给排水工程外文翻译.docx

给排水工程外文翻译.docx

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给排水工程外文翻译

ShortandLongTermAdvantageroofdrainagedesignperformance

Decadehaswitnessedgreatchangesinthedesignoftheroofdrainagesystemrecently,particularly,siphonrainwaterdrainagesystemhasbeengraduallyimproved,andthereislikelytobethekeyapplication.Atthesametimethesechanges,urbandrainagesystemdesignhasundergonetremendouschanges,becausethescopeofawiderurbandrainagesystemdesignforsustainabledevelopment,aswellaspeopleforclimatechangefloodingmoreattention.Themaincontentsofthisarticleishowtodesignroofdrainagesystemsandmakeagoodperformance.Specialattentionishowtogetridofbadhabitsalreadyformedthedesign,butalsoneedtoconsiderinnovativeroofdrainagesystem,suchasgreenroofsandrainwaterharvestingsystems.

Practicalapplication:

Inthepastfewyears,thedesignoftheroofrainwaterdrainagesystemhasundergonetremendouschanges.Onlargebuildings,siphonrainwaterdrainagetechnologyhasbeenverycommon,aswellasgreenroofsbecauseitisconducivetogreendevelopment,beingmoreandmoreapplications.Takingintoaccounttheongoingresearch,thisarticlefocusesonhowtoeffectivelydesignavarietyofroofrainwaterdrainagesystem,andmakeitachievethedesireddesigneffect.

1.Introduction

Inthepastdecade,thecityandthewaterdrainagesystemdesignhasbeenwidelyacceptedthinkingaboutsustainableurbandrainagesystem,ortheoptimalmanagementdirection.Themainprinciplesofthedesignofthesesystemsisbothalocallevelinlinewiththequalityofdevelopment,butalsotocreatesomeeconomicbenefitsfortheinvestors.Thisprinciplehasledtothedevelopmentofnewchangesinthesump.Althoughtheapplicationofsuchadeviceisgraduallyreduced,buttheurbanenvironmentrelativelyhighdemandareasstillrequire100%waterproofandrapiddrainage,suchastheroof.Typicallyroofdrainagesysteminthedesign,constructionandmaintenancehasnotbeengivendueattention.Althoughthedrainagesysteminvestmentcostsaccountforonlyasmallportionofthetotalconstructioninvestment,butnotabletojudgethelosscausedbypoordesign.

Therearetwodifferentformsofroofdrainagesystemdesignmethods,namelythetraditionalandsiphonmethod.Traditionalsystemsrelyonatmosphericpressurework,thedriveramaffectedsinkflowdepth.Therefore,theconventionalroofdrainagesystemsrequirearelativelylargediameterverticaldroptube,priortodischarge,alldevicesmustbeconnectedtothegroundwatercollectionpipenetwork.Incontrast,siphonicroofdrainagepipesystemsaregenerallydesignedtofullflow（turbulentflowmeansthatrequirelessexhaustpipe）,whichwillformanegativepressure,thelargerthehigherflowrateandpressurehead.Typicallysiphonsystemrequireslessdownpipeworkundernegativepressuretothewaterdistributionnetworkcanmeanhigheraltitudework,therebyreducingtheamountofundergroundpipenetwork.

Bothsystemsconsistsofthreeparts:

theroof,rainwatercollectionpipes,pipenetwork.

Alloftheseelementsareabletochangethewaterpressuredistributionsystem.Thissectionfocusesontheroleandperformanceofeachpart.Duetotheprincipleofsiphonsystemhasnotbeenwellunderstood,resultingargumentisrelativelysmall,thisarticlewillhighlightsiphonsystem.

2.Roof

Theroofisusuallydesignedbythearchitect,designerandnotbythedrainagedesign.Therearethreemainroof.

2.1Flatroof

Flatroofsareusedinindustrialbuildingslessrainfallregionsandcountries.Thisroofisnotcompletelyflat,butlowerthantheminimumroofslopemayrequire.Forexample,theUnitedKingdomrequiremaximumslopeof10°.Settingminimumslopeinordertoavoidanyunnecessarywater.

Despitetheflatroofifitisnotproperlymaintainedwillhavemoreproblems,butitwillreducethedeadzonewithinthebuilding,andtheratioofslopingroofsinfavorofindoorair.

2.2slopingroofs

Mostresidentialandcommercialbuildingsarepitchedroof,inclinedroofisthebiggestadvantagecanquicklydrain,therebyreducingleakage.Intemperateregions,weneedtoconsidercarryingroofsnowload.Onceitrains,rainfallthroughtheslopingroofscanbedeterminedbycalculation.Whenrainfalldatacanbeused,youcanusethekinematictheorytosolvesuchproblems.

2.3greenroof（flatorinclined）

Itcanproveroofistheoldestgreenroofs,includingrainfallcanreduceordisperseroofplantedwithplants.Itcanbeplantedwithtreesandshrubsroofgarden,itcanalsobeavegetatedrooflightcarpet.Whereinthelattertechniquehasbeenwidelyused.Someoftheseapplicationstendtofocusonaestheticrequirementsandareoftenusedingreendevelopment.Sincetheaestheticrequirementsandpressurerequirements,aswellasgreenroofsthermalinsulationfunction,reducetheheatislandeffect,silencereffect,extendthelifeoftheroof.

GreenroofsinGermany,themostwidelyused,followedinNorthAmerica,buttoconsidertheimpactontheaesthetics.Germanyisbyfarthemostexperiencedcountriesinthe19thcenturyhavepracticalapplication,thenasanalternativetoreducetheriskoffiretarroofanoptioninurbanareas.Germanyiscurrentlythemainresearchquestiononthecultivationofotherissuestoconsidersmallercities.Astudyfrom1987to1989,wasfoundpackedwith70mmthickgreenroofcanbereducedby60%-80%ofheatloss.InaCanadianworkcomputermodelbasedontheroofindicatesthataslongasthesump,theareacanreach70%oftheroofareacanbereducedby60percentinoneyear,thesamemodelwasalsousedforartificialrainfall,whichtheresultsindicatethatrainfallinthecatchmentseasonhelpstodrainawayrainwater.

However,noneofthesestudiesshowthatgreenroofscanplayausefulroleintherainfallseason,orhowhighcollectionefficiencyofwatersupply.TheUnitedStatesdidsometests,aslongasthegreenroofsregularwatering,canreduce65percentoftherunoffinarainfall.America'smostauthoritativegreenroofguidelinesbytheNewJerseystateenvironmentalagenciespromulgated.Themainprincipleistosolvethestructuralproblemsoflight,andhowcanthenormaldrainageaftertwoyears.

Rainfallperiodisbasedontheprobabilityoffailureisdetermined.Thesystemistypicallybasedonrainfallduringrainstormstwominutes,twominutes,haveachoice.Althoughthismodelwillgetmoretraffic,butthereisnootherbetteralternative.Studieshaveshownthatthetraditionalmodelisappliedtostudygreenroofsarepremature.

Lossfactorthantraditionalroofrecordsshouldbesmall,about98.7%.

Peakflowwillbereduced,althoughnotpenetrate,thesurfaceroughnessbutalsohaveasignificantimpact.

Concentratedrainfallthantwominutesforalongtime,especiallyforlargeroofareas,suchaspublicbuildings,commercialbuildings,industrialbuildings.

Urbandrainagedesignshouldalsoconsiderotherfactors,foracomplexsystem,agreenroofinarainisnotenough.Waterflowdurationcurveshowsalongerthantraditionalsystems.Andtwoindependentandwillaffectbetweenispossible,whichrequiresamoreprecisetimeperiod.

3.RainwaterCollector

Basicrequirementsrainwatercollectorisdesignedtobeabletoaccommodaterainfallrainstorms.Althoughitispossibletomakeaslightlyinclinedroofdrainagepurposes,butthenatureoftheconstructionindustryandbuildingsettlementwillbecomeflatroofTypically,thetankisplacedinahorizontal,sectionalviewofthewaterisoutwardlyinclined,whichtheroleofhydrostatic.

3.1drainoutlet

Analyzingrainwatercollectorhassufficientvolumeisthekeytothesumpoutletexternalsettingconditions.Alsoaffecttheflowrateintothestormwaterdrainagesystempiping,butalsoaffectthedepthofthewatercatchment.Althoughthedepthofthesumpwillnotbringanyparticularproblems,buttoodeepcancauseexcessivesump.

Numerousstudiesinthe1980sshowedthattheflowofconventionalroofdrainagesystemoutletcanbedividedintotwocases.Itdependsonthesizeofthedepthandsizeoftheoutlet.Whenthewaterdepthislessthanhalfthediameteroftheoutlet,theflowofthefirsttype,andtheoutletoftheflowcanbecalculatedbyanappropriateequation;waterdepthincreases,exportsareslowlycloggingtheflowwillbecomeanotherformforms,atthesametime,theflowofexportscanbeobtainedthroughotherequations.Whileconventionalroofdrainagesystemsaredesignedtobefree-draining,butmaycauselimitationsencounteredinthedesignoftheflowisnotfree.Inthiscase,itwillrequireadditionaldepth.

Siphonroofdrainagesystems,theoutletisdesignedtobesubmergedstream.Inthiscase,thedepthoftheoutletofthedecisionismorecomplicated,becausethedesignofthesumpdependsontheflow.Recentstudieshaveshownthatconventionalroofdrainagesystemsuseavarietyofnon-standardcatchment,theirdepthandheight,biggerthanthediameteroftheoutlet.Thiswilleventuallyresultinasiphoneffect.Foragivencatchment,theflowdependsonthestartingendofthedroptubediameter.Asimilarphenomenonhasalsobeenusedtostudythestandardcatchment,inthesecircumstances,onlylimitedsiphonactionoccurswithinrelativelyclosedistancefromtheexit.

3.2tankflowclassification

Inthecomplexflowsumpoutletflowclassification,canbeseenfromTable2a,theflowwillbeuniformlayering,regardlessofwhetherthesameinletflow.Table2band2cshow,exportdistributionwillgreatlyinfluencetheflow.

Whentheoutletisnotafreejet,sumpoutletcomplexflowclassificationisdifficulttodescribe.Becauseeachcatchmenttankpressures