多相流基础 chapter 2-two-phase flow patterns and flow pattern maps.ppt

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1、Chaptertwo—Two-phaseflowpatternsandflowpatternmaps（第二章－两相流型和流型图）——gas-liquidtwo-phaseflowhasobviousinterface（气液两相流动具有明显的流动界面）——hasvariousgeometricconfigurations（流动具有各种不同的几何构型）1、Flowpatternorflowregime（流型）Introduction（简介）2、Importantphysicalparametersindeterminingtheflowpa

2、ttern:（流型）——surfacetension（表面张力）KeepchannelswallsalwayswetMakesmallliquiddropsandsmallgasbubblesspherical——gravity（重力）Tendstopulltheliquidtothebottomofthechannelespeciallyinnon-verticalchannel……3、Flowpatternsinverticalupwardtubes——gasandliquidphasebothflowingupwards，adia

3、baticflow（垂直上升管内的流型——气液两相均向上流，绝热流）——Whenthequalityisgraduallyincreasedfrom0to1,theflowpatternscanbeclassified:（1）Bubblyflow（泡状流）LiquidphaseisthecontinuousphaseGasorvaporphaseisthedispersedphaseGasorvaporbubblesareofapproximatelyuniformsize.（2）PlugfloworSlugflow（弹状流）Gasfl

4、owsaslargebullet-shapedbubbles（sometimescalledTaylorbubble）GasbubbleandliquidslugflowacrosstubealternativelySomesmallgasbubblesdistributedthroughouttheliquidphase.（3）Churnflow（搅拌流，块状流）Highlyunstableflow，oscillatoryflowtheshapeofgasbubblesisnotregularLiquidnearthetubewall

5、continuallypulsesupanddown（4）Annularflow（环状流）GasflowsinthecenterofthetubeLiquidpartiallyflowsasanannularfilmonthewallsofthetubeLiquidpartiallyflowsassmalldropletsdistributedinthegasflowinginthecenterofthetube4、Flowpatternsinhorizontaltubes，adiabaticflow（水平管内两相流型，绝热流）——Wh

6、enthequalityisgraduallyincreasedfrom0to1,theflowpatternscanbeclassified:（1）Bubblyflow（泡状流）LowqualityandlowvelocityLiquidisthecontinuousphaseGasorvaporphaseisthedispersedphasenearthetopofthetube（2）Plugflow（塞状流、间歇流）BiggerqualityandlowvelocityIndividualsmallgasbubblescoales

7、cetoproducelongplugsGasbubblesstilltendtoflowalongthetopofthetube（3）Stratifiedflow（光滑分层流）GasandliquidphasehaveobviousinterfaceThegas-liquidinterfaceissmoothThisflowpatterndoesnotusuallyoccurGasandliquidphasearebothcontinuousphaseGasphaseflowsaboveandliquidphaseflowsbelow

8、（4）Wavyflow（波状分层流）GasandliquidphasehaveobviousinterfaceThegas-liquidinterfaceiswavyGasvelocityisbiggert