德国国家计量院标准装置.ppt

德国国家计量院标准装置.ppt

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天大泰和德国国家计量院德国国家计量院（FTB）（FTB）热水标准装置热水标准装置天大泰和概述概述Nationalprimarystandardforvolumeflow-ratesofwater.Flow-rate:

31000m3/h.Temperatures:

390oCThemaximumReynoldsnumber5.5x106.Twoindependentweighingprocedures,toobtainhighly-valuablemeasurementresultsExpandedcombineduncertaintyof0.04%.天大泰和概述概述Testfacilityextendsover2floors.Twomeasuringsectionsof25mlength.Constantleveltankis11minheight.CollectiontankV=40m3.StoragetankV=65m3.Waterflowcanbesuppliedinfourdifferentoperationmodes天大泰和四种工作模式四种工作模式Frequencycontrolledcirculationpumpsupto1000m3/h.Constantleveltankforflowratesupto80m3/h,forpulsation-freewaterflowataconstantstaticpressure.Pressure-based“single”modeforflowratesupto200m3/h.Waterofthestoragetankisexpelledpulsationfreebycompressedairatpressuresupto5.5bar.Pressure-based“continuous”modeforflowratesupto1000m3/hatpressuresbetween1.5barand5.5bar.Theexpelledwaterofthestoragetankisrefilledcontinuouslyusingfrequencycontrolledpumpsbetweenthecollectionandthestoragetank.天大泰和其它特性其它特性Watertemperatureenteringmeasuringsectionsvarieslessthan100mKduring2hours.Additionallythedensityandtheconductivityofthewaterismeasured.PipediametersDN80toDN400doublewallpipe;smoothedinnersurfaces;andaflangesmismatchoflessthan50m.Thisallowsthewaterflowtoformanundisturbed,fullydevelopedturbulentflowprofile.Velocitydistributioncanbemeasuredviawindow-chambersusingaLaser-Doppler-Velocimeter;measuringvolume100minmaximumdimension天大泰和静态称重法静态称重法Theweighingtank（V=20m3）mountedonfourweighingplatforms.Thebalancecanbecalibratedwithinlessthan60sec.byanautomatedloadingandunloadingprocedure.36massstandards（560kgeach）isusedtodeterminethecalibrationcurveofthebalanceForthestaticmeasurementthemassofthewaterintheweighingtankisdeterminedwithin50grams.Theinletoftheweighingtankconsistsofasteelplatewith250drainpipes,inordertoensurelowanddefinedmomentumtransferfromthewaterflowingintotheweighingtank.天大泰和双换向器结构双换向器结构Ontopoftheweighingtankaretwodivertersofdifferentsizes.ToavoidevaporationlossesduringthefillingtimeToallowthedeflectionoflargevolumeflowrateswithaminimumofmomentumtransferinshortesttimes.Theswitchingprocesstakesapproximately1second.Repeatabilityoftheswitchingprocessisbetterthan13ms.Beforethefillingprocess,providingtheweighingtankwithairofwelldefinedtemperatureandhumidity.Duringthefilling,humidityandtemperatureofexpelledairfromtheweighingtankiscontrolled.天大泰和动态称重法动态称重法Besidesstaticweighingprocedure,theweighingsystemcanbeusedinadynamicprocedure.Diverterisavoided,weightofchosenmassstandardsisreplacedbythesameamountofwaterduringthemeasuringtime.Forthispurposethereadoutfrequencyoftheweighingcellsisincreasedupto40Hz,Whereaseachreadoutofeachcellistime-stampedwithinanuncertaintyoflessthan0,7ms.Toavoidinfluencesfromthermallydrivenairflowinmeasurementhall,itisplannedtobuildupatemperaturestabilizedcontainmentforthewholeweighingsystem.天大泰和德国德国国家计量院国家计量院（PTB）http:

/www.ptb.de/index_en.htmlPTBisthenationalmetrologyinstitute;highesttechnicalauthorityundertheFederalMinistryofEconomicsandTechnologyStaffs:

1800Structure:

Ninescientificandtechnicaldivisions,subdividedintomorethan100sectionsandprojectsAnnualbudget:

130millionEuroTasks:

Fundamentalsofmetrology,metrologyforeconomy,metrologyforsociety,internationalaffairsHistorical:

Foundedin1887http:

/www.ptb.de/index_en.htmlPTBisthenationalmetrologyinstitute;highesttechnicalauthorityundertheFederalMinistryofEconomicsandTechnologyStaffs:

1800Structure:

Ninescientificandtechnicaldivisions,subdividedintomorethan100sectionsandprojectsAnnualbudget:

130millionEuroTasks:

Fundamentalsofmetrology,metrologyforeconomy,metrologyforsociety,internationalaffairsHistorical:

Foundedin1887天大泰和PTBDivisions1.MechanicsandAcoustics2.Electricity3.ChemicalPhysicsandExplosionProtection4.Optics5.PrecisionEngineering6.IonizingRadiation7.TemperatureandSynchrotronRadiation8.MedicalPhysicsandMetrologicalInformationTechnology9.Scientific-technical：

Cross-sectionalTasks天大泰和Division1anddivision7:

1MechanicsandAcousticsDivision1.1Mass1.2SolidMechanics1.3Kinematics1.4GasFlow1.5LiquidFlow1.52：

NationalStandardforLiquidFlowMeasurement1.6Sound1.7AppliedAcoustics7Temperature&SynchrotronRadiation7.1X-rayMetrologywithSynchrotronRadiation7.2RadiometrywithSynchrotronRadiation7.3DetectorradiometryandRadiationThermometry7.4Temperature7.5CryophysicsandVacuumphysic7.6HeatWorkingGroup7.61：

ThermalEnergyMeasurementIB.TTechnisch-WissenschaftlicheInfrastrukturBerlin天大泰和WorkingGroup7.61C