A new device for assessing film stability in foams_ Experiment and theory

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1、ColloidsandSurfacesA:Physicochem.Eng.Aspects382(2011)64–73ContentslistsavailableatScienceDirectColloidsandSurfacesA:PhysicochemicalandEngineeringAspectsjournalhomepage:www.elsevier.com/locate/colsurfaAnewdeviceforassessingfilmstabilityinfoams:ExperimentandtheoryM.Kostog

2、lou,E.Georgiou,T.D.Karapantsios∗DepartmentofChemicalTechnology,SchoolofChemistry,AristotleUniversity,Univ.Box116,54124Thessaloniki,GreecearticleinfoabstractArticlehistory:AnewdeviceisproposedforregisteringthinfilmdrainagearoundasinglefoambubblebasedontheReceived27Septem

3、ber2010increaseoftheelectricalresistanceofthedrainingfilm.Initially,asmallbubbleisexpandedinsideanelec-Receivedinrevisedformtricallyconductiveliquidbridgethatisformedbetweentwoverticallyalignedmetallicelectrodes.Then13December2010theliquidofthebridgeiswithdrawnatapre-se

4、lectedflowrateuntilruptureofthebridge/bubblesystemAccepted16December2010whilemonitoringitselectricalresistanceacrosstheelectrodes.Thepresentworkreportsresultsforliq-Availableonline23December2010uidwithdrawalratesbetween20and200l/hwhichcorrespondtototaldrainagetimebetwe

5、en∼3and∼25min.ExperimentsareperformedwithaqueoussolutionsofSDSbetween50and2000ppm.AsimpleKeywords:theoreticalmodelisusedtodescribetheevolutionoftheresistanceofthegloballiquidbridge/bubbleFoamstabilityCoalescencesystem.Themodelassumesaperfectlysphericalbubblewhichaffect

6、stheshapeoftheliquidbridgeonlySurfactantstabilizationasavolumeconstraint.AsimpleapproachisemployedforthecomputationoftheelectricalresistanceLiquidbridgeofthesystemduringthelaststagesofdrainagewherethethinfilmaroundthebubblegetsgraduallyThinfilmthinnerandstretchesuntilrup

7、ture.Adetailedparametricstudyofthemodelispresented.Thecom-Electricalresistancemeasurementsparisonbetweenexperimentalandmodelresultsdemonstratesthepotentialofthenewdevicefortheassessmentoffoamstabilitywithrespecttocoalescence.©2010ElsevierB.V.Allrightsreserved.1.Introdu

8、ctionThebubblesizedistributionevolvestowardslargersizesandthemechanismforthisdependsonthestabilityoftheinterbubbleFoa