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
Serial Year
2005
Journal title
Nuclear Engineering and Design Eslah
Record number
894871
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