ThereareseveralcaseswhichcanonlybemodelledbygeneralFEsoftware.Thisincludes:(1)Localizedloadsfromothermechanicaldevicessuchastensioners,caterpillars,clampsetc;(2)Bendstiffenerandendfittingdetails;(3)Redistributionofstressesduetowirefailures;(4)Bucklingeffe...[继续阅读]

    Forpipelines,theflowcharacteristicsincombinationwithheatandpressurelossesdeterminesthetemperatureandinternalpressureprofilesalongthepipe.Following,thecommissioningphase,theflowwillstarttoheatthepipeline,firstattheinletendthengraduallyalongthepipeline.Prov...[继续阅读]

    Incylindricalcoordinates,theheatconductionequationcanbewrittenas:where:Tisthetemperature(K);ristheradialcoordinate(m);xisthelongitudinalcoordinate(m);ψisthecircumferentialcoordinate(rad);istheheatgeneration;ρisthedensity;Cpisthespecificheatcapacit...[继续阅读]

    Attheouterandinnersurfacesheattransporttakesplacebyconvection.Theconvectionratewilldependontheflowphysicalpropertiesandthevelocitygoverningtheboundarylayerthicknessattheinterfaces.Theheatfluxthroughbothlayersisdefinedas:Qr＝2πrihi(Ti-Tl)=2πroho(Tn-To)(5.7)...[继续阅读]

    Flowlinesarenormallyburiedintosoilbothtoimprovetheinsulationpropertiesandtoprovidemechanicalprotection.Thisgivesextracontributiontotheinsulationsothatthetotalheattransfercoefficientcanbeexpressedas:wherezistheburialdepthtothepipecentre....[继续阅读]

    Assumingsteadystateconditions,axi-symmetricheatflowandconstantinternalpressure,thetemperatureprofilecanbeobtainedbyconsideringtheheatfluxinandoutofaninfinitesimalpipesegmentasshowninFigure5.3.Figure5.3HeatfluxinsmallpipesegmentWithreferencetoEq.5.5theneth...[继续阅读]

    Duringshut-downsthewellflowstopsandthepipewillstarttocooldown.Ifitisassumedthatthepipeisinsulatedbyathinefficientlayerofinsulationsothatmostoftheheatisstoredinsideoftheinsulation,thetimeuntilacriticaltemperaturecanbeestimatedbytheapproachshowninFigure5.4w...[继续阅读]

    Theoverallbasisforpipelinematerialselectionistoensureeconomicandsafeproducttransport.Duringthepipelinedesignphases,thematerialengineeringincludesdifferentactivitieswheretheconceptualdesignphasenormallyfocusonidentifyingthematerialrequirementsintermsof:(1)...[继续阅读]

    Thebasicquestionrelatedtocostsistoidentifywhethercarbonsteelcanbeusedornot.Inmanycasescarbonsteelcanbeappliedevenincorrosiveenvironments.However,thisrequirescalculationofcorrosionratesandtherequiredcorrosionallowance(CA).Corrosionallowanceistheamountofpip...[继续阅读]

    Weldingisafabricationprocessthatjoinsmaterials,usuallymetalsorthermoplastics.Themainideaistobondthesurfacestogetherbyliquefyingthematerialsurfacesandthereafterallowingtheliquidtosolidify.Attheendofthisprocessthetwopiecesofmaterialhavebecomeonecontinuousso...[继续阅读]