ThereareseveralcaseswhichcanonlybemodelledbygeneralFEsoftware.Thisincludes:(1)Localizedloadsfromothermechanicaldevicessuchastensioners,caterpillars,clampsetc;(2)Bendstiffenerandendfittingdetails;(3)Redistributionofstressesduetowirefailures;(4)Bucklingeffe...[繼續(xù)閱讀]

    Forpipelines,theflowcharacteristicsincombinationwithheatandpressurelossesdeterminesthetemperatureandinternalpressureprofilesalongthepipe.Following,thecommissioningphase,theflowwillstarttoheatthepipeline,firstattheinletendthengraduallyalongthepipeline.Prov...[繼續(xù)閱讀]

    Incylindricalcoordinates,theheatconductionequationcanbewrittenas:where:Tisthetemperature(K);ristheradialcoordinate(m);xisthelongitudinalcoordinate(m);ψisthecircumferentialcoordinate(rad);istheheatgeneration;ρisthedensity;Cpisthespecificheatcapacit...[繼續(xù)閱讀]

    Attheouterandinnersurfacesheattransporttakesplacebyconvection.Theconvectionratewilldependontheflowphysicalpropertiesandthevelocitygoverningtheboundarylayerthicknessattheinterfaces.Theheatfluxthroughbothlayersisdefinedas:Qr＝2πrihi(Ti-Tl)=2πroho(Tn-To)(5.7)...[繼續(xù)閱讀]

    Flowlinesarenormallyburiedintosoilbothtoimprovetheinsulationpropertiesandtoprovidemechanicalprotection.Thisgivesextracontributiontotheinsulationsothatthetotalheattransfercoefficientcanbeexpressedas:wherezistheburialdepthtothepipecentre....[繼續(xù)閱讀]

    Assumingsteadystateconditions,axi-symmetricheatflowandconstantinternalpressure,thetemperatureprofilecanbeobtainedbyconsideringtheheatfluxinandoutofaninfinitesimalpipesegmentasshowninFigure5.3.Figure5.3HeatfluxinsmallpipesegmentWithreferencetoEq.5.5theneth...[繼續(xù)閱讀]

    Duringshut-downsthewellflowstopsandthepipewillstarttocooldown.Ifitisassumedthatthepipeisinsulatedbyathinefficientlayerofinsulationsothatmostoftheheatisstoredinsideoftheinsulation,thetimeuntilacriticaltemperaturecanbeestimatedbytheapproachshowninFigure5.4w...[繼續(xù)閱讀]

    Theoverallbasisforpipelinematerialselectionistoensureeconomicandsafeproducttransport.Duringthepipelinedesignphases,thematerialengineeringincludesdifferentactivitieswheretheconceptualdesignphasenormallyfocusonidentifyingthematerialrequirementsintermsof:(1)...[繼續(xù)閱讀]

    Thebasicquestionrelatedtocostsistoidentifywhethercarbonsteelcanbeusedornot.Inmanycasescarbonsteelcanbeappliedevenincorrosiveenvironments.However,thisrequirescalculationofcorrosionratesandtherequiredcorrosionallowance(CA).Corrosionallowanceistheamountofpip...[繼續(xù)閱讀]

    Weldingisafabricationprocessthatjoinsmaterials,usuallymetalsorthermoplastics.Themainideaistobondthesurfacestogetherbyliquefyingthematerialsurfacesandthereafterallowingtheliquidtosolidify.Attheendofthisprocessthetwopiecesofmaterialhavebecomeonecontinuousso...[繼續(xù)閱讀]