航空发动机专业英语之航空发动机部件介绍

2020/2/161CHAPTER2Propulsion2.1Introduction航空发动机专业英语第2页2020/2/16IntroductionPropulsionisthescienceofdesigninganenginetopropelavehicleforwardorup.Foraviation,propulsionisgenerallybrokeninto2categories:air-breathingpropulsionforairplanesandrocketpropulsionforspacecraft.Bothworkontheprincipleofpushinghighvelocityexhaustgasesoutthebackend(reactionthrustprinciple),buttheydifferinonesignificantdetail.Anair-breathingengineusestheairsteaminwhichtheairplaneisflyingtoaugmentthepropulsiveabilitiesoftheenginesoitcancarrylessfuel.航空发动机专业英语第3页2020/2/16Arocketenginetravelsinspacewherethereisnoair,andthereforeitmustcarryallitsfuelinternally.Anair-breathingenginewillhavebothaninletandanexit,whiletherocketwillbeclosedinthefrontandonlyhaveanexit.Ingeneral,anair-breathingenginewillgetmorethrustforlessfuelthanarocket.Propulsion推进,推进力航空发动机专业英语第4页2020/2/16aviation航空,航空学spacecraft航天器,宇宙飞船significant重要的,重大的augment增大,增加,扩大internally内部的Theforcesofflight(lift,drag,weight,andthrust)werediscussedintheFundamentalschapter.Thrustistheforwardfacingforcegeneratedbytheenginesoftheairplane.航空发动机专业英语第5页2020/2/16Theairflowsintotheengineatroughlytheflightspeedoftheairplane,anditexitstheengineflowingmuchhotterandfaster.Thethrustiscomputedusingtherateofmassflowingthroughtheenginetimesthedifferencebetweenthehighvelocityoftheexhaustgasesandtheoriginalvelocityoftheairintotheinlet.Theexhaustgasesflowoutthebackoftheengine,causingareactionforceontheairplane,pushingitforward.Thisconceptiscalledthereactionthrustprinciple.航空发动机专业英语第6页2020/2/16Fundamentals基本的,基础的roughly粗糙地,粗暴地Aneasywaytodemonstratethisprincipleistotakeaballoonandblowitup,fillingitwithhighpressureair.Iftheopeningoftheballoonispointedtothesideandallowedtoopen,thehighpressureairinsideescapesathighvelocitytothelowerpressureairoutside.Theairflowistotheside,buttheballoonexperiencesapush,orreactionthrust,intheoppositedirection.航空发动机专业英语第7页2020/2/16demonstrate证明,示范experience感受HistoryTheideaofusingthereactionthrustprincipleforpropulsionisnotnew.HeroofAlexandriadesignedatypeofsteamturbinecalledanaeolipileabout2000yearsago.TheChinesehaveusedblack-powder(gunpowder)rocketssincethetwelfthcentury(startingatabout1150AD).航空发动机专业英语第8页2020/2/16Fig.1-4Hero’sengine–probablytheearliestformofjetreaction.航空发动机专业英语第9页2020/2/16SirIsaacNewtonformulatedhislawsofdynamicsin1687,andthesewereusedtoexplainthewaythereactionthrustprincipleactuallyworked.Alexandria亚历山大IsaacNewton艾萨克.牛顿lawsofdynamics动力学定律航空发动机专业英语第10页2020/2/16In1791,JohnBarberofEnglandwasgrantedthefirstpatentforagasturbine,butitsalmost100yearsbeforethenecessarymaterials,designs,andmanufacturingtechniquesmadeitsapplicationfeasible.Earlyair-breathingenginesusedasmallgasenginetopoweralargepropellertohelpspeeduptheairtogeneratethrust.TheWrightflyerusedapropellerengine,Unfortunately,apropellerdrivenengineislimitedtoonlyslowerspeeds.航空发动机专业英语第11页2020/2/16Inordertoflyfaster,toapproachthespeedofsoundandgobeyondit,anotherdesignofair-breathingenginewasneeded.feasible可实行的，做得到的，合理的air-breathing空气吸入式pursue寻求，从事combustor燃烧室maiden初次的，无经验的航空发动机专业英语第12页2020/2/16TwoseparateeffortstodesignanewtypeofenginewerepursuedbyEnglishandGermanengineersinthe1930’s,InEngland,FrankWhittlewasworkingonthedevelopmentofajetengineusingtheconceptofaninternalpropellerorfanrunbyaturbinewithacombustorinbetweenthetwocomponents(seenextsectionfordefinitions).Hesuccessfullydemonstratedhisdesignin1939,andin1941thefirstBritishjetaircrafttheGlosterMeteor,madeitsmaidenflightusingthewhittlejetengine.航空发动机专业英语第13页2020/2/16Meanwhile,completelyseparatelyinGermany,Hansvon0hainwasseekingtoobtainthesamedesigngoaltoreducethenoiseandvibrationofthecurrentairplanescausedbyverylarge,heavyengines,Hethoughthecoulddecreasetheweightandsizeofanengineandincreasethespeedbyusingacompressor(atypeoffan)andaturbineinthesameshaft.HeandMaxHahn,themechanicwhoworkedonhiscar,workedforairplanebuilderErnstHeinkel.航空发动机专业英语第14页2020/2/16TheydemonstratedtheirfirstsuccessfulflighttestinaHeinkelHe178testaircraftin1938.Thus,bothEnglandandGermanyenteredthejetaircraftage!vibration振动shaft轴mechanic机械工，技工航空发动机专业英语第15页2020/2/16Sincethen,manyimprovementsandvariationsofjetenginedesignshavebeendeveloped.Inaddition,thelighter,moreefficientjetenginesimpactedthedesignoffaster,largerairplanes.Inunder100years,airplaneshavegonefromtheWrightflyeranditsfirstflightof12secondsand120feettosupersonicaircraftthatflyallovertheglobein3hours.Amajorcontributiontothisprogressisthedevelopmentofbetterair-breathingengines航空发动机专业英语第16页2020/2/16variation变化，变动lighter引燃器，点火器impact使有影响力，冲击，压紧的航空发动机专业英语第17页2020/2/162.2ComponentsThebasiccomponentsofanair-breathingenginearetheinlet,acompressororfan,thecombustor(burner),aturbine,andanexitnozzle.Differentengineswillusethesecomponentsinvariouscombinations,andsomewillexcludeoneormorecomponents(seenextsection).Butthesearethebasicbuildingblocksofanengine.Thefigurebelowshowsatypicaljetenginedesignillustratingthedifferentcomponents.航空发动机专业英语第18页2020/2/16Figure2.1air-breathingenginecomponents航空发动机专业英