喷射器内气液流动与混合性能的.研究

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1、青岛科技大学研究生学位论文(2)TheReynoldsnumberatnozzleRes，gasReynoldsnumberattheinletofmixingtubeReGandgastoliquidflowrateratioG／Lhaveeffectsontheflowpatterns．IfRes=2．36x1041．27x10’．whenG／L．S0．2thebubbleflowexists．WhenG／L>0．2，thejetflowdoes．IftheflowpaRemisthejetflow,theli

2、quidjetlengthdependsontheRes，ReGandG／L：whentheResconstant．theliquidjetlengthincreasestothemaximumatfirstandthendecreasesandatlaststabilizesatsomevalue．ThemaximumliquidjetlengthsatdifferentReNaredifferentwhichincreasesatfirstandthendecreaseswiththeResincreasing

3、．WhenReN=5．84×104，themaximumliquidjetlengthisthemaximum．Inaddition．thefinalstablelengthatdifferentReNisalsodifferentanditdecreaseswiththeReNincreasing．Afterthedisintegrateoftheliquidjet，thegas-liquidflowformsthreepatternsofbubbleflow,cloudyflowandblockflow．Whe

4、nReG<5．0×10z，theflowisbubbleflowinthediffuseroftheejector．WhenReG>4．5x103，theflowisblockflowinthediffuseroftheejector．WrllenReG=5．OxlOz~4．5×103时，theflowalongtheaxialdirectionisjetflow,cloudyflowandbubbleflow．Intheejectorseveralflowpatternscancoexistandalsojust

5、occuronepaaemsuchasbubblefloworjetflow．(3)Whenthebubbleflowispresentintheejector,themixingeffectofgasandliquidisbest．ThebubbleflowvelocityandsizedistributionwerediscussedbytheuseofPIVmeasurementandCFDsimulation．Intheabsenceofswirlthedirectionsoftheaveragebubbl

6、evelocityrotatesabitbutthemajorityparalleltotheaxiallineorthewall．‰ntheswirlpresents．theaverageflowfieldshowsthatthedegreeofupwardmotionoftherotationincreases．(4)ThenozzleReynoldsnumber，thegasReynoldsnumber(mixingtubeinlet，noswirl)andthemixtureReynoldsnumber(w

7、henthereisswirl)，andG／Laffectsthespecificdistributionofbubblesinbubbleflow．Whenthereisnoswirlintheejector,thegastendstodisperseintouniformbubblesintheliquid．AtthesameRes，thebubblesizeincreaseswithReGincreasing．AtthesameReo，thelargerthenozzleReynoldsnumber,thes

8、mallertllebubblesize．Inthepresenceofswirl，thebubbledistributionsaredifferentfromthoseintheabsenceofswirl．Thebubblesareinclinedtogatheraroundtheaxiallineasymmetricallyandform“bubble