外文翻译--润滑和摩擦学在海水水力活塞泵中的应用.doc
收藏
编号:96157
类型:共享资源
大小:280.50KB
格式:DOC
上传时间:2013-11-17
上传人:上***
认证信息
个人认证
高**(实名认证)
江苏
IP属地:江苏
6
积分
- 关 键 词:
-
教育专区
外文翻译
精品文档
外文翻译
- 资源描述:
-
附录二外文翻译英文文献lubricationandtribologyinseawaterhydraulicpistonpumpAbstract:Waterhydraulicsystemshaveprovokedmajorinterestbecauseofthehumanfriendlyandenvironmentalsafetyaspects.Pistonpumpisoneofthemostfrequentlyusedhydraulicunitsinrecentengineeringtechnique.Inwaterhydraulicpistonpump,poorlubricationismorelikelytohappenthaninoilhydrauliconebecauseofdifferenceinpropertiesbetweenwaterandoil.Sotherearesomekeyproblemssuchascorrosivewearanderosion,whichareinvestigatedbriefly.Manynewmaterialshavebeendeveloped,whichgivelongerlifeexpectancieswithwaterwithoutcorrosionanderosion.AnewtypeofseawaterhydraulicpistonpumpswithbettersuctioncharacteristicshadbeendevelopedatHUST.Muchofthisresearchhasconcentratedonnewmaterials,structureandexperiments,whicharealsospeciallyintroduced.Keywords:waterhydraulics;pistonpump;lubrication;test;materialINTRODUCTIONTheearliesthydraulicsystemsusedwaterasthehydraulicfluid.Thisrestrictedtheworkingtemperaturerangeandcausedcorrosionaswellaslubricatingproblems.Itwasnotuntilthelate1920'sthatmineralhydraulicoilswereintroduced.Consequently,theoilbecamethemainpressuremediumofhydraulicapplications.Recently,thedemandforusingpuretapwater(excludingseawater)asapressuremediuminhydraulicapplicationshasincreasedduetoitsavailability,easymaintenance,itslowcostandhighsafetylevelsagainstpollutionandfirehazard.So,waterhydraulicscanbeusedinnewapplicationareassuchasfoodprocessing,pulpandpaperindustry,medicine,glassmaking,coalminingandnuclearindustry.Waterischaracterizedbyverylowviscosityincomparisonwithmineralhydraulicoils.Forexample,thekinematicsviscosityofwaterat40isabout0.72m/sandoftypicalmineraloilis322m/s.Keyproblemsshouldbeconsideredinwaterhydraulicsystem.Firstly,theverylowviscositymustincreasethedifficultyofdevelopinghydrodynamicfilmbetweenfrictionalpairs,andtheverysmallchangeofwater'sviscositywithpressuremeansthatelastohydrodynamiclubricationwithhardmaterialsisunlikelytooccur.So,thelowviscosityisaccompaniedwithpoorlubricityofwater.Poorlubricitycancausecorrosivewearanderosionproblems.Secondly,itistobenotedthatwater(especiallyseawater)iselectricallyconductiveandmayactasanelectrolytewhenimpuritiesorcertainadditivesarepresent.Insuchcasestheelectrolyticcorrosionmayoccur.Thereforemetallicmaterialstobeusedinconnectionwiththewaterpressuremediumshouldcomplywiththeelectrochemicalseries.Fromthepresentpointofview,oilhasanadvantageagainstwaterintheaspectoflubricationbuttherecenttechnologyofmaterials,designsandtribologyhasbroughtthepossibilityofusingwaterasapressuremediumagain.Anumberofnewmaterials,suchasstainlesssteel,corrosionresistantalloy,ceramics,polymers,bronze,brass,anodizedaluminaandcomposites,etc.,havegoodcompatibilitywithwater,alongwithmoderndesignandmanufacturingtechniques,waterhydraulicsbecomemoreandmorepractical.Modernscienceandtechnologiescanprovideessentialtechnicalguaranteeforthereemergenceanddevelopmentofwaterhydraulics.Pistonpumpisoneofthemostfrequentlyusedhydraulicunitsinrecentengineeringtechniques.Inwaterhydraulicpistonpump,poorlubricationismorelikelytohappenthanthatinoilhydrauliconeInwaterhydraulicsystem,thefirstobjectiveistodeveloppistonpumpandmotorusingrawwateraspressuremedium.Todealwithproblemsofusingrawwateraslubricant,threecriticalslidingpairs,suchasthecylinderblock/portplate,piston/cylinderbore,swashplate/slipperpadhavebeenfocused.Waterpistonpump(motor)hasbeendevelopedinsomedevelopedcountries,suchasUSA,UK,Japan,Denmark,GermanyandFinland,etc.Pumpsandmotorsarevirtuallyidentical.TheFennercompanyintheUnitedKingdomhasdevelopedanaxialpumpforrawwaterwithfixeddisplacement.Thepumpsandmotorsareoftheswashplatetype.Bearingcentersaredesignedtobeinlinewiththetorquecentersoftheunitsinordertominimizetiltforcesonthevalveplate.Allrubbingsurfacesusepolymer-stainlessinterfaces.Anadaptationofthepumpusingceramicpistonshasoperatedsuccessfullyupto14MPa.Thecasingaremadeofstainlesssteel.TheHauhincoradialpistonpumpinGermanyhasfixeddisplacement.Thepumpdesignisbaseduponusingnewandnon-traditionalmaterialssothataseparatelubricationsystemisavoided.Themedium,industrialwater,tobepumpedalsoactsasalubricant.Typicallypumpratingsare:flowrateupto242L/min,pressureupto32MPa.TheDanfossNessiepumpoftypePHA(pumpaxialhigh-pressure)inDenmarkisdesignedasanintegralunitbasedupontheswashplateprinciple.Allfrictionsurfaces,suchascylinders,thrustplateandpistonshoes,aremadesolelyofreinforcedplasticorovermoldedstainlesssteel.Theouterhousingandendflangesaremadeofchronite-castedspecialbrassinordertopreventcorrosion.Thepumpisdesignedsothatthelubricationofthemovingpartsinthepumpismaintainedbythewateritself.Allthepartsinthepumparemadeofnon-corrosivematerials,ensuringalonglifeofthepump.Thepressurelevelofthepumpis16MPa.TheaxialpistonpumpintheFinnishcompanyHytarcanalsoactasamotoranditcanbeoperatedinnormaltapwaterandseawater.Thepressurelevelofthepumpis21Mpaandthelifespanisabout8000hAftertenyearsofresearchanddevelopmentonhighwaterbasedfluidhydraulics,anewresearchanddevelopmentprogramfortapwaterandseawaterhydraulicssupportedbyNationalScienceFoundationofChinawerecarriedoutatHuazhongUniversityofScience&Technology(HUST)from1990totoday.Recently,anewtypeofseawaterhydraulicpistonpumpswithbettersuctioncharacteristicshadbeendevelopedatHUST[4].Muchofthisresearchhasconcentratedonnewmaterials,structureandexperiments,whicharespeciallyintroducedinthispaper.Meanwhile,theapplicationsonsomeaspectsforwaterhydraulicsarealsodescribed.1SEAWATERHYDRAULICAXIALPISTONPUMPATHUSTFigure1showstheschematicdiagramoftheseawaterhydraulicaxialpistonpumpatHUST.Itisaswashplateaxialseven-pistonpumpwithfixeddisplacement,whichcanworkwitheitherseawaterorrawwater.Thispump'sratingsare:flowrateupto40L/min,pressureupto14MPa.Thespecifiedpressureis10MPa.Theinletandoutletcheckvalveswithsoftsealsarerespectivelyassociatedwitheachpiston,onthepistonsuctionstroke,waterisdrawnbyvacuumfromtheinletportthroughtheinletcheckvalves,fillingthespaceattheleftsideofthepistons.Onthepistondischargestroke,thewaterisforcedtotheoutletportthroughtheoutletvalves.Togetbetterlubricationforthebearings,thedrivemechanismofthepumpislubricatedwithoilandtheoilchamberattherightsideofthepistonsiskeptseparatefromthedisplacementsidebyusingdoublepackingsealsaroundeachofthesevenpistons.Therefore,bearingsandtheswashplate/slipperpadfrictionpairsarelubricatedwithoil.Thepiston/cylinderborefrictionpairsarelubricatedwithrawwater.Fig.1SchematicDiagramoftheSeawaterAxialPistonPumpWhenusingrawwateraslubricant,duetorawwater'schemicallyactivenature,lowviscosity,poorlubricationandhighvaporpressure,theselectionofmaterialsused,playakeyroleindetermininglonglifespanforawaterhydraulicpump.Thefrontandrearcasings,cylinderblockaremadeofaluminum-alloywithanodizingtreatment,pistonsandcylinderlinersaremadeofstainlesssteel(1Cr18Ni9Ti)andreinforcedpolymerorreinforcedpolymer-eterketon(PEEK),respectively.Thesealsofinletandoutletvalvesaremadeofpolytetrafluoroethylene(PTEF)andthepoppetswithsoftsealsaremadeofbronzedstainlesssteel.Inordertoreducethewearonasurface,materialswithlowfrictioncoefficientmustbeused.relativelynewpolymer,PEEKshowsaverylowfrictioncoefficient,about0.02,incontacttosteelwithawaterfilm[4].Thisfrictioncoefficientiscomparablewith0.05~0.07forsteeltosteelwithmineraloil.Recently,PEEK,hasturnedtobecommonlyusedforslidingpartsinwaterhydraulicpumpandmotor.Inordertoreducethewearonasurface,materialswithlowfrictioncoefficientmustbeused.Arelativelynewpolymer,PEEKshowsaverylowfrictioncoefficient,about0.02,incontacttosteelwithawaterfilm[4].Thisfrictioncoefficientiscomparablewith0.05~0.07forsteeltosteelwithmineraloil.Recently,PEEK,hasturnedtobecommonlyusedforslidingpartsinwaterhydraulicpumpandmotor.1EXPERIMENTAL2.1TestapparatusInordertoexaminethefunctionsofthispump,anexperimentalstudyisinprogress.Thetestpumpisdrivenbyanelectricmotor.Tostudythefunctionsofthispumpatdifferentpumprotation,whichwascontrolledbyadjustmentsinelectriccabinet.Thereliefvalvecanbeusedtoprotectthesystem.Thethrottleisusedasloadingunitforthetestpump.Thecoolercontrolsthetemperatureofthesystem.Allhydrauliccomponentsweredesignedbyourselves.2.2ExperimentalmethodThetestmethodisdescribedasfollows.Eitherrawwater(puretapwater)orseawater(imitationseawater)canbeusedaspressuremedium.Theimitationseawatercanbemadeupaccordingtothestandard(ASTMD21142252)oftheUnitedStatesofAmericaThatthemainfeaturesofthetestsweredecidedasfollows:(a)Theloadingpressureshouldbeadjustedupto14MPa.(b)Thespeedofrotationshouldbefullyvariableupto1000r/min.(c)Afterspeedreachesasteadystate,waterpressureandtheflowrateshouldberecorded.(d)Thetemperatureoffluidmediumiscontrolledintherangeof20~40e.2.3TestprocedureTheaimofthetestwastodeterminethevariationofvolumetricefficiency,forthepump,withpressureandspeed,aswellasthecurvesofthepumpinletvacuumversusflowrate.UsuallyVolumetricefficiencycanbeusedtodescribetheperformancesofapump.Itisdefinedas:=0QQ100℅Whereisvolumetricdfficiency;Qisthedffective,averagedpumpdeliveryperunittime,L/min;Q0isthetheoretical,averagedpumpdeliveryperunit
- 内容简介:
-
-
- 温馨提示:
1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
人人文库网所有资源均是用户自行上传分享,仅供网友学习交流,未经上传用户书面授权,请勿作他用。