1、The International Authority on Air System ComponentsAIR MOVEMENT AND CONTROLASSOCIATION INTERNATIONAL, INC.ANSI/AMCAStandard 250-12Laboratory Methods of TestingJet Tunnel Fans for PerformanceAn American National StandardApproved by ANSI on February 22, 2012ANSI/AMCA Standard 250-12Laboratory Methods
2、 of TestingJet Tunnel Fans for PerformanceAir Movement and Control Association International30 W. University DriveArlington Heights, Illinois60004ANSI/AMCA Standard 250-05 was adopted by the membership of the Air Movement and Control Association International, Inc. on 14 January 2001. It was approve
3、d by ANSI as an American National Standard on 31 August 2005. The 2012 revision of Standard 250 was approved by ANSI on February 22, 2012. 2012 by Air Movement and Control Association International, Inc.All rights reserved. Reproduction or translation of any part of this work beyond that permitted b
4、y Sections 107 and 108 of the United States Copyright Act without the permission of the copyright owner is unlawful. Requests for permission or further information should be addressed to the Executive Director, Air Movement and Control Association International, Inc. at 30 West University Drive, Arl
5、ington Heights, IL 60004-1893 U.S.A.Air Movement and Control Association International, Inc. will consider and decide all written complaints regarding its standards, certification programs, or interpretations thereof. For information on procedures for submitting and handling complaints, write to:Air
6、 Movement and Control Association International30 West University DriveArlington Heights, IL 60004-1893 U.S.A.AMCA International, Incorporatedc/o Federation of Environmental Trade Associations2 Waltham Court, Milley Lane, Hare HatchReading, Berkshire, United KingdomRG10 9THAMCA uses its best efforts
7、 to produce standards for the benefit of the industry and the public in light of avail-able information and accepted industry practices. However, AMCA does not guarantee, certify or assure the safety or performance of any products, components or systems tested, designed, installed or operat-ed in ac
8、cordance with AMCA standards or that any tests conducted under its standards will be non-hazard-ous or free from risk.AMCA PublicationsAuthorityCopyrightObjectionsDisclaimerAng Swee Hock Lawrence DongGuan Wolter Chemco Ventilation LtdRoberto Arias Zitron, S.A.John Cermak Acme Engineering and Manufac
9、turing CorporationSisir Chakraborty CB Doctor Ventilators Pvt. Ltd. David Ortiz Gomez Soler the sum of gauge pres-sure and atmospheric pressure. The value is always positive.3.1.4 Barometric pressureThe absolute pressure exerted by the atmosphere at a loca-tion of measurement.3.1.5 Dry-bulb temperat
10、ureAir temperature measured by a temperature-sensing device without modifications to compensate for the effect of humidity.3.1.6 Static pressure at a pointThat portion of air pressure that exists by virtue of the degree of compression only. If expressed as gauge pressure, it may be negative or posit
11、ive. 3.1.7 Volume airflow rate The volume of air that passes through a given area in unit time.2 | ANSI/AMCA 250-12Actual Cubic Meters per Second (actual m3/s), or Actual Cubic Feet per Minute (acfm): The actual volume airflow rate at any point in an air system, at the existing density at the plane
12、passing through the point of measurement.3.1.8 Average air velocityThe volume airflow at a plane divided by the cross-section-al area of that plane.3.1.9 Fan dynamic pressureThe effective dynamic pressure at the fan outlet calculated from the effective fan outlet velocity and the inlet density. It i
13、s representative of the dynamic component of the fan out-put. The effective dynamic pressure varies from the average dynamic pressure as the former excludes the energy flux due to departures from the uniform axial velocity distribution.3.1.10 Fan outlet areaThe gross inside area measured at the plan
14、e(s) of the out-let openings. 1) If the silencer centerbody reaches the outlet plane of the fan then the “fan outlet area” is defined as the annulus area at the fan outlet plane as shown in Figure 1A. 2) If the fan has a silencer without centerbody, Figure 1B, the outlet area will be close to the cr
15、oss-sectional area inside the silencer in order to clear any exit bellmouth form. 3) For a fan without a silencer, Figure 1C, the outlet area will approach the annulus area between the casing and the motor but with some increase, as defined in the diagram, for the distance between the motor and the
16、outlet.4) Where the motor is on the upstream side, Figure 1C is applied to the impeller hub rather than the motor - as illustrated.3.1.11 Effective fan outlet velocityCalculated air velocity based on fan thrust, inlet air density and fan outlet area.3.1.12 Fan outlet velocityAverage velocity of air
17、emerging from an outlet measured in the plane of the outlet.3.1.13 Air powerPower output which is the product of the inlet volume airflow and the fan dynamic pressure.3.1.14 Impeller powerThe mechanical power supplied to the fan impeller.3.1.15 Motor input powerThe electrical power supplied to the t
18、erminals of an electric motor drive.3.1.16 Rotational speedThe rotational speed of an impeller. If a fan has more than one impeller, fan speeds are the rotative speeds of each impeller.3.1.17 Mean blade speedThe tangential velocity at 1/2 (or 0.7071) times the blade height between impeller hub and t
19、ip. 3.1.18 ThrustThe force exerted by a fan in a specific direction.Figure 1Effective Fan Outlet AreaANSI/AMCA 250-12 | 33.1.19 Fan efficiencyRatio of the air power to the impeller power, expressed as a percentage.3.1.20 Overall efficiencyRatio of the air power to the motor input power, expressed as
20、 a percentage.3.1.21 Thrust/power ratioRatio of the thrust to impeller power.Note: An alternative definition of thrust efficiency is defined as thrust divided by the motor input power. This results in a lower figure as the motor losses are also included.3.1.22 FanA device that utilizes a power drive
21、n rotating impeller for moving air or gases. The internal energy (enthalpy) increase imparted by a fan to a gas does not exceed 25 kJ/kg (10.75 BTU/lbm).3.1.23 Jet tunnel fanA fan used for producing a jet of air in a space and uncon-nected to any ducting. Typical function is to add momentum to the a
22、ir within a duct or tunnel.3.1.24 Fan guardA screen or other device to prevent ingestion of objects at the inlet or outlet of a fan.Note: Guards can have a marked effect on the thrust per-formance and sound level. Where they are specified, it shall be made quite clear between the supplier and his cu
23、stomer whether the performance includes the effect of the guards.3.1.25 ChamberAn airway in which the air velocity is small compared to that at the fan inlet or outlet.3.1.26 Test enclosureA room, or other space used for the purposes of testing.3.1.27 Sound power level, LwAcoustic power rating from
24、a sound source measured in decibels and equal to 10 times the logarithm (base 10) of the acoustic power in watts with reference to 10 10-12watts.3.1.28 Sound pressure level, LpThe acoustic pressure at a point in space where the micro-phone or listeners ear is situated. It is defined as 20 times the
25、logarithm (base 10) of the sound pressure fluctuation with reference to 20 mPa.3.1.29 Frequency range of interestThe frequency range including the octave bands with cen-ter frequencies between 63 Hz and 8 kHz, and the one-third octave bands with center frequencies between 50 Hz and 10 kHz.3.1.30 Imp
26、eller balance gradeThe impeller balance specification in accordance with the method detailed in ANSI S2.19 and to the grade specified in ANSI/AMCA 204.3.1.31 Fan vibration velocityThe filtered vibration velocity in the frequency range 10 Hz through 10 kHz measured in accordance with this standard.3.
27、1.32 Shall and shouldIn AMCA standards, the word “shall” is understood to be nor-mative; the word “should” as advisory.3.2 SymbolsSee Table 1 for a list of symbols.4. Characteristics to be Measured4.1 GeneralIn order for a jet-type tunnel fan to be correctly applied and give satisfactory performance
28、 and reliability in service, it is necessary to determine a number of technical performance characteristics in addition to knowing the more obvious mechanical features such as weight and overall installation dimensions.4.2 Volume airflow rateVolume airflow rate need only be measured if required for
29、contractual reasons. The effective outlet velocity, not the vol-umetric airflow rate, is used to evaluate the optimum num-ber, size and spacing of jet fans in a tunnel. Higher veloci-ties reduce thrust efficiency but the effect of tunnel air veloc-ity on thrust is reduced.4.3 Thrust Friction on the
30、tunnel walls, inlet and outlet losses and, sometimes, traffic drag combined with gradients and wind effects at tunnel portals, result in a pressure drop through the tunnel. The pressure drop is matched by the sum of the pressure increases by the jet fans due to the momentum transfer between the fan
31、discharge airflow and the airflow in the tunnel. As it is impossible to measure the momentum of the fan discharge airflow, and the rate of change of momen-tum is equal and opposite to the thrust, thrust is measured instead.The process of providing additional momentum to the tunnel air helps to maint
32、ain air quality.Table 1Symbols and SubscriptsSymbol Description SI Unit IP UnitAeffArea of fan inlet or outlet m2ft2D Fan diameter mm in.d3Length of upstream chamber side m ftP Differential pressure across a flow measuring device Pa in. wgG Impeller balance grade ANSI/AMCA 204 dimensionlessLpbBackgr
33、ound sound pressure level dB dBLp(m)Recorded sound power level of fan and room back-ground as measured over the normal mic. pathdB dBLp(r)Recorded sound pressure level of RSS and roombackground as measured over the normal mic. pathdB dBLwSound power level, re 1 pW dB dBLw(r)Sound power level of the
34、RSS dB dBLw1Sound power level (forward) dB dBLw2Sound power level (reverse) dB dBLpSound pressure level dB dBN Impeller rotational speed rpm rpmPa Atmospheric pressure in test enclosure Pa in. HgpdFan dynamic pressure Pa in. wgPEMotor input power W hpPFFan air power W hpPRImpeller power W hpqmMass a
35、irflow kg/s lbm/sqvVolume airflow m3/s cfmrTThrust/power ratio N/kW lbf/HptaAtmospheric temperature in test enclosure (dry-bulb) C FTcCalculated thrust N lbfTmMeasured thrust N lbfumMean blade speed (see definition in Section 3.1.17) m/s ft/minvtMean through airflow velocity in atunnel at a specifie
36、d sectionm/s ft/minveffEffective fan outlet air velocity m/s ft/minV1Fan vibration velocity at upstreammeasuring position - rms valuemm/s in./sV2Fan vibration velocity at downstream measuring position - rms valuemm/s in./shrFan efficiency % %heOverall efficiency % %raInlet air density taken as equal
37、 to theair density in the test enclosurekg/m3lbm/ft3ANSI/AMCA 250-12 | 54.4 Input power In order to calculate the cost of operating the jet tunnel fans (there may be a substantial number) in a tunnel, it is neces-sary to know the input power to the fan motor.4.5 Sound power level Sound levels, usual
38、ly at inlet and outlet, are established in order to ensure that the jet fan and silencer combination is optimized to match the tunnel sound level requirements.4.6 Vibration velocityFor reasons of safety, reliability and maintainability, it is essential that a realistic vibration velocity is specifie
39、d and recorded on tunnel fans. These shall be measured at the support points in accordance with ANSI/AMCA 204. 5. Instrumentation and Measurements 5.1 Volume airflow rate5.1.1 Instruments for the measurement of pressureManometers for the measurement of differential pressure, and barometers for the m
40、easurement of atmospheric pres-sure in the test enclosure, shall comply with the require-ments of ANSI/AMCA 210 or ISO 5801.5.1.2 Instruments for the measurement of temperatureThermometer(s) shall comply with the requirements of ANSI/AMCA 210 (ISO 5801).5.2 Thrust5.2.1 Force balance systemsBy the us
41、e of calibrated weights, force balance systems shall permit the determination of force or thrust with an allowable uncertainty of no greater than 1%.5.2.2 Force transducersBy the use of calibrated weights, force transducers shall permit the determination of thrust with an allowable uncer-tainty no g
42、reater than 1%.5.2.3 Dimensions and areasThe measurement of dimensions and the determination of areas shall be in accordance with ANSI/AMCA 210 or ISO 5801.5.3 Input power Determination of the power input to the electric motor or to the impeller shall be carried out in accordance with ANSI/AMCA 210
43、or ISO 5801.5.4 Impeller rotational speedImpeller rotational speed shall be determined in accordance with ANSI/AMCA 210 or ISO 5801.5.5 Sound levelThe sound level measuring system including microphones, windshields, cables, amplifiers and frequency analyzer shall be in accordance with the requiremen
44、ts given in ANSI/AMCA 300.5.6 Vibration velocityInstruments to measure rms vibration velocity shall be used to record fan vibration velocities. These shall be in accor-dance with ANSI/AMCA 204.6. Determination of Airflow Rate6.1 GeneralThere are three methods available for the determination of airfl
45、ow rate. The most convenient uses a venturi nozzle or conical inlet, connected upstream of the jet tunnel fan, as the airflow measuring device. The second makes use of an upstream chamber test configuration. In this case a boost-er fan forms part of the test setup enabling the fans operat-ing point
46、to be simulated correctly. The third method uses a Pitot traverse at the jet fan inlet.It should be noted that the airflow through a jet fan has no direct relationship with the airflow through a tunnel.6.2 Direct connected airflow measuring deviceThe airflow measuring device shall be connected by su
47、it-able means to the fan inlet as illustrated on Figure 2. Details of the venturi nozzle shall comply with ANSI/AMCA 210, Figure 4. Details of the conical inlet shall comply with ISO 5801, Figure 21. For the purpose of airflow rate determina-tion in accordance with this standard, an anti-swirl devic
48、e is not required.Airflow rate for the venturi nozzle is calculated in accordance with ANSI/AMCA 210, Section 8. Airflow rate for a conical inlet is calculated in accordance with ISO 5801 clause 24.6.3 Upstream chamber methodInstallation of the fan in the chamber is illustrated in Figure 3. This arr
49、angement simulates a free inlet, free outlet instal-lation. Upstream sections of the test assembly shall be in accordance with ANSI/AMCA 210 or ISO 5801.6 | ANSI/AMCA 250-12A venturi nozzle, quadrant inlet nozzle, or conical inlet can be used to determine airflow rate in accordance with ISO 5801, clauses 22, 24, and 25. Multiple nozzles may be used in accordance with ANSI/AMCA 210, Figure 14 or 15.In order to establish the correct operating point, with no adverse pressure across the fan, a test system booster fan shall be controlled such that:Ps3= Ps2
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