Record number :
894871
Title of article :
Hydro-thermal-mechanicalanalysisofthermalfatigueinamixingteeOriginalResearchArticle
Author/Authors :
S.Chapuliot، نويسنده , , C.Gourdin، نويسنده , , T.Payen، نويسنده , , J.P.Magnaud، نويسنده , , A.Monavon، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2005
Pages :
22
From page :
575
To page :
596
Abstract :
ThispapercoversworkcarriedoutbytheCEAtostudythemechanismsleadingtocrackingofpipingasaresultofthermalloadinginflowmixingzones.Themaingoaloftheworkistoanalyse,bycalculation,thethermalloadingcausedbyturbulentmixinginteesandtounderstandthemechanismofinitiationandpropagationofcracksinsuchcomponents.ThisworkissupportedbyIRSN.Thisthermalfatiguephenomenonisstillnotfullyunderstood.Oneofthemainobstaclestoitsunderstandingresidesinthemulti-domainnatureoftheloadingandassociateddamage,involvingthreecomplementaryscientificdisciplines:thermal-hydraulicfield,thermo-mechanicalfieldandmaterialsscience. ThispaperdescribestheapproachadoptedbytheCEAtoestablishnaturalmechanisms(turbulence,pulsingandinstability)whichmightbethecauseofanysubstantialthermo-mechanicalloadinginthepiping. Althoughturbulencemaybethecauseofthethermalstripping(presenceofhigh-frequencythermalfluctuationsontheinnersurfaceofthecomponent),itcannotaloneexplainthepropagationofdeepcracks.Themainreasonisthe“high-passfilter”effectofconvection.Thewallcannotbesubjectedtoconvection-relatedthermalfluctuationsandfrequencieslessthantheinverseoftheturbulencetransittime.Astraightforwardfrequency-basedanalysisoftheloading,carriedoutasafirststage,madeitpossibletoestablishthelimitsoftheloadingcreatedbythesehigh-frequencyevents. However,turbulencecangiverisetoflowinstability(suchaspulsing)oflowerfrequency.Butthiscannotexplaineverything.Thegeometryupstreamofthetee,particularlythesequenceofstraightsectionsandbendscan,incertaincases,dampthepulsesorgreatlyamplifythem.Theuseofsuitablethermal-hydraulicmodellingisdiscussedinthesecondpartofthisarticle. Thefinalresultofthethermo-hydro-mechanicallink-uponapplicationtothecomplex3DgeometryoftheCivauxunit1case(whichincludesamixingtee,bendsandstraightsections)enabledtheobservationsmadeinthisplantcasetobehighlightedandcorrelated.Oneoftheoriginalitiesofthisstudyistocarryouttheoverallanalysis(thermal-hydraulicandthermo-mechanical)withasinglecomputercode,theCAST3McodedevelopedbytheCEA.
Journal title :
Nuclear Engineering and Design Eslah
Journal title :
Nuclear Engineering and Design Eslah
Serial Year :
2005
Link To Document :
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