Transient Turbulent Flow in a Liquid Metal Model of Continuous Casting Including Comparison of Six Different Methods

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1、TransientTurbulentFlowinaLiquid-MetalModelofContinuousCasting,IncludingComparisonofSixDifferentMethodsR.CHAUDHARY,C.JI,B.G.THOMAS,andS.P.VANKAComputationalmodelingisanimportanttooltounderstandandstabilizetransientturbulentfluidflowinthecontinuouscastingofsteeltominimizedefects.Thecu

2、rrentworkcombinesthepredictionsoftwosteadyReynolds-averagedNavier–Stokes(RANS)models,a‘‘filtered’’unsteadyRANSmodel,andtwolargeeddysimulation(LES)modelswithultrasonicDopplervelocimetry(UDV)measurementsinasmall-scaleliquidGaInSnmodelofthecontinuouscastingmoldregionfedbyabifurcatedwe

3、ll-bottomnozzlewithhorizontalports.Bothmeanandtransientfeaturesoftheturbulentflowareinvestigated.LESoutperformedallmodelswhilematchingthemeasurements,exceptinlocationswheremeasurementproblemsaresuspected.TheLESmodelalsocapturedhigh-frequencyfluctuations,whichthemeasurementscouldnotd

4、etect.SteadyRANSmodelsweretheleastaccuratemethods.Turbulentvelocityvariationfrequenciesandenergiesdecreasedwithdistancefromthenozzleportregions.Properorthog-onaldecompositionanalysis,instantaneousvelocitypatterns,andReynoldsstressesrevealthatvelocityfluctuationsandflowstructuresasso

5、ciatedwiththealternating-directionswirlinthenozzlebottomleadtoawobblingjetexitingtheportsintothemold.Theseturbulentflowstructuresareresponsibleforpatternsobservedinboththetimeaverageflowandthestatisticsoftheirfluctuations.DOI:10.1007/s11663-011-9526-1ÓTheMinerals,Metals&MaterialsSoci

6、etyandASMInternational2011I.INTRODUCTIONlowerregionofthemold.Interactionoftheflowfromthetwosidesofthemoldcausedlargevelocityfluctu-OPTIMIZATIONoffluidflowinthecontinuousationsnearthetopsurface.Ramos-Banderasetal.[9]castingprocessisimportanttominimizedefectsinsteelalsofoundthatLESmodel

7、predictionsagreedwellwithproducts.Turbulentfluidflowinthesubmergedentryinstantaneousvelocityfieldmeasurementsusingdigitalnozzle(SEN)andthemoldarethemaincausesofPIVinawatermodelofaslabcaster.Flowchangedentrainmentofslaginclusionsandtheformationof[1]significantlybecauseofverticaloscilla

8、tionsofthejet.surfacedefects.Comp