简介:UnderstandingthecomplexphenomenainBFhearthisessentialtoincreasefurnaceproductivityandtoextendfurnacecampaign.Wehavedevelopedseveralcontinuum-basedmathematical/numericalmodelstosimulatethemulti-phaseflow,heattransferandchemicalreactionsintheBFhearth.Thesemodelshavegeneratedanimprovedinsightonthemechanismsforliquiddrainageefficiency,liningerosionandwallprotectioninBFhearthunderoperationalconditions.Thecurrentpapergivesanoverviewofthesestudiesinthreeaspects:Gasflowandpressureontheliquidsurface,andtheireffectonthedrainagecharacteristics;TheflowandtemperaturedistributionsofliquidironinBFhearth,andthetemperaturedistributionintherefractories;Finally,titaniumbehaviorsduetotitaniainjectiontoformTi(C,N)-richscaffoldonthehearthsurface,toprotectthehearthfromerosion.
简介:Multiphaseflowcontrolwithelectromagneticbraking(EMBr)iswidelyusedinthecontinuouscastingofsteelslabs.Thebasicaimoftheflowcontrolsystemoftheprocessistodelivermoltensteelfromtheladlethroughthetundish,uppertundishnozzle,slidegate,andsubmergedentrynozzleintothemoldregionwithminimaldefects.Thisrequirestheoptimizationofturbulencelevelsatameniscustoavoidbothanexcessivelyfastflow(whichcreateshighfluctuationsofthemeniscuslevelinadditiontoslagentrapment,surfacenonuniformities,andsurfacedefects)andinsufficientslowflow(whichleadstomeniscussolidification,inadequatefluxinfiltration,andsurfacedefects).Inthisstudy,aEulerian-LagrangianapproachisusedtoinvestigatetheeffectsofEMBrandArbubbleinjectiononthesurfaceflowvelocity.TheresultsshowthathighArinjectionratescanleadtoanincreaseinsurfacevelocity.
简介:Inordertoimproveargonblowingefficiencyina40tonladle,numericalsimulationandwatersimulationexperimentsofthebottomargonflowwereperformed.Relationshipsamongtheladlemixingtime,slageyearea,differentblowingflowrates,anddifferentblowingpositions(0,0.56R,0.62R,0.67R)arediscussed.Resultsshowedthattheladlemixingtimedecreasedwhentheargonblowingbrickdistance(frombottomcenteroftheladle)increased,anddecreasedsignificantlywhentheblowingflowincreasedfrom70to130L/h.Whentheblowingflowincreasedandexceeded130L/h,thestirringeffecttendedtobestable,andtherewaslittleeffectontheladlemixingtime.Theslageyeareaincreasedastheargonbrickdistanceincreased,andwaslargerwhentheargonblowbrickwasneartheladlewall.Wallshearstresssignificantlyincreasedasthebrickdistanceincreasedandwasconcentratedattheslagwallneartheargonflowbrick;thisiscalledthemostseriouserosionwall.Theaveragewallshearincreasedexponentiallywithincreasingargonblowingbrickdistance.
简介:MaterialFlowAnalysis(MFA)isacrucialinstrumentforsustainabledevelopmentandcreatingindustrialecologysystem.MFAstudiescouldbalanceandanalyzethesources,flows,andconsumesofspecificmaterialsorsubstances.TheresultsofMFAstudiescouldsupportthestrategiesordecisionsmakingforenergy,resource,andwastemanagement,especiallyachievingsustainableresourcemanagement.AtCSC,thedynamicsimulatingsoftware,STELLA,isusedtodevelopaMFAmodelforscenarioanalysis.CSCalsousesthefreewareSTAN2.0asatoolforvisualizingandsimulatingmaterialflowsandstocks.CasestudiesofgreenhousegasesMFAforintegratedsteelworksareconducted.Theresultsshowedthatthecarboncontentofhot-metalisanimportanthiddenflowforbalanceanalysis,andthedifferentGHGemissionscenariosandmitigationactionscenariosareassessed.Inaddition,theIron-makingGHGI/OMFAModel,basedonworldsteelGlobalSteelSectorApproach(GSSA),isdevelopedforcalculatingtheCO2andenergyintensityofcokemaking,sintering,andBFprocesses.ThisMFAmodelwasusedtoanalyzetheCO2reductionpotentialforiron-makingprocess.ThecasesconductedforMFAapplicationsatCSCweresuchasgreenhousegas,zinc,etc.Inthefuture,CSCisgoingtodevelopa'CSCEnvironmentManagementandDecisionSupportingSystem'whichcombineMFA,LCA(lifecycleassessment),andenvironmentriskassessment.Thissupportingsystemexpectstopromotingenergyefficiencyandbestresourceuse,supportingenvironmentpolicymaking,creatingenvironmentalinformationvalue,etc.
简介:Inthisstudy,theeffectsofstandoffdistance(SoD)onthesupersonicflowfields(includinggasandparticleflowfields)duringcoldgasdynamicspraying(CGDS)areinvestigatedbymeansofcomputationalfluiddynamics(CFD).Thevariationofvelocity,temperature,pressureanddensitywithdifferentSoDiselucidatedthroughtheanalysisofthedistributionpropertiesoftheflowfields.Itisfoundthattheshockwavesinfrontofthesubstrateremarkablyinfluencethegasandparticleflowfields.Thewavesystemofexpansionwavesandpressurewavescomeintobeingcontinuously.ThevelocityofgasreachesthesupersonicspeedatthepositionoftheMachdisc,whileitdecreasessharplywhenthegasflowcrossestheMachdisc.TheoptimalSoDsare40mmfor1μmparticlesand50mmforboth5μmand22μmparticles.
简介:A0.02%Cplaincarbonsteelanda0.11%CNb-modifiedsteelweretestedincompressionintheaustenitetemperaturerange.Thecriticalstrainsfortheinitiationofdynamicrecrystallizationweredeterminedfromthe41stress-straincurvesobtained,usingthedoubledifferentiationmethod.Theworkhardeningbehavioruptothecriticalstrainwasanalyzedwiththeaidofadislocationdensitymodelandtheworkhardeningparametersrandhwerederivedinthisway.Theseparameterswereusedtomodeltheausteniteflowcurvesbeyondthecriticalstrain,i.e.intheabsenceofdynamicrecrystallization.Thenetsofteningattributabletodynamicrecrystallizationwasdefinedasthedifferencebetweenthecalculatedworkhardeningcurveandtheexperimentalflowcurve.ThesofteningdataareexpressedintheformofAvramikinetics.UsingthedependencesoftheworkhardeningparametersandAvramikineticparametersonZ,theZener-Hollomonparameter,itisshownhowtheflowcurvespertainingtoindustrialrollingconditionscanbemodeled.
简介:Aphysicalmodelwithmercuryasanalogwasdevelopedtoinvestigatetheinfluencesofelectromagneticstirring(EMS)onflowfieldinslabcontinuouscastingwhenthesubmergedentrynozzle(SEN)wascloggedwithdifferentcloggingrates(0,10%,25%,and50%).TheflowfieldinmoldunderdifferentEMScurrents(0,40A,and60A)wasmeasuredbyanultrasonicDopplervelocimeter.Theresultsprovedthattheflowfieldinthemoldwasatypicaldoublerollstructureundernon-cloggingSEN.AstheSENcloggingrateincreased,theflowfieldstructurewastransformedfromadoublerolltoasymmetryflow.Whenthecloggingratereached50%,theupcirculationdisappearedonthecloggedside.Thezoneunderthemeniscusnearthenarrowfacewasanon-flowingarea.EMScouldcorrectbiasflowcausedbySENcloggingandimprovethesymmetryoftheflowfieldduringSENclogging.
简介:Thecoilingtemperatureofthehotstriprollingprocessplaysanimportantroleinstripqualitycontrol.Thenewly-builtlaminarflowcoolingcontrolsystemwasindependentlydevelopedbyBaosteel.L2conductstotallydynamiccontrol(L1onlyexecutestheresultfromL2,anddoesnotconductanydynamiccontrol).Thesystemhasmanyadvantages,suchasquickreal-timecontrol,accuratemodelcalculation,quickresponseafterself-adaptation,etc.Comparedwiththe2050mmhotstriprollingline,thenewsystemcansatisfythestrictcoolingrequirementsofhighstrengthsteel,siliconsteelandheavyplatesbecauseofitsnewly-developedtechnologiesofcoolingratecontrol,stripcoolingbysectionsandproportion-integral-differentialcoefficient(PID)feedbackfuzzycontrol.
简介:Intwin-rollstripcastingprocess,transportphenomenaoffluidinthemoltenpooldirectlyaffecttheprocessstabilityandthequalityofproducts.Inordertoelucidatethefundamentaltransportphenomenaintwin-rollcasting,acommercialsoftwarecalledProCASTwasemployedtosimulatethetransientfluidflowandlevelprofilebehaviorsduringtheearlystageoftheprocessinthisstudy.Thecoupledsetofgoverningdifferentialequationsformass,momentumandenergybalanceweresolvedwiththefiniteelementmethodandthetransientfreesurfaceproblemwastreatedwithavolumeoffluids(VOF)approach.Theeffectofdifferentdeliverysystemsconfigurationonflowpattern,levelprofileinthepoolwasstudiedandanalyzedinthispaper.Thenewwedgemetaldeliverysystemshavebeenoptimizedforthetwin-rollstripcaster.Itwasshownthatnewtypemetaldeliverysystemshadapreferableeffectontheuniformdistributionoffluidandlevelfluctuationinthepool.Thesimulationresultsalsoprovideavaluablebasisfortheoptimizationofdeliverysystemandprocessparametersduringtheinitialpouringstage.
简介:Bymeansofthenumericalsimulationmethod,themathematicalmodelofinclusionsmovementinthemoldisestablishedundertheconditionofausteniticandferriticstainlesssteelslabproduction.Accordingtothesimulationresults,themainzonesforinclusionparticlesaccumulationwerefoundandmanyfactorsthataffectedfloating-upprobabilityofinclusionparticleswereidentified.Thesefactorsincludetheinclusionparticlesize,thecastingspeedandtheslabwidth,etc.Itisbelievedthattheinclusionparticlesizeisthekeyoneamongthesefactors.
简介:TheeffectofdeformationconditionsondynamicrecrystallizationbehaviorofNb,V,Timicroalloyedhigh-strengthstructuralsteelwasinvestigatedviahigh-temperaturesinglepassreductiontestsonaMMS-300thermomechanicalsimulator,withmathematicalmodelsestablishedforflowstressduringhotdeformation.Theresultsshowthatthedeformationresistancedecreaseswiththeincreaseoftemperatureandisinpowerfunctionrelationshipwiththetemperature.Meanwhile,itincreaseswiththeincreaseofstrainrateandisinlog-logrelationshipwiththestrainrate.Thedynamicrecrystallizationactivationenergyoftestedsteelwasdeterminedtobeabout329.55kJ/mol,295.31kJ/molatpeakandsteadystates.Thepredictionmodelsdevelopedforflowstressindicatedthattheyareingoodagreementwithexperimentalresults.
简介:Inparticulatematerialtransfersystems,traditionalsheartestbasedsteadystateanalysiscanprovidesomeinsightintothestrengthofthebulkmaterialandsubsequentresistivefrictionalforcesduringflow.Forfastflowingtransferpoints,dynamicflowconditionsdominateandadditionalmodellingtechniquesarerequiredtoimprovedesignguidance.Theresearchpresentedshowstheevolutionofadesignsolutionwhichutilisestwodistinctprocesses;acontinuummethodandadiscreteelementmethod(DEM).Initially,theinternalstructureofdensegranularflow,downverticalandinclinedpipeswasinvestigatedusingatwinsensor,12electrodeelectricalcapacitancetomographydevice.Subsequently,DEMsimulationswereconductedusingthecommercialsoftware,PFC3D.Initially,twoparticletypesandtheirflowbehaviourswereanalysed:plasticpelletsandsand.Thepipeanglewasvariedbetween0°and45°tothevertical.Forboththeplasticpelletsandthesand,goodqualitativeagreementwasfoundwiththespatialparticleconcentrationanalysis.Generally,theflowhadadenseparticleregionatitscorewiththeparticleconcentrationreducingawayfromthiscore.Asexpected,at0°,thecorewascentrallylocatedwithinthepipeforboththeplasticpelletsandsand.Atpipeangles5°orgreater,thedensecoreofparticleswaslocatedonornearthepipewall.Averageflowvelocityanalysiswasalsoconductedusingtheresultsofwallfrictiontestanalysis.ThevelocitycomparisonsalsoshowedgoodagreementbetweentheECTimageanalysisandtheDEMsimulations.Subsequently,theDEMmethodwasusedtoanalyseacomplextransfersystem(orchute)withthecontinuummethodprovidingcomparativeflowanalysiswiththeDEMflowanalysis.