外文翻译旋风分离器对称蜗管进口的实验室研发

ShortcommunicationDevelopmentofasymmetricalspiralinlettoimprovecycloneseparatorperformanceBingtaoZhao*,HenggenShen,YanmingKangDepartmentofEnvironmentalEngineering,DonghuaUniversity,No.1882,YananRd.,Shanghai,Shanghai200051,ChinaReceived28October2003;receivedinrevisedform24February2004;accepted3June2004Availableonline17July2004AbstractThreecycloneseparatorswithdifferentinletgeometryweredesigned,whichincludeaconventionaltangentialsingleinlet(CTSI),adirectsymmetricalspiralinlet(DSSI),andaconvergingsymmetricalspiralinlet(CSSI).Theeffectsofinlettypeoncycloneperformancecharacteristics,includingthecollectionefficiencyandpressuredrop,wereinvestigatedandcomparedasafunctionofparticlesizeandflowrateinthispaper.Experimentalresultindicatedthatthesymmetricalspiralinlet(SSI),especiallyCSSIinletgeometry,haseffectonsignificantlyincreasingcollectionefficiencywithinsignificantlyincreasingpressuredrop.Inaddition,theresultsofcollectionefficiencyandpressuredropcomparisonbetweentheexperimentaldataandthetheoreticalmodelwerealsoinvolved.Keywords:Cyclone;Symmetricalspiralinlet;Collectionefficiency;Pressuredrop1.IntroductionCycloneseparatorsarewidelyusedinthefieldofairpollutioncontrolandgas–solidseparationforaerosolsamplingandindustrialapplications[1].Duetorelativesimplicitytofabricate,lowcosttooperate,andwelladapt-abilitytoextremelyharshconditions,cycloneseparatorshavebecameoneofmostimportantparticleremovaldevicethatpreferablyisutilizedinbothengineeringandprocessoperation.However,theincreasingemphasisonenviron-mentprotectionandgas–solidseparationisindicatingthatfinerandfinerparticlesmustberemoved.Tomeetthischallenge,theimprovementofcyclonegeometryandper-formanceisrequiredratherthanhavingtoresorttoalterna-tiveunits.Manyresearchershavecontributedtolargevolumeofworkonimprovingthecycloneperformance,byintroducingnewinletdesignandoperationvariables.TheseincludestudiesoftestingacyclonicfractionatorforsamplingthatusedmultipleinletvanesbyWeddingetal.[2],developingamathematicmodeltopredictthecollectionefficiencyofsmallcylindricalmultiportcyclonebyDeOtte[3],testingamultipleinletcyclonesbasedonLapple’typegeometrybyMooreandMcfarland[4],designingandtestingarespirablemultiinletcyclonesamplerthatminimizetheorientationbiasbyGautamandStreenath[5],andcomparingtheperformanceofadoubleinletcyclonewithcleanairbyLimetal.[6].Inthispaper,thenewinlettype,whichisdifferenttypeofinletfromthatusedbyformerresearchers,wasdeveloped,andtheexperimentalstudyonaddressingtheeffectofinlettypeoncycloneperformanceswaspresented.2.ExperimentalThreekindsofcycloneseparatorswithvariousinletgeometries,includingconventionaltangentialsingleinlet(CTSI),directsymmetricalspiralinlet(DSSI),andconverg-ingsymmetricalspiralinlet(CSSI),weremanufacturedandstudied.ThegeometriesanddimensionsthesecyclonesarepresentedinFig.1andTable1.Toexaminetheeffectsofinlettype,allotherdimensionsweredesignedtoremainthesamebutonlytheinletgeometry.*Correspondingauthor.Tel.:[phone];fax:[phone].E-mailaddress:[e-mail](B.Zhao).PowderTechnology145(2004)47–50TheexperimentalsystemsetupisshowninFig.2.Thepressuredropsweremeasuredbetweentwopressuretapsonthecycloneinletandoutlettubebyuseofadigitalmicromanometer(SINAP,DP1000-IIIC).Thecollectionefficiencywascalculatedbytheparticlesizedistribution,byuseofmicroparticlesizeanalyzer(SPSI,LKY-2).DuetohavingthesamesymmetricalinletinModelBorC,theflowrateofeachinletofmultiplecyclonewasequaltoanotherandcontrolledbyvalve;twonozzle-typescrewfeederswereusedinsameoperatingconditionstodispersetheparticleswithaconcentrationof5.0g/m3ininlettube.Thesolidparticlesusedweretalcumpowderobeyedbylog-normalsizedistributionwithskeletaldensityof2700kg/m3,mass–meandiameterof5.97Am,andgeometricdeviationof2.08.Themeanatmosphericpressure,ambienttemperature,andrelativehumidityduringthetestswere99.93kPa,293K,andlessthan75%,respectively.3.Resultsanddiscussion3.1.CollectionefficiencyFig.3showsthemeasuredoverallefficienciesofthecyclonesasafunctionofflowratesorinletvelocities.Itisusuallyexpectedthatcollectionefficiencyincreasewiththeentrancevelocity.However,theoverallefficiencyofthecyclonewithsymmetricalspiralinletbothModelsBandCwasalwayshigherthantheefficiencyofthecyclonewithconventionalsingleinletModelAatthesamevelocity;andespecially,thecyclonewithCSSI,ModelChasahighestoverallefficiency.Theseeffectsofimprovedinletgeometrycontributetotheincreaseinoverallefficiencyofthecycloneby0.15–1.15%and0.40–2.40%inthetestedvelocityrange.Fig.4(a)–(d)comparesthegradecollectionefficiencyofthecycloneswithvariousinlettypesattheflowrateof388.34,519.80,653.67,and772.62m3/h,withtheinletvelocitiesof11.99,16.04,20.18,and23.85m/s,respectively.Asexpected,thefrictionalefficienciesofallthecyclonesareseentoincreasewithincreaseinparticlesize.Theshapesofthegradecollectionefficiencycurvesofallmodelshaveaso-called‘‘S’’shape.ThefrictionefficienciesoftheDSSI(ModelB)andCSSIcyclones(ModelC)aregreaterby2–10%and5–20%thanthatfortheCTSIcyclone(ModelA),respectively.Thisindicatesthattheinlettypeorgeometrytothecyclo