螺杆压缩机的设计外文文献翻译中英文翻译外文翻译.docx

螺杆压缩机的设计外文文献翻译中英文翻译外文翻译.docx

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螺杆压缩机的设计外文文献翻译中英文翻译外文翻译

英文原文

ScrewMachineDesign

Holmes,1999reportedthatevenhigheraccuracywasachievedonthenewHolroydvitrifyingthread-grindingmachine,thuskeepingthemanufacturingtoleranceswithin3μmeveninlargebatchproduction.Thismeansthat,asfarasrotorproductionaloneisconcerned,clearancesbetweentherotorscanbeassmallas12μm.

Screwmachinesareusedtodayfordifferentapplicationsbothascompressorsandexpanders.

Fig.1.4.Screwcompressormechanicalparts

Fig.1.5.Crosssectionofascrewcompressorwithgearbox

Foroptimumperformancefromthemaspecificdesignandoperatingmodeisneededforeachapplication.Hence,itisnotpossibletoproduceefficientmachinesbythespecificationofauniversalrotorconfigurationorsetofworkingparameters,evenforarestrictedclassofmachines.

Industrialcompressorsarerequiredtocompressair,refrigerantsandprocessgases.Foreachapplicationtheirdesignmustdiffertoobtainthemostdesirableresult.Typically,refrigerationandprocessgascompressors,whichoperateforlongperiods,musthaveahighefficiency.Inthecaseofaircompressors,especiallyformobileapplications,efficiencymaybelessimportantthansizeandcost.

Oilfreecompressedairisdeliveredalmostexclusivelybyscrewcompressors.Thesituationisbecomingsimilarforthecaseofprocessgascompression.Inthefieldofrefrigeration,reciprocatingandvanecompressorsarecontinuouslybeingreplacedbyscrewandadramaticincreaseintheneedsforrefrigerationcompressorsisexpectedinthenextfewyears.

Therangeofscrewcompressorssizescurrentlymanufacturediscoveredbymalerotordiametersof75to620mmandthispermitsthedeliveryofcompressedgasflowratesof0.6m3/minto600m3/min.Apressureratioof3.5isattainableinthemfromasinglestagefordrycompressorsandupto15foroilfloodedones.Normalpressuredifferencesareupto15bars,butmaximumpressuredifferencessometimesexceed40bars.Typically,foroilfloodedaircompressionapplications,thevolumetricefficiencyofthesemachinesnowexceeds90%andthespecificpowerinputhasbeenreducedtovalueswhichwereregardedasunattainableonlyafewyearsago.

1.1ScrewCompressorPractice

TheSwedishcompanySRMwasapioneerandtheyarestillleadersinthefieldofscrewcompressorpractice.Othercompanies,likeCompairU.K.,Atlas-CopcoinBelgium,Ingersol-RandandGardnerDenverintheUSAandGHHinGermanyfollowthemclosely.York,TraneandCarrierleadinscrewcompressorapplicationsforrefrigerationandairconditioning.Japanesescrewcompressormanufacturers,likeHitachi,MycomandKobe-Steelarealsowellknown.ManyrelativelynewscrewcompressorcompanieshavebeenfoundedintheMiddleandFarEast.NewmarketsinChinaandIndiaandinotherdevelopingcountriesopennewscrewcompressorfactories.AlthoughnotdirectlyinvolvedincompressorproductiontheBritishcompany,Holroyd,arethelargestscrewrotormanufacturer,theyareworldleadersintooldesign

andtoolmachineproductionforscrewcompressorrotors.

Despitetheincreasingpopularityofscrewcompressors,publicknowledgeandunderstandingofthemisstilllimited.ThreescrewcompressortextbookswerepublishedinRussianintheearlynineteensixties.Sakun,1960givesafulldescriptionofcircular,ellipticandcycloidalprofilegenerationandareproduciblepresentationofaRussianasymmetricprofilenamedSKBK.The

profilegenerationinhisbookwasbasedonanenvelopeapproach.Andreev,1961repeatsthetheoryofscrewprofilesandmakesacontributiontorotortoolprofilegenerationtheory.Golovintsov’stextbook,1964,ismoregeneralbutitssectiononscrewcompressorsisbothinterestingandinformative.Asomov,1977,alsoinRussian,gaveareproduciblepresentationoftheSRMasymmetricprofile,fiveyearsafteritwaspatented,togetherwiththeclassicLysholmProfile.

TwotextbookshavebeenpublishedinGerman.Rinder,1979,presentedaprofilegenerationmethodbasedongeartheorytoreconstructtheSRMasymmetricprofile,sevenyearsafteritwaspatented.Konka,1988,publishedsomeengineeringaspectsofscrewcompressors.OnlyrecentlyanumberoftextbookshavebeenpublishedinEnglish,whichdealwithscrewcompressors.O’Neill,1993,onindustrialcompressorsandArbon,1994,onrotarytwinshaftcompressors.Thereareafewcompressormanufacturers’handbooksonscrewcompressorsandanumberofbrochuresgivingusefulinformationonthem,buttheseareeitherclassifiedornotinthepublicdomain.Someofthem,liketheSRMDataBook,althoughavailableonlytoSRMlicensees,arecitedinliteratureonscrewcompressors.

Thereisanextraordinarilylargenumberofpatentsonscrewcompressors.Literallythousandshaveappearedinthepastthirtyyears,ofwhichSRM,alone,holds750.Thepatentsdealwithvariousaspectsofthesemachines,butespeciallywiththeirrotorprofiles.TheSRMpatentsofNilson,1952,forthesymmetricprofile,Shibbie,1979,fortheasymmetricprofileandAstberg1982,forthe“D”profilearethemostwidelyquotedinreferenceliteratureonthistopic.Ohman,1999,introducedthe“G”profileforSRM.Otherexamplesofsuccessfulprofilingpatentsmayalsobementioned,namely:

Atlas-Copco,CompairwithHough,1984,GardnerDenverwithEdstroem,1974,HitachiwithKasuya,1983,andIngersoll-RandwithBowman,1983.Morerecently,severalhighlysuccessfulpatentsweregrantedtorelativelysmallcompaniessuchasFuSheng,Lee,1988,andHanbel,Chia-Hsing,1995.Anewapproachtoprofilegeneration,usingarackasthebasisfortheprimarycurves,wasproposedbyRinder,1987,andStosic,1996.

Allpatentedprofilesweregeneratedbyaprocedurebutinformationonthemethodsusedishardlydisclosedeitherinthepatentsorinaccompanyingpublications.Thusittookmanyyearsbeforetheseproceduresbecameknown.Examplesofthisare:

Margolis,whopublishedhisderivationofthesymmetriccircularprofilein1977,32yearsafterithadbeenpatentedandRinder,whousedgearmeshingcriteriatoreproducetheSRMasymmetricprofilein1979,9yearsafterpatentpublication.ItmayalsobementionedthatTang,1995,derivedtheSRM“D”profileanalyticallyaspartofaPhDthesis13yearsafterthepatentpublication.Manyotheraspectsofscrewcompressorswerealsopatented.Theseincludenearlyalltheirmostwellknowncharacteristics,suchas,oilflooding,thesuctionanddischargeportsfollowingtherotortiphelices,axialforcecompensation,unloading,theslidevalveandtheeconomiserport,mostofwhichwerefiledbySRM.However,othercompanieswerealsokeentofilepatents.Thegeneralimpressiongainedisthatpatentexpertsareasimportantforscrewcompressordevelopmentasengineers

Thereisasurprisinglackofscrewcompressorpublicationsinthetechnicalliterature.Lysholm’spapersin1942and1966wereamidtwentiethcenturyexception,buthedidnotincludeanydetailsoftheprofilingdetailswhichheintroducedtoreducetheblow-holearea.Thus,journalpaperslikethoseofStosicetal.,1997,1998,mayberegardedasanexception.Inrecentyears,publicationofscrewcompressormaterialsinjournalshasbecomemorecommonthroughtheInternationalInstitutionofRefrigerationStosic,1992andFujiwara,1995,theIMechE,withpapersbySmith,1996,Fleming,1994,1998andStosic1998,andtheASME,byHanjalic,1997.Togetherthesemademoreinformationavailablethanthetotalpublishedinallpreviousyears.Stosic’s,1998paperisatypicalexampleofthemodernpracticeoftimelypublishing.

Therearethreecompressorconferenceswhichdealexclusivelyorpartlywithscrewcompressors.Thesearethebiennialcompressortechnologyconference,heldatPurdueUniversityintheUSA,theIMechEinternationalconferenceoncompressorsandtheirsystems,inEnglandandthe“VDISchraubenkompressorenTagung”inDortmund,Germany.Despitethenumber

ofpapersonscrewcompressorspublishedattheseevents,onlyafewofthemcontainusefulinformationonrotorprofilingandcompressordesign.TypicalPurduepaperscitedaspublicationsfromwhichareadercangaininformationonthisare:

Edstroem,1992,Stosic,1994andSingh,1984,1990.Zhang,1992,indicatesthattheyusedenvelopetheorytocalculatesomegeometricfeaturesoftheirrotors.TheDortmundproceedingsgivesomeinterestingpaperssuchasthatbyRinder,1984,whopresentedtherackgenerationofascrewrotorprofile,includingafullyreproduciblepatternbasedongeartheory.Hanjalic,1994andHolmes,1994,givemoredetailsonprofiling,manufacturingandcontrol.Kauder,1994,1998andStosic,1998aretypicalexamplesofsuccessfuluniversityreseachappliedtorealengineering.Sauls,1994,1998,mayberegardedasanexampleoffineengineeringwork.TheLondoncompressorconferenceincludedsomeinterestingpaperslikethoseofEdstroem,1989andStosicetal.,1999.

Manyreferencetextbooksongearsgiveusefulbackgroundforscrewrotorprofiling.Howeverallofthemarelimitedtotheclassicalgearconjugateactioncondition.Litvin,1968and1956–1994mayberegardedasanexceptiontothispractice,ingivinggearingtheorywhichcanbeapplieddirectlytoscrewcompressorprofiling.

1.2RecentDevelopments

Theefficientoperationofscrewcompressorsismainlydependentonproperrotordesign.Anadditionalandimportantrequirementforthesuccessfuldesignofalltypesofcompressorisanabilitytopredictaccuratelytheeffectsonperformanceofthechangeinanydesignparametersuchasclearance,rotorprofileshape,oilorfluidinjectionpositionandrate,rotordiameterandproportionsandspeed.

Now,whenclea