简介：Abriefreviewwithdiscussionsisconductedforsomepertinentworks,doneandongoingintheLaboratoryofPhase-ChangeandInterfacialPhenomenaatTsinghuaUniversity,oninterfacialbehaviorofvaporbubblesandinterfacialtransportphenomenaduringliquidnucleationboiling.Fromasequenceofexperimentalinvestigations,somenewphenomena,particularly,thevisuallyobservedinterfacialtransportphenomenaorprocessesincludingjet-likeflows,bubbleinteractionandspatialscaleeffect,weredescribedinthisarticle.Theinterfacialeffectsandtransportphenomenaassociatedwithsurfacetensiongradientscausedbytemperatureandconcentrationvariationsweretheoreticallyanalyzedtorevealthemarkedinfluenceonbubbleinterfacialshapeanddynamicbehavior,thebubbledynamicsincludingnucleation,bubblemotionandcoalescence.Severaltheoreticalmodelsandmethodswereproposedtodescribethedynamiccharacteristicsandexplainthephysicsofinterfacialphenomena/processes.Thespe

简介：ThispaperdealswithanexperimentalinvestigationofpinfinboilingofsaturatedandsubcooledHFE-7100underatmosphericpressure.Finbasetemperatureandheatfluxdataaremeasuredalongwiththefintiptemperature.ThebasicfeaturesofboilingstabilityofHFE-7100boilingonpinfinhadbeenreportedforthefirsttime.Foragivenliquid/heatingsurfacecombinationthereexistuppersteady-state(USS)branchandlowersteady-state(LSS)branch,andalarge,unstableregimelocatedinbetween.Zoneswithdifferentstabilitycharacteristicsaremappedaccordingtoboilingonfinswithdifferentaspectratios.Liquidsubcoolingcanlargelyenhanceheattransferperformance.Alongerfincanprovideasaferoperation.

简介：AdetailedstudyofthepressureoscillationinducedbythefilmboilingofHeⅡispresented.Thefilmboilingstateandthestabilitynofthevapourfilmaredeterminedbythegoverningparameter(i.e.theimmersiondepth).Itisfoundthatthepowerdensityspectrumofthepressureoscillationinducedbythefilmboilingdisplaysthe1/f^α-behaviour.Theexponentαwasfoundtobewithintherangefromonetotwo,whichindicatestheexistenceofself-organizedcriticalityinthefilmboilingofHeⅡ.

简介：Amechanismisproposedfornucleatepoolboilingheattransferalongwithageneralmodelforbothpureliquidsandbinarymixtrues.Acombinedphysicalmodelofbubblegrowthisalsoproposedalongwithacorrespondingbubblegrowthmodelforpureliquidsonsmoothtubes.Usingthegeneralmodelandthebubblegrowthmodelforpureliquids,ananalyticaslmodelfornucleatepoolboilingheattransferofpureliquidsonsmoothtubesisdeveloped.

简介：ＶＡＰＯＲＩＺＡＴＩＯＮ　ＨＥＡＴ　ＡＴ　ＮＯＲＭＡＬ　ＢＯＩＬＩＮＧ　ＰＯＩＮＴ　ＡＮＤ　ＭＯＬＥＣＵＬＡＲ　ＴＯＰＯＬＯＧＹ　ＦＯＲ　ＰＡＲＡＦＦＩＮＳＶＡＰＯＲＩＺＡＴＩＯＮＨＥＡＴＡＴＮＯＲＭＡＬＢＯＩＬＩＮＧＰＯＩＮＴＡＮＤＭＯＬＥＣＵＬＡ...

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简介：HeattransfercoefficientsinnucleateboilingonasmoothflatsurfaceweremeasuredforpurefluidsofR-134a,propane,isobutaneandtheirbinarymixturesatdifferentpressurefrom0.1to0.6MPa.Seriesofexperimentswithdifferentheatfluxandmixtureconcentrationswerecarriedout.Theinfluencesofpressureandheatfluxontheheattransfercoefficientfordifferentpurefluidswerestudied.Isobutaneandpropanewereusedtomakeupbinarymixtures.Comparedtothepurecomponents,binarymixturesshowlowerheattransfercoefficients.Thisreductionwasmorepronouncedastheheatfluxincreasing.Severalheattransfercorrelationsareobtainedfordifferentpurerefrigerantsandtheirbinarymixtures.

简介：Boilingheattransferprocessisanalyzedinamoderatenarrowspaceconsistedoftwohorizontalplates,Themaindifferencebetweenthisprocessandtheconventionalunconfinedpoolboilingistheliquidsupplymechanismwhichisabsolutelypreventedbythegrowthofcoalescencebubblealongwiththeheatedsurfaceinthenarrowspace.Asaresult,themacrolayerbecomesthinnerduetotheevaporationoftheindividualbubbleswithinthemacrolayerduringtheperiodofbubblecoalescence,withorwithoutdryoutthatdependsonboththegapsizeofnarrowspaceandthesizeofheatedsurface.Foraspecifiedsizeoftheheatedsurface,theinitialthicknessoftheliquidlayerhasacriticalvaluewhichapproachesaconstantwhilethespaceheightislargerthanacriticalvalue.Theindividualbubblebehaviorsandtheheattransfercanbeconsideredasthesameasthatintheunconfinedpoolboiling,ifthespacegapislarge,However,theindividualbubblesdonotgenerateinthelastperiodofthebubblecoalescenceandalowermaximumheatfluxwillberesultedifthespacegapisreduced.Insuchacase,themacrolayerisdryout.

简介：InrecentlypublishedpaperbyYangChunxin[1],Ireexaminedthepaper.Onpage128,thepaper'pointedoutthatthesizeandspatialdistributiondensityofnucleationsitespresentedonrealboilingsurfacecanbedescribedbythenormalizedfractaldistributionfunction,andthephysicalmeaningofparametersinvolvedinsomeexperimentalcorrelationsproposedbyearlyinvestigationsareidentifiedaccordingtofractaldistribution'.However,thedefinitiononfractaldimensiongivenbyYang[1]ishighlyquestionable,andtheresultsobtainedbyYangarecontradictorytothebasicfractaltheory.Herearemycomments:

简介：在使过冷的流动与水力的直径Dh=1mm在单个水平矩形的microchannel沸腾的限制水泡和伸长的水泡的特征试验性地被学习。有1的隧道

简介：Acombinedphysicalmodelofbubbelgrowthispropsedalongwithacorrespondingbubblegrowthmodelforbinarymixturesonsmoothtubes.UsingthegeneralmodelofWangetal.^[1].andthebubblegrowthmodelforbinarymixtures,ananalyticalmodelfornucleatepoolboilingheattransferofbinarymixturesonsmoothtubesisdeveloped.Inaddition,nucleatepoolboilingheattransferofpureliquidsandbinarymixtruesonahorizontalsmoothtubewasstudiedexperimentally.Thepureliquidsandbinarymixturesincludedwatermethanol,ehanol,andtheirbinarymixtures.Theanalyticalmodelsforbothpureliquidsandbinarymixturesareingoodagreementwiththeexperimentaldata.

简介：ＴＨＥＬＩＮＥＡＲＳＥＰＡＲＡＴＥＤＦＬＯＷＭＯＤＥＬＦＯＲＴＷＯ－ＰＨＡＳＩＦＬＯＷＩＮＳＴＡＢＩＬＩＴＹＩＮＢＯＩＬＩＮＧＣＨＡＮＮＥＬＳ￥ＺｈｏｕＹｕｎ－ｌｏｎｇ；ＳｈｅｎＺｅｎｇ－ｍｉｎｇ；ＳｈｉＨｕｉ－ｘｉａｎ（ＮｏｒｔｈｅａｓｔＣｈｉｎａ...

简介：现在的学习报导R134a流动在微隧道的热水池沸腾特征的热转移的试验性的评估。热水池由30平行组成矩形与500m宽度和深度的代表性的尺寸微隧道，以及全部长度30mm。实验与热流动被进行直到从373.33～1244.44kg/m22,团速度>s，蒸汽质量从0.06～0.9。加热的热水池的墙温度能在约50点被控制

简介：水泡的行为上的可视化研究为水池在压力0.1MPa在一个水平透明加热器上沸腾R141b被执行了。水泡的行为被在加热器表面下面放的一个高速度的照相机记录。离开直径，水泡的离开时间和在不同的热流动的成核地点密度被获得。可视化结果证明水泡离开直径和离开时间减少，当当热流动增加，成核地点密度增加时。没有液体，在实验招募进microlayer，这也被观察。基于试验性的结果，煮曲线因为R141b被使用动态microlayer模型预言。作为结果，在基于动态microlayer，为沸腾的模型和实验数据R141b弄弯的预兆的结果之间的协议擅长高热流动。关键词R141b-热转移-水泡动力学-水池沸腾CLC数字TK124

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简介：Ethanol-waterbinarymixtureswith7differentmolefractionsofethanolrangingfrom0to1wereadoptedastestingliquidsintheexperiment.Theverticalheatingtubewasinsertedinporousmatrixcomposedoffivewellsortedglassbeadswhisediametersrangefrom0.5to4.3mm.Duetotheeffectofcomposition,thetrendofcombinationofvaporbubbleswasreduced.resultingintheincreaseofpeakheatfluxofbinarymixture,Withtheincreaseofethanolmolefraction,0.5mmdiameterbeadofpeakheatfluxofbinarymixture.withtheincreaseofethanolmolefraction.0.5mmdiameterbeadhadlowervalueofpeakheatflux,whileforpureliquidthecriticalstateisdifficulttoappear,withgivendiameterofglassbead,thereexistedanoptimumvalueofmolefractionofethanol,whichwasdecreasedwiththeincreaseofbeaddiameter,Adimensionlessheattransfercoefficientwaspredictedthroughtheintroductionofadimensionlessparameterofporousmatrixwhichagreedwiththeexperimentalresultssatisfactorily.

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简介：Toinvestigatethesizeeffectonthecharacteristicsofboilingheattransfer,boilingbehaviorofFC-72inheatedverticalminiaturecirculartubesimmersedinaliquidpoolwasexperimentallystudied.TwoAISI304stainlesssteeltubeswithinnerdiametersof1.10mmand1.55mmcorrespondingly,wereheatedbyswirledNi-CrwireheatersandsealedinLuciteblocksbysiliconadhesive.Boththetopandthebottomendsofthecirculartestsectionswereopentotheliquidpool.Theboilingcurvesandheattransfercoefficientswereobtainedexperimentally.Theboilingbehaviorsattheoutletsoftheminiaturetubeswerealsovisualizedwithadigitalvideocamera.Experimentalresultsshowthatthetubegeometryhasasignificanteffectontheboilingcharacteristics.Vaporblockingattheoutletofthesmallercirculartubewithadiameterof1.10mmcausedsevereboilinghysteresisphenomena.TheCHFdecreasedwithreducingintubesize.

简介：Theboilingbehavioroftheliquidnitrogen(LN2)underthetransienthighheatfluxurgentlyneedstoberesearchedsystematically.Inthispaper,thehighpowershortpulsedurationlaserwasusedtoheatthesaturatedLN2rapidly,andthehigh-speedphotographyaidedbythesparklightsystemwasemployedtotakeseriesofphotoswhichdisplayedtheprocessofLN2'sboilingbehaviorundersuchconditions.Also,aspecialtemperaturemeasuringsystemwasappliedtorecordthetemperaturevariationoftheheatingsurface.TheexperimentsindicatedthatanexplosiveboilinghappenedwithinLN2bythelaserheating,andaconventionalboilingfollowedupafterthenewly-definedchangeovertime.Byanalyzingthetemperaturevariationoftheheatingsurface,itisfoundthatthelatentheatreleasedbythecrackofthebubblesinthebubbleclusterinducedbytheexplosiveboilingisanimportantfactorthatgreatlyinfluencestheboilingheattransfermechanism.

简介：ThemoleculartransformationsofcarboxylicacidsinheavyacidicSLcrudebeforeandaftertrueboilingpointdistillationwereexaminedbyultra-highresolutionnegative-ionelectrosprayionization(ESI)Fouriertransformioncyclotronresonancemassspectrometry(FT-ICRMS).Theacidclass(heteroatomnumber),type(znumbers)andcarbonnumberdistributionswerepositivelycharacterized.Itwasfoundoutthatthetotalacidnumber(TAN)ofSLcrudedecreasedaftertrueboilingpointdistillation,andtheabundanceofO2classinmassspectrawasalsofoundtobereducedfrom67.6%to34.5%inSLTBPmixedcrudeasmeasuredbyMSspectra,indicatingtoapotentialcarboxylicaciddecomposition.However,itwasinterestingthatthecarboxylicacidstypedistributioninbothoilswasalmostthesamealthoughtheirrelativeabundanceinSLTBPmixedcrudeturnedtobemuchlower,suggestingthatvariouspetroleumcarboxylicacidtypeshavethesimilarthermaldecompositionreactionbehavior.Furthermore,foreachO2typeofacidsinSLTBPmixedcrude,theabundanceofcarboxylicacidswithcarbonnumberhigherthan35wasreducedgreatly,especiallyforthosewithcarbonnumberhigherthan60,themasspeaksofwhichwerenearlytotallyremoved,indicatingthatthelargecarboxylicacidmoleculesinheavyfractionsdecomposedmoresignificantlybecauseoflongerheatingtimeduringthetrueboilingpointdistillationprocess.Asaresult,thereductionofTANmaybecausedbythethermaldecompositionofcarboxylicacidsespeciallythosewithhighcarbonnumber,suggestingthatquickdistillationormuchlowerpressureisrequiredtoavoidthethermaldecomposition.