文献翻译-管壳式与板式水水换热器的比较分析

5翻译5.1英文原文Shell-and-tubeandplateheatexchangerwaterComparativeAnalysisAbstract:Throughtheclosedcyclecoolingwatersysteminthewaterwaterheatinterchangershaping,indetailelaboratedtheshelltypeandthedischeatinterchangerstructureperformancetechnologyeconomycompares,providesthereferenceforthewaterandwaterheatinterchangershaping.Keyword:HeatinterchangerperformancecomparisonFromthedomesticpowerplantshavebeenbuilt,forclosed-cyclecoolingwatersystemofwaterheatexchangertwocategories.isashellandtubetypeheatexchangers,andtheotheristheplateheatexchanger.Shellheatexchangerisusedintheformofheatexchangerintheplantdesignhasbeenwidelyused,Insomedomesticunitsoftheplantimports,thegas-steamcombinedcyclepowerplantsandnuclearpowerplantsaremoreusedplateheatexchanger.Plateheatexchangerasacompact,lightweight,highheattransferefficiency,andthepeopleareinterestedingrowing.Thispapershell-and-tubeheatexchangerplateandtwokindsofstyles,andmakeselectionsuggestions1.Aplateandshellheatexchangerstructurebrief(1)ShelltypeheatinterchangerShell-and-tubeheatexchangeristheformerMarineRoom,probation,cylinder,thewaterroomandsoon.Controltheuseofpumped-Bundle,whichconsistsofaroundtubesheet,Baffled,thestick,distancecontrol,Tubecomponents.Stickwiththemanagementboard,demolitionoftheplatesusingscrewconnectiontubeandtubesheetadoptedinflationacceleratingsealedwelding.Intheshellsideentrancetothecontrolofwateronboard-equippedtopreventthecoolingwaterwashedTube.Inordertoreducetheloadortotakecontrolofthecylinderfriction,withthecontrolontheslide.Roomforcleaninguptherubbish,sedimentandtheblockageofthetubesinthewateraroundtheroomontheCoverofaninspectionhole.Tomonitorwaterheatexchangerperformance,inthecoolingwaterside(exceptsaltwaterside)andthecoolingwaterside(ofseawater)fortheimportandexportareequippedwithatemperatureandpressuremeasurement,Thereisalsosupposedtoexhaustandinterfaces.(2)Plateheatexchangerplateheatexchangerconsistsofasetofparallelcorrugatedsheetmetalcomponents,Platesinthefourcornerhaveaccesshole,Clampingplatewasinconnectionwithanaspectofthefixedplatecompactorandactivitiesintheframeworkofplateandclampingboltsusedtobeclamping.Connectingwiththeboardofthechannelporeright,andwithtwoheatexchangeliquidexternalpipingconnectedHeatplatecompactorandactivitiesflagatthetopplatebearingbeamsbelowitfromthebottomofthebeamsattheposition.Plateheatitselfisaspecificshapesurroundedbysolid-tightgasketsealtopreventexternalleakage.andthetwoheatexchangeliquidformbyalternatingcurrenttoflowthroughanotherpairofplateheattransferbetweenthechannel.Platesofcorrugatednotonlyimprovesthefluidturbulence,andcreatingmanypointsofcontacttowithstandnormaloperatingpressure.Fluidflow,physicalproperties,thepressureandtemperaturedifferentialdecisionoftheplatenumberandsize.2HeatinterchangersdesignconditionsHeatexchangerdesignoftheplantfromthestarttomeetthegreatestcontributiontothevariousloadoperatingconditionstotakedollars,andleaveenoughmargintoensureheatexchangerinthemaximumloadandmaximuminlettemperatureandthelargestFouling,intherepaircycle,itwastobegiventhetaskofcooling.Domesticimported300MWcoal-firedunitsasanexample.Coolingequipmentrequirementsofthecoolingwaterinlettemperatureislessthan37.5C,fromthecoolingequipmentwasheatingupoverthecoolingwatertemperatureisabout42.83Shellstypesanddischeatinterchangercomparison3.1FlowstheheattransferdesigncomparisonShell-and-tubeheatexchangertubeheatexchangerisanessentialcomponent,Ittubeinafluidflowingthroughthetubeandanotherprovidingheattransferfluidbetweenthesurface.Accordingtoboththefluidnatureofpipematerials,willbecorrosive,low-qualitywateronthewaterpipeflowInadditiontobetterwaterqualitybrineontheshellsideofthetubes,suchtubesonlyusedseawatercorrosion-resistanttitaniumtube.Meanwhilemoreconvenientcleaningdirtdiameterfromthepointofviewofheattransferfluiddynamics,giventheuseoftheshellofsmalldiametertubescanbegreaterdensityonthesurface,butmostfluidinthetubesonthesurfacedirtlayerdeposition,Inparticular,thecoolingtubepoorwater,siltanddirtandseaorganismsexist,arelikelytobeformedonthewallofsediments,willenableheattransferdeteriorationregularcleansingbecomesnecessary,tubecleaningrestrictionssmallestdiameterofabout20mm,TitaniumTubegeneral,25mm,therighttothefluid,formedmainlybydirtwalltemperatureandvelocityimpacttobereasonablemaintenancecycle,thewaterinsidethetubevelocityintwo1961(astoallowpressuredroprequirements).Asgeneraluseseawatercoolingwater,theriver,pronetocausingscalingtheshell-and-tubeheatexchanger,Watershouldbeequippedconcentrationofplasticballcleaningdeviceforcleaning.Plateheatexchangerinthecoolingwaterandcoolingwateronbothsidesofthecorrugatedplateconvection,usingcorrugatedchevronBellows,Thesecorrugatedplateheattransferbias,thatisadjacenttotheheatplatewiththesameangleofinclinationanddirectionofthebellows.Crosssectionalareaalongthedirectionofflowisconstant,butduetothechangingdirectionofflowresultingflowshapechange,whichleadstoturbulence.Heatgeneralcorrugatedplatedepthof3-5mm,theturbulentflowisabout0.11.0to1.4msBellowsthinplatethickness0.61mmandtheadjacentcubicletohavemanypointsofcontacttowithstandnormaloperatingpressureadjacenttotheboardsoppositedirectionofthechevrontrench,twogroovesontheintersectionpointofcontactformation,thiscanalsoeliminatevibration,andthepromotionoftheexchangeofheatandturbulenceatthesametime,eliminatefatiguecracksasaresultoftheinternalleakage.Chevroncorrugatedplateturbulenthigher,highturbulencecanplayafullroleincleaning,canbeparticularlyeffectivedepositiondirtminimized,butcorrugatedboardmorepointsofcontact,whenliquidwaterqualitypoor,containingsuspendedsolidparticles,debrisandweeds,etc.,becauseofthenarrowgapplate.Sototheextentpossible,ensurethatallparticlesabove2mmintotheheatexchangerinthepast,muststrip,Ifthefiltercaneffectivelyplayarole,itiseasytoplug.3.2HeattransfercoefficientscomparisonShellheatexchangertube,ahorizontalfluidpassingthroughthetubewallandpipeflowofaheattransferfluid,mutualverticalcross-flowheattransfercoefficientisgenerally10003000w/(m2.k).Plateheatexchanger,thecoolingwatersidewiththesideofthecoolingwaterflowuniformityturbulence,thetworeversefluidflowAstherippleeffectcausedturbulence,resultinginhigherheattransferrate,highresistancetopressureandhighshearstressfield.Thiswillleadtoinhibitheattransfersurfaceofthedirtformed.Heattransfercoefficientisgenerally35005500w/(m2.k),whichcansaveheatexchangerheattransferarea.3.EndsdifferencecomparisonShell-and-tubeheatexchangertemperaturedifference(thatis,thecoolingwaterinlettemperatureandthecoolingwateroutlettemperaturedifference)5.Plateheatexchangerduetoitsstructuralcharacteristicscanbedonetotheeconomyaslowas1Ctemperaturedifference.3.4CoolingwatervolumecomparisonShell-and-tubeheatexchangergeneralcoolingandwatercoolingwaterthana1.22.5:1.Plateheatexchanger,astwokindsofmediaflowwiththesamehighheattransferefficiency,Thereforeplateheatexchangercangreatlyreducethecoolingwater,thegeneralcoolingwaterandcoolingwaterthana0.81.1:1,thusreducingpipevalvesandpumpsinstalledoperatingcosts3.5InstallmentsoverhaulscomparisonPlateheatexchangerissmallinsize,lightweightcharacteristics,maintenanceconvenience,withoutliftingbasedmaintenancefacilities,Therefore,theinstallationoccupiesless.Plateheatexchangerincludingtheartificialmaintenanceunitpackswillbeopened,usingwatergunsandbrushcleaningplatesandgaskets,checkplategasketand,ifnecessary,replacetheplateandgasket.Plateheatexchangergenerallyatimetoclean,andwhetherornottheactualneedstobedone.Whentheapplicationoftheriver,poorwaterquality,suchascoolingwater,siltanddirtbecauseoftheexistence,andtherapidgrowthofmicroorganismshavecausedpollutionandthesurfaceplugdanger.Overseas,theapplicationofwaterforcoolingwater,cleaninghighfrequency,theaverageannual3.3.Shell-and-tubeheatexchangertubebundleiscomposedofitsownweightislargervolume,maintenanceofthepumpingrequiredtostayoutofcontrolaslongdistance,itoccupiesmoreneededwiththenecessaryliftingoverhaulfacilities.Shell-and-tubeheatexchangerdesignlife-expectancyof30years,overhaulcyclefouryears,whenheatexchangerleaked,(probablytubesandtubeplateoftubeleakageorrupturecausedbytheleakage)canbeusedtoplugthepiperecoveryinashortperiodoftimeMinuteperformance,shell-and-tubeheatexchangerallowstheblockingof7%margin.Forpipecleaningmayneedplasticballcleaningdeviceforthemechanicalcleaningregularly.4HeatinterchangersindomesticpowerplantmovementsituationMyearlycommissioningofthe300MWcoal-firedunitsclosedcoolingwatersystemsarechosenshell-and-tubeheatexchangerwater.runningrelativelywell.Inrecentyears,becauseofthecontinuousadvancementoftechnology,designoptimization,shell-and-tubeexchangerscoverswater,Maintenanceoflargevenuesinthemainshortcomingsoftheplantlayoutoptimizationmoreprominent,Insomecirculatingwatersystemforsecondarycoolingwatercirculationunit,takingintoaccountthewatercoolingheatexchangeroftherelativelygoodwaterquality,Impuritieslesspollutionandthesmallscreenstructureofcontinuousimprovement,closedcoolingwatersystemsalsouseplateheatexchanger.5ConclusionOnshell-tubeandplateheatexchangerthecomparisonmaycometothefollowingconclusions:Plateheatexchangerforhighheattransferefficiency,smallsize,lightinweightdismounting,whencoolingwaterbetter,Itisanidealheatexchangerequipment.Butforalargenumberofcoolingwatersedimentanddirt,suchasthepresenceofwater,thefilterscannoteffectivelyplayitsroleitiseasytoplug,resultinginfrequentcleansingaffectthesafeoperationoftheunit.译文：管壳式与板式水水换热器的比较分析摘要：通过闭式循环冷却水系统中水水换热器的选型，详细论述了管壳式与板式换热器的结构性能技术经济比较，为水水换热器的选型提供参考。关键词：换热器性能比较从国内已建发电厂来看，用于闭式循环冷却水系统的水水换热器有两类，一类是管壳热换器，另一类是板式换热器。管壳换热器是常用的换热器形式，在电厂设计中已得到了广泛的应用，而在国内一些进口机组的电厂、燃气蒸汽联合循环电厂和核电站多有采用板式换热器。由于板式换热器紧凑、重量轻、高传热效率，人们对它的兴趣日益增长。本文针对管壳式及板式换热器二种型式进行比较，并提出选型参考意见。1管壳式及板式换热器结构简介（1）管壳式换热器管壳式换热器是由前水室、管束、筒体、后水室等组成。管束采用可抽式管束，它由前后管板、折流板、拉杆、定距管、换热管组成。拉杆与管板、拆流板采用丝扣连接，换热管与管板采用胀接加密封焊。在壳侧水入口处的管束上设置防冲板，以防止被冷却水直接冲刷换热管。为了减少管束装入或抽出筒体时的摩擦力，在管束上设有滑轨。为了检查清理室中垃圾、泥沙及管子的堵塞等，在前后水室端盖上设有检查孔。为了监视水水换热器的运行情况，在被冷却水侧（除盐水侧）及冷却水侧（海水侧）进出口都设置温度和压力测点，此外还设有排气和放水接口等。（2）板式换热器板式换热器是由一组波纹形的平行金属板构成的，在板片的4个拐角处都有通道孔，板被夹紧在一个侧面附有连接管的固定板和活动压紧板的框架中，并用夹紧螺栓加以夹紧。这些连接管同板上的通道孔对中，并与热交换的两种液体的外部管路相连，传热板和活动压紧板悬挂在顶部承载梁的下面并由底部横梁使其对准定位。传热板本身是有其有特定形状并被固紧的垫片密封，以防止外部泄漏，并把热交换的两种液体按逆流方式交替地流过另一对传热板之间的通道内。板片上的波纹不但提高流体的湍流程度，并且形成许多接触点，以承受正常的运行压力。流体的流量、物理性质，压降和温度差决定了板片的数目和尺寸。2换热器设计条件换热器设计应满足电厂从起动到最大出力时各种负荷下的运行需要，并留有一定的裕量，保证换热器在最大负荷、最高进水温度和最大污垢热阻时，在规定的检修周期内，仍能完成给定的冷却任务。以国产引进型300MW燃煤机组为例，各冷却设备要求冷却水进水温度不大于375，从冷却设备出来被加热过的冷却水最高温度约为428.3管壳式及板式换热器的比较31流动传热设计比较管壳式换热器的管子是换热器的基本构件，它为在管内流过一种流体和穿越管外的另一种流体之间提供传热面。根据两侧流体的性质决定管子材料，将具有腐蚀性，水质差的海水放在管内流动，水质较好的除盐水放在管子外壳侧，这样管子只需采用耐海水腐蚀的钛管，同时清洗污垢较为方便，管径从传热流体力学角度考虑，在给定壳体内使用小直径管子，可以得到更大的表面密度，但大多数流体会在管子表面上沉积污垢层，尤其管内冷却水水质较差，泥沙和污物及海生物的存在，都可能会在管壁上形成沉积物，将传热恶化并使定期的清洗工作成为必要，管子清洗限制管径最小约为20mm，钛管一般采25mm，对给定的流体，污垢形成主要受管壁温度和流速的影响，为得到合理的维修周期，管内侧水的流速应在2ms左右（视允许压降的要求）。由于一般冷却水选用海水、河水等，较易引起结垢，对管壳式换热器，应根据水质含沙量情况需设置胶球清洗装置进行定期清洗。板式换热器的冷却水和被冷却水在波纹板的两侧对流，波纹采用人字形波纹，这些传热板的波纹斜交，即在相邻的传热板上具有倾斜角相同而方向不同的波纹。沿流动方向横截面积是恒定的，但是由于流动方向不断变化致使流道形状改变，而引起湍流。一般传热板的波纹深度为35mm，湍流区流速约为0.11.0ms，波纹板很薄，厚度为061mm，相邻板间要有许多接触点，以承受正常的运行压力，相邻的板有相反方向的人字形沟槽，两种沟槽的交叉点就形成接触点，这样还可消除振动，并且在促进湍流和热交换的同时，消除了由于疲劳裂缝引起的内部泄漏。人字形波纹板湍流度较高，高湍流还能充分发挥清洗作用，可以特别有效的将沉积污垢减至最小，但是波纹