文献翻译-机械搅拌槽挡板的研究

英文翻译MechanicalstirringchestbackplateresearchMechanicalstirringchestreasonablestructureincludingmixerchoice,stirringcheststructureaswellasbackplatestructuralstyle.Anyplacementthestaticpartallconstitutesthebackplatebesideinthestirringdevicetrough.Thusthebackplatemaydivideintotwokinds:ThemostcommonbackplateformisverticalinstallsYuCaobithecomponent,namelywallbackplate;Anotherkindisthespecialbackplate,theshape,thepositionrespectivelydifferent,isconfidentthebackplate,thesuperficialbackplateandsoon,intherecuperatortubeandtheinsertiontroughundertheliquidlevelvaporpipe,theairconduitandtheinletpipeandsooninternalcomponentalsocanplaythebackplaterole.First,thebackplatefunctionbackplatebasicfunction,ischangestheliquidrotarymotiontheverticaltiltingmotion,eliminatesthewhirlpool,simultaneouslyimprovesexertsthepowertheeffectiveusefactor.Thebackplatehaslimitedtheliquidtangentialspeed,increasedaxialandtheradialvelocitycomponent,itspurificationisenablethemixerexhauststreamtohaveawidermobileradius,theexhauststreamwhichmixerrevolvingproduces,becauseofthetroughwallandthebackplatefunction,formsinthestirringchestthecomplexflowfield,theflowpattern,thespeedsizeandthedirectionandsoonhasbecauseofthemixerimpellerandthebackplatemutualfunctionthechange,themixeffectobtainstheremarkableenhancement.Second,theentirebackplateconditionpoweristhemixercharacteristicparameter.Regardingspecificmixer(impellerformandrotationalspeedinvariable),thepowerincreasesalongwiththebackplatecoefficientincreases.Butwhenthebackplatecoefficientachievedwhencertainvalue,thepowercannotfurtherincrease,butisthebasicmaintenanceisconstant.Thistimethrustplatecoefficientiscalledtheentirebackplatecondition,namelytheagitationpowerachievessaturated.Inthestirringchestactualdesign,accordingtothebackplatewidth,quantityempiricalstipulatedthat,usuallyusesverticalYuCaobi4widthbdistheD/12D/10backplate(calledgenerallyit“standardbackplate”)satisfiestheentirebackplatecondition,thisisbecauseofthebasisformula(1),undertheentirebackplateconditionbackplatesize,quantityandtheshapearebynomeansmostsuperior.Thesuitablebackplateconditionprovidestheflowpatterncandrivetheentiretroughthematerialmovement,guaranteestheintensivemixing;Butexcessivelymanybackplates,namelythestirringchestthebackplate,hasreducedtheoveralltobemobile,andwillmixthelimitationinthepartialregion,willcausenotthegoodmixperformance.Third,thebackplatetothepowertheinfluenceinthenon-backplatestirringchest,anytypemixer,willallproducethetangentialflowandtheswirl.Afterestablishesthebackplateabout,thetangentialflowcomesunderthesuppressionorthehindrance,inthetroughhasthelargescalemovementwhichchanges,thewhirlpoolelimination.Thestandardbackplatecontainsthedualmeanings:Powersaturatedandwhirlpoolelimination.Butthestandardbackplateoptimizesthestructurebynomeans.1st,agitationpowercomputationinhydrometallurgyprocess,mixerimpellerusuallyforpropellortype,pushertypeandturbinewheeltype2nd,thebackplatestructuretothepoweraccuratenumberinfluence(1)theoreticalanalysisbasismixerpowerhydromechanicsfoundationanalysis,thepoweraccuratenumberphysicssignificanceisthefrictioncoefficient.Speakingofthemixerimpeller,underthefullturbulentconditions,theformresistanceistheresistanceimportantconstitution,thusthepoweraccuratenumberisdecidedbythestirringchestgeometrystructure.Thebackplategivesthedifferentimpellerbythedifferentinfluence(2)experimentanalyzedthebackplatetoincreasethemixerpowerconsumption,simultaneouslyimprovedthemixeffect.Regardingthedifferentformpaddleblade,thebackplateinfluenceisdifferent.Underthesamemediumcondition,theusedifferentformpaddleblade,inhasin4kindofbackplatestructuresmallstirringchesttocarryontheexperiment(inexperimentnd=4),obtainsagroupofpoweraccuratenumber,seeTable1.DatamayobtainthefollowingstructurebyTable1:Thebackplatecoefficientpairprocessradialflowpaddleblade(discturbinewheeloar)affectsinabigway,tosimultaneouslyproducestheradialflowandtheaxialflowpaddleblade(flapturbinewheeloar)isnext,thepairprocessaxialflowpaddleblade(propeller)affectsslightly;Regardingidenticaltypepaddleblade,backplatecoefficientenlargement,alsocausesthepoweraccuratenumbertheincrease;Whenimpellerformandbackplatecoefficientsame,thebackplatestructureimprovement,maychangethepoweraccuratenumbersimilarly,andinsatisfiesthepowerinputundertheconditiontoimprovethemediumthemixperformance.Inaddition,furtherobservestheexperimentalphenomenonalsotobepossibletodiscoverthat,thechart1anarrowbackplatestructure,themediumcenterhasproducedtheobviouswhirlpoolandthevolumeintheexperimentattracts,hasshownthesmallbackplatealthoughthepowerdissipationissmall,hasnotachievedtheeliminationwhirlpoolactuallythegoal,butFigure1b,c,dbackplatestructurenotthisphenomenonoccurrence.Butatthebackofthechart1dstandardbackplateappearedthemediumminorcycle,andasaresultofthebackplatehindrance,inthisminorcyclemediumisunabletobeseparatedfromtherenewal,thereforeformstheendlessloop.Explainedthiskindofstructurecausedthepartialmixnottobefull;Butchart1b,atthebackofcbackplatealthoughalsohastheminorcycle,butbecausethebackplateleavesleewaythecrevice,causesintheminorcyclethemediumtocarryoffunceasinglybyotherdirectionliquidflow,thenewmediummaysupplementunceasingly,itsmixeffectisextremelyideal.Fourth,thepracticalapplicationbackplatestructureoftenreceivesthestirringchesttroughbodymaterialthelimit.Thehydrometallurgyusestheagitationequipmentinternalmaterialusuallyforthefinemetal,themetaloutercoveringinsideliningrubber,themetaloutercoveringinsideliningrubberandtheanti-corrosivebrick,thecoagulationoutercoveringinsideliningglassfiberreinforcedplasticortherubberandtheanti-corrosivebrickandsoon.Regardingthefinemetalorthemetaloutercoveringinsideliningrubberstirringchest,theearlytimeuseschart1dmuchthebackplatestructure,recentlyforcoordinatesthemixerimpellerpattern,chart1b,thecbackplatestructurebecomesthemainstream.Inaddition,alsohasconceivedinthefinemetaltroughinvivoestablishmentmeshbackplateorthegrillbackplate,ontheonehandsavesthematerial,ontheotherhandcoordinatestheimpellertochangethemediumflowpattern,enhancestheagitationeffect.Buttheseallwaitforunceasinglytheexperimentalstudy.Speakingofthemetalortheconcreteoutercoveringinsidelininganti-corrosivebrickstirringchest,becausethebackplatebrickmustinsertinturnthetroughnogging,causesittobecomeawholewiththetroughwall,avoidsstirringintheprocessbrickabscission,thereforeandhollowsoutthestructuretothewallnotsuitablytousegenerally,mostlycontinuestousechart2thebackplatestructure,variousrefineriespresentlyuseoverwhelmingmajorityliningbrickstirringchestforthiskindofstructure.ButtheZhuzhouRefineryliningbrickleachingvatandthepurificationtroughareexceptions,becausesomeoverseasstirringdevicesupplierproposed,itprovidesthemixermustunderthespecificbackplatestructurebeabletoachievetheanticipatedagitationeffect,namelythebackplatemustleavethebottomaccordingtothebasicsizetothewall,thereforewetodesignedhavemadethechangewhichasshowninFigure2.Althoughthischangehassatisfiedtheagitationrequest,butinvestedmanyincreases(eachstirringcheststainlesssteelamountofusetoincreasenear2t).Howthereforecausesthemixerandthebackplatestructureintheliningbrickstirringchestachievedamoreperfectconjunction,isworthfurtherstudying.Therefore,regardingtheagitationmixperformanceoptimizedrequest,causesthebackplatetoreceivetheattentioninagitationflowfieldfunction,andenablethebackplateformtotendtothediversification.Inparticularthemulti-impellers,thepoly-phasesystem,disperse,thesolidinthegasaerosolandsoonundertheoperatingstatuses,thebackplatedesignhascertaininfluencetotheoverallsystemperformance,thestandardbackplate,thestandardimpellerstructurecanadaptthespecifictechnologicalrequirementnotnecessarily.Inrecentyearsappearedreferstotheshapebackplate,theovalcrosssectionbackplate,theconcaveshapebackplate,halfcauldronbackplateaswellasthereversepartbackplateandsoon,allaimsatthedifferentmixgoal,satisfieditsagitationrequest.Thusunderthenon-standardconditionimpeller,thebackplateandaffectmutually,becomestheagitationresearchtheimportantconstituent,andbecomesthecraftimprovementoneway.Thespecificagitationimpellerandthespecificformbackplatedesignunifies,maygivethemoreoutstandingshopcharacteristics.中文翻译机械搅拌槽挡板的研究机械搅拌槽的合理结构包括搅拌器的选择、搅拌槽结构以及挡板结构形式。任何安置于搅拌装置之外的槽内静止部件都构成挡板。因而挡板可分为两类：最常见的挡板形式是垂直安装于槽壁的构件，即壁挡板；另一类是特殊挡板，形状、位置各异，有底挡板、表面挡板等，换热管和插入槽内液面下的蒸气管、空气管和进料管等内部构件也能起到挡板作用。一、挡板的作用挡板的基本作用，是将液体的旋转运动改为垂直翻转运动，消除旋涡，同时改善所施加功率的有效利用率。挡板限制了液体的切向速度，增加了轴向和径向速度分量，其净化作用是使搅拌器排出流具有更宽的流动半径，搅拌器旋转所产生的排出流，因受槽壁和挡板的作用，在搅拌槽内形成复杂的流场，流型、速度大小和方向等均因搅拌器叶轮与挡板的相互作用而有所变化，混合效果得到显著加强。二、全挡板条件功率是搅拌器的特征参数。对于特定的搅拌器（叶轮形式和转速不变），功率随挡板系数的增大而增大。但当挡板系数达到一定数值时，功率不会进一步增大，而是基本保持恒定。此时的档板系数称为全挡板条件，即搅拌功率达到饱和。在搅拌槽的实际设计中，按照挡板宽度、数量的经验性规定，通常采用垂直于槽壁的4块宽度bd为D12D10的挡板（一般称之为“标准挡板”）来满足全挡板条件，这是因为根据公式（1），全挡板条件下的挡板尺寸、数量和形状并非最优。适当的挡板条件所提供的流型能够带动全槽的物料运动，确保充分混合；而过多的挡板，即搅拌槽的过挡板化，将减少总体流动，并将混合局限在局部区域，导致不良的混合性能。三、挡板对功率的影响在无挡板的搅拌槽中，任何类型的搅拌器，都将产生切向流并形成旋涡。设置挡板后，切向流受到抑制或阻碍，槽内产生上下翻动的大幅度运动，旋涡消除。标准挡板包含双重含义：功率饱和与旋涡消除。但标准挡板并非优化结构。1、搅拌功率的计算在湿法冶金过程中，搅拌器叶轮通常为桨式、推进式和涡轮式，2、挡板结构对功率准数的影响（1）理论分析根据搅拌器功率的流体力学基础分析，功率准数的物理意义是阻力系数。对于搅拌器叶轮而言，在充分湍流状态下，形状阻力是阻力的重要构成，因而功率准数取决于搅拌槽的几何结构。挡板给予不同的叶轮以不同的影响。（2）实验分析挡板增加了搅拌器功率的消耗，同时改进了混合效果。对于不同形式的桨叶，挡板影响不同。在相同介质条件下，使用不同形式的桨叶，在具有4种挡板结构的小型搅拌槽中进行实验（实验中nd4），得到一组功率准数，见表1。由表1的数据可以得到如下结构：挡板系数对产生径向流的桨叶（圆盘涡轮桨）影响最大，对同时产生径向流和轴向流的桨叶（折叶涡轮桨）次之，对产生轴向流的桨叶（螺旋桨）影响最小；对于同一类型的桨叶，挡板系数的增大，也导致功率准数的增加；当叶轮形式及挡板系数相同时，挡板结构的改进，同样可以改变功率准数，并在满足功率