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1、SteamEnginesNathanFiresheetsHistoryofSteamEngineInventorsusedexperimentaldevices,suchastherudimentarysteamturbinedevicedescribedbyTaqial-Dinin1551andGiovanniBrancain1629,todemonstratethepropertiesofsteam.Thefirstpracticalsteam-powered'engine'wasawaterpump,developedin1698byThomasSavery.Itpro
2、vedonlytohavealimitedliftheightandwaspronetoboilerexplosions,butitstillreceivedsomeuseforminesandpumpingstations.Thefirstcommerciallysuccessfulengine,theatmosphericengine,inventedbyThomasNewcomendidnotappearuntil1712.Newcomen'senginewasrelativelyinefficient,andinmostcaseswasonlyusedforpumpi
3、ngwater.HistoryofSteamEngineJamesWattdevelopedanimprovedversionofNewcomen'senginebetween1763and1775whichused75%lesscoalthanNewcomen's,andwashencemuchcheapertorun.Wattproceededtodevelophisenginefurther,modifyingittoprovidearotarymotionsuitablefordrivingfactorymachinery.Earlyengineswere"atmos
4、pheric",meaningthattheywerepoweredbythevacuumgeneratedbycondensingsteaminsteadofthepressureofexpandingsteam.Cylindershadtobelarge,astheonlyusableforceactingonthemwasatmosphericpressure.Steamwasonlyusedtocompensatefortheatmosphereallowingthepistontomovebacktoitsstartingposition.Evenifpressur
5、edsteamhadbeenavailable,itcouldnotdoanywork(push)againstthechainconnectingthepistontothebeam.EarlyWattSteampumpingengine.HistoryofSteamEnginesAround1800,RichardTrevithickintroducedenginesusinghigh-pressuresteam.Theseweremuchmorepowerfulthanpreviousenginesandcouldbemadesmallenoughfortranspor
6、tapplications.Thereafter,technologicaldevelopmentsandimprovementsinmanufacturingtechniques(partlybroughtaboutbytheadoptionofthesteamengineasapowersource)resultedinthedesignofmoreefficientenginesthatcouldbesmaller,faster,ormorepowerful,dependingontheintendedapplication.Steamenginesremainedth
7、edominantsourceofpowerwellintothe20thcentury,whenadvancesinthedesignofelectricmotorsandinternalcombustionenginesgraduallyresultedinthevastmajorityofreciprocatingsteamenginesbeingreplacedincommercialusage,andtheascendancyofsteamturbinesinpowergeneration.R
