Abstract:Thetwo-phaseflowinanaxialgas-liquidseparatoriscriticalforthegasseparationinthethoriummoltensaltreactor.Althoughthetwo-phaseflowpatternisvisualizedandthevelocityfieldisobtainedinourpreviousstudies,theturbulencefieldisstillunknown.Toclarifythestatisticsoftheturbulencefield,weusedthestereoPIVtechniquetoexploretheinstantaneousfluctuationsofthreevelocitycomponents.TheturbulenceinformationincludingtheturbulentkineticenergyandthreetypicalReynoldsshearstresseswereextractedfromfivetypicalplanarpositionscoveringthewholeswirlchamber.Theresultsindicatethatthedistributionofturbulencestatisticspresentsaverydifferenttendencyofdistribution,ascomparedtoconventionalcyclones.Thedifferenceisdistinguishedbythevaryinganisotropicstressfieldandthedoublepeakdistributionofturbulentkineticenergy.Theturbulencedataprovidesacompleteandreliablefoundationfortwo-phaseturbulencemodeling.Keywords:PIV;swirlflow;Turbulencestatistics
1Introduction
Inthedevelopmentoffissiongasremovalsystemformoltensaltreactors,anaxialgas-liquidseparatorwasproposedbytheOakRidgeNationalLab(ORNL)[1,2].AsshowninFig.1(a),theseparatorconsistsofswirlvane,swirlchamber,recoveryvane.Fig.1(b)isthesketchofgas-liquidflowintheswirlchamberwherebubblesdispersedintheliquidphasefromtherighthandsidewillbedrivenintotheaircoreduetothelargeradialpressuregradientintheswirlchamber.Thegas-liquidmixturewithahighcontentofgaswillbeseparatedviaupstreamanddownstreamorificeslinkedbytwobranchpipes(BP1andBP2).Pureliquidisobtainedinthelefthandsideandgas-liquidmixtureisstrippedoutviathedownstreamorificeandtheupstreamorifice.Theflowpatternisfeaturedbyaprominentswirlflowembeddedwithanaircore[3](seeFig.1(c)).Inviewofseparatordesign,howthebubblesinteractwiththeswirlflowandhowtheaircoreevolvesdependsonanin-depthunderstandingoftheturbulentflowfieldoftheliquidphase[4].