1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS ISO 14139:2000 ICS 17.
2、120.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Hydrometric determinations Flow measurements in open channels using structures Compound gauging structuresThis British Standard, having been prepared under the direction of the Sector Committee for Materials and Chemicals,
3、 was published under the authority of the Standards Committee and comes into effect on 15 August 2000 BSI 08-2000 ISBN 0 580 36074 1 BS ISO 14139:2000 Amendments issued since publication Amd. No. Date Comments National foreword This British Standard reproduces verbatim ISO 14139:2000 and implements
4、it as the UK national standard. It supersedes BS 3680-4D:1989 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee CP/113, Hydrometry, to Subcommittee CPI/113/2, Notches, weirs and flumes, which has the responsibility to: aid enquirers to understand the te
5、xt; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. This standard states that it is mandatory to includ
6、e divide piers between adjacent sections of compound gauging structures. This recommendation was originally made because of a lack of information on the performance of structures without divide piers. Research has now been carried out on structures without divide piers and this research has shown th
7、at gross errors can arise if divide piers are omitted, thus confirming the original recommendation. A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in t
8、his document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Us
9、ers of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to iv, pages 1 to 41 and a
10、 back cover. The BSI copyright notice displayed in this document indicates when the document was last issued.Referencenumber ISO14139:2000(E) INTERNATIONAL STANDARD ISO 14139 Firstedition 2000-06-15 HydrometricdeterminationsFlow measurementsinopenchannelsusing structuresCompoundgauging structures Dt
11、erminationshydromtriquesMesurededbitdesliquidesdansles canauxdcouvertsaumoyendestructuresStructuresdejaugeage hybridesISO14139:2000(E) ii ISO14139:2000(E)iii Contents Page Foreword.iv 1 Scope1 2 Normativereferences1 3 Terms,definitionsandsymbols.2 4 Characteristicsofcompoundgaugingstructures.3 5 Ins
12、tallation4 5.1 Selectionofsite.4 5.2 Installationconditions.5 6 Maintenance.6 7 Measurementofhead7 7.1 General7 7.2 Stillingwell.7 7.3 Zerosetting8 7.4 Locationofheadmeasurementsection(s).8 8 Computationofdischarge8 8.1 Modularflowconditions.8 8.2 Non-modular(drowned)flowconditions9 9 Errorsinflowme
13、asurement.9 9.1 General9 9.2 Sourcesoferror.9 9.3 Kindsoferror.9 9.4 Errorsincoefficientvaluesanderrorsinmeasurement.10 9.5 Combinationsofuncertaintiestogiveoveralluncertaintyintotaldischarge10 9.6 Presentationofresults11 AnnexA(normative)Velocitydistribution.12 AnnexB(normative)Non-modular(drowned)
14、flow.14 AnnexC(normative)Methodsofcalculations.24ISO14139:2000(E) iv Foreword ISO(theInternationalOrganizationforStandardization)isaworldwidefederationofnationalstandardsbodies(ISO memberbodies).TheworkofpreparingInternationalStandardsisnormallycarriedoutthroughISOtechnical committees.Eachmemberbody
15、interestedinasubjectforwhichatechnicalcommitteehasbeenestablishedhas therighttoberepresentedonthatcommittee.Internationalorganizations,governmentalandnon-governmental,in liaisonwithISO,alsotakepartinthework.ISOcollaboratescloselywiththeInternationalElectrotechnical Commission(IEC)onallmattersofelect
16、rotechnicalstandardization. InternationalStandardsaredraftedinaccordancewiththerulesgivenintheISO/IECDirectives,Part3. DraftInternationalStandardsadoptedbythetechnicalcommitteesarecirculatedtothememberbodiesforvoting. PublicationasanInternationalStandardrequiresapprovalbyatleast75%ofthememberbodiesc
17、astingavote. AttentionisdrawntothepossibilitythatsomeoftheelementsofthisInternationalStandardmaybethesubjectof patentrights.ISOshallnotbeheldresponsibleforidentifyinganyorallsuchpatentrights. InternationalStandardISO14139waspreparedbyTechnicalCommitteeISO/TC113,Hydrometricdeterminations, Subcommitte
18、eSC2,Notches,weirsandflumes. AnnexesAtoCformanormativepartofthisInternationalStandard.INTERNATIONALSTANDARD ISO14139:2000(E)1 HydrometricdeterminationsFlowmeasurementsinopen channelsusingstructuresCompoundgaugingstructures 1 Scope ThisInternationalStandardspecifiesthemethodsofmeasurementofflowinrive
19、rsandartificialchannels,using anycombinationofstandardweirsand/orflumesinacompoundstructure.Forguidanceontheselectionofweirs and/orflumes,refertoISO8368.Allstructurescanbeoperatedinthemodularflowrange,butonlyalimited numberofstructurescanbeusedinthedrowned(non-modular)flowrange(seeclause4).Compoundw
20、eirs improvethequalityofdischargemeasurementsatlowstages. ThecharacteristicsofvelocitydistributionaredescribedannexA. Structuresstandardizedforoperationinthedrowned(non-modular)flowrangeandthemethodofcomputationof flowaredescribedinannexB. Methodsandexamplesofflowmeasurementcalculationsaregiveninann
21、exC. Compoundflow-measuringstructureswithoutdividepiersneedinsituormodelcalibrationsandarenotcoveredby thisInternationalStandard. 2 Normativereferences Thefollowingnormativedocumentscontainprovisionswhich,throughreferenceinthistext,constituteprovisionsof thisInternationalStandard.Fordatedreferences,
22、subsequentamendmentsto,orrevisionsof,anyofthese publicationsdonotapply.However,partiestoagreementsbasedonthisInternationalStandardareencouragedto investigatethepossibilityofapplyingthemostrecenteditionsofthenormativedocumentsindicatedbelow.For undatedreferences,thelatesteditionofthenormativedocument
23、referredtoapplies.MembersofISOandIEC maintainregistersofcurrentlyvalidInternationalStandards. ISO772:1996,HydrometricdeterminationsVocabularyandsymbols. ISO1438-1:1980,WaterflowmeasurementinopenchannelsusingweirsandVenturiflumesPart1:Thin-plate weirs. ISO3846:1989,Liquidflowmeasurementinopenchannels
24、byweirsandflumesRectangularbroad-crested weirs. ISO4359:1983,LiquidflowmeasurementinopenchannelsRectangular,trapezoidalandU-shapedflumes. ISO4360:1984,LiquidflowmeasurementinopenchannelsbyweirsandflumesTriangularprofileweirs. ISO4362:1999,HydrometricdeterminationsFlowmeasurementinopenchannelsusingst
25、ructures Trapezoidalbroad-crestedweirs. ISO4374:1990,LiquidflowmeasurementinopenchannelsRound-nosehorizontalbroad-crestedweirs. ISO4377:1990,LiquidflowmeasurementinopenchannelsFlat-Vweirs.ISO14139:2000(E) 2 ISO/TR5168:1998,MeasurementoffluidflowEvaluationofuncertainties. ISO8333:1985,Liquidflowmeasu
26、rementinopenchannelsbyweirsandflumesV-shapedbroad-crestedweirs. ISO8368:1999,HydrometricdeterminationsFlowmeasurementsinopenchannelsusingstructures Guidelinesforselectionofstructure. ISO9826:1992,MeasurementofliquidflowinopenchannelsParshallandSANIIRIflumes. ISO9827:1994,Measurementofliquidflowinope
27、nchannelsbyweirsandflumesStreamlinedtriangularprofile weirs. 3 Terms,definitionsandsymbols ForthepurposesofthisInternationalStandard,thetermsanddefinitionsgiveninISO772apply.Afulllistof symbolswiththecorrespondingunitsofmeasurementisgivenbelow. Symbol Unitsof measurement A areaofcross-sectionofflow
28、m 2 b crestwidth m B widthofapproachchannel m C D coefficientofdischarge non-dimensional C dr drowned-flowreductionfactor non-dimensional C v coefficientofapproachvelocity non-dimensional e uncertaintyinabsolutemagnitude non-dimensional g accelerationduetogravity m/s 2 h gaugedhead m H totalhead m h
29、 p crest-tappingpressurehead m h v velocityapproachhead m L lengthofflumethroatorweircrestindirectionofflow m n numberofmeasurementsinaset non-dimensional p heightofflumeinvertorweircrestabovemeanbedlevel m Q totaldischarge m 3 /s Q 1 ,Q 2 ,Q 3 individualsectiondischarges(ingeneralQ n )m 3 /s Q mod
30、totalmodulardischarge m 3 /s q dischargeperunitwidth m 3 /s s y standarddeviationofasetofmeasurementsofquantityy m y s estimatedstandarddeviationofthemeanofseveralreadings ofquantityy m v meanvelocityatcross-section m/s a v meanvelocityinapproachchannel m/s X Q percentageuncertaintyintotaldischarge
31、non-dimensionalISO14139:2000(E)3 X Q,1 ,X Q,2 ,X Q,3 1) percentageuncertaintyinindividualsectiondischarges non-dimensional X tu percentageuncertaintyinestimatingupstreamwaterlevelsor upstreamtotalheadlevels non-dimensional X td percentageuncertaintyinestimatingdownstreamwater levelsordownstreamtotal
32、headlevels non-dimensional X y percentageuncertaintyinquantityy non-dimensional Coriolisenergycoefficient non-dimensional differenceinweir-crestlevels m boundarylayerdisplacementthickness m Suffixes 1 denotesupstreamvalue 2 denotesdownstreamvalue Superscripts G referstogaugingsection T referstocrest
33、-tappingsection S referstoanyothersection 4 Characteristicsofcompoundgaugingstructures AcompoundgaugingstructureascoveredbythisInternationalStandardcomprisestwoormoreindividual structures,operatedinparallelandseparatedbydividepiers. Theindividualstructures,whichcanbeusedinacompoundgaugingweir,arespe
34、cifiedinISO1438-1,ISO3846, ISO4359,ISO4360,ISO4362,ISO4374,ISO4377,ISO8333,ISO9826andISO9827.Thestructuresdescribed inISO4360,ISO4362,ISO4377,ISO8333,ISO9826andISO9827maybeusedinthedrownedflowrange(see annexB.1). Inthemodularflowrange,dischargesdependsolelyonupstreamwaterlevels,andasinglemeasurement
35、of upstreamheadisrequired.Inthedrownedflowrange,dischargesdependonbothupstreamanddownstream waterlevels,andtwoindependentheadmeasurementsarerequired.Theseare: a)theupstreamhead;andeither b)theheadmeasuredinthecrest-tappingforatriangularprofileweir(twodimensionalorflat-Vforms); c)theheadmeasuredwithi
36、nthethroatofaParshallflume;or d)theheadmeasuredinthetailwaterfortheotherstructures. 1)Incaseswherethesubscriptofasymbolalsocontainsasubscript,itishousestyletowritethesecondsubscriptonthe sameline,afteracomma. Thus 1 Q X iswrittenX Q,1 .ISO14139:2000(E) 4 Theflowconditionsconsideredarelimitedtosteady
37、orslowlychangingflows.Theessentiallyparallelflowthrough thecompoundstructureisensuredbytheuseofdividepiers.Theflowisseparatedbythedividepiersintoeach individualweirorflume.Thedischargecanbedeterminedthrougheachindividualsectionbyasingleupstream headmeasurement,atonesectiononly,inthecaseofmodularflow
38、orbytwoindependentheadmeasurements,at onesectiononly,asrequiredfordrownedflowconditions.Thesummationofthedischargesthrougheachofthe sectionsprovidesthemeasurementoftotalflowwithinthechannel. 5 Installation 5.1 Selectionofsite Apreliminarysurveyshallbemadeofthephysicalandhydraulicfeaturesofthepropose
39、dsitetocheckthatit conforms(ormaybemadetoconform)totherequirementsnecessaryformeasurementusingtheweir. Particularattentionshallbepaidtothefollowingfeaturesinselectingthesiteoftheweir: a)theavailabilityofanadequatelengthofchannelofregularcross-section; b)theexistingvelocitydistribution; c)theavoidanc
40、eofchannelshavinggradientsgreaterthan0,4%; d)theeffectsofanyincreasedupstreamwaterlevelduetotheflow-measuringstructure; e)theconditionsdownstream,includingsuchinfluencesastides,confluencewithotherstreams,sluice-gates,mill damsandothercontrollingfeaturesthatmightcausedrowning; f) theimpermeabilityoft
41、hegroundonwhichthestructureistobefounded,andthenecessityforpiling,grouting orothersealinginriverinstallations; g)thenecessityforfloodbankstoconfinethemaximumdischargetothechannel; h)thestabilityofthebanks,andthenecessityfortrimmingand/orrevetmentinnaturalchannels; i) theclearanceofrocksorbouldersfro
42、mthebedoftheapproachchannel; j) theeffectsofwind. NOTE1 Windcanhaveaconsiderableeffectontheflowinariveroroveraweir,especiallyiftheselatterarewideandthe headissmallandtheprevailingwindisinatransversedirection. Ifthesitedoesnotpossessthecharacteristicsrequiredforsatisfactorymeasurements,itshallberejec
43、tedunless suitableimprovementsarepracticable. Ifasurveyofastreamshowsthattheexistingvelocitydistributionisregular,thenitshouldbeassumedthatthe velocitydistributionwillremainsatisfactoryaftertheweirhasbeenbuilt. Iftheexistingvelocitydistributionisirregularandnoothersiteforagaugeisfeasible,dueconsider
44、ationshallbe giventocheckingthedistributionaftertheweirhasbeeninstalledandtoimprovingit,ifnecessary. NOTE2 Severalmethodsareavailableforobtainingmorepreciseindicationsofirregularvelocitydistribution:velocityrods, floatsorconcentrationsofdyecanbeusedinsmallchannels,thelatterbeingusefulincheckingcondi
45、tionsatthebottomofthe channel.Acompleteandquantitativeassessmentofvelocitydistributionmaybemadebymeansofacurrentmeter. NOTE3 Afterinstallation,thevelocityprofileswillalwaysbeimprovedbytheincreaseddepthofwaterapproachingthe compoundweir.ISO14139:2000(E)5 5.2 Installationconditions 5.2.1 General Theco
46、mpletemeasuringinstallationconsistsofanapproachchannel,aflow-measuringstructureanda downstreamchannel.Theparametersofeachofthesethreecomponentsaffecttheoverallaccuracyofthe measurements. Installationrequirementsincludesuchfeaturesasweirfinish,thecross-sectionalshapeofthechannel,channel roughnessandt
47、heinfluenceofcontroldevicesupstreamordownstreamofthegaugingstructure. Thedistributionanddirectionofvelocityhaveanimportantinfluenceontheperformanceofaweir,thesefactors beingdeterminedbythefeaturesmentionedinthissubclause. 5.2.2 Approachchannel Forallinstallations,theflowintheapproachchannelshallbesm
48、ooth,freefromdisturbanceandshallhavea velocitydistributionasnormalaspossibleoverthecross-sectionalarea(seeannexA);thiscanusuallybeverified byinspectionormeasurement.Inthecaseofnaturalstreamsorrivers,thisflowcanonlybeattainedbyhavinga long,straightapproachchannelfreefromprojectionsintotheflow.Unlesso
49、therwisespecifiedintheappropriate clausesofthisInternationalStandard,theapproachchannelshallcomplywiththegeneralrequirementsoutlinedin thissubclause. Thealteredflowconditionsduetotheconstructionoftheweirmayhavetheeffectofbuildingupshoalsofdebris upstreamofthestructure,whichintimemayaffecttheflowconditions.Thelikelyconsequentialchangesinthe waterlevelshouldbetakenintoaccountinthedesignofgaugingstations. Inanartificialchannel,thecross-sectionshallbeuniformandthechannelshallbestraightforalengthequaltoat leastfivetimesitswidth,andmoreifattainable. Inanatu
