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/Itwasnotuntilthelate1920sthatmineralhydraulicoilswereintroduced/Consequently/theoilbecamethemainpressuremediumofhydraulicapplications/Recently/thedemandforusingpuretapwater(excludingseawater)asapressuremediuminhydraulicapplicationshasincreasedduetoitsavailability/easymaintenance/itslowcostandhighsafetylevelsagainstpollutionandfirehazard/So/waterhydraulicscanbeusedinnewapplicationareassuchasfoodprocessing/pulpandpaperindustry/medicine/glassmaking/coalminingandnuclearindustry/Waterischaracterizedbyverylowviscosityincomparisonwithmineralhydraulicoils/Forexample/thekinematicsviscosityofwaterat40isabout0/72m/sandoftypicalmineraloilis322m/s/Keyproblemsshouldbeconsideredinwaterhydraulicsystem/Firstly/theverylowviscositymustincreasethedifficultyofdevelopinghydrodynamicfilmbetweenfrictionalpairs/andtheverysmallchangeofwatersviscositywithpressuremeansthatelastohydrodynamiclubricationwithhardmaterialsisunlikelytooccur/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/anewtypeofseawaterhydraulicpistonpumpswithbettersuctioncharacteristicshadbeendevelopedatHUST4/Muchofthisresearchhasconcentratedonnewmaterials/structureandexperiments/whicharespeciallyintroducedinthispaper/Meanwhile/theapplicationsonsomeaspectsforwaterhydraulicsarealsodescribed/1SEAWATERHYDRAULICAXIALPISTONPUMPATHUSTFigure1showstheschematicdiagramoftheseawaterhydraulicaxialpistonpumpatHUST/Itisaswashplateaxialseven-pistonpumpwithfixeddisplacement/whichcanworkwitheitherseawaterorrawwater/Thispumpsratingsare/flowrateupto40L/min/pressureupto14MPa/Thespecifiedpressureis10MPa/Theinletandoutletcheckvalveswithsoftsealsarerespectivelyassociatedwitheachpiston/onthepistonsuctionstroke/waterisdrawnbyvacuumfromtheinletportthroughtheinletcheckvalves/fillingthespaceattheleftsideofthepistons/Onthepistondischargestroke/thewaterisforcedtotheoutletportthroughtheoutletvalves/Togetbetterlubricationforthebearings/thedrivemechanismofthepumpislubricatedwithoilandtheoilchamberattherightsideofthepistonsiskeptseparatefromthedisplacementsidebyusingdoublepackingsealsaroundeachofthesevenpistons/Therefore/bearingsandtheswashplate/slipperpadfrictionpairsarelubricatedwithoil/Thepiston/cylinderborefrictionpairsarelubricatedwithrawwater/Fig/1SchematicDiagramoftheSeawaterAxialPistonPumpWhenusingrawwateraslubricant/duetorawwaterschemicallyactivenature/lowviscosity/poorlubricationandhighvaporpressure/theselectionofmaterialsused/playakeyroleindetermininglonglifespanforawaterhydraulicpump/Thefrontandrearcasings/cylinderblockaremadeofaluminum-alloywithanodizingtreatment/pistonsandcylinderlinersaremadeofstainlesssteel(1Cr18Ni9Ti)andreinforcedpolymerorreinforcedpolymer-eterketon(PEEK)/respectively/Thesealsofinletandoutletvalvesaremadeofpolytetrafluoroethylene(PTEF)andthepoppetswithsoftsealsaremadeofbronzedstainlesssteel/Inordertoreducethewearonasurface/materialswithlowfrictioncoefficientmustbeused/relativelynewpolymer/PEEKshowsaverylowfrictioncoefficient/about0/02/incontacttosteelwithawaterfilm4/Thisfrictioncoefficientiscomparablewith0/050/07forsteeltosteelwithmineraloil/Recently/PEEK/hasturnedtobecommonlyusedforslidingpartsinwaterhydraulicpumpandmotor/Inordertoreducethewearonasurface/materialswithlowfrictioncoefficientmustbeused/Arelativelynewpolymer/PEEKshowsaverylowfrictioncoefficient/about0/02/incontacttosteelwithawaterfilm4/Thisfrictioncoefficientiscomparablewith0/050/07forsteeltosteelwithmineraloil/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)Thetemperatureoffluidmediumiscontrolledintherangeof2040e/2/3TestprocedureTheaimofthetestwastodeterminethevariationofvolumetricefficiency/forthepump/withpressureandspeed/aswellasthecurvesofthepumpinletvacuumversusflowrate/UsuallyVolumetricefficiencycanbeusedtodescribetheperformancesofapump/Itisdefinedas/=0QQ100Whereisvolumetricdfficiency；Qisthedffective/averagedpumpdeliveryperunittime/L/min；Q0isthetheoretical/averagedpumpdeliveryperunit
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