GASTurbineCombustion--燃气涡轮燃烧

GASTurbineCombustion---H.LdfebvreandDilipR.Ballal•Introduction•CombustorDevelopments•Combustorrequirements•Combustortypes&component•IndustrialchambersContentsIntroductionintakestroke,compression,Ignition,andexhauststrokeTheworkingfluid(air)isinitiallycompressedinthecompressor.Thenheatedinthecombustionchamber.Finally,itgoesthroughtheturbine.Theturbineconvertstheenergyofthegasintomechanicalwork.Partofthisworkisusedtodrivethecompressor.TheremainingpartisknownasthenetworkoftheGT.TwoimportanttypesofGT:–Industrialgasturbines–JetenginegasturbinesPrincipleofGToperationEarlyCombustorDevelopmentsPilotstartingjetVaporizingtubesAirEffluxgasesAtomizerSwirlvanesEffluxgasesAirStubpipesFigure1.1EarlyWhittlevaporizercombustor.Figure1.2EarlyWhittleatomizercombustor.•Inventedin1930byFrankWhittle•“Reverse-flow”typecombustor•Liquidfuel“→vapor→combustion•Athighpressurethroughvaporizingtube•Difficultyincontrollingthefuelflowrate•Pressure-swirlatomizer•Coolingholeandstubpipestoreducethegastemperature•UsingtomadethefirstBritishturbojetpoweredflightonMay15,1941FuelSandwichscoopsEffluxgasesAirFigure1.3Metrovickannularcombustor.•Using“srtaight-through”combustor•AddedDilutionair:FirstrowofscoopsprovidedairforcombustionSecondoneusefordilutionpurpose•Drawback:HighweightFigure1.2EarlyWhittleatomizercombustor.GermanySandwhichscoopsInletairEffluxgasesFigure1.5BMW003annularcombustor.AirentryEffluxgasesUpstreamfuelinjectionSwirlvanesAirinletFigure1.4Jumo004tubularcombustor.•Firstusedforaircraftpropulsionin1942onMe262•Firstenginestoemployaxialflowturbomachinery•Sixtubularcombustor→5.2MPa•Coolingairingformstubpipes•Annularcombustorfittedwith16equispaced,downstream-spraying,pressureatomizers•Lowpressureloss,butalsoafairlyhighlength/heightratioTheUnitedStatesGraduatedairadmissionInletairEffluxgasesFigure1.6GeneralElectricJ33tubularcombustor.SixfuelnozzlesCentralairtubeEffluxgasesInletairFigure1.7Pratt&WhitneyJ57tuboannularcombustor.•In1941,GEcompanyhadbuiltW2Bwith1600lb;•Straight-throughcombustorforJ33,J35engine.•J57engine,madebyP&W,employedeighttubularlinerslocatedwithinanannularcasing.•Eachlinerhadaperforatedtubealongitscentralaxisthat•extendedabouthalfwaydowntheliner.CombustorrequirementsFigure1.8Derivationofconventionalcombustorconfiguration.BasicDesignFeaturesPressureloss:Straight-wall→higherΔpDiffuser→reduceΔpPlainbaffle→AnchortheflameCombustionairCoolingairFlametubeCombustorrequirements1.High-combustionefficiency2.Reliableandsmoothignition,bothontheground3.Widestabilitylimits4.Lowpressureloss5.Anoutlettemperaturedistribution(patternfactor)thatistailoredtomaximizethelivesoftheturbinebladesandnozzleguidevanes6.Lowemissionsofsmokeandgaseouspollutantspecies7.Freedomfrompressurepulsationsandothermanifestationsofcombustion-inducedinstability8.Sizeandshapecompatiblewithengineenvelope9.Designforminimumcostandeaseofmanufacturing10.Maintainability11.Durability12.Petroleum,synthetic,andbiomass-basedmultifuelcapability.RequirementsCombustorrequirementsTypesofcombustor•Cylindricallinermountedconcentricallyinsideacylindricalcasing•Relativelylittletimeandmoneyisincurredintheirdevelopment.•Excessivelengthandweightleadtotheirmainapplicationistoindustrialunitswhereaccessibilityandeaseofmaintenanceareprimeconsiderations.•6to10tubularlinerswithasingleannularcasing•Canbecarriedoutwithverymodestairsupplies,usingjustasmallsegmentofthetotalchambercontainingoneormoreliners•ItsdifficulttoachieveasatisfactoryandconsistentairflowpatternTubular(or“can”)Tuboannular•Anannularlinerwithanannularcasing.•Idealformofchamber,becauseitscleanaerodynamiclayout,resultinlowerpressurelossthanothers.•Maindrawbackstemsfromtheheavybucklingloadontheouterliner,veryhighcostofsupplyingairatthelevelsofpressure,temperatureandflowraterequiredtotestlargeannularcombustionchambersatfull-loadconditions.TypesofcombustorFigure1.12CF6-50annularcombustorFigure1.13RB211annularcombustor.(CourtesyofRollsRoyceplc.)AnnularcomponentsofcombustorMaincomponentsofaconventionalcombustor.DiffuserPressureDrop:ΔP3-4=ΔPcold+ΔPhotΔPcoldIncurredinsimplypushingtheairthroughthecombustorDiffuser:≈0Liner:ΔP≈2.5~5%ΔPhotfundamentallossarisingfromtheadditionofheattoahigh-velocitystream=0.5U2(T4/T3-1)Function:•Reducethevelocityofthecombustorinletair;•Recoverasmuchofthedynamicpressureaspossible;•PresentthelinerwithasmoothandstableflowPressureloss:•Reductioninvelocityabout35%•Threeairpassages:inner,outerlinerannuliandcentralpassageforatomizationanddomecoolingDiffuserDiffusingflow(a)(b)Figure1.14Twobasictypesofannulardiffusers:(a)aerodynamic,(b)dump.•Reductioninvelocityabout50%•widelyusedbecauseoftheirhighertolerancetovariationsininletvelocityprofileandhardwaredimensions•Creationofatoroidalflowreversalthatentrainsandrecirculatesaportionofthehotcombustiongasestoprovidecontinuousignitiontotheincomingairandfuel.PrimaryZoneFigure1.15Lucasprimary-zoneairflowpattern.•Anchortheflameandprovidesufficienttime,temperature,andturbulencetoachievecompletecombustionoftheincomingfuel–airmixture.IntermediateZone:•Coolingandsentth