给排水工程专业外文翻译Word文件下载.docx

给排水工程专业外文翻译Word文件下载.docx

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Inaddressingsustainabilityissuesforthebuiltenvironment,focusisoftendirectedtowardsminimisingenergyconsumptionandmaterialuse.Oftenforgottenhowever,isthepotentialfortheintegrationofsustainablesolutionswhendesigningwaterandwastemanagementsystemsforbuildings.Thefundamentalfunctionsofsuchsystemsareclearlyrecognised,buttraditionaldesignprinciplesoftenconstrainopportunitiesforperformanceenhancementandforwaterandpipeworkeconomies.Toanextent,thisisunsurprising,giventhebasicpremisethatsteady-stateanalysisofflowsunderpinsmanyofthecodesandguidelinesusedworldwide.However,advancesinsimulationmethodsmeanthatsystemperformanceresultingfromtheuseofnewtechniquesandfromtheintegrationofinnovativeandmoresustainabledesignapproachescannowbefullyassessed.Thispaperprovidesanoverviewofthewatersupplyanddrainagesystemsforbuildingswhoseperformancehasbeenassessedthroughthedevelopment,atHeriot–WattUniversity,ofasuiteofnumericalsimulationmodels.Thesemodelsaccuratelypredict,usingappropriateformsoftheSt.Venantequations,thepressureandflowregimewithinsuchsystemsbyapplyingtheMethodofCharacteristicsfinitedifferencetechnique.Thepaperprovidesthreedifferentexamplesofapplication,wherethefocusofeachisonembeddingsustainabilityindesign.

1.Introduction

Inprovidingwatersupplyandwastemanagementsystemsforbuildings,itisessentialthatperformanceisassured.Keyfunctionsencompass:

theprovisionofpotablewaterandthatrequiredforbasichygiene;

theremovalofwaterthathasbeencontaminatedwithwasteproducts;

andtheprovisionofaphysicalbarrierbetweenthepotentiallyharmfulmiasmapresentindrainpipesandsewersandthehabitablespace.Itisalsoimportantthatthebuildingusestobestbenefit,anyimpingingrainwateraswellasanyresultantwastewater,thusreducingunnecessarywastageandlimitingtheloadingonseweranddrainagenetworksand/orcollectionsystems.Sustainabilityshouldunderpindesigntheoryineachoftheseaspectsthroughlimitingwatersupplyandconsumption,andthroughreducingmaterialuse,costandenvironmentalimpact.Watersupplyanddrainagesystemsforbuildingsthereforeprovideanumberofopportunitiesfortheintegrationofsustainablesolutions,however,thesemustbeachievedwithoutcompromisingperformance,andthus,theresponseofsystemsduringusemustbefullyunderstood.

Oftentheapproachadoptedforthedesignofwaterandwastewatersystemsisbasedupontheapplicationofsteady-stateprinciplesinordertodetermine,forexample,flowloadingorpressureresponse.Althoughsuchmethodsfacilitatesystemspecificationinasomewhatdeterministicfashion,theyseldomprovidetheopportunitytoassessthetime-dependentresponseofsystems–informationthatcanreadilyinformkeydesigndecisions.Thefollowingtextwillthereforeillustratehowanunderstandingofthedynamicresponseofsystemscoupledwiththedevelopment,atHeriot–Watt,ofasuiteofnumericalsimulationmodelshasfacilitatedtheeffectiveandefficientdesignandanalysisofwatersupplyanddrainageforbuildings,therebyenablingacomprehensiveassessmentofthepotentialforintegrationofinnovativeandsustainabledesignsolutions.Itisworthnotingatthispointthat,throughoutthispaper,theterm‘watersupply’willbepresentedwithinthecontextofwaterusewithinthebuildingthat,indirectly,dictatessupplyfromlargescalenetworks.

EachcomponentmodelcontributingtothesuitedevelopedatHeriot–WattutilisestheMethodofCharacteristicstechnique.ThistechniquewasfirstusedbyMassauin1900toanalyseopenchannelflow,andthenbyLamoenin1947toanalysewaterhammer,andtransformstheappropriateformsoftheSt.Venantequationsofcontinuityandmomentumintoapairoftotaldifferentialequationssolvablebyfinitedifferencemethods.TheseequationsaretermedtheC+andC−characteristics,anddefinetheconditionsatanodeonetimestepinthefutureintermsofcurrentconditionsatadjacentupstreamanddownstreamnodes.Thefinitedifferencegridisdefinedusingtheindependentvariablesdistance,xandtime,t,linkedwithdependentvariables,eitheruandc–fluidvelocityandpropagationwavespeedforairoruandh–fluidvelocityanddepthforfreesurfacewater.Itwillbeappreciatedthatatsystemboundaries,anadditionalequationisrequiredtocompletethefinitedifferencesolution.Equationsarethereforedefinedattheselocations,andprovideinformationonthestaticordynamicbehaviour,asappropriate,oftheboundary.

ThetheoreticalandempiricaldefinitionoftheseboundaryconditionequationshasformedthefocusofbothpastandpresentresearchatHeriot–Watt,andhasfacilitatedthedevelopmentofthethreecomponentmodelsreferredtointhistext–DRAINET,AIRNETandROOFNET.AllthreearebasedontheMethodofCharacteristicstechniquedescribed,andeachhasbeensuccessfullyusedtoenhancethedesignapproachforrelevantsystems.DRAINETdealswiththetransientanalysisofpartiallyfilled,i.e.freesurface,pipeflow,predominantlyaddressingtheperformanceofinternalbuildingdrainagesystems.Itsapplicationhasrecentlybeenextendedtoencompasslocalexternaldrainagesystemswheretheflowregimemaystillbecharacterisedbywaveattenuation.AIRNETexaminesthetransientresponseofdrainageventilationsystems,bypredictingthepressureandairflowthatinfluencestheintegrityofthewater-basedappliancetrapseal,whereasROOFNET

assessestheperformanceofbothconventionalandsiphonicrainwaterdrainagesystemsforbuildings.Itwillbeappreciatedthat,toanextent,ROOFNETandDRAINETcanbeoperatedjointlytofacilitatethepredictionofrainwaterconveyancefromroofsurfacesthroughtolocaldrainagesystems.Thispaperwillillustrate,throughtheuseofexamples,howthesemodelcomponentsmaybeappliedtointegrateandembedsustainabilityinthedesignofwatersupplyanddrainagesystemsforbuildings.

2.Potablewateruseandtheimpactofreducingw.c.flushvolumes

Thedefinitionofsustainabilitymay,andoftendoes,differdependinguponthecontextwithinwhichitisset.Formanydevelopedcountries,sustainabilityfocusesonreducingoroptimisingtheuseof,forexample,energyormaterials,whereasinotherregions,sustainabilityismoreaboutthestableprovisionofbasicneeds.Withinthelattercontext,andsetagainsttheUN'

sMillenniumDevelopmentGoals,onekeyaim（conveyedintheUN'

sTaskForceonWaterandSanitation）isto‘halve,by2015,theproportionofpeoplewithoutsustainableaccesstosafedrinkingwaterandbasicsanitation’[1].Itthereforeseemscounterintuitivethatinmanycountries,asignificantproportionofthepotablewatersupplytobuildingsisusedforw.c.flushing.Thedirectcostsavingsassociatedwithanyreductioninw.c.flushvolumethatarisefromtreatmentprocessesaloneareclearlysignificant,andwhencoupledwithindirectsavingsfacilitatedbyareductioninpipesizeforbothsupplyanddrainagesystems,increaseyetfurther.

Proposalstointroduceanysignificantreductioninw.c.flushvolumehowever,areoftenmetwithconcernsovertheefficiencyoftheremovalofwasteandotherproductsfromsanitaryappliances,andoftheirconveyancethroughassociateddrainagenetworks.IntheUK,aflushvolumeof40lhadbeenrecognisedasexcessiveasearlyasaround1900,howeverfollowingadramaticreductionto9.1l（2gallons）,itthentookanumberofdecadesbeforeanyfurthersignificantreductionswereimposed.Statutoryregulations,implementedby2001[2],nowstipulate,forinstallation,amaximumflushvolumeof6landareducedflushvolumenotgreaterthantwothirdsofthemaximum,therebytargetingtheseeminglydisproportionatelevel

ofaroundonethirdofdomesticwatersupplycurrentlyusedforw.c.flushing[3].

Assuminganywasteproductsareeitherorganicorthattheycomplywithacceptedflushabilitycriteria,thefocusthereforeshiftstotheperformanceofthepipeworkthatconveysthiswastetoadownstreamdrainorsewer.Theflowregimeinthepipeworkservingthesanitaryapplianceisinherentlyunsteady,andtherehasbeenasubstantialbodyofworkundertakenatHeriot–Wattandelsewhere,withtheaimofpredictingtheimpactofdesignchangesand/orchangesinwaterconsumptionuponthedrainlinecarryofdiscretesolids.Beingabletopredictthelocationofsoliddeposition,andbeingabletotakepreventativeaction,clearlyavoidsthepropensityforblockage.

Thefollowingtextpresentsastraightforwardexampleofhowtheperformanceofpipework,whensubjectedtovariablew.c.dischargevolumes,canbeassessedusingDRAINET.Inthiscase,thedischargevolumefromtheapplianceshownconnectedtoPipe2,Fig.1,hasbeenvariedbetween9,6,4.5and3l.EachofthefourflushvolumesselectedwasrepresentedusingaprofileofthetypealsoshowninFig.1.Inthisexample,thetimeatwhichthesolidleavestheappliancewasvariedappropriatelytoensurethat,inallcases,thisprecededthepointatwhichpeakflowdischargeoccurs.Thisisimportant,asitiswellknownthatinadditiontodischargeprofile,solidparameters,andpipeslope,diameter,roughnessand‘base’flow,thesoliddischargetimerelativetotheoverallflushduration（i.e.therebydefiningthe‘trailingvolume’）hasasignificantinfluenceondrainlinecarry（whereearlysolidremovalensuresagreatertraveldistance）[4].

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