Title of article :
Structureofair–watertwo-phaseflowinhelicallycoiledtubesOriginalResearchArticle
Author/Authors :
YuichiMurai، نويسنده , , ShinjiYoshikawa، نويسنده , , Shin-ichiToda، نويسنده , , Masa-akiIshikawa، نويسنده , , FujioYamamoto، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2006
Abstract :
Air–watertwo-phaseflowinhelicallycoiledtubesisinvestigatedexperimentallytoelucidatetheeffectsofcentrifugalaccelerationontheflowregimemapandthespatialandthetemporalflowstructuredistribution.Threekindsoftesttubeswith20mminnerdiametersincludingastraighttubeareusedtocomparetheturbulentflowstructure.Superficialvelocitiesupto6m/saretestedsothatthecentrifugalFroudenumbercoversarangefrom0to3.Theinterfacialstructureisphotographedfromtwodirectionsbyahigh-speedvideosystemwithsynchronizedmeasurementoflocalpressurefluctuations.Theresultsrevealthattheflowtransitionlinealtersduetocentrifugalforceactingontheliquidphaseinthetube.Inparticular,thebubblyflowregimeisnarrowedsignificantly.Thepressurefluctuationamplitudegetslargerelativelytotheaveragepressurelossasvoidfractionincreases.Thefrequencyspectraofthepressurefluctuationhavepluralpeaksinthecaseofstrongcurvature,implyingthattheperiodicityofsluggingtwo-phaseflowiscollapsedbyaninternalsecondaryflowactivatedinsidetheliquidphase.Moreover,underlargeFroudenumberconditions,thesubstantialvelocityofthegasphasethatbiasestotheinnersideofthehelicalcoilisslowerthanthetotalsuperficialvelocitybecausetheliquidflowisallowedtopassthroughtheoutersideandsoresemblesaradialstratifiedflow.
Journal title :
Nuclear Engineering and Design Eslah
Journal title :
Nuclear Engineering and Design Eslah
