r290与r404a内螺纹管中沸腾换热研究

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1、题安建筑科技大学硕士论文IvestigationOnFlowBoilingHeatTransferCharacteristicsofR290andR404AinHorizontalMicrofinTubeSpecially：Heating,VentilationandairconditioningName：HanXiaoxiaSupervisor：．NanXiaohongABSlRAC．rInrecantyears，duetOthephase-outofHCFCsinrefrigerationandairconditioningindustry,refi'igerants

2、whichdolittleharmtOenvimmentaIebeingdevelorxxlandtheirthermodynamiccharacterizesare城ngstudieddeeply．BecameresearchonsubstitutionsforR22showsthattheheattrans蠡ei"abilitiesof溉substitutionsarelessthanthatofR22．microfintubesaleappfiedt0augmentin-tubeevaporationmadcondensationheattransfer．Theob

3、jectiveofthisd瓷髹畦倒jonistOconductOiltheoficalanalysisandcalculationuponflowboilingheattransferinsidehorizontalsmoothandmicrofmtubeofR290andR404A,whicharenewlyenvironmentalreplacementsofR22．Andthemajorpartsofthedissertationareasfollows：1．Somedifferenternr晒耐formulations013prcdicfingthein-tub

4、eboilingheattransfercoefficients勰examined．2．Basedontheexpe妇协王datacohered,theformulationswhichcarl珊。did∞．,caratelyin-tubeboilingheatWansfercoefficientsofR290andR404Aareseleted．Shahcorrelationcan辫,edictpreciselyheatwansfercoefficientsofR290andR404Ainhorizontalsmoothtube．Koyamacorrelationwhi

5、chismodifiedcanpredictpreciselyheattrflllsfercoefficientsofR290insidehorizontalmicmfintube．Thomecorrelationhasgood弘edsonincalculatingheatwansfercoefficientsofR404Ainsidehorizontalmicrofintube．3．Theanalysesondifferentempiricalformulationsofin-tubeboilingheattransfercoeffidcntsindicatethatR

6、404Acanbetreatedaspttrerefrigerantduringcalculatingitsthein-tubeboilingheattransfercoefficieaats．4．TheeffectsofgeometricalparametersofmicmfintubesOnthein-tubeboilingheattransfercoefficientsisanalyzed．Inaddition,theprinciplesonintensifyingheattransferinmicrofintubeisalsoanalyzed．5．Lockhart

7、&Martinellipressuredropcomelationisstudied，andatthesametime，basedonthe西安建筑科技大学硕士论文IIIIIexperimentaldatacollected，theaccuracyofthisformulationisexamined．6。霹嚣evaluatingmethodonintensifyingheattransferperformanceinmicmfintubeispmvidext,andbythismethodtheperformanceofR2