersuch as air or nitrogen. Tracer release from the cylinder iscontrolled by a critical orifice or nozzle, a metering valve, anelectronic mass flow meter or mass flow controller, or other gasflow rate measurement and control device. A rotameter is notrecommended for this

30、 measurement unless of special design,calibration, and a corresponding decrease in measurementaccuracy is acceptable.6.4 Tracer Gas DistributionA single tube or a tubingnetwork is inserted into the duct to dispense tracer gas. Thetube or tubes may have either a single or multiple release pointsfor t

31、racer gas. For large cross-section ducts a network thatdistributes tracer gas over a wide area will facilitate measure-ment.6.5 Tracer SamplingThis is performed using tubing in-serted into the duct downstream of the injection point.Asingletube is inserted into the duct.Air samples are removed from t

32、heduct by means of a sampling pump to distribute tracer laden airto the analyzer either directly or by means of syringe samples.6.6 Gas AnalyzerThis device must be suited for the tracergas used and the concentrations expected in the duct being4Equations in this test method assume that all mass or vo

33、lume concentrations arein the same units.5Equations in this test method assume that all mass or volume flow rates are inthe same units.6Equations in this test method assume that all densities are in the same units.E 2029 99 (2004)2measured. It should be calibrated properly and exhibit aaccuracy of b

34、etter than 63 % at concentrations employed inthe measurement.7. Hazards7.1 Safety is the responsibility of the user of this testmethod. Tracer gases have safe maximum concentration limitsdue to health and, in some cases, explosive potential. Table 1presents, as a guide, the maximum allowable concent

35、ration inair for some tracer gasses that can be used for airflowmeasurements. The tracer gas supplier must provide a MaterialSafety Data Sheet (MSDS) that will provide information abouthealth, fire, and explosion hazards.7.2 Health LimitationsUse current OSHA information onthe permissible exposure l

36、imit (PEL), or the ACGIH thresholdlimit value (TLV) if the particular tracer is not listed with aPEL, to determine the safe concentration for the gas chosen forthe test. Never exceed the maximum safe concentration. It isgood practice to use a concentration that is at most one tenth ofthe maximum saf

37、e concentration. Avoid using tracer gases forwhich no PEL or TLV exists.7.3 Compressed Gas EquipmentObserve the supplierssafety information and CGAinformation on the transportation,use, and storage of compressed gas cylinders, regulators, andrelated equipment.8. Procedure for Measuring Mass and Volu

38、metricFlowrate8.1 Inject tracer of known concentration, CI(cI), and at aknown rate, FI(fI), into a flowing duct using proceduresprovided in Section 9.8.1.1 If the tracer gas analyzer is field calibrated using asingle point method, the injection rate, or injection concentra-tion, or a combination the

39、reof, should be adjusted to produce aconcentration at the sample location that is the same as thecalibration concentration to within 620 %.8.1.2 If the tracer gas analyzer is field calibrated using twocalibration points, the injection rate, or injection concentration,or a combination thereof, should

40、 be adjusted to produce aconcentration at the sample location that lies between the twocalibration points.8.1.3 If the tracer gas analyzer is field calibrated using morethan two calibration points, the injection rate, or injectionconcentration, or a combination thereof, should be adjusted toTABLE 1

41、Tracer Gases and Safety IssuesTracer Gas TLVAToxicity Chemical Reactivity CommentsHydrogen Asphyxiant Nontoxic Highly reactive in Fire and explosion hazardpresence of heat, when exposer to heat,flame, of O2flame, or O2Helium Asphyxiant Nontoxic InertCarbon Monoxide 25 ppm Combines with Highly reacti

42、ve Fire and explosion hazardhemoglobin to with O2when exposed to heat orcause anoxia flameCarbon Dioxide 5000 ppm Can be an eye Reacts vigorouslyirritant with some metals;soluble in waterSulfur Hexafluoride 1000 ppm Nontoxic Inert Thermal decompositionyields highly toxiccompoundsNitrous Oxide 25 ppm

43、 Moderately toxic Violent reaction Can form explosivewith aluminum; mixture with air; igniteswater soluble at high temperatureEthane Asphyxiant Nontoxic Flammable Incompatible withchlorine and oxidizingmaterialsMethane Asphyxiant Nontoxic Flammable Incompatible withchlorine and oxidizingmaterialsOct

44、ofluorocyclobutane 1000 ppm Low toxicity Nonflammable Thermal decomposition(Halocarbon C-318 yields highly toxiccompoundsBromotrifluoromethane 500 ppm Moderately toxid Incompatible with Dangerous in a fire(Halocarbon 13B1) by inhalation aluminumDichlorodifluoromethane 1000 ppm Central nervous Nonfla

45、mmable; Thermal decomposition(Halocarbon 12) system and eye can react violently yields highly toxicirritant; can be with aluminum compoundsnarcotic at highlevelsDichlorotetrafluoromethane 1000 ppm Can be asphyxiant, Can react violently Thermal decomposition(Halocarbon 116) mildly irritating, with al

46、uminum yields highly toxicnarcotic at high compoundslevelsAThreshold Limit Values for Chemical Substances in the Work Environment, American Conference of Governmental Industrial Hygienists (ACGIH), 1997.TABLE 2 Minimum Number of Down Stream Sample LocationsDuct Cross Sectional Area m2(ft2) Number of

47、 Areas Number of SamplesLess then 0.2 (2) 4 50.2 to 2.3 (2 to 25) 12 13Greater than 2.3 (25) 20 21E 2029 99 (2004)3produce a concentration at the sample location that lies at theapproximate midpoint of the calibration range.8.2 Obtain at least N measurements of the resulting concen-trations, CiD, at

48、 least ten diameters, or equivalent hydraulicdiameters for nonround cross section ducts, downstream of theinjection at the center of N-1 equal areas of the duct crosssection and one at the center of the duct. The number N isdetermined by Table 2 depending on the duct size.8.3 If recirculation is pos

49、sible or likely, N samples CiUin thecenter of duct upstream of the injection point should be takenwithin 10 s of the time a downstream sample is taken. Ifrecirculation does not exist, take at least one upstream samplebefore and after taking the downstream samples.8.4 At each time a downstream sample is taken, the injec-tion flow rate FiIshall be recorded.8.5 Calculate the following quantities in either mass, vol-ume, or dry concentration depending on results desired:8.5.1 The average downstream concentration CD:CD51ND(i51NDCDi(1)where NDis the number of downstream