three-dimensional models variations in a lean for analyzing the cyclic burn cng engine

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1、Three-DimensionalModelsVariationsinaLeanforAnalyzingtheCyclicBurnCNGEngineJournalofBeijingInstituteofTechnology,2007,Vo1.16,No.3Three—DimensionalModelsforAnalyzingtheCyclicVariations.LeanBurnCNGEng"ansinaeanBurnn~ineLIGuo—xiu(李国岫)(SchoolofMechanical,Electronic,YUYu—song(虞育松andControlEngine

2、ering,Beijing),LIUJian—ying(刘建英)JiaotongUniversity,Bering100044.China)Abstract:Three—dimensionalmodels,consistingoftheflamekernelformationmodel,flamekerneldevelop—mentmodelandnaturalgassinglestepreactionmodel,areusedtoanalyzethecontributionofcyclicequiva—lenceratiovariationstocyclicvariati

3、onsinthecompressednaturalgas(CNG)leanburnsparkignitionengine.Computationalresultsincludingthecontributionsofequivalenceratiocyclicvariationstoeachcombustionstageandeffectsofenginespeedtotheextentofcombustionvariationsarediscussed.Itisconcludedthattheequiva—lenceratiovariationsaffectmostlyt

4、hemainstageofcombustionandhardlyinfluenceinitialkerneldevelopmentstage.Keywords:three-dimensionalmodel;leanburnCNGengine;equivalenceratio;combustioncyclicvariationsCLCnumber:TK402Documentcode:AArticleID:1004—0579(2007)03—0274—05Cyclicvariabilityhaslongbeenrecognizedasthenormalphenomenaofth

5、eSIenginesandlimitstherangeofoperatingconditionsofsparkignitionan—gines[1-2].Theradicalreasonsforthecyclicvaria—tionsaretheexistenceoftherandomfactorssuchastheturbulenceparametersandtheequivalencera—tio[3-4].Itisworthnoticingthatreducingthecyclicvariationsinthecombustionprocesswouldimprove

6、thefuelconsumptionandthepollutantemis—sions[一.Withtheimpositionofmorestringentemissionregulationsinthenearfutureandthedevel—opmentoftheCNGSIengines,peoplehavetocon—ductmorethoroughresearchonCNGSIengines,as—peciallyonmechanismofthecyclicvariability.Inthispaper,weusedtheoriginalKIVA-Ⅲcode(de

7、velopedbyLosAlamosNationalLaborato—ries)[asthebasisoftheresearch.Throughaddingtheflamekernelformationmodelandthenaturalgasreactionmodeltothecode,modifyingtheenergyconservationequations(consideringtheheattransferfromflamekerneltotheelectrode),three—dimension—al