ASTM D3154-2000(2006) Standard Test Method for Average Velocity in a Duct (Pitot Tube Method)《导管中平均速度的标准试验方法(皮托管法)》.pdf

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1、Designation: D 3154 00 (Reapproved 2006)Standard Test Method forAverage Velocity in a Duct (Pitot Tube Method)1This standard is issued under the fixed designation D 3154; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of

2、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 measurement of the averagevelocity of a gas stream for the purpose of determining gasflow

3、in a stack, duct, or flue. Although technically complex, itis generally considered the most accurate and often the onlypractical test method for taking velocity measurements.1.2 This test method is suitable for measuring gas velocitiesabove 3 m/s (10 ft/s).1.3 This test method provides procedures fo

4、r determiningstack gas composition and moisture content.1.4 The values stated in SI units are to be regarded asstandard. The inch-pound units given in parentheses are forinformation only.1.5 This test method is applicable to conditions wheresteady-state flow occurs, and for constant fluid conditions

5、. Ifthese conditions are not meant, other methods must be used.1.6 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 practices and determine the applic

6、a-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1071 Test Methods for Volumetric Measurement of Gas-eous Fuel SamplesD 1193 Specification for Reagent WaterD 1356 Terminology Relating to Sampling and Analysis ofAtmospheresD 3195 Practice for Rotameter Cali

7、brationD 3631 Test Methods for Measuring Surface AtmosphericPressureD 3685/D 3685M Test Methods for Sampling and Determi-nation of Particulate Matter in Stack GasesD 3796 Practice for Calibration of Type S Pitot TubesE1 Specification for ASTM Liquid-in-Glass ThermometersE 337 Test Method for Measuri

8、ng Humidity with a Psy-chrometer (the Measurement of Wet- and Dry-Bulb Tem-peratures)2.2 EPA Standards:EPA-600/9-76-005 Quality Assurance Handbook for AirPollution Measurement Systems. Vol I. Principles3EPA-600/4-77-027b Quality Assurance Handbook for AirPollution Measurement Systems. Vol. III. Stat

9、ionarySource Specific Methods32.3 ASME Standards:ASME Performance Test Code: PTC 19.10-1968, Flue andExhaust Gas Analysis4ASME Performance Test Code: PTC 19.10-1981 Part 10,Flue and Exhaust Measurements: Instruments and Appa-ratus4ASME Performance Test Code: PTC 38-1980, Determiningthe Concentration

10、 of Particulate Matter in a Gas Stream42.4 Code of Federal Regulation:CFR Part 50 Standards of Performance for StationarySources, Appendix A; Test Methods 1 through 433. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method, referto Terminology D 1356.3.2 Descriptions of

11、 Symbols Specific to This Standard:A = cross-sectional area of stack, m2(ft2).Bws= water vapor in the gas stream, proportion byvolume.Cp= pitot tube coefficient, dimensionless.Ds= internal diameter of stack, cm, (in.).1This test method is under the jurisdiction of ASTM Committee D22 on AirQuality an

12、d is the direct responsibility of Subcommittee D22.03 on AmbientAtmospheres and Source Emissions.Current edition approved April 1, 2006. Published May 2006. Originallyapproved in 1972. Last previous edition approved in 2000 as D 3154 - 00.2For referenced ASTM standards, visit the ASTM website, www.a

13、stm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washin

14、gton, DC 20401.4Available from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Kp= pitot tube constant:=128.9 m

15、/sFg/g 2 mol!K!G1/2, (SI),=85.29 ft/sFlb/lb 2 mol!R!G1/2, (inch-pound).m = mean velocity, m/s (ft/s).Md= molecular weight of stack gas, dry basis,g/g mol (lb/lb mol).Ms= molecular weight of stack gas, wet basis,g/g mol (lb/lb mol).Mw= molecular weight of water, 18.0 g/g mol(18.0 lb/lb mol).N = numbe

16、r of sampling points across a diam-eter.n = nth sampling point from center of stack.Dp = velocity head of stack gas, kPa (in. water).Pstatic= static pressure of stack gas, kPa (in. water).Pbar= barometric pressure, kPa (in. Hg).Pm= absolute pressure at the dry gas meter (forthis test method it equal

17、s Pbar), kPa (in.Hg).Ps= absolute stack gas pressure, kPa (mm Hg).Pstd= standard ambient atmospheric pressure,101.3 kPa (760 mm Hg).%CO2= percent CO2in the stack gas, by volume,dry basis.%(N2+ CO) = sum of the percents of N2and CO in thestack gas, by volume, dry basis.%O2= percent O2in the stack gas

18、, by volume, drybasis.Qstd= dry volumetric stack gas flow rate correctedto standard conditions, dsm3/h (dsft3/h).R = ideal gas constant, 0.08312 (kPa) (m2)/g mol) (K) (SI system) or 21.85 (in. Hg)(ft2)/(lb mole) (R) (inch-pound).rn= radial distance from center of stack to nthsampling point, cm (in.)

19、.rw= density of water, 0.9971 g/mL (0.002194lb/mL) at 25C (77F).ST= between laboratory bias, m/s (ft/s).Ss= among single laboratory bias, m/s (ft/s).Tm= absolute average dry gas meter temperature,K (R).Ts= stack gas temperature, K ( R).Tstd= standard absolute temperature, 298 K (537R).Vi= initial vo

20、lume of condenser water, mL.Vf= final volume of condenser water, mL.Vm= volume of gas sample measured by the drygas meter, dm3(dft3).vs= stack gas velocity, m/s (ft/s).Vm(std)= volume of gas sample measured by the drygas meter, corrected to standard conditions,dm3(dft3).Vwc(std)= volume of water vap

21、or condensed, cor-rected to standard conditions, sm3(sft3).Vwsg(std)= volume of water vapor collected in silicagel, corrected to standard conditions,sm3(sft3).Wf= final mass of silica gel or silica gel plusimpinger, g.Wi= initial mass of silica gel or silica gel plusimpinger, g.Y = dry gas meter cal

22、ibration factor.0.28 = molecular weight of nitrogen or carbonmonoxide, divided by 100.0.32 = molecular weight of oxygen, divided by100.0.44 = molecular weight of carbon dioxide, di-vided by 100.3600 = conversion factor, s/h.4. Summary of Test Method4.1 This test method describes the use of instrumen

23、tation,equipment, and operational procedures necessary for the mea-surement and calculation of the average velocity of air or gasflows in flues, ducts, or stacks utilizing the pitot tube principle,with a manometer or draft gauge for pressure measurement.The stack gas composition and moisture content

24、 are deter-mined, using an Orsat analyzer for composition, and conden-sation techniques for moisture.5. Significance and Use5.1 The procedures presented in this test method are avail-able, in part, in Test Method D 3685/D 3685M, as well as theASME Methods given in 2.3 and Footnote 8,5the CFR givenin

25、 2.4, and the publication given in Footnote 9.66. Apparatus6.1 Pitot Tube, used in conjunction with a suitable manom-eter, provides the method for determining the velocity in aduct. The construction of a standard pitot tube and the methodof connecting it to a draft gauge are shown in Fig. 1. Details

26、 areshown in Fig. 2.6.1.1 To minimize the stem effect when the physical dimen-sions of the pitot tube are too large with respect to the flowscale, the diameter of the pitot tube barrel shall not exceed130the size of the duct diameter.6.1.2 At locations where the standard pitot tube cannot beused in

27、accordance with the sampling plan (see 8.1), or wheredust or moisture or both are present that may clog the smallholes in this instrument, a calibrated Staubscheibe pitot tube,commonly called a Type “S” pitot tube, shown in Fig. 3, shallbe used.6.1.3 The Type “S” pitot tube may be used in all applic

28、a-tions, provided that it has been calibrated. See Practice D 3796.5Colen, P., Corey, R. C., and Meyers, J. W., “Methods and Instrumentation forFurnace Heat Absorption Studies; Temperature and Composition of Gases atFurnace Outlets” Transaction of theAmerican Society of Mechanical Engineers, 71,pp.

29、96578, 1949.6Bulletin WP-50, Western Precipitation Division, Joy Manufacturing Co.,“Methods for Determination of Velocity, Dust, and Mist Content of Gases.”D 3154 00 (2006)2However, use of the standard pitot tube, where feasible, willgive additional accuracy.6.2 Differential Pressure GaugeA liquid-f

30、illed inclinedmanometer or an equivalent device used to measure thevelocity head. See Fig. 1. It is equipped with a 250 mm (10 in.)water column inclined manometer that has 0.25 mm (0.01 in.)divisions on the 0-to-25 mm (1 in.) inclined scale, and 2.5 mm(0.1 in.) divisions on the 25 to 250-mm (1 to 10

31、-in.) verticalscale. This type manometer (or other gauge of equivalentsensitivity) is satisfactory for measurements of Dp values aslow as 12.5 Pa (0.05 in. H2O).6.3 U-Tube ManometerA water or mercury filled instru-ment capable of measuring stack pressures to within 0.33 kPa(2.5 mm Hg).6.4 Thermocoup

32、leA device for measuring temperatureutilizing the fact that a small voltage is generated whenevertwo junctions of two dissimilar metals in an electric circuit areat different temperature levels.6.4.1 PotentiometerAn instrument for measuring smallvoltages, or for comparing small voltages with a known

33、voltage, used in conjuncture with the thermocouple.6.4.2 ThermometerAn ASTM thermometer meeting therequirements of Specification E1, for measuring the gastemperatures of small ducts.6.5 Mercury BarometerAn instrument capable of measur-ing ambient atmospheric pressure to 0.5 kPa. See Test MethodsD 36

34、31.6.6 Gas Density Determination EquipmentSee Fig. 4.6.6.1 ProbeA stainless steel or borosilicate glass tube,equipped with an in-stack or out-of-stack filter to removeparticulate matter.6.6.2 CondenserA water-cooled condenser that will notremove O2,CO2, CO, and N2, to remove excess moisture if thega

35、s stream contains over 2 % moisture by volume. The mainconsideration is that the condenser volume be kept to theminimum size because it will be more difficult to purge thesample train before collecting a sample if the condenser is toolarge. A 63-mm (0.25-in.) stainless steel coil, or equivalent,conn

36、ected to a water collection chamber with a capacity ofabout 40 mL is sufficient.6.6.3 ValveA needle valve to adjust the sample gas flowrate.6.6.4 PumpA leak-free diaphragm pump, to transport thesample gas to the flexible bag. A small surge tank shall beinstalled between the pump and the rate meter t

37、o eliminate thepulsation effect of the pump on the rate meter. Leak-test thepump, surge tank and rate meter (see 6.6.5), as described in9.4.2.6.6.5 Rate MeterA rotameter or equivalent rate meter,capable of measuring flow rates to within 62 % of the selectedflow rate.6.6.6 Flexible BagAleak-free iner

38、t plastic bag, having thecapacity adequate for the selected flow rate and length of timeof the test.Acapacity of 90 L (3.2 ft3) is usually sufficient. Thebag shall be leak-tested before each test, as described in 9.4.3.6.6.7 Vacuum GaugeAmercury manometer, or equivalentof 101.3 kPa (760 mm Hg) capac

39、ity, to be used for the sampletrain leak test. Test the gauge as described in 9.4.5.6.6.8 Orsat Gas AnalyzerSee Fig. 5. The Orsat gasanalyzer is used to analyze the gas sample for CO2,O2, and COstack gas concentrations, by successively passing the gasthrough adsorbents that remove the specific gaseo

40、us compo-nents. The difference in gas volumes before and after theabsorptions represents the amount of constituent gas in thesample.6.6.8.1 The analyzer shown in Fig. 5 includes a glass buretto measure the gas volume of the sample, a water jacket tomaintain constant temperature, a manifold to contro

41、l the gasflow, three absorption pipets (to remove CO2,O2, and CO),rubber expansion bags, and a liquid-filled leveling bottle tomove the gas sample within the analyzer.6.6.8.2 For CO2values 4 %, a standard Orsat gas analyzerwith a buret with 0.2 mL divisions and spacings divisions ofabout 1 mm (0.14

42、in.) is satisfactory. For lower CO2values orfor O2values 15 %, a buret with 0.1 mL divisions withspacings of 1 mm shall be used.6.6.8.3 The analyzer shall be leak-tested before and aftereach test, as described in 9.4.1.1.6.7 Gas Moisture Measuring Equipment See Fig. 6.6.7.1 ProbeSee 6.6.1.6.7.1.1 Pr

43、obe HeaterA heating system to maintain theexit gas stack temperature at 120 6 14C (250 6 25F) duringsampling.6.7.1.2 The probe shall be checked for breaks and leaksbefore each test, and the heater shall be checked to verify thatit can maintain an exit air temperature of 100C (212F) whenair is passed

44、 through the system at about 20 L/min (0.75ft3/min).6.7.2 CondensersFour glass impingers connected in se-ries with leak-free ground-glass fittings or equivalent leak-freenoncontaminating fittings.6.7.2.1 The first, third and fourth impingers shall be aGreenburg-Smith type, modified by replacing the

45、inserts withunconstricted 13 mm (0.5 in.) inside diameter glass tubeextending to within 13 mm of the flask bottom. The secondimpinger shall be of the standard Greenburg-Smith type.6.7.2.2 The fourth impinger outlet connecting shall be suchthat it will allow insertion of a temperature gauge. See 6.7.

46、3.6.7.2.3 The standard Greenburg-Smith impinger shall betested before use by allowing water to drain from the innertube. If water does not drain from the filled inner tube within8 s, replace the impinger.6.7.3 Temperature GaugeA thermometer capable of mea-suring within 1C (2F), and located at the ou

47、tlet of the fourthimpinger. See 6.7.2.2 and Specification E1.FIG. 1 Pitot TubeD 3154 00 (2006)36.7.4 Cooling SystemAn ice bath condenser with crushedice to contain the impingers and to condense the moisture in thesample gas stream.6.7.5 Metering SystemA metering system, consisting of avacuum gauge,

48、leak-free vacuum pump, thermometers, a drygas meter, differential pressure gauge and related equipment.See Test Method D 3685/D 3685M for details of this system.6.7.5.1 The system shall be leak-tested before and after eachtest, at both positive and negative pressures, following thedirections in 9.5.

49、4.6.7.6 BarometerSee 6.5.6.7.7 Graduated Cylinder or Triple Beam Balance or Both,to measure the water condensed in the impingers. Accuracyshall be 6 1mLor6 1 g. Cylinder shall be Class A, 250 mL,with #2 mL subdivisions.6.7.8 Stack Gas Temperature SensorA thermocouple orequivalent, to measure stack gas temperature to within 61C(2F) when the stack gas is suspected of being saturated orcontaining water droplets.Metric Equivalentsin. mm in. mm18 3.212 12.7532 4.01516 23.814 6.4 212 63.5516 7.9 5 127FIG. 2 Standard Pito